300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Int
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19-1690 5/00
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference
MAX1082/MAX1083 10-bit analog-to-digital converters (ADCs) combine 4-channel analog-input multiplexer, high-bandwidth track/hold (T/H), serial interface with high conversion speed power consumption. MAX1082 operates from single +4.5V +5.5V supply; MAX1083 operates from single +2.7V +3.6V supply. Both devices' analog inputs software configurable unipolar/bipolar operation. 4-wire serial interface connects directly SPITM/QSPIand MICROWIREdevices without external logic. serial strobe output allows direct connection TMS320-family digital signal processors. MAX1082/ MAX1083 external serial-interface clock perform successiveapproximation analog-to-digital conversions. devices feature internal +2.5V reference reference-buffer amplifier with ±1.5% voltage-adjustment range. external reference with range also used. MAX1082/MAX1083 provide hard-wired SHDN four software-selectable power modes (normal operation, reduced power (REDP), fast power-down (FASTPD), full power-down (FULLPD)). These devices programmed shut down automatically conversion operate with reduced power. When using power-down modes, accessing serial interface automatically powers devices, quick turnon time allows them shut down between conversions. MAX1082/MAX1083 available 16-pin TSSOP packages.
Features
4-Channel Single-Ended 2-Channel Pseudo-Differential Inputs Internal Multiplexer Track/Hold Single-Supply Operation +4.5V +5.5V (MAX1082) +2.7V +3.6V (MAX1083) Internal +2.5V Reference 400kHz Sampling Rate (MAX1082) Power: 2.5mA (400ksps) 1.3mA (REDP) 0.9mA (FASTPD) (FULLPD) 4-Wire Serial Interface Software-Configurable Unipolar Bipolar Inputs 16-Pin TSSOP Package
MAX1082/MAX1083
Ordering Information
PART MAX1082ACUE MAX1082BCUE MAX1082AEUE TEMP. RANGE +70°C +70°C -40°C +85°C PINPACKAGE TSSOP TSSOP TSSOP (LSB) ±1/2 ±1/2
Ordering Information continued data sheet.
Applications
Portable Data Logging Data Acquisition Medical Instruments Battery-Powered Instruments Digitizers Process Control
VDD1 SHDN
Configuration
VIEW
VDD2 SCLK
MAX1082 MAX1083
SSTRB DOUT REFADJ
Typical Operating Circuit appears data sheet. QSPI trademarks Motorola, Inc. MICROWIRE trademark National Semiconductor Corp.
TSSOP
Maxim Integrated Products
free samples latest literature, visit www.maxim-ic.com phone 1-800-998-8800. small orders, phone 1-800-835-8769.
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
ABSOLUTE MAXIMUM RATINGS
VDD_ GND. -0.3V VDD_ VDD2 -0.3V +0.3V CH0-CH3, -0.3V (VDD 0.3V) REF, REFADJ -0.3V 0.3V) Digital Inputs -0.3V Digital Outputs GND. -0.3V (VDD 0.3V) Digital Output Sink Current .25mA Continuous Power Dissipation +70°C) 16-Pin TSSOP (derate 6.7mW/°C above +70°C) 533mW Operating Temperature Ranges MAX1082_C_E/MAX1083_CUE +70°C MAX1082_E_E/MAX1083_EUE -40°C +85°C Storage Temperature Range -60°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-MAX1082
(VDD1 VDD2 +4.5V +5.5V, GND, fOSC 6.4MHz, duty cycle, clocks/conversion cycle (400ksps), external +2.5V REF, REFADJ VDD1, TMIN TMAX, unless otherwise noted. Typical values +25°C.) PARAMETER ACCURACY (Note Resolution Relative Accuracy (Note Differential Nonlinearity Offset Error Gain Error (Note Gain-Error Temperature Coefficient Channel-to-Channel Offset-Error Matching ±1.6 ±0.2 MAX1082A MAX1083B missing codes over temperature ±0.5 ±1.0 ±1.0 ±3.0 ±3.0 bits ppm/°C SYMBOL CONDITIONS UNITS
DYNAMIC SPECIFICATIONS (100kHz sine-wave input, 2.5Vp-p, 400ksps, 6.4MHz clock, bipolar input mode) Signal-to-Noise plus Distortion Ratio Total Harmonic Distortion Spurious-Free Dynamic Range Intermodulation Distortion Channel-to-Channel Crosstalk (Note Full-Power Bandwidth Full-Linear Bandwidth CONVERSION RATE Conversion Time (Note Track/Hold Acquisition Time Aperture Delay Aperture Jitter Serial Clock Frequency Duty Cycle fSCLK tCONV tACQ SINAD SFDR fIN1 99kHz, fIN2 =102kHz 200kHz, 2.5Vp-p -3dB point SINAD 58dB harmonic
