June 1999
1
MIC2524/2527
MIC2524/2527
Micrel
MIC2524/2527
Quad USB Power Control Switch
Not Recommended for New Designs
Refer to MIC2027
General Description
The MIC2524 and MIC2527 are cost-effective high-side
power switches with four independently controlled channels,
optimized for self-powered and bus-powered Universal Se-
rial Bus (USB) applications. Few external components are
necessary to satisfy USB requirements.
The MIC2524/7 satisfies the following USB requirements:
each switch channel supplies up to 500mA as required by
USB downstream devices; the switch's low on-resistance
meets USB voltage drop requirements; fault current is limited
to typically 750mA, 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,
undervoltage lockout (UVLO) to ensure that the device re-
mains off unless there is a valid input voltage present, and
3.3V and 5V logic compatible enable inputs.
The MIC2524/7 is available in active-high and active-low
versions in 16-pin DIP and SOIC packages.
Typical Application
ON/OFF
OVERCURRENT
MIC2524
MIC2527
3.3V USB Controller
V
BUS
D+
D
GND
V
BUS
D+
D
GND
27k
MIC5207-3.3
LDO Regulator
IN
OUT
GND
33F*
Ferrite
Bead
D+
D
V+
ENA
IN
FLGA
IN
ENB
OUTA
FLGB
OUTB
Bold lines indicate
0.1" wide, 1-oz. copper
high-current traces.
Downstream
USB
Port 1
500mA max.
Downstream
USB
Port 2
500mA max.
33F*
0.1
F
V
BUS
D+
D
GND
V
BUS
D+
D
GND
33F*
ENC
OUTD
FLGC
END
GND
FLGD
GND
Downstream
USB
Port 3
500mA max.
Downstream
USB
Port 4
500mA max.
33F*
0.01F
0.01F
0.01F
0.01F
4.7
F
1F
GND
MIC2527
5.1V
3%
5V
1%
or
MIC2524
5V
3%
* 33F, 16V tantalum or 100F, 10V electrolytic per port
OUTC
10k
4-Port Self-Powered Hub
Features
Compliant to USB specifications
UL Recognized Component
4 independent switches
3V to 5.5V input
500mA minimum continuous load current per port
140m
maximum on-resistance (MIC2524)
1.25A maximum short circuit current limit
Individual open-drain fault flag pins
220
A on-state supply current
1
A typical off-state supply current
Output can be forced higher than input (off-state)
Thermal shutdown
2.4V typical undervoltage lockout (UVLO)
1ms turn-on (soft-start) and fast turnoff
Active-high or active-low enable versions
16-pin SOIC and DIP packages
Applications
USB bus-powered hubs
USB self-powered hubs
USB monitors
USB printers
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
MIC2524/2527
Micrel
MIC2524/2527
2
June 1999
Pin Description
Pin Number
Pin Name
Pin Function
1
FLGA
Flag A: (Output): Channel A open-drain fault flag output.
2
ENA
Enable A (Input): Channel A control input.
3
OUTA
Output A: Channel A switch output.
4, 12
GND
Ground: Supply return. Connect both pins to ground.
5
IN(C/D)
Supply Input: Channel C and D switch, logic, and charge-pump supply input.
6
OUTC
Output C: Channel C switch output.
7
ENC
Enable C (Input): Channel C control input.
8
FLGC
Flag C (Output): Channel C open-drain fault flag output.
9
FLGD
Flag D (Output): Channel D open-drain fault flag output.
10
END
Enable D (Input): Channel D control input.
11
OUTD
Output D: Channel D switch output.
13
IN(A/B)
Supply Input: Channel A and B switch, logic, and charge-pump supply input.
14
OUTB
Output B: Channel B switch output.
15
ENB
Enable B (Input): Channel B control input.
16
FLGB
Flag B (Output): Channel B open-drain fault flag output.
