Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Conn

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Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Conn

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19-4653; 7/09
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
MAX9670/MAX9671 dual SCART matrices route audio video signals between set-top decoder chip external SCART connectors under control. Operating from 3.3V supply supply, MAX9670/MAX9671 consume 70mW during quiescent operation 471mW during average operation when driving typical signals into typical loads. Video input detection, video load detection, 2.5mW standby mode facilitate design intelligent, low-power set-top boxes. MAX9670/MAX9671 audio section contains buffered crosspoint route audio inputs audio outputs programmable volume control from -62dB steps. DirectDrive® output amplifiers create 2VRMS full-scale audio signal biased around ground, eliminating need bulky output capacitors reducing click-and-pop noise. zero-cross detection circuitry also further reduces clicks pops enabling audio sources switch only during zerocrossing. MAX9671 offers left right audio inputs. MAX9670/MAX9671 video section contains buffered crosspoint route video inputs video outputs. standard-definition video signals from settop decoder chip lowpass filtered remove out-of-band artifacts. MAX9670/MAX9671 also support slow-switching fast-switching signals. interrupt signal from MAX9670/MAX9671 informs microcontroller when system status changed. 2.5mW Standby Mode Consumption Programmable Audio Gain Control -62dB Audio Outputs) Clickless, Popless, DirectDrive Audio Video Input Video Load Detection Video Reconstruction Filter with 10MHz Passband 52dB Attenuation 27MHz 3.3V Supply Voltages
Features
70mW Quiescent Power Consumption
MAX9670/MAX9671
Ordering Information
PART MAX9670CTL+ TEMP RANGE +70°C PINPACKAGE TQFN-EP* AUDIO INPUTS
MAX9671CTH+ +70°C TQFN-EP* +Denotes lead(Pb)-free/RoHS-compliant package.
Exposed pad.
System Block Diagram
VVID 3.3V VAUD 3.3V
Applications
Set-Top Boxes Players
CHIP
INTERRUPT OUTPUT
MAX9670/MAX9671
RGB, Y/C, CVBS INTERFACE REGISTERS ACTIVITY MONITOR CVBS AUDIO (MAX9671 ONLY) AUDIO (MAX9670 ONLY) SLOW SWITCHING
SCART
VIDEO ENCODER
RGB, Y/C, CVBS
VIDEO FILTERS CROSSPOINT
FAST SWITCHING
STEREO AUDIO
SINGLE-ENDED STEREO AUDIO
AUDIO CROSSPOINT WITH DIRECTDRIVE OUTPUTS, VOLUME CONTROL
Y/C, CVBS RGB, Y/C, CVBS AUDIO SLOW SWITCHING
SCART
SLOW SWITCHING FAST SWITCHING
FAST SWITCHING
Typical Application Circuit appears data sheet.
CHARGE PUMP
DirectDrive registered trademark Maxim Integrated Products, Inc.
GNDVID
Maxim Integrated Products
pricing, delivery, ordering information, please contact Maxim Direct 1-888-629-4642, visit Maxim's website www.maxim-ic.com.
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
ABSOLUTE MAXIMUM RATINGS
VVID GNDVID.-0.3V EP.-0.3V +14V VAUD .-0.3V GNDVID .-0.1V +0.1V Video Inputs, VCRIN_FS GNDVID.-0.3V Audio Inputs .-1V SDA, SCL, DEV_ADDR, GNDVID .-0.3V TV_SS, VCR_SS .-0.3V (V12 0.3V) Current Video/Audio Inputs .±20mA C1P, C1N, CPVSS .±50mA Output Short-Circuit Current Duration Video Fast-Switching Outputs VVID, GNDVID.Continuous Audio Outputs VAUD, .Continuous TV_SS, VCR_SS V12, EP.Continuous Continuous Power Dissipation +70°C) 40-Pin TQFN-EP (derate 26.3mW/°C above +70°C) .2105.3mW 44-Pin TQFN-EP (derate 26.3mW/°C above +70°C).2222.2mW Operating Temperature Range.0°C +70°C Junction Temperature .+150°C Storage Temperature Range .-65°C +150°C Lead Temperature (soldering, 10s) .+300°C
Stresses beyond those listed under "Absolute Maximum Ratings" cause permanent damage device. These stress ratings only, functional operation device these other conditions beyond those indicated operational sections specifications implied. Exposure absolute maximum rating conditions extended periods affect device reliability.
ELECTRICAL CHARACTERISTICS
(V12 12V, VVID VAUD 3.3V, VGNDVID load, +70°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER Video Supply Voltage Range Audio Supply Voltage Range Supply Voltage Range SYMBOL VVID VAUD CONDITIONS Inferred from video PSRR test 3.6V Inferred from audio PSRR test 3.6V Inferred from slow-switching levels Normal operation; video output amplifiers enabled muted (Note VVID Quiescent Supply Current IVID_Q Standby mode, slow switch inputs Shutdown VAUD Quiescent Supply Current IAUD_Q Normal operation (Note Shutdown Normal operation (Note Slow-switching output low-level Slow-switching output medium-level 11.4 12.6 1500 UNITS
Quiescent Supply Current
I12_Q
Shutdown, +25°C VIDEO CHARACTERISTICS DC-COUPLED INPUT GNDVID VVID/2; inferred from gain test VVID VVID 3.135V VVID 3.3V 1.15
Input Voltage Range
1.15
VP-P
Input Current Input Resistance
0.3V, +25°C
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
ELECTRICAL CHARACTERISTICS (continued)
(V12 12V, VVID VAUD 3.3V, VGNDVID load, +70°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER AC-COUPLED INPUT Sync-Tip Clamp Level Sync Crush Input Clamping Current Maximum Input Source Resistance Input Voltage VCLP Sync-tip clamp Sync-tip clamp; percentage reduction sync pulse (0.3VP-P); guaranteed input clamping current measurement, +25°C Sync-tip clamp, 0.3V, +25°C Input sync-tip circuit must stable even source resistance high Bias circuit High-impedance input circuit Bias circuit High-impedance input circuit Guaranteed output voltage swing Guaranteed output voltage swing TV_R/C_OUT, TV_G_OUT, TV_B_OUT; first input signal VCR_R/C_IN, VCR_G_IN, VCR_B_IN; second signal ENC_R/C_IN, ENC_G_IN, ENC_B_IN Sync-tip clamp (VIN VCLP) Bias circuit Sync-tip clamp, measured output, VVID VCLP (VCLP +1.15V), VVID/2, GNDVID Measured output, VVID 3.135V, VCLP (VCLP 1.15V), VVID/2, GNDVID Output Voltage Swing Bias circuit, measured output, VVID (VBIAS 0.575V) (VBIAS 0.575V), VVID/2, GNDVID Measured output, VVID 3.135V, (VBIAS 0.575V) (VBIAS 0.575V), VVID/2, GNDVID Output Short-Circuit Current Output Resistance Output Leakage Current Power-Supply Rejection Ratio ROUT Output disabled (load detection active) VVID 3.6V 1.95 0.57 VVID 2.05 0.63 0.36 VVID SYMBOL CONDITIONS UNITS
MAX9670/MAX9671
Input Resistance CHARACTERISTICS Voltage Gain
Gain Mismatch Among Outputs
Output Level
0.30
0.51 1.78
2.243
2.358 VP-P
2.243
2.358
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
ELECTRICAL CHARACTERISTICS (continued)
