Features

• 12-Bit Binary (Plus Polarity and Over-Range) Dual

Slope Integrating Analog-to-Digital Converter

• Byte-Organized, TTL Compatible Three-State Outputs

and UART Handshake Mode for Simple Parallel or

Serial Interfacing to Microprocessor Systems

• RUN/HOLD Input and STATUS Output Can Be Used to

Monitor and Control Conversion Timing

• True Differential Input and Differential Reference

• Low Noise (Typ) . . . . . . . . . . . . . . . . . . . . . . . . 15μVP-P

• Input Current (Typ) . . . . . . . . . . . . . . . . . . . . . . . . . .1pA

• Operates At Up to 30 Conversions/s

• On-Chip Oscillator Operates with Inexpensive 3.58MHz

TV Crystal Giving 7.5 Conversions/s for 60Hz Rejection.

May Also Be Used with An RC Network Oscillator

for Other Clock Frequencies

Description

The ICL7109 is a high performance, CMOS, low power

integrating A/D converter designed to easily interface with

microprocessors.

The output data (12 bits, polarity and over-range) may be

directly accessed under control of two byte enable inputs and a

chip select input for a single parallel bus interface. A UART

handshake mode is provided to allow the ICL7109 to work with

industry-standard UARTs in providing serial data transmission.

The RUN/HOLD input and STATUS output allow monitoring

and control of conversion timing.

The ICL7109 provides the user with the high accuracy, low

noise, low drift versatility and economy of the dual-slope

integrating A/D converter. Features like true differential input

and reference, drift of less than 1μV/oC, maximum input bias

current of 10pA, and typical power consumption of 20mW

make the ICL7109 an attractive per-channel alternative to

analog multiplexing for many data acquisition applications.