Pin Configuration
1
2
3
4
16
15
14
13
FLGB
ENB
OUTB
IN(A/B)
FLGA
ENA
OUTA
GND
5
6
7
8
12
11
10
9
GND
OUTD
END
FLGD
IN(C/D)
OUTC
ENC
FLGC
16-Pin SOIC (WM)
16-Pin DIP (N)
Ordering Information
Part Number
On-Resistance
Enable
Temperature Range
Package
MIC2524-1BWM
100m
typ.
Active High
40
C to +85
C
16-Pin SOIC
MIC2524-1BN
100m
typ.
Active High
40
C to +85
C
16-pin DIP
MIC2524-2BWM
100m
typ.
Active Low
40
C to +85
C
16-Pin SOIC
MIC2524-2BN
100m
typ.
Active Low
40
C to +85
C
16-pin DIP
MIC2527-1BWM
200m
typ.
Active High
40
C to +85
C
16-Pin SOIC
MIC2527-1BN
200m
typ.
Active High
40
C to +85
C
16-pin DIP
MIC2527-2BWM
200m
typ.
Active Low
40
C to +85
C
16-Pin SOIC
MIC2527-2BN
200m
typ.
Active Low
40
C to +85
C
16-pin DIP
LOGIC,
CHARGE
PUMP
LOGIC,
CHARGE
PUMP
3 OUTA
14 OUTB
13 IN(A/B)
ENA 2
FLGA 1
ENB 15
FLGB 16
LOGIC,
CHARGE
PUMP
LOGIC,
CHARGE
PUMP
6 OUTC
11 OUTD
5 IN(C/D)
ENC 7
FLGC 8
END 10
FLGD 9
12
4 GND
Functional Pinout
June 1999
3
MIC2524/2527
MIC2524/2527
Micrel
Electrical Characteristics
V
IN
= +5V; T
A
= 25
C; unless noted.
Parameter
Condition
Min
Typ
Max
Units
Supply Current
Note 4, switch off, OUT = open
1.5
10
A
Note 4, all switches on, OUT = open
220
320
A
Enable Input Threshold
low-to-high transition
2.1
2.4
V
high-to-low transition, Note 4
0.8
1.9
V
Enable Input Current
V
EN
= 0V to 5.5V
1
0.01
1
A
Enable Input Capacitance
1
pF
Switch Resistance
MIC2524, I
OUT
= 500mA, each switch
100
140
m
MIC2527, I
OUT
= 500mA, each switch
200
300
m
Output Turn-On Delay
R
L
= 10
each output
0.5
ms
Output Turn-On Rise Time
R
L
= 10
each output
1
ms
Output Turnoff Delay
R
L
= 10
each output
1
20
s
Output Turnoff Fall Time
R
L
= 10
each output
1
20
s
Output Leakage Current
each output (output disabled)
10
A
Continuous Load Current
each output
0.5
A
Short-Circuit Current Limit
each output (enable into load), V
OUT
= 4.0V
0.5
0.75
1.25
A
Current-Limit Threshold
ramped load applied to enabled output, V
OUT
4.0V, Note 5
1.6
2.2
A
Overtemperature Shutdown
T
J
increasing
135
C
Threshold
T
J
decreasing
125
C
Error Flag Output Resistance
V
IN
= 5V, I
L
= 10mA
10
V
IN
= 3.3V, I
L
= 10mA
15
Error Flag Off Current
V
FLAG
= 5V
0.01
1
A
UVLO Threshold
V
IN
= increasing
2.5
V
V
IN
= decreasing
2.3
V
Note 1.
Exceeding the absolute maximum rating may damage the device.
Note 2.
The device is not guaranteed to function outside its operating rating.
Note 3.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
Note 4.
Off is
0.8V and on is
2.4V for the MIC252x-1. Off is
2.4V and on is
0.8V for the MIC252x-2. The enable input has approximately 200mV
of hysteresis. See control threshold charts.
Note 5.
