UNISONIC TECHNOLOGIES CO., LTD
US211/A/B/C
Preliminary
CMOS IC
HIGH-SIDE POWER SWITCHES
WITH FLAG
DESCRIPTION
The UTC
US211/A/B/C
series are 80mΩ high-side power
switches. There’s internal single low voltage N-Channel MOSFET
which makes it an ideal for all USB applications. This MOSFET
should be driven by a charge pump circuitry inside. Its switch on
resistance is as low as 80mΩ which we know specially meets the
drop voltage for USB applications.
The flag pin can output an open-drain fault flag to next controller.
There’re lots internal special ways for protecting the chip’s
operation.
When in hot-plug events, there’s large current which can create
the upstream voltage droop to match the USB’s voltage droop
requirements and soft-start for isolating the power source.
As soon as the die temperature is higher than 130℃, the internal
shutdown circuit will work.
Only when there’s a normal input voltage in the V
IN
pin, the
UVLO (under-voltage lockout, 1.3V/2.5V typ.) can make sure the
chip is till in the off state.
Because of the requirement of USB power the fault current
should be ensured less than 0.6A/1.1A (UTC
US211/A,
single port)
and 1.3A /1.5A (UTC
US211B/C,
dual ports).
FEATURES
* 80mΩ(Typ) N-Channel MOSFET
* Supply Current:
–
Switch On : 25μA(Typ)
–
Switch Off : 1μA (Typ)
* Load Current 500mA for US211 and 1.0A for US211A/B/C
* Input Voltage from 2V ~ 5.5V
* In Off-State: Output Voltage can be Higher than Input
ORDERING INFORMATION
Ordering Number
Lead Free
Halogen Free
US211XXL-AF5-R
US211XXG-AF5-R
Package
SOT-25
Packing
Tape Reel
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QW-R502-A67.a
US211/A/B/C
MARKING
5
Current Code:
1: 0.6A, A: 1.1A,
B: 1.3A, C: 1.5A
U1
1
2
3
4
Preliminary
CMOS IC
G: Halogen Free
L : Lead Free
Logic Level Enable Pin
PIN CONFIGURATION
V
OUT
5
V
IN
4
1
CTL
2
GND
3
FLG
PIN DESCRIPTION
PIN NAME
CTL
GND
FLG
PIN NO
1
2
3
4
5
DESCRIPTION
Enable Input pin, H: High active, L: Low active
Ground
Open-drain fault flag output
Power input voltage
Output voltage
V
IN
V
OUT
BLOCK DIAGRAM
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US211/A/B/C
PARAMETER
Supply Voltage
VCTL
V FLG
Junction Temperature
Preliminary
SYMBOL
V
CC
V
CTL
V
FLG
T
J
RATINGS
6.5
+2 ~ +5.5 (Note 2)
-0.3~ +6.5
0 ~ +5.5 (Note 2)
6.5
CMOS IC
UNIT
V
V
V
V
V
ABSOLUTE MAXIMUM RATING
(T
A
=25°C, unless otherwise specified)
Input/Output Pins
150
°C
-20 ~ +100 (Note 2)
°C
Storage Temperature
T
STG
-65 ~ +150
°C
Notes:1. 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.
