MIC4575-3.3WUTR [MICROCHIP]
3.2A SWITCHING REGULATOR, 220kHz SWITCHING FREQ-MAX, PSSO5, ROHS COMPLIANT, TO-263, 5 PIN;
| 型号： | MIC4575-3.3WUTR |
| 厂家： | 
MICROCHIP |
| 描述： | 3.2A SWITCHING REGULATOR, 220kHz SWITCHING FREQ-MAX, PSSO5, ROHS COMPLIANT, TO-263, 5 PIN 信息通信管理 开关 |
| 文件： | 总15页 (文件大小：525K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC4575
200kHz Simple 1A Buck Regulator
General Description
Features
The MIC4575 is a series of easy to use fixed and
adjustable BiCMOS step-down (buck) switch-mode voltage
regulators. The 200kHz MIC4575 duplicates the pinout
and function of the 52kHz LM2575. The higher switching
frequency may allow up to a 2:1 reduction in output filter
inductor size.
• Fixed 200kHz operation
• 3.3V, 5V, 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 switch current
• Wide 4V to 24V input voltage range
• Wide 1.23V to 20V output voltage range
• Requires minimum external components
• < 200µA typical shutdown mode
• 75% efficiency (adjustable version > 75% typical)
• Standard inductors and capacitors are25% of typical
LM2575 values
• Thermal shutdown
The MIC4575 is available in 3.3V, and 5V fixed output
versions or a 1.23V to 20V adjustable output version. Both
versions are capable of driving a 1A load with excellent
line and load regulation.
The feedback voltage is guaranteed to ±2% tolerance for
adjustable versions, and the output voltage is guaranteed
to ±3% for fixed versions, within specified voltages and
load conditions. The oscillator frequency is guaranteed to
±10%.
In shutdown mode, the regulator draws less than 200µA
standby current. The regulator performs cycle-by-cycle
current limiting and thermal shutdown for protection under
fault conditions.
• Overcurrent protection
• 100% electrical thermal limit burn-in
Applications
This series of simple switch-mode regulators requires a
minimum number of external components and can operate
using a standard series of inductors. Frequency comp-
ensation is provided internally.
• Simple high-efficiency step-down (buck) regulator
• Efficient pre-regulator for linear regulators
• On-card switching regulators
• Positive-to-negative converter (inverting buck-boost)
• Battery charger
The MIC4575 is available in TO-220 (T) and TO-263 (U)
packages for the industrial temperature range.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
• Negative boost converter
• Step-down 6V to 3.3V for Intel Pentium® and similar
microprocessors
___________________________________________________________________________________________________________
Typical Application
L1
5.0V/1A
Shutdown
Enable
5
2
4
SHDN
MIC4575-5.0_T
VIN FB
SW
68µH
8V to 24V
1
C2
330µF
16V
C1
150µF
35V
GND
D1
1N5819
3
Fixed Regulator
Adjustable Regulator
Pentium is a registered trademark of Intel Corporation
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
M9999-072909
July 2009
1
Micrel, Inc.
MIC4575
Ordering Information
Part Number
Voltage
3.3V
5.0V
Adj.
Temperature Range
–40° to +85°C
–40° to +85°C
–40° to +85°C
–40° to +85°C
–40° to +85°C
–40° to +85°C
Package
Standard
RoHS Compliant*
MIC4575-3.3BT
MIC4575-5.0BT
MIC4575BT
MIC4575-3.3WT
MIC4575-5.0WT
MIC4575WT
5-Pin TO-220
5-Pin TO-220
5-Pin TO-220
5-Pin TO-263
5-Pin TO-263
5-Pin TO-263
MIC4575-3.3BU
MIC4575-5.0BU
MIC4575BU
MIC4575-3.3WU
MIC4575-5.0WU
MIC4575WU
3.3V
5.0V
Adj.
* RoHS compliant with ‘high-melting solder’ exemption.
Pin Configuration
5
4
3
2
1
SHDN
FB
GND
SW
VIN
5-Pin TO-220 (T)
5-Pin TO-263 (U)
Pin Description
Pin Number
Pin Name
Pin Function
Supply Voltage (Input): Unregulated +4V to +40V supply voltage.
