TD1501 Techcode, TD1501 Datasheet - Page 11

• Manufacturer Part Number: TD1501
• Description: PWM Buck DC/DC Converter
• Manufacturer: Techcode

www.DataSheet.co.kr
Function Description
December, 20, 2005. Techcode Semiconductor Limited www.techcodesemi.com
Pin Functions
+V
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
duty cycle of approximately V
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
Allows the switching regulator circuit to be shutdown
using logic level signals thus dropping the total input
supply current to approximately 80uA. 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.
Thermal Considerations
The TD1501 is available in two packages, a 5-pin
TO-220B/TO-220 and a 5-pin surface mount TO-263.
The TO-220B/TO-220 package needs a heat sink under
most conditions. The size of the heatsink depends on
the input voltage, the output voltage, the load current
and the ambient temperature. The TD1501 junction
IN
T
3A 150KHz PWM Buck DC/DC Converter
echcode
IN
– V
SAT
) and approximately – 0.5V, with a
OUT
/ V
®
IN
. To minimize
11
temperature rises above ambient temperature for a 3A
load and different input and output voltages. The data
for
(TO-220B/TO-220 package) operating as a buck
switching regulator in an ambient temperature of 25
(still air). These temperature rise numbers are all
approximate and there are many factors that can affect
these temperatures. Higher ambient temperatures
require more heat sinking.
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 0.4 in
ideally should have 2 or more square inches of 2 oz.
Additional
characteristics, but with copper areas greater than
approximately 6 in
dissipation are realized. If further thermal improvements
are needed, double sided, multilayer PC board with large
copper areas and/or airflow are recommended.
The TD1501 (TO-263 package) junction temperature rise
above ambient temperature with a 3A 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 used for a quick check for the
approximate junction temperature for various conditions,
but be aware that there are many factors that can affect
the junction temperature.
than 3A are used, double sided or multilayer PC boards
with large copper areas and/or airflow might be needed,
especially for high ambient temperatures and high output
voltages.
For the best thermal performance, wide copper traces
and generous amounts of printed circuit board copper
should be used in the board layout. (Once exception to
these
curves
copper
2
, only small improvements in heat
was
area
When load currents higher
taken
improves
DATASHEET
TD1501
with
the
the
TD1501
thermal
2
, and
o
C
Datasheet pdf - http://www.DataSheet4U.net/