See "Functional Characteristics: Current-Limit Response" photo.
Absolute Maximum Ratings
(Note 1)
Supply Voltage (V
IN
) ..................................................... +6V
Fault Flag Voltage (V
FLG
) .............................................. +6V
Fault Flag Current (I
FLG
) ............................................ 50mA
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
SOIC (
JA
) ......................................................... 120
C/W
DIP(
JA
) ............................................................. 130
C/W
MIC2524/2527
Micrel
MIC2524/2527
4
June 1999
Typical Characteristics
V
IN
= 5V; T
A
= 25
C; one switch section; unless noted.
80
90
100
110
3.0
3.5
4.0
4.5
5
5.5
OUTPUT RESISTANCE (m
)
SUPPLY VOLTAGE (V)
Output On-Resistance
vs. Supply Voltage
T = 25
C
R
L
= 44
Awaiting Full
Characterization
Data
60
80
100
120
140
-40 -20
0
20
40
60
80 100
ON-RESISTANCE (m
)
TEMPERATURE (
C)
Output On-Resistance
vs. Temperature
R
L
= 44
V
IN
= 5V
1.5
2.0
2.5
3.0
-40 -20
0
20
40
60
80 100
THRESHOLD VOLTAGE (V)
TEMPERATURE (
C)
UVLO Threshold Voltage
vs. Temperature
RISING
FALLING
0
100
200
300
400
500
0
2
4
6
8
SUPPLY CURRENT (
A)
SUPPLY VOLTAGE (V)
On-State Supply Current
vs. Supply Voltage
ALL SWITCHES ON
0
0.5
1.0
1.5
2.0
2
3
4
5
6
7
8
SUPPLY CURRENT (
A)
SUPPLY VOLTAGE (V)
Off-State Supply Current
vs. Supply Voltage
ALL SWITCHES OFF
1.0
1.5
2.0
2.5
2
3
4
5
THRESHOLD VOLTAGE (V)
SUPPLY VOLTAGE (V)
Control Threshold
vs. Supply Voltage
V
CTL
RISING
V
CTL
FALLING
0
50
100
150
200
250
300
350
400
-40 -20
0
20
40
60
80 100
SUPPLY CURRENT (
A)
TEMPERATURE (
C)
On-State Supply Current
vs. Temperature
ALL SWITCHES ON
0
0.5
1.0
1.5
2.0
-40 -20
0
20
40
60
80 100
SUPPLY CURRENT (
A)
TEMPERATURE (
C)
Off-State Supply Current
vs. Temperature
ALL SWITCHES OFF
1.0
1.5
2.0
2.5
-40 -20
0
20
40
60
80 100
ENABLE VOLTAGE (V)
TEMPERATURE (
C)
Control Threshold
vs. Temperature
V
EN
RISING
V
IN
= 5V
V
EN
FALLING
0
1
2
3
4
5
-40 -20
0
20
40
60
80 100
TIME (
s)
TEMPERATURE (
C)
Output Rise Time
vs. Temperature
Awaiting Full
Characterization
Data
0
0.2
0.4
0.6
0.8
1.0
-40 -20
0
20
40
60
80 100
TIME (ms)
TEMPERATURE (
C)
Output Fall Time
vs. Temperature
Awaiting Full
Characterization
Data
1.0
1.2
1.4
1.6
1.8
2.0
-25
0
25
50
75
100
CURRENT (A)
TEMPERATURE (
C)
Current-Limit Threshold
vs. Temperature
SHORT CIRCUIT
CURRENT LIMIT
CURRENT LIMIT
THRESHOLD
June 1999
5
MIC2524/2527
MIC2524/2527
Micrel
Turn-On, Turnoff
Characteristics
R
L
= 35
V
IN
= 5.0V
144mA
TIME (2.5ms/div.)
I
OUT
(100mA/div
.
)
V
EN
(5V/div
.
)
V
FLG
(5V/div
.