(V12 12V, VVID VAUD 3.3V, VGNDVID load, +70°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER CHARACTERISTICS Filter Passband Flatness Filter Attenuation Slew Rate Settling Time Differential Gain Differential Phase Pulse-to-Bar Rating Pulse Response Response Nonlinearity Group Delay Distortion Glitch Impulse Caused Charge-Pump Switching Peak Signal Noise Power-Supply Rejection Ratio Output Impedance Video Crosstalk Reverse Isolation VOUT 2VP-P, 100kHz 5.5MHz VOUT 2VP-P, attenuation referred 100kHz 9.5MHz 27MHz 54MHz 0.15 V/µs Degrees pV-s SYMBOL CONDITIONS UNITS
VOUT 2VP-P, filter video path VOUT 2VP-P, settle 0.1% (Note 5-step modulated staircase, 4.43MHz 5-step modulated staircase, 4.43MHz 200ns, time 18µs, beginning 2.5% ending 2.5% time ignored 200ns 200ns, time 18µs, beginning 2.5% ending 2.5% time ignored 5-step staircase 100kHz 5MHz, outputs 2VP-P Measured outputs 100kHz 5MHz 100kHz, 100mVP-P 5MHz 4.43MHz SCART inputs encoder inputs, full-power mode with being looped through 4.43MHz Enable VCR_R/C_OUT pulldown through interface -0.707V +0.707V -0.707V +0.707V 20Hz 20kHz, 0.25VRMS input 0.25VRMS input, frequency where output -3dB referenced 1kHz sustained oscillations; series resistor output 3.95 -1.5
Pulldown Resistance AUDIO CHARACTERISTICS Voltage Gain Gain Mismatch Flatness Frequency Bandwidth Capacitive Drive
0.006
4.05 +1.5
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
ELECTRICAL CHARACTERISTICS (continued)
(V12 12V, VVID VAUD 3.3V, VGNDVID load, +70°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER Input Resistance Input Bias Current Input Signal Amplitude Output Level Power-Supply Rejection Ratio Signal-to-Noise Ratio Total Harmonic Distortion Plus Noise Output Impedance Volume Control Attenuation Step Volume Control Minimum Attenuation Volume Control Maximum Attenuation Mute Suppression Audio Crosstalk VIDEO-TO-AUDIO INTERACTION Crosstalk CHARGE PUMP Switching Frequency FAST SWITCHING Input Input High Level Input Current Output Voltage Output High Voltage Output Resistance Rise Time Fall Time SLOW SWITCHING Input Voltage Input Medium Voltage Input High Voltage GNDVID GNDVID +25°C 0.5mA 0.5mA VVID Video input: 15kHz, 1VP-P signal Audio input: 15kHz, 0.5VRMS signal 1kHz, 0.25VRMS input 1kHz, 0.25VRMS input SYMBOL CONDITIONS -0.707V +0.707V +25°C 1kHz, input signal, grounded 1kHz 1kHz, 0.25VRMS input, 20Hz 20kHz 3.33k, 1kHz, 0.25VRMS input 3.33k, 1kHz, 0.5VRMS input 1kHz Programmable gain SCART volume control from -62dB 0.002 0.001 UNITS VRMS
MAX9670/MAX9671
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
ELECTRICAL CHARACTERISTICS (continued)
(V12 12V, VVID VAUD 3.3V, VGNDVID load, +70°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER Input Current Output Voltage Output Medium Voltage Output High Voltage DIGITAL INTERFACE Input High Voltage Input Voltage Input Hysteresis Input Leakage Current Input Capacitance 0.1VVID 3.3V, 0.1VVID 3.3V pins fast-mode devices must obstruct lines switched off, +25°C ISINK VHYS IIH, +25°C 0.06 VVID VVID VVID 11.4V 12.6V 11.4V 12.6V 11.4V 12.6V SYMBOL CONDITIONS UNITS
Input Current
Output Voltage Serial-Clock Frequency Free Time Between STOP START Condition Hold Time, (Repeated) START Condition Period Clock High Period Clock Setup Time Repeated START Condition Data Hold Time Data Setup Time Fall Time Transmitting Setup Time STOP Condition Pulse Width Spike Suppressed
fSCL tBUF tHD, tLOW tHIGH tSU, tHD, tHD, tSU,
(Note ISINK 6mA, total capacitance line measured between 0.3VVID 0.7VVID
Input filters inputs suppress noise spikes less than 50ns
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
ELECTRICAL CHARACTERISTICS (continued)
(V12 12V, VVID VAUD 3.3V, VGNDVID load, +70°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER OTHER DIGITAL DEV_ADDR Level DEV_ADDR High Level DEV_ADDR Input Current Interrupt Output Voltage Interrupt Output Leakage Current +25°C 0.5mA high impedance, +25°C VVID VVID SYMBOL CONDITIONS UNITS
MAX9670/MAX9671
Note Note Note Note
devices 100% production tested +25°C. Specifications over temperature limits guaranteed design. Normal operation mode full power with input video load detection active. settling time measured from input swing 0.1% final value output. master device must provide hold time least 300ns signal (referred signal) bridge undefined region SCL's falling edge.
Typical Operating Characteristics
(VVID VAUD 3.3V, 12V, VGNDVID video load GNDVID, audio load +25°C, unless otherwise noted.)
SMALL-SIGNAL GAIN FREQUENCY
VOUT 100mVP-P GAIN (dB) FILTER 100k FREQUENCY (Hz) 100M FILTER GAIN (dB)
MAX9670 toc01
SMALL-SIGNAL GAIN FLATNESS FREQUENCY
MAX9670 toc02
LARGE-SIGNAL GAIN FREQUENCY
VOUT 2VP-P FILTER GAIN (dB) FILTER
MAX9670 toc03
FREQUENCY (Hz) FILTER FILTER VOUT 100mVP-P
100M
100k
FREQUENCY (Hz)
100M
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Typical Operating Characteristics (continued)
(VVID VAUD 3.3V, 12V, VGNDVID video load GNDVID, audio load +25°C, unless otherwise noted.)
LARGE-SIGNAL GAIN FLATNESS FREQUENCY
MAX9670 toc04
VIDEO CROSSTALK FREQUENCY
MAX9670 toc05
GROUP DELAY FREQUENCY
VOUT 2VP-P DELAY (ns) FILTER FILTER
MAX9670 toc06
GAIN (dB) FREQUENCY (Hz) FILTER FILTER
DELAY (ns) -100 -120
VOUT 100mVP-P
HOSTILE
100M
100k
100M
100k
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
VIDEO POWER-SUPPLY REJECTION RATIO FREQUENCY
PSRR (dB) 100k 100M FREQUENCY (Hz) DIFFERENTIAL GAIN 1.97 1.96 FILTER FILTER
MAX9670 toc07
VIDEO VOLTAGE GAIN TEMPERATURE
MAX9670 toc08
VIDEO OUTPUT VOLTAGE INPUT VOLTAGE
MAX9670 toc09
2.04 2.03 OUTPUT VOLTAGE 2.02 2.01 2.00 1.99 1.98
OUTPUT VOLTAGE
INPUT VOLTAGE
INPUT VOLTAGE
DIFFERENTIAL GAIN PHASE
DIFFERENTIAL GAIN -0.1 -0.2 -0.3 -0.2 -0.4 -0.6
MAX9670 toc10
DIFFERENTIAL GAIN PHASE
-0.1 -0.2 -0.3 -0.2 -0.4 -0.6
MAX9670 toc11
WITH FILTER
MAX9670 toc12
VIDEO INPUT 200mV/div
DIFFERENTIAL PHASE (deg)
DIFFERENTIAL PHASE (deg)
VIDEO OUTPUT 500mV/div
80ns/div
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
Typical Operating Characteristics (continued)
(VVID VAUD 3.3V, 12V, VGNDVID video load GNDVID, audio load +25°C, unless otherwise noted.)
FILTER
MAX9670 toc13
MAX9670/MAX9671
12.5T WITH FILTER
MAX9670 toc14
VIDEO INPUT 200mV/div
VIDEO INPUT 200mV/div
VIDEO OUTPUT 500mV/div
VIDEO OUTPUT 500mV/div
80ns/div
1µs/div
12.5T FILTER
MAX9670 toc15
NTC7 WITH FILTER
MAX9670 toc16
VIDEO INPUT 200mV/div
VIDEO INPUT 500mV/div
VIDEO OUTPUT 500mV/div
VIDEO OUTPUT 1V/div
1µs/div
10µs/div
NTC7 FILTER
MAX9670 toc17
FIELD SQUARE WAVE
MAX9670 toc18
VIDEO INPUT 500mV/div
VIDEO INPUT 500mV/div
VIDEO OUTPUT 1V/div
VIDEO OUTPUT 1V/div
10µs/div
2ms/div
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Typical Operating Characteristics (continued)
(VVID VAUD 3.3V, 12V, VGNDVID video load GNDVID, audio load +25°C, unless otherwise noted.)
