MIC2168_05 Datasheet, PDF (1/14 Pages) Micrel Semiconductor – 1MHz PWM Synchronous Buck Control IC

MIC2168
MIC2168
Micrel, Inc.
1MHz PWM Synchronous Buck Control IC
General Description
The MIC2168 is a high-efficiency, simple to use 1MHz PWM
synchronous buck control IC housed in a small MSOP-10
package. The MIC2168 allows compact DC/DC solutions
with a minimal external component count and cost.
The MIC2168 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 MIC2168 senses current across the high-side N-Chan-
nel MOSFET, eliminating the need for an expensive and
lossy current-sense resistor. Current limit accuracy is main-
tained 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 MIC2168 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
• 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
Applications
• Point-of-load DC/DC conversion
• Set-top boxes
• Graphic cards
• LCD power supplies
• Telecom power supplies
• Networking power supplies
• Cable modems and routers
Typical Application
V_IN = 5V
100µF
SD103BWS
4.7µF
0.1µF
VDD
BST
1kΩ
CS
100pF
100nF
VIN
HSD
MIC2168
VSW
COMP/EN
LSD
4kΩ
GND ^FB
IRF7821
1.2µH
IRF7821
3.3V
10kΩ
3.24kΩ
150µF x 2
MIC2168 Adjustable Output 1MHz Converter
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
April 2005
1
M9999-040805