PIN FUNCTIONS

N

°

Name

Description

1

VSEN

Connected to the output voltage is able to manage overvoltage conditions and the PGOOD

signal.

2

OCSET

A resistor connected from this pin and the upper Mos Drain sets the current limit protection.

The internal 200

µA current generator sinks a current from the drain through the external

resistor. The overcurrent threshold is due to the following equation:

=

Rdson

3

SS

The soft start time is programmed connecting an external capacitor from this pin and GND.

The internal current generator forces through the capacitor 10

µA. This pin can be used to

disable the device forcing a voltage lower than 0.4V.

4 - 8

VID0 - 4

Voltage Identification code pins. These input are open collector and TTL compatible. Are used

to program the output voltage as specified in Table 1 and to set the overvoltage and

powergood thresholds.

9

COMP

This pin is connected to the error amplifier output and is used to compensate the voltage

control feedback loop.

10

FB

This pin is connected to the error amplifier inverting input and is used to compensate the

voltage control feedback loop.

11

GND

All internal voltage reference are referred to this pin.

12

PGOOD

This pin is an open collector output and is pulled low if the output voltage is not within

±10%

of the programmed voltage. This pin is forced high if the ”11111” VID is set.

13

PHASE

This pin is connected to the source of the upper mosfet and provides the return path for the

high side driver. This pin monitors the drop across the upper mosfet for the current limit.

14

UGATE

High side gate driver output.

15

BOOT

Bootstrap capacitor pin. Through this pin is supplied the high side driver and the upper mosfet.

16

PGND

Power ground pin. This pin has to be connected closely to the low side mosfet source in order

to reduce the noise injection into the device.

17

LGATE

This pin is the lower mosfet gate driver output.

18

VCC

Device supply voltage. The operative supply voltage range is 4.5V to 12V.

19

OVP

Over voltage protection. If the output voltage reach the 15% above the programmed voltage

this pin is driven high and can be used to drive an external SCR that crowbar the supply

voltage.

VSEN

OCSET

SS

VID0

VID1

VID3

VID2

VID4

COMP

PGOOD

PHASE

UGATE

PGND

BOOT

LGATE

VCC

OVP

RT

1

3

2

4

5

6

7

8

9

18

17

16

15

14

12

13

11

19

10

20

FB

GND

D98IN958

PIN CONNECTION

L6911B

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