MIC2544/2548
Micrel
MIC2544/2548
Programmable Current Limit High-Side Switch
Preliminary Information
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 Con-
figuration 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 resis-
tor-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 SOP (small-outline
package) and 8-pin MSOP (micro-small-outline package).
Features
•
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•
•
•
•
•
•
•
•
•
•
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•
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
USB power distribution
PCI Bus Power Switching
Notebook PC
ACPI power distribution
PC card hot swap applications
Inrush current-limiting
Applications
Typical Application
+5V
R
FLG
On/Off
MIC2544-xBM
EN
FLG
GND
ILIM
R
SET
OUT
IN
OUT
NC
0.1µF
33µF
Peripheral
SOP pinout shown
Typical Advanced Configuration and Power Interface (ACPI) Application
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
June 2000
1
MIC2544/2548
MIC2544/2548
Micrel
Ordering Information
Part Number
MIC2544-1BM
MIC2544-1BMM
MIC2544-2BM
MIC2544-2BMM
MIC2548-1BM
MIC2548-1BMM
MIC2548-2BM
MIC2548-2BMM
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 SOP
8-pin MSOP
8-pin SOP
8-pin MSOP
8-pin SOP
8-pin MSOP
8-pin SOP
8-pin MSOP
* Thermal Shutdown Latch
Pin Configuration
MIC2544/2548
EN
FLG
GND
ILIM
1
2
3
4
8
7
6
5
OUT
IN
OUT
NC
EN
FLG
GND
NC
1
2
3
4
MIC2544/2548
8
7
6
5
OUT
IN
OUT
ILIM
8-Pin SOP (M)
MIC2544/2548
(OUT)
(EN)
(FLG)
LOGIC,
CHARGE
PUMP
8-Pin MSOP (MM)
NOTE: PINS 4 AND 5
FOR SOIC AND MSOP
ARE DIFFERENT.
(IN)
(ILIM)
(GND)
Pin Description
Pin Number
MSOP-8
1
Pin Number
SOP-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.
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
,
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
2
FLG
3
5
7
6,8
4
3
4
7
6,8
5
GND
ILIM
IN
OUT
NC
MIC2544/2548
2
June 2000
MIC2544/2548
Micrel
Absolute Maximum Ratings
(Note 1)
Supply Voltage (V
IN
) .................................................. +6.0V
Output Voltage (V
OUT
) ............................................... +6.0V
Output Current (I
OUT
) ............................... Internally Limited
Enable Input (V
EN
) ................................. –0.3V to V
IN
+0.3V
Fault Flag Voltage (V
FLG
) ........................................... +6.0V
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,
Note 3
...................................................... 2kV
Operating Ratings
(Note 2)
Supply Voltage (V
IN
) ................................... +2.7V to +5.5V
Current Limit Set Range .................................. 0.1A to 1.5A
Ambient Temperature Range (T
A
) ............. –40°C to +85°C
Package Thermal Resistance
SOP
(θ
JA
) .......................................................... 160°C/W
MSOP
(θ
JA
) ....................................................... 206°C/W
Electrical Characteristics
V
IN
= +5V; T
A
= 25°C,
bold
indicates –40°C to +85°C; unless noted
Symbol
Parameter
Supply Current
Condition
switch off, OUT = open,
Note 4
switch on, OUT = open,
Note 4
V
EN
Enable Input Voltage
enable high,
Note 4
enable low,
Note 1
Enable Input Current
V
EN
= V
OH(min)
= 2.4V
V
EN
= V
OL(max)
= 0.8V
Enable Input Capacitance
R
DS(on)
Switch Resistance
Current Limit Factor
Note 6
I
OUT
= 500mA
I
OUT
= 100mA to 1A, V
OUT
= 1V to 4V,
Note 5
I
OUT
= 500mA to 1.5A, V
OUT
= 1V to 4V,
Note 5
Output Leakage Current
t
ON
t
R
t
OFF
t
F
Output Turn-On Delay
Output Turn-On Rise Time
Output Turnoff Delay
Output Turnoff Fall Time
Overtemperature Threshold
Shutdown
Error Flag Output Resistance
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
Error Flag Off Current
EN Pulse Reset Width
V
IN
to EN Set-Up
Current-Limit Response Time
Overcurrent Flag Response Time
Note 1.
Note 2.
Note 3.
Note 4.
Min
Typ
0.75
75
Max
5
160
Units
µA
µA
V
2.4
1.7
1.5
0.01
0.01
1
80
120
276
299
10
5
5
0.8
1
1
V
µA
µA
pF
mΩ
V
V
µA
ms
ms
µs
µs
°C
°C
Ω
Ω
µA
µs
µs
µs
µs
184
161
230
230
1
1
1
2
2
22
21
140
130
4
5
0.01
15
20
1
V
FLG
= 5V
MIC2548 thermal shutdown latch
MIC2548,
Note 6
V
OUT
= 0V,
Note 6
V
OUT
= V
IN
/2 to FLG low
5
0
25
5
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating rating.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
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.
230V
Current limit threshold is determined by
I
LIMIT
=
R
, where R
SET
is in ohms.
SET
Note 5.
Note 6.
Guaranteed by design but not production tested.
June 2000
3
MIC2544/2548
MIC2544/2548
Micrel
Test Circuit
V
OUT
Device
Under OUT
Test
I
OUT
R
L
C
L
t
r
V
OUT
10%
90%
90%
10%
t
f
Functional Characteristics Test Circuit
Timing Diagrams
50%
t
OFF
t
ON
V
OUT
90%
10%
V
EN
Figure 1a. MIC2544/48-1
V
EN
50%
t
OFF
t
ON
V
OUT
90%
10%
Figure 1b. MIC2544/48-2
MIC2544/2548
4
June 2000
MIC2544/2548
Micrel
Output Reset
EN
V
OUT
I
LIMIT
I
DC
I
OUT
FLG
Short-Circuit Fault
Fault Removed
Thermal Shutdown
Reached
Figure 2a. MIC2548-2 Timing: Output is reset by toggling EN
EN
V
OUT
I
LIMIT
I
DC
I
OUT
FLG
Short-Circuit
Fault
Fault
Removed
Thermal Shutdown
Reached
Figure 2b. MIC2544-2 Timing
June 2000
5
MIC2544/2548
测试/测量
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