MIC2182 Datasheet, PDF (1/28 Pages) Micrel Semiconductor – High-Efficiency Synchronous Buck Controller Final Information

MIC2182
Micrel
MIC2182
High-Efficiency Synchronous Buck Controller
Final Information
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
• 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
Applications
• DC power distribution systems
• Notebook and subnotebook computers
• PDAs and mobile communicators
• Wireless modems
• Battery-operated equipment
Typical Application
V_IN
4.5V to 30V*
R7
100k
GND
C3
0.1µF
C2
2.2nF
MIC2182-3.3BSM
D2
10 _VIN
VDD ^{11 SD103BWS}
C5
0.1µF
BST ¹⁴
C6
6 _{EN/UVLO HSD} 16
0.1µF
2 _PWM
C4
1nF
VSW ¹⁵
LSD ¹³
1 _SS
PGND ¹²
C11
22uf
35V
C9
x2
4.7µF
16V
Q2*
Si4884
L1
10µH
Q1*
Si4884
D1
B140
R2
0.02Ω
3 _COMP
R1
2k
5 _SYNC
CSH ⁸
VOUT ⁹
VREF ⁷
SGND
4
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.
V_OUT
3.3V/4A
C7
220uf
10V ×2
GND
4.5V–30V* to 3.3V/4A Converter
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
June 2000
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MIC2182