MIC4682_07 Datasheet, PDF (1/15 Pages) Micrel Semiconductor – Precision Current Limit SOIC-8 SuperSwitcher™ Buck Regulator

MIC4682
Precision Current Limit SOIC-8
SuperSwitcher™ Buck Regulator
General Description
Features
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.
Additional protection features include cycle-by-cycle
current limiting and over-temperature shutdown. The
MIC4682 is available in a thermally optimized power
SOIC-8 package that allows it to achieve 2A of continuous
output current.
The MIC4682 requires a minimum number of external
components and can operate using a standard series of
inductors. Compensation is provided internally for fast
transient response and ease of use. The MIC4682 is
available in the 8-pin power SOIC with a –40°C to +125°C
junction temperature range.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
• Programmable output current limit
– 10% accuracy over temperature
• Wide 4V to 34V operating input voltage range
• Fixed 200kHz PWM operation
• Power SOIC-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
976
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. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
June 2007
M9999-061507