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
ELECTRICAL CHARACTERISTICS-MAX1082 (continued)
(VDD1 VDD2 +4.5V +5.5V, GND, fOSC 6.4MHz, duty cycle, clocks/conversion cycle (400ksps), external +2.5V REF, REFADJ VDD1, TMIN TMAX, unless otherwise noted. Typical values +25°C.) PARAMETER SYMBOL CONDITIONS Unipolar, VCOM VCH_ Bipolar, VCOM VCH_ VREF/2, referenced On/off leakage current, VCOM VCH_ VDD1 ±0.001 VREF +25°C 2.480 2.500 VREF output load 0.01 1.22 small adjustments, from 1.22V power down internal reference +2.05 VDD1 50mV VDD2 ISINK ISOURCE VDD2 VDD2 ±100 VDD1 0.05 2.520 VREF ±VREF/2 ppm/°C mV/mA UNITS ANALOG INPUTS (CH3-CH0, COM) Input Voltage Range, Single Ended Differential (Note Multiplexer Leakage Current Input Capacitance INTERNAL REFERENCE Output Voltage Short-Circuit Current Output Temperature Coefficient Load Regulation (Note Capacitive Bypass Capacitive Bypass REFADJ REFADJ Output Voltage REFADJ Input Range REFADJ Buffer Disable Threshold Buffer Voltage Gain EXTERNAL REFERENCE (reference buffer disabled, reference applied REF) Input Voltage Range (Note VREF 2.500V, fSCLK fMAX Input Current DIGITAL INPUTS (DIN, SCLK, SHDN) Input High Voltage Input Voltage Input Hysteresis Input Leakage Input Capacitance DIGITAL OUTPUTS (DOUT, SSTRB) Output Voltage Output Voltage High Three-State Leakage Current Three-State Output Capacitance COUT VINH VINL VHYST VREF 2.500V, fSCLK full power-down mode, fSCLK
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
ELECTRICAL CHARACTERISTICS-MAX1082 (continued)
(VDD1 VDD2 +4.5V +5.5V, GND, fOSC 6.4MHz, duty cycle, clocks/conversion cycle (400ksps), external +2.5V REF, REFADJ VDD1, TMIN TMAX, unless otherwise noted. Typical values +25°C.) PARAMETER POWER SUPPLY Positive Supply Voltage (Note VDD1, VDD2 Normal operating mode (Note Supply Current IVDD1 IVDD2 Power-Supply Rejection VDD1 VDD2 5.5V Reduced-power mode (Note Fast power-down mode (Note Full power-down mode (Note VDD1 VDD2 ±10%, midscale input ±0.5 ±2.0 SYMBOL CONDITIONS UNITS
ELECTRICAL CHARACTERISTICS-MAX1083
(VDD1 VDD2 +2.7V +3.6V, GND, fOSC 4.8MHz, duty cycle, clocks/conversion cycle (300ksps), external +2.5V REF, REFADJ VDD1, TMIN TMAX, unless otherwise noted. Typical values +25°C.) PARAMETER ACCURACY (Note Resolution Relative Accuracy (Note Differential Nonlinearity Offset Error Gain Error (Note Gain-Error Temperature Coefficient Channel-to-Channel Offset-Error Matching ±1.6 ±0.2 MAX1083A MAX1083B missing codes over temperature ±0.5 ±1.0 ±1.0 ±3.0 ±3.0 bits ppm/°C SYMBOL CONDITIONS UNITS
DYNAMIC SPECIFICATIONS (75kHz sine wave input, 2.5Vp-p, ksps, clock, bipolar input mode) Signal-to-Noise plus Distortion Ratio Total Harmonic Distortion Spurious-Free Dynamic Range Intermodulation Distortion Channel-to-Channel Crosstalk (Note Full-Power Bandwidth Full-Linear Bandwidth SINAD SFDR fIN1 73kHz, fIN2 =77kHz 150kHz, 2.5Vp-p -3dB point SINAD 58dB harmonic
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference
ELECTRICAL CHARACTERISTICS-MAX1083 (continued)
(VDD1 VDD2 +2.7V +3.6V, GND, fOSC 4.8MHz, duty cycle, clocks/conversion cycle (300ksps), external +2.5V REF, REFADJ VDD1, TMIN TMAX, unless otherwise noted. Typical values +25°C.) PARAMETER CONVERSION RATE Conversion Time (Note Track/Hold Acquisition Time Aperture Delay Aperture Jitter Serial Clock Frequency Duty Cycle ANALOG INPUTS (CH3-CH0, COM) Input Voltage Range, Single Ended Differential (Note Multiplexer Leakage Current Input Capacitance INTERNAL REFERENCE Output Voltage Short-Circuit Current Output Temperature Coefficient Load Regulation (Note Capacitive Bypass Capacitive Bypass REFADJ REFADJ Output Voltage REFADJ Input Range REFADJ Buffer Disable Threshold Buffer Voltage Gain EXTERNAL REFERENCE (reference buffer disabled, reference applied REF) Buffer Voltage Gain