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Revision 1.02

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AS1326

Data Sheet - P i n o u t

4 Pinout

Pin Assignments

Figure 2. Pin Assignments (Top View)

Pin Descriptions

Table 2. Pin Descriptions

Pin Number

Pin Name

Description

1

ISET

N-Channel Current-Limit Control. For maximum current limit, connect to pin REF.

To reduce current, supply a voltage between pin REF and GND using a resistive

voltage-divider. If soft-start is desired, connect a capacitor from this pin to GND.

2REF

1.250V Internal Reference Bypass. Connect a 10nF ceramic bypass capacitor to

GND. Up to 50µA of external load current is allowed.

3GND

Ground. Connect this pin to PGND using a short trace. The exposed pad can be

used for this routing.

4FB

DC-DC Converter Feedback Input. To set fixed output voltage of +3.3V, connect

this pin to GND. For adjustable output of 2.5 to 5.0V, connect to a resistor-divider

network from pin OUT to GND. The set point for this pin is 1.24V.

5OUT

IC Power, Supplied from the Output. Bypass this pin to GND with a 330nF

ceramic capacitor, and connect to POUT with a 10

Ω series resistor (see Figure 19

on page 11).

6

CLK/SEL

Clock Input for the DC-DC Converter. This pin is also used to program the

operational mode as follows:

0 = Normal operation – the AS1326A operates at a fixed frequency, and switches

into automatic powersave operation if the load is minimized.

1 = Forced-PWM mode – the AS1326A operates in low-noise, constant-frequency

mode at all loads.

Clocked = Forced-PWM mode with the internal oscillator synchronized to this pin in

500 to 1200kHz range.

7PGND

N-Channel Power MOSFET Switch Source

8LX

Inductor Connection

9POUT

Power Output. P-channel synchronous rectifier source.

10

ONN

Enable Low (AS1326A only). Must be connected to GND for normal operation.

0 = The AS1326A is on.

1 = The AS1326A is off.

ON

Enable High (AS1326B only). Must be connected to OUT for normal operation.

0 = The AS1326B is off.

1 = The AS1326B is on.

11

NC

Exposed Pad. This pad is not connected internally. It can be used for ground

connection between GND and PGND.

AS1326A/

AS1326B

4

FB

3

GND

2

REF

1

ISET

6 CLK/SEL

7 PGND

9 POUT

10 ONN/ON

5

OUT

8 LX

11