LM2575-3.3BN [MICREL]

52kHz Simple 1A Buck Regulator; 52kHz简单1A降压稳压器
LM2575-3.3BN
型号: LM2575-3.3BN
厂家: MICREL SEMICONDUCTOR    MICREL SEMICONDUCTOR
描述:

52kHz Simple 1A Buck Regulator
52kHz简单1A降压稳压器

稳压器 开关式稳压器或控制器 电源电路 开关式控制器 光电二极管
文件: 总7页 (文件大小:93K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
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  
rangefrom1.23Vto37V. Bothversionsarecapableofdriving  
a 1A 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 1A 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 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.  
• 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 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  
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  
7V–40V  
Unregulated  
DC Input  
7V–40V  
Unregulated  
DC Input  
+5V, 1A  
Regulated  
Output  
+5V, 1A  
Regulated  
Output  
4
4
Feedback  
L1  
Feedback  
L1  
1
1
LM2575-5.0  
LM2575  
3 5  
Output  
2
Output  
2
+VIN  
+VIN  
330µH  
330µH  
+
+
+
+
R2 3.09k  
R1 1k  
3
5
C
C
IN  
IN  
Gnd On/Off  
Gnd On/Off  
D1  
1N5822  
D1  
1N5822  
COUT  
330µF  
COUT  
330µF  
100µF  
100µF  
Note: Pin numbers are for TO-220 Package  
Note: Pin numbers are for TO-220 Package  
R2  
V
OUT = 1.23 1 +  
( )  
R1  
Fixed Regulator in Typical Application  
Adjustable Regulator in Fixed Output Application  
August 1999  
1
M2575  
LM2575  
Micrel  
Ordering Information  
Part Number‡  
LM2575BN*  
Temperature Range  
–40°C to +85 °C  
–40°C to +85 °C  
–40°C to +85 °C  
–40°C to +85 °C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
Package  
16-pin Plastic DIP  
16-pin Plastic DIP  
16-pin Plastic DIP  
16-pin Plastic DIP  
24-pin Wide SOIC  
24-pin Wide SOIC  
24-pin Wide SOIC  
24-pin Wide SOIC  
5-lead TO-220  
LM2575-3.3BN  
LM2575-5.0BN  
LM2575-12BN  
LM2575BWM*  
LM2575-3.3BWM  
LM2575-5.0BWM  
LM2575-12BWM  
LM2575BT*†  
LM2575-3.3BT†  
LM2575-5.0BT†  
LM2575-12BT†  
LM2575BU*  
5-lead TO-220  
5-lead TO-220  
5-lead TO-220  
5-lead TO-263  
LM2575-3.3BU  
LM2575-5.0BU  
LM2575-12BU  
5-lead TO-263  
5-lead TO-263  
5-lead TO-263  
* Adjustable output regulators.  
Contact factory for bent or staggered leads option.  
Pin Configurations  
5-LEAD TO-220 (T)  
5-LEAD TO-263 (U)  
GND  
GND  
5- ON/OFF  
5- ON/OFF  
4- FEEDBACK  
3- GROUND  
2- OUTPUT  
4- FEEDBACK  
3- GROUND  
2- OUTPUT  
1- V  
1- V  
IN  
IN  
24-LEAD SOIC (WM)  
1
2
24  
23  
22  
21  
20  
19  
18  
17  
16  
15  
14  
13  
PWR GND  
NC  
NC  
NC  
16-LEAD DIP (N)  
3
4
NC  
NC  
NC  
NC  
1
2
3
4
5
6
7
8
16  
15  
14  
13  
12  
11  
10  
9
NC  
NC  
V
IN  
5
6
NC  
NC  
NC  
NC  
NC  
OUTPUT  
NC  
GND  
GND  
GND  
GND  
NC  
7
FB  
OUTPUT  
OUTPUT  
NC  
8
9
GND  
NC  
FB  
SIG GND  
NC  
