MIC2169B Datasheet, PDF (1/24 Pages) Micrel Semiconductor – 500kHz PWM Synchronous Buck Control IC

MIC2169B
500kHz PWM Synchronous Buck
Control IC
General Description
Features
The MIC2169B is a high-efficiency, simple to use 500kHz
PWM synchronous buck control IC housed in a small
MSOP-10 ePad package. It allows compact DC/DC
solutions with a minimal external component count and
cost. The device features high output driver capability to
drive loads up to 30A.
• 3V to 14.5V input voltage range
• Adjustable output voltage down to 0.8V
• 500kHz PWM operation
• Up to 95% efficiency
• Output Pre-biased Protection
The MIC2169B 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 within the smallest possible
printed circuit board space area.
The MIC2169B 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 MIC2169B is identical to the
MIC2169A except it supports pre-bias loads. Internal pre-
bias circuit prevents output voltage drooping and
excessive reverse inductor current when powering up with
a pre-bias voltage at the output.
• Build-in 2.2Ω drivers to drive two N-channel MOSFETs
• Adaptive gate drive increases efficiency
• Simple voltage-mode PWM control with externally
compensated
• Short minimum ON time of 30ns allowing very low duty
cycle
• Fast transient response
• Adjustable current limit senses high-side N-Channel
MOSFET current
• Hiccup mode short-circuit protection
• No external current-sense resistor
• Internal soft-start current source
• Dual function COMP and EN pin allows low-power
shutdown
• Available in a small size 10-pin MSOP ePad package
The MIC2169B is available in a thermally capable 10-pin
ePad 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.
Applications
• Point-of-load DC/DC conversion
• High Current Power Supplies
• Telecom/Datacom and Networking Power Supplies
• Servers and Workstations
• Graphic cards and other PC Peripherals
• Set-top boxes
• LCD power supplies
___________________________________________________________________________________________________________
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
June 2009
M9999- 060309-A
[phone]