PM6675AS datasheet(6/48 Pages) STMICROELECTRONICS

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Pin settings

PM6675AS

6/48

2.2

Pin description

Table 2.

Pin functions

N°

Function

LGND

LDO power ground. Connect to negative terminal of VTT output capacitor.

2LFB

LDO remote sensing. Connect as close as possible to the load via a low

noise PCB trace.

3NOSKIP

Pulse-skip/no-audible pulse-skip modes selector.

See Section 7.1.4: Mode-of-operation selection

4LPG

LDO section power-good signal (open drain output). High when LDO output

voltage is within ±10 % of nominal value.

5SGND

Ground Reference for analog circuitry, control logic and VTTREF buffer.

Connect together with the thermal pad and VTTGND to a low impedance

ground plane. See the Application Note for details.

6AVCC

+5 V supply for internal logic. Connect to +5 V rail through a simple RC

filtering network.

7VREF

High accuracy output voltage reference (1.237 V) for multilevel pins setting.

It can deliver up to 50 uA. Connect a 100 nF capacitor between VREF and

SGND in order to enhance noise rejection.

8VOSC

Frequency Selection. Connect to the central tap of a resistor divider to set

the desired switching frequency. The pin cannot be left floating. See

Section 7: Device description for details.

VSNS

Switching section output remote sensing and discharge path during output

soft-end. Connect as close as possible to the load via a low noise PCB

trace.

VSEL

Fixed output selector and feedback input for the switching controller.

If VSEL pin voltage is higher than 4 V, the fixed 1.5 V output is selected. If

VSEL pin voltage is lower than 4 V, it is used as negative input of the error

amplifier. See Section 7.1.4: Mode-of-operation selection for details.

COMP

DC voltage error compensation input pin for the switching section.

Refer to Mode of Operation Selection section for more details.

LILIM

Current limit selector for the LDO. Connect to SGND for ±1 A current limit or

to +5 V for ±2 A current limit.

SWEN

Switching Controller Enable. When tied to ground, the switching output is

turned off and a soft-end is performed.

LEN

Linear Regulator Enable. When tied to ground, the LDO output is turned off

and a soft-end is performed.

SPG

Switching Section power-good signal (open drain output). High when the

switching regulator output voltage is within ±10 % of nominal value.

PGND

Power ground for the switching section.

LGATE

Low-side gate driver output.

VCC

+5 V low-side gate driver supply. Bypass with a 100 nF capacitor to PGND.

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