10  
11  
12  
ON/OFF  
NC  
PWR GND  
V
IN  
NC  
ON/OFF  
V
IN  
NC  
LM2575  
2
August 1999  
LM2575  
Micrel  
Absolute Maximum Ratings (Note 1)  
Operating Ratings  
Maximum Supply Voltage  
45V  
Temperature Range  
Supply Voltage  
–40°C TJ +125°C  
ON/OFF Pin Input Voltage  
Output Voltage to Ground (Steady State)  
Power Dissipation  
Storage Temperature Range  
Minimum ESD Rating  
–0.3V V +40V  
–1V  
Internally Limited  
–65°C to +150°C  
40V  
C = 100pF, R = 1.5kΩ  
FB Pin  
2 kV  
1 kV  
Lead Temperature (soldering, 10 sec.)  
Maximum Junction Temperature  
260°C  
150°C  
Electrical Characteristics Specifications with standard typeface are for TJ = 25°C, and those with boldface type apply  
over full Operating Temperature Range. Unless otherwise specified, VIN = 12V, and ILOAD = 200mA.  
LM2575  
Symbol  
Parameter  
Conditions  
Typ  
Limit  
Units  
(Note 2)  
(Limits)  
SYSTEM PARAMETERS, ADJUSTABLE REGULATORS (Note 3) Test Circuit Figure 1  
VOUT  
VOUT  
η
Feedback Voltage  
VIN = 12V , ILOAD = 0.2A  
OUT = 5V  
1.230  
1.230  
V
V
1.217  
1.243  
V(min)  
V(max)  
Feedback Voltage  
LM2575  
0.2A ILOAD 1A, 8V VIN 40V  
VOUT = 5V  
V
1.193/1.180  
1.267/1.280  
V(min)  
V(max)  
Efficiency  
VIN = 12V, ILOAD = 1A, VOUT = 5V  
82  
%
SYSTEM PARAMETERS, 3.3V REGULATORS (Note 3) Test Circuit Figure 1  
VOUT  
VOUT  
η
Output Voltage  
VIN = 12V , ILOAD = 0.2A  
OUT = 3.3V  
3.3  
V
V
3.234  
3.366  
V(min)  
V(max)  
Output Voltage  
LM2575-3.3  
0.2A ILOAD 1A, 8V VIN 40V  
VOUT = 3.3V  
3.3  
V
3.168/3.135  
3.432/3.465  
V(min)  
V(max)  
Efficiency  
VIN = 12V, ILOAD = 1A  
75  
%
SYSTEM PARAMETERS, 5V REGULATORS (Note 3) Test Circuit Figure 1  
VOUT  
VOUT  
η
Output Voltage  
VIN = 12V , ILOAD = 0.2A  
VOUT = 5V  
5.0  
V
4.900  
5.100  
V(min)  
V(max)  
Output Voltage  
LM2575-5.0  
0.2A ILOAD 1A, 8V VIN 40V  
VOUT = 5V  
5.0  
V
4.800/4.750  
5.200/5.250  
V(min)  
V(max)  
Efficiency  
VIN = 12V, ILOAD = 1A  
82  
12  
%
SYSTEM PARAMETERS, 12V REGULATORS (Note 3) Test Circuit Figure 1  
VOUT  
VOUT  
η
Output Voltage  
VIN = 25V , ILOAD = 0.2A  
VOUT = 12V  
V
11.760  
12.240  
V(min)  
V(max)  
Output Voltage  
LM2575-12  
0.2A ILOAD 1A, 15V VIN 40V  
VOUT = 12V  
12  
88  
V
11.520/11.400  
12.480/12.600  
V(min)  
V(max)  
Efficiency  
VIN = 25V, ILOAD = 1A  
%
August 1999  
3
M2575  
LM2575  
Micrel  
Electrical Characteristics (continued)  
LM2575  
Units  
Symbol  
Parameter  
Conditions  
Typ  
Limit  
(Limits)  
(Note 2)  
DEVICE PARAMETERS, ADJUSTABLE REGULATOR  
IB Feedback Bias Current VOUT = 5V  
DEVICE PARAMETERS, FIXED and ADJUSTABLE REGULATORS  
50  
52  
100/500  
nA  
fO  
Oscillator Frequency  
kHz  
47/42  
58/63  
kHz (min)  
kHz (max)  
VSAT  
DC  
Saturation Voltage  
