AD7821 is a high performance 8-bit ADC with fast conversion time and wide bandwidth.
The AD7821 is a high‑speed, 8‑bit analog‑to‑digital converter fabricated in Analog Devices’ LC‑MOS process. It offers a fast conversion time of 660 ns, a 1 MHz maximum sampling rate, and a built‑in track‑and‑hold function that supports input signals up to 100 kHz.
The device operates from a single +5 V supply for unipolar inputs (0 V to +5 V) or from ±5 V supplies for bipolar inputs (‑2.5 V to +2.5 V). It provides standard microprocessor control signals, three‑state data outputs, an overflow output for cascading, and low power dissipation (≈50 mW).
| Resolution | 8 bits |
|---|---|
| Maximum Conversion Time | 660 ns |
| Maximum Sample Rate | 1 MHz |
| Unipolar Input Range | 0 V to +5 V |
| Bipolar Input Range | ‑2.5 V to +2.5 V |
| Power Dissipation | 50 mW typ |
| Slew Rate | 1.6 V/µs max |
| Total Unadjusted Error | ±1 LSB max |
| Signal‑to‑Noise Ratio (SNR) | 45 dB min |
| Total Harmonic Distortion (THD) | -50 dB max |
| Input Capacitance | 55 pF typ |
| Supply Current (CS=RD=0 V) | 20 mA max |
The AD7821 converts an input in a maximum of 660 ns.
It supports a unipolar range of 0 V to +5 V and a bipolar range of –2.5 V to +2.5 V.
Typical power dissipation is about 50 mW.
The device can sample up to 1 MHz.