1
2
IN
SW
Switch (Output): Emitter of NPN output switch. Connect to external storage
inductor and Shottky diode.
3, TAB
4
GND
FB
Ground.
Feedback (Input): Output voltage feedback to regulator. Connect to output of
supply for fixed versions. Connect to 1.23V tap of resistive divider for adjustable
versions.
5
SHDN
Shutdown (Input): Logic low enables regulator. Logic high (> 2.4V) shuts down
regulator.
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Micrel, Inc.
MIC4575
Absolute Maximum Ratings
Operating Ratings
Supply Voltage (VIN)(1) ..................................................+40V
Shutdown Voltage (VSHDN)............................. –0.3V to +36V
Output Switch (VSW) .......................................................–1V
Storage Temperature (Ts) ...........................–65°C to 150°C
ESD(2)
Supply Voltage (VIN).....................................................+24V
Junction Temperature (TJ) ....................................... +150°C
Package Thermal Resistance
TO-220, TO-263 (θJA) ........................................65°C/W
TO-220, TO-263 (θJC)..........................................2°C/W
Electrical Characteristics(4)
VIN = 12V; ILOAD = 200mA; TJ = 25°C, bold values indicate –40°C< TJ < +85°C, unless noted.
Parameter
Condition
Min
Typ
Max
Units
MIC4575 [Adjustable]
Feedback Voltage
Feedback Voltage
1.217
1.230
1.230
1.243
V
8V ≤ VIN ≤ 24V, 0.2A ≤ ILOAD ≤ 1A
1.193
1.180
1.267
1.280
V
V
Efficiency
ILOAD = 1A, VOUT = 5V
77
50
%
Feedback Bias Current
100
500
nA
nA
MIC4575-3.3
Output Voltage
Output Voltage
3.234
3.3
3.3
3.366
V
6V ≤ VIN ≤ 24V, 0.2A ≤ ILOAD ≤ 1A
3.168
3.135
3.432
3.465
V
V
Efficiency
ILOAD = 1A
72
%
MIC4575-5.0
Output Voltage
Output Voltage
4.900
5.0
5.0
5.100
V
8V ≤ VIN ≤ 24V, 0.2A ≤ ILOAD ≤ 1A
4.800
4.750
5.200
5.250
V
V
Efficiency
ILOAD = 1A
77
%
MIC4575 / -3.3 / -5.0
Oscillator Frequency
Saturation Voltage
180
90
200
1
220
kHz
IOUT = 1A
1.3
1.5
V
V
Maximum Duty Cycle (On)
Current Limit
FB connected to 0V
95
%
Peak Current, tON ≤ 3µs
1.7
1.3
2.2
3.0
3.2
A
A
Output Leakage Current
VIN = 24V, FB connected to 0V
Output = 0V
0
7.5
2
35
mA
mA
Output = –1V
Quiescent Current
5
10
mA
µA
Standby Quiescent Current
SHDN Input Logic Level
SHDN = 5V (regulator off)
VOUT = 0V (regulator off)
50
1.4
200
2.2
2.4
V
V
SHDN Input Current
VOUT = 3.3 or 5V (regulator on)
1.2
1.0
0.8
V
V
SHDN = 5V (regulator off)
SHDN = 0V (regulator on)
4
0.01
30
10
µA
µA
–10
Notes:
1. The MIC4575 is not guaranteed to survive a short circuit to ground for input voltage above 24V.
2. Devices are ESD sensitive. Handling precautions recommended.
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July 2009
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Micrel, Inc.
MIC4575
Functional Diagram
Block Diagram with External Components
Fixed Step-Down Regulator
⎝
⎜
⎛
⎛
⎜
⎝
⎝
⎜
⎛
⎛
⎜
⎝
Block Diagram with External Components
Adjustable Step-Down Regulator
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Micrel, Inc.
MIC4575
A higher feedback voltage increases the error amplifier
Functional Description
The MIC4575 is a variable duty cycle switch-mode
regulator with an internal power switch. Refer to the
block diagrams.
output voltage.
