19-1865; Rev 0; 11/00
Dual USB Switch with Fault Blanking
General Description
The MAX1812 is a dual current-limited switch specifi-
cally made for USB applications. Each channel is guar-
anteed to supply 500mA and meets USB specifications.
The MAX1812’s low quiescent supply current (45µA)
and shutdown current (3µA) conserve battery power in
portable applications.
The MAX1812 has multiple safety features to ensure
that the USB port is protected. Built-in thermal-overload
protection limits power dissipation and junction temper-
ature. The device also has accurate internal current-lim-
iting circuitry to protect the input supply against both
overload and short-circuit conditions. Independent fault
signals (FAULTA and
FAULTB)
notify the microproces-
sor when a thermal-overload, current limit, undervoltage
lockout, or short-circuit fault occurs. A 20ms fault-blank-
ing feature enables the circuit to ignore momentary
faults, such as those caused when hot-swapping a
capacitive load, thereby preventing false alarms to the
host system.
The MAX1812 is available in a space-saving 10-pin
µMAX package. For single versions of this device, refer
to the MAX1693, MAX1694, and MAX1607 data sheets.
Features
o
Dual USB Switch in Tiny 10-Pin µMAX Package
o
Guaranteed 500mA Load per Channel
o
Built-In 20ms Fault Blanking
o
Compliant to USB Specifications
o
+4.0V to +5.5V Input Voltage Range
o
45µA Quiescent Current
o
3µA Shutdown Current
o
Independent Shutdown Control
o
Independent
FAULT
Indicator Outputs
o
Thermal-Overload Protection
o
UL Listing Pending
MAX1812
________________________Applications
USB Ports
USB Hubs
Notebook Computers
Desktop Computers
PDAs and Palmtop Computers
Docking Stations
PART
MAX1812EUB
Ordering Information
TEMP. RANGE
-40°C to +85°C
PIN-PACKAGE
10
µMAX
Typical Operating Circuit
INA
IN
OUTA
Pin Configuration
TOP VIEW
USB
PORT A
INPUT
4.0V TO 5.5V
INB
ONA
1
10
FAULTA
9
OUTA
GND
OUTB
FAULTB
MAX1812
FAULTA
FAULTB
ONA
ONB
ONA
ONB
OUTB
INA
USB
PORT B
2
3
4
5
IN
INB
ONB
MAX1812
8
7
6
GND
µMAX
________________________________________________________________
Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Dual USB Switch with Fault Blanking
MAX1812
ABSOLUTE MAXIMUM RATINGS
IN, INA, INB,
ONA, ONB,
OUTA, OUTB to GND......-0.3V to +6V
FAULTA, FAULTB
to GND .........................-0.3V to (V
IN
_ + 0.3V)
INA, IN to OUTA; INB, IN to OUTB..........................-0.3V to +6V
OUTA, OUTB Maximum Continuous Switch Current
(per channel, internally limited) .........................................1.2A
FAULTA, FAULTB
Current .................................................20mA
Continuous Power Dissipation (T
A
= +70°C)
10-Pin µMAX (derate 5.6mW/°C above +70°C) ............444mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
IN
= V
INA
= V
INB
= 5V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C) (Note 1)
PARAMETER
Supply Voltage Range
Switch On-Resistance
