The AD7870/AD7875/AD7876 are fast, complete, 12-bit analog-to-digital converters (ADCs) with features such as a 2 μs track-and-hold amplifier, 8 μs ADC, on-chip reference, laser-trimmed clock, and parallel, byte, and serial digital interfaces.
The document provides comprehensive technical specifications and application information for the AD7870/AD7875/AD7876 family of complete 12-bit analog-to-digital converters (ADCs). These devices integrate a track-and-hold amplifier, an 8 μs successive approximation ADC, a 3 V buried Zener reference, and versatile interface logic on a single chip. A key feature is the self-contained internal clock which is laser trimmed to guarantee accurate control of conversion time, eliminating the need for external clock timing components in most applications.
The datasheet details three distinct models tailored for different input ranges: the AD7870 accepts bipolar ±3 V inputs, the AD7875 handles unipolar 0 V to +5 V signals, and the AD7876 supports wider bipolar ±10 V ranges. All parts operate from ±5 V power supplies and can convert full-power signals up to 50 kHz. The document covers dynamic performance parameters such as signal-to-noise ratio and harmonic distortion for the AD7870 and AD7875, alongside DC accuracy specifications like integral nonlinearity and offset error.
| Resolution | 12 Bits |
|---|---|
| Signal-to-Noise Ratio (AD7870/AD7875) | 69 to 72 dB min |
| Total Harmonic Distortion | -80 to -78 dB max |
| Track-and-Hold Acquisition Time | 2 μs max |
| Input Voltage Range (AD7870) | ±3 V |
| Input Voltage Range (AD7875) | 0 to +5 V |
| Input Voltage Range (AD7876) | ±10 V |
| Power Supply Voltage | ±5 V nom |
No, the parts feature a self-contained internal clock which is laser trimmed to guarantee accurate control of conversion time.
The parts offer a choice of three data output formats: a single 12-bit parallel word, two 8-bit bytes, or serial data.
All parts can convert full power signals up to 50 kHz.