MIC26903ZA Datasheet, PDF (1/28 Pages) Micrel Semiconductor – 28V, 9A Hyper Speed Control Synchronous DC/DC Buck Regulator

MIC26903-ZA
28V, 9A Hyper Speed Control
Synchronous DC/DC Buck Regulator
SuperSwitcher II
General Description
The Micrel MIC26903-ZA is a constant-frequency,
synchronous buck regulator featuring a unique adaptive
on-time control architecture. The MIC26903-ZA operates
over an input supply range of 4.5V to 28V and provides a
regulated output of up to 9A of output current. The output
voltage is adjustable down to 0.6V with a guaranteed
accuracy of ±1%, and the device operates at a switching
frequency of 600kHz.
Micrel’s Hyper Speed Control architecture allows for
ultra-fast transient response while reducing the output
capacitance and also makes (High V_IN)/(Low V_OUT)
operation possible. This adaptive t_ON ripple control
architecture combines the advantages of fixed-frequency
operation and fast transient response in a single device.
The MIC26903-ZA offers a full suite of 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, foldback current limit, “hiccup mode” short-circuit
protection, and thermal shutdown. An open-drain Power
Good (PG) pin is provided.
Datasheets and support documentation are available on
Micrel’s web site at: www.micrel.com.
Features
• Hyper Speed Control architecture enables
− High Delta V operation (V_IN = 28V and V_OUT = 0.6V)
− Small output capacitance
• 4.5V to 28V voltage input
• 9A output current capability, up to 95% efficiency
• Adjustable output from 0.6V to 5.5V
• ±1% feedback accuracy
• Any Capacitor stable - zero-to-high ESR
• 600kHz switching frequency
• No external compensation
• Power Good (PG) output
• Foldback current-limit and “hiccup mode” short-circuit
protection
• Supports safe startup into a pre-biased load
• –40°C to +125°C junction temperature range
• 28-pin 5mm × 6mm QFN 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
55
50
0
Efficiency (V_IN = 12V)
vs. Output Current
5.0V
3.3V
2.5V
1.8V
1.5V
1.2V
1.0V
0.9V
V_IN = 12V
2
4
6
8
10
12
OUTPUT CURRENT (A)
Hyper Speed Control, SuperSwitcher II, 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
May 29, 2013
Revision 1.0