AD774BAR

Overview

The AD774BAR is a monolithic 12-bit successive-approximation analog-to-digital converter (ADC) from Analog Devices. It integrates a precision 10 V reference, clock generator, and three-state output buffers for direct microprocessor interfacing. The device supports unipolar ranges of 0–10 V and 0–20 V, as well as bipolar ranges of ±5 V and ±10 V. Operating on +5 V logic and ±12 V or ±15 V analog supplies, it achieves a maximum conversion time of 8 µs. The component is housed in a 28-lead plastic SOIC package and operates within an industrial temperature range of –40°C to +85°C.

Feature Summary

• Complete 12-bit SAR ADC with integrated 10 V reference and clock
• Industry-standard pinout compatible with AD574A
• Flexible digital interface supporting 8-bit or 12-bit data formats
• Four calibrated input ranges: 0–10 V, 0–20 V, ±5 V, and ±10 V

Applications

• High-speed upgrades for legacy AD574A systems
• Industrial process control instrumentation
• Data acquisition systems requiring direct microprocessor bus connection

Procurement Notes

Verify the specific grade suffix 'AR' corresponds to the required –40°C to +85°C operating temperature range and plastic SOIC packaging. Confirm that the internal reference calibration meets system accuracy requirements without external trimming. Ensure power supply decoupling adheres to datasheet recommendations to maintain 12-bit performance integrity.

Selection Notes

Select the AD774BAR over the AD674BAR variant when faster conversion speeds are necessary, as the AD774B offers an 8 µs maximum conversion time compared to 15 µs. Ensure the application utilizes single-ended inputs compatible with the specified unipolar or bipolar voltage spans. Verify that the driving source can maintain voltage stability during the dynamic load conditions inherent to SAR architectures.

Part Context

The AD774BAR belongs to the AD674B/AD774B family, which provides complete 12-bit A/D conversion solutions. These devices utilize Analog Devices’ BiMOS II process to combine high-performance bipolar analog circuitry with digital CMOS logic. The family is designed to replace older industry standard converters while offering improved speed and lower power consumption.

Replacement Considerations

The AD674BAR is a functional alternative within the same package but features a slower 15 µs conversion time. For higher resolution needs, the AD1674 offers sampling capabilities in a similar form factor.