ST7538Q datasheet(39/44 Pages) STMICROELECTRONICS

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ST7538Q

Auxiliary analog and digital functions

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6.11

5V and 3.3V voltage regulators and power good function

ST7538Q has an embedded 5V linear regulator externally available to supply the application

circuitry.

The linear regulator has a very low quiescent current (50

µA) and a current capability of

50mA. The regulator is protected against short circuitry events.

The DVdd pin can act either as 3.3V Voltage Output or as Input Digital Supply. When the

DVdd pin is externally forced to 5V all the Digital I/Os operate at 5V, otherwise all the Digital

I/Os are internally supplied at 3.3V. The DVdd pin can also source 3.3V voltage to supply

external components. The 3.3V linear regulator has a very low quiescent current (50

µA) and

a current capability of 50mA. The regulator is protected against short circuitry events.

If AVdd and DVdd pins are connected to VDC pin, the 5V regulator maximum current

capability rises to 100mA

When the regulator Voltages are above of the power good thresholds VPG (see Table 4),

Power Good line is forced high, while is forced low at startup and when VDC or DVdd falls

below VPG - VPGHYS Voltage.

Figure 23. Power good function

PG OK

250mV

Time

VDC/DVDD

4.5V/3.125V

D03IN1411

ST7538Q Datasheet(PDF) 39 Page - STMicroelectronics