TC815 TC815 3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE
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3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTIONPOWER, BAND-GA VOLTAGE REFERENCE
TC815 TC815
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY HOLD FUNCTION
Auto-Range Operation Voltage Resistance Measurements User Selected AC/DC Current Ranges 20mA 200mA Operating Ranges DC/AC Voltage AC/DC Current Resistance Power Ohms Display HOLD Function Digit Resolution Auto-Range Mode 1/2000 Extended Resolution Manual Mode 1/3000 Memory Mode Relative Measurements F.S. Internal Conversion Triplex Drive Decimal Points, Digits Annunciators Continuity Detection Piezoelectric Transducer Driver Compact Surface Mounted 64-pin Plastic Flat Package Drift Internal Reference 75ppm/°C Battery Operation 10mW Battery Detection Annunciator
GENERAL DESCRIPTION
TC815 digit integrating analog-to-digital converter with triplex display drive automatic ranging. display hold function on-chip. Input voltage/ attenuators ranging from 1/10,000 automatically selected. Five full-scale ranges provided. CMOS TC815 contains logic analog switches needed manufacture auto-ranging instrument ohms voltage measurements. User selected 20mA 200mA current ranges available. Full-scale range decimal point annunciators automatically auto-range operation. Auto-range operation available during ohms (high power ohms) voltage measurements, eliminating expensive range switches hand-held designs. auto-range feature bypassed allowing decimal point selection input attenuator selection control through single line input. Expensive rotary switches required. During manual mode operation resolution extended 3000 counts full-scale. extended range operation indicated flashing MSD. extended resolution also available during 200k 2000V full-scale autorange operation. memory mode subtracts reading-up full-scale-from subsequent measurements. Typical applications involve probe resistance compensation resistance measurements, tolerance measurements, tare weight measurements. TC815 includes converter measurements. Only external diodes/resistors/capacitors required. complete annunciator describes TC815 meter function measurement range during ohms, voltage current operation. measurements indicated well auto-range operation. battery detection circuit also sets battery display annunciator. triplex display drive levels temperature compensation applied VDISP pin. With HOLD display updated. HOLD mode annunciator activated.
CONFIGURATION
DC/AC /LOW -MEM RANGE RBUF RVBUF
DGND
HOLD
ACVH
VSSA
XTAL1 XTAL2
ACVL
VDISP
TC815
k/m/ HOLD
BCP0 AGD0
-MEM/BATT
REFHI
ORDERING INFORMATION
Part TC815CBU Package 64-Pin PQFP Formed Leads Operating Temp. Range +70°C
REFH
AC/-/AUTO
ANALOG
TC815-1 11/14/96
TelCom Semiconductor reserves right make changes circuitry specifications devices.
RMREFH
RMREFL REFL
BCP1
ADG1
BCP2
AGD2
BCP3
VSSD
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTION TC815
"low ohms" measurement option allows circuit resistance measurements preventing semiconductor junctions from being forward biased. continuity buzzer output activated with inputs less than full scale. overrange input signal also enables buzzer, except during resistance measurements, flashes display. Featuring single battery operation, 10mW power consumption, precision internal voltage reference ppm/°C compact surface mounted 64-pin quad flat package, TC815 ideal portable instruments. Power Dissipation 70°C) Plastic Flat Package 1.14mW Operating Temperature Devices +70°C Storage Temperature -65°C +160°C Lead Temperature (Soldering, sec.) +300°C
*Stresses above those listed under Absolute Maximum Ratings cause permanent damage device. These stress ratings only functional operation device these other conditions above those indicated operational sections specifications implied. Exposure Absolute Maximum Rating Conditions extended periods affect device reliability.
ABSOLUTE MAXIMUM RATINGS*
Supply Voltage Analog Input Voltage Reference Input Voltage Voltage ±0.7V
ELECTRICAL CHARACTERISTICS: +25°C, unless otherwise specified, Figure Test Circuit.
