UNISONIC TECHNOLOGIES CO., LTD
US3X77
POWER DISTRIBUTION SWITCH
DESCRIPTION
The UTC
US3X77
is a power distribution switch and particularly
designed for self-powered and bus-powered Universal Serial Bus
(USB) applications.
The UTC
US3X77
incorporates protection circuits including
current limiting circuit with foldback function, thermal shutdown circuit
designed to prevent catastrophic switch failure due to increasing
power dissipation when continuous heavy loads or short circuit
occurs. Besides, a built-in charge pump is used to drive the
N-channel MOSFET that is free of parasitic body diode to eliminate
any reversed current flow across the switch when it is powered off.
The R
DS(ON)
of the MOSFET switch is as low as 100mΩ. OC is
open-drain output report over-current or over-temperature event
which has deglitch typical 9ms timeout period typically 9ms.
The UTC
US3X77
is applied in high-side power protection
switch, USB power management, USB host and self-powered bubs,
USB bus-powered hubs, hot plug-in power supplies, battery-charger
circuits.
CMOS IC
FEATURES
* 100mΩ High-Side MOSFET
* Supply Current:
Switch on : 65μA(Typ)
Switch off : 1μA (Max)
* Accurate Current Limit with Foldback
* Deglitched Open-Drain Over-Current Flag Output (OC)
* No Reverse Current when Power Off
* Under voltage Lockout
* Operating Range:2.7V ~ 5.5V
* Output Shutdown Pull-low Resistor
ORDERING INFORMATION
Ordering Number
Lead Free
US3X77XL-S08-R
US3X77XL-S08-T
US3X77XL-SM1-R
US3X77XL-SM1-T
Halogen Free
US3X77XG-S08-R
US3X77XG-S08-T
US3X77XG-SM1-R
US3X77XG-SM1-T
Package
SOP-8
SOP-8
MSOP-8
MSOP-8
Packing
Tape Reel
Tube
Tape Reel
Tube
www.unisonic.com.tw
Copyright © 2011 Unisonic Technologies Co., Ltd
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QW-R502-568.B
US3X77
PIN CONFIGURATION
GND
1
8
7
6
5
OUT
OUT
NC
OC
CMOS IC
IN 2
IN 3
EN(EN) 4
PIN DESCRIPTION
PIN NO.
1
2, 3
4
5
6
7, 8
PIN NAME
GND
IN
EN(EN)
OC
NC
OUT
DESCRIPTION
Ground
Input Supply: Output MOSFET Drain, which also supplies IC's internal circuitry.
Connect to positive supply.
Enable: Logic level enable input. Make sure EN pin never floating.
Over-Current: Open-Drain OC output.
No connection.
Switch Output: Output MOSFET Source of switch. Typically connect to switched side of
load.
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QW-R502-568.B
US3X77
BLOCK DIAGRAM
CMOS IC
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QW-R502-568.B
US3X77
ABSOLUTE MAXIMUM RATING
(T
A
= 25°C, unless otherwise specified)
PARAMETER
SYMBOL
V
IN
V
OUT
V
EN
I
OUT
T
STG
CMOS IC
RATINGS
UNIT
Supply Voltage
6
V
Output Voltage
6
V
Enable Input
-0.3 ~ 6
V
Output Current
Internally Limited
A
Storage Temperature
-65~ +150
℃
Reflow Temperature (Soldering, 10sec)
260
℃
ESD Protection
2
kV
Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
OPERATING RATINGS
PARAMETER
Supply Voltage
Operating Temperature
SYMBOL
V
IN
T
A
RATINGS
+3 ~ +5.5
-40 ~ +85
UNIT
V
°C
ELECTRICAL CHARACTERISTICS
(V
IN
= 5V, C
IN
=1µF, C
OUT
=1µF, R
L
=10Ω, T
A
= 25°C, unless otherwise specified)
PARAMETER
SYMBOL
TEST CONDITIONS
Input Voltage
V
IN
US3477, I
OUT
=1.5A
US3377, I
OUT
=1.0A
Output MOS R
DS(ON)
US3277, I
OUT
=0.5A
US3177, I
OUT
=0.3A
Supply Current
I
IN
Output Turn-on Rising Time
R
L
=10Ω, 90% Settling
US3477
US3377
Current Limit Threshold
I
THD(LIMIT)
V
OUT
=4V
US3277
US3177
US3477
V
OUT
=0V,
US3377
Short-Circuit Current
I
SC
2.7V<V
IN
<5.5V
US3277
US3177
EN Input Threshold
Shutdown Supply Current
Shutdown Pull Low Resistance
Output Leakage Current
V
IN
Under Voltage Lockout
V
IN
Under Voltage Hysteresis
Thermal Limit
Thermal Limit Hysteresis
OC Deglitch
OC Output Low Voltage
OC Off-State Current
I
SHDN
I
O(LEAK)
EN=”0”, V
OUT
=0V
2.2
MIN
2.7
TYP
MAX UNIT
5.5
V
115
mΩ
µA
µs
3.3
2.6
1.9
1.45
2.3
1.7
1.3
0.9
1.8
1
150
1
2.7
A
100
65
400
2.5
2
1.5
1
1.7
1.3
1
0.7
1.6
0.1
75
0.5
2.5
200
135
20
9
2
1.6
1.2
0.75
0.2
0.2
0.2
0.2
1
A
V
µA
Ω
µA
V
mV
℃
℃
ms
V
µA
OC assertion or deassertion
I
OC
= 5mA
V
OC
= 5V
4
15
0.4
1
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QW-R502-568.B
US3X77
FUNCTIONAL DESCRIPTION
CMOS IC
OVERCURRENT PROTECTION
When the output load exceeds the current-limit threshold, The Over Current Protection will be triggered. The
typical current limit value of UTC
US3077/US3277/US3377/US3477
is 1A, 1.5A, 2A, 2.5A. There is foldback of
current limit when short-circuit being encountered.
OC RESPONSE
The OC open-drain output is asserted (active low) when an over current or over-temperature shutdown condition
is encountered after a 9-ms deglitch timeout. The output remains asserted until the over-current or over-temperature
condition is removed.
THERMAL SHUTDOWN
Thermal shutdown protects UTC
US3X77
from excessive power dissipation. If the die temperature exceeds 135°C,
the MOSFET switch is shut off. 20°C of hysteresis prevents the switch from turning on until the die temperature
drops to 115°C. Thermal shutdown circuit functions only when the switch is enabled.
UNDERVOLTAGE LOCKOUT (UVLO)
UVLO (under-voltage lockout) prevents the output MOSFET from turning on until IN (input voltage) exceeds 2.5V
typically. After the switch turns on, if the voltage drops below 2.3V typically, UVLO shuts off the output MOSFET.
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www.unisonic.com.tw
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QW-R502-568.B
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