SC2447 Просмотр технического описания (PDF) - Semtech Corporation

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SC2447

Dual-Phase, Single or Dual Output Synchronous Step-Down Controller

Semtech Corporation 

SC2447

POWER MANAGEMENT

Pin Descriptions

Pin

Pin Name Pin Function

1

CS1+ The Non-inverting Input of Channel 1 Current-sense Amplifier/Comparator

2

CS1-

The Inverting Input of Channel 1 Current-sense Amplifier/Comparator. Normally tied to the

output of the converter.

3

ROSC An external resistor connected from this pin to AGND sets the oscillator frequency.

4

IN1-

Inverting Input of Channel 1 Error Amplifier. Tie an external resistive divider between output

1 and ground for output voltage sensing.

5

COMP1 The Channel 1 Error Amplifier Output. This pin is used for loop compensation.

Edge-triggered Synchronization Input. When not synchronized, tie this pin to a voltage above

6

SYNC 1.5V or ground. An external clock (frequency > frequency set with ROSC) at this pin

synchronizes the controllers.

7

AGND Analog Signal Ground.

8

REF The Non-inverting Input of Channel 1 Error Amplifier.

9

REFOUT Buffered 0.5V internal reference.

10

REFIN

An external reference voltage is applied to this pin. This is also the non-inverting input of

Channel 2 Error amplifier.

11

COMP2 The Channel 2 Error Amplifier Output. This pin is used for loop compensation.

The Inverting Input of Channel 2 Error Amplifier. Tie an external resistive divider between

12

IN2- output 2 and ground for output voltage sensing. Tie to AVCC for two-phase single output

applications.

13

CS2-

The Inverting Input of Channel 2 Current-sense Amplifier/Comparator. Normally tied to the

output of the converter.

14

CS2+ The Non-inverting Input of Channel 2 Current-sense Amplifier/Comparator.

An external capacitor tied to this pin sets (1) the soft-start time (2) output overload shutdown

15

SS2/EN2 time for Channel 2. Pulling this pin below 0.6V tri-states GHD2 and forces GDL2 low. Leave

open for two-phase single output applications.

16

AVCC Power Supply Voltage for the Analog Portion of the Controllers.

20

GDH2 PWM Output 2.

21

GDL2 Logic Enable Signal for Channel 2.

24

GDL1 Logic Enable Signal for Channel 1.

25

GDH1 PWM Output 1.

28

SS1/EN1

An external capacitor tied to this pin sets (1) the soft-start time (2) output overload shutdown

time for Channel 1. Pulling this pin below 0.6V tri-states GDH1 and forces GDL1 low.

17,18,19

22,23,26,27

NC No Connection.

© 2006 Semtech Corp.

10

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