Standby Supply Current
Quiescent Supply Current
R
ON
T
A
= +25°C, each switch
T
A
= -40°C to +85°C, each switch
Both switches disabled
Both switches enabled, I
OUTA
= I
OUTB
= 0
Switches disabled, V
OUTA
= V
OUTB
= 0,
T
A
= +25°C
Switches disabled, V
OUTA
= V
OUTB
= 0,
T
A
= -40°C to 85°C
Undervoltage Lockout Threshold
Continuous Load Current
Continuous Current Limit
Short-Circuit Current Limit
Short-Circuit Detect Threshold
Continuous Current-Limit
Blanking Timeout Period
Short-Circuit Blanking Timeout
Period
Turn-On Delay
Output Rise Time
Turn-Off Delay from ON
Output Fall Time
Thermal Shutdown Threshold
ILIM
ISHORT
V
IN
_ - V
OUT
_ = 0.5V
V
OUT
_ = 0 (I
OUT
pulsing)
(Note 2)
From continuous current-limit condition to
FAULT_
assertion
From short-circuit current-limit condition to
FAULT_
assertion
R
OUT
= 10Ω, C
OUT
= 1µF does not include
rise time (from
ON_
to 10% of V
OUT
)
R
OUT
= 10Ω, C
OUT
= 1µF, from 10% to
90% of V
OUT
R
OUT
= 10Ω, C
OUT
= 1µF does not include
fall time (from
ON_
to 90% of V
OUT
)
C
OUT
= 1µF, R
OUT
= 10Ω, from 90% to 10%
of V
OUT
15°C hysteresis
10
7.5
0.5
UVLO
Rising edge, 3% hysteresis
3.0
500
0.6
0.8
0.9
1.2
0.35
1
20
18
1.2
2.5
0.8
2.5
160
3
35
35
4.0
1.2
1.6
3.4
3
45
0.002
SYMBOL
CONDITIONS
MIN
4.0
75
TYP
MAX
5.5
105
135
10
100
1
µA
10
3.8
V
mA
A
A(peak)
A
RMS
V
ms
ms
ms
ms
ms
ms
°C
UNITS
V
mΩ
µA
µA
OUT_ Leakage Current
2
_______________________________________________________________________________________
Dual USB Switch with Fault Blanking
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
INA
= V
INB
= 5V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
FAULT_
Output Low Voltage
FAULT_
Output High Leakage
Current
SYMBOL
CONDITIONS
V
IN_
= +4V to +5.5V
V
IN_
= +4V to +5.5V
V
ON_
= 0 or V
IN_
I
SINK
= 1mA, V
IN_
= 4V
V
IN_
= V
FAULT_
= 5.5V
-1
MIN
2
0.8
1
0.4
1
TYP
MAX
UNITS
V
V
µA
V
µA
MAX1812
Note 1:
Specifications to -40°C are guaranteed by design, not production tested.
Note 2:
The output voltage at which the device transitions from short-circuit current limit to continuous current limit.
Typical Operating Characteristics
(V
IN
= V
INA
= V
INB
= 5V, Circuit of Figure 2, T
A
= +25°C, unless otherwise noted.)
QUIESCENT CURRENT
vs. INPUT VOLTAGE
MAX1812 toc01
QUIESCENT CURRENT
vs. TEMPERATURE
MAX1812 toc02
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
V
ONA
= V
ONB
= V
IN
4
MAX1812 toc03
100
V
ONA
= V
ONB
= 0V
QUIESCENT CURRENT (µA)
75
55
V
IN
= 5.5V
50
V
IN
= 5V
5
SHUTDOWN SUPPLY CURRENT (µA)
QUIESCENT CURRENT (µA)
3
50
2
45
V
IN
= 4.5V
25
1
0
0
1
2
3
4
5
6
INPUT VOLTAGE (V)
40
-40
-15
10
35
60
85
TEMPERATURE (°C)
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
_______________________________________________________________________________________
3
Dual USB Switch with Fault Blanking
MAX1812
Typical Operating Characteristics
(V
IN
= V
INA
= V
INB
= 5V, Circuit of Figure 2, T
A
= +25°C, unless otherwise noted.)