Max Duty Cycle (ON)  
Current Limit  
IOUT = 1A (Note 4)  
(Note 5)  
0.9  
98  
V
1.2/1.4  
V(max)  
%
%(min)  
93  
ICL  
Peak Current, tON 3µs (Note 4)  
2.2  
A
1.7/1.3  
3.0/3.2  
A(min)  
A(max)  
IL  
Output Leakage Current VIN = 40V, (Note 6),  
(Note 6)  
Output = 0V  
Output = –1V  
Output = –1V  
2
mA(max)  
mA  
mA(max)  
7.5  
5
30  
IQ  
Quiescent Current  
(Note 6)  
mA  
10  
mA(max)  
ISTBY  
Standby Quiescent  
Current  
ON/OFF Pin = 5V (OFF)  
50  
µA  
µA(max)  
200  
θJA  
θJA  
θJC  
θJA  
θJA  
Thermal Resistance  
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 Amb. (Note 9)  
65  
45  
2
85  
100  
°C/W  
LM2575  
4
August 1999  
LM2575  
Micrel  
LM2575  
Units  
Symbol  
Parameter  
Conditions  
Typ  
Limit  
(Limits)  
(Note 2)  
ON/OFF CONTROL, FIXED and ADJUSTABLE REGULATORS Test Circuit Figure 1  
VIH  
VIL  
ON/OFF Pin Logic  
Input Level  
VOUT = 0V  
VOUT = 5V  
1.4  
1.2  
2.2/2.4  
1.0/0.8  
V(min)  
V(max)  
IIH  
ON /OFF Pin Logic  
Current  
ON /OFF Pin = 5V (OFF)  
4
µA  
µA(max)  
30  
10  
IIL  
ON/OFF Pin = 0V (ON)  
0.01  
µA  
µA(max)  
Note 1: AbsoluteMaximumRatingindicatelimitsbeyondwhichdamagetothedevicemayoccur. OperatingRatingsindicateconditionsforwhichthedevice  
is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical  
Characteristics.  
Note 2: All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face) . All room temperature limits are  
100% production tested. All limits at temperature extreme are guaranteed via testing.  
Note 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.  
Note 4: Output (pin 2) sourcing current. No diode, inductor or capacitor connected to output.  
Note 5: Feedback (pin 4) removed from output and connected to 0V.  
Note 6: Feedback (pin 4) removed from output and connected to 12V to force the output transistor OFF.  
Note 7: Junction to ambient thermal resistance (no external heat sink) for the 5-lead TO-220 package mounted vertically, with 1/2" leads in a socket, or  
on PC board with minimum copper area.  
Note 8: Junction to ambient thermal resistance (no external heat sink) for the 5-lead TO-220 package mounted vertically, with 1/4" leads soldered to PC  
board containing approximately 4 square inches of copper area surrounding the leads.  
Note 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.  
Typical Performance Characteristics  
Normalized  
Feedback Voltage  
vs Duty Cycle*  
Feedback Voltage*  
20  
15  
10  
5
25  
20  
15  
I
= 200 mA  
V
= 12V  
LOAD  
IN  
I
= 200mA  
LOAD  
Normalized to T = 25˚C  
J
10  
5
V
= 40V  
IN  
0
0
-5  
-5  
V
= 7V  
-10  
IN  
-10  
-15  
-15  
-20  
-20  
-25  
-75 -50 -25  
0
25 50 75 100125150  
0
20  
40  
60  
80  
100  
JUNCTION TEMPERATURE (˚C)  
DUTY CYCLE (%)  
