ViewSonic VS11280 Service Manual page 20

DC-DC AP1117E33L(U701)
AP1117 is a low dropout positive adjustable or fixed-mode regulator with minimum of 1A output current capability.
The product is specifically designed to provide well-regulated supply for low voltage IC applications such as
high-speed bus termination and low current 3.3V logic supply.
AP1117 is also well suited for other applications such as VGA cards. AP1117 is guaranteed to have lower than 1.4V
dropout at full load current making it ideal to provide well-regulated outputs of 1.25 to 5.0 with 6.4V to 12V input
supply.
Block Diagrm
Pin Descriptions
Name I/O
Adj (GND) I
Vout O
Vin I
Pin #
A resistor divider from this pin to the Vout pin and ground sets the output voltage.
1
(Ground only for Fixed-Mode)
The output of the regulator. A minimum of 10uF capacitor (0.15Ω ≤ESR ≤20Ω)
2
must be connected from this pin to ground to insure stability.
The input pin of regulator. Typically a large storage capacitor (0.15Ω ≤ESR
≤20Ω) is connected from this pin to ground to insure that the input voltage does
3 not sag below the minimum dropout voltage during the load transient response.
This pin must always be 1.3V higher than Vout in order for the device to regulate
properly.
Function
20