AST1S31HF Datasheet, PDF (4/33 Pages) STMicroelectronics – Internal soft-start and enable

Pin settings
1
Pin settings
1.1
Pin connection
Figure 2. Pin connection (top view)
AST1S31HF
1.2
Pin description
Table 1. Pin description
No.
Type
Description
1
VINA
Unregulated DC input voltage
2
EN
Enable input. With EN higher than 1.5 V the device in ON and with EN
lower than 0.5 V the device is OFF.
Feedback input. Connecting the output voltage directly to this pin the
3
FB
output voltage is regulated at 0.8 V. To have higher regulated voltages an
external resistor divider is required from Vout to the FB pin.
4
AGND
Ground
Open drain Power Good (POR) pin. It is released (open drain) when the
output voltage is higher than 0.92 * V_OUT with a delay of 170 s. If the
5
PG
output voltage is below 0.92 * V_OUT, the POR pin goes to low impedance
immediately.
If not used, it can be left floating or to GND.
6
VINSW Power input voltage
7
SW
Regulator output switching pin
8
PGND
Power ground
9
ePAD
Exposed pad connected to ground
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DocID026968 Rev 2