The HI-X74(A) is a complete 12-bit, Analog-to-Digital

Converter, including a +10V reference clock, three-state

outputs and a digital interface for microprocessor control.

Successive approximation conversion is performed by two

monolithic dice housed in a 28 lead package. The bipolar

analog die features the Intersil Dielectric Isolation process,

which provides enhanced AC performance and freedom

from latch-up.

Custom design of each IC (bipolar analog and CMOS digital)

has yielded improved performance over existing versions of

this converter. The voltage comparator features high PSRR

plus a high speed current-mode latch, and provides precise

decisions down to 0.1 LSB of input overdrive. More than 2X

reduction in noise has been achieved by using current

instead of voltage for transmission of all signals between the

analog and digital ICs. Also, the clock oscillator is current

controlled for excellent stability over temperature.

The HI-X74(A) offers standard unipolar and bipolar input

ranges, laser trimmed for specified linearity, gain and offset

accuracy. The low noise buried zener reference circuit is

trimmed for minimum temperature coefficient.

Power requirements are +5V and ±12V to ±15V, with typical

dissipation of 385mW (HI-574A, HI-674A) at 12V.

Features

• Complete 12-Bit A/D Converter with Reference and Clock

• Full 8-Bit, 12-Bit or 16-Bit Microprocessor Bus Interface

• Bus Access Time . . . . . . . . . . . . . . . . . . . . . . . . . . . 150ns

• No Missing Codes Over Temperature

• Minimal Setup Time for Control Signals

• Fast Conversion Times

- HI-574A (Max) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25µs

- HI-674A (Max) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15µs

• Low Noise, via Current-Mode Signal Transmission

Between Chips

• Byte Enable/Short Cycle (AO Input)

- Guaranteed Break-Before-Make Action, Eliminating Bus

Contention During Read Operation. Latched by Start

Convert Input (To Set the Conversion Length)

• Supply Voltage . . . . . . . . . . . . . . . . . . . . . . ±12V to ±15V

• Pb-Free Available (RoHS Compliant)

Applications

• Military and Industrial Data Acquisition Systems

• Electronic Test and Scientific Instrumentation

• Process Control Systems