AD7899SR-1

Overview

The AD7899SR-1 is a 14-bit successive-approximation analog-to-digital converter (ADC) from Analog Devices, designed for high-speed data acquisition. It operates on a single 5 V supply with typical power consumption of 80 mW and features a maximum throughput rate of 400 kSPS. The device includes an internal 2.5 V reference, track/hold amplifier, and on-chip clock oscillator. It supports input ranges of ±5 V and ±10 V with overvoltage protection up to ±18 V. The part utilizes a high-speed parallel interface compatible with 3 V or 5 V logic levels and is housed in a 28-lead SOIC package.

Feature Summary

• Integrated signal conditioning circuitry including a track/hold amplifier and internal 2.5 V reference source.
• High-speed parallel digital interface allowing direct connection to 3 V or 5 V microprocessors and DSPs.
• Robust analog input stage featuring overvoltage protection that prevents damage during voltage excursions beyond the selected range.

Applications

• High-performance multi-channel synchronous data acquisition systems for petroleum logging instruments.
• Industrial process control applications requiring fast conversion rates and wide dynamic input ranges.
• Portable instrumentation designs necessitating low-power operation from a single 5 V supply.

Procurement Notes

Verify the specific suffix 'SR-1' corresponds to the military temperature grade (-55°C to +125°C) and ±10 V/±5 V input range configuration. Confirm package type is Small Outline (SOIC). Ensure compatibility with system voltage requirements for VDD and VDRIVE pins before integration.

Selection Notes

Select this component when a 14-bit resolution and 400 kSPS throughput are required within a single-supply architecture. The AD7899SR-1 is suitable for environments demanding extended temperature stability. Consider the parallel interface complexity versus serial alternatives if pin count is constrained.

Part Context

The AD7899 series comprises three versions differentiated by input range: -1 for bipolar ±5 V/±10 V, -2 for unipolar 0 V to 2.5 V/5 V, and -3 for ±2.5 V. The 'S' suffix denotes the military-grade temperature range variant, while 'A' and 'B' denote commercial grades with varying accuracy specifications.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should evaluate other SAR ADCs with similar throughput and resolution if sourcing constraints exist.

FAQ

How is the conversion clock configured?

The AD7899SR-1 uses an internally laser-trimmed clock oscillator by default. An external clock can be applied to the CLKIN pin; if CLKIN is high on the rising edge of CONVST, the external clock is used.

What is the function of the STBY pin?

The STBY pin controls the standby mode. Driving this pin low places the device into a power-saving state with typical current consumption of 20 µA, while keeping it high enables normal operation.

Can the internal reference be overridden?

Yes. The VREF pin provides access to the internal 2.5 V reference but also allows an external precision 2.5 V reference to be connected, which will effectively overdrive the internal source.