MIC2544/2548
Programmable Current Limit
High-Side Switch
General Description
The MIC2544 and MIC2548 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 MIC2544/48 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 MIC2544/48’s open-drain flag output is used to
indicate current-limiting or thermal shutdown to a local
controller. The MIC2548 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 MIC2548.
The MIC2544 and MIC2548 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”)
75μA 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 (MIC2548)
2ms (slow) turn-on and 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
_________________________________________________________________________________________________________
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.
MIC2544/2548
Ordering Information*
Part Number
MIC2544-1BM
MIC2544-1BMM
MIC2544-2BM
MIC2544-2BM
MIC2544-1YM
MIC2544-1YMM
MIC2544-2YM
MIC2544-2YMM
MIC2548-1BM
MIC2548-1BMM
MIC2548-2BM
MIC2548-2BMM
MIC2548-1YM
MIC2548-1YMM
MIC2548-2YM
MIC2548-2YMM
Enable
Active High
Active High
Active Low
Active Low
Active High
Active High
Active Low
Active Low
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
-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
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
2
M9999-043010
Micrel, Inc.
MIC2544/2548
Pin Configuration
8-pin SOIC (M)
8-Pin MSOP (MM)
Note: Pins 4 and 5 for SOIC and MSOP are different.
Pin Description
Pin Number
MSOP-8
1
Pin Number
SOIC-9
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.
MIC2548 only: Also resets thermal shutdown latch.
Fault Flag (Output): Active-low, open-drain output. Indicates overcurrent
or thermal shutdown conditions. MIC2548 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
3
M9999-043010
Micrel, Inc.
MIC2544/2548
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) ....................................................+7.0V
Output Voltage (V
OUT
) .................................................+7.0V
Output Current (I
OUT
) .................................Internally Limited
Enable Input (V
EN
) .................................. –0.3V to VIN+0.3V
Fault Flag Voltage (V
FLG
).............................................+7.0V
Fault Flag Current (I
FLG
) ..............................................50mA
Storage Temperature (T
s
) .........................–65°C to +150°C
Junction Temperature (T
J
) ........................Internally Limited
Lead Temperature (soldering, 5 sec.)........................ 260°C
ESD Rating
(3)
.................................................................. 2kV
Operating Ratings
(2)
Supply Voltage (V
IN
)..................................... +2.7V to +5.5V
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.
Symbol
Parameter
Supply Current
V
EN
Enable Input Voltage
Enable Input Capacitance
R
DS(on)
Switch Resistance
Current Limit Factor
Output Leakage Current
t
ON
T
R
T
OFF
T
F
Output Turn-On Delay
Output Turn-On Rise Time
Output Turn-Off Delay
Output Turn-Off Fall Time
Overtemperature Threshold Shutdown
Error Flag Output Resistance
Error Flag Off Current
EN Pulse Reset Width
V
IN
to EN Set-Up
Current-Limit Response Time
Overcurrent Flag Response Time
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 MIC2544-1 and MIC2548-1. Off is
≥2.4V
and on is
≤0.8V
for the MIC2544-2 and MIC2548-2. 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
Condition
Switch off, OUT = open
(4)
Switch on, OUT = open
(4)
Enable high
(4)
Enable low
(1)
Note 5
I
OUT
= 500mA
I
OUT
= 100mA to 1A, V
OUT
=1V to 4V
(6)
I
OUT
= 500mA to 1.5A, V
OUT
=1V to 4V
Switch off
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
T
J
increasing
T
J
decreasing
V
IN
= 5V, I
L
= 10μA
V
IN
= 3.3V, I
L
= 10μA
V
FLG
= 5V
MIC2548 thermal shutdown latch
MIC2548
(6)
(6)
Min
#
2.4
Typ
0.75
75
1.7
1.5
1
80
Max
5
160
0.8
120
276
299
10
5
5
Units
μA
μA
V
V
pF
mΩ
V
V
μA
ms
ms
μs
μs
°C
°C
184
161
1
1
230
230
1
2
2
22
21
140
130
4
5
0.01
15
20
1
Ω
Ω
μA
μs
μs
5
0
25
5
V
OUT
= 0V
(6)
V
OUT
= V
IN
/2 to FLG low
μs
μs
April 2010
4
M9999-043010
Micrel, Inc.
MIC2544/2548
Test Circuit
Functional Characteristics Test Circuit
Timing Diagrams
Figure 1a. MIC2544/48-1
Figure 1b. MIC2544/48-2
April 2010
5
M9999-043010
单片机
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