The AD7581 is a microprocessor‑compatible 8‑bit, 8‑channel data‑acquisition system on a monolithic CMOS chip. It includes an 8‑bit successive‑approximation ADC, an 8 × 8 dual‑port RAM, three‑state data drivers and address latches, allowing direct interfacing to 8080, 8085, Z80, 6800 and similar processors. The device provides interleaved DMA, optional ratiometric operation, and fast conversion times.
The handbook provides detailed specifications (8‑bit resolution, 8‑channel, ±10 V input range, +5 V supply), timing diagrams, channel‑identification methods, calibration procedures for offset and gain, and mechanical data for the 28‑pin DIP packages. It also includes ordering information and recommended layout practices for reliable operation.
| Resolution | 8 bits |
|---|---|
| Number of channels | 8 channels |
| Digital output LOW voltage (maximum) | +0.4 V |
| Power supply voltage | +5 V |
| Guaranteed conversion time per channel | 66.6 µs @ 1.2 MHz clock |
| Package type | 28‑pin ceramic DIP (D‑28) or plastic DIP (N‑28) |
The AD7581 can interface directly to 8080, 8085, Z80, 6800 and other microprocessor systems.
A single channel conversion requires 80 clock pulses, so a complete scan of all eight channels needs 640 clock pulses.
The guaranteed conversion time is 66.6 µs per channel when the clock runs at 1.2 MHz.