VIDEO INPUT SYNC-TIP CLAMP VOLTAGE TEMPERATURE
MAX9670 toc19
VIDEO INPUT BIAS VOLTAGE TEMPERATURE
INPUT BIAS VOLTAGE (mV)
MAX9670 toc20
INPUT CLAMP VOLTAGE (mV)
TEMPERATURE (°C)
TEMPERATURE (°C)
VIDEO INPUT SYNC-TIP CLAMP CURRENT TEMPERATURE
MAX9670 toc21
VIDEO INPUT SYNC-TIP CLAMP CURRENT INPUT VOLTAGE
INPUT CLAMP CURRENT (µA)
MAX9670 toc22
INPUT CLAMP CURRENT (mA)
TEMPERATURE (°C)
INPUT VOLTAGE
VIDEO OUTPUT BIAS VOLTAGE TEMPERATURE
MAX9670 toc23
AUDIO LARGE-SIGNAL GAIN FREQUENCY
MAX9670 toc24
1.50 1.49 OUTPUT BIAS VOLTAGE 1.48
GAIN (dB)
1.47 1.46 1.45 1.44 1.43 1.42 TEMPERATURE (°C)
100k
FREQUENCY (Hz)
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
Typical Operating Characteristics (continued)
(VVID VAUD 3.3V, 12V, VGNDVID video load GNDVID, audio load +25°C, unless otherwise noted.)
AUDIO CROSSTALK FREQUENCY
MAX9670 toc25
MAX9670/MAX9671
TOTAL HARMONIC DISTORTION PLUS NOISE FREQUENCY
0.25VRMS
MAX9670 toc26
CROSSTALK (dB)
0.01 THD+N TVIN TVOUT
-100 -120 FREQUENCY (Hz) 100k
0.001
TVIN VCROUT
0.0001 FREQUENCY (Hz) 100k
VAUD POWER-SUPPLY REJECTION RATIO (INPUT REFERRED) FREQUENCY
VAUD 3.3V 100mVP-P PSRR (dB) -100 -120 FREQUENCY (Hz) 100k
MAX9670 toc27
VVID QUIESCENT SUPPLY CURRENT TEMPERATURE
MAX9670 toc28
CURRENT (mA)
TEMPERATURE (°C)
VAUD QUIESCENT SUPPLY CURRENT TEMPERATURE
MAX9670 toc29
QUIESCENT SUPPLY CURRENT TEMPERATURE
CURRENT (nA)
MAX9670 toc30
CURRENT (mA)
TEMPERATURE (°C)
TEMPERATURE (°C)
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Description
MAX9670 MAX9671 NAME DEV_ADDR FUNCTION Bidirectional Data I/O. Output open drain tolerates 3.6V. Clock Input Device Address Input. Connect GNDVID, VVID, SCL. Table Interrupt Output. This open-drain output that pulls down GNDVID indicate change slow switching fast switching input, activity status composite video inputs, load status composite video outputs. Audio Supply. Connect 3.3V supply. Bypass with 10µF aluminum electrolytic capacitor 0.47µF ceramic capacitor Charge-Pump Flying Capacitor Positive Terminal. Connect 0.47µF capacitor from C1N. Charge-Pump Flying Capacitor Negative Terminal. Connect 0.47µF capacitor from C1N. Charge-Pump Negative Power Supply. Bypass with ceramic capacitor Encoder Left-Channel Audio Input Encoder Right-Channel Audio Input SCART Left-Channel Audio Input SCART Right-Channel Audio Input SCART Left-Channel Audio Input SCART Right-Channel Audio Input SCART Left-Channel Audio Output SCART Left-Channel Audio Output SCART Right-Channel Audio Output SCART Right-Channel Audio Output SCART Bidirectional Slow-Switch Signal +12V Supply Slow Switching Circuit. Bypass with 10µF 0.47µF ceramic capacitor SCART Bidirectional Slow-Switch Signal SCART Fast-Switching Logic Output Connection. Leave unconnected. SCART Fast-Switching Logic Input Encoder Blue Video Input Encoder Green Video Input SCART Blue Video Input SCART Green Video Input SCART Blue Video Output SCART Green Video Output
VAUD CPVSS ENC_INL ENC_INR TV_INL TV_INR VCR_INL VCR_INR TV_OUTL VCR_OUTL VCR_OUTR TV_OUTR TV_SS VCR_SS TVOUT_FS N.C. VCRIN_FS ENC_B_IN ENC_G_IN VCR_B_IN VCR_G_IN TV_B_OUT TV_G_OUT
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
Description (continued)
MAX9670 MAX9671 NAME GNDVID VCR_R/C_IN VVID ENC_C_IN ENC_R/C_IN TV_R/C_OUT VCR_R/C_OUT TV_Y/CVBS_OUT VCR_Y/CVBS_IN TV_Y/CVBS_IN ENC_Y_IN ENC_Y/CVBS_IN Video Ground SCART Red/Chroma Video Input Video Digital Supply. Connect 3.3V supply. Bypass with parallel 0.1µF ceramic capacitors GNDVID. VVID also serves digital supply interface. Encoder Chroma Video Input Encoder Red/Chroma Video Input SCART Red/Chroma Video Output SCART Red/Chroma Video Output SCART Luma/Composite Video Output SCART Luma/Composite Video Input SCART Luma/Composite Video Input Encoder Luma Video Input Encoder SCART Luma/Composite Video Input Exposed Pad. exposed internal ground audio amplifiers charge pump. low-impedance connection between ground required proper isolation. FUNCTION
MAX9670/MAX9671
VCR_Y/CVBS_OUT SCART Luma/Composite Video Output
Detailed Description
MAX9670/MAX9671 represents Maxim's third generation SCART audio/video (A/V) switches. Under control, these devices route audio, video, control information between set-top decoder chip SCART connectors. audio signals left audio right audio. video signals composite video with blanking sync (CVBS) component video (red, green, blue). S-video (Y/C) transported across SCART interface CVBS reassigned luma reassigned chroma (C). Support S-video optional. slow-switch signal fast-switch signal carry control information. slowswitch signal 12V, three-level signal that indicates whether picture aspect ratio 16:9 causes television internal source such antenna. fast-switch signal indicates whether television should display CVBS signals. CVBS, left audio, right audio full duplex. other signals half duplex. Therefore, device link must designated transmitter, other device must designated receiver. power consumption advanced monitoring functions MAX9670/MAX9671 enable cre-
ation lower power set-top boxes, televisions, players. Unlike competing SCART ICs, audio video circuits MAX9670/MAX9671 operate entirely from 3.3V rather than from 12V. Only slow-switch circuit MAX9670/MAX9671 requires supply. MAX9670/MAX9671 also have circuits that detect activity CVBS inputs, loads CVBS outputs, level slow-switch signals. signal informs microcontroller there changes that microcontroller intelligently decide whether power power down equipment. addition, MAX9670/MAX9671 have DirectDrive audio circuitry eliminate click-and-pop noise. With DirectDrive, bias audio line outputs always ground, matter whether MAX9670/ MAX9671 being powered powered down. Conventional audio line output drivers that operate from single supply require series AC-coupling capacitors. During power-up, bias AC-coupling capacitor moves from ground positive voltage, during power-down, opposite occurs. changing bias usually causes audible transient.
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
MUTE ENC_INL MUTE VCR_INL (0.5VRMS FULL-SCALE INPUT) VOLUME CONTROL -62dB MUTE VOLUME CONTROL -62dB MUTE TV_OUTL
(2VRMS FULL-SCALE OUTPUT) TV_OUTR
*TV_INL
MUTE ENC_INR (2VRMS FULL-SCALE OUTPUT) VCR_INR MUTE *TV_INR DEV_ADDR REGISTER CONTROL
VCR_OUTL
VCR_OUTR
VAUD CPVSS *MAX9671 ONLY. CHARGE PUMP
MAX9670/MAX9671
Figure MAX9670/MAX9671 Audio Section Functional Diagram
Audio Section
MAX9670 audio circuit essentially stereo, 2-by-2, nonblocking, audio crosspoint with output drivers. encoder (stereo audio DAC) input sources, outputs SCART connector SCART connector. Figure MAX9671 audio circuit similar that MAX9670 except that stereo, 3-by-2,
nonblocking audio crosspoint with third input source. integrated charge pump inverts +3.3V supply create -3.3V supply. audio circuit operates from bipolar supplies audio signal always biased ground.
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
Audio Outputs MAX9670/MAX9671 audio output amplifiers feature Maxim's patented DirectDrive architecture, thereby eliminating need output-coupling capacitors required conventional single-supply audio line drivers. internal charge pump inverts positive supply (VAUD), creating negative supply (CPVSS). audio output amplifiers operate from these bipolar supplies with their outputs biased about audio ground (Figure benefit this audio ground bias that amplifier outputs have component. DC-blocking capacitors required with conventional audio line drivers unnecessary, conserving board space, reducing system cost, improving frequency response.