Symbol Parameter
Zero Input Reading Input Resistor
Test Conditions
200mV Range 200mV Range w/10M Input 20mA 200mA Range 200mV Range Input Resistor 200mV Range w/10M Input 20mA 200mA Range Best Case Straight Line Error Error Excludes Range Measurements Excludes Range Measurement -VCOM)
-0000 -0001 -0000
0000 0000 2000
+0000 +0001 +0000 Count
Unit
Digital Reading
Rollover Error
Linearity Error Input Leakage Current Input Noice Frequency Response Open Circuit Voltage Open Circuit Voltage
Count µVp-p
VCOM VCTC
Analog Common Voltage Common Voltage Temperature Coefficient Display Multiplex Rate Logic Input
Logic Pull Current
20mA, HOLD Range, -MEM, OHMs (Relative DGND 20mA, HOLD Range, -MEM, OHMs (Relative DGND VSSA
Buzzer Drive Frequency Battery Flag Voltage Operating Supply Current
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTIONPOWER, BAND-GA VOLTAGE REFERENCE
DESCRIPTIONS
(64-Pin Plastic) Quad Flat Package Symbol 20mA XTAL1 XTAL2 VDISP k/m/HOLD BCP0 (Ones digit) ADG0 BCP1 AGD1 BCP2 AGD2 BCP3 AC/-/AUTO -MEM/BATT VSSD ANALOG RMREFH RMREFL CREFL CREFH REFHI
TC815
Description Logic Input. (Digital Ground) resistance measurement. Logic Input. (Digital Ground) 20mA full-scale current measurement. Audio frequency, kHz, output continuity indication during resistance measurement. noncontinuous signal output indicate input overrange during voltage current measurements. 32.768 Crystal Connection 32.768 Crystal Connection Sets peak drive signal: VDD-VDISP. VDISP also used compensate temperature variation crystal threshold voltage. Backplane Backplane Backplane Annunciator segment drive ohms resistance measurement current measurement. Annunciator segment drive resistance measurement voltage measurement. Annunciator segment drive ("kilo-ohms"), ("milli-amps" "milli-volts") HOLD mode. segment drive "b," segments decimal point least significant digit (LSD). segment drive "a," "g," segments LSD. segment drive segments LSD. segment drive "b," segments decimal point LSD. segment drive "a," "g," segments (Ten's digit). segment drive segments LSD. segment drive "b," segments decimal point (Hundreds digit). segment drive "a," "g," segments LSD. segment drive "b," segments decimal point LSD. segment drive "b," segments decimal point (Thousand's digit). annunciator drive signal measurements, polarity, auto-range operation. annunciator drive signal battery indication memory (relative measurement) mode. Negative battery supply connection internal digital circuits. Connect negative terminal battery. Positive battery supply connection Analog circuit ground reference point. Nominally 2.6V below VCC. Ratiometric (Resistance measurement) reference high voltage. Ratiometric (Resistance measurement) reference voltage. Reference capacitor negative terminal CREF Reference capacitor positive terminal CREF Reference voltage voltage current measurement. Nominally 163.85mV. Standard resistor connection full-scale. Standard resistor connection 2000 full-scale. Standard resistor connection full-scale range. Standard resistor connection 200k full-scale range. Standard resistor connection 2000k full-scale range. Voltage measurement attenuator. Voltage measurement attenuator.
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTION TC815
DESCRIPTIONS (Cont.)
(64-Pin Plastic) Quad Flat Package
Symbol ACVL RBUF RVIBUF ACVH VSSA DGND RANGE HOLD DC/AC
Description Voltage measurement 10,000 attenuator. Voltage measurement 1000 attenuator. Unknown voltage input attenuator. Unknown current input. output converter. Integrator capacitor connection. Nominally 0.1µf. (Low dielectric absorption. Polypropylene dielectrics suggested.) Auto-zero capacitor connection. Nominally 0.1µf. Unknown resistance input. Input filter connection. Negative input internal operational amplifier. Output internal operational amplifier. Active buffer output resistance measurement. Integration resistor connection. Integrator resistor nominally 220k. Active buffer output voltage current measurement. Integration resistor connection. Integration resistor nominally 150k. Positive output converter. Negative supply connection analog circuits. Connect negative terminal battery. Internal logic digital ground. logic level. Nominally 4.7V below VCC. Input manual operation change ranges. Input hold display. Connect GND. Input enter memory measurement mode relative measurements. LSD's stored subtracted from future measurements. Input that selects option during voltage/current measurements. resistance measurements, /LOW ohms power (voltage) ohms option selected. Input select current measurement. logic (Digital ground) current measurement.
BIAS
HOLD
TRI-PLEX DISPLAY
BIAS CONNECTED GND, PEAK DRIVE SIGNAL
AUTO
AUDIO TRANSDUCER ENABLE
0.1µF
XTAL1 XTAL2 VSSA VSSD DIGITAL
R7/100k
0.01
RMREFL 10,000) 1,000) 100) OHMS RANGE ATTENUATOR SEGMENT DECIMAL POINT DRIVE BACKPLANE DRIVERS VDISP LO/A
32.768 kHz) 39pf
OHMS INPUT
R8/220 (PTC)
R6/100k
R5/1.6385M
-MEM/ BCP3 AGD2 BCP2 AGD1 BCP1 AGD0 BCP0 HOLD BATT AC/-/AUTO DISPLAY 100's 10's ANNUNCIATORS 1000's
POSITIVE TEMPERATURE COEFFICIENT RESISTOR
R4/163.85k
R3/16.385k
R2/1638.5
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTIONPOWER, BAND-GA VOLTAGE REFERENCE
6.2V
R1/163.85
CURRENT INPUT
20mA
20mA 200mA
20mA
OHMS
Figure Typical Application Test Circuit
(÷1) (÷10) (÷100)
R21/2.2M R22/470k 4.7µf R23/10k R24/10k C5/1µf R26/3k RBUF R27/2k RVIBUF C4/µf C2/0.22µF C1/1µF
200mA
TC815 Digit Auto-Ranging with HOLD Function
20mA
200mA
VOLTAGE INPUT
R14/9.9M
500k
DC/AC /LOW
R12/1.11M
VOLTAGE RANGE ATTENUATOR
R11/101k
MANUAL RANGE CHANGE -MEM
R10/10k
(÷1,000) (÷10,000) ACVH
ACVL RBUF RVIBUF
0.1µF
HOLD
CINT 0.1µF
CREFL
RMREFH ANALOG CREFH REFHI
CREF 0.1µF 0.01µF
153.850mV R19/5k R18/24k
R9/1k
COMMON
*NOT REQUIRED WHEN RESISTOR NETWORK USED PAGE DETAILS.
