TC7135 Datasheet, PDF (1/22 Pages) TelCom Semiconductor, Inc – 4-1/2 DIGIT ANALOG-TO-DIGITAL CONVERTER

TC7135
4-1/2 Digit A/D Converter
Features
• Low Rollover Error: ±1 Count Max
• Nonlinearity Error: ±1 Count Max
• Reading for 0V Input
• True Polarity Indication at Zero for Null Detection
• Multiplexed BCD Data Output
• TTL-Compatible Outputs
• Differential Input
• Control Signals Permit Interface to UARTs and
Microprocessors
• Blinking Display Visually Indicates Overrange
Condition
• Low Input Current: 1pA
• Low Zero Reading Drift: 2µV/°C
• Auto-Ranging Supported with Overrange and
Underrange Signals
• Available in PDIP and Surface-Mount Packages
Applications
• Precision Analog Signal Processor
• Precision Sensor Interface
• High Accuracy DC Measurements
Device Selection Table
Part Number
TC7135CLI
TC7135CPI
TC7135CBU
Package
28-Pin PLCC
28-Pin PDIP
64-Pin PQFP
Temperature Range
0°C to +70°C
0°C to +70°C
0°C to +70°C
General Description
The TC7135 4-1/2 digit A/D converter (ADC) offers
50ppm (1 part in 20,000) resolution with a maximum
nonlinearity error of 1 count. An auto zero cycle
reduces zero error to below 10µV and zero drift to
0.5µV/°C. Source impedance errors are minimized by
a 10pA maximum input current. Rollover error is limited
to ±1 count.
Microprocessor based measurement systems are sup-
ported by BUSY, STROBE and RUN/HOLD control sig-
nals. Remote data acquisition systems with data
transfer via UARTs are also possible. The additional
control pins and multiplexed BCD outputs make the
TC7135 the ideal converter for display or
microprocessor based measurement systems.
Functional Block Diagram
SET V_REF = 1V ^–5V
TC7135
V_REF IN
100kΩ
Analog GND
0.47µF
1
2
V-
REF IN
UNDERRANGE
OVERRANGE
28
27
3 _ANALOG
26
COMMON ^STROBE
1µF
4
5
6
INT OUT ^RUN/HOLD
AZ IN ^{DIGTAL GND}
BUFF OUT POLARITY
25
24
23
Signal
Input
100kΩ
100
kΩ
7
1µF ₈
9
C_REF-
C_REF+
-INPUT
22
CLOCK IN
21
BUSY
(LSD) D1 ²⁰
0.1µF _{10 +INPUT}
+5V
11 _V+
19
D2
D3 ¹⁸
12 _{D5 (MSD)}
D4 ¹⁷
13 _{B1 (LSB) (MSB) B8} 16
14 _B2
B4 ¹⁵
Clock
Input
120kHz
© 2002 Microchip Technology Inc.
DS21460B-page 1