Conventional single-supply audio line drivers have their outputs biased about nominal voltage (typically half supply) maximum dynamic range. Large coupling capacitors needed block this bias. Clicks pops created when coupling capacitors charged during power-up discharged during power-down. MAX9670/MAX9671 features low-noise charge pump that requires only small ceramic capacitors. 580kHz switching frequency well beyond audio range does interfere with audio signals. switch drivers feature controlled switching speed that minimizes noise generated turn-on turn-off transients. SCART standard specifies 2VRMS full-scale audio signals. audio circuits process 0.5V full-scale audio signals internal MAX9670/MAX9671, gain-of-4 output amplifiers restore audio signals full-scale 2VRMS. select which audio input source routed SCART connector, write bits Audio Control register (01h). select which audio input source routed SCART connector, write bits Audio Control register (01h). power-on default audio outputs muted (the inputs output amplifiers connected audio ground). Tables
MAX9670/MAX9671
VDD/2
CONVENTIONAL DRIVER-BIASING SCHEME
+VDD
VOUT
2VDD
-VDD
DirectDrive BIASING SCHEME
Figure Conventional Driver Output Waveform MAX9670/ MAX9671 Output Waveform.
Clickless Switching audio channel incorporates zero-crossing detect (ZCD) circuit that minimizes click noise abrupt signal level changes that occur when switching between audio signals arbitrary moment.
implement zero-crossing function when switching audio signals, high (Audio Control register 00h, Then mute high (Audio Control register 00h, Next, wait sufficient period time audio signal cross zero. This period function audio signal path's low-frequency corner (fL3dB). Thus, fL3dB 20Hz, time period wait zero-crossing detect 1/20Hz 50ms. After wait period, select audio source audio channel writing bits Audio Control register (01h). Finally, clear mute (Audio Control register, 00h, leave (Audio Control register 00h, high. MAX9670/MAX9671 switches signal mute next zero crossing. Tables
Volume Control Volume control programmable from -62dB steps through interface. block consists resistive ladder network generate volume control steps, unity gain buffer isolate input from resistive ladder, switches (MPLx MNLx) that select nodes resistive ladder, logic decode volume control value. Table
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
ACTIVITY DETECT ACTIVITY DETECT ACTIVITY DETECT ACTIVITY DETECT TV_Y/CVBS_IN VCR_Y/CVBS_IN ENC_Y/CVBS_IN ENC_Y_IN CLAMP CLAMP 2V/V CLAMP CLAMP MUTE LOAD SENSE 2V/V VCR_Y/CVBS_OUT TV_Y/CVBS_OUT LOAD SENSE
MAX9670/MAX9671
VCR_R/C_IN ENC_R/C_IN ENC_C_IN
CLAMP/BIAS 2V/V CLAMP/BIAS CLAMP/BIAS MUTE 2V/V VCR_R/C_OUT TV_R/C_OUT
VCR_G_IN ENC_G_IN
CLAMP 2V/V CLAMP MUTE TV_G_OUT
VCR_B_IN ENC_B_IN
CLAMP 2V/V CLAMP MUTE VVID 1V/V GNDVID TVOUT_FS TV_B_OUT
VCRIN_FS 0.7V 1V/V 1V/V VCR_SS TV_SS
Figure MAX9670/MAX9671 Video Section Function Diagram
Video Section
video circuit routes different video formats between set-top decoder, SCART connector,
SCART connector. also routes slow-switch fast-switch control information. Figure
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
Video Inputs Whether incoming video signal AC-coupled DC-coupled into MAX9670/MAX9671 depends upon origin, format, voltage range video signal. Table below shows recommended connections. Always AC-couple external video signal through 0.1µF capacitor because voltage well defined (see Typical Application Circuit example, video transmitter circuit might have different ground than video receiver, thereby level shifting bias. 60Hz power line might cause video signal change bias slowly. Internal video signals that between DC-coupled. Most video DACs generate video signals between because video sources current into ground-referenced resistor. minority video DACs that generate video signals between 2.3V 3.3V because video sinks current from VVID-referenced resistor, AC-couple video signal MAX9670/MAX9671. MAX9670/MAX9671 restore level incoming, AC-coupled video signals with either transparent sync-tip clamps bias circuits. When using ACcoupled input, transparent sync-tip clamp automatically clamps input signal minimum ground, preventing from going lower. small current pulls down input prevent AC-coupled signal from drifting outside input range part. sync-tip clamps with CVBS, RGB, luma signals.
transparent sync-tip clamp transparent when incoming video signal DC-coupled above ground. Under such conditions, clamp never activates. Therefore, outputs video DACs that generate signals between directly connected MAX9670/MAX9671 inputs. bias circuit accepts AC-coupled chroma, which subcarrier with color information modulated onto bias voltage bias circuits around 600mV. ENC_R/C_IN VCR_R/C_IN receive either video signal chroma video signal. input configuration writing bits Video Input Control register (08h). Tables MAX9670/MAX9671 also have video input detection. When activated, activity detect circuits check sync present incoming CVBS signals. then there valid video signal. Read bits Video Activity Status register (0Fh) determine status CVBS inputs. Table high-impedance mode, inputs MAX9670/ MAX9671 distort video signal case outputs video also connected another video circuit such high-definition video filter amplifier. SCART Set-Top with Analog Outputs section. inputs high-impedance mode biased VVID/3, which sufficiently above ground that diodes never forward biases video signal changes. input resistance 222k, which presents negligible loading video current DAC.
MAX9670/MAX9671
Video Reconstruction Filter video outputs set-top decoder chip need lowpass-filtered reject out-of-band noise. MAX9670/MAX9671 integrate sixth-order, Butterworth filters. filter passband (±1dB) typically 5.5MHz, attenuation 27MHz 52dB. filters suited standard-definition video. Video Outputs video output amplifiers both source sink load current, allowing output loads ACcoupled. amplifier output stage needs around 300mV headroom from either supply rail. video signals with sync pulse, sync typically 300mV, shown Figure chroma signal, blank level typically 1.5V, shown Figure supply voltage greater than 3.135V below 3.3V supply), each amplifier drive DC-coupled video loads ground. supply less than 3.135V, each amplifier drive only DC-coupled AC-coupled video load. SCART standard allows video signals have superimposed component within Therefore, most video signals DC-coupled output. unlikely event that video signal needs AC-coupled, coupling capacitors should 220µF greater keep highpass filter formed 37.5 equivalent resistance video transmission line corner frequency 4.8Hz below keep well below 25Hz frame rate standard. CVBS outputs have load sense circuits. enabled, each load sense circuit checks load eight times second connecting internal pullup resistor output 1ms. output pulled load present. output stays low, load connected. Read bits determine load status. Table selection video sources that sent SCART connector controlled bits
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Video Input Control register (06h) while selection video sources that sent SCART connector controlled bits Video Input Control register (08h). Tables video outputs enabled disabled bits through Output Enable register (0Dh). Table fast-switching signal just used switch between CVBS signal sources. source fast-switching signal writing bits Video Output Control register (07h). fast-switching signal SCART connector enabled disabled Output Enable register (0Dh). Tables
Slow Switching MAX9670/MAX9671 support 933-1, Amendment three-level slow switching that selects aspect ratio display (TV). Under control, MAX9670/MAX9671 slow-switching output voltage level. Table shows valid input levels slow-switching signal corresponding operating modes display device.
