LM2640

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SNVS019B – DECEMBER 1998 – REVISED APRIL 2013

Pin Description(1) (continued)

Pin #

Name

Function

21

CSL1

The sense point for the negative side of the voltage across the current sense resistor (R4) placed in

series with output #1.

22

LIN

This pin provides a low-current (50 mA max) 5V output. This output is always on, and can not be turned

off by either the SD or ON/OFF pins.

23

IN

This is the connection for the main input power.

24

LDRV2

The drive for the gate of the low-side switching FET (synchronous rectifier) used for output #2.

25

CBOOT2

The bootstrap capacitor (C9) for output #2 is returned to this point.

26

SW2

This is the switching output drive point of the two power FETs which produce output #2.

27

HDRV2

The drive for the gate of the high-side switching FET used for output #2.

28

CSL2

The sense point for the negative side of the voltage across the current sense resistor (R13) placed in

series with output #2.

Typical Application Circuits

Note: Alternate recommended inductor is Sumida CDRH-125-100MC. If this inductor is used, R6 should be changed

to 3.3k and R11 should be 5.1k.

Figure 2. Application With 5V/3A and 3.3V/4A Outputs

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