PM6681ATR datasheet(7/47 Pages) STMICROELECTRONICS

7 / 47 page

PM6681A

Pin settings

7/47

LDO5

5 V internal regulator output. It can provide up to 100 mA peak current.

LDO5 pin supplies embedded low side gate drivers and an external load.

VIN

Device supply voltage input and battery voltage sense. A bypass filter

(4 W and 4.7

µF) between the battery and this pin is recommended.

CSENSE1

Positive current sense input for the switching section 1. This pin must be

connected through a resistor to the drain of the synchronous rectifier

(RDS(on) sensing) to obtain a positive current limit threshold for the power

supply controller.

PHASE1

Switch node connection and return path for the high side driver for the

section 1. It is also used as negative current sense input.

HGATE1

High-side gate driver output for section 1. This is the floating gate driver

output.

BOOT1

Bootstrap capacitor connection for the switching section 1. It supplies the

high-side gate driver.

SKIP

Pulse skipping mode control input.

– If the pin is connected to LDO5 the PWM mode is enabled.

– If the pin is connected to GND, the pulse skip mode is enabled.

– If the pin is connected to VREF the pulse skip mode is enabled but the

switching frequency is kept higher than 33 kHz

(No-audible pulse skip mode).

EN1

Enable input for the switching section 1.

– The section 1 is enabled applying a voltage greater than 2.4 V to this pin.

– The section 1 is disabled applying a voltage lower than 0.8 V.

when the section is disabled the high side gate driver goes low and low side

gate driver goes high.

PGOOD1

Power Good output signal for the section 1. This pin is an open drain output

and when the output of the switching section 1 is out of +/- 10 % of its

nominal value.It is pulled down.

PGOOD2

Power Good output signal for the section 2. This pin is an open drain output

and when the output of the switching section 2 is out of +/- 10 % of its

nominal value.It is pulled down.

FB1

Feedback input for the switching section 1. This pin is connected to a

resistive voltage-divider from OUT1 to PGND to adjust the output voltage

from 0.9 V to 5.5 V.

OUT1

Output voltage sense for the switching section 1.This pin must be directly

connected to the output voltage of the switching section.

COMP1

DC voltage error compensation pin for the switching section 1.

VCC

Device supply voltage pin. It supplies all the internal analog circuitry except

the gate drivers (see LDO5). Connect this pin to LDO5.

VREF

Internal 1.237 V high accuracy voltage reference. It can deliver 50

µA.

Bypass to SGND with a 100 nF capacitor to reduce noise.

Table 2.

Pin functions (continued)

N°

Function

PM6681ATR Datasheet(PDF) 7 Page - STMicroelectronics

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