AD774BTD

Overview

The AD774BTD is a complete monolithic 12-bit successive-approximation analog-to-digital converter (ADC) manufactured by Analog Devices Inc. It integrates a high-precision voltage reference, clock generator, and three-state output buffers for direct microprocessor interfacing. The device operates on +5 V logic and ±12 V or ±15 V analog supplies, consuming approximately 175 mW to 375 mW. It supports unipolar (0 V–10 V, 0 V–20 V) and bipolar (±5 V, ±10 V) input ranges with industry-standard pinout compatibility to the AD574A. The T-grade variant is specified for operation from –55°C to +125°C in a hermetically sealed ceramic DIP package.

Feature Summary

• 8 µs maximum conversion time using successive-approximation architecture
• Integrated 10.00 V precision voltage reference with 1% max error
• Three-state digital outputs compatible with 8-bit and 16-bit microprocessor buses
• Four calibrated analog input ranges: 0 V–10 V, 0 V–20 V, ±5 V, and ±10 V

Applications

• Industrial process control systems requiring high-speed data acquisition
• Military instrumentation operating in extreme temperature environments
• Data acquisition modules for 8-bit and 16-bit microprocessor systems
• Precision measurement equipment utilizing standard ADC pinouts

Procurement Notes

Verify the specific grade suffix 'T' confirms the –55°C to +125°C military temperature range and hermetic ceramic packaging. Confirm that the datasheet revision matches the required specifications, as performance parameters such as linearity error may vary between J/K, A/B, and T grades. Ensure supply voltages align with the ±12 V/±15 V analog and +5 V logic requirements for proper functionality.

Selection Notes

Select the AD774BTD over the AD674B when an 8 µs conversion time is required instead of 15 µs. Choose this part if the application demands operation within the –55°C to +125°C temperature range, which necessitates the hermetically sealed ceramic DIP package. Verify that the system can accommodate the required three power supplies (+5 V, +12/+15 V, and –12/–15 V) and interface directly with the 12-bit parallel data bus.

Part Context

The AD774BTD belongs to the AD674B/AD774B family of 12-bit ADCs, designed as high-speed upgrades to the industry-standard AD574A. While pin-compatible with the AD574A, these devices offer faster conversion speeds and lower power consumption. The 'T' designation specifically identifies the military-grade version screened for extended temperature reliability and hermetic sealing, distinguishing it from commercial plastic packages.

Replacement Considerations

The AD674BTD serves as a slower alternative with identical pinout and functionality but features a 15 µs maximum conversion time. For applications requiring plastic packaging rather than hermetic ceramic, the AD774BAR (SOIC) or AD774BJN (DIP) are pin-compatible options, though they lack the extended military temperature rating.