MIC4682 Datasheet, PDF (1/15 Pages) Micrel Semiconductor – PRECISION CURRENT LIMIT SO-8 SUPERSWITCHER BUCK REGULATOR

MIC4682
Micrel
MIC4682
Precision Current Limit SO-8 SuperSwitcher™ Buck Regulator
General Description
The MIC4682 is an easy-to-use step-down (buck) switch-
mode voltage regulator. It features a programmable current
limit that allows 10% current limit accuracy over its full
operating temperature range. The precision current limit
makes the MIC4682 ideal for constant-voltage constant-
current applications, such as simple battery chargers. The
precision current limit also gives designers the ability to set
the maximum output current below the saturation current
rating of the inductor. This allows the use of the smallest
possible inductors for a given application, saving valuable
space and cost.
The MIC4682 is a very robust device. Its 4V to 34V input
voltage range allows the MIC4682 to safely be used in
applications where voltage transients may be present. Addi-
tional protection features include cycle-by-cycle current lim-
iting and over-temperature shutdown. The MIC4682 is avail-
able in a thermally optimized power SO-8 package that allows
it to achieve 2A of continuous output current.
The MIC4682 requires a minimum number of external com-
ponents and can operate using a standard series of induc-
tors. Compensation is provided internally for fast transient
response and ease of use. The MIC4682 is available in the 8-
lead power SOP with a –40°C to +125°C junction tempera-
ture range.
Features
• Programmable output current limit
• 10% accuracy over temperature
• Wide 4V to 34V operating input voltage range
• Fixed 200kHz PWM operation
• Power SO-8 package allows 2A continuous output
current
• All surface mount solution
• Internally compensated
• Less than 1µA typical shutdown-mode current
• Thermal shutdown protection
Applications
• Battery chargers
• White LED drivers
• Constant voltage constant current step-down converters
• Simple step-down regulator with precise current limit
• USB power supplies
Typical Application
+7.5V to +34V
C1
10µF
50V
(x2)
MIC4682
5 _IN
SW ⁸
4 _SHDN
R3
10M
ISET
3
FB ¹
GND
2, 6, 7
R4
16.2k
L1
68µH
D1
B240
R1
3.01k
R2
976Ω
5V/1A
C2
220µF
10V
MIC4682 Current Limit
Characteristics
6
5
4
3
2
1
V_IN = 12V
00
0.5
1
1.5
2
CURRENT LIMIT (A)
Constant Current/Constant Voltage Li Ion Battery Charger
SuperSwitcher is a trademark of Micrel, Inc.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
October 2003
1
M0334-102203