A
higher error amplifier voltage
(comparator inverting input) causes the comparator to
detect only the peaks of the sawtooth, reducing the duty
cycle of the comparator output. A lower feedback voltage
increases the duty cycle.
Supply Voltage
The MIC4575 operates from a +4V to +24V unregulated
input. Highest efficiency operation is from a supply
voltage around +15V.
Output Switching
When the internal switch is on, an increasing current
flows from the supply VIN, through external storage
inductor L1, to output capacitor COUT and the load.
Energy is stored in the inductor as the current increases
with time.
Enable/Shutdown
The shutdown (SHDN) input is TTL compatible. Ground
the input if unused. A logic-low enables the regulator. A
logic-high shuts down the internal regulator which
reduces the current to typically 50µA.
When the internal switch is turned off, the collapse of the
magnetic field in L1 forces current to flow through fast
recovery diode D1, charging COUT
.
Feedback
Output Capacitor
Fixed versions of the regulator have an internal resistive
divider from the feedback (FB) pin. Connect FB directly
to the output line.
External output capacitor COUT provides stabilization and
reduces ripple.
Adjustable versions require an external resistive voltage
divider from the output voltage to ground, connected
from the1.23V tap to FB.
Return Paths
During the on portion of the cycle, the output capacitor
and load currents return to the supply ground. During the
off portion of the cycle, current is being supplied to the
output capacitor and load by storage inductor L1, which
means that D1 is part of the high-current return path.
Duty Cycle Control
A fixed-gain error amplifier compares the feedback
signal with a 1.23V bandgap voltage reference. The
resulting error amplifier output voltage is compared to a
200kHz sawtooth waveform to produce a voltage
controlled variable duty cycle output.
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Micrel, Inc.
MIC4575
Application Information
The applications circuits that follow have been
constructed and tested. Refer to Application Note 15 for
additional information, including efficiency graphs and
manufacturer’s addresses and telephone numbers for
most circuits.
For a mathematical approach to component selection
and circuit design, refer to Application Note 14.
Figure 4. 6V–24V to 3.3V/1A Buck Converter
Low-Profile Surface Mount
Figure 1. 6V–24V to 3.3V/1A Buck Converter
Through Hole
Figure 5. 8V–24V to 5V/1A Buck Converter
Low-Profile Surface Mount
Figure 2. 8V–24V to 5V/1A Buck Converter
Through Hole
Figure 6. 16V–24V to 12V/1A Buck Converter
Low-Profile Surface Mount
L1
12V/1A
5
1
2
4
SHDN
SW
FB
150µH
R2
13.0k
1%
MIC4575BT
16V to 24V
C2
330µF
16V
VIN
C1
68µF
63V
GND
3
R1
1.50k
1%
MBR160
C1 Nichicon
C2 Nichicon
D1 Motorola MBR160
L1 Sumida
Figure 3. 16V–24V to 12V/1A Buck Converter
Through Hole
Figure 7. 6V–24V to 3.3V/1A Buck Converter
Lower-Cost Surface Mount
Note 2: Surface-mount component.
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July 2009
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Micrel, Inc.
MIC4575
Figure 8. 8V–24V to 5V/1A Buck Converter
Figure 10. 8V–18V to –5V/0.2A Buck-Boost Converter
Through Hole
Lower-Cost Surface Mount
Figure 9. 16V–24V to 12V/1A Buck Converter
Lower-Cost Surface Mount
Figure 11. 5V to –5V/0.3A Buck-Boost Converter
Through Hole
VOUT
5V/1A
T1
L1
68µH
5
1
2
4
4
1
3
2
SHDN
MIC4575BU
VIN
SW
FB
1µH
R2
3.01k
1%
5mVP-P
VIN
8V to 18V
C3
3300pF
C2
220µF
10V
C1
22µF
35V
GND
3
R1
1.00K
1%
C4
220µF
10V
D1
MBRS130LT3
C1 AVX
C2 AVX
C4 AVX
D1 Motorola MBRS130LT3
T1 Coiltronics
L1 Coilcraft DO1608C-102
Figure 12. Low Output-Noise Regulator (5mV Output Ripple )
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July 2009
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Micrel, Inc.
