YB1696
150KHz, 3A PWM Buck Switching Regulator
Function Description
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
approximately V
OUT
/ V
IN
. To minimize
coupling to sensitive circuitry, the PC board
copper area connected to this pin should
be kept a minimum.
Feedback
Senses the regulated output voltage to
complete the feedback loop.
ON
/OFF
open, in either case the regulator will be in
the ON condition.
Thermal Considerations
The YB1696 is available in a 5-pin surface
mount TO-263.
The TO-263 surface mount package tab is
designed to be soldered to the copper on a
printed circuit board. The copper and the
board are the heat sink for this package
and the other heat producing components,
such as the catch diode and inductor. The
PC board copper area that the package is
soldered to should be at least 0.8 in
2
, and
ideally should have 2 or more square
inches of 2 oz. Additional copper area
improves the thermal characteristics, but
with
copper
areas
greater
than
approximately
6
in
2
,
only
small
improvements in heat dissipation are
realized. If further thermal improvements
are needed, double sided, multilayer PC
board with large copper areas and/or
airflow are recommended.
The YB1696 (TO-263 package) junction
temperature
rise
above
ambient
temperature with a 2A load for various input
and output voltages. This data was taken
with the circuit operating as a buck
switching regulator with all components
mounted on a PC board to simulate the
junction
temperature
under
actual
operating conditions. This curve can be
Allows the switching regulator circuit to be
shutdown using logic level signals thus
dropping the total input supply current to
approximately 150uA. 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
YB1696 MRev.1.1
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YOBON [ YOBON TECHNOLOGIES,INC. ]
