MIC4574BWM Micrel Semiconductor, MIC4574BWM Datasheet

no-image

MIC4574BWM

Manufacturer Part Number
MIC4574BWM
Description
200kHz Simple 0.5A Buck Voltage Regulator
Manufacturer
Micrel Semiconductor
Datasheet
MIC4574
General Description
The MIC4574 is a series of easy to use fixed and adjustable
BiCMOS step-down (buck) switch-mode voltage regulators.
The 200kHz MIC4574 duplicates the pinout and function of
the 52kHz LM2574. The higher switching frequency may
allow up to a 2:1 reduction in output filter inductor size.
The MIC4574 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 0.5A 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
conditions. The oscillator frequency is guaranteed to 10%.
In shutdown mode, the regulator draws less than 200 A
standby current.
current limiting and thermal shutdown for protection under
fault conditions.
This series of simple switch-mode regulators requires a
minimum number of external components and can operate
using a standard series of inductors. Frequency compensa-
tion is provided internally.
The MIC4574 is available in DIP (N) and SOIC (WM) pack-
ages for the industrial temperature range.
Typical Applications
3% for fixed versions, within specified voltages and load
The regulator performs cycle-by-cycle
6V to 24V
Shutdown
Enable
10µF
35V
C1
8V to 24V
Shutdown
Enable
10
5
47µF
35V
C1
SHDN
V
SGND
IN
MIC4574BWM
4
3
5
SHDN
V
PGND
MIC4574-5.0BN
IN
SGND
Adjustable Regulator
SW
6
FB
2
Fixed Regulator
12
3
PGND
4-92
4
SW
FB
D1
MBRS130LT3
100µH
Features
• Fixed 200kHz operation
• 3.3V, 5V, and adjustable output versions
• Voltage over specified line and load conditions:
• Guaranteed 0.5A switch current
• Wide 4V to 24V input voltage range
• Wide 1.23V to 20V output voltage range
• Requires minimum external components
• < 200 A typical shutdown mode
• 75% efficiency (adjustable version > 75% typ.)
• Standard inductors and capacitors are
• Thermal shutdown
• Overcurrent protection
• 100% electrical thermal limit burn-in
Applications
• Simple high-efficiency step-down (buck) regulator
• Efficient preregulator for linear regulators
• On-card switching regulators
• Positive-to-negative converter (inverting buck-boost)
• Isolated flyback converter using minimum external
• Negative boost converter
L1
200kHz Simple 0.5A Buck Voltage Regulator
7
1
25% of typical LM2574 values
components
Fixed version: 3% max. output voltage
Adjustable version: 2% max. feedback voltage
D1
1N5819
100µH
R2
2.49k
1%
R1
1.50k
1%
L1
5.0V/0.5A
C3
3300pF
C2
220µF
16V
MIC4574
3.3V/0.5A
C2
330µF
6.3V
April 1998•
Micrel

Related parts for MIC4574BWM

MIC4574BWM Summary of contents

Page 1

... Isolated flyback converter using minimum external components • Negative boost converter 3 7 SHDN SW MIC4574-5.0BN SGND PGND 47µ 35V Fixed Regulator SHDN SW 100µH MIC4574BWM SGND PGND MBRS130LT3 Adjustable Regulator 4-92 MIC4574 L1 5.0V/0.5A 100µH C2 220µF 16V D1 1N5819 3.3V/0. 2.49k 3300pF ...

Page 2

... MIC4574 Ordering Information Part Number MIC4574-3.3BN MIC4574-5.0BN MIC4574BN MIC4574-3.3BWM MIC4574-5.0BWM MIC4574BWM Pin Configuration FB 1 SGND 2 SHDN 3 PGND 4 8-Pin DIP (N) Pin Description Pin Number Pin Number Pin Name N Package WM Package SGND 3 5 SHDN 4 6 PGND April 1998• Voltage Temperature Range 3.3V – ...

Page 3

MIC4574 Absolute Maximum Ratings Supply Voltage (V ) Note 1 ....................................... +40V IN Shutdown (V ) ....................................... –0.3V to +36V SHDN Output Switch (V ) steady state ................................. –1V SW Junction Temperature (T ) ...................................... +150 C J Storage Temperature ...

Page 4

MIC4574 Block Diagrams Shutdown Enable SHDN MIC4574-x.x Shutdown Enable SHDN MIC4574 April 1998• +24V max Internal Regulator Thermal Current Shutdown Limit 200kHz Oscillator Driver Com- parator 0.5A Switch 1.23V Bandgap Error Amp GND Block Diagram with ...

Page 5

MIC4574 Functional Description The MIC4574 is a variable duty cycle switch-mode regulator with an internal power switch. Refer to the block diagrams. Supply Voltage The MIC4574 operates from a +4V to +24V unregulated input. Highest efficiency operation is from a ...

Page 6

... D1 MBRS130LT3 Sanyo 35CV168GX, ESR = 0.34 C2 Sanyo 16CV470GX, ESR = 0.17 D1 Motorola MBRS130LT3 L1 Coilcraft DO3316P-104, DCR = 0.23 Low-Cost Surface Mount L1 12 SHDN SW 220µH R2 MIC4574BWM 13. SGND PGND R1 D1 1.50k 4 6 SS16 1% UUX1H470MNT1GS, ESR = 0.4 16CV470GX, ESR = 0.17 DO3316-224, DCR = 0.53 Low-Cost Surface Mount ...

Related keywords