MIC26950_11 Datasheet, PDF (1/28 Pages) Micrel Semiconductor – 12A Hyper Speed ControlTM Synchronous DC-DC Buck Regulator

MIC26950
12A Hyper Speed Control^TM
Synchronous DC-DC Buck Regulator
SuperSwitcher II^TM
General Description
The Micrel MIC26950 is a constant-frequency, synchronous
buck regulator featuring a unique digitally modified adaptive
ON-time control architecture. The MIC26950 operates over
an input supply range of 4.5V to 26V and provides a
regulated output at up to 12A of output current. The output
voltage is adjustable down to 0.8V with a typical accuracy of
±1%, and the device operates at a switching frequency of
300kHz.
Micrel’s Hyper Speed Control^TM architecture allows for ultra-
fast transient response while reducing the output capacitance
and also makes (High V_IN)/(Low V_OUT) operation possible.
This digitally modified adaptive t_ON ripple control architecture
combines the advantages of fixed-frequency operation and
fast transient response in a single device.
The MIC26950 offers a full suite of protection features to
ensure protection of the IC during fault conditions. These
include undervoltage lockout to ensure proper operation
under power-sag conditions, internal soft-start to reduce
inrush current, fold-back current limit, “hiccup” mode short-
circuit protection and thermal shutdown.
All support documentation can be found on Micrel’s web
site at: www.micrel.com.
Features
• Hyper Speed Control^TM architecture enables
- High delta V operation (V_IN = 26V and V_OUT = 0.8V)
- Small output capacitance
• 4.5V to 26V input voltage
• Adjustable output from 0.8V to 5.5V (±1% accuracy)
• Any Capacitor^TM Stable
- Zero-ESR to high-ESR output capacitance
• 12A output current capability
• 300kHz switching frequency
• Internal compensation
• Up to 95% efficiency
• 6ms internal soft-start
• Foldback current-limit and “hiccup” mode short-circuit
protection
• Thermal shutdown
• Supports safe start-up into a pre-biased load
• –40°C to +125°C junction temperature range
• 28-pin 5mm X 6mm MLF^® package
Applications
• Distributed power systems
• Communications/networking infrastructure
• Set-top box, gateways and routers
• Printers, scanners, graphic cards and video cards
____________________________________________________________________________________________________________
Typical Application
100
95
90
85
80
75
70
65
60
0
Efficiency (VIN = 12V)
vs. Output Current
5.0V
3.3V
2.5V
1.5V
1.0V
3
6
9
12
15
OUTPUT CURRENT (A)
Hyper Speed Control, SuperSwitcher II and Any Capacitor are trademarks of Micrel, Inc.
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
July 2011
M9999-070111-C