MIC2545A.pdf

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MIC2545A/2549A
Micrel
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 Ad-
vanced 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 indi-
cate 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.
Features
• 2.7V to 5.5V input
• Adjustable current-limit up to 3A
• Reverse current flow blocking
• 90
A typical on-state supply current
A typical off-state supply current
• 50m
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
Typical Application
+5V
10k
MIC2545A
On/Off
EN
FLG
GND
ILIM
OUT
IN
OUT
IN
Peripheral
R SET
0.1µF
33µF
Typical Advanced Configuration and Power Interface (ACPI) Application
UL Recognized Component
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
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MIC2545A/2549A
Micrel
Ordering Information
Part Number
Enable
Latch*
Temperature Range
Package
Pb-Free
MIC2545A-1BM
Active High
–40 ° C to +85 ° C
8-lead SOP
MIC2545A-1BN
Active High
–40 ° C to +85 ° C
8-pin DIP
MIC2545A-1BTS
Active High
–40
C to +85
C
14-lead TSSOP
MIC2545A-2BM
Active Low
–40 ° C to +85 ° C
8-lead SOP
MIC2545A-2BN
Active Low
–40 ° C to +85 ° C
8-pin DIP
MIC2545A-2BTS
Active Low
–40 ° C to +85 ° C
14-lead TSSOP
MIC2545A-1YM
Active High
–40
C to +85
C
8-lead SOP
MIC2545A-1YN
Active High
–40 ° C to +85 ° C
8-pin DIP
MIC2545A-1YTS
Active High
–40 ° C to +85 ° C
14-lead TSSOP
MIC2545A-2YM
Active Low
–40 ° C to +85 ° C
8-lead SOP
MIC2545A-2YN
Active Low
–40
C to +85
C
8-pin DIP
MIC2545A-2YTS
Active Low
–40 ° C to +85 ° C
14-lead TSSOP
MIC2549A-1BM
Active High
–40 ° C to +85 ° C
8-lead SOP
MIC2549A-1BN
Active High
–40 ° C to +85 ° C
8-pin DIP
MIC2549A-1BTS
Active High
–40
C to +85
C
14-lead TSSOP
MIC2549A-2BM
Active Low
–40 ° C to +85 ° C
8-lead SOP
MIC2549A-2BN
Active Low
–40 ° C to +85 ° C
8-pin DIP
MIC2549A-2BTS
Active Low
–40 ° C to +85 ° C
14-lead TSSOP
MIC2549A-1YM
Active High
–40
C to +85
C
8-lead SOP
MIC2549A-1YN
Active High
–40 ° C to +85 ° C
8-pin DIP
MIC2549A-1YTS
Active High
–40 ° C to +85 ° C
14-lead TSSOP
MIC2549A-2YM
Active Low
–40 ° C to +85 ° C
8-lead SOP
MIC2549A-2YN
Active Low
–40
C to +85
C
8-pin DIP
MIC2549A-2YTS
Active Low
–40 ° C to +85 ° C
14-lead TSSOP
Pin Configuration
MIC2545A/2549A
MIC2545A/2549A
EN
1
8
OUT
EN
1
14
OUT
FLG
2
7
IN
NC
2
13
NC
GND
3
6
OUT
FLG
3
12
IN
ILIM
4
5
IN
NC
4
11
NC
8-Lead SOP (M)
8-Pin DIP (N)
GND
5
10
OUT
NC
6
9
NC
ILIM
7
8 IN
MIC2545A/2549A
(EN) 1
(FLG) 2
LOGIC,
CHARGE
PUMP
6,8 (OUT)
14-Lead TSSOP (TS)
5,7 (IN)
(ILIM) 4
3 (GND)
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April 2004
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MIC2545A/2549A
Micrel
Pin Description
Pin Number Pin Number
Pin Name
Pin Function
SOP, DIP
TSSOP
1
1
EN
Enable (Input): Logic-compatible enable input (-1 version is active high, -2
version is active low). High input >1.8V typical; low input <1.4V typical.
Do not float.
MIC2549A only: Also resets thermal shutdown latch.
2
3
FLG
Fault Flag (Output): Active-low, open-drain output. Indicates overcurrent or
thermal shutdown.
MIC2549A only: Latched low on thermal shutdown.
3
5
GND
Ground: Supply return.
4
7
ILIM
Current Limit: Sets current limit threshold using an external resistor (R SET )
connected to ground. 76.8 Ω < R SET < 459 Ω
.
