LM2575HVT-12 National Semiconductor, LM2575HVT-12 Datasheet - Page 21
![IC, SWITCHING REG 1A 12V, SMD, 2575](/photos/19/7/190790/42334036_sml.jpg)
LM2575HVT-12
Manufacturer Part Number
LM2575HVT-12
Description
IC, SWITCHING REG 1A 12V, SMD, 2575
Manufacturer
National Semiconductor
Datasheet
1.LM2575HVT-12.pdf
(27 pages)
Specifications of LM2575HVT-12
Primary Input Voltage
25V
No. Of Outputs
1
Output Voltage
12V
Output Current
1A
Voltage Regulator Case Style
TO-220
No. Of Pins
5
Operating Temperature Range
-40°C To +125°C
Svhc
No SVHC
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LM2575HVT-12/NOPB
Manufacturer:
IXYS
Quantity:
8 700
Additional Applications
Typical Load Current
200 mA for V
500 mA for V
Note: Pin numbers are for TO-220 package.
UNDERVOLTAGE LOCKOUT
In some applications it is desirable to keep the regulator off
until the input voltage reaches a certain threshold. An und-
ervoltage lockout circuit which accomplishes this task is
shown in Figure 12, while Figure 13 shows the same circuit
applied to a buck-boost configuration. These circuits keep
the regulator off until the input voltage reaches a predeter-
mined level.
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-
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 1A 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.
IN
IN
= −5.2V
= −7V
FIGURE 11. Negative Boost
V
TH
≈ V
Z1
+ 2V
BE
(Q1)
(Continued)
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Note: Complete circuit not shown.
Note: Pin numbers are for the TO-220 package.
Note: Complete circuit not shown (see Figure 10).
Note: Pin numbers are for the TO-220 package.
Note: Complete circuit not shown.
Note: Pin numbers are for the TO-220 package.
FIGURE 12. Undervoltage Lockout for Buck Circuit
FIGURE 13. Undervoltage Lockout
FIGURE 14. Delayed Startup
for Buck-Boost Circuit
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