Input Voltage Range (Note VREF 2.500V, fSCLK fMAX Input Current DIGITAL INPUTS (DIN, SCLK, SHDN) Input High Voltage Input Voltage Input Hysteresis Input Leakage Input Capacitance VINH VINL VHYST VDD2 VREF 2.500V, fSCLK full power-down mode, fSCLK small adjustments, from 1.22V power down internal reference +2.05 2.05 VDD1 50mV VREF 0.75mA output load 0.01 1.22 ±100 VDD1 VREF +25°C 2.480 2.500 2.520 ppm/°C mV/mA Unipolar, VCOM VCH_ Bipolar, VCOM VCH_ VREF/2, referenced On/off leakage current, VCH_ VDD1 ±0.001 VREF ±VREF/2 fSCLK Normal operating mode tCONV tACQ Normal operating mode Normal operating mode SYMBOL CONDITIONS UNITS
MAX1082/MAX1083
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
ELECTRICAL CHARACTERISTICS-MAX1083 (continued)
(VDD1 VDD2 +2.7V +3.6V, GND, fOSC 4.8MHz, duty cycle, clocks/conversion cycle (300ksps), external +2.5V REF, REFADJ VDD1, TMIN TMAX, unless otherwise noted. Typical values +25°C.) PARAMETER Output Voltage Output Voltage High Three-State Leakage Current Three-State Output Capacitance POWER SUPPLY Positive Supply Voltage (Note VDD1, VDD2 Normal operating mode (Note Supply Current IVDD1 IVDD2 VDD1 VDD2 3.6V Reduced-power mode (Note Fast power-down mode (Note Full power-down mode (Note Power-Supply Rejection VDD1 VDD2 2.7V 3.6V, midscale input ±0.5 ±2.0 SYMBOL COUT ISINK ISOURCE 0.5mA VDD2 VDD2 VDD2 0.5V CONDITIONS UNITS DIGITAL OUTPUTS (DOUT, SSTRB)
TIMING CHARACTERISTICS-MAX1082
(Figures VDD1 VDD2 +4.5V +5.5V; TMIN TMAX; unless otherwise noted.) PARAMETER SCLK Period SCLK Pulse Width High SCLK Pulse Width SCLK Setup SCLK Hold Fall SCLK Rise Setup SCLK Rise Rise Hold SCLK Rise Fall Ignore Rise SCLK Rise Ignore SCLK Rise DOUT Hold SCLK Rise SSTRB Hold SCLK Rise DOUT Valid SCLK Rise SSTRB Valid Rise DOUT Disable Rise SSTRB Disable Fall DOUT Enable Fall SSTRB Enable Pulse Width High SYMBOL tCSS tCSH tCSO tCS1 tDOH tSTH tDOV tSTV tDOD tSTD tDOE tSTE tCSW CLOAD 20pF CLOAD 20pF CLOAD 20pF CLOAD 20pF CLOAD 20pF CLOAD 20pF CLOAD 20pF CLOAD 20pF CONDITIONS UNITS
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
TIMING CHARACTERISTICS-MAX1083
(Figures VDD1 VDD2 +2.7V +3.6V; TMIN TMAX; unless otherwise noted.) PARAMETER SCLK Period SCLK Pulse Width High SCLK Pulse Width SCLK Setup SCLK Hold Fall SCLK Rise Setup SCLK Rise Rise Hold SCLK Rise Fall ignore Rise SCLK Rise Ignore SCLK Rise DOUT Hold SCLK Rise SSTRB Hold SCLK Rise DOUT Valid SCLK Rise SSTRB Valid Rise DOUT Disable Rise SSTRB Disable Fall DOUT Enable Fall SSTRB Enable Pulse Width High SYMBOL tCSS tCSH tCSO tCS1 tDOH tSTH tDOV tSTV tDOD tSTD tDOE tSTE tCSW CLOAD 20pF CLOAD 20pF CLOAD 20pF CLOAD 20pF CLOAD 20pF CLOAD 20pF CLOAD 20pF CLOAD 20pF CONDITIONS UNITS
Note Tested VDD1 VDD2 VDD(MIN); GND, unipolar single-ended input mode. Note Relative accuracy deviation analog value code from theoretical value after full-scale range been calibrated. Note Offset nulled. Note Ground "on" channel; sine wave applied "off" channels. Note Conversion time defined number clock cycles multiplied clock period; clock duty cycle. Note common-mode range analog inputs (CH3-CH0 COM) from VDD1. Note External load should change during conversion specified accuracy. Note performance limited converter's noise floor, typically 300µVp-p. external reference below 2.5V compromises performance ADC. Note Electrical characteristics guaranteed from VDD1(MIN) VDD2(MIN) VDD1(MAX) VDD2(MAX). operations beyond this range, Typical Operating Characteristics. guaranteed specifications beyond limits, contact factory. Note midscale.Unipolar Mode. MAX1082 tested with 20pF DOUT, 20pF SSTRB, fSCLK 6.4MHz, MAX1083 tested with same loads, fSCLK 4.8MHz, Note SCLK GND. VDD1.
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
Typical Operating Characteristics
(MAX1082: VDD1 VDD2 5.0V, fSCLK 6.4MHz; MAX1083: VDD1 VDD2 3.0V, fSCLK 4.8MHz; CLOAD 20pF, 4.7µF capacitor REF, 0.01µF capacitor REFADJ, +25°C, unless otherwise noted.)