TC815
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTION TC815
R7/100 OHMS INPUT R8/220 (PTC) 0.01 R4/163.85 R3/16385 6.2V CURRENT INPUT R15/9 1/10 1/100 1/10k AC-TO-DC CONVERTER OP-AMP R27/2 ACVL ADI52 RBUF RBUF BUFFER +DC) R20/100 R11/101 R10/10 R9/1 COMMON REFH CREFL REFH 1/10 1/100 1/1k 1/10k R2/1638.5 R1/163.85
TC815
R6/100 REFL R5/1.638 1/10k 1/1k 1/100 1/10 RMREFH
R18/24
2.8V
R19/5 ANALOG
163.85
R16/1
VOLTAGE INPUT R14/9.9
R13/500
REQUIRED
WHEN RESISTOR NETWORK USED. R12/1.11
0.01
0.22 ACVH C1/1
INT+
COMPARATOR INTEGRATOR 0.01 0.01
Figure TC815 Analog Section
DIGITAL SECTION
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTIONPOWER, BAND-GA VOLTAGE REFERENCE
RESISTANCE, VOLTAGE, CURRENT MEASUREMENT SELECTION
TC815 designed measure voltage, current, resistance. Auto-ranging available resistance voltage measurements. OHMS (Pin (Pin input controls normally pulled internally VCC. tying these pins Digital Ground (Pin 58), TC815 configured internally measure resistance, voltage, current. required signal combinations shown Table Table TC815 Measurement Selection Logic Function Select (Pin (Pin Digital Ground Floating Tied Notes: normally pulled internally high (Pin 28). This considered logic "1." Logic potential digital ground (Pin 58). Selected Measurement Voltage Resistance Current Voltage
TC815
standard resistance values listed Table Table Ohms Range Ladder Network Full-Scale Range Standard Resistance Power Ohms Mode
163.85 (R1) 2000 1638.5 (R2) 16,385 (R3) 200k 16385 (R4) 2,000k 1,638,500 (R5) available.
positive temperature coefficient resistor, 6.2V zener, Figure provide input voltage protection during ohms measurements.
RATIOMETRIC RESISTANCE MEASUREMENTS
TC815 measures resistance ratiometrically. Accuracy external standard resistors connected through low-power ohms mode selected full-scale range. power ohms mode limits voltage applied measured system. This allows accurate "in-circuit" measurements when resistor shunted semiconductor junctions. Full auto-ranging provided. External precision standard resistors automatically switched provide proper range. Figure shows detailed block diagram TC815 configured ratiometric resistance measurements. During signal integrate phase reference capacitor charges voltage inversely proportional measured resistance-RX. Figure shows conversion accuracy relies accuracy external standard resistors only. Normally required accuracy standard resistances will dictated accuracy specifications users product. Table gives equivalent ohms count various full-scale ranges allow users judge required resistor accuracy. Table Reference Resistors Full-Scale Range 200k 200k Reference Resistor 163.85 1638.5 16385 163850 1638500
RESISTANCE MEASUREMENTS OHMS POWER OHMS
TC815 configured reliably measure incircuit resistances shunted semiconductor junctions. TC815 power ohms measurement mode limits probe open circuit voltage. This prevents semiconductor junctions measured system from turning resistance measurement mode /LOW (Pin input selects power ohms measurement mode. power ohms measurements /LOW (Pin momentarily brought digital ground potential. TC815 sets power ohms measurement with maximum open circuit probe voltage 0.35V above analog common. power ohms mode display annunciator, LOW, will activated. power power ohms mode active. manual mode been selected, toggling will reset TC815 back auto-range mode. manual mode, decision make normal power ohms measurement should made before selecting desired range. power ohms measurement available full-scale range. Open circuit voltage this range below 2.8V.
/Count
1000
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTION TC815
VSSD R5/1638500 R4/163850 R3/16385 ÷10k ÷100 VOLTAGE REFERENCE -2.6V ANALOG COMMON OHMS VSSA
R2/1638.5
÷10k ÷100
~1.5 OHMS
R1/163.85
~1.5
REFHI
R6/100 R7/100 UNKNOWN
-2.8V
BUFFER
TC815
INTEGRATOR COMPARATOR
RVIBUF
Figure Ratiometric Resistance Measurement Functional Diagram
VOLTAGE MEASUREMENT
Resistive dividers automatically changed provide range readings 200mV 2000V full-scale readings (Figure input resistance external resistors R14/R13. divider resistors R9-R12. divider resistors give 200mV signal (Pin full-scale voltages from 200mV 2000V. applications which require input impedance divider network impedances lowered. This will reduce voltage offset errors induced switch leakage currents.
