MIC2174_10 Datasheet, PDF (1/27 Pages) Micrel Semiconductor – Synchronous Buck Controller Featuring Adaptive On-Time Control 40V Input, 300kHz

MIC2174/MIC2174C
Synchronous Buck Controller
Featuring Adaptive On-Time Control
40V Input, 300kHz
Hyper Speed Control™ Family
General Description
Features
The Micrel MIC2174/MIC2174C is a fixed-frequency,
synchronous buck controller featuring adaptive on-time
control. The MIC2174/MIC2174C operates over an input
supply range of 3V to 40V at a fixed switching frequency of
300kHz and is capable of driving 25A of output current.
The output voltage is adjustable down to 0.8V.
A unique Hyper Speed Control™ architecture allows for
ultra-fast transient response while reducing the output
capacitance. It also makes ultra-fast transient response
while reducing the output capacitance and also allows for
extremely low duty-cycle operation. The MIC2174 /
MIC2174C utilizes an adaptive T_ON ripple controlled
architecture. A UVLO is provided to ensure proper
operation under power-sag conditions to prevent the
external power MOSFET from overheating. A soft-start is
provided to reduce inrush current. Foldback current limit
and “hiccup” mode short-circuit protection ensure FET and
load protection.
The MIC2174/MIC2174C is available in a 10-pin MSOP
(MAX1954A-compatible) package with an operating
junction temperature range from –40°C to +125°C.
• Hyper Speed Control™ architecture enables:
– High delta V operation (V_HSD = 40V and V_OUT = 0.8V)
– Smaller output capacitors than competitors
• 3V to 40V input voltage
• Any Capacitor^TM stable
- Zero ESR to high ESR
• 300kHz switching frequency
• Adjustable output from 0.8V to 5.5V (V_HSD ≤ 28V)
• Adjustable output from 0.8V to 3.6V (V_HSD > 28V)
• ±1% FB accuracy (MIC2174)
• ±3% FB accuracy (MIC2174C)
• Up to 94% efficiency
• Foldback current limit and “hiccup” mode short-circuit
protection
• Thermal shutdown
• Safe start-up into pre-biased loads
• –40°C to +125°C junction temperature range
Applications
All support documentation can be found on Micrel’s web
site at: www.micrel.com.
• Telecom Networking
• Industrial Equipment
• Distributed DC power systems
____________________________________________________________________________________________________________
Typical Application
Synchronous Buck Controller Featuring Adaptive On-Time Control
100
95
90
85
80
75
70
65
60
55
50
0
12V to 3.3V Efficiency
VIN=5V
2
4
6
8
10
OUTPUT 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
September 2010
M9999-091310-C