AD779JD

Overview

The AD779JD is a 14-bit monolithic analog-to-digital converter featuring a sample-hold amplifier, microprocessor-compatible bus interface, onboard voltage reference, and clock generation circuitry. It operates from +5 V digital and ±12 V analog supplies with typical power consumption of 560 mW. The device provides a 1 MHz full power bandwidth and 500 kHz full linear bandwidth at a sampling rate of 128 kSPS. It supports unipolar (0 to +10 V) or bipolar (±5 V) input ranges with a 10 MΩ input impedance. Data is accessed via a 16-bit parallel bus in straight binary (unipolar) or two's complement (bipolar) format.

Feature Summary

• Complete integration of high-speed sample-hold amplifier, ADC, reference, and digital interface on a single chip.
• High input impedance allows direct connection to unbuffered sources without signal degradation.
• Factory trimming eliminates the need for external calibration modes or trimming to achieve rated performance.
• Monolithic BiMOS technology ensures long-term reliability compared to multichip designs.

Applications

• Signal processing applications requiring dynamic parameter characterization
• Multipurpose data acquisition systems
• Microprocessor-based measurement interfaces

Procurement Notes

Verify component authenticity through authorized Analog Devices distributors or certified secondary market suppliers. Request original manufacturer documentation and traceability records to confirm compliance with specifications. Inspect ceramic DIP packages for physical integrity and pin alignment prior to installation.

Selection Notes

Select the AD779JD when a 28-pin ceramic DIP package is required for the AC-characterized grade within the 0°C to +70°C temperature range. Choose this model over plastic DIP variants if hermetic sealing or specific thermal expansion matching is necessary for the application environment.

Part Context

The AD779JD belongs to the AD779 family of complete sampling ADCs fabricated on Analog Devices' BiMOS process. This family combines low-power CMOS logic with precision bipolar circuits and laser-trimmed thin-film resistors to achieve high speed and resolution.

Replacement Considerations

The AD779JN serves as a direct functional substitute using a plastic DIP package. For 8-bit bus compatibility, the AD679 series offers an alternative architecture with a different interface width.

FAQ

How does the AD779JD handle data output coding?

In unipolar mode, the output coding is straight binary. In bipolar mode, the output coding is two's complement binary.

What is the maximum throughput rate of the AD779JD?

The device supports a conversion rate of 128k conversions per second, with a conversion time of 6.3 μs and an aperture delay of 10 ns.

Can offset and gain errors be adjusted externally?

Yes, offset and gain errors can be trimmed out using external resistor networks connected to the BIPOFF and REFOUT pins as described in the application information section.