MIC4684 Datasheet, PDF (1/16 Pages) Micrel Semiconductor – 2A High-Efficiency SuperSwitcher Buck Regulator

MIC4684
Micrel
MIC4684
2A High-Efficiency SuperSwitcher™ Buck Regulator
Final Information
General Description
Features
The MIC4684 is a high-efficiency 200kHz stepdown (buck)
switching regulator. Power conversion efficiency of above
85% is easily obtainable for a wide variety of applications.
The MIC4684 achieves 2A of continuous current in an 8-lead
SO (small outline) package at 60°C ambient temperature.
High efficiency is maintained over a wide output current range
by utilizing a boost capacitor to increase the voltage available
to saturate the internal power switch. As a result of this high
efficiency, no external heat sink is required. The MIC4684,
housed in an SO-8, can replace larger TO-220 and TO-263
packages in many applications.
The MIC4684 allows for a high degree of safety. It has a wide
input voltage range of 4V to 30V (34V transient), allowing it to
be used in applications where input voltage transients may be
present. Built-in safety features include over-current protec-
tion, frequency-foldback short-circuit protection, and thermal
shutdown.
The MIC4684 is available in an 8-lead SO package with a
junction temperature range of –40°C to +125°C.
• SO-8 package with 2A continuous output current
• Over 85% efficiency
• Fixed 200kHz PWM operation
• Wide 4V to 30V input voltage range
• Output voltage adjustable to 1.235V
• All surface mount solution
• Internally compensated with fast transient response
• Over-current protection
• Frequency foldback short-circuit protection
• Thermal shutdown
Applications
• Simple high-efficiency step-down regulator
• 5V to 3.3V/1.7A converter (60°C ambient)
• 12V to 1.8V/2A converter (60°C ambient)
• On-card switching regulator
• Dual-output ±5V converter
• Battery charger
Ordering Information
Part Number
MIC4684BM
Voltage Junction Temperature Range
Adj
–40°C to +125°C
Package
SOP-8
Typical Application
V_IN
6.5V to 25V
C_IN
33µF
35V
MIC4684BM
C_BS
3 _VIN
BS ^{4 0.33µF/50V}
8 _EN
SW ¹
FB ⁵
GND
2, 6, 7
68µH
3A
40V
R1
3.01k
R2
3.01k
V_OUT
2.5V/1.5A
330µF
6.3V
Adjustable Buck Converter
V_IN
5V
±10%
C_IN
68µF
10V
1A, 20V Feed forward diode
MIC4684BM
3 _VIN
BS ⁴
8 _EN
SW ¹
FB ⁵
GND
2, 6, 7
C_BS
0.33µF/50V
47µH
2A
20V
V_OUT
3.3V/1.7A
220µF
10V
Efficiency
vs. Output Current
100
V_OUT = 3.3V
80
60 _{VOUT = 1.8V}
40
V_OUT = 2.5V
20 V = 5.0V
IN
0
0
0.5
1
1.5
2
OUTPUT CURRENT (A)
Efficiency vs. Output Current
5V to 3.3V Converter
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
July 2001
1
MIC4684