MIC2168A
1MHz PWM Synchronous Buck Control IC
General Description
The MIC2168A is a high-efficiency, simple to use 1MHz PWM
synchronous buck control IC housed in a small MSOP-10
package. The MIC2168A allows compact DC/DC solutions
with a minimal external component count and cost.
The MIC2168A operates from a 3V to 14.5V input, without
the need of any additional bias voltage. The output voltage
can be precisely regulated down to 0.8V. The adaptive all
N-Channel MOSFET drive scheme allows efficiencies over
95% across a wide load range.
The MIC2168A senses current across the high-side N-
Channel MOSFET, eliminating the need for an expensive
and lossy current-sense resistor. Current limit accuracy is
maintained by a positive temperature coefficient that tracks
the increasing R
DS(ON)
of the external MOSFET. Further cost
and space are saved by the internal in-rush-current limiting
digital soft-start.
The MIC2168A is available in a 10-pin MSOP package, with
a wide junction operating range of –40°C to +125°C.
All support documentation can be found on Micrel’s web site
at www.micrel.com.
Features
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3V to 14.5V input voltage range
Adjustable output voltage down to 0.8V
Up to 95% efficiency
1MHz PWM operation
Adjustable current-limit senses high-side N-Channel
MOSFET current
No external current sense resistor
Adaptive gate drive increases efficiency
Ultra-fast response with hysteretic transient recovery
mode
Overvoltage protection protects the load in fault
conditions
Dual mode current limit speeds up recovery time
Hiccup mode short-circuit protection
Internal soft-start
Dual function COMP and EN pin allows low-power shut-
down
Small size MSOP 10-lead package
Point-of-load DC/DC conversion
Set-top boxes
Graphic cards
LCD power supplies
Telecom power supplies
Networking power supplies
Cable modems and routers
Applications
Typical Application
V
IN
= 5V
100µF
4.7µF
0.1µF
VDD
VIN
BST
CS
1kΩ
IRF7821
1.2µH
IRF7821
10kΩ
150µF x 2
3.24kΩ
SD103BWS
100
95
90
85
80
75
3.3V
MIC2168 Efficiency
HSD
MIC2168A
VSW
LSD
FB
2Ω
1000nF
100pF
4kΩ
100nF
COMP/EN
70
65
60
55
50
V
IN
= 5V
V
OUT
= 3.3V
0
2
4
6
I
LOAD
(A)
8
10
GND
MIC2168A Adjustable Output 1MHz Converter
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
April 2005
1
M9999-062205
MICREL [ MICREL SEMICONDUCTOR ]