2. The device is not guaranteed to function when it’s beyond its operating conditions.
THERMAL DATA
SYMBOL
θ
JA
θ
JC
SYMBOL
Low
High
V
IL
V
IH
I
I(CTL)
V
UVLO
∆V
UVLO
I
SW(ON)
I
SW(OFF)
I
O(LEAK)
RATINGS
260
81
MIN
UNIT
°C/W
°C/W
TYP MAX UNIT
0.8
2.0
0.01
1.0
2.1
2.5
0.1
25
0.1
0.5
0.6
1.1
1.3
1.5
0.8
1.5
1.7
2.0
0.8
1.0
1.0
1.3
80
80
400
2.9
V
V
µA
V
V
45
1
10
1.1
1.9
2.1
2.4
µA
µA
µA
A
A
A
A
A
A
A
A
mΩ
mΩ
µs
PARAMETER
Junction to Ambient
Junction to Case
ELECTRICAL CHARACTERISTICS
TEST CONDITIONS
V
IN
=2V~5.5V, Switch OFF
V
IN
=2V~5.5V, Switch ON
V
CTL
=0V~5.5V
V
IN
increasing
V
IN
decreasing
Switch on, V
OUT
=OPEN
Switch off, V
OUT
=OPEN
V
CTL
=0V, R
LOAD
=0Ω
US211
US211A
US211B
US211C
US211
V
OUT
=0V, measured prior to US211A
thermal shutdown
US211B
US211C
I
OUT
= 500mA
I
OUT
=1.0A
10% ~ 90% of V
OUT
rising
US211
US211A/B/C
US211/ US211A
US211B/ US211C
PARAMETER
ENABLE INPUT
CTL Threshold
CTL Input Current
UNDER VOLTAGE LOCK
Under-Voltage Lockout
Under-Voltage Hysteresis
SUPPLY CURRENT
Supply Current
Output Leakage Current
CURRENT LIMIT
Current Limit
I
LIMIT
Short Circuit Fold-Back Current
I
SC(FB)
POWER SWITCH
Switch ON Resistance
Output Turn-ON Rise Time
OVER CURRENT FLAG
FLAG OFF Current
R
DS(ON)
t
ON
(
RISE
)
110
110
I
FLG(OFF)
V
FLG
=5V
I
SINK
=1mA
From fault condition to FLG assertion
2
0.01
20
10
130
20
1
400
15
µA
Ω
ms
°C
°C
3 of 8
FLAG Output Resistance
FLAG Delay Time
THERMAL SHUTDOWN
Thermal Shutdown Protection
Thermal Shutdown Hysteresis
R
FLG
t
D
T
SD
∆T
SD
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QW-R502-A67.a
US211/A/B/C
APPLICATION INFORMATION
Input and Output
Preliminary
CMOS IC
V
IN
(input) is the power source connection to the internal circuitry and the drain of the MOSFET. V
OUT
(output) is
the source of the MOSFET. In a typical application, current flows through the switch from V
IN
to V
OUT
toward the load.
Because the MOSFET is bidirectional when on, if V
OUT
is greater than V
IN
, current will flow from V
OUT
to V
IN
There is no a parasitic body diode of N-MOSFET between the drain and source compared to a normal MOSFET,.
The
US211
can protect damage from reverse current flow if V
OUT
being externally forced to a higher voltage than V
IN
when the output disabled (V
EN
> 2V).
Enable Input
The switch will be disabled when the EN pin is in a logic low/high condition. During this condition, the internal
circuitry and MOSFET are turned off, reducing the supply current to 0.1μA typical. Floating the EN may cause
unpredictable operation. EN should not be allowed to go negative with respect to GND. The EN pin may be directly
tied to V
IN
(GND) to keep the part on.
Soft Start for Hot Plug-In Applications
When hot-plug events occur, the soft start is used to eliminate the upstream voltage droop due to the inrush
current. The soft-start protects power supplies from damage caused by highly capacitive loads.
Fault Flag
The fault flag is an open-drained output of an N-channel MOSFET. The flag drops low to indicate fault conditions:
current limit, thermal shutdown or V
OUT
< V
IN
−
1V. In order to reduce energy drain, a large pull-up resistor is required.
100kΩ pull-up resistor is recommended for most applications.
In the case of over current condition, the fault flag is active only if the flag response delay time (t
D
) has elapsed.
This ensures that FLG is asserted only upon valid over-current conditions and that erroneous error reporting is
eliminated. For example, false over-current conditions may occur during hot-plug events when extremely large
capacitive loads are connected and causes a high transient inrush current that exceeds the current limit threshold.
The FLG response delay time t
D
is typically 10ms.
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US211/A/B/C
Preliminary
CMOS IC
APPLICATION INFORMATION(Cont.)
Current Limiting and Short-Circuit Protection
The current limit circuit protects the MOSFET switch and the hub downstream port from damage. This circuit can
deliver load current up to the current limit threshold of typically 0.8A through the switch of US211, 1.5A for US211A,
1.7A for US211B and 2.0A for US211C. When an enabled switch applies a heavy load or short circuit, a
large-desired transient current occurs which can cause the current limit circuit response. If this current becomes
higher than the current limit threshold, the devices enter constant current mode until thermal shutdown occurs or the
fault is removed.
Thermal Shutdown
The thermal shutdown circuit is used to prevent damage occurs when the die temperature becomes higher than
approximately 130°C. After 20°C of hysteresis, the switch will automatically restart if it enabled. When these devices
are disabled or the fault is removed, the output and
FLG
signal will continue to cycle on and off.
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