3

NOTE: Pin designators: I = Input, O = Output, S = Supply

VID Input Pull up Current

3

5

7

µA

OTEN Input Pull up Current

3

5

7

µA

DC Electrical Specifications

(Continued)

PARAMETER

DESCRIPTION

CONDITION

MIN

TYP

MAX

UNIT

AC Electrical Specifications

PARAMETER

DESCRIPTION

CONDITIONS

MIN

TYP

MAX

UNIT

Nominal Oscillator Frequency

140

190

240

kHz

Clock Frequency

50

500

1000

kHz

Shutdown Delay

100

ns

Oscillator Sync. Pulse Width

Oscillator i/p (COSC) driven with

HCMOS gate

20

800

ns

Soft-start Period

us

Maximum Duty Cycle

97

%

Pin Descriptions

PIN NO.

PIN NAME

PIN TYPE

(NOTE 1)

FUNCTION

1

OTEN

I

Chip enable input, internal pull up (5mA typical). Active high.

2

CSLOPE

I

With a capacitor attached from CSLOPE to GND, generates the voltage ramp compensation for the PWM

3

COSC

I

4

REF

O

Band gap reference output. Decouple to GND with 0.1uF.

5

PWRGD

O

Power good, open drain output. Set low whenever the output voltage is not within ±13% of the programmed

value.

6

VID0

I

Bit 0 of the output voltage select DAC. Internal pull up sets input high when not driven.

7

VID1

I

Bit 1 of the output voltage select DAC. Internal pull up sets input high when not driven.

8

VID2

I

Bit 2 of the output voltage select DAC. Internal pull up sets input high when not driven.

9

VID3

I

Bit 3 of the output voltage select DAC. Internal pull up sets input high when not driven.

10

VID4

I

Bit 4 of the output voltage select DAC. Internal pull up sets input high when not driven.

11

FB

I

12

CS

I

Current sense. Current feedback input of PWM controller and over current capacitor input. Current limit

threshold set at +154mV with respect to FB. Connect sense resistor between CS and FB for normal

operation.

13

GND

S

Ground

14

GNDP

S

Power ground for low side FET driver. Tie to GND for normal operation.

15

LSD

O

Low side gate drive output.

16

VINP

S

Input supply voltage for low side FET driver. Tie to VIN for normal operation.

17

VIN

S

Input supply voltage for control unit.

18

LX

S

Negative supply input for high side FET driver.

19

HSD

O

High side gate drive output. Driver ground referenced to LX. Driver supply may be bootstrapped to enhance

low controller input voltage operation.

20

VH1

S

Positive supply input for high side FET driver.

EL7571