bidirectional ports available slow-switching signals VCR. slow-switching input status continuously read stored Status register (0Eh). slow-switching outputs logic level high impedance writing Video Output Control register (07h) Video Output Control register (09h). When enabled, becomes active voltage level changes TV_SS VCR_SS. Tables
Serial Interface
MAX9670/MAX9671 feature I2C/SMBusTM-compatible, 2-wire serial interface consisting serial-data line (SDA) serial-clock line (SCL). facilitate communication between MAX9670/ MAX9671 master clock rates 400kHz. Figure shows 2-wire interface timing diagram. master generates initiates data transfer bus. master device writes data MAX9670/ MAX9671 transmitting START condition, proper slave address with followed register address then data word. Each transmit sequence framed START STOP condition. Each word transmitted MAX9670/MAX9671 bits long followed acknowledge clock pulse. master reads from MAX9670/MAX9671 transmitting slave address with register address register read, REPEATED START (Sr) condition, slave address with followed series pulses. MAX9670/MAX9671 transmit data sync with master-generated pulses. master acknowledges receipt each byte data. Each read sequence framed START
Fast Switching fast-switching signal originally used switch between CVBS signals pixel-by-pixel basis that on-screen display (OSD) information could inserted. Since modern set-top decoder chips have integrated circuitry, there need create information using older technique. Now,
MAX9670 fig04
MAX9670 fig05
INPUT 500mV/div
INPUT 200mV/div
OUTPUT 500mV/div
OUTPUT 200mV/div
20µs/div
10µs/div
Figure MAX9670/MAX9671 Video Output with CVBS Signal, Multiburst Video Test Signal Shown
Figure MAX9670/MAX9671 Video Output with Chroma Signal, Multiburst Video Test Signal Shown
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
tSU, tLOW tHD, START CONDITION tHIGH REPEATED START CONDITION STOP CONDITION START CONDITION tHD, tSU, tBUF tHD, tSU,
Figure Serial-Interface Timing Diagram
REPEATED START (Sr) condition, acknowledge acknowledge, STOP condition. operates both input open-drain output. pullup resistor, typically greater than 500, required bus. operates only input. pullup resistor, typically greater than 500, required there multiple masters bus, master single-master system open-drain output. Series resistors line with optional. Series resistors protect digital inputs MAX9670/MAX9671 from high-voltage spikes lines, minimize crosstalk undershoot signals.
Figure START, STOP, REPEATED START Conditions
Transfer data transferred during each cycle. data must remain stable during high period pulse. Changes while high control signals (see START STOP Conditions section). idle high when busy. START STOP Conditions idle high when use. master initiates communication issuing START condition. START condition high-to-low transition with high. STOP condition low-tohigh transition while high (Figure START condition from master signals beginning transmission MAX9670/MAX9671. master terminates transmission, frees bus, issuing STOP condition. remains active REPEATED START condition generated instead STOP condition.
Early STOP Conditions MAX9670/MAX9671 recognize STOP condition point during data transmission except STOP condition occurs same high pulse START condition. proper operation, send STOP condition during same high pulse START condition. Slave Address slave address defined most significant bits (MSBs) followed read/write (R/W) bit. configure MAX9670/MAX9671 read mode. configure MAX9670/MAX9671 write mode. slave address always first byte information sent MAX9670/MAX9671 after START REPEATED START condition. MAX9670/MAX9671 slave address configurable with DEV_ADDR. Table shows possible slave addresses MAX9670/MAX9671.
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Acknowledge acknowledge (ACK) clocked that MAX9670/MAX9671 handshake receipt each byte data when write mode (see Figure MAX9670/MAX9671 pull down during entire master-generated ninth clock pulse previous byte successfully received. Monitoring allows detection unsuccessful data transfers. unsuccessful data transfer occurs receiving device busy system fault occurred. event unsuccessful data transfer, master retry communication. master pulls down during ninth clock cycle acknowledge receipt data when
CLOCK PULSE ACKNOWLEDGMENT
MAX9670/MAX9671 read mode. acknowledge sent master after each read byte allow data transfer continue. acknowledge sent when master reads final byte data from MAX9670/MAX9671, followed STOP condition.
Write Data Format write MAX9670/MAX9671 consists transmitting START condition, slave address with data byte configure internal register address pointer, more data bytes, STOP condition. Figure illustrates proper frame format writing byte data MAX9670/MAX9671. Figure illustrates frame format writing bytes data MAX9670/ MAX9671.
slave address with indicates that master intends write data MAX9670/ MAX9671. MAX9670/MAX9671 acknowledge receipt address byte during master-generated ninth pulse. second byte transmitted from master configures MAX9670/MAX9671's internal register address pointer. pointer tells MAX9670/MAX9671 where write next byte data. acknowledge pulse sent MAX9670/MAX9671 upon receipt address pointer data.
START CONDITION
ACKNOWLEDGE
ACKNOWLEDGE
Figure Acknowledge
ACKNOWLEDGE FROM MAX9670/MAX9671 ACKNOWLEDGE FROM MAX9670/MAX9671 SLAVE ADDRESS ACKNOWLEDGE FROM MAX9670/MAX9671 REGISTER ADDRESS DATA BYTE BYTE
Figure Writing Byte Data MAX9670/MAX9671
ACKNOWLEDGE FROM MAX9670/MAX9671 ACKNOWLEDGE FROM MAX9670/MAX9671 ACKNOWLEDGE FROM MAX9670/MAX9671 SLAVE ADDRESS REGISTER ADDRESS ACKNOWLEDGE FROM MAX9670/MAX9671
DATA BYTE BYTE
DATA BYTE BYTE
AUTOINCREMENT INTERNAL REGISTER ADDRESS POINTER
Figure Writing Bytes Data MAX9670/MAX9671
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
ACKNOWLEDGE FROM MAX9670/MAX9671 SLAVE ADDRESS ACKNOWLEDGE FROM MAX9670/MAX9671 REGISTER ADDRESS ACKNOWLEDGE FROM MAX9670/MAX9671 SLAVE ADDRESS ACKNOWLEDGE FROM MASTER
DATA BYTE BYTE
REPEATED START
AUTOINCREMENT INTERNAL REGISTER ADDRESS POINTER
Figure Reading Indexed Byte Data from MAX9670/MAX9671
ACKNOWLEDGE FROM MAX9670/MAX9671 SLAVE ADDRESS
ACKNOWLEDGE FROM MAX9670/MAX9671 REGISTER ADDRESS
ACKNOWLEDGE FROM MAX9670/MAX9671 SLAVE ADDRESS DATA BYTE BYTE AUTOINCREMENT INTERNAL REGISTER ADDRESS POINTER
REPEATED START
Figure Reading Bytes Indexed Data from MAX9670/MAX9671
third byte sent MAX9670/MAX9671 contains data that written chosen register. acknowledge pulse from MAX9670/MAX9671 signals receipt data byte. address pointer autoincrements next register address after each received data byte. This autoincrement feature allows master write sequential register address locations within continuous frame. master signals transmission issuing STOP condition.
addresses higher than results repeated reads from dummy register containing data. master acknowledges receipt each read byte during acknowledge clock pulse. master must acknowledge correctly received bytes except last byte. final byte must followed acknowledge from master then STOP condition. Figures illustrate frame format reading data from MAX9670/MAX9671.
Read Data Format master presets address pointer first sending MAX9670/MAX9671's slave address with followed register address after START condition. MAX9670/MAX9671 acknowledges receipt slave address register address pulling during ninth clock pulse. REPEATED START (Sr) condition then sent followed slave address with MAX9670/MAX9671 transmits contents specified register. Transmitted data valid rising edge master-generated serial clock (SCL). address pointer autoincrements after each read data byte. This autoincrement feature allows registers read sequentially within continuous frame. STOP condition issued after number read data bytes. STOP condition issued followed another read operation, first data byte read from register address location previous transaction subsequent reads autoincrement address pointer until next STOP condition. Attempting read from register
Interrupt Output
When interrupt enabled modes INT, which open-drain output, pulls under following conditions: slow-switch signals change value, CVBS input signals detected disappear, CVBS output loads added removed. When interrupt enabled mode pulls only when slow-switch signal changes value. Enable writing into register 01h. Table interrupt cleared reading register 0Fh.
Applications Information
Audio Inputs maximum full-scale audio signal that applied audio inputs 0.5V biased ground. recommended application circuit attenuate bias incoming audio signal shown Figure
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
STEREO AUDIO DACS 6.65k ENC_INL 6.65k ENC_INR
MAX9670
VALUES CS4334/5/8/9: 4.53k, PCM1742: 5.57k,
Figure Application circuit connect audio source audio inputs. capacitor connected ground-referenced resistors biases audio signal ground. resistors attenuate audio signal.
considers this condition illegal does loop through signals. finite state machine (Figure controls operation MAX9670/MAX9671. State always initial state when MAX9670/MAX9671 enter standby mode. Table shows values registers state state machine sets other registers correct values loop through audio/video signals states (see Tables When MAX9670/MAX9671 leaves standby mode, values registers except register preserved that operation disturbed. example, standby mode, MAX9670 looping through audio/video signals from SCART SCART, microcontroller changes operating mode from standby mode full-power mode, audio/video signals continue looped through during after mode change. user does experience disruption audio video service. microcontroller turned standby mode because MAX9670/1 operate autonomously. Upon power-up, default operating mode standby mode.