CURRENT MEASUREMENT
TC815 measures current only under manual range operation. user selectable full-scale ranges are: 20mA 200mA. Select current measurement mode holding input (Pin digital ground potential.
input (Pin left floating tied positive supply. ranges possible. 20mA full-scale range selected connecting 20mA input (Pin digital ground. left floating 200mA full-scale range selected. External current voltage conversion resistors used input (Pin 45). 20mA measurements resistor used. 200mA range needs resistor. Fullscale 200mV. board trace resistance between analog common (See Figure must minimized. 200mA range, example, 0.05 trace resistance will cause current voltage conversion error (Pin 45). extended resolution measurement option operates during current measurements. minimize rollover error potential difference between ANALOG COMMON (Pin system common must minimized.
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTIONPOWER, BAND-GA VOLTAGE REFERENCE
0.64 OHMS 0.32 OHMS
TC815
Example: 200k Full-Scale Measurement
163.85 163.85 0.64
16.385
CREF
0.64 163.85
UNKNOWN ANALOG BUFFER
"Ramp Voltage" "Ramp Down Voltage" RICI RICI
Where: Integrating Resistor, Integrate Time Integrating Capacitor, Deintegrate Time 163.85
Independent Internal Voltage Reference
Figure Resistance Measurement Accuracy External Standard Resistor
TC815
AUTO-ZERO PHASE
SIGNAL REFERENCE INTETRATE DEINTEGRATE PHASE PHASE NEXT CONVERSION AUTO-ZERO CYCLE EXTENDED RESOLUTION ZERO CROSSING
External Crystal 32.768kHz Internal Clock Period 2/32.768 61.04µsec Total Conversion Time TCONV 8000 (TP) 488.3msec CONV/SEC Integration Time 1638.5 (TP) 100.0msec Maximum Reference Deintegrate Time 3000 (TP) 183.1 (Manual, Extended Resolution) 2000 (TP) 122.1msec (Auto-Range)
MIN. AUTO-ZERO TIME 3361.5
FIXED 1638.5
3000.0 INPUT SIGNAL AUTO-RANGE OPERATION MAXIMUM 2000 MINIMUM AUTO-ZERO TIME 4361.5
TCONV 8000
Minimum Auto-Zero Time (8000-3000-1638.5) (TP) 205.1msec (Manual, Extended Resolution) (8000-2000-1638.5) (TP) 266.2msec (Auto-Range)
Figure Basic TC815 Conversion Timing
MEASUREMENT OPTIONS MEASUREMENTS
voltage current measurements TC815 configured measurements. chip operational amplifier external rectifier components perform conversion. When power first applied TC815 enters measurement mode. measurements (current voltage), AC/DC (Pin momentarily brought digital ground potential; TC815 sets-up measurements liquid crystal display annunciator activates. Toggling AC/DC again will return TC815 operation. manual operating mode been selected toggling AC/DC will reset TC815 back auto-range mode. manual mode operation operation should selected first then desired range selected.
minimum voltage full-scale voltage range full-scale minimum voltage 200mV. current measurements available 20mA 100mA full-scale current ranges.
CONVERSION TIMING
TC815 analog-to-digital converter uses conventional dual slope integrating conversion technique with added phase that automatically eliminates zero offset errors. TC815 gives zero reading with zero volt input. TC815 designed operate with 32.768 crystal. 32kHz crystal cost readily available; serves time base oscillator crystal many digital clocks. (See External Crystal Sources.) external clock divided two. internal clock frequency 16.348kHz giving clock period 61.04µsec. total conversion auto-zero phase, signal integrate
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTION TC815
reference deintegrate requires 8000 clock periods 488.3msec. There approximately complete conversions second. integration time fixed 1638.5 clock periods 100msec. This gives rejection 50/60Hz line noise. maximum reference deintegrate time, representing full-scale analog input, 3000 clock periods 183.1msec during manual extended resolution operation. 3000 counts available manual mode, extended resolution operation only. auto-ranging mode, maximum deintegrate time 2000 clock periods. 1000 clock periods added auto-zero phase. auto-ranging manual conversion takes 8000 clock periods. After zero crossing detected reference deintegrate mode, auto-zero phase entered. Figure shows basic TC815 timing relationships. control input. TC815 remains manual range mode until measurement function (voltage resistance) measurement option (AC/DC, /LO) changes. This causes TC815 return auto-ranging operation. "Auto" annunciator driver active only auto-range mode. Table shows typical operation where manual range selection option used. Also shown extended resolution display format.
