SC1146 查看數據表（PDF） - Semtech Corporation

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SC1146

VRM9.0 PROGRAMMABLE, MULTI-PHASE, HIGH PERFORMANCE PWM CONTROLLER

Semtech Corporation 

VRM9.0 PROGRAMMABLE, MULTI-PHASE,

HIGH PERFORMANCE PWM CONTROLLER

SC1146

July 25, 2000

PIN DESCRIPTION

Pin #

1

2

Pin Name

VCC 5V

Divsel

3

Clksel

4

Extclk

5

RREF

6

VID0(1)

7

VID1(1)

8

VID2(1)

9

VID3(1)

10

VID4(1)

11 OC+

12 OC-

13 COMP

14 FB

15

BGOUT

16 FBG

17 ENABLE

18 GND

19 DRV2

20 DRV0

21 VCC2

22 DRV1

23 DRV3

24 PWRGOOD

Pin Function

Supply voltage input (5V nominal)

Connect to Gnd for four phase operation and to logic High for three Phase

operation.

Clock Select: Logic High selects internal clock. Logic Low selects external

clock.

External Clock Input. The output frequency is determined by (Clock Input

Freq.)/4. Output freq.= (Clock Input)/4. Pull up to Vcc5v to select internal

clock.

Connects to external reference resistor. Sets the operating frequency of

the internal clock and the ramp time for the PWM. Reference voltage at

this pin is 2.05V. Trimmed to set 250µA at 8MHz.

Programming Input (LSB)

Programming Input

Programming Input

Programming Input

Programming Input (MSB)

Over current comparator. Non-Inverting input.

Over current comparator. Inverting input.

Compensation Pin. Compensation is acheived by connecting a capacitor in

series with a resistor between this pin and FBG. A 300K ohm resistor

must also be directly connected between this pin and FBG.

Feedback input connected to supply output.

Bandgap Reference Output. Output resistance = 3Kohm. Must be

bypassed with 4.7nF-100nF capacitor to FBG. This capacitor programs the

soft start time.

Feedback Ground. This pin must be connected to return side of output

caps. This pin is not internally connected to GND.

Connects to 5V to ENABLE. Connect to GND to disable entire device.

Ground Pin

Phase 2 output, output voltage range ~.3V - VCC2 - 1V.

Phase 0 output, output voltage range ~.3V - VCC2 - 1V.

Supply voltage for the DRV0-3, may be connected to +5V or +12V supply.

There is no Undervoltage Lockout on this pin.

Phase 1 output, output voltage range ~.3V - VCC2 - 1V.

Phase 3 output, output voltage range ~.3V - VCC2 - 1V.

Power good should be pulled-up to 5V supply via a 3K - 10K resistor.

NOTE: (1) All logic inputs and outputs are open collector TTL compatible.

The SC1146 is patent pending

© 2000 SEMTECH CORP.

4

652 MITCHELL ROAD NEWBURY PARK CA 91320

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