AD7877 is a touch screen controller, providing 4-wire touch screen interface, LCD noise reduction function, automatic conversion sequencer and timer, user-programmable conversion parameters, on-chip temperature sensor, on-chip 2.5V reference, on-chip 8-bit DAC, 3 auxiliary analog inputs, 1 dedicated and 3 optional GPIOs, 2 direct battery measurement channels (0.5V to 5V), 3 interrupt outputs, touch pressure measurement, wake up on touch function, specified throughput rate of 125 kSPS, single supply, VCC of 2.7 V to 5.25 V, separate VDRIVE level for serial interface, shutdown mode: 1 μA maximum 32-lead, LFCSP, 5 mm×5 mm package 25-ball, WLCSP, 2.5 mm×2.8 mm package
The AD7877 is a 12‑bit successive‑approximation ADC designed for 4‑wire resistive touch‑screen interfaces. It includes on‑chip temperature sensing, battery measurement, an 8‑bit DAC, and a 2.5 V reference, making it suitable for portable devices such as PDAs, handhelds, and medical equipment.
The document provides a complete set of specifications, pin configurations, timing diagrams, absolute maximum ratings, and register descriptions, along with application notes on touch‑pressure, temperature, and battery monitoring.
| Resolution | 12 bits |
|---|---|
| Throughput rate | 125 kSPS |
| Supply voltage (Vcc) | 2.7 V to 3.6 V |
| On‑chip reference voltage | 2.5 V |
| Temperature range | ‑40 °C to +85 °C |
| Battery monitor input range | 0.5 V to 5 V |
| DAC resolution | 8 bits |
| Shutdown mode current | 1 µA |
The device can achieve a throughput rate of 125 kSPS.
It operates from a single supply voltage of 2.7 V to 3.6 V.
Yes, it has an internal 2.5 V reference.
The on‑chip temperature sensor works from –40 °C to +85 °C.