MAX9670/MAX9671
audio path gain 4V/V that full scale audio output signal 2VRMS. less than 2VRMS, full scale desired audio outputs, full scale audio input signal should proportionately decreased below 0.5VRMS.
Operating Modes
MAX9670/MAX9671 four operating modes, which writing bits register 10h. Table
Full-Power Mode with Video Input Detection Video Load Detection this mode, MAX9670/MAX9671 fully interrupt enabled, goes active whenever slow-switch signal changes; CVBS signal appears disappears; CVBS load appears disappears. microcontroller decide whether change routing configuration operating mode MAX9670/MAX9671. Full-Power Mode Without Video Input Detection Video Load Detection This mode similar above mode except that video input detection video load detection active. interrupt enabled, goes active only when slow-switch signal changes.
Shutdown circuitry shutdown MAX9670/MAX9671 except interface, which designed with static CMOS logic. Except register 10h, which sets operating mode, values other registers preserved while entering, during, leaving shutdown mode. Standby Mode standby mode, MAX9670/MAX9671 monitor slow-switch signals decide whether loop through audio/video signals. slow switch input activity input), audio/video signals looped through from SCART SCART. slow-switch input activity, audio/video signals looped through from SCART SCART. neither slowswitch input slow switch input show activity, i.e., both inputs ground, signals looped through. both slow-switch input slow-switch input have activity, MAX9670/MAX9671
Power Consumption
quiescent power consumption average power consumption MAX9670/MAX9671 very because 3.3V operation low-power circuit design. Quiescent power consumption defined when MAX9670/MAX9671 operating without loads without audio video signals. Table shows quiescent power consumption operating modes. Average power consumption defined when MAX9670/MAX9671 drives typical signals into typical loads. Table shows average power consumption full-power mode Table shows input output conditions.
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
TV_SS ACTIVE VCR_SS ACTIVE TV_SS ACTIVE VCR_SS ACTIVE
STATE SEARCH AUDIO: INACTIVE VIDEO: INACTIVE SLOW SWITCH: LISTENING ACTIVITY FAST SWITCH: INACTIVE TV_SS ACTIVE VCR_SS ACTIVE TV_SS ACTIVE VCR_SS ACTIVE
TV_SS ACTIVE VCR_SS ACTIVE
TV_SS ACTIVE VCR_SS ACTIVE
TV_SS ACTIVE VCR_SS ACTIVE
TV_SS ACTIVE VCR_SS ACTIVE
STATE TV-TO-VCR AUDIO: VIDEO: SLOW SWITCH: FAST SWITCH: APPLICABLE
STATE VCR-TO-TV AUDIO: VIDEO: SLOW SWITCH: FAST SWITCH: TV_SS ACTIVE VCR_SS ACTIVE
TV_SS ACTIVE VCR_SS ACTIVE TV_SS ACTIVE VCR_SS ACTIVE
TV_SS ACTIVE VCR_SS ACTIVE
Figure Standby mode finite state machine. TV_SS active when either present. VCR_SS active when either present.
S-Video
MAX9670/MAX9671 support S-video from settop set-top VCR, set-top box. S-video included original SCART specifications added afterwards. consequence, luma signal S-video shares same SCART CVBS signal. Likewise, chroma signal shares same SCART
signal. pins that carry both CVBS luma have Y/CVBS their names, pins that carry chroma have their names. Now, Y/CVBS signals full duplex while signals half duplex. Therefore, S-video limited being half duplex. MAX9670/MAX9671 have transmit chroma signal receive chroma signal
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
0.1µF
VCR_R/C_IN ENC_R/C_IN ENC_C_IN
BIAS 2V/V BIAS BIAS
TV_R/C_OUT
SCART
2V/V
VCR_R/C_OUT
MAX9670/MAX9671
SCART
Figure Gain-of-2 amplifier VCR_R/C_OUT outputs chroma signal SCART connector. Notice that pulldown switch VCR_R/C_OUT open.
0.1µF
VCR_R/C_IN ENC_R/C_IN ENC_C_IN
BIAS 2V/V BIAS BIAS
TV_R/C_OUT
SCART
2V/V
VCR_R/C_OUT
MAX9670/MAX9671
SCART
Figure VCR_R/C_IN receives chroma signal from SCART connector. Notice that pulldown switch VCR_R/C_OUT closed that gain-of-2 amplifier off. chroma signal from SCART looped through SCART above configuration.
same SCART pin, same time. resistor connected VCR_R/C_OUT must back termination resistor when MAX9670/MAX9671 transmitting chroma signal input termination resistor when receiving chroma signal. Figure shows MAX9670/MAX9671 transmits chroma signal SCART connector while Figure shows MAX9670/MAX9671 receives chroma from SCART connector.
Write into register open pulldown switch VCR_R/C_OUT. close pulldown switch, write into register turn output amplifier, then write into register 09h. Tables
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
TV_OUTR
MAX9670/MAX9671
MONO AUDIO
TV_OUTL TV_Y/CVBS_OUT GREATER
SCART
GREATER
MODULATOR
Figure Application Circuit Connect CVBS Mono Audio from SCART Modulator
Interfacing Modulator
set-top modulates CVBS mono audio onto carrier (for example, channel simple application circuit provide needed signals (see Figure 17). resistor summer circuit between TV_OUTR TV_OUTL creates mono audio signal. resistor-divider ground TV_Y/CVBS_OUT creates video signal with normal amplitude. unique feature MAX9670/MAX9671 that facilitates this application circuit that audio video output amplifiers MAX9670/MAX9671 drive multiple loads both greater than 3.135V.
better protect MAX9670/MAX9671 against excess voltages during cable discharge condition events, series resistors inputs outputs SCART connector series resistors already present application circuit. Also, external protection diodes (for example, BAV99) inputs outputs SCART connector.
SCART Set-Top with Analog Outputs
set-top boxes with SCART connectors cinch connectors high-definition YPbPr outputs, triplevideo usually outputs either standard-definition signals that routed MAX9670/MAX9671 high-definition YPbPr signals that routed through high-definition filter amplifier like MAX9653 (see Figure 19). set-top devices have limited number video DACs, hence, bank triple-video DACs switches video format depending upon whether standard-definition high-definition YPbPr signals required. When signals desired, high-definition filter amplifier should turned that signals appear YPbPr connectors. MAX9653/MAX9654 well-suited this application because their video inputs high-impedance mode when shutdown.
Floating-Chassis Discharge Protection
Some set-top boxes have floating chassis problem which chassis connected earth ground. result, chassis charge 500V. When SCART cable connected SCART connector, charged chassis discharge through signal pin. equivalent circuit 2200pF capacitor charged 311V connected through less than signal pin. MAX9670/MAX9671 soldered when experiences such discharge. Therefore, current spike flows through both external internal protection devices absorbed supply bypass capacitors, which have high capacitance ESR.
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
0.1µF 3.3V 0.1µF 3.3V 0.1µF VAUD 7.68k
VVID
VAUD TV_INL (MAX9671 ONLY)
+3.3 CHIP TV_INR (MAX9671 ONLY)
2.55k 7.68k
VAUD CPVSS
MICROCONTROLLER
DEV_ADDR
2.55k TV_OUTR
CPVSS VAUD
VAUD TV_OUTL TV_SS TV_G_OUT TV_R/C_OUT GNDVID GNDVID GNDVID VVID TV_Y/CVBS_IN 0.1µF GNDVID GNDVID CPVSS CPVSS
VIDEO ENCODER ENC_Y/CVBS_IN ENC_R/C_IN ENC_G_IN ENC_B_IN ENC_Y_IN ENC_C_IN
TV_B_OUT
SCART
TVOUT_FS TV_Y/CVBS_OUT
MAX9670 MAX9671
GNDVID VCR_OUTR
GNDVID
VAUD
VAUD 7.68k VCR_INR CPVSS
STEREO AUDIO DACS
6.65k ENC_INL VCR_OUTL
2.55k
CPVSS
VAUD
VAUD 7.68k CPVSS
VCR_INL 2.55k ENC_INR VCR_SS VVID 0.1µF CPVSS SCART
6.65k
VCR_B_IN GNDVID VVID VCR_G_IN VVID GNDVID 0.1µF 0.1µF
VCR_R/C_IN
VVID GNDVID VVID GNDVID
VCR_R/C_OUT VALUES CS4334/5/8/9: 4.53k PCM1742: 5.57k
VCRIN_FS VCR_Y/CVBS_OUT VCR_Y/CVBS_IN GNDVID VVID 0.1µF CPVSS GNDVID VVID GNDVID
Figure Application Circuit Connect Series Resistors External Protection Diodes MAX9670/MAX9671 Outputs
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
0.1µF 0.1µF 3.3V SET-TOP CHIP 3.3V ENC_G_IN 0.1µF ENC_B_IN TV_B_OUT TV_G_OUT MAX9670/MAX9671 ENC_R/C_IN TV_R/C_OUT SCART CONNECTOR SET-TOP CHIP 3.3V 0.1µF 3.3V ENC_G_IN 0.1µF ENC_B_IN TV_B_OUT TV_G_OUT 0.1µF MAX9670/MAX9671 ENC_R/C_IN TV_R/C_OUT SCART CONNECTOR
INPUTS SYNC-TIP CLAMP
INPUTS HIGH IMPEDANCE
3.3V
3.3V
MAX9653 MAX9654 PBIN PRIN SHDN YOUT PBOUT PROUT 3.3V YPbPr OUTPUTS 0.1µF PRIN SHDN PROUT 0.1µF PBIN PBOUT 0.1µF MAX9653 MAX9654 YOUT YPbPr OUTPUTS
Figure Triple connected both MAX9670 MAX9653/MAX9654 high-definition video-filter amplifier. MAX9670/MAX9671 transmitting standard-definition signals while MAX9653/MAX9654 shutdown mode. MAX9670/MAX9671 transmitting signals, MAX9653/MAX9654 transmitting high-definition YPbPr signals.
