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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
advanced 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
indicate 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.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com
.
Features
• 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
Applications
• USB power distribution
• PCI Bus Power Switching
• Notebook PC
• ACPI power distribution
• PC card hot swap applications
• Inrush current-limiting
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Typical Application
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
June 2011
M9999-062711-A
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