L6730 datasheet(9/52 Pages) STMICROELECTRONICS

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L6730 - L6730B

Pin connections and functions

Doc ID 11938 Rev 3

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TMASK

The user can select two different values for the leading edge blanking

time on the peak overcurrent protection by connecting this pin to VCCDR or

GND. The device captures the analog value present at this pin at the

start-up when VCC meets the UVLO threshold.

5GND

All the internal references are referenced to this pin. Connect to the PCB

signal ground.

6FB

This pin is connected to the error amplifier inverting input. Connect it to

Vout through the compensation network. This pin is also used to sense

the output voltage in order to manage the over voltage conditions and the

PGood signal.

7COMP

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

compensate the voltage control loop.

SS/INH

The soft-start time is programmed connecting an external capacitor from

this pin and GND. The internal current generator forces a current of 10mA

through the capacitor. This pin is also used to inhibit the device: when the

voltage at this pin is lower than 0.5V the device is disabled.

EAREF

It is possible to set two internal references 0.6V / 1.2V or provide an

external reference from 0V to 2.5V:

VEAREF from 0% to 80% of VCCDR -> external reference

VEAREF from 80% to 95% of VCCDR -> VREF=1.2V

VEAREF from 95% to 100% of VCCDR -> VREF=0.6V

An internal clamp limits the maximum VEAREF at 2.5V (typ.). The device

captures the analog value present at this pin at the start-up when VCC

meets the UVLO threshold.

OSC

Connecting an external resistor from this pin to GND, the external

frequency can be increased according with the following equation:

Connecting a resistor from this pin to VCCDR (5V), the switching frequency

can be lowered according with the following equation:

If the pin is left open, the switching frequency is 400 KHz. Normally this

pin is at a voltage of 1.2V. In OVP the pin is pulled up to 4.5V (only in

latched mode). Don’t connect a capacitor from this pin to GND.

Table 4.

Pin connection (continued)

Pin n.

Name

Description

)

(

400

⋅

KHz

Fsw

OSC

)

(

400

⋅

−

KHz

Fsw

OSC

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