The AD7858/AD7858L are high-speed, low-power, 12-bit ADCs that operate from a single 3 V or 5 V power supply, the AD7858 being optimized for speed and the AD7858L for low power. They provide 8 single-ended or 4 pseudo-differential inputs, support 200 kSPS or 100 kSPS conversion rates, and feature an expandable serial interface. This product family is suitable for battery-powered systems, pen computers, instrumentation and control systems, and high-speed modems.
The AD7858 and AD7858L are single‑supply, 12‑bit analog‑to‑digital converters designed for battery‑powered and high‑speed applications. They feature automatic power‑up calibration, flexible serial interfaces (SPI, QSPI, 8051), and eight single‑ended or four pseudo‑differential input channels. Low power consumption (12 mW for AD7858, 4.5 mW for AD7858L at 3 V) and automatic power‑down options make them suitable for portable devices.
The datasheet provides detailed electrical specifications, timing diagrams, pin descriptions, and absolute maximum ratings. Key performance figures include up to 200 kSPS conversion rate, 70 dB minimum SNR, -78 dB THD, and 12‑bit resolution. The device operates from 3.0 V to 5.5 V supplies and includes built‑in reference and calibration circuitry.
| Supply Voltage (AVpp) | 3.0 V to 5.5 V |
|---|---|
| Maximum Sampling Rate | 200 kSPS (AD7858) / 100 kSPS (AD7858L) |
| Resolution | 12 bits |
| Power Consumption (Vpp = 3 V) | 12 mW (AD7858) / 4.5 mW (AD7858L) |
| Input Channels | Eight single‑ended or four pseudo‑differential |
| Signal‑to‑Noise Ratio (SNR) | ≥ 70 dB (min) |
| Total Harmonic Distortion (THD) | ≤ ‑78 dB |
| Input Leakage Current | ≤ 1 pA |
| Input Capacitance | 20 pF (typ) |
| Reference Input Voltage Range | 2.3 V/Vpp |
It operates from 3.0 V to 5.5 V supply voltage.
The AD7858 can sample at up to 200 kSPS, while the low‑power AD7858L reaches up to 100 kSPS.
It provides eight single‑ended inputs or four pseudo‑differential input pairs.
The AD7858L consumes about 4.5 mW at a 3 V supply.