LM2576T-15/NOPB National Semiconductor, LM2576T-15/NOPB Datasheet - Page 19
![IC REG SIMPLE SWITCHER TO-220-5](/photos/7/60/76069/pkg_t05a_drawing__14_sml.jpg)
LM2576T-15/NOPB
Manufacturer Part Number
LM2576T-15/NOPB
Description
IC REG SIMPLE SWITCHER TO-220-5
Manufacturer
National Semiconductor
Series
SIMPLE SWITCHER®r
Type
Step-Down (Buck)r
Datasheet
1.LM2576T-5.0NOPB.pdf
(24 pages)
Specifications of LM2576T-15/NOPB
Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
15V
Current - Output
3A
Frequency - Switching
52kHz
Voltage - Input
4 ~ 40 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Through Hole
Package / Case
TO-220-5 (Straight Leads)
Input Voltage
40V
Output Current
3A
Output Voltage
15V
No. Of Pins
5
Operating Temperature Range
-40°C To +125°C
Msl
MSL 1 - Unlimited
Switching Frequency Max
52kHz
Filter Terminals
Through Hole
Rohs Compliant
Yes
Input Voltage Primary Max
40V
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-
Other names
*LM2576T-15
*LM2576T-15/NOPB
LM2576T-15
*LM2576T-15/NOPB
LM2576T-15
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LM2576T-15/NOPB
Manufacturer:
TI/德州仪器
Quantity:
20 000
Additional Applications
Note: Complete circuit not shown (see Figure 10).
DELAYED STARTUP
The ON /OFF pin can be used to provide a delayed startup
feature as shown in Figure 14. With an input voltage of 20V
and for the part values shown, the circuit provides approxi-
mately 10 ms of delay time before the circuit begins switch-
Definition of Terms
BUCK REGULATOR
A switching regulator topology in which a higher voltage is
converted to a lower voltage. Also known as a step-down
switching regulator.
BUCK-BOOST REGULATOR
A switching regulator topology in which a positive voltage is
converted to a negative voltage without a transformer.
DUTY CYCLE (D)
Ratio of the output switch’s on-time to the oscillator period.
FIGURE 13. Undervoltage Lockout
for Buck-Boost Circuit
FIGURE 15. 1.2V to 55V Adjustable 3A Power Supply with Low Output Ripple
(Continued)
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19
ing. Increasing the RC time constant can provide longer
delay times. But excessively large RC time constants can
cause problems with input voltages that are high in 60 Hz or
120 Hz ripple, by coupling the ripple into the ON /OFF pin.
ADJUSTABLE OUTPUT, LOW-RIPPLE POWER SUPPLY
A 3A power supply that features an adjustable output voltage
is shown in Figure 15. An additional L-C filter that reduces
the output ripple by a factor of 10 or more is included in this
circuit.
Note: Complete circuit not shown.
CATCH DIODE OR CURRENT STEERING DIODE
The diode which provides a return path for the load current
when the LM2576 switch is OFF.
EFFICIENCY (η)
The proportion of input power actually delivered to the load.
FIGURE 14. Delayed Startup
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