)
V
OUT
(2V/div
.
)
C
L
= 10
F
Turn-On, Turnoff
Characteristics
R
L
= 35
C
L
= 150
F
TIME (2.5ms/div.)
I
OUT
(100mA/div
.
)
V
EN
(5V/div
.
)
V
FLG
(5V/div
.
)
V
OUT
(2V/div
.
)
144mA
Functional Characteristics
Short Circuit Response
(Short Applied to Output)
TIME (500ms/div.)
I
OUT
(1A/div
.
)
V
OUT
(2V/div
.
)
V
FLG
(5V/div
.
)
Thermal Shutdown
1A Short Circuit Current Limit
Short Circuit Response
Enable into Short Circuit
1.1A Short Circuit
Current-Limiting
TIME (250ms/div.)
I
OUT
(1A/div
.
)
V
EN
(5V/div
.
)
V
FLG
(5V/div
.
)
V
OUT
(2V/div
.
)
Thermal
Shutdown
Input Voltage
Response
2.6V (UVLO) Threshold
TIME (100ns/div.)
I
OUT
(200mA/div
.
)
V
EN
(2V/div
.
)
V
FLG
(5V/div
.
)
V
OUT
(2V/div
.
)
R
L
= 35
V
IN
= 5.0V
C
L
= 15
F
MIC2524/2527
Micrel
MIC2524/2527
6
June 1999
Short Circuit Transient Response
(Short Applied to Output)
1A Current Limit
TIME (500
s/div.)
I
OUT
(1A/div
.
)
V
OUT
(5V/div
.
)
V
FLG
(5V/div
.
)
2.76A
Current-Limit Response
(Ramped Load)
TIME (1ms/div.)
I
OUT
(1A/div
.
)
V
FLG
(5V/div
.
)
V
OUT
(2V/div
.
)
Current Limit
Threshold
1A Current
Limit
Test Circuit
MIC2524/7
Ferrite
Bead
ENA
IN
FLGA
NC
ENB
OUTA
FLGB
OUTB
I
LOAD
(for Current
Limit Response)
C
L
ENC
OUTD
FLGC
END
NC
FLGD
GND
R
L
OUTC
5V
10k
(1 output shown)
I
OUT
0.1F
Functional Characteristics Test Circuit
June 1999
7
MIC2524/2527
MIC2524/2527
Micrel
Block Diagrams
1.2V
REFERENCE
THERMAL
SHUTDOWN
CHARGE
PUMP
OUTB
UVLO
GATE
CONTROL
IN (A/B)
ENA
GATE
CONTROL
OUTA
FLGB
CHARGE
PUMP
ENB
OSC.
FLGA
CURRENT
LIMIT
CURRENT
LIMIT
1.2V
REFERENCE
THERMAL
SHUTDOWN
CHARGE
PUMP
OUTD
UVLO
GATE
CONTROL
IN (C/D)
ENC
GATE
CONTROL
OUTC
FLGD
CHARGE
PUMP
END
OSC.
FLGC
CURRENT
LIMIT
CURRENT
LIMIT
GND
MIC2527
MIC2524/2527
Micrel
MIC2524/2527
8
June 1999
Functional Description
The MIC2524/7-1 and MIC2524/7-2 are quad high-side
switches with active-high and active-low enable inputs, re-
spectively. Fault conditions turn off or inhibit turn-on of one or
more of the output transistors, depending upon the type of
fault, and activate the open-drain error flag transistors mak-
ing them sink current to ground.
Input and Output
IN (input) is the power supply connection to the logic circuitry
and the drain of the output MOSFET. OUTx (output) is the
source of its respective MOSFET. In a typical circuit, current
flows through the switch from IN to OUT toward the load. If
V
OUT
is greater than V
IN
, current will flow from OUT to IN
since the MOSFET is bidirectional when on.
