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L6997D

STEP DOWN CONTROLLER FOR LOW VOLTAGE OPERATIONS

STMicroelectronics 

L6997

PIN FUNCTION (continued)

N°

Name

Description

8

VFB PWM comparator feedback input. Short this pin to INT pin when using the integrator function, or

to VSENSE pin without integrator.

9

OSC Connect this pin to the input voltage through a voltage divider in order to provide the feed-

forward function. It cannot be left floating.

10

SS Soft start pin. A 5µA constant current charges an external capacitor which value sets the soft-

start time.

11

ILIM An external resistor connected between this pin and GND sets the current limit threshold.

12

SHDN Shutdown. When connected to GND the device and the drivers are OFF. It cannot be left floating.

13

OVP Open drain output. During the over voltage condition it is pulled up by an external resistor.

14 PGOOD Open drain output. During the soft start and in case of output voltage fault it is low. It is pulled up

by external resistor.

15

PGND Low Side driver ground.

16

LGATE Low Side driver output.

17

VDR Low Side driver supply.

18

PHASE Return path of the High Side driver.

19

HGATE High side MOSFETS driver output.

20

BOOT Bootstrap capacitor pin. High Side driver is supplied through this pin.

ELECTRICAL CHARACTERISTICS

(VCC = VDR = 3.3V; Tamb = 0°C to 85°C unless otherwise specified)

Symbol

Parameter

Test Condition

SUPPLY SECTION

Vin Input voltage range

Vout=Vref Fsw=110Khz Iout=1A

VCC,

VDR

VCC Turn-onvoltage

Turn-off voltage

Hysteresis

IqVDR Quiescent Current Drivers

VFB > VREF

IqVcc Device Quiescent current

VFB > VREF

SHUTDOWN SECTION

SHDN Device On

Device Off

ISHVDR Drivers shutdown current

SHDN to GND

ISHVCC Devices shutdown current

SHDN to GND

SOFT START SECTION

ISS Soft Start current

VSS = 0.4V

Active Soft start and voltage

CURRENT LIMIT AND ZERO CURRENT COMPARATOR

ILIM input bias current

RILIM = 2KΩ to 200KΩ

Zero Crossing Comparator offset

Phase-gnd

DKILIM Current limit factor

Min.

1

3

2.86

2.75

1.2

4

300

4.6

-2

1.6

Typ. Max. Unit

28

V

5.5

V

2.97

V

2.9

V

90

mV

7

20

µA

400 600

µA

V

0.6

V

5

µA

1

15

µA

6

µA

400 500 mV

5

5.4

µA

2

mV

1.8

2

µA

3/23

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