SLASF96 April 2024 AFE20408
PRODUCTION DATA
The ADC can measure voltage and current on rails as high as 85V. Measure the current by sensing the voltage drop across an external shunt resistor at the SENSE+ and SENSE– pins. The voltage drop across the SENSE pins can be measured by the ADC using one of two full-scale range settings. Configure these settings by writing to the SHUNT_RANGE bit in the ADC_GEN_CFG register (located in the ADC configuration register page). The input stage of the ADC is designed such that the input common-mode voltage can be higher than the device supply voltage. The supported common-mode voltage range at the input pins is –0.3V to +85V, which makes the device an excellent choice for both high-side and low-side current measurements. There are no special considerations for power-supply sequencing because the common-mode input range and device supply voltage are independent of each other; therefore, the bus voltage can be present with the supply voltage off, and vice-versa without damaging the device.
The device also measures the bus supply voltage through the ADC pins and temperature through the integrated temperature sensor. The differential shunt voltage is measured between the SENSE+ and SENSE– pins, while the bus voltage is measured with respect to device ground. Monitored bus voltages can range from 0V to 85V, while monitored temperatures can range from –40°C to +125°C. Figure 6-4 shows how the shunt voltage, bus voltage, and temperature measurements are multiplexed internally to the ADCs.