Similarly, when YPbPr signals desired, ENC_R/C_IN, ENC_G_IN, ENC_B_IN MAX9670/MAX9671 should high-impedance mode setting register high those video inputs AC-coupled. high-impedance mode higher priority whether ENC_R/C_IN sync-tip clamp bias circuit mode (set register 08h). ENC_R/C_IN, ENC_G_IN, ENC_B_IN DC-coupled, inputs should left sync-tip clamp mode. outputs MAX9670 should muted shut down. either case, inactive device should distort video signals generated DACs.
stripes appear television screen, increase supply bypass capacitance. additional, smaller capacitor parallel with main bypass capacitor reduce digital supply noise because smaller capacitor lower equivalent series resistance (ESR) equivalent series inductance (ESL).
Layout Grounding
optimal performance, controlled-impedance traces video signal paths place input termination resistors output back-termination resistors close MAX9670/MAX9671. Avoid routing video traces parallel high-speed data lines. MAX9670/MAX9671 provide separate ground connections video audio supplies. best performance, separate ground planes each ground returns connect ground planes together single point. MAX9670/MAX9671 evaluation proven circuit board layout example. MAX9670/MAX9671 mounted using flow soldering wave soldering, ground via(s) should have finished hole size least 14mils insure adequate wicking soldering onto exposed pad. MAX9670/MAX9671 mounted using solder mask technique, requirement does apply. either case, good connection between exposed ground required minimize noise from coupling onto outputs.
Power-Supply Bypassing
MAX9670/MAX9671 feature single 3.3V supply operation require negative supply. supply SCART switching function. V12, place 0.1µF bypass capacitor close possible. Connect VAUD pins together 3.3V bypass with 10µF electrolytic capacitor parallel with 0.1µF ceramic capacitor audio ground. Bypass each VVID video ground with 0.1µF ceramic capacitor.
Using Digital Supply MAX9670/MAX9671 designed operate from noisy digital supplies. high PSRR (49dB 100kHz) allows MAX9670/MAX9671 reject noise from digital power supplies (see Typical Operating Characteristics). digital power supply very noisy
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Table Recommended Coupling Incoming Video Signals Input Circuit Configuration*
VIDEO ORIGIN External External External External Internal Internal Internal Internal Internal Internal Internal Internal FORMAT CVBS CVBS CVBS VOLTAGE RANGE Unknown Unknown Unknown Unknown 2.3V 3.3V 2.3V 3.3V 2.3V 3.3V 2.3V 3.3V COUPLING INPUT CIRCUIT CONFIGURATION Transparent sync-tip clamp Transparent sync-tip clamp Transparent sync-tip clamp Bias circuit Transparent sync-tip clamp Transparent sync-tip clamp Transparent sync-tip clamp Transparent sync-tip clamp Transparent sync-tip clamp Transparent sync-tip clamp Transparent sync-tip clamp Bias circuit
*Use 0.1µF capacitor AC-couple video signal into MAX9670/MAX9671.
Table Slow-Switching Modes
SLOW-SWITCHING SIGNAL VOLTAGE MODE Display device uses internal source such built-in tuner provide video signal. Display device uses video signal from SCART connector sets display 16:9 aspect ratio. Display device uses signal from SCART connector sets display aspect ratio.
12.6
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Table Slave Address
DEV_ADDR GNDVID VVID WRITE ADDRESS (hex) READ ADDRESS (hex)
Table Register Values State
REGISTER ADDRESS (hexadecimal) VALUE (binary) uuuu uuuu uuuu 1111 uuuu uuuu uuuu uu10 uuuu uuuu uuuu u010 0000 000u
Table Register Values State
REGISTER ADDRESS (hexadecimal) VALUE (binary) uuuu uuu0 uuuu 1011 uuuu uuuu uuu0 0u10 uuuu u011 uuuu u0MM 1100 001u
indicates that unchanged from previous state.
indicates that unchanged from previous state; Register (bit
Table Register Values State
REGISTER ADDRESS (hexadecimal) VALUE (binary) uuuu uuu0 uuuu 1101 uuu0 1010 uuu0 0uNN uuuu uuuu uuuu u110 0011 111u
indicates that unchanged from previous state; Register (bit
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Table Quiescent Power Consumption
OPERATING MODE Shutdown Standby mode with video activity (i.e., slow-switch slow-switch inputs ground). Standby mode power-on default. Full-power mode with input video detection video load detection active. Full-power mode without input video detection video load detection active. POWER CONSUMPTION (mW) 0.13
Table Average Power Consumption
OPERATING MODE Full-power mode with input video detection video load detection active. Full-power mode without input video detection video load detection active. POWER CONSUMPTION (mW)
2.83
Table Conditions Average Power Consumption Measurement
(MAX9670) NAME VAUD ENC_INL ENC_INR VCR_INL VCR_INR TV_OUTL VCR_OUTL VCR_OUTR TV_OUTR TV_SS VCR_SS TVOUT_FS VCRIN_FS ENC_B_IN ENC_G_IN VCR_B_IN VCR_G_IN TV_B_OUT TV_G_OUT GNDVID VCR_R/C_IN VVID TYPE Supply Input Input Input Input Output Output Output Output Output Supply Input Output Input Input Input Input Input Output Output Supply Input Supply SIGNAL 3.3V 0.25VRMS, 1kHz 0.25VRMS, 1kHz None None 1VRMS, 1kHz 1VRMS, 1kHz 1VRMS, 1kHz 1VRMS, 1kHz 3.3V flat field flat field None None flat field flat field None 3.3V LOAD ground ground ground ground ground ground ground ground
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Table Conditions Average Power Consumption Measurement (continued)
(MAX9670) NAME ENC_C_IN ENC_R/C_IN TV_R/C_OUT VCR_R/C_OUT VCR_Y/CVBS_OUT TV_Y/CVBS_OUT VCR_Y/CVBS_IN TV_Y/CVBS_IN ENC_Y_IN ENC_Y/CVBS_IN TYPE Input Input Output Output Output Output Input Input Input Input SIGNAL None flat field flat field flat field flat field flat field None None None flat field LOAD ground ground ground ground
Table Data Format Write Mode
REGISTER ADDRESS (hex) VCR_R/C_IN clamp used used volume control audio output mute
used used used
VCR_Y/ VCR_R/ CVBS_OUT C_OUT enable enable Operating mode
used
TV_R/ C_OUT enable
Interrupt audio selection audio selection enable used used used used video switch video switch fast switching used slow switching R/G/B ENC_R/C_IN highVCR video switch clamp impedance bias VCR_R/C_OUT slow ground switching used used used TV_Y/ TV_G_OUT TV_B_OUT TVOUT_FS used CVBS_OUT enable enable enable enable used
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Table Data Format Read Mode
REGISTER ADDRESS (hex) used Power-on reset
used ENC_Y_IN input video detection ENC_Y/ CVBS_IN input video detection
slow-switch input status CVBS output load CVBS input video detection
slow switch input status CVBS output load CVBS input video detection
used
Table Register 00H: Audio Control
