MIC2545A/2549A
Micrel
MIC2545A/2549A
Programmable Current Limit High-Side Switch
General Description
The MIC2545A and MIC2549A are integrated high-side
power switches optimized for low loss DC power switching
and other power management applications, including Ad-
vanced Configuration and Power Interface (ACPI). The
MIC2545A/49A is a cost-effective, highly integrated solution
that requires few external components to satisfy USB and
ACPI requirements.
Load current management features include a precision,
resistor-programmable output current-limit and a soft-start
circuit, which minimizes inrush current when the switch is
enabled. Thermal shutdown, along with adjustable current-
limit, protects the switch and the attached device.
The MIC2545A/49A’s open-drain flag output is used to indi-
cate current-limiting or thermal shutdown to a local controller.
The MIC2549A has an additional internal latch which turns
the output off upon thermal shutdown, providing robust fault
control. The enable signal is compatible with both 3V and 5V
logic, and is also used as the thermal shutdown latch reset for
the MIC2549A.
The MIC2545A and MIC2549A are available in active-high
and active-low enable versions in 8-pin DIP, SOIC, and
TSSOP packages.
Features
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2.7V to 5.5V input
Adjustable current-limit up to 3A
Reverse current flow blocking
90µA typical on-state supply current
1µA typical off-state supply current
50mΩ maximum on-resistance
Open-drain fault flag
Thermal shutdown
Thermal shutdown output latch (MIC2549A)
2ms (slow) soft-start turn-on, fast turnoff
Available with active-high or active-low enable
USB power distribution
PCI Bus Power Switching
Notebook PC
ACPI power distribution
PC card hot swap applications
Inrush current-limiting
Applications
Typical Application
+5V
10k
On/Off
MIC2545A
EN
FLG
GND
ILIM
R
SET
OUT
IN
OUT
IN
0.1µF
33µF
Peripheral
Typical Advanced Configuration and Power Interface (ACPI) Application
UL Recognized Component
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
April 2004
1
M9999-041204
MICREL [ MICREL SEMICONDUCTOR ]
