L7985 datasheet(4/42 Pages) STMICROELECTRONICS

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Pin settings

L7985

4/42

DocID022446 Rev 7

Pin settings

1.1

Pin connection

Figure 2. Pin connection (top view)

1.2

Pin description

Table 1. Pin description

No.

(VFQFPN)

No.

(HSOP)

Type

Description

1 - 2

OUT

Regulator output

SYNCH

Master/slave synchronization. When it is left floating,

a signal with a phase shift of half a period, with respect to the

power turn-on, is present at the pin. When connected to an

external signal at a frequency higher than the internal one,

the device is synchronized by the external signal, with zero

phase shift.

Connecting together the SYNCH pin of two devices, the one

with a higher frequency works as master and the other one

as slave; so the two power turn-ons have a phase shift of

half a period.

A logical signal (active high) enables the device. With EN

higher than 1.2 V the device is ON and with EN lower than

0.3 V the device is OFF.

COMP

Error amplifier output to be used for loop frequency

compensation.

Feedback input. By connecting the output voltage directly to

this pin the output voltage is regulated at 0.6 V. To have

higher regulated voltages an external resistor divider is

required from VOUT to the FB pin.

FSW

The switching frequency can be increased connecting an

external resistor from the FSW pin and ground. If this pin is

left floating, the device works at its free-running frequency of

250 KHz.

GND

Ground

9 - 10

VCC

Unregulated DC input voltage.

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