SC185

© 2010 Semtech Corp.

Pin Descriptions

Pin #

Pin Name

Pin Function

1,2

PVIN

Input supply voltage for the converter power stage.

3

AGND

Ground connection for the internal circuitry. AGND needs to be connected to PGND directly.

4

AVIN

Power supply for the internal circuitry. AVIN is required to be connected to PVIN through an R-C filter of 1Ω

and 100nF.

5

MODE

MODE select pin. When connected to logic high, the device operates in forced PWM mode. When connected

to logic low, it operates normally with PSAVE mode at light load. The enable pin has a 500kΩ internal pull-

down resistor. This resistor is switched in circuit whenever the MODE pin is “Low” or when the part is in un-

dervoltage lockout.

6

EN

Enable pin. When connected to logic high or tied to AVIN pin, the SC185 is on. When connected to logic low,

the device enters shutdown and consumes less than 1µA current (typ.). The enable pin has a 500kΩ internal

pulldown resistor. This resistor is switched in circuit whenever the EN is“Low”or when the part is in undervolt-

age lockout.

7

PGOOD

Power good indicator. When the output voltage reaches the PGOOD threshold, this pin will be open-drain

(After the PGOOD delay), otherwise, it is pulled low internally.

8

NC

No connection.

9

SS

Soft Start. Connect a soft-start capacitor to program the soft start time. There is a 5µA charging current flow-

ing out of the pin.

10

VOUT

Output voltage sense pin.

11,12,13

PGND

Ground connection for converter power stage.

14,15,16

LX

Switching node - connect an inductor between this pin and the output capacitor.

T

Thermal Pad

Thermal pad for heatsinking purposes. Recommend to connect it to PGND. It is not connected internally.

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