OUT_ LEAKAGE CURRENT
vs. TEMPERATURE
MAX1812 toc04
NORMALIZED R
ON
vs. TEMPERATURE
MAX 1812 toc05
CONTINUOUS CURRENT LIMIT
vs. TEMPERATURE
890
CONTINUOUS CURRENT LIMIT (mA)
880
870
860
850
840
830
820
810
V
IN
= 5V
MAX1812 toc06
1000
V
ONA
= V
ONB
= V
IN
LEAKAGE CURRENT (nA)
100
1.50
V
ONA
= V
ONB
= 0V
1.25
NORMALIZED R
ON
900
10
1.00
0.75
1
0.1
-40
-15
10
35
60
85
TEMPERATURE (°C)
0.50
-40
-15
10
35
60
85
TEMPERATURE (°C)
800
-40
-15
10
35
60
85
TEMPERATURE (°C)
TOTAL TURN-ON TIME
vs. TEMPERATURE
MAX1812 toc07
TOTAL TURN-OFF TIME
vs. TEMPERATURE
MAX1812 toc08
FAULT-BLANKING TIME
vs. TEMPERATURE
V
IN
= 5.0V
FAULT-BLANKING TIME (ms)
21.5
MAX1812 toc09
4.0
3.9
TOTAL TURN-ON TIME (ms)
3.8
3.7
3.6
3.5
3.4
3.3
3.2
3.1
3.0
-40
-15
10
35
60
TOTAL TURN-ON
TIME = RISE TIME + DELAY TIME
V
IN
= 5.5V
V
IN
= 5V
V
IN
= 4.5V
3.6
3.5
TOTAL TURN-OFF TIME (ms)
3.4
3.3
3.2
3.1
3.0
2.9
2.8
2.7
2.6
TOTAL TURN-OFF
TIME = FALL TIME + DELAY TIME
V
IN
= 4.5V
V
IN
= 5V
V
IN
= 5.5V
22.0
21.0
20.5
20.0
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
85
TEMPERATURE (°C)
FAULT OUTPUT LOW VOLTAGE
vs. TEMPERATURE
MAX1812 toc10
OVERLOAD RESPONSE INTO 2.5Ω LOAD
MAX1812-11
OVERLOAD RESPONSE INTO 2.5Ω LOAD
(EXPANDED TIME SCALE)
MAX1812-12
0.250
FAULT OUTPUT LOW VOLTAGE (V)
0.225
0.200
V
IN
= 4.5V
0.175
0.150
0.125
0.100
-40
-15
10
35
60
V
IN
= 5V
A
5V
A
5V
B
FAULT RECOVERS
C
0
B
C
0
0
V
IN
= 5.5V
D
0
5ms/div
C : V
FAULTA,
5V/div
D : I
OUTA,
1A/div
D
LOAD REMOVED
0
0
85
A : V
IN,
5V/div
B : V
OUTA,
5V/div
TEMPERATURE (°C)
A : V
IN,
5V/div
B : V
OUTA,
5V/div
500µs/div
C : V
FAULTA,
5V/div
D : I
OUTA,
1A/div
4
_______________________________________________________________________________________
Dual USB Switch with Fault Blanking
MAX1812
Typical Operating Characteristics (continued)
(V
IN
= V
INA
= V
INB
= 5V, Circuit of Figure 2, T
A
= +25°C, unless otherwise noted.)
SHORT-CIRCUIT RESPONSE INTO 0Ω
MAX1812-13
SHORT-CIRCUIT RESPONSE INTO 0Ω LOAD
(EXPANDED TIME SCALE)
5V
A
B
0
C
0
MAX1812-14
SWITCH TURN-ON TIME
5V
A
MAX1812-15
A
B
0
C
0
FAULT RECOVERS
0
B
LOAD REMOVED
D
A : V
IN,
1V
B : V
OUTA,
5V/div
10ms/div
C : V
F AULTA,
5V/div
D : I
OUTA,
1A/div
0
D
A : V
IN,
1V/div
B : V
OUTA,
5V/div
400µs/div
C : V
FAULTA,
5V/div
D : I
OUTA,
1A/div
0
1ms/div
A : V
ONA,
5V/div
B : V
OUTA,
1V/div
R
L
= 10Ω
C
OUT
= 1µF
0
SWITCH TURN-OFF TIME
MAX1812-16
STARTUP TIME
(TYPICAL USB APPLICATION)
MAX1812-17
A
R
L
= 10Ω
C
OUT
= 1µF
0
A
B
0
0
B
R
L
= 10Ω
C
OUT
= 150µF
0
1ms/div
A : V
ONA,
5V/div
B : V
OUTA,
1V/div
C
500µs/div
C : V
OUTA,
2V/div
D : I
OUTA,
0.5A/div
0
0
A : V
ONA,
5V/div
B : V
FAULTA,
5V/div
_______________________________________________________________________________________
5
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