MIC2182
Micrel
MIC2182
High-Efficiency Synchronous Buck Controller
General Description
Micrel’s MIC2182 is a synchronous buck (step-down) switch-
ing regulator controller. An all N-channel synchronous archi-
tecture and powerful output drivers allow up to a 20A output
current capabilty. The PWM and skip-mode control scheme
allows efficiency to exceed 95% over a wide range of load
current, making it ideal for battery powered applications, as
well as high current distributed power supplies.
The MIC2182 operates from a 4.5V to 32V input and can
operate with a maximum duty cycle of 86% for use in low-
dropout conditions. It also features a shutdown mode that
reduces quiescent current to 0.1µA.
The MIC2182 achieves high efficiency over a wide output
current range by automatically switching between PWM and
skip mode. Skip-mode operation enables the converter to
maintain high efficiency at light loads by turning off circuitry
pertaining to PWM operation, reducing the no-load supply
current from 1.6mA to 600µA. The operating mode is inter-
nally selected according to the output load conditions. Skip
mode can be defeated by pulling the PWM pin low which
reduces noise and RF interference.
The MIC2182 is available in a 16-pin SOP (small-outline
package) and SSOP (shrink small-outline package) with an
operating range from –40°C to +85°C.
Features
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4.5V to 32V Input voltage range
1.25V to 6V Output voltage range
95% efficiency
300kHz oscillator frequency
Current sense blanking
5Ω impedance MOSFET Drivers
Drives N-channel MOSFETs
600µA typical quiescent current (skip-mode)
Logic controlled micropower shutdown (I
Q
< 0.1µA)
Current-mode control
Cycle-by-cycle current limiting
Built-in undervoltage protection
Adjustable undervoltage lockout
Easily synchronizable
Precision 1.245V reference output
0.6% total regulation
16-pin SOP and SSOP packages
Frequency foldback overcurrent protection
Sustained short-circuit protection at any input voltage
20A output current capability
DC power distribution systems
Notebook and subnotebook computers
PDAs and mobile communicators
Wireless modems
Battery-operated equipment
Applications
Typical Application
V
IN
4.5V to 30V*
R7
100k
D2
MIC2182-3.3BSM
10
11
SD103BWS
VIN
VDD
C5
0.1µF
6
2
BST
EN/UVLO HSD
PWM
VSW
LSD
14
16
15
13
12
8
9
7
C6
0.1µF
C9
4.7µF
16V
C11
22uf
35V
x2
Q2*
Si4884
Q1*
Si4884
L1
10µH
D1
B140
V
OUT
3.3V/4A
C7
220uf
10V
×2
GND
R2
0.02Ω
C4
1nF
1
3
SS
COMP
SYNC
PGND
CSH
VOUT
VREF
SGND
4
C3
0.1µF
C2
2.2nF
GND
R1
2k
5
C13, 1nF
* 30V maximum input voltage limit is due
to standard 30V MOSFET selection.
C1
0.1µF
See “Application Information” section for
5V to 3.3V/10A and other circuits.
4.5V–30V* to 3.3V/4A Converter
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
April 22, 2004
1
M9999-042204
MICREL [ MICREL SEMICONDUCTOR ]