The output MOSFET and driver circuitry are also designed to
allow the MOSFET source to be externally forced to a higher
voltage than the drain (V
OUT
> V
IN
) when the output is off. In
this situation, the MIC2524/7 prevents reverse current flow.
If V
IN
< 2.5V, UVLO disables both switches.
Thermal Shutdown
Thermal shutdown shuts off the affected output MOSFETs
and signals all fault flags if the die temperature exceeds
135
C. 10
C of hysteresis prevents the switch from turning on
until the die temperature drops to 125
C. Overtemperature
detection functions only when at least one switch is enabled.
Current Limit Induced Thermal Shutdown
Internal circuitry increases the output MOSFET on-resis-
tance until the series combination of the MOSFET on-resis-
tance and the load impedance limit current to typically 850mA.
The increase in power dissipation, in most cases, will cause
the MIC2524/7 to go into thermal shutdown, disabling af-
fected channels. When this is undesirable, thermal shutdown
can be avoided by externally responding to the fault and
disabling the current limited channel before the shutdown
temperature is reached. The delay between the flag indica-
tion of a current limit fault and thermal shutdown will vary with
ambient temperature, board layout, and load impedance, but
is typically several hundred milliseconds. The USB controller
must therefore recognize a fault and disable the appropriate
channel within this time. If the fault is not removed or the
switch is not disabled within this time, then the device will
enter into a thermal oscillation of about 2Hz. This does not
cause any damage to the device. Refer to "Functional Char-
acteristics: Thermal Shutdown Response."
Undervoltage Lockout
UVLO (undervoltage lockout) prevents the output MOSFET
from turning on until V
IN
exceeds approximately 2.5V. In the
undervoltage state, the FLAG will be low. After the switch
turns on, if the voltage drops below approximately 2.3V,
UVLO shuts off the output MOSFET and signals fault flag.
Undervoltage detection functions only when at least one
switch is enabled.
Current Sensing and Limiting
The current-limit threshold is preset internally. The preset
level prevents damage to the output MOSFET and external
load but allows a minimum current of 0.5A through the output
MOSFET of each channel.
The current-limit circuit senses a portion of the output FET
switch current. The current sense resistor shown in the block
diagram is virtual and has no voltage drop. The reaction to an
overcurrent condition varies with three scenarios:
Switch Enabled into Short Circuit
If a switch is powered on or enabled into a heavy load or short-
circuit, the switch immediately goes into a constant-current
mode, reducing the output voltage. The fault flag goes low
until the load is reduced. See the "Functional Characteristics:
Short Circuit Response, Enabled into Short Circuit" photo.
Short Circuit Applied to Output
When a heavy load is applied, a large transient current may
flow until the current limit circuitry will respond. Once this
occurs, the device limits current to less than the short-circuit
current limit specification. See the "Short Circuit Transient
Response, Short Applied to Output" graph.
Current-Limit Response
The MIC2524/7 current-limit profile exhibits a small foldback
effect of approximately 500mA. Once this current-limit thresh-
old is exceeded the device enters constant-current mode.
This constant current is specified as the short circuit current
limit in the "Electrical Characteristics" table. It is important to
note that the MIC2524/7 will deliver load current up to the
current-limit threshold which is typically 1.6A. Refer to "Func-
tional Characteristics: Current-Limit Response" photo for
details.
Fault Flag
FLG is an N-channel, open-drain MOSFET output. The fault-
flag is active (low) for one or more of the following conditions:
undervoltage (while 2V < V
IN
< 2.7), current limit, or thermal
shutdown. The flag output MOSFET is capable of sinking a
10mA load to typically 100mV above ground. Multiple FLG
pins may be "wire NORed" to a common pull-up resistor.
June 1999
9
MIC2524/2527
MIC2524/2527
Micrel
Applications Information
Supply Filtering
A 0.1
F to 1
F bypass capacitor from IN to GND, located at
the device, is strongly recommended to control supply tran-
sients. Without a bypass capacitor, an output short may
cause sufficient ringing on the input (from supply lead induc-
tance) to damage internal control circuitry.
