LM2576S-3.3 National Semiconductor, LM2576S-3.3 Datasheet - Page 10

• Manufacturer Part Number: LM2576S-3.3
• Description: IC, STEP-DOWN VOLTAGE REGULATOR, TO-263
• Manufacturer: National Semiconductor

Specifications of LM2576S-3.3

• Primary Input Voltage: 12V
• No. Of Outputs: 1
• Output Voltage: 3.3V
• Output Current: 3A
• No. Of Pins: 5
• Operating Temperature Range: -40°C To +125°C
• Supply Voltage Range: 4V To 40V
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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Test Circuit and Layout Guidelines
As in any switching regulator, layout is very important. Rap-
idly switching currents associated with wiring inductance
generate voltage transients which can cause problems. For
minimal inductance and ground loops, the length of the leads
indicated by heavy lines should be kept as short as possible.
C
C
D
L
R
R
where V
1
IN
OUT
1
1
2
— 100 µH, Pulse Eng. PE-92108
— Schottky, MBR360
— 2k, 0.1%
— 6.12k, 0.1%
— 100 µF, 75V, Aluminum Electrolytic
— 1000 µF, 25V, Aluminum Electrolytic
REF
= 1.23V, R1 between 1k and 5k.
Adjustable Output Voltage Version
Fixed Output Voltage Versions
FIGURE 2.
10
Single-point grounding (as indicated) or ground plane con-
struction should be used for best results. When using the
Adjustable version, physically locate the programming resis-
tors near the regulator, to keep the sensitive feedback wiring
short.
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