AD7875LP

Overview

The AD7875LP is a complete monolithic 12-bit analog-to-digital converter (ADC) utilizing LC2MOS technology. It integrates a track-and-hold amplifier, successive approximation ADC, and a laser-trimmed internal reference on a single chip. The device operates from ±5 V power supplies and accepts a unipolar analog input range of 0 V to +5 V. It supports parallel, byte, and serial digital interfaces with a typical data access time of 57 ns. The ADC achieves a sampling rate of 100 kSPS with a conversion time of 8 μs using an external clock or 6.5–9 μs with the internal clock. Dynamic performance includes a signal-to-noise ratio of 72 dB at 10 kHz input frequency.

Feature Summary

• Integrates a 2 μs track-and-hold amplifier, 12-bit SAR ADC, and 3 V buried Zener reference on a single die.
• Offers versatile interface logic supporting parallel, byte, and serial data output formats for microprocessor compatibility.
• Features a self-contained laser-trimmed internal clock that guarantees accurate conversion timing without external components.

Applications

• High-speed traditional measurement and control systems requiring multiplexed channels
• Digital signal processing applications needing fast bus access times
• Data acquisition systems utilizing modern 8-bit and 16-bit microprocessors

Procurement Notes

Verify the specific suffix 'LP' against the manufacturer's official ordering guide, as standard documentation primarily lists commercial (K, L), industrial (B, C), and extended (T) temperature grades in DIP or PLCC packages. Confirm package availability and lead times directly with Analog Devices or authorized distributors, as this specific suffix combination may indicate a specialized or legacy configuration not widely stocked.

Selection Notes

Select the AD7875 variant when a unipolar 0 V to +5 V input range is required, distinguishing it from the bipolar ±3 V (AD7870) or ±10 V (AD7876) models. Ensure the system design accommodates the ±5 V dual supply requirement. Verify that the 12-bit resolution and 100 kSPS throughput meet the application's dynamic performance needs, particularly regarding the 72 dB SNR specification at 10 kHz input frequencies.

Part Context

The AD7875 belongs to the AD7870/AD7875/AD7876 family of complete 12-bit sampling ADCs. These devices were designed to replace discrete solutions by combining the SHA, ADC, and reference into one IC. The AD7875 specifically targets unipolar applications within this family, sharing the same pinout and interface logic as its bipolar counterparts while differing only in input voltage scaling and offset characteristics.

Replacement Considerations

Direct functional replacements within the same family include the AD7870 for bipolar ±3 V inputs and the AD7876 for bipolar ±10 V inputs, provided the input range difference is acceptable. For upgraded performance, consider newer generations such as the AD768x series, though pin compatibility and interface logic may require schematic modifications.