ADS7924, MicroPOWER™ Analog-to-Digital Converters

By Texas Instruments 41

ADS7924, MicroPOWER™ Analog-to-Digital Converters

Texas Instruments' ADS7924 is a four-channel, 12-bit analog-to-digital converter (ADC) with an I2C™ interface. With its low-power ADC core, support for low-supply operation, and a flexible measurement sequencer that essentially eliminates power consumption between conversions, the ADS7924 forms a complete monitoring system for power-critical applications such as battery-powered equipment and energy harvesting systems.

The ADS7924 features dedicated data registers and onboard programmable digital threshold comparators for each input. Alarm conditions can be programmed that generate an interrupt. The combination of data buffering, programmable threshold comparisons, and alarm interrupts minimize the host microcontroller time needed to supervise the ADS7924.

The four-channel input multiplexer (MUX) is routed through external pins to allow a common signal conditioning circuit to be used between the MUX and ADC, thereby reducing overall component count. The low-power ADC uses the analog supply as its reference and can acquire and convert signals in only 10 µs. An onboard oscillator eliminates the need to supply a master clock.

The ADS7924 is offered in a small, 3 mm x 3 mm QFN and is fully specified for operation over the industrial temperature range of -40°C to 85°C.

Features
  • Intelligent monitoring:
    • Auto-sequencing of 4-channel multiplexer
    • Individual alarm thresholds for each channel
    • Programmable scan rate
  • Wide supply range:
    • Analog supply: 2.2 V to 5.5 V
    • Digital supply: 1.65 V to 5.5 V
  • Small footprint: 3 mm x 3 mm QFN
  • Auto power-down control
  • MicroPOWER monitoring:
    • Four-channel scanning:
      • Every 1 ms → 25 µW
      • Every 10 ms → 5 µW
      • < 1 µA of power-down current
    • Programmable interrupt pin controls shutdown/wakeup of the microcontroller
    • PWRCON pin allows shutdown of external operational amplifiers

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