INTEGRAL NONLINEARITY DIGITAL OUTPUT CODE
MAX1080/1-01
DIFFERENTIAL NONLINEARITY DIGITAL OUTPUT CODE
MAX1080/1-02
SUPPLY CURRENT SUPPLY VOLTAGE (CONVERTING)
MAX1080/1-03
0.20 0.15 0.10 (LSB)
0.15 0.10 0.05 (LSB)
SUPPLY CURRENT (mA)
MAX1082 MAX1083
0.05
-0.05 -0.10 -0.15 1000 1000 DIGITAL OUTPUT CODE DIGITAL OUTPUT CODE
-0.05 -0.10
SUPPLY VOLTAGE
SUPPLY CURRENT TEMPERATURE
MAX1080/1-04
SUPPLY CURRENT SUPPLY VOLTAGE (STATIC)
MAX1080/1-05
SUPPLY CURRENT TEMPERATURE (STATIC)
MAX1080/1-06
SUPPLY CURRENT (mA) MAX1083 MAX1082
NORMAL OPERATION (PD1
MAX1082 (PD1 MAX1083 (PD1 MAX1082 (PD1 MAX1083 (PD1
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
REDP (PD1
FASTPD (PD1
MAX1082 (PD1 MAX1083 (PD1
TEMPERATURE (°C) SUPPLY VOLTAGE
TEMPERATURE (°C)
SHUTDOWN SUPPLY CURRENT SUPPLY VOLTAGE
MAX1080/1-07
SHUTDOWN SUPPLY CURRENT TEMPERATURE
MAX1080/1-08
REFERENCE VOLTAGE SUPPLY VOLTAGE
MAX1080/1-09
(PD1 SUPPLY CURRENT (µA)
(PD1 SUPPLY CURRENT (µA) MAX1082
2.5005
2.5003 REFERENCE VOLTAGE
MAX1083
2.5001
2.4999
2.4997
SUPPLY VOLTAGE
TEMPERATURE (°C)
2.4995 SUPPLY VOLTAGE
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference
Typical Operating Characteristics (continued)
(MAX1082: VDD1 VDD2 5.0V, fSCLK 6.4MHz; MAX1083: VDD1 VDD2 3.0V, fSCLK 4.8MHz; CLOAD 20pF, 4.7µF capacitor REF, 0.01µF capacitor REFADJ, +25°C, unless otherwise noted.)
REFERENCE VOLTAGE TEMPERATURE
MAX1080/1-10
MAX1082/MAX1083
OFFSET ERROR SUPPLY VOLTAGE
MAX1082/3-11
OFFSET ERROR TEMPERATURE
MAX1080/1-12
2.5002 2.5000 MAX1082 REFERENCE VOLTAGE 2.4998 2.4996 2.4994 2.4992 2.4990 2.4988 MAX1083
0.50
OFFSET ERROR (LSB)
OFFSET ERROR (LSB)
0.25
-0.25
-0.25 -0.50 -0.50 TEMPERATURE (°C) SUPPLY VOLTAGE TEMPERATURE (°C)
GAIN ERROR SUPPLY VOLTAGE
0.20 0.15 GAIN ERROR (LSB) 0.10 0.05 -0.05 -0.10 -0.15 -0.20 -0.25 SUPPLY VOLTAGE -.50
MAX1082/3-13
GAIN ERROR TEMPERATURE
MAX1080/1-14
0.25
GAIN ERROR (LSB)
-.25
TEMPERATURE (°C)
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
Description
NAME VDD1 CH0-CH3 SHDN Positive Supply Voltage Sampling Analog Inputs Ground Reference Analog Inputs. sets zero-code voltage single-ended mode. Must stable ±0.5LSB. Active-Low Shutdown Input. Pulling SHDN shuts down device, reducing supply current (typ). Reference-Buffer Output/ADC Reference Input. Reference voltage analog-to-digital conversion. internal reference mode, reference buffer provides 2.500V nominal output, externally adjustable REFADJ. external reference mode, disable internal buffer pulling REFADJ VDD1. Input Reference-Buffer Amplifier. disable reference-buffer amplifier, connect REFADJ DD1. Ground Serial-Data Output. Data clocked SCLK's rising edge. High impedance when high. Serial Strobe Output. SSTRB pulses high clock period before decision. High impedance when high. Serial-Data Input. Data clocked SCLK's rising edge. Active-Low Chip Select. Data will clocked into unless low. When high, DOUT SSTRB high impedance. Serial-Clock Input. Clocks data serial interface sets conversion speed. (Duty cycle must 60%.) Positive Supply Voltage FUNCTION
REFADJ DOUT SSTRB SCLK VDD2
VDD2
VDD2 DOUT CLOAD 20pF High-Z DOUT CLOAD 20pF High-Z
DOUT CLOAD 20pF High-Z
DOUT
CLOAD 20pF High-Z
Figure Load Circuits Enable Time
Figure Load Circuits Disable Time
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference
Detailed Description
MAX1082/MAX1083 ADCs successiveapproximation conversion technique input circuitry convert analog signal 10-bit digital output. flexible serial interface provides easy interface microprocessors (µPs). Figure shows functional diagram MAX1082/MAX1083. sinusoidal signal IN-, input voltage determined (VIN -)sin(2ft) maximum voltage variation determined (VIN 1LSB VREF CONV CONV
MAX1082/MAX1083
Pseudo-Differential Input
equivalent circuit Figure shows MAX1082/ MAX1083's input architecture, which composed T/H, input multiplexer, input comparator, switchedcapacitor DAC, reference. single-ended mode, positive input (IN+) connected selected input channel negative input (IN-) COM. differential mode, selected from following pairs: CH0/CH1 CH2/CH3. Configure channels according Tables MAX1082/MAX1083 input configuration pseudodifferential because only signal sampled. return side (IN-) connected sampling capacitor while converting must remain stable within ±0.5LSB (±0.1LSB best results) with respect during conversion. varying signal applied selected IN-, amplitude frequency must limited maintain accuracy. following equations express relationship between maximum signal amplitude frequency maintain ±0.5LSB accuracy. Assuming
2.6Vp-p, 60Hz signal will generate ±0.5LSB error when using +2.5V reference voltage 2.5µs conversion time fSCLK). When reference voltage used IN-, connect 0.1µF capacitor minimize noise input. During acquisition interval, channel selected positive input (IN+) charges capacitor CHOLD. acquisition interval spans three SCLK cycles ends falling SCLK edge after input control word's last been entered. acquisition interval, switch opens, retaining charge CHOLD sample signal IN+. conversion interval begins with input multiplexer switching CHOLD from IN-. This unbalances node ZERO comparator's input. capacitive adjusts during remainder conversion cycle restore node ZERO VDD1/2 within limits 10-bit resolution. This action equivalent transferring 12pF (VIN+ VIN-) charge from CHOLD binaryweighted capacitive DAC, which turn forms digital representation analog input signal.
