MIC2544A/2548A
Programmable Current Limit
High-Side Switch
General Description
The MIC2544A and MIC2548A 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 MIC2544A/48A 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 current-limit,
protects the switch and the attached device.
The MIC2544A/48A’s open-drain flag output is used to
indicate current-limiting or thermal shutdown to a local
controller. The MIC2548A 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 MIC2548A
The MIC2544A and MIC2548A are available in active-high
and active-low enable versions in the 8-pin SOIC
(small-outline integrated circuit) and 8-pin MSOP (micro-
small-outline package).
Features
•
•
•
•
•
•
•
•
•
•
•
2.7V to 5.5V input
Adjustable current-limit up to 1.5A
Reverse current flow blocking (no “body diode”)
90µA typical on-state supply current
1μA typical off-state supply current
120mΩ maximum on-resistance
Open-drain fault flag
Thermal shutdown
Thermal shutdown output latch (MIC2548A)
2ms (slow) turn-on and fast turn-off
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
_________________________________________________________________________________________________________
Typical Application
Typical Advanced Configuration and Power Interface (ACPI) 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
April 2010
M9999-043010
Micrel, Inc.
MIC2544A/2548A
Ordering Information*
Part Number
MIC2544A-1YM
MIC2544A-1YMM
MIC2544A-2YM
MIC2544A-2YMM
MIC2548A-1YM
MIC2548A-1YMM
MIC2548A-2YM
MIC2548A-2YMM
Enable
Active High
Active High
Active Low
Active Low
Active High
Active High
Active Low
Active Low
Latch*
Temperature Range
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
Package
8-pin SOIC
8-pin MSOP
8-pin SOIC
8-pin MSOP
8-pin SOIC
8-pin MSOP
8-pin SOIC
8-pin MSOP
Pb-Free
*Thermal Shutdown Latch
April 2010
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M9999-043010
Micrel, Inc.
MIC2544A/2548A
Pin Configuration
8-pin SOIC
8-Pin MSOP (MM)
Note:
1.
Pins 4 and 5 for SOIC and MSOP are different.
Pin Description
Pin Number
MSOP-8
1
Pin Number
SOIC-8
1
Pin Name
EN
Pin Function
Enable (Input): Logic-compatible enable input. Active-high (-1) or active-
low (-2). High input >1.7V typical; low input <1.5V typical. Do not float.
MIC2548A only: Also resets thermal shutdown latch.
Fault Flag (Output): Active-low, open-drain output. Indicates over current
or thermal shutdown conditions. MIC2548A only: latched low on thermal
shutdown.
Ground.
Current Limit: Sets current-limit threshold using an external resistor, R
SET
1
connected to ground. 154Ω < R
SET
< 2.29kΩ.
Input: Output MOSFET drain. Also powers internal circuitry.
Switch (Output): Output MOSFET source. Pins 6 and 8 must be externally
connected.
Not internally connected.
2
3
5
7
6,8
4
2
3
4
7
6,8
5
FLG
GND
ILIM
IN
OUT
NC
April 2010
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M9999-043010
Micrel, Inc.
MIC2544A/2548A
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) ....................................... –0.3V to 6.0V
Output Voltage (V
OUT
) ....................................... –0.3V to V
IN
Output Current (I
OUT
) .................................Internally Limited
Enable Input (V
EN
) ................................... –0.3V to V
IN
+0.3V
Fault Flag Voltage (V
FLG
)................................... –0.3V to 6V
Fault Flag Current (I
FLG
) ..............................................50mA
Storage Temperature (T
s
) .........................–65°C to +150°C
Junction Temperature (T
J
) ........................Internally Limited
Lead Temperature (soldering, 10 sec.)...................... 260°C
ESD Rating
(3)
.................................................................. 2kV
Operating Ratings
(2)
Supply Voltage (V
IN
)..................................... +2.7V to +5.5V
Enable Voltage (V
EN
).............................................. 0V to V
IN
Current Limit Set Range................................... 0.1A to 1.5A
Ambient Temperature (T
A
) .......................... –40°C to +85°C
Package Thermal Resistance
SOIC (θ
JA
) ........................................................160°C/W
MSOP (θ
JA
) ......................................................206°C/W
Electrical Characteristics
V
IN
= +5V; T
A
= 25°C,
Bold
values indicate –40°C to +85°C, unless noted.
Parameter
Condition
Min
Typ
Max
Units
Power Input Supply
Input Voltage Range (V
IN
)
Shutdown Current
Supply Current
Switch off, V
OUT
= Open
(4)
Switch on, V
OUT
= Open
(4)
2.7
0.75
90
5.5
5
160
V
µA
µA
Enable Input
EN Logic Level High
EN Logic Level Low
En Bias Current
EN Input Capacitance
EN Pulse Reset Width
V
IN
to EN Set-Up
V
EN
= 2.4V
(4)
V
EN
= 0.8V
(4)
(Note 5)
MIC2548 Thermal Shutdown Latch
(5)
MIC2548
(5)
5
0
2.4
1.7
1.5
0.1
0.1
1
0.8
1.0
1.0
V
V
µA
µA
pF
µs
µs
Internal Switch
On Resistance R
DS(ON)
Output Leakage Current
I
OUT
= 500mA
Switch off
80
1
120
10
mΩ
µA
Current Limit
Current Limit Factor
I
OUT
= 100mA to 500mA, V
OUT
= 1V to 4V
(6)
I
OUT
= 500mA to 1.5A, V
OUT
= 1V to 4V
Current-Limit Response
Time
V
OUT
= 0V
(5) (6)
(6)
161
184
230
230
25
299
276
V
V
µs
Output Response Times
Output Turn-On Delay
Output Turn-On Rise Time
Output Turn-Off Delay
Output Turn-Off Fall Time
R
L
= 10Ω, C
L
= 1µF, Figures 1a, 1b
R
L
= 10Ω, C
L
= 1µF, Figures 1a, 1b
R
L
= 10Ω, C
L
= 1µF, Figures 1a, 1b
R
L
= 10Ω, C
L
= 1µF, Figures 1a, 1b
1
1
2
2
30
30
5
5
ms
ms
µs
µs
April 2010
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M9999-043010
Micrel, Inc.
Error Flag
Error Flag Output
Resistance
Error Flag Off Current
V
IN
= 5V, I
L
= 10µA
V
IN
= 3.3V, I
L
= 10µA
V
FLG
= 5.0V
7
9
0.01
15
20
1
MIC2544A/2548A
Ω
Ω
µA
Thermal Protection
Over-temperature Shutdown
Over-temperature Shutdown
Hysteresis
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. Off is
≤0.8V
and on is
≥2.4V
for the MIC2544A-1 and MIC2548A-1. Off is
≥2.4V
and on is
≤0.8V
for the MIC2544A-2 and MIC2548A-2. The enable
input has about 200mV of hysteresis.
5. Guaranteed by design but not production tested.
6. Current limit threshold is determined by I
LIMIT
= 230V , where R
SET
is in ohms.
R
SET
T
J
Rising
150
5
°C
°C
April 2010
5
M9999-043010
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