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PDF LM2575 Data sheet ( Hoja de datos )
| Número de pieza | LM2575 | |
| Descripción | 52kHz Simple 1A Buck Regulator | |
| Fabricantes | Micrel Semiconductor | |
| Logotipo |  |
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 1. - 1A, Step-Down Switching Regulator  Hay una vista previa y un enlace de descarga de LM2575 (archivo pdf) en la parte inferior de esta página. Total 12 Páginas | ||
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LM2575
52kHz Simple 1A Buck Regulator
General Description
Features
The LM2575 series of monolithic integrated circuits
provide all the active functions for a step-down (buck)
switching regulator. Fixed versions are available with a
3.3V, 5V, 12V, fixed output. Adjustable versions have an
output voltage range from 1.23V to 37V. Both versions are
capable of driving a 1A load with excellent line and load
regulation.
These regulators are simple to use because they require a
minimum number of external components and include
internal frequency compensation and a fixed-frequency
oscillator.
The LM2575 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.
A standard series of inductors available from several
different manufacturers are ideal for use with the LM2575
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 output load conditions. The oscillator frequency is
guaranteed 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.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
• 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 1A output current
• Wide input voltage range
– 4V to 40V
• Wide output voltage range
– 1.23V to 37V
• Requires only 4 external components
• 52kHz fixed frequency internal oscillator
• Low power standby mode IQ typically <200µA
• 80% efficiency (adjustable version typically >80%)
• Uses readily available standard inductors
• Thermal shutdown and current limit protection
• 100% electrical thermal limit burn-in
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
7V–40V
Unregulated
DC Input 1
4
Feedback
+5V, 1A
Regulated
+VIN LM2575-5.0 Output L1
Output
+
CIN
100µF
35
Gnd On/Off
2
330µH
D1
1N5822
+
COUT
330µF
7V–40V
Unregulated
DC Input
1
+VIN
LM2575
+
CIN
100µF
35
Gnd On/Off
4 Feedback
Output L1
2 330µH
D1
1N5822
+
COUT
330µF
+5V, 1A
Regulated
Output
R2 3.09k
R1 1k
Note: Pin numbers are for TO-220 Package
Fixed Regulation in Typical Application
Note: Pin numbers are for TO-220 Package
( )VOUT = 1.23
1+
R2
R1
Adjustable Regulation 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
May 2009
1 M9999-051209-B
1 page  
Micrel, Inc.
LM2575
Symbol Parameter
Condition
DEVICE PARAMETERS, ADJUSTABLE REGULATOR
IB Feedback Bias Current
VOUT = 5V
DEVICE PARAMETERS, FIXED and ADJUSTABLE REGULATORS
fO Oscillator Frequency
Typ
50
52
VSAT
DC
ICL
Saturation Voltage
Max Duty Cycle (ON)
Current Limit
IOUT = 1A (Note 4)
(Note 5)
Peak Current, tON ≤ 3µs (Note 4)
0.9
98
2.2
IL Output Leakage Current VIN = 40V, (Note 6),
IQ Quiescent Current
(Note 6)
(Note 6)
Output = 0V
Output = –1V
Output = –1V
75
5
ISTBY
Standby Quiescent Current
ON/OFF Pin = 5V (OFF)
50
θJA Thermal Resistance
θJA
θJC
θJA
θJA
T Package, Junction to Ambient (Note 7)
T Package, Junction to Ambient (Note 8)
T Package, Junction to Case
N Package, Junction to Ambient (Note 9)
WM Package, Junction to Ambient (Note 9)
ON/OFF CONTROL, FIXED and ADJUSTABLE REGULATORS Test Circuit Figure 1
VIH ON/OFF Pin Logic
VIL Input Level
VOUT = 0V
VOUT = 5V
IIH ON/OFF Pin Logic
Current
ON /OFF Pin = 5V (OFF)
IIL ON /OFF Pin = 0V (ON)
65
45
2
85
100
1.4
1.2
4
0.01
LM2575
Limit
(Note 2)
100/500
47/42
58/63
1.2/1.4
93
1.7/1.3
3.0/3.2
2
30
10
200
Units
(Limits)
nA
kHz
kHz(min)
kHz(max)
V
V(max)
%
%(max)
A
A(min)
A(max)
mA(max)
mA
mA(max)
mA
mA(max)
µA
µA(max)
°C/W
2.2/2.4
1.0/0.8
30
10
V(min)
V(max)
µA
µA(max)
µA
µA(max)
Notes:
1. Absolute Maximum Rating indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device
is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical
Characteristics.
2. All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). All room temperature limits are100%
production tested. All limits at temperature extreme are guaranteed via testing.
3. External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the
LM2575/LM1575 is used as shown in Figure 1 test circuit, system performance will be shown in system parameters section of Electrical
Characteristics.
4. Output (pin 2) sourcing current. No diode, inductor or capacitor connected to output.
5. Feedback (pin 4) removed from output and connected to 0V.
6. Feedback (pin 4) removed from output and connected to 12V to force the output transistor OFF.
7. Junction to ambient thermal resistance (no external heat sink) for the 5-pin TO-220 package mounted vertically, with 1/2" leads in a socket, or on PC
board with minimum copper area.
8. Junction to ambient thermal resistance (no external heat sink) for the 5-pin TO-220 package mounted vertically, with 1/4" leads soldered to PC
board containing approximately 4 square inches of copper area surrounding the leads.
9. Junction to ambient thermal resistance with approximately 1 square inch of pc board copper surrounding the leads. Additional copper will lower
thermal resistance further.
May 2009
5 M9999-051209-B
5 Page 
Micrel, Inc.
LM2575
5-Pin TO-220 (T)
May 2009
5-Pin TO-263 (T)
11
M9999-051209-B
11 Page | ||
| Páginas | Total 12 Páginas | |
| PDF Descargar | [ Datasheet LM2575.PDF ] | |
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