SCLK SHDN
INPUT SHIFT REGISTER CLOCK CONTROL LOGIC OUTPUT SHIFT REGISTER ANALOG INPUT CLOCK 2-BIT 2.05 DOUT SSTRB
INPUT CAPACITIVE CHOLD 12pF ZERO CSWITCH* HOLD TRACK SAMPLING INSTANT, INPUT SWITCHES FROM SELECTED CHANNEL SELECTED CHANNEL. VDD1/2 SINGLE-ENDED MODE: CH0-CH3, COM. PSEUDO-DIFFERENTIAL MODE: SELECTED FROM PAIRS CH0/CH1 CH2/CH3. *INCLUDES INPUT PARASITICS COMPARATOR
+1.22V REFERENCE
VDD1 VDD2
REFADJ
+2.500V
MAX1282 MAX1283
Figure Functional Diagram
Figure Equivalent Input Circuit
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
Track/Hold
enters tracking mode falling clock edge after fifth 8-bit control word been shifted enters hold mode falling clock edge after eighth control word been shifted converter single-ended inputs, connected converter samples input. converter differential inputs, difference [(IN+) (IN-)] converted. conversion, positive input connects back CHOLD charges input signal. time required acquire input signal function quickly input capacitance charged. input signal's source impedance high, acquisition time lengthens, more time must allowed between conversions. acquisition time, tACQ, maximum time device takes acquire signal minimum time needed signal acquired. calculated following equation: tACQ RIN) 18pF where 800, source impedance input signal, never less than 400ns (MAX1082) 625ns (MAX1083). Note that source impedances below significantly affect ADC's performance. into MAX1082/MAX1083's internal shift register. After falls, first arriving logic defines control byte's MSB. Until this first "start" arrives, number logic bits clocked into with effect. Table shows control-byte format. MAX1082/MAX1083 compatible with SPI/ QSPI MICROWIRE devices. SPI, select correct clock polarity sampling edge control registers: CPOL CPHA MICROWIRE, SPI, QSPI transmit byte receive byte same time. Using Typical Operating Circuit, simplest software interface requires only three 8-bit transfers perform conversion (one 8-bit transfer configure ADC, more 8-bit transfers clock conversion result). Figure MAX1082/ MAX1083 QSPI connections. Simple Software Interface Make sure CPU's serial interface runs master mode generates serial clock. Choose clock frequency from 500kHz 6.4MHz (MAX1082) 4.8MHz (MAX1083). control byte call TB1. should format: 1XXXXXXX binary, where denote particular channel, selected conversion mode, power mode. general-purpose line pull low. Transmit and, simultaneously, receive byte call RB1. Ignore RB1. Transmit byte zeros ($00 hex) and, simultaneously, receive byte RB2. Transmit byte zeros ($00 hex) and, simultaneously, receive byte RB3. Pull high. Figure shows timing this sequence. Bytes contain result conversion, padded with three leading zeros, sub-LSB bits, trailing zero. total conversion time function serial-clock frequency amount idle time between 8-bit transfers. avoid excessive droop, make sure total conversion time does exceed 120µs. Digital Output unipolar input mode, output straight binary (Figure 13). bipolar input mode, output two's complement (Figure 14). Data clocked rising edge SCLK MSB-first format.
Input Bandwidth
ADC's input tracking circuitry 6MHz (MAX1082) 3MHz (MAX1083) small-signal bandwidth, possible digitize high-speed transient events measure periodic signals with bandwidths exceeding ADC's sampling rate using undersampling techniques. avoid high-frequency signals being aliased into frequency band interest, antialias filtering recommended.
Analog Input Protection
Internal protection diodes, which clamp analog input VDD1 GND, allow channel input pins swing from 0.3V 0.3V without damage. However, accurate conversions near full scale, inputs must exceed VDD1 more than 50mV lower than 50mV. analog input exceeds 50mV beyond supplies, allow input current exceed 2mA.
Start Conversion
Start conversion clocking control byte into DIN. With low, each rising edge SCLK clocks from
Table Channel Selection Single-Ended Mode (SGL
SEL2 SEL1 SEL0
MAX1082/MAX1083
Table Channel Selection Pseudo-Differential Mode (SGL
SEL2 SEL1 SEL0
Serial Clock
external clock only shifts data out, also drives analog-to-digital conversion steps. SSTRB pulses high clock period after last control byte. Successive-approximation decisions made appear DOUT each next SCLK falling edges, first (Figure SSTRB DOUT into high-impedance state when goes high; after next falling edge, SSTRB outputs logic low. Figure shows detailed serial-interface timings. conversion must complete 120µs less, droop sample-and-hold capacitors degrade conversion results.
fastest MAX1082/MAX1083 with held between conversions clocks conversion. Figure shows serial-interface timing necessary perform conversion every SCLK cycles. tied SCLK continuous, guarantee start first clocking zeros.