MIC4575
+VOUT/+IOUT
5V/0.5A
T1
68µH
5
1
2
4
2
1
SHDN
MIC4575BU
VIN
SW
FB
R2
3.01k
1%
VIN
8V to 18V
C3
3300pF
C2
220µF
10V
C1
22µF
35V
GND
3
R1
1.00K
1%
D1
MBRS130LT3
4
3
C5
220µF
10V
C4
220µF
10V
L1
D2
MBRS130LT3
-VOUT/-IOUT
-5V/0.5A
at VIN 15V
+I
+ –I
+V
V
A
+ 0.5V
– 0.5V
C1 AVX
C2 AVX
C4 AVX
C5 AVX
D1 Motorola MBRS130LT3
D2 Motorola MBRS130LT3
T1 Coiltronics
DC
Load Regulation 5%
40% then – I
40% then – I
× (1 – DC)
Figure 13. Split ±5V Supply
Figure 14. Adjustable (0V–12V) Output-Voltage Regulator
U1
L1
68µH
VOUT
1V/1A
5
1
2
4
SHDN
MIC4575BT
VIN
SW
FB
VIN
4V to 15V
3
2
1
U2
LM358
GND
3
C2
330µF
16V
R3
1k
C1
150µF
35V
D1
1N5819
R1
R2
249
1%
1.00k
1%
C1
C2
D1 Motorola 1N5819
L1
U2 National LM358
Figure 15. Low Output-Voltage Regulator (1V)
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July 2009
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Micrel, Inc.
MIC4575
Figure 16. 1A Battery Charger (6–8 cells)
D3
1N4148
L1
68µH
D2
1N5819
IOUT
0.1A to 1A
R1
0.1
5
1
2
4
SHDN
MIC4575-BT
VIN
SW
VIN
8V to 24V
D1
1N5819
R6
3k
C2
330µF
16V
2-8 Cells
VBATT
R2
FB
100
VIN
1%
C4
1000pF
GND
3
C1
150µF
35V
3
R5
10k
U2A
1/2LM358
1
R7
1k
R3
10k
VIN
U2B
1/2 LM358
2
8
U1 Micrel
MIC4575BT
5
VR1
10k
U3
U2 National LM358
C3
LM4041CIZ-1.2
7
U3 Micrel
LM4041CIZ-1.2
C1 Nichicon
6
C2 Nichicon
DZ1
1N5244
14V
Q1
0.01µF
4
D1 Motorola 1N5819
D2 Motorola 1N5819
D3 Motorola 1N4148
L1 Coiltronics
VN2222LL
R1 KRL
Q1 Siliconix VN2222LL
SP-1-A1-0R100J
R4
1.21k
1%
V
/ 0.9 + 2.5V
Figure 17. 0.1A–1A Variable-Current Battery Charger
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July 2009
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Micrel, Inc.
MIC4575
Figure 18. 1A Battery Charger (2–8 Cells)
Figure 19. Remote-Sensing Regulator
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July 2009
10
Micrel, Inc.
MIC4575
Figure 20. 6V–18V to Split ±12V/100mA Supply
Figure 21. 1A Battery Charger
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July 2009
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Micrel, Inc.
MIC4575
⎝
⎜
⎛
⎛
⎜
⎝
Figure 22. Improved Adjustable Output-Voltage Regulator (0V–12V)
Figure 23. Switchable Battery-Pack Charger
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July 2009
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Micrel, Inc.
MIC4575
⎝
⎜
⎛
⎛
⎜
⎝
Figure 24. Lithium-Ion Battery Charger with End-of-Charge Flag
⎝
⎜
⎛
⎛
⎜
⎝
Figure 25. Low Output-Noise Regulator (<1mV)
M9999-072909
July 2009
13
Micrel, Inc.
MIC4575
Package Information
5-Pin TO-220 (T)
5-Pin TO-263 (U)
M9999-072909
July 2009
14
Micrel, Inc.
MIC4575
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its
use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant
into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 1997 Micrel, Incorporated.
M9999-072909
July 2009
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