TC7126/A 3-1/2 Digit Analog-to-Digital Converters Features General Description Internal Reference with Low Temperature Drift The TC7126A is a 3-1/2 digit CMOS analog-to-digital converter (ADC) containing all the active components - TC7126: 80ppm/C Typical necessary to construct a 0.05% resolution measure- - TC7126A: 35ppm/C Typical ment system. Seven-segment decoders, digit and Zero Reading with Zero Input polarity drivers, voltage reference, and clock circuit are Low Noise: 15V P-P integrated on-chip. The TC7126A directly drives a liq- High Resolution: 0.05% uid crystal display (LCD), and includes a backplane driver. Low Input Leakage Current: 1pA Typ., 10pA Max. Precision Null Detectors with True Polarity at Zero A low cost, high resolution indicating meter requires only a display, four resistors, and four capacitors. The High-Impedance Differential Input TC7126A s extremely low power drain and 9V battery Convenient 9V Battery Operation with Low Power operation make it ideal for portable applications. Dissipation: 500 WTyp., 900 WMax. The TC7126A reduces linearity error to less than 1 Applications count. Rollover error (the difference in readings for equal magnitude, but opposite polarity input signals) is Thermometry below 1 count. High-impedance differential inputs Bridge Readouts: Strain Gauges, Load Cells, 12 offer 1pA leakage current and a 10 input imped- Null Detectors ance. The 15 V noise performance ensures arock P-P Digital Meters and Panel Meters: soli reading, and the auto-zero cycle ensures a zero - Voltage/Current/Ohms/Power, pH display reading with a 0V input. Digital Scales, Process Monitors The TC7126A features a precision, low drift internal voltage reference and is functionally identical to the Device Selection Table TC7126. A low drift external reference is not normally required with the TC7126A. Package Temperature Package Code Range CPL 40-Pin PDIP 0Cto+70C IPL 40-Pin PDIP (TC7126 Only) -25Cto+85C CKW 44-Pin PQFP 0Cto+70C CLW 44-Pin PLCC 0Cto+70C 2002 Microchip Technology Inc. DS21458B-page 1TC7126/A Package Type 44-Pin PLCC 44-Pin PQFP 6 543 2 1 44 43 42 41 40 44 43 42 41 40 39 38 37 36 35 34 NC 33 NC 1 F 7 39 V - REF 1 NC 2 32 G G C + 2 8 38 1 REF 31 C TEST 3 E 3 9 37 C - 1 REF ANALOG A OSC3 4 30 3 D 10 36 2 COMMON 29 G NC 5 3 35 V + TC7126CKW C 11 IN 2 TC7126CLW TC7126ACKW BP TC7126ACLW OSC2 6 28 NC 12 34 NC OSC1 7 27 POL B 13 33 V - 2 IN 26 AB V+ 8 4 A 14 32 2 C AZ D E 9 25 1 3 F 15 31 V 2 BUFF C 10 24 F 1 3 E 16 30 V 2 INT B B 11 23 1 3 D 17 29 V- 3 18 19 20 21 22 23 24 25 26 27 28 12 13 14 15 16 17 18 19 20 21 22 40-Pin PDIP (Normal) 44-Pin PDIP (Reverse) OSC1 V+ 1 40 OSC1 1 40 V+ Normal Pin Reverse Pin D D 2 39 OSC2 2 39 1 Configuration OSC2 Configuration 1 C C 3 38 OSC3 3 38 1 OSC3 1 B 4 4 B 37 TEST TEST 37 1 1 1 s A 5 36 V + 5 36 A V + REF 1 s 1 REF 1 V - F 6 35 6 35 F 1 V - REF 1 REF G C + G 7 34 C + 34 1 REF 7 1 REF TC7126CPL TC7126RCPL E C - C - E 8 33 REF 8 33 1 TC7126ACPL REF 1 TC7126ARCPL ANALOG ANALOG TC7126IPL 9 9 TC7126RIPL D 32 32 D 2 2 COMMON COMMON TC7126AIPL TC7126ARIPL 31 V + 31 C 10 V + 10 C 2 IN 2 IN V - B 11 30 V - 11 30 B IN 2 IN 2 10 s 10 s C A 12 29 C 12 29 A AZ 2 AZ 2 F V F 13 28 13 28 2 V BUFF 2 BUFF V E E 14 27 V INT 14 27 2 2 INT 26 26 D 15 V- V- 15 D 3 3 B 16 25 G 16 25 B G 3 2 3 2 100 s 100 s F 17 24 C 17 24 F C 3 3 3 3 100 s 100 s A E 18 23 A 18 23 E 3 3 3 3 G 1000 s AB 19 22 G 19 22 AB 1000 s 3 4 3 4 21 BP 20 21 POL 20 BP POL (Backplane) (Minus Sign) (Backplane) (Minus Sign) NC = No Internal Connection DS21458B-page 2 2002 Microchip Technology Inc. A B 1 3 F B 1 3 C E 3 1 AB D 4 1 V+ POL NC NC BP OSC1 G OSC2 3 A OSC3 3 C TEST 3 V + G REF 2 A V + REF 1 F V - 1 REF G C + REF 1 C - E 1 REF ANALOG D 2 COMMON C V + 2 IN V - B IN 2 C A 2 AZ V F BUFF 2 E V INT 2 D V- 3