* Adjustable version only  
August 1999  
5
M2575  
LM2575  
Micrel  
Typical Performance Characteristics (continued) (Circuit of Figure 1)  
Supply Current  
vs. Duty Cycle  
Standby  
Quiescent Current  
Supply Current  
20  
18  
20.0  
17.5  
200  
150  
Measured at  
Ground Pin  
V
= 40V  
IN  
T
= 25˚C  
J
16  
14  
12  
10  
8
15.0  
12.5  
10.0  
7.5  
5.0  
2.5  
0
V
= 5V  
OUT  
V
= 5V  
ON/OFF  
100  
50  
0
I
= 200 mA  
LOAD  
V
= 12V  
IN  
I
to 1A  
LOAD  
V
from 7V to 40V  
6
IN  
4
0
10 20  
30  
40 50  
60  
0
20  
40  
60  
80  
100  
-75 -50 -25 0 25 50 75 100 125150  
INPUT VOLTAGE (V)  
DUTY CYCLE (%)  
JUNCTION TEMPERATURE (˚C)  
Switch  
Saturation Voltage  
Current Limit  
Efficiency  
3
1.2  
1.0  
0.8  
100  
95  
VI = 25V  
N
V
= 12V  
OUT  
1A  
90  
2
1
0
-55˚C  
-40˚C  
85  
80  
200 mA  
200 mA  
1A  
25˚C  
75  
70  
65  
60  
V
= 3V  
0.6 125˚C  
150˚C  
OUT  
0.4  
-75 -50 -25  
0
25 50 75 100125 150  
0
0.2  
0.4  
0.6  
0.8  
1.0  
0
5
10 15 20 25 30 35 40  
INPUT VOLTAGE (V)  
JUNCTION TEMPERATURE (˚C)  
SWITCH CURRENT (A)  
Minimum Operating  
Voltage  
Line Regulation  
Feedback Pin Current  
5.0  
4.5  
14  
12  
100  
75  
Normalized to V = 10V  
IN  
V
= 5V  
OUT  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
10  
8
I
= 500mA  
50  
25  
LOAD  
= 25  
T
J
6
4
0
2
-25  
-50  
-75  
-100  
0
V
= 1.23V  
OUT  
= 200 mA  
-2  
-4  
I
LOAD  
0.5  
0
-6  
-75 -50 -25  
0
25 50 75 100125150  
0
5
10 15  
20  
25  
30  
-75 -50 -25  
0
25 50 75 100 125150  
JUNCTION TEMPERATURE (˚C)  
INPUT VOLTAGE (V)  
JUNCTION TEMPERATURE (˚C)  
Normalized  
Oscillator Frequency  
Dropout Voltage  
Output Voltage  
2.0  
1.5  
1.0  
100  
75  
+8  
+6  
V
IN  
= 12V  
Normalized at 25˚C  
V  
OUT  
= 5%  
I
= 200mA  
R
= 0.2Ω  
LOAD  
IND  
I
= 1A  
LOAD  
Normalized to T = 25˚C  
J
+4  
+2  
0
50  
25  
0
-25  
-50  
-2  
V
= 40V  
I
= 200 mA  
IN  
LOAD  
-4  
0.5  
0
-75  
--6  
-8  
V
= 12V  
IN  
0 25 50 75 100125150  
-100  
-75 -50 -25  
0
25 50 75 100125150  
-75 -50 -25 0 25 50 75 100125150  
-75 -50 -25  
JUNCTION TEMPERATURE (˚C)  
JUNCTION TEMPERATURE (˚C)  
JUNCTION TEMPERATURE (˚C)  
LM2575  
6
August 1999  
LM2575  
Micrel  
Typical Performance Characteristics (Circuit of Figure 1)  
Load Transient Response  
Switching Waveforms  
+100mV  
0
A
10V  
0
Output  
Voltage  
Change  
–100mV  
B
1A  
0
1A  
.5A  
0
C
D
1.0A  
0.5A  
0
Output  
Current  
100µS/div.  
V
= 5V  
V
= 5V  
V
= 20V  
OUT  
OUT  
IN  
A: Output pin voltage 10V/div  
B: Output pin current 1A/div  
C: Inductor current 0.5A/div  
D: Output ripple voltage 20 mV/div. AC coupled  
Test Circuits and Layout Guidelines  
Horizontal Time Base: 5µs/div  
FEEDBACK  
+V  
4
2
IN  
V
5.00V  
OUT  
LM2575  
