Zero Reading for 0-V Input

Precision Null Detection With True Polarity

at Zero

1-pA Typical Input Current

True Differential Input

Multiplexed Binary-Coded-Decimal (BCD)

Output

Low Rollover Error: ±1 Count Max

Control Signals Allow Interfacing With

UARTs or Microprocessors

Autoranging Capability With Over-and

Under-Range Signals

TTL-Compatible Outputs

Second Source to Teledyne TSC7135,

Intersil ICL7135, Maxim ICL7135, and

Siliconix Si7135

CMOS Technology

DESCRIPTION

The ICL7135C and TLC7135C converters are manufactured with Texas Instruments highly efficient CMOS

technology. These 4 1/2-digit, dual-slope-integrating, analog-to-digital converters (ADCs) are designed to

provide interfaces to both a microprocessor and a visual display. The digit-drive outputs D1 through D4 and

multiplexed binary-coded-decimal outputs B1, B2, B4, and B8 provide an interface for LED or LCD

decoder/drivers as well as microprocessors.

The ICL7135C and TLC7135C offer 50-ppm (one part in 20,000) resolution with a maximum linearity error of

one count. The zero error is less than 10 μV and zero drift is less than 0.5 μV/°C. Source-impedance errors are

minimized by low input current (less than 10 pA). Rollover error is limited to ±1 count.

The BUSY, STROBE, RUN/HOLD, OVER RANGE, and UNDER RANGE control signals support

microprocessor-based measurement systems. The control signals also can support remote data acquisition

systems with data transfer through universal asynchronous receiver transmitters (UARTs).

The ICL7135C and TLC7135C are characterized for operation from 0°C to 70°C.