150KHZ 500MA STEP DOWN VOLTAGE REGULATOR
FSP3127
FUNCTIONAL BLOCK DIAGRAM
FUNCTIONAL DESCROPTION
Pin Functions
V
IN
This is the positive input supply for the IC switching regulator. A suitable input bypass capacitor must be present at
this pin to minimize voltage transients and to supply the switching currents needed by the regulator.
Ground
Circuit ground.
Output
Internal switch. The voltage at this pin switches between (V
IN
- V
SAT
) and approximately +0.5V, with a duty cycle of
V
OUT
/V
IN
. To minimize coupling to sensitive circuitry, the PC board copper area connected to this pin should be kept to
a minimum.
Feedback
Senses the regulated output voltage to complete the feedback loop.
ON/OFF
Allows the switching regulator circuit to be shut down using logic level signals thus dropping the total input supply
current to approximately 80 mA. Pulling this pin below a threshold voltage of approximately 1.3V turns the regulator
on, and pulling this pin above 1.3V (up to a maximum of 25V) shuts the regulator down. If this shutdown feature is not
needed, the ON/OFF pin can be wired to the ground pin or it can be left open, in either case the regulator will be in the
ON condition.
TYPICAL APPLICATION CIRCUIT
3/8
2007-4-9
FOSLINK [ FOSLINK SEMICONDUCTOR CO.,LTD ]
