Si9145

Vishay Siliconix

www.vishay.com

8

Document Number: 70021

S-40710—Rev. K, 19-Apr-04

PIN CONFIGURATIONS

13

MODE SELECT

OUTPUT

COMP

FB

NI

ENABLE

OTS

GND

SOIC-16

14

15

16

2

3

4

1

10

11

12

5

6

7

9

8

Top View

13

MODE SELECT

OUTPUT

COMP

FB

NI

ENABLE

OTS

GND

TSSOP-16

14

15

16

2

3

4

1

10

11

12

5

6

7

9

8

Top View

ORDERING INFORMATION−SOIC-16

Part Number

Temperature Range

Si9145BY-T1

25_ to 85_C

Si9145BY-T1—E3

−25_ to 85_C

ORDERING INFORMATION−TSSOP-16

Part Number

Temperature Range

Si9145BQ-T1

25_ to 85_C

Si9145BQ-T1—E3

−25_ to 85_C

PIN DESCRIPTION

The positive power supply for all functional blocks except

output driver. A bypass capacitor of 0.1 mF (minimum) is

recommended.

Pin 2: MODE SELECT

This pin is used to enable maximum duty cycle limit and set

The maximum duty cycle limit is usually used for forward,

flyback, and boost converters. The output polarity is high when

the PWM circuitry requires the external device to be turned on.

When connected to GND, the maximum duty cycle is not

limited (usually for buck converters driving a p-channel MOS).

The output polarity is low when the PWM circuitry requires the

external PMOS to be turned on.

(typical), the PWM circuitry can achieve 100% duty cycle. With

duty cycle is proportionally limited to this voltage.

The addition of external components can implement a soft

start function.

Pin 4: COMP

This pin is the output of the error amplifier. A compensation

network is connected from this pin to the FB pin to stabilize the

system. This pin drives one input of the internal pulse width

modulation comparator.

Pin 5: FB

The inverting input of the error amplifier. External resistors are

connected to this pin to set the regulated output voltage. The

compensation network is also connected to this pin.

Pin 6: NI

The non-inverting input of the error amplifier. In normal

This pin supplies 1.5 V trimmed to "1.5%. The reference

voltage is generated by a band-gap reference.

Pin 8: GND