L1  
C
C
— 100µF, 75V Aluminum Electrolytic  
IN  
OUTPUT  
1
— 470µF, 15V Aluminum Electrolytic  
OUT  
D1 — Schottky, MBR360  
7V - 40V  
UNREGULATED  
DC INPUT  
330 µH  
+
100 µF  
L1 — 330µH, 415-0926 (AIE)  
R1 — 1k, 0.01%  
+
R2  
R1  
C
OUT  
470µF  
L
GND  
3
ON/OFF  
5
O
A
D
D1  
MBR360  
R2 — 3.065k, 0.01%  
5-pin TO-220 socket—2936 (Loranger Mfg. Co.)  
4-pin TO-3 socket—8112-AG7 (Augat Inc.)  
C
IN  
FEEDBACK  
OUTPUT  
+V  
4
2
IN  
V
5.00V  
OUT  
LM2575-5.0  
L1  
C
C
— 100µF, 75V Aluminum Electrolytic  
IN  
1
— 330µF, 15V Aluminum Electrolytic  
OUT  
D1 — Schottky, MBR360  
L1 — 330µH, 415-0926 (AIE)  
5-pin TO-220 socket—2936 (Loranger Mfg. Co.)  
4-pin TO-3 socket—8112-AG7 (Augat Inc.)  
7V - 40V  
UNREGULATED  
DC INPUT  
330 µH  
+
100 µF  
+
C
OUT  
220µF  
L
GND  
3
ON/OFF  
5
O
A
D
D1  
MBR360  
C
IN  
Note: Pin numbers are for TO-220 Package  
Figure 1.  
As in any switching regulator, layout is very important. Rapidly switching currents associated with wiring inductance generate voltage transients  
which can cause problems. For minimal stray inductance and ground loops, the length of the leads indicated by heavy lines should be kept as  
short as possible. Single-point grounding (as indicated) or ground plane construction should be used for best results.  
Block Diagrams  
INTERNAL  
INTERNAL  
V
V
IN  
IN  
ON/OFF  
5
ON/OFF  
ON/OFF  
5
ON/OFF  
1
4
1
4
REGULATOR  
REGULATOR  
FEED-  
BACK  
FIXED GAIN  
ERROR AMP  
FIXED GAIN  
ERROR AMP  
3.1k  
1.0k  
FEED-  
BACK  
1 AMP  
SWITCH  
1 AMP  
SWITCH  
COMPARATOR  
COMPARATOR  
+
-
+
-
+
-
+
-
DRIVER  
DRIVER  
2
3
2
3
OUTPUT  
GND  
OUTPUT  
GND  
1.23V  
BAND-GAP  
REFERENCE  
1.23V  
BAND-GAP  
REFERENCE  
52 kHz  
OSCILLATOR  
THERMAL  
SHUTDOWN  
CURRENT  
LIMIT  
52 kHz  
OSCILLATOR  
THERMAL  
SHUTDOWN  
CURRENT  
LIMIT  
RESET  
RESET  
Note: Pin numbers are for the TO-220 package  
Fixed Regulator  
Adjustable Regulator  
August 1999  
7
M2575  

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MICREL

LM2575-3.3BWMT&R

Switching Regulator, Voltage-mode, 3.2A, 63kHz Switching Freq-Max, BIPolar, PDSO24, SOIC-24
MICREL

LM2575-3.3BWMT&R

Switching Regulator, Voltage-mode, 3.2A, 63kHz Switching Freq-Max, BIPolar, PDSO24, SOIC-24
MICROCHIP

LM2575-3.3D2T

Easy Switcher 1.0 A Step-Down Voltage Regulator(389.50 k)
ETC

LM2575-3.3MDC

IC 3.2 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, UUC, DIE, Switching Regulator or Controller
NSC

LM2575-3.3MWC

IC 3.2 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, UUC, WAFER, Switching Regulator or Controller
NSC

LM2575-3.3T

Easy Switcher 1.0 A Step-Down Voltage Regulator(389.50 k)
ETC

LM2575-3.3TA5R

1.0A Step - Down Voltage Switching Regulators 1A output current
FCI