AD7873 Datasheet

• 4-Wire touch screen interface
• On-chip temperature sensor: –40°C to +85°C
• On-chip 2.5 V reference
• Direct battery measurement (0 V to 6 V)
• Touch pressure measurement
• Specified throughput rate of 125 kSPS
• Single supply, V_CC of 2.2 V to 5.25 V
• Ratiometric conversion
• High speed serial interface
• Programmable
  8- or 12-bit resolution
• One auxiliary analog input
• Shutdown mode: 1 µA maximum
• 16-lead QSOP, TSSOP, and LFCSP packages

• Personal digital assistants
• Smart hand-held devices
• Touch screen monitors
• Point-of-sale terminals
• Pagers

The AD7873 is a 12-bit successive approximation ADC with a synchronous serial interface and low on resistance switches for driving touch screens. The AD7873 operates from a single 2.2 V to 5.25 V supply, with a throughput rate of 125 kSPS.

The AD7873 features direct battery measurement, temperature measurement, and touch pressure measurement. The AD7873 also has an on-board reference of 2.5 V that can be used for the auxiliary input, battery monitor, and temperature measurement modes. When not in use, the internal reference can be shut down to conserve power. An external reference can also be applied and varied from 1 V to V_CC with an analog input range from 0 V to V_REF. The device includes a shutdown mode that reduces the current consumption to less than 1 µA.

The AD7873 features on-board switches. This, coupled with low power and high speed operation, makes the device ideal for battery-powered systems with resistive touch screens. The part is available in a 16-lead, 0.15 inch quarter size outline package (QSOP), a 16-lead, thin shrink small outline package (TSSOP), and a 16-lead, lead frame chip scale package (LFCSP).