Input or output transients must not exceed the absolute
maximum supply voltage (V
IN max
= 7V) even for a short
duration.
MIC2524/7
FLGA
FLGB
ENA
OUTA OUTB
GND
IN
ENB
0.1F to 1F
V
IN
2.7V to 5.5V
IN
GND
OUTC
ENC
END
FLGC
FLGD
OUTD
0.1F to 1F
Figure 1. Supply Bypassing
Enable Input
EN must be driven logic high or logic low for a clearly defined
input. Floating the input may cause unpredictable operation.
EN should not be allowed to go negative with respect to GND.
Soft Start
The MIC2524/7 presents a high impedance when off, and
slowly becomes a low impedance as it turns on. This reduces
inrush current and related voltage drop that results from
charging a capacitive load, satisfying the USB voltage droop
requirements.
Transient Overcurrent Filter
When the MIC2524/7 is enabled, large values of capacitance
at the output of the device will cause inrush current to exceed
the short circuit current-limit threshold of the device and
assert the flag. The duration of this time will depend on the
size of the output capacitance. Refer to the "Functional
Characteristics" turn-on and turnoff behaviors for details.
During the capacitance charging time, the device enters into
constant-current mode. As the capacitance is charged, the
current decreases below the short circuit current-limit thresh-
old, and the flag will then be deasserted.
In USB applications, it is required that output bulk capaci-
tance is utilized to support hot-plug events. When the
MIC2524/7 is enabled, the flag may go active for about 1ms
due to inrush current exceeding the current-limit setpoint.
Additionally, during hot-plug events, inrush currents may also
cause the flag to go active for 30
s. Since these conditions
are not valid overcurrent faults, the USB controller must
ignore the flag during these events. To prevent this erroneous
overcurrent reporting, a 1ms RC filter as shown in Figure 2
may be used. Alternatively, a 1ms debounce routine may be
programmed into the USB logic controller, eliminating the
need for the RC filter.
FLGA
FLGB
FLGC
FLGD
10k
10k
0.1F
OVERCURRENT
USB Controller
Figure 2. Transient Filter
MIC2524/2527
Micrel
MIC2524/2527
10
June 1999
Package Information
45
0
8
0.244 (6.20)
0.228 (5.79)
0.394 (10.00)
0.386 (9.80)
SEATING
PLANE
0.020 (0.51)
REF
0.020 (0.51)
0.013 (0.33)
0.157 (3.99)
0.150 (3.81)
0.050 (1.27)
0.016 (0.40)
0.0648 (1.646)
0.0434 (1.102)
0.050 (1.27)
BSC
PIN 1
DIMENSIONS:
INCHES (MM)
0.0098 (0.249)
0.0040 (0.102)
16-Pin SOP (M)
0.020
(0.508)
0.018
0.003
(0.457
0.076)
PIN 1
0.780
(19.812)
.250
0.005
(6.350
0.127)
0.025
0.015
(0.635
0.381)
0.100
0.010
(2.540
0.254)
MAX
0.030-0.110
(0.762-2.794)
RAD
0.125
(3.175)
MIN
0.020
(0.508)
MIN
0.130
0.005
(3.302
0.127)
+0.025
0.015
+0.635
0.381
0.325
8.255
(
)
0.009-0.015
(0.229-0.381)
0
-10
0.290-0.320
(7.336-8.128)
0.040
(1.016)
TYP
16-Pin Plastic DIP (N)
June 1999
11
MIC2524/2527
MIC2524/2527
Micrel
MIC2524/2527
Micrel
MIC2524/2527
12
June 1999
MICREL INC.
1849 FORTUNE DRIVE
SAN JOSE, CA 95131
USA
TEL
+ 1 (408) 944-0800
FAX
+ 1 (408) 944-0970
WEB
http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or
other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.
1999 Micrel Incorporated
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