EXTENDED RESOLUTION MANUAL OPERATION
TC815 extends resolution when operated manual range select mode current, voltage, resistance measurements. Resolution increases 3000 counts from 2000 counts. extended resolution feature operates only 2000k 2000V ranges during autorange operation. extended resolution operating mode readings above 1999 displayed with blinking most significant digit. blinking should interpreted digit three least significant digits display data normally. input overrange condition causes most significant digit blink sets three least significant digits display "000." buzzer output enabled input voltage current signals with readings greater than 2000 counts both manual auto-range operation. 18.2K RANGE DISPLAY "1"00.0 "1".000k 18.20k 2.35M RANGE 200k 2000k RANGE 2000k 200k 2000k 200k DISPLAY "1".000k "1"0.00k "1"00.0k "1"350k DISPLAY "1"350k "1".000k "1"0.00k "1"00.0k "1"350k "1".000k "1"0.00 "1"00.0k
MANUAL RANGE SELECTION
TC815 voltage resistance auto-ranging feature disabled momentarily bringing RANGE (Pin digital ground potential (Pin 58). When change from auto-to-manual ranging occurs first manual range selected last range auto-ranging mode. TC815 power-up circuit selects auto-range operation initially. Once manual range option entered, range changes made momentarily grounding RANGE Table Manual Range Operation VOLTS 23.5V RANGE DISPLAY POWER-ON 200mV "1"00.0mV AUTO-RANGE "1".000V OPERATION "1"0.00V 200V 23.5V RANGE CHANGES RANGE DISPLAY 200V 23.5V 200mV "1"00.0V 1.000V "1"3.50V 200V 23.5V 1000V 200mV "1"00.0mV "1".000V INPUT
VOLTS 18.2V RANGE DISPLAY "1".000V 18.20V
RANGE 200V 600V 200V
DISPLAY 18.20V "1".000V 18.20V 18.2V "1".000V 18.20V 18.2V
RANGE DISPLAY 18.20k "1"00.0 "1".000k 18.20k 200k 18.2k 2000k "1"00.0 "1".000k
Notes: flashing shown "1". flashing indicates TC815 over-ranging other digits zero first manual range selected last range auto-ranging mode. flashing with non-zero display indicates TC815 entered extended resolution operating mode. additional 1000 counts resolution available. This extended operation available only manual operation voltage, resistance current measurements. momentary ground connection.
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTIONPOWER, BAND-GA VOLTAGE REFERENCE
MANUAL RANGE SELECT CONTINUITY INDICATOR OUTPUT AUDIO FREQUENCY CONTINUOUS 4kHz BUZZER RX<19 RX>3000 RX>2000 DISPLAY TRUE READING MODE ALSO OPERATES WHEN AUTO-RANGING OPERATION SELECTED 2.999M YES* DISPLAY LAST DIGITS FLASH EXTENDED RESOLUTION FEATURE OVER-RANGE INDICATOR DISPLAY >FLASHING
TC815
TC815
OUTPUT NONCONTINUOUS AUDIO FREQUENCY OVER-RANGE INDICATOR
TC815
RANGE SELECT
VX>3000
DISPLAY >FLASHING
VX>2000
DISPLAY LAST DIGITS FLASH EXTENDED RESOLUTION FEATURE
DISPLAY TRUE READING
Figure Manual Range Selection; Resistance Measurements
Figure Manual Range Selection; Voltage Measurements
RANGE SELECT
TC815
OUTPUT AUDIO FREQUENCY
-MEM OPERATING MODE
Bringing (Pin momentarily configures TC815 "-MEM" operating mode. -MEM Annunciator becomes active. this operating mode subsequent measurements made relative last digits (99) displayed time low. This represents fullscale. last significant digits stored subtracted from following input conversions. examples clarify operation: Example Auto-Ranging 18.21 Range) Display 18.21 Store 0.21 (N+1) 19.87 Range) Display 19.87 0.21 19.66 (N+2) 22.65 (200 Range) Display 22.7 Disappears Example Fixed Range 200.0 Full-Scale 18.2 Display 18.2 Store (N+1) 36.7 Display 36.7 28.5 (N+2) Display -2.4* Will display minus resistance following input less than offset stored fixed range.
OVER-RANGE INDICATOR
IX>3000
DISPLAY >FLASHING
IX>2000
DISPLAY LAST DIGITS FLASH EXTENDED RESOLUTION FEATURE
DISPLAY TRUE READING
Figure Manual Range Selection; Current Measurements
resistance measurements buzzer signal does indicate overrange condition. buzzer used indicate continuity. Continuity defined resistance reading less than counts.
