Pin Description

Pin Number (*)

Pin Name

Function

A1

FB

Feedback Analog Input. Connect to the output at the output filter capacitor (Figure 1)

B1

VSEL

Output Voltage Selection Input. Set this digital input to:

VDD for 1.8V output voltage (1.5V for LM2608ATL-1.3)

SGND for 1.5V output voltage (1.3V for LM2608ATL-1.3)

C1

VREF

External Reference Input. Drive this analog input with a 1.35V reference to set the output

voltage. The LM2608 uses an internal reference while in LDO mode. (see Note 5 in the

Electrical Characteristics table for further information.)

D1

SYNC/MODE

Synchronization Input. Use this digital input for frequency synchronization or mode control.

Set:

SYNC/MODE = high for low-noise 600kHz PWM mode

SYNC/MODE = low for low-current LDO mode

SYNC/MODE = 500kHz - 1MHz external clock for synchronization to an external clock in

PWM mode. See Synchronization and Operating Modes in the Device Information section.

D2

EN

Enable Input. Set this Schmitt trigger digital input high for normal operation.

D3

PGND

Power Ground

C3

SW

Switching Node connection to the internal PFET switch and NFET synchronous rectifier.

Connect to an inductor with a saturation current rating that exceeds the max. Switch Peak

Current Limit specification of the LM2608 (Figure 1)

B3

PVIN

Power Supply Input to the internal PFET switch. Connect to the input filter capacitor

(Figure 1).

A3

VDD

Analog Supply Input. If board layout is not optimum, an optional 0.1µF ceramic capacitor

is suggested (Figure 1)

A2

SGND

Analog and Control Ground

(*) Note that the pin numbering scheme for the Micro SMD package was revised in April,2002 to conform to JEDEC standard. Only the pin numbers were revised.

No changes to the physical location of the inputs/outputs were made. For reference purpose, the obsolete numbering had FB as pin 1, VSEL as pin 2, VREF as pin

3, SYNC as pin 4, EN as pin 5, PGND as pin 6, SW as pin 7, PVIN as pin 8, VDD as pin 9 and SGND as pin 10.

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