PM6675STR datasheet(6/53 Pages) STMICROELECTRONICS

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Pin settings

PM6675S

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2.2

Pin description

Table 2.

Pin functions

N°

Function

1LGND

LDO power ground. Connect to the 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 on page 30

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

µA. 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 on page 19 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 on page 30 for

details.

COMP

DC voltage error compensation input pin for the switching section. Refer to

Section 7.1.4: Mode-of-operation selection on page 30 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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