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTION TC815
Example Fixed Range 0.51 Display 0.51 Store 0.51 (N+1) 3.68V Display 3.68 0.51 3.17V (N+2) 0.23V Display 0.23 0.51 -0.28V (N+3) -5.21V Display 5.21 0.51 -5.72V power TC815 "-MEM" mode active. Once "-MEM" entered bringing again returns TC815 normal operation. "-MEM" mode also cancelled whenever measurement type (resistance, voltage, current AC/DC, range changed. -MEM annunciator will normal operation. auto-range operation following input signal cannot converted same range stored value, "-MEM" mode cancelled. annunciator turned off. "-MEM" operating mode very useful resistance measurements when lead length resistance would cause measurement errors. resistance automatic range selection procedure shown Figure range first range selected unless TC815 ohms resistance measurement option selected. ohms operation first fullscale range tried resistance range selected maximizes sensitivity. conversion results reading less than next most sensitive full-scale range tried. conversion less than auto-range operation continuous signal output (Pin
TC815
200.0mV FULL-SCALE RANGE 2,000V FULL-SCALE RANGE
(REMAINING RANGE SELECTED DURING CONVERSION)
CONVERSION
AUTOMATIC RANGE SELECTION OPERATION
When power first applied TC815 enters autorange operating state. auto-range mode entered from manual mode changing measurement function (resistance voltage) changing measurement option (AD/DC, automatic voltage range selection begins most sensitive scale first: 200mV 2.000V measurements. voltage range selection flow chart given Figure Internal input protection diodes (Pin VSSA (Pin clamp input voltage. external input resistance (See Figure R13) limits current safely overrange condition. voltage range selection designed maximize resolution. input signals less than full-scale (count reading <180) next most sensitive range selected. overrange voltage input condition flagged whenever internal count exceeds 2000 activating buzzer output (Pin This signal directly drive piezo electric acoustic transducer. range input signal causes signal 122msec, 122msec 610msec (See Figure 15). During voltage auto-range operation extended resolution feature operates 2000V range only (See extended resolution operating mode discussion).
(1/10N)
N=N-1
>2000
DISPLAY VOLTAGE (VX)
K=K+1
N=N+1
>3000
DISPLAY FLASH
ACTIVATE BUZZER OVER-RANGE
DISPLAY FLASH
START: POWER FUNCTION MEASUREMENT OPTION CHANGE
Figure Auto-Range Operation; Voltage Measurement
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTIONPOWER, BAND-GA VOLTAGE REFERENCE
TC815
200.0 FULL-SCALE RANGE 2,000k FULL-SCALE RANGE
TC815
overrange input does activate buzzer. range input conditions displayed blinking most significant digit with three least significant digits "000." extended resolution feature operates only 2000k 2000V full-scale range during auto-range operation. blinking most significant digit interpreted digit three least significant digits display data normally.
(REMAINING RANGE SELECTED DURING CONVERSION)
CONVERSION
BATTERY DETECTION CIRCUIT
(1/10N) CONTINUITY INDICATOR ACTIVATE BUZZER
N=N-1
CONTINUOUS 4kHz SIGNAL
TC815 contains battery detector. When battery supply been depleted nominal value display battery annunciator activated. battery detector shown Figure battery annunciator guaranteed remain with battery supply greater than 0.7V. annunciator guaranteed before supply battery reached 6.3V.
TRIPLEX LIQUID CRYSTAL DRIVE
K=K+1
>2000
DISPLAY RESISTANCE
N=N+1
OVER RANGE
>3000
DISPLAY FLASH
DISPLAY FLASH
EXTENDED RESOLUTION
START: POWER FUNCTION MEASUREMENT OPTION CHANGE
TC815 directly drives triplexed liquid crystal display (LCD) using bias drive. data, decimal point, polarity function annunciator drive signals developed TC815. direct connection triplex display possible without external drive electronics. Standard custom displays readily available from manufacturers. LCDs must driven with signal having zero component long display life. liquid crystal polarization function voltage appearing across backplane segment driver. peak drive signal applied VDISP.
Figure Auto-Range Operation; Resistance Measurement
BATTERY DETECTOR
TRIPLEX SEGMENT DRIVE LOGIC
COMPARATOR
VDISP PROPER WITH RESISTIVE DIVIDER VDISP
ANNUNCIATOR SELECTION LOGIC
TC815
6.2V VSSA 6.2V
TC815
VSSA VDISP "OFF" VP/3 "ON"
Figure Battery Detector
Figure Bias Drive
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTION TC815
VDISP, example, potential below peak drive signal VDISP "OFF" segment voltage Vp/3 across volt. "ON" segment 0.63Vp signal across 1.92V VCC-VDISP Since VDISP available, user adjust "ON" "OFF" levels various manufacturer's displays changing liquid crystal threshold voltage moves down with temperature. "OFF" segments become visible high operating temperatures. voltage with -20mV/°C temperature coefficient applied VDISP accommodate liquid crystal temperature operating characteristics necessary. TC815 internally generates intermediate drive potentials from resistive divider (Figure between (Pin VDISP (Pin ladder impedance approximately 150k. This drive method commonly known bias. With VDISP connected digital ground VP5.0V. intermediate levels needed that drive signals giving "ON" "OFF" levels generated. Figure shows typical drive signal resulting wave forms "ON" "OFF." voltage levels across selected element.
