January 2005
1
M0512-112603
MIC2042/2043
Micrel
MIC2042/2043
Single Channel, High Current, Low Voltage,
Protected Power Distribution Switch
General Description
The MIC2042 and MIC2043 are high-side MOSFET switches
optimized for general purpose power distribution applications
which require circuit protection. The devices switch up to 5.5V
and as low as 0.8V while offering both programmable current
limiting and thermal shutdown to protect the device and the
load. A fault status output is provided in order to detect
overcurrent and thermal shutdown fault conditions. Both
devices employ soft-start circuitry to minimize the inrush
current in applications that employ highly capacitive loads.
Additionally, for tighter control over inrush current during
start-up, the output slew-rate may be adjusted by an external
capacitor.
The MIC2043 features a auto-reset circuit breaker mode that
latches the output off upon detecting an overcurrent condition
lasting more than 28ms. The output is reset by removing or
reducing the load.
All support documentation can be found on Micrel’s web
site at www.micrel.com.
Typical Application
Features
• 60m
Ω
max. on-resistance
• 0.8V to 5.5V operating range
• Adjustable current limit
• Power-Good detection
• Up to 3A continuous output current
• Short-circuit protection with thermal shutdown
• Adjustable slew-rate control
• Circuit breaker mode (MIC2043)
• Fault status flag
• Undervoltage lockout
• Output MOSFET reverse current flow block when
disabled
• Very fast reaction to short-circuits
• Low quiescent current
Applications
• Docking stations
• Notebook PCs
• PDAs
• Hot swap board insertions
• RAID controllers
• USB hosts
• ACPI power distribution
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
8, 12
7
2
3
6
9
13
10,11,14
1
4
R
SET
200
Ω
Note:
All V
IN
pins (8, 12) must be externally tied together.
All V
OUT
pins (10, 11, 14) must be externally tied together.
I
LIMIT
≅
2A.
Output Power-Good = 3.0V.
*C4 is optional. See
"Applications Information."
C4*
0.022
µ
F
C1
0.1
µ
F
Logic
Controller
ON/OFF
OVERCURRENT
IN
5
MIC2042-1BTS
MIC39100-2.5BS
VBIAS
VIN
EN
/FAULT
ILIM
SLEW
2.5V
VOUT
PGREF
PWRGD
UVLOIN
GND
+3.3V
Power
Supply
R1
20k
Ω
R4
20k
Ω
R2
294k
Ω
1%
R3
24.3k
Ω
1%
EN
IN
GND
OUT
C
LOAD
33
µ
F
(OPEN)
V
OUT
3.3V@ 1.5A
OUT1
OUT2
C2
0.1
µ
F
C3
4.7
µ
F