5, 7
8, 12
IN
Supply Input: Output MOSFET drain. Also powers internal circuitry. Both IN
pins must be externally connected together.
6, 8
10, 14
OUT
Switch Output: Output MOSFET source. Both OUT pins must be externally
connected together.
2,4,6,9,11,13
NC
Not internally connected
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MIC2545A/2549A
Micrel
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 +7V
Fault Flag Voltage (V FLG ) ........................................... +7.0V
Fault Flag Current (I FLG ) ............................................ 50mA
Storage Temperature (T S ) ....................... –65
Operating Ratings (2)
Supply Voltage (V IN ) ................................... +2.7V to +5.5V
Ambient Temperature Range (T A ) ............. –40
C to +85
C
Package Thermal Resistance
PDIP
JA ) ......................................................... 130
C/W
SOIC
JA ) ......................................................... 160
C/W
C/W
Current Limit Set Range (5) ................................. 0.5A to 3A
TSSOP
JA ) (4) .................................................. 100
C
Junction Temperature (T J ) ....................... Internally Limited
Lead Temperature (soldering 5 sec.) ........................ 260
C to +150
C
ESD Rating (3) .......................................................................... 2004V
Electrical Characteristics
V IN = +5V; T A = 25 °
C, bold indicates –40 ° C to +85 °
C; unless noted
Symbol
Parameter
Condition
Min
Typ
Max
Units
Supply Current
Switch off, OUT = open (6)
0.75
5
A
Switch on, OUT = open (6)
90
125
A
150
A
V EN
Enable Input Voltage
Enable high transition (6)
2.4
1.6
V
Enable low transition (6)
1.5
0.8
V
Enable Input Current
V EN = V OH(min) = 2.4V
0.01
1
A
V EN = V OL(max) = 0.8V
0.01
1
A
Enable Input Capacitance
Note 7
1
pF
R DS(on)
Switch Resistance
I OUT = 500mA
35
50
m Ω
Current Limit Factor
I LIMIT = 0.5A to 3A, V OUT = 1V to 4V (5)
160
230
300
V
I LIMIT = 1A to 2.5A, V OUT = 1V to 4V (5)
184
230
276
V
Output Leakage Current
Switch off, V OUT = 0V
1
10
A
t ON
Output Turn-On Delay
R L = 10
, C L = 1
F, Figures 1a, 1b
1
2
5
ms
t R
Output Turn-On Rise Time
R L = 10 Ω
, C L = 1 µ
F, Figure 1a, 1b
0.75
1.8
4.9
ms
t OFF
Output Turnoff Delay
R L = 10
, C L = 1
F, Figure 1a, 1b
25
s
t F
Output Turnoff Fall Time
R L = 10 Ω
, C L = 1 µ
F, Figure 1a, 1b
23
s
Overtemperature Threshold
T J increasing
135
C
Shutdown
T J decreasing
120
C
Error Flag Off Current
V FLG = 5V
0.01
1
A
EN Pulse Reset Width
MIC2549A thermal shutdown latch (7)
1
s
t SU
V IN to EN Set-Up
MIC2549A (7) , Figure 1c
0
s
Current-Limit Response Time
V OUT = 0V to I OUT = 2A, I SET = 1A (7)
40
s
V OL
Error Flag Output Resistance
I FLG = 10mA
4
15
Notes:
1. Exceeding the absolute maximum ratings may damage the device.
2. The device is not guaranteed to function outside its operating ratings.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. Assumes 4 layer PCB is used.
I
230
5. Current limit is determined by:
LIMIT
R
, where R SET is in ohms, and 230 is typical current limit factor in volts.
SET
6. Off is
0.8V and on is
2.4V for the MIC2545A-1 and MIC2549A-1. Off is
2.4V and on is
0.8V for the MIC2545A-2 and MIC2549A-2. The
enable input has about 100mV of hysteresis.
7. Guaranteed by design but not production tested.
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April 2004
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MIC2545A/2549A
Micrel
Test Circuit
V OUT
Device
Under
Test
OUT
I OUT
R L
C L
t r
t f
V OUT
90%
90%
10%
10%
Functional Characteristics Test Circuit
Timing Diagrams
V EN
50%
t OFF
t ON
V OUT
90%
10%
Figure 1a. MIC2545A/49A-2
V EN
50%
t OFF
t ON
V OUT
90%
10%
Figure 1b. MIC2545A/49A-1
V IN
t SU
V EN
Figure 1c. Input-to-Enable Setup Timing
April 2004
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