Applications Information
Power-On Reset
When power first applied, SHDN pulled low, internal power-on reset circuitry activates MAX1082/MAX1083 normal operating mode, ready convert with SSTRB low. After power supplies stabilize, internal reset time 10µs, conversions should performed during this phase. low, first logic interpreted start bit. Until conversion takes place, DOUT shifts zeros. Additionally, wait reference stabilize when using internal reference.
Data Framing
falling edge does start conversion. first logic high clocked into interpreted start defines first control byte. conversion starts SCLK's falling edge, after eighth control byte (the bit) clocked into DIN. start defined follows: first high clocked into with time converter idle; e.g., after VDD1 VDD2 applied. first high clocked into after conversion progress clocked onto DOUT (Figure Once start been recognized, current conversion only terminated pulling SHDN low.
Power Modes
Save power placing converter lowcurrent operating modes full power-down between conversions. Select power mode through control byte (Tables force converter into hardware shutdown driving SHDN GND. software power-down modes take effect after conversion completed; SHDN overrides software power mode immediately stops conversion progress. software power-down mode, serial interface remains active while waiting control byte start conversion switch full-power mode.
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
Table Control-Byte Format
(MSB) START 7(MSB) SEL2 NAME START SEL2 SEL1 SEL0 UNI/BIP SEL1 SEL0 UNI/BIP DESCRIPTION first logic after goes defines beginning control byte. These bits select which eight channels used conversion (Tables SGL/DIF (LSB)
unipolar, bipolar. Selects unipolar bipolar conversion mode. unipolar mode, analog input signal from VREF converted; bipolar mode, differential signal range from -VREF/2 +VREF/2. single ended, pseudo-differential. Selects single-ended pseudo-differential conversions. single-ended mode, input signal voltages referred COM. pseudo-differential mode, voltage difference between channels measured (Tables Select operating mode. Mode Full power-down Fast power-down Reduced power Normal operation
SGL/DIF
0(LSB)
Table Software-Controlled Power Modes
TOTAL SUPPLY CURRENT PD1/PD0 MODE Full Power-Down (FULLPD) Fast Power-Down (FASTPD) Reduced Power Mode (REDP) Normal Operating CONVERTING (mA) AFTER CONVERSION 0.9mA 1.3mA CIRCUIT SECTIONS* INPUT COMPARATOR Reduced Power Reduced Power Full Power REFERENCE
Circuit operation between conversions; during conversion circuits fully powered
Once conversion completed, device goes into programmed power mode until control byte written. power-up delay dependent power-down state. Software low-power modes will able start conversion immediately when running decreased clock rates (see Power-Down Sequencing). Upon power-on reset, when exiting software full power-down
mode, when exiting hardware shutdown, device goes immediately into full-power mode ready convert after when using external reference. When using internal reference, wait typical power-up delay from full power-down (software hardware) shown Figure
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
tACQ SCLK
UNI/ SGL/ START
SSTRB DOUT STATE IDLE 400ns (CLK 6.4MHz) CONVERSION IDLE
Figure Single-Conversion Timing
Software Power-Down Software power-down activated using bits control byte. When software power-down asserted, completes conversion progress powers down into specified low-quiescent-current state (2µA, 0.9mA, 1.3mA). first logic interpreted start puts MAX1082/MAX1083 into full-power mode. Following start bit, data input word control byte also determines next power-down state. example, word contains 0.9mA power-down resumes after conversion. Table details four power modes with corresponding supply current operating sections. Hardware Power-Down Pulling SHDN places converter hardware power-down. Unlike software power-down mode, conversion completed; stops coincidentally with SHDN being brought low. When returning normal operation-from SHDN, with external reference-the MAX1082/MAX1083 considered fully powered within actively pulling SHDN high. When using internal reference, conversion should initiated only when reference settled; recovery time dependent external bypass capacitors time between conversions.
Power-Down Sequencing
MAX1082/MAX1083 auto power-down modes save considerable power when operating less than maximum sample rates. Figures show average supply current function sampling rate. following sections discuss various powerdown sequences. Other combinations clock rates power-down modes attain lowest power consumption other applications. Using Full Power-Down Mode Full power-down mode (FULLPD) achieves lowest power consumption, 1000 conversions channel second. Figure shows MAX1083's power consumption one- four-channel conversions utilizing full power-down mode (PD1 with internal reference conversion controlled maximum clock speed. 0.01µF bypass capacitor REFADJ forms filter with internal reference resistor, with 170µs time constant. achieve full 10-bit accuracy, seven time constants 1.2ms required after power-up bypass capacitor fully discharged between conversions. Waiting this 1.2ms duration fast power-down (FASTPD) reducedpower (REDP) mode instead full power-up further reduce power consumption. This achieved using sequence shown Figure 11a. Figure shows MAX1083's power consumption one- four-channel conversions utilizing FULLPD
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
tCSW tCSS tCSO SCLK tDOH tDOV tDOE DOUT tSTH tSTV tDOD tCSH tCS1
tSTE SSTRB
tSTD
Figure Detailed Serial-Interface Timing
mode (PD1 with external reference conversion controlled maximum clock speed. dummy conversion power device needed, waiting time necessary start second conversion, thereby achieving lower power consumption half full sampling rate. Using Fast Power-Down Reduced Power Modes FASTPD REDP modes achieve lowest power consumption speeds close maximum sampling rate. Figure shows MAX1083's power consumption FASTPD mode (PD1 REDP mode (PD1 and, comparison, normal operating mode (PD1 figure shows power consumption using specified power-down mode, with internal reference conversion controlled maximum clock speed. clock speed FASTPD REDP should limited 4.8MHz MAX1082/MAX1083. FULLPD mode provide increased power savings applications where MAX1082/MAX1083 inactive long periods time, intermittent bursts high-speed conversions required.
