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AS1344

Datasheet - A p p l i c a t i o n I n f o r m a t i o n

9 Application Information

Shutdown and Output Discharge

A logic low on the EN pin shuts down the AS1344 and a logic high on the EN pin powers on the device. In shutdown

mode the supply current drops to below 3µA and the POK pin is set to high impedance to maximize battery life.

When the battery disconnect switch is used, the battery is disconnected from the output and the output is discharged

Note:

discharged during shutdown but the output also must be fully discharged before the device is enabled again.

Battery Disconnect

The AS1344 has an integrated PMOS switch that can be used to disconnect the battery during shutdown. The opera-

tion voltage of this switch is limited to 3.6V. When EN is high, the switch is closed and supplies the inductor. Due to the

(EQ 1)

Softstart Function

lation between the resistor value, the supply voltage and the startup time see Figure 33. For the correlation between

resistor value, the supply voltage and the peak current see Figure 34. Connect VIN directly to VCC (no resistor) to dis-

able the softstart Function.

As an example some peak current and time values are listed at a given Rv in Table 4.

Ω]0

1.0

1.5

2.0

2.4

3.0

1.76

0.81

0.66

0.56

0.50

0.42

t [ms]

25

76

100

130

156

204

0

100

200

300

400

500

600

700

800

1

1.4

1.8

2.2

2.6

3

3.4

Input Voltage (V)

0 Ohm

1.0 Ohm

1.5 Ohm

2.0 Ohm

2.4 Ohm

3.0 Ohm

0

0.5

1

1.5

2

2.5

3

3.5

1

1.4

1.8

2.2

2.6

3

3.4

Input Voltage (V)

0 Ohm

1.0 Ohm

1.5 Ohm

2.0 Ohm

2.4 Ohm

3.0 Ohm

5.1 Ohm