DISPLAYS
Although most users will design their custom display, several manufacturers offer standard displays TC815. Figure shows typical display available from Varitronix. Varitronix Ltd. Liven House, 61-63, King Street Kwun Tong, Hong Kong Tel: (852)2389-4317 Part No.: 310-1 Connector 310-2 Elastomer Connector OFFICE: Electronics/Varitronix 3250 Wilshire Blvd. Suite 1901 Angeles, 90010 Tel: (213) 738-8700 Adamant Kogyo Co., 16-7, Shinden, 1-Chome, Adachi-Ku, Tokyo, 123, Japan Tel: Tokyo 919-1171
BACKPLANES
SEGMENTS
APPLIED VOLTAGE
BP1) "ON"
(BCP BP1) "ON"
VRMS
VRMS
BACKPLANES
(BCP BP2) "ON"
VRMS
(3V)
PLANE
(AGD BP3) "ON"
VRMS
BP2) "OFF"
VRMS
BACK
BP1) "OFF"
VRMS
(AGD BP2) "ON"
VRMS
Waveforms Generate
Figure Triplex Drive Waveforms
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTIONPOWER, BAND-GA VOLTAGE REFERENCE
TC815
50.8 (+0.3-0.1) 45.0 VIEWING AREA MIN. 1.27 1.27 BETWEEN PADS 2.54 43.18 3.81
18.0 VIEWING AREA MIN.
10.0 MAX.
HOLD
22.86 (+0.3-0.1)
MAX.
AUTO
6.24
30.48 (+0.3-0.1)
3.81
DIMENSIONS (NOT SCALE)
Figure Typical Display Configuration TC815 Triplex
HOLD
-MEM
Auto
COM1 COM2 COM3
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTION TC815
DIGITAL GROUND CONVERSION SIGNAL
Non-Continuous Buzzer Signal Indicates Input Overrange
POWER 250mV 4000 8000 12000 CHANGE RANGE CHANGE RANGE CHANGE RANGE CHANGE INPUT 3.2V
1000 CLOCK PULSES INTEGRATE 1638.5 DEINTEGRATE AUTO-ZERO 122ms 2000 2500 3000
INTERNAL TC805 SIGNALS
AUTO-RANGING 200mVa RANGE OVERRANGE (PIN
,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,
MANUAL RANGE 2,000 RANGE IN-RANGE
,,,,,,, ,,,,,,, ,,,,,,, ,,,,,,, ,,,,,,, ,,,,,,, ,,,,,, ,,,,,, ,,,,,, ,,,,,, ,,,,,, ,,,,,, ,,,,,, ,,,,,, ,,,,,, ,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,
2,000 RANGE IN-RANGE
RANGE EXTENDED RANGE
2,000 RANGE IN-RANGE
2,000 RANGE OUT-OF-RANGE
CYCLE OVERRANGE BUZZER
MANUAL RANGE RANGE CHANGE CHANGE
RANGE CHANGE
BUZZER ACTIVATED PREVIOUS CONVERSION OVERRANGE
122ms 122ms 122ms
BUZZER ACTIVATED POWER
BUZZER ACTIVATED PREVIOUS CONVERSION OVERRANGE
Figure TC815 Timing Waveform Buzzer Output
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTIONPOWER, BAND-GA VOLTAGE REFERENCE
EXTERNAL CRYSTAL
TC815 designed operate with 32,768 crystal. This frequency internally divided give 61.04µsec clock period. conversion takes 8000 clock periods 488.3 msec conversions/second). Integration time 1638.5 clock periods 100msec. 32kHz quartz crystal readily available inexpensive. crystal commonly used digital clocks counters. Several crystal sources exist. partial listing Statek Corporation Main Orange, 92668 (714) 639-7810 TWX: 910-593-1355 TELEX: 67-8394 Daiwa Sinku Corporation 1389, shinzaike AZA-Kono Hirakacho, Kakogawa Hyogo, Japan Tel: 0794-26-3211 International Piezo 24-26, Shan Street Ton, Hong Kong TLX: 35454 XTAL Tel: 3-3501151
TC815
also activate buzzer output 15msec. range change during current measurement will activate buzzer output. Vendors piezo electric audio transducers are: Gulton Industries Piezo Products Division Durham Avenue Metuchen, Jersey 08840 (201) 548-2800 Typical P/Ns: 102-95NS, 101-FB-00 Taiyo Yuden (USA) Inc. Arlington Center West Algonquin Road Arlington Heights, Illinois 60005 Typical P/Ns: CB27BB, CB20BB, CB355BB
Display Decimal Point Selection
TC815 provides decimal point drive signal. decimal point position function selected fullscale range, shown Table Table Decimal Point Selection Full-Scale Range
2000V, 2000k 200V, 200.0k 20V, 20.00k 2.000k 200V, 200.0 200mV, 200.0 20mA 200mA
Contact manufacturer full specifications.
