Datasheet

UNISONIC TECHNOLOGIES CO., LTD
US251
Preliminary
CMOS IC
CURRENT-LIMITED,
POWER-DISTRIBUTION
SWITCHES

DESCRIPTION
The UTC US251 is a power distribution switch. It is intended for
applications such as USB where heavy capacitive loads and
short-circuits are likely to be encountered. This family offers
multiple devices with fixed current-limit thresholds for applications
between 0.5A and 2A.
The RDS(ON) of the MOSFET switch is as low as 80mΩ. OC is
open-drain output report over-current or over-temperature event
which has deglitch typical 9ms timeout period typically 9ms.
The UTC US251 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 UTC US251 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.

FEATURES
* Single Power Switch Family
* 80-mΩ High-Side MOSFET
* Rated currents of 0.5 A, 1 A, 1.5 A, 2 A
* Accurate, Fixed, Constant Current Limit
* Deglitched Fault Reporting
* Output Discharge When Disabled
* Reverse Current Blocking
* Built-in Softstart

ORDERING INFORMATION
Ordering Number
US251G-xx-AF5-R
Package
SOT-25
Packing
Tape Reel
US251G-xx-AF5-R
(1)Packing Type
(1) R: Tape Reel
(2)Package Type
(2) AF5: SOT-25
(3)Current Limit
(3) 08: 0.8mA, 16: 1.6mA, 22: 2.2mA, 29: 2.9mA
(4)Green Package
(4) G: Halogen Free and Lead Free
www.unisonic.com.tw
Copyright © 2015 Unisonic Technologies Co., Ltd
1 of 5
QW-R129-008.a
US251
Preliminary

MARKING

PIN CONFIGURATION
IN
EN
4
5

1
2
3
OUT
GND
OC
PIN DESCRIPTION
PIN NO.
1
2
PIN NAME
OUT
GND
3
OC
4
EN or EN
IN
5

CMOS IC
DESCRIPTION
Output MOSFET Source of switch.
Ground
Open-Drain OC output.
Enable input. Make sure EN pin never floating.
Power Input Voltage
BLOCK DIAGRAM
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
2 of 5
QW-R129-008.a
US251

Preliminary
CMOS IC
ABSOLUTE MAXIMUM RATING
PARAMETER
SYMBOL
RATINGS
UNIT
Supply Voltage
VIN
-0.3 ~ 6
V
Enable Input Voltage
VEN
-0.3 ~ 6
V
Flag Voltage
VEN
-0.3 ~ 6
V
Output Voltage
VOUT
-0.3 ~ 6
V
Output Current
IOUT
Internally Limited
A
Junction Temperature
TJ
150
°C
Storage Temperature
TSTG
-65~ +150
°C
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.

THERMAL DATA
PARAMETER
Junction to Ambient

SYMBOL
θJA
RATINGS
250
UNIT
℃/W
RECOMMENDED OPERATING CONDITIONS
PARAMETER
Input Voltage, IN
SYMBOL
VIN
TEST CONDITIONS
MIN
3.5
TYP
MAX
5.5
UNIT
V
Input Voltage, EN or EN
Operating Junction Temperature
VEN
0
5.5
V
TJ
-40
125
°C
Sink Current Into FLT
IFLT
0
5
mA
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
3 of 5
QW-R129-008.a
US251

Preliminary
CMOS IC
ELECTRICAL CHARACTERISTICS
(VIN=5V, CIN=COUT=1μF, TA=25°C, unless otherwise specified)
PARAMETER
SYMBOL
TEST CONDITIONS
ENABLE INPUT
Low
VIL
VIN=3.5V~5.5V, Switch OFF
CTL Threshold
High
VIH
VIN=3.5V~5.5V, Switch ON
CTL Input Current
II(CTL)
VCTL=0V~5.5V
UNDER VOLTAGE LOCK
Under-Voltage Lockout
VUVLO
VIN increasing
Under-Voltage Hysteresis
∆VUVLO
VIN decreasing
SUPPLY CURRENT
ISW(ON)
Switch on, VOUT=OPEN
Supply Current
Switch off, VOUT=OPEN
ISW(OFF)
Output Leakage Current
IO(LEAK)
VCTL=0V, RLOAD=0Ω
VOUT=5V, VIN=0V, measure IVOUT
Reverse Leakage Current
IREV
-40°C≤ (TJ, TA)≤85°C, VOUT=5V, VIN=0V,
measure IVOUT
CURRENT LIMIT
US251-08
US251-16
Current Limit
ILIMIT
US251-22
US251-29
US251-08
VOUT=0V, measured prior US251-16
ISC(FB)
Short Circuit Fold-Back Current
to thermal shutdown
US251-22
US251-29
POWER SWITCH
IOUT=0.5A
US251-08
IOUT=1.0A
US251-16
Switch ON Resistance
RDS(ON)
IOUT=1.5A
US251-22
IOUT=2.0A
US251-29
tON(RISE)
10% ~ 90% of VOUT rising
Output Turn-ON Rise Time
OVER CURRENT FLAG
I FLG(OFF)
V FLG =5V
FLAG OFF Current
RFLG
ISINK=1mA
FLAG Output Resistance
FLAG Delay Time
tD
From fault condition to FLG assertion
MIN
TYP MAX UNIT
0.8
0.01
V
V
µA
2.8
0.1
V
V
2.0
55
0.1
0.5
0.1
0.6
1.2
1.6
2.3
70
1
10
1
µA
µA
µA
µA
5
µA
0.8
1.6
2.2
2.9
1
1
1
1
1.1
1.9
2.7
3.6
A
A
A
A
A
A
A
A
80
80
80
80
400
110
110
110
110
mΩ
mΩ
mΩ
mΩ
µs
0.01
20
1
400
µA
Ω
10
ms
THERMAL SHUTDOWN
Thermal Shutdown Protection
TSD
130
℃
Thermal Shutdown Hysteresis
∆TSD
20
℃
Output Discharge
Output Pull-Down Resistance
RPD
VIN=VOUT=5.0V, disabled
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
400
800
Ω
4 of 5
QW-R129-008.a
US251

Preliminary
CMOS IC
TYPICAL APPLICATION CIRCUIT
VIN
RFLT
10kΩ
IN
OUT
VOUT
150µF
0.1µF
Fault Signal
OC
Control Signal
EN of EN
GND
UTC assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or
other parameters) listed in products specifications of any and all UTC products described or contained
herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in
whole or in part is prohibited without the prior written consent of the copyright owner. The information
presented in this document does not form part of any quotation or contract, is believed to be accurate
and reliable and may be changed without notice.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
5 of 5
QW-R129-008.a
Similar pages