AD7877WACPZ-REEL7
Data acquisition IC - Touchscreen controller Analog Devices 12Bit 1x TSC input LFCSP-32-VQ
Product Details
The AD7877 is a 12-bit, successive approximation ADC with a synchronous serial interface and low on resistance switches for driving touch screens. The AD7877 operates from a single 2.7 V to 5.25 V power supply functional operation to 2.2 V, and features throughput rates of 125 kSPS. The AD7877 features direct battery measurement on two inputs, temperature and touch-pressure measurement.
The AD7877 also has an on-board reference of 2.5 V. When not in use, it can be shut down to conserve power. An external reference can also be applied and varied from 1 V to +VCC, with an analog input range of 0 V to VREF. The device includes a shutdown mode that reduces its current consumption to less than 1 μA.
To reduce the effects of noise from LCDs, the acquisition phase of the on-board ADC is controlled via the STOPACQ pin. User-programmable conversion controls include variable acquisition time and first conversion delay. Up to 16 averages can be taken per conversion. There is also an on-board DAC for LCD back-light or contrast control. The AD7877 runs in either slave or master mode using a conversion sequencer and timer. It is ideal for battery-powered systems such as personal digital assistants with resistive touch screens and other portable equipment.
The part is available in a 32-lead lead frame chip scale package LFCSP, and a 25-ball wafer level chip scale package WLCSP. AD7877W model is qualified for automotive applications.
**Applications**
- .
- Personal digital assistants
- .
- Smart hand-held devices
- .
- Touch screen monitors
- .
- Point-of-sale terminals
- .
- Medical devices
- .
- Cell phones
- .
- Pagers
### Features and Benefits
- .
- 4-wire touch screen interface
- .
- LCD noise reduction feature STOPACQ pin
- .
- Automatic conversion sequencer and timer
- .
- User-programmable conversion parameters
- .
- On-chip temperature sensor:
−40°C to +85°C
- .
- On-chip 2.5 V reference
- .
- On-chip 8-bit DAC
- .
- 3 auxiliary analog inputs
- .
- 1 dedicated and 3 optional GPIOs
- .
- 3 interrupt outputs
- .
- 2 direct battery measurement channels 0.5 V to 5 V
- .
- Qualified for automotive applications
- .
- See Data Sheet for additional features