Internal Reference MAX1082/MAX1083's full-scale range with internal reference 2.5V with unipolar inputs ±1.25V with bipolar inputs. internal reference voltage adjustable ±100mV with circuit Figure External Reference MAX1082/MAX1083's external reference placed input (REFADJ) output (REF) internal reference-buffer amplifier. REFADJ input impedance typically 17k. REF, input resistance minimum 18k. During conversion, external reference must deliver 350µA load current have less output impedance. reference higher output impedance noisy, bypass close with 4.7µF capacitor. direct input, disable internal buffer connecting REFADJ VDD1. Using REFADJ input makes buffering external reference unnecessary.
Transfer Function
Table shows full-scale voltage ranges unipolar bipolar modes. Figure depicts nominal, unipolar input/output (I/O) transfer function, Figure shows bipolar transfer function. Code transitions occur halfway between successive-integer values. Output coding binary, with 1LSB 2.44mV (2.500V/2/1024)
Internal External References
MAX1082/MAX1083 used with internal external reference voltage. external reference connected directly REFADJ pin. internal buffer designed provide 2.5V MAX1082/MAX1083. internally trimmed 1.22V reference buffered with 2.05 gain.
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
CONTROL BYTE
CONTROL BYTE
CONTROL BYTE
SCLK
DOUT
CONVERSION RESULT
CONVERSION RESULT
SSTRB
Figure Continuous 16-Clock/Conversion Timing
1.50 REFERENCE POWER-UP DELAY (ms) 1.25 1.00 0.75 0.50 0.25 0.0001 0.001 0.01 100k TIME SHUTDOWN SAMPLING RATE (sps) SUPPLY CURRENT (µA) 1000 CHANNELS CHANNEL
10,000 MAX1083, VDD1 3.0V CLOAD 20pF CODE 1010100000
Figure Reference Power-Up Delay Time Shutdown
Figure Average Supply Current Conversion Rate with External Reference FULLPD
1000 MAX1083, VDD1 VDD2 3.0V CLOAD 20pF CODE 1010100000 SUPPLY CURRENT (µA) SUPPLY CURRENT (mA)
NORMAL OPERATION REDP FASTPD
CHANNELS CHANNEL
MAX1083, VDD1 VDD2 3.0V CLOAD 20pF CODE 1010100000
SAMPLING RATE (sps)
SAMPLING RATE (sps)
Figure Average Supply Current Conversion Rate with Internal Reference FULLPD
Figure Average Supply Current Sampling Rate FASTPD, REDP, Normal Operation)
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
unipolar operation, 1LSB 2.44mV [(2.500V 1024] bipolar operation. capacitors close VDD1 MAX1082/MAX1083. Minimize capacitor lead lengths best supply-noise rejection. power supply very noisy, resistor connected lowpass filter (Figure 15).
Layout, Grounding, Bypassing
best performance, printed circuit (PC) boards; wire-wrap boards recommended. Board layout should ensure that digital analog signal lines separated from each other. analog digital (especially clock) lines parallel another, digital lines underneath package. Figure shows recommended system ground connections. Establish single-point analog ground (star ground point) GND. Connect other analog grounds star ground. Connect digital system ground this ground only this point. lowestnoise operation, ground return star ground's power supply should impedance short possible. High-frequency noise VDD1 power supply affect high-speed comparator ADC. Bypass supply star ground with 0.1µF 10µF
High-Speed Digital Interfacing with QSPI
MAX1082/MAX1083 interface with QSPI using circuit Figure (CPOL CPHA This QSPI circuit programmed conversion each four channels. result stored memory without taxing CPU, since QSPI incorporates microsequencer.
TMS320LC3x Interface
Figure shows application circuit interface MAX1082/MAX1083 TMS320 external clock mode. timing diagram this interface circuit shown Figure following steps initiate conversion MAX1082/MAX1083 read results: TMS320 should configured with CLKX (transmit clock) active-high output clock
WAIT 1.2ms
FULLPD
REDP
FULLPD
1.22V REFADJ 2.5V IVDD1 IVDD2 2.5mA
DUMMY CONVERSION 1.22V 0.01µF 2.5V 2.5mA 1.3mA 0.9mA 2.5mA
Figure 11a. Full Power-Down Timing
REDP
REDP
FASTPD
2.5V (ALWAYS 2.5mA 2.5mA 0.9mA 0.9mA 2.5mA 1.3mA
IVDD1 IVDD2
Figure 11b. FASTPD REDP Timing
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
+3.3V 510k 100k 0.047µF MAX1082 MAX1083 REFADJ
OUTPUT CODE VREF VCOM VCOM -VREF VCOM VREF 1024
1LSB
Figure MAX1082/MAX1083 Reference-Adjust Circuit
OUTPUT CODE FULL-SCALE TRANSITION
COM* INPUT VOLTAGE (LSB) *VCOM VREF VREF VCOM VCOM VREF 1024 1LSB
Figure Bipolar Transfer Function, Full Scale (FS) VREF VCOM, Zero Scale (ZS) VCOM
1LSB (COM) INPUT VOLTAGE (LSB) 3/2LSB
received from device. TMS320 reads data each next rising edges SCLK. These data bits represent 2-bit conversion result followed trailing bits, which should ignored. Pull high disable MAX1082/MAX1083 until next conversion initiated.