"BUZZER" DRIVE SIGNAL
TC815 output (Pin will drive piezo electric audio transducer. signal activated indicate input overrange condition current voltage measurements continuity during resistance measurements. During resistance measurement reading less than full-scale range causes continuous signal output. This used continuity indication. voltage current input measurement overrange indicated noncontinuous 4kHz signal output. display also flashes three least significant digits display zero. buzzer drive signal overrange shown Figure buzzer output active reading over 2000 counts both manual auto-range operation. buzzer activated during extended resolution measurement. signal swings from (Pin Digital Ground (Pin 58). signal when active. output also activated 15msec whenever range change made auto-range manual operation. Changing type measurement (voltage, current, resistance) measurement option (AC/DC, /LO) will
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTION TC815
AC-to-DC Converter Operational Amplifier
TC815 contains on-chip operational amplifier that connected rectifier AC-to-DC voltage current measurements. Typical operational amplifier characteristics are: Slew Rate: V/µsec Unity-Gain Bandwidth: Open-Loop Gain: 44dB Output Voltage Swing (Load ±1.5V (Referenced Analog Common) RBUF Selection (Pin ratiometric resistance measurements, signal (pin always positive with respect analog common. integrator swings negative. worst-case integrator swing range with manual, extended resolution option. input voltage, (pin easily calculated (Figure 16): VANCOM Potential Analog Common 2.7V 163.85 Internal switch resistance (VCC VANCOM)RX 0.63V
When measurement option selected, input buffer receives input signal through switch rather than switch (see Figure With external circuits, operating mode used perform other types functions within constraints internal operational amplifier. External circuits that perform true conversion peak hold function typical examples.
RBUF
Component Selection
Integration Resistor Selection TC815 automatically selects external integration resistors. RVBUF (pin selected voltage current measurement. RBUF (pin selected resistance measurements. RVBUF Selection (Pin auto-range operation, TC815 operates with maximum full-scale potential (pin 44). Resistive dividers (pin 41), (pin 40), (pin 43), (pin automatically switched maintain 200VV full-scale potential. manual mode, extended operating mode activated giving full-scale potential (pin 44). integrator output swing should maximized, saturations must avoided. integrator will swing within 0.45V (pin 0.5V (pin without saturating. swing suggested. value RVBUF easily calculated, assuming worst-case extended resolution input signal: VINT Integrator swing Integration time 100msec Integration capacitor 0.1µF VMAX Maximum input 300mV VMAX(TI) VINT (CI) 150k
3.1V integrator swing, value RBUF easily calculated: VINT Integrator swing 3.1V Integration time 100msec Integration capacitor 0.1µF 700mV MAX) (TI) 220k (VINT)
SW33
RBUF
163.85
RVBUF
ANALOG COMMON
Figure RBUF Calculation (200 Manual Operation)
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTIONPOWER, BAND-GA VOLTAGE REFERENCE
With battery voltage 6.6V, analog common will approximately 3.6V above negative supply terminal. With integrator swinging down from analog common toward negative supply, 3.1V swing will integrator output 0.5V above negative supply.
TC815
Flat Package Socket
Sockets suitable prototype work available. source Nepenthe Distribution 2471 East Bayshore, Suite Palo Alto, 94303 (415) 856-9332 TWX: 910-373-2060 "CBQ" Socket, Part IC51-064-042
Capacitors CINT, CREF
integration capacitor, CINT, must have dielectric absorption. 0.1µF polypropylene capacitor suggested. auto-zero capacitor, CAZ, reference capacitor, CREF, should selected leakage dielectric absorption. Polystyrene capacitors good choices.
Resistive Ladder Networks
Resistor attenuator networks voltage resistance measurements available from: Caddock Electronics 1717 Chicago Avenue Riverside, 92507 Tel: (714) 788-1700 TWX: 910-332-6108
Reference Voltage Adjustment
TC815 contains temperature drift internal voltage reference. analog common potential (pin established this reference. Maximum drift ppm/°C. Analog common designed approximately 2.6V below (pin 28). resistive divider (R18/R19, Functional Diagram) sets TC815 reference input voltage (REFHI, approximately 163.85mV. With input voltage near full scale 200mV range, adjusted proper reading.
Attenuator Accuracy
0.1% 0.25% 0.25%
Attenuator Type
Voltage Voltage Resistance
Caddock Part Number
1776-C441 1776-C44 T1794-204-1
Display Hold Feature
will updated when HOLD (pin connected (pin 58). Conversions made, display updated. HOLD mode annunciator activated when HOLD low. HOLD annunciator activated through triplex driver signal
3-1/2 DIGIT AUTO-RANGING CONVERTER WITH TRIPLEX DRIVE DISPLAY FUNCTION TC815
PACKAGE DIMENSIONS -Pin PQFP
MAX. .009 (0.23) .005 (0.13)
.018 (0.45) .012 (0.30)
.041 (1.03) .031 (0.78)
.555 (14.10) .547 (13.90) .687 (17.45) .667 (16.95)
.031 (.080) TYP.
.555 (14.10) .547 (13.90) .687 (17.45) .667 (16.95)
.010 (0.25) TYP. .120 (3.05) .100 (2.55) .130 (3.30) MAX.
Dimensions: (inches)
Sales Offices
TelCom Semiconductor 1300 Terra Bella Avenue P.O. 7267 Mountain View, 94039-7267 TEL: 650-968-9241 FAX: 650-967-1590 E-Mail: liter@c2smtp.telcom-semi.com TelCom Semiconductor Austin Product Center 9101 Burnet Suite Austin, 78758 TEL: 512-873-7100 FAX: 512-873-8236 TelCom Semiconductor H.K. Ltd. Chuk Street, Ground Floor Kong, Kowloon Hong Kong TEL: 852-2324-0122 FAX: 852-2354-9957
Printed U.S.A.
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