UNISONIC TECHNOLOGIES CO., LTD
US205
Preliminary
CMOS IC
100mΩ, 2A SLEW RATE
CONTROLLED LOAD SWITCH
DESCRIPTION
The UTC
US205
is a cost-effective, low-voltage, low switch-on
resistance (typ. 100mΩ) high-side Power Switch IC. It has a 20μA
low quiescent supply current that meets the requirements of
battery-powered portable equipment.
The UTC
US205
incorporates protection circuits, such as an
over-current protection circuit, a short fold back circuit, a thermal
shutdown circuit and an under-voltage lockout circuit for overall
protection. Besides, a slew rate controlled function is embedded for
turn-on rising time control.
The UTC
US205
can be usedin applications, such as Cellular
Phones, Digital still Camera, Hot swap Supplies, Notebook
Computers, Personal Communication Devices, Personal Digital
Assistants and so on.
The UTC
US205
is available in SOP-8 package.
FEATURES
* High-Side NMOSFET: 100mΩ (TYP)
* Input Voltage Varies From 2.7V to 5.5V
* Low Supply Current: 20μA
* Over Current Protection
* Short Circuit Protection
* Under Voltage Lockout
* Thermal Protection with Foldback
* Slew Rate Limited Turn-On Time 3ms (5V)
* Reverse Blocking Current
* RoHS Compliant
ORDERING INFORMATION
Ordering Number
Lead Free
US205XL-S08-R
Halogen Free
US205XG-S08-R
Package
SOP-8
Packing
Tape Reel
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Copyright © 2011 Unisonic Technologies Co., Ltd
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QW-R502-609.A
US205
PIN CONFIGURATION
Preliminary
CMOS IC
PIN DESCRIPTION
PIN NO.
1
2
3
4
5, 6, 7, 8
PIN NAME
NC
V
OUT
EN
GND
V
IN
DESCRIPTION
No Internal Connection.
Power-Switch Output.
Chip Enable (Active High).
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Power Input Voltage.
BLOCK DIAGRAM
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PARAMETER
Preliminary
CMOS IC
ABSOLUTE MAXIMUM RATING
(T
A
=25°C, unless otherwise specified)
SYMBOL
RATINGS
UNIT
Supply Voltage
V
IN
6
V
Enable Input Voltage
EN
-0.3~6
V
Power Dissipation, @T
A
=25°C
P
D
0.3
W
Junction Temperature
T
J
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.
RECOMMENDED OPERATING CONDITIONS
(T
A
=25°C, unless otherwise specified) (Note)
SYMBOL
RATINGS
Supply Voltage
V
IN
2.7~5.5
Enable Input Voltage
EN
0~5.5
Junction Temperature
T
J
-40~100
Ambient Temperature
T
A
-40~85
Note: The device is not guaranteed to function outside its operating conditions.
PARAMETER
UNIT
V
V
°C
°C
ELECTRICAL CHARACTERISTICS
(V
IN
=5V, C
IN
=1uF, C
OUT
=0.1uF, T
A
=25°C, unless otherwise specified)
PARAMETER
SYMBOL
TEST CONDITIONS
Operation Voltage
V
IN
Under Voltage Lookout
V
UVLO
V
IN
Falling
Under Voltage Lockout Hysteresis
ΔV
UVLO
Quiescent Current
I
Q
EN=High
Off Supply Current
I
SHDN
EN=Low, V
OUT
=Open
Off Switch Current
I
LEAKAGE
EN=Low, V
OUT
=0
On-Resistance
R
DS(ON)
V
IN
=3.3V, I
OUT
=1.3A
Current Limiting
I
LIM
V
IN
=3.3V, V
OUT
=2.3V
V
OUT
=0V, Measured Prior
Short Circuit Current
I
SC_FB
to Thermal Shutdown
Thermal shutdown Threshold
T
SD
Thermal shutdown Hysteresis
ΔT
SD
Low
V
IL
V
IN
=2.7V ~ 5.5V
EN Threshold
High
V
IH
V
IN
=2.7V ~ 5.5V
Enable Input Leakage
I
EN
V
EN
=5.5V
Output Turn-On Delay Time
T
D_ON
V
IN
=5V, R
LOAD
=10Ω
Output Turn-On Rise Time
T
ON
V
IN
=5V, R
LOAD
=10Ω
Output Turn-Off Fall Time
T
D_OFF
V
IN
=5V, R
LOAD
=10Ω
Output Pull-Down Resistance During OFF R
DISCHARGE
EN=Low
MIN
2.7
1.3
TYP
1.7
50
20
MAX
5
2.1
70
1
1
120
2.5
1.5
UNIT
V
V
mV
μA
μA
μA
mΩ
A
A
°C
°C
V
V
μA
μs
ms
μs
Ω
1.5
0.4
100
2
0.8
130
20
0.8
2
60
3
4
150
1
100
10
1
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US205
APPLICATION INFORMATION
Preliminary
CMOS IC
The UTC
US205
is an enable input single N-MOSFET high-side power switches, optimized for self-powered and
bus-powered Universal Serial Bus (USB) applications. A charge pump circuitry is contained to drive the internal
MOSFET switch, the switch on resistance is 100mΩ, meets USB voltage droop requirements.
