ZHCSEJ3B June 2015 – April 2020 ADS131E08S
PRODUCTION DATA.
The ADS131E08S power-up time is set by the time required for the critical voltage nodes to settle to their final values. The analog supplies (AVDD and AVSS), digital supply (DVDD), and internal node voltages (VCAPx pins) must be up and stable when the data converter samples are taken to ensure performance. The combined current sourcing capability of the supplies and size of the bypass capacitors dictate the ramp rate of AVDD, AVSS, and DVDD. The VCAPx voltages are charged internally using the supply voltages. Table 23 lists the internal node voltages, their function, and recommended capacitor values to optimize the power-up time.
PIN | FUNCTION | RECOMMENDED CAPACITOR VALUE | |
---|---|---|---|
NAME | NO. | ||
VCAP1 | 28 | Band-gap voltage for the ADC | 470 pF to AVSS |
VCAP2 | 30 | Modulator common-mode | 270 nF to AVSS |
VCAP3 | 55 | PGA charge pump | 270 nF to AVSS |
VCAP4 | 26 | Reference common-mode | 270 nF to AVSS |
VREFP | 24 | Reference voltage after the internal buffer | 330 nF to AVSS |
AVDD | 19, 21, 22, 56, 59 | Analog supply | 1 µF each to AVSS |
AVDD1 | 54 | Internal PGA charge pump analog supply | 1 µF to AVSS1 |
AVSS | 20, 23, 32, 57, 58 | Analog supply | 1 µF each to AVDD |
AVSS1 | 53 | Internal PGA charge pump analog supply | 1 µF to AVDD1 |
DVDD | 48, 50 | Digital supply | 1 µF each to DGND |