HI-774

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
- HI-774 (Max) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9µs
• Digital Error Correction (HI-774)
• 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


Application

• Military and Industrial Data Acquisition Systems
• Electronic Test and Scientific Instrumentation
• Process Control Systems


Pinout




Specifications

Supply Voltage
V_CC to Digital Common . . . . . . . . . . . . . . . . . . . . .  .  .  .  .  .  .  .  .  .  .  . . 0V to +16.5V
V_EE to Digital Common. . . . . . . . . . . . . . . . . . . . . . . . . . .  .  .  .  .  .  .  .  .  .0V to -16.5V
V_LOGIC to Digital Common. . . . . . . . . . . . . . . . . . . . . . . . .  .  . . .  .  .  .  .  .  .0V to +7V
Analog Common to Digital Common±1V
Control Inputs (CE, CS, AO, 12/8, R/C) to Digital Common . . .  .-0.5V to V_LOGIC +0.5V
Analog Inputs (REFIN, BIPOFF, 10VIN) to Analog Common. . . . . . . . . . . .  .  .  ±16.5V
20VIN to Analog Common . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  .  .  .  .  .  .  .  . ±24V
R_EFOUT . . . . .  .  .  .  .  .  .  .  Indefinite Short To Common, Momentary Short To . V_CC


Description

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 HI-X74(A) 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/674A) and 390mW (HI-774) at 12V. All HI-X74(A) models are available in sidebrazed DIP, PDIP, and CLCC. For additional HI-Rel screening including 160 hour burnin, specify "-8" suffix. For MIL-STD-883 compliant parts, request HI-574A/883, HI-674A/883, and HI-774/883 data sheets.