AN1882

Pins function

Doc ID 10209 Rev 4

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1

Pins function

Figure 2.

Pins connection

Figure 3.

MSOP8 package

Table 1.

Pin description

N.

Name

Description

1

RUN

Shutdown input. When connected to a lower voltage than 0.5 V (down to GND) the device stops

working. When connected to a higher voltage than 1.3 V (up to VCC) the device is enabled. The pin

must not be left floating

2

COMP

Error amplifier output. A compensation network has to be connected from this pin to GND. Usually a

220 pF capacitor is enough to guarantee the loop stability (see related section)

3

VFB

Error amplifier inverting input, used to adjust the output voltage (from 0.6 V to VIN) by an external

divider.

4

GND

Ground

5

LX

Switch output node. Common point between high side and low side MOSFETs

6

Input voltage. The operating input voltage range is from 2 V to 5.5 V. An internal UVLO circuit

realizes a 200 mV (typ) hysteresis

7

SYNC

Operating mode selector input. Low consumption mode, when connected to a higher voltage than

1.3 V (up to VCC). Low noise mode when connected to a lower than 0.5 V (down to GND).

Synchronization mode when connected to an external appropriate clock generator. This pin must

not be left floating

8

PGOOD

Power Good comparator output. It is an open drain output. A pull-up resistor should be connected

the regulated output voltage and goes high when the output voltage is greater than 90% of the

regulated output voltage. If not used, the pin can be left floating.