SC4612 Ver la hoja de datos (PDF) - Semtech Corporation

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componentes Descripción

Fabricante

SC4612

Wide Input Range High Performance Synchronous Buck Switching Controller

Semtech Corporation 

SC4612

POWER MANAGEMENT

Pin Descriptions

Pin # Pin#

MLPD SOIC

Pin Name Pin Function

1, 7

NC

No connection.

1

2

ILIM

The current limit programing resistors (R2 & R3) in conjunction with an internal current

source, program the current limit threshold for the low side MOSFET RDS-ON

sensing. Once the voltage drop across the Low side MOSFET is larger than the drop

across the programmed value, current limit condition occurs, and the hiccup current limit

protection is activated.

2

3

OSC

Oscillator Frequency set pin. An external capacitor to GND will program the oscillator

frequency. See Table "Frequency vs. COSC" on page 14 to determine oscillator

frequency.

3

4

SS/EN

Soft start pin. Internal current source connected to a single external capacitor will

determine the soft-start duration for the output. Inhibits the chip if pulled down.

TSS

≈

CSS X 1.2

ISS

4

5

5

8

EAO

FB

Error Amplifier output. A compensation network is connected from this pin to FB.

The inverting input of the error amplifier. Feedback pin is used to sense the output

voltage via a resistive divider.

6

6

VDD

Bias supply ranging from 4.5V to 28V, VDD pin is initially used to provide the base

drive to the internal pass transistor to regulate the DRV.

7

9

8

10

GND

DL

Ground.

DL signal (Drive Low). Gate drive for bottom MOSFET.

9

11

DRV

DRV supplies the output MOSFETs gate drive, and the chip analog circuitry. This pin

should be bypassed with a 2.2µF ceramic capacitor to GND. DRV is internally regulated

from the external supply connected to VDD. If VDD is below 10V , the supply could be

directly connected to the DRV pin.

10

12

11

13

BST

DH

BST signal. Supply for high side driver; can be directly connected to an external supply

or to a bootstrap circuit.

DH signal (Drive High). Gate drive for top MOSFET.

12

14

PHASE The return path for the high side gate drive, also used to sense the voltage at the phase

node for adaptive gate drive protection, and the low-side RDS-ON voltage sensing.

X

-

THERMAL Pad for heatsinking purposes. Connect to ground plane using multiple vias.

PAD (GND)

 2007 Semtech Corp.

7

www.semtech.com

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