Input and Output
V
IN
(Input) is both the power supply connection for the internal circuitry driving the switch and the input (Drain
connection) of the power MOSFET switch. V
OUT
(Output) is the Source connection of the MOSFET and supplies
power to the load. In a typical circuit, current flows from V
IN
to V
OUT
toward the load. Since the switch is bidirectional
when enabled, if V
OUT
is greater than V
IN
, current will flow through the switch from V
OUT
to V
IN
.
There is no parasitic body diode between drain and source of the MOSFET, prevents reverse current flow if V
OUT
is externally forced to a higher voltage than V
IN
when the chip is disabled (V
EN
< 0.8V).
D
S
D
S
G
Normal MOSFET
G
UTC US205
Chip Enable Input
If the EN pin is in a logic low condition the UTC
US205
switch will be disabled. During this case, MOSFET and the
internal circuitry will be turned off, and the supply current is reduced to 0.1uA typical. When the EN is floating,
unpredictable operation may be caused. EN goes negative with respect to GND should not be allowed. The EN pin
can be directly tied to V
IN
.
Soft Start for Hot Plug-In Applications
The UTC
US205
“soft-start” feature eliminates the upstream voltage droop caused by the large inrush current
during hot-plug events, and effectively isolates the power source from extremely large capacitive load, meets the
USB voltage droop requirements.
Under-Voltage Lockout
The UTC
US205
internal Under-voltage lockout (UVLO) circuit prevents the MOSFET switch from turning on until
the input voltage exceeds approximately 1.75V. The internal MOSFET switch will be turned off if input voltage drops
below approximately 1.7V. Under-voltage detection functions only when the chip is enabled.
Current Limiting and Short-Circuit Protection
The UTC
US205
protects the power supply and the load from damage by the current limit circuitry, but can deliver
load current up to the current limit threshold (typically 2A). If an enabled switch encounters a heavy load or short
circuit case, a large transient current may flow until the current limit circuitry responds. Once this current limit
threshold level is exceeded, the device enters constant current mode until the fault is removed or thermal shutdown
occurs.
Supply Filter/Bypass Capacitor
To prevent the input voltage drooping during hot-plug events, a 1uF low-ESR ceramic capacitor from V
IN
to GND is
strongly recommended. But higher capacitor values will further reduce the voltage droop on the input. Furthermore,
without the bypass capacitor, an output short may cause sufficient ringing on the input (from source lead inductance)
to destroy the internal circuitry. The input voltage transient must not exceed the absolute maximum supply voltage
6V even for a short duration.
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US205
Preliminary
CMOS IC
APPLICATION INFORMATION(Cont.)
Output Filter Capacitor
A low-ESR 150uF aluminum electrolytic or tantalum between V
OUT
and GND is strongly recommended to meet the
330mV maximum droop requirement in the hub V
BUS
(Per USB 2.0, output ports must have a minimum 120μF of
low-ESR bulk capacitance per hub). The bypass capacitor itself should have a low dissipation factor to allow
decoupling at higher frequencies.
Thermal Shutdown
Thermal shutdown is used to turn off the output MOSFET when the if the temperature is higher than130°C, 20°C
of hysteresis prevents the switch turn on until the die temperature drops to 110°C.
TYPICAL APPLICATION CIRCUIT
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.
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