MIC29311
3A Fast-Response LDO Regulator for
USB
General Description
The MIC29311 is a 3A, fast response, low-dropout (LDO)
voltage regulator. Using Micrel’s proprietary Super
βeta
PNP™ process, the MIC29311 offers exceptional dropout
(600mV at 3A) and low ground current (60mA at 3A). Fast
transient response allows it to recover quickly from large
load changes while maintaining a steady output. The
device can be sent into a “zero-current” off mode when the
TTL compatible enable is brought low.
Designed specifically for Universal Serial Bus (USB)
applications, the MIC29311 works with USB power
switches to provide an economical solution for self-
powered hubs. The 5.1V output voltage is optimized to
work with lower-cost high on-resistance USB power
switches (300mΩ) to provide a minimum of 4.75V at
500mA to downstream ports. Used with MIC2527 quad
USB power switches, the MIC29311 can power up to 6
downstream ports.
Features of the MIC29311 include thermal shutdown,
current limit, reversed-battery and reversed-lead insertion
protection. An overvoltage clamp is available to maintain a
safe output when the input voltage exceeds 8V. An error
flag is also available to indicate of the output falls out of
regulation, or when an overcurrent condition occurs.
The MIC29311 is available in a 5-pin TO-220 or TO-263
package with a fixed 5.1V output voltage.
For other high current, low-dropout voltage regulators,
please see the MIC29150/300/500/750 and the MIC29310,
MIC29510, MIC29710.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
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Fast transient response
3A output current over full temperature range
600mV dropout voltage at full load
Low ground current
3% total accuracy
“Zero” off-mode current
Thermal Shutdown
Current Limiting
Reversed battery protection
Fixed 5.1V Output
Applications
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Self-powered USB hubs
USB power switching
High-efficiency linear power supplies
High-efficiency switching supply post-regulator
Ordering Information
Part Number
Standard
MIC29311-5.1BT
RoHS Compliant*
MIC29311-5.1WT
Voltage
5.1V
Temperature Range
0° to +125°C
Package
TO-220-5
* RoHs compliant with ‘high-melting solder’ exemption.
Super ßeta PNP is a trademarks of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
September 2007
M9999-090507
MICREL [ MICREL SEMICONDUCTOR ]
