MIC2537
Micrel
MIC2537
Quad Power Distribution Switch
Final Information
General Description
The MIC2537 is a cost-effective high-side power switch with
four independently controlled channels, optimized for bus-
powered Universal Serial Bus (USB) applications. Few exter-
nal components are necessary to satisfy USB requirements.
The MIC2537 satisfies the following USB requirements: each
switch channel supplies up to 100mA as required by USB
bus-powered downstream devices; fault current is limited to
typically 250mA, well below the UL 25VA safety require-
ments; and a flag output is available to indicate fault condi-
tions to the local USB controller. Soft start eliminates the
momentary voltage drop on the upstream port that may occur
when the switch is enabled in bus-powered applications.
Additional features include thermal shutdown to prevent
catastrophic switch failure from high-current loads and 3.3V
and 5V logic compatible enable inputs.
The MIC2537 is available in active-high and active-low ver-
sions in a 16-lead SOP package.
Features
•
•
•
•
•
•
•
•
•
•
•
•
Compliant to USB specifications
3V to 5.5V input
100mA minimum continuous load current per port
425mΩ typical on-resistance
< 400mA current limit
Individual open-drain fault flag leads
3V/5V-compatible enable inputs
Active-high (-1) and active-low (-2) versions
100µA max. on-state supply current
<1µA typical off-state supply current
16-lead SOP package
–40°C to 85°C operation
Applications
•
•
•
•
•
•
USB keyboards
USB bus-powered docking stations
Notebook docking stations
Notebook PCs
PDA
General power distribution
Typical Application
Upstream V
BUS
4.75V to 5.25V
500mA max.
10k
MIC5207-3.3
LDO Regulator
IN
4.7
µF
OUT
1µF
GND
3.3V USB Controller
V+
EN
OC
EN
OC
EN
D+
D–
Bold
lines indicate
0.1" wide, 1-oz. copper
high-current traces.
GND
OC
EN
OC
Ferrite
Bead
10k 10k 10k
MIC2537
ENA
FLGA
ENB
FLGB
ENC
FLGC
END
FLGD
IN
NC
OUTA
OUTB
OUTC
OUTD
NC
GND
V
BUS
33µF*
* 33µF, 16V tantalum or 100µF, 10V electrolytic per port
0.01µF
D+
D–
GND
Downstream
USB
Port 3
100mA max.
0.1
µF
33µF*
0.01µF
33µF*
0.01µF
V
BUS
D+
D–
GND
Downstream
USB
Port 1
100mA max.
V
BUS
D+
D–
GND
Downstream
USB
Port 2
100mA max.
V
BUS
33µF*
0.01µF
D+
D–
GND
Downstream
USB
Port 4
100mA max.
Typical Bus-Powered Hub
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
December 1999
1
MIC2537
MIC2537
Micrel
Ordering Information
Part Number
MIC2537-1BM
MIC2537-2BM
Enable
Active High
Active Low
Temperature Range
–40°C to +85°C
–40°C to +85°C
Package
16-Lead SOP
16-Lead SOP
Pin Configuration
MIC2537-x
FLGA
ENA
OUTA
GND
NC
OUTB
ENB
FLGB
1
2
3
4
5
6
7
8
16 FLGD
15 END
14 OUTD
13 IN
12 NC
11 OUTC
10 ENC
9
FLGC
16-Lead SOP (M)
Pin Description
Pin Number
1
2
3
4
5, 12
6
7
8
9
10
11
13
14
15
16
Pin Name
FLGA
ENA
OUTA
GND
NC
OUTB
ENB
FLGB
FLGC
ENC
OUTC
IN
OUTD
END
FLGD
Pin Function
Flag A: (Output): Channel A open-drain fault flag output.
Enable A (Input): Channel A control input.
Output A: Channel A switch output.
Ground: Supply return. Connect both leads to ground.
Not internally connected
Output B: Channel B switch output.
Enable B (Input): Channel B control input.
Flag B (Output): Channel B open-drain fault flag output.
Flag C (Output): Channel C open-drain fault flag output.
Enable C (Input): Channel C control input.
Output C: Channel C switch output.
Positive Supply Input
Output D: Channel D switch output.
Enable D (Input): Channel D control input.
Flag D (Output): Channel D open-drain fault flag output.
December 1999
2
MIC2537
MIC2537
Micrel
Absolute Maximum Ratings
(Note 1)
Supply Voltage (V
IN
) .....................................................+6V
Fault Flag Voltage (V
FLG
) .............................................. +6V
Fault Flag Current (I
FLG
) ............................................ 25mA
Output Voltage (V
OUT
) .................................................. +6V
Output Current (I
OUT
) ............................... Internally Limited
Control Input (V
EN
) ......................................... –0.3V to 12V
Storage Temperature (T
S
) ....................... –65°C to +150°C
Lead Temperature (Soldering 5 sec.) ....................... 260°C
ESD Rating, Note 3 ....................................................... 2kV
Operating Ratings
(Note 2)
Supply Voltage (V
IN
) ...................................... +3V to +5.5V
Ambient Operating Temperature (T
A
) ........ –40°C to +85°C
Thermal Resistance
SOP (θ
JA
) .......................................................... 120°C/W
Electrical Characteristics
V
IN
= +5V; T
A
= 25°C; unless noted.