Definitions
Integral Nonlinearity
Integral nonlinearity (INL) deviation values from straight line actual transfer function. This straight line best-straight-line line drawn between endpoints transfer function, once offset gain errors have been nullified. static linearity parameters MAX1082/MAX1083 measured using best straight-line method.
Figure Unipolar Transfer Function, Full Scale (FS) VREF VCOM, Zero Scale (ZS) VCOM
CLKR (TMS320 receive clock) active-high input clock. CLKX CLKR TMS320 connected MAX1082/MAX1083's SCLK input. MAX1082/MAX1083's driven TMS320's port enable data clocked into MAX1082/MAX1083's pin. 8-bit word (1XXXXX11) should written MAX1082/MAX1083 initiate conversion place device into normal operating mode. Table select proper XXXXX values your specific application. MAX1082/MAX1083's SSTRB output monitored through TMS320's input. falling edge SSTRB output indicates that conversion progress data ready
Differential Nonlinearity
Differential nonlinearity (DNL) difference between actual step width ideal value 1LSB. error specification less than 1LSB guarantees missing codes monotonic transfer function.
Aperture Width
Aperture width (tAW) time circuit requires disconnect hold capacitor from input circuit (for instance, turn sampling bridge, unit hold mode).
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
Table Full Scale Zero Scale
UNIPOLAR MODE Full Scale VREF VCOM Zero Scale VCOM Positive Full Scale VREF VCOM BIPOLAR MODE Zero Scale VCOM Negative Full Scale -VREF VCOM
SUPPLIES
clock jitter, etc. Therefore, calculated taking ratio signal noise, which includes spectral components minus fundamental, first five harmonics, offset.
Signal-to-Noise Plus Distortion (SINAD)
SINAD ratio fundamental input frequency's amplitude equivalent other output signals: SINAD (dB) (SignalRMS NoiseRMS)
Effective Number Bits (ENOB)
VDD2 DGND
MAX1082 MAX1083
*OPTIONAL
DIGITAL CIRCUITRY
ENOB indicates global accuracy specific input frequency sampling rate. ideal ADC's error consists only quantization noise. With input range equal ADC's full-scale range, calculate ENOB follows: ENOB (SINAD 1.76) 6.02
Total Harmonic Distortion (THD)
ratio input signal's first five harmonics fundamental itself. This expressed where fundamental amplitude, through amplitudes 2nd- through 5th-order harmonics.
Figure Power-Supply Grounding Connection
Aperture Jitter
Aperture jitter (tAJ) sample-to-sample variation time between samples.
Aperture Delay
Aperture delay (tAD) time defined between rising edge sampling clock instant when actual sample taken.
Signal-to-Noise Ratio (SNR)
waveform perfectly reconstructed from digital samples, ratio full-scale analog input (RMS value) quantization error (residual error). ideal, theoretical minimum analog-to-digital noise caused only quantization error results directly from ADC's resolution bits): (6.02 1.76)dB reality, there other noise sources besides quantization noise, including thermal noise, reference noise,
Spurious-Free Dynamic Range (SFDR)
SFDR ratio amplitude fundamental (maximum signal component) value next-largest distortion component.
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
10µF 0.1µF
VDD1 VDD1 SHDN
VDD2
0.1µF 10µF (POWER SUPPLIES)
SCLK
ANALOG INPUTS
MAX1082 MAX1083
SSTRB
PCS0 MOSI
MC683XX
MISO
DOUT REFADJ
0.01µF (GND)
4.7µF
Figure QSPI Connections, External Reference
CLKX
SCLK
TMS320LC3x
CLKR
MAX1082 MAX1083
DOUT SSTRB
Figure MAX1082/MAX1083-to-TMS320 Serial Interface
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
SCLK START SEL2 SEL1 SEL0 UNI/BIP SGI/DIF HIGH IMPEDANCE HIGH IMPEDANCE
SSTRB DOUT
Figure MAX1082/MAX1083-to-TMS320 Serial Interface
Typical Operating
+2.5V ANALOG INPUTS VDD1 VDD2 0.1µF
Ordering Information (continued)
PART MAX1082BEUE MAX1083ACUE MAX1083BCUE MAX1083AEUE MAX1083BEUE TEMP. RANGE -40°C +85°C +70°C +70°C -40°C +85°C -40°C +85°C PINPACKAGE TSSOP TSSOP TSSOP TSSOP TSSOP (LSB) ±1/2 ±1/2
MAX1082 MAX1083
SCLK REFADJ DOUT SSTRB SHDN
4.7µF
Chip Information
TRANSISTOR COUNT: 4286 PROCESS: BiCMOS
(SK) MOSI (SO) MISO (SI)
0.01µF
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference
_Package Information
TSSOP.EPS
MAX1082/MAX1083
Note: MAX1082/MAX1083 have exposed pad.
300ksps/400ksps, Single-Supply, 4-Channel, Serial 10-Bit ADCs with Internal Reference MAX1082/MAX1083
NOTES
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 2000 Maxim Integrated Products Printed registered trademark Maxim Integrated Products.
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