ViewSonic VA2013wm-4, Service Manual

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DC to DC--- AP1117D33L (U701) and AP1117E18LA (U704)
AP1117 is a low dropout positive adjustable or fixed-mode regulator with 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 18V input supply.
Pin Descriptions
Name I/O Pin # Function
Adj (GND) I 1
A resistor divider from this pin to the Vout pin and ground sets the output voltage.
(Ground only for Fixed-Mode)
Vout O 2
The output of the regulator. A minimum of 10uF capacitor (0.15 Ω ≤ ESR ≤ 20 Ω )
must be connected from this pin to ground to insure stability.
Vin I 3
The input pin of regulator. Typically a large storage capacitor (0.15 Ω ≤ ESR
≤ 20 Ω ) is connected from this pin to ground to insure that the input voltage does
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.