MIC2124 Datasheet, PDF (1/24 Pages) Micrel Semiconductor – Constant Frequency, Synchronous Current Mode Buck Controller

MIC2124
Constant Frequency, Synchronous
Current Mode Buck Controller
Hyper Speed Control™ Family
General Description
The Micrel MIC2124 is a member of the Hyper Speed
Contro™l family of DC-DC controllers. It uses an adaptive
on-time current mode control scheme and operates at a
constant frequency.
The MIC2124 operates over a supply range of +3V to
+18V, and is independent of the IC supply voltage V_IN. It
operates at a fixed 300kHz switching frequency and can
be used to provide up to 25A of output current. The output
voltage is adjustable down to +0.8V.
The MIC2124 includes an EN/COMP pin that can be
pulled low to shut down the converter. The MIC2124
optimizes performance and ensures stability with external
compensation.
The UVLO is provided to ensure proper operation under
power-sag conditions and to make sure that the external
power MOSFET has enough voltage to work with. An
internal digital soft-start ensures reduced inrush current.
Cycle-by-cycle current limiting ensures FET protection.
The MIC2124 is available in a 10-pin MSOP package with
a junction temperature operating range from –40ºC to
+125ºC.
Features
• +3V to +18V input voltage
• 25A output current capability
• Any Capacitor^TM stable
- Zero ESR to high ESR
• Output down to 0.8V with ±1% FB accuracy
• Up to 94% efficiency
• 300kHz switching frequency
• All N-Channel MOSFET design
• Shutdown feature with EN/COMP
• No current-sense resistor needed
• Internal 4ms digital soft-start
• Thermal shutdown
• Pre-bias output safe
• Cycle-by-Cycle foldback current-limit protection
• 10-pin MSOP package
• –40ºC to +125ºC junction temperature range
Applications
• Printers and scanners
• Graphic and video cards
• PCs and servers
• Microprocessor core supply
• Low-voltage distributed power
• Telecommunication and networking
• Set-top box, gateways and router
Typical Application
12V to 3.3V Efficiency
100
90
80
MIC2124 Adjustable Output 300kHz Buck Converter
70
60
0
VHSD = 12V
VIN = 5V
2
4
6
8
10
O UT PUT CURRENT (A)
Hyper Speed Control and Any Capacitor are trademarks of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
June 2010
M9999-060810-D