DESCRIPTION Audio Mute Volume Control (power-on default) gain (power-on default) -2dB gain -4dB gain -6dB gain -8dB gain -10dB gain COMMENTS
Zero-Crossing Detector
Table Register 01H: Audio
DESCRIPTION Input Source Audio Input Source Audio Interrupt Enable audio audio (MAX9671 only) Mute (power-on default) Encoder audio audio audio (MAX9671 only) Mute (power-on default) Disabled (power-on default) Enabled COMMENTS Encoder audio
-60dB gain -62dB gain
(power-on default)
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Table Register 06H: Video Input Control
DESCRIPTION Input Sources Video COMMENTS TV_Y/CVBS_OUT ENC_Y/CVBS_IN ENC_Y_IN VCR_Y/CVBS_IN TV_Y/CVBS_IN used Mute Mute Mute (power-on default) TV_G_OUT Input Sources TV_G_OUT TV_B_OUT ENC_G_IN VCR_G_IN Mute Mute (power-on default) used Mute Mute Mute (power-on default) TV_B_OUT ENC_B_IN VCR_B_IN Mute Mute (power-on default) TV_R/C_OUT ENC_R/C_IN ENC_C_IN VCR_R/C_IN
Table Register 07H: Video Output Control
DESCRIPTION Slow Switching Fast Switching COMMENTS internal source Medium (4.5V 7V); external SCART source with 16:9 aspect ratio High impedance (power-on default) High 9.5V); external SCART source with aspect ratio GNDVID (power-on default) used Same level VCR_FB_IN VVID
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Table Register 08H: Video Input/Output Control
DESCRIPTION Input Sources Video R/C, inputs high-impedance bias application) COMMENTS VCR_Y/CVBS_OUT ENC_Y/CVBS_IN ENC_Y_IN VCR_Y/CVBS_IN TV_Y/CVBS_IN used Mute Mute Mute (power-on default) VCR_R/C_OUT ENC_R/C_IN ENC_C_IN VCR_R/C_IN Mute used Mute Mute Mute (power-on default)
ENC_R/C_IN Clamp/Bias
restore clamp active input (power-on default) Chrominance bias applied input High-impedance bias (power-on default) Biases R/C, inputs high impedance (overwrites ENC_R/C_IN clamp bias bit) restore clamp active input (power-on default) Chrominance bias applied input
VCR_R/C_IN Clamp/Bias
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Table Register 09H: Video Output Control
DESCRIPTION Function Switching COMMENTS internal source Medium (4.5V 7V); external SCART source with 16:9 aspect ratio High impedance (power-on default) High 9.5V); external SCART source with aspect ratio Normal operation; pulldown VCR_R/C_OUT (power-on default) Ground; pulldown VCR_R/C_OUT output amplifier driving VCR_R/C_OUT
VCR_R/C_OUT Ground
Table Register 0DH: Output Enable
DESCRIPTION TVOUT_FS Enable TV_Y/CVBS_OUT Enable TV_B_OUT Enable TV_G_OUT Enable TV_R/C_OUT Enable VCR_R/C_OUT Enable VCR_Y/CVBS_OUT Enable (power-on default) (power-on default) (power-on default) (power-on default) (power-on default) (power-on default) COMMENTS (power-on default)
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Table Register 10H: Operating Modes
DESCRIPTION Shutdown Standby mode (power-on default). Input video detection circuits active. Audio circuitry unless video detected. Once slow switch detected, signal paths between SCART connected. Full-power mode with input video detection video-load detection active. Full-power mode without input video detection video-load detection active. COMMENTS
Operating Mode
Table Register 0EH: Status
DESCRIPTION Slow-Switching Input Status Slow-Switching Input Status Power-On Reset COMMENTS internal source 4.5V external source with 16:9 aspect ratio used 9.5V 12.6V; external source with aspect ratio internal source 4.5V external source with 16:9 aspect ratio used 9.5V 12.6V; external source with aspect ratio VVID digital logic operate VVID high enough digital logic operate temperature below thermal shutdown limit
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Table Register 0Fh: Video Activity Status
DESCRIPTION CVBS Input Video Detection CVBS Output Load CVBS Input Video Detection CVBS Output Load ENC_Y/CVBS Input Video Detection ENC_Y_IN Input Video Detection COMMENTS video detected. Video detected. video detected. Video detected. video detected. Video detected. load connected. Load connected. video detected. Video detected. video detected. Video detected.
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Typical Application Circuit
0.1µF 3.3V 0.1µF 3.3V 0.1µF
VVID
VAUD TV_INL (MAX9671 ONLY)
7.68k
+3.3 CHIP TV_INR (MAX9671 ONLY)
2.55k 7.68k
2.55k MICROCONTROLLER DEV_ADDR TV_SS TV_B_OUT VIDEO ENCODER TV_G_OUT ENC_Y/CVBS_IN ENC_R/C_IN TVOUT_FS ENC_G_IN ENC_B_IN ENC_Y_IN ENC_C_IN TV_Y/CVBS_OUT 0.1µF TV_Y/CVBS_IN TV_R/C_OUT SCART TV_OUTL TV_OUTR
MAX9670 MAX9671
GNDVID VCR_OUTR 7.68k VCR_INR 2.55k
STEREO AUDIO DACS
VCR_OUTL 6.65k ENC_INL VCR_INL 2.55k VCR_SS 0.1µF 6.65k ENC_INR VCR_B_IN VCR_G_IN 0.1µF VCR_R/C_IN VCR_R/C_OUT VCRIN_FS 0.1µF SCART 7.68k
VALUES CS4334/5/8/9: 4.53k PCM1742: 5.57k
VCR_Y/CVBS_OUT 0.1µF CPVSS VCR_Y/CVBS_IN
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
Configurations
VCR_R/C_IN VCR_R/C_IN TV_G_OUT TV_G_OUT TV_B_OUT TV_B_OUT VCR_G_IN ENC_G_IN VCR_B_IN VCR_G_IN ENC_G_IN ENC_B_IN VCR_B_IN ENC_B_IN VCRIN_FS GNDVID GNDVID VIEW VVID VCRIN_FS
MAX9670/MAX9671
VIEW
ENC_C_IN ENC_R/C_IN TV_R/C_OUT VCR_R/C_OUT _Y/CVBS_OUT TV_Y/CVBS_OUT VCR_Y/CVBS_IN TV_Y/CVBS_IN ENC_Y_IN ENC_Y/CVBS_IN DEV_ADDR VAUD CPVSS ENC_INL ENC_INR
TVOUT_FS VCR_SS TV_SS TV_OUTR ENC_C_IN ENC_R/C_IN TV_R/C_OUT VCR_R/C_OUT VCR_Y/CVBS_OUT _Y/CVBS_OUT VCR_Y/CVBS_IN TV_Y/CVBS_IN ENC_Y_IN ENC_Y/CVBS_IN N.C.
VVID
N.C.
TVOUT_FS VCR_SS TV_SS TV_OUTR VCR_OUTR VCR_OUTL TV_OUTL VCR_INR VCR_INL TV_INR
MAX9670
VCR_OUTR VCR_OUTL TV_OUTL VCR_INR VCR_INL
MAX9671
ENC_INR
ENC_INL
DEV_ADDR
EXPOSED
TQFN
EXPOSED
TQFN
Chip Information
PROCESS: BiCMOS
TV_INL
VAUD
CPVSS
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Package Information
latest package outline information land patterns, www.maxim-ic.com/packages. PACKAGE TYPE TQFN TQFN PACKAGE CODE T4066+3 T4477+2 DOCUMENT 21-0141 21-0144
THIN.EPS
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors
Package Information (continued)
latest package outline information land patterns, www.maxim-ic.com/packages.
MAX9670/MAX9671
Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Connectors MAX9670/MAX9671
Package Information (continued)
latest package outline information land patterns, www.maxim-ic.com/packages.
Maxim cannot assume responsibility circuitry other than circuitry entirely embodied Maxim product. circuit patent licenses implied. Maxim reserves right change circuitry specifications without notice time.
_Maxim Integrated Products, Gabriel Drive, Sunnyvale, 94086 408-737-7600 2009 Maxim Integrated Products Maxim registered trademark Maxim Integrated Products, Inc.

Low-Power Audio/Video Switch with Audio Volume Control Dual SCART Conn

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