Image LM2576-5.0WU
型号: LM2576-5.0WU
厂商: Micrel Inc Micrel Inc
标准:
分类: 半导体集成电路 - IC
描述: voltage regulators - switching regulators 3A step-down smps regulator (rohs compliant)
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LM2576-5.0WU的详细信息

Manufacturer: Micrel
Product Category: Voltage Regulators - Switching Regulators
RoHS: Yes
Input Voltage MAX: 40 V
Switching Frequency: 52 kHz
Output Voltage: 5 V
Output Current: 3 A
Number of Outputs: 1 Output
Maximum Operating Temperature: + 85 C
Mounting Style: SMD/SMT
Package / Case: TO-263-5
Brand: Micrel
Input Voltage MIN: 4 V
Minimum Operating Temperature: - 40 C
Packaging: Tube
Series: LM2576
Factory Pack Quantity: 50
Topology: Buck
Type: Buck Regulators
LM2576  
52kHz Simple 3A Buck Regulator  
General Description  
Features  
The LM2576 series of monolithic integrated circuits provide  
all the active functions for a step-down (buck) switching  
regulator.Fixedversionsareavailablewitha3.3V,5V,or12V  
fixed output. Adjustable versions have an output voltage  
rangefrom1.23Vto37V. Bothversionsarecapableofdriving  
a 3A load with excellent line and load regulation.  
• 3.3V, 5V, 12V, and adjustable output versions  
• Voltage over specified line and load conditions:  
Fixed version: ±3% max. output voltage  
Adjustable version: ±2% max. feedback voltage  
• Guaranteed 3A output current  
• Wide input voltage range:  
4V to 40V  
• Wide output voltage range  
1.23V to 37V  
These regulators are simple to use because they require a  
minimumnumberofexternalcomponentsandincludeinternal  
frequency compensation and a fixed-frequency oscillator.  
The LM2576 series offers a high efficiency replacement for  
popular three-terminal adjustable linear regulators. It  
substantially reduces the size of the heat sink, and in many  
cases no heat sink is required.  
• Requires only 4 external components  
• 52kHz fixed frequency internal oscillator  
• Low power standby mode I typically < 200µA  
Q
• 80% efficiency (adjustable version typically > 80%)  
• Uses readily available standard inductors  
• Thermal shutdown and current limit protection  
• 100% electrical thermal limit burn-in  
Astandardseriesofinductorsavailablefromseveraldifferent  
manufacturers are ideal for use with the LM2576 series. This  
feature greatly simplifies the design of switch-mode power  
supplies.  
The feedback voltage is guaranteed to ±2% tolerance for  
adjustable versions, and the output voltage is guaranteed to  
±3% for fixed versions, within specified input voltages and  
outputloadconditions.Theoscillatorfrequencyisguaranteed  
to ±10%. External shutdown is included, featuring less than  
200µA standby current. The output switch includes cycle-by-  
cycle current limiting and thermal shutdown for full protection  
under fault conditions.  
Applications  
• Simple high-efficiency step-down (buck) regulator  
• Efficient pre-regulator for linear regulators  
• On-card switching regulators  
• Positive to negative converter (inverting Buck-Boost)  
• Isolated Flyback Converter using minimum number of  
external components  
• Negative Boost Converter  
Typical Applications  
7V40V  
7V40V  
Unregulated  
DC Input  
Unregulated  
DC Input  
+5V, 1A  
Regulated  
Output  
+5V, 1A  
Regulated  
Output  
4
4
Feedback  
Feedback  
1
1
LM2575-5.0  
LM2575  
5
L1  
330µH  
D1  
L1  
330µH  
D1  
Output  
2
Output  
2
+VIN  
+VIN  
+
+
+
+
R2 3.09k  
R1 1k  
3
5
3
C
C
IN  
IN  
Gnd On/Off  
Gnd On/Off  
COUT  
330µF  
COUT  
330µF  
100µF  
100µF  
1N5822  
1N5822  
Note: Pin numbers are for TO-220 Package  
Note: Pin numbers are for TO-220 Package  
R2  
VOUT = 1.23 1 +  
( )  
R1  
Fixed Regulator in Typical Application  
Adjustable Regulator in Fixed Output Application  
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com  
August 2005  
1
M9999-082605-B  

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