Parameter
Supply Current
Condition
Note 4,
switch off, OUTA–D = open
Note 4,
all switches on, OUTA–D = open
Enable Input Threshold
low-to-high transition
high-to-low transition,
Note 4
Enable Input Current
V
EN
= V
OH(min)
= 2.4V
V
EN
= V
OL(max)
= 0.8V
Enable Input Capacitance
Switch Resistance
Output Turn-On Delay
Output Turn-On Rise Time
Output Turnoff Delay
Output Turnoff Fall Time
Output Leakage Current
Current Limit Threshold
Continuous Load Current
Short Circuit Current Limit
Overtemperature Shutdown
Threshold
Error Flag Output Resistance
single switch, 100mA load
R
L
= 50Ω, C
L
= 1µF,
Note 5
R
L
= 50Ω, C
L
= 1µF,
Note 5
R
L
= 50Ω, C
L
= 1µF,
Note 5
R
L
= 50Ω, C
L
= 1µF,
Note 5
each output (switch off)
ramped load applied to enable output,
Note 6
each output, FLG not active
each output (enabled into load), V
OUT
= 4.0V
T
J
increasing
T
J
decreasing
V
IN
= 5V, I
L
= 10mA
V
IN
= 3.3V, I
L
= 10mA
Error Flag Off Current
Note 1.
Note 2.
Note 3.
Note 4.
Note 5.
Note 6.
Min
Typ
0.75
70
1.8
Max
5
100
2.4
Units
µA
µA
V
V
µA
µA
pF
0.8
1.6
0.01
0.01
1
425
0.51
700
1
1
mΩ
ms
ms
µs
µs
µA
mA
mA
0.2
0.5
150
148
1
300
300
300
10
500
100
150
250
135
125
10
12
0.01
1
400
mA
°C
°C
Ω
Ω
µA
V
FLAG
= 5V
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, 1.5kΩ in series with 100pF.
Off is
≤
0.8V and on is
≥
2.4V for the MIC2537-1. Off is
≥
2.4V and on is
≤
0.8V for the MIC2537-2. The enable input has approximately
200mV of hysteresis. See control threshold charts.
See “Timing Diagrams.”
See “Functional Characteristics: Current-Limit Response” graph.
December 1999
3
MIC2537
MIC2537
Micrel
Typical Characteristics
Supply Current
vs. Supply Voltage
100
SUPPLY CURRENT (µA)
ON-RESISTANCE (mΩ)
Supply Current
vs. Temperature
V
IN
= 5V
100
SUPPLY CURRENT (µA)
80
60
40
500
400
300
200
Ouput On-Resistance
Variation vs. Supply Voltage
80
60
40
20
T
A
= 25°C
20
0
R
L
=
∞
V
IN
= 3.3V
R
L
=
∞
T
A
= 25°C
100
0
2
I
L
= 100mA
2
3
4
5
SUPPLY VOLTAGE (V)
6
0
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
3
4
5
SUPPLY VOLTAGE (V)
6
Output On-Resistance
Variation vs. Temperature
500
ON RESISTANCE (mΩ)
400
Overcurrent Threshold and
Current Limit vs. Supply Voltage
300
250
CURRENT (mA)
200
150
100
50
0
2
T
A
= 25°C
I
LIM
I
THR
CURRENT (mA)
300
250
200
150
100
Overcurrent Threshold and
Current Limit vs. Temperature
I
THR
300
200
100
V
IN
= 5V
I
L
= 100mA
I
LIM
50
0
-40 -20
V
IN
= 5V
0
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
3
4
5
SUPPLY VOLTAGE (V)
6
0
20
40
60
80 100
TEMPERATURE (°C)
Control Threshold
vs. Supply Voltage
2.0
THRESHOLD VOLTAGE (V)
2.0
Control Threshold
vs. Temperature
500
V
IH
400
V
IL
TIME (µs)
300
200
100
Output Rise Time
vs. Temperature
V
IH
ENABLE VOLTAGE (V)
1.5
V
IL
1.0
1.5
1.0
0.5
T
A
= 25°C
0.5
V
IN
= 5V
V
IN
= 5V
C
L
= 0.01µF
R
L
= 44Ω
0
2
3
4
5
SUPPLY VOLTAGE (V)
6
0
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
0
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
1.5
Output Fall Time
vs. Temperature
TIME (µs)
1.0
0.5
V
IN
= 5V
C
L
= 0.01µF
R
L
= 44Ω
0
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
December 1999
4
MIC2537
MIC2537
Micrel
Functional Characteristics
Input Voltage Response
(Input Voltage Rising: MIC2537-2)
V
OUT
V
FLG
V
I
N
I
OUT
(100mA/div.) (2V/div.) (2V/div.) (2V/div.)
Input Voltage Response
(Input Voltage Decreasing: MIC2537-2)
V
OUT
V
FLG
V
I
N
I
OUT
(100mA/div.) (2V/div.) (2V/div.) (2V/div.)
E
N
= 0V
R
L
= 24Ω
EN = 0V
R
L
= 24Ω
TIME (25ms/div.)
TIME (25ms/div.)
Current Limit Transient Response
(Heavy Load Applied to Output: MIC2537-2)
V
OUT
V
FLG
V
E
N
(5V/div.) (10V/div.)(5V/div.)
Current Limit Response
(Ramped Load: MIC2537-2)
V
OUT
V
FLG
V
E
N
(5V/div.) (10V/div.)(5V/div.)
1V
1V
250mA
Current Limit
Threshold
180mA
Short Circuit
Current Limit
V
IN
= 5V
V
IN
= 5V
I
OUT
(500mA/div.)
TIME (25µs/div.)
I
OUT
(100mA/div.)
TIME (5ms/div.)
December 1999
5
MIC2537
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