NSC LM3526-HMWC Datasheet
LM3526
Dual Port USB Power Switch and Over-Current
Protection
General Description
The LM3526 provides Universal Serial Bus standard power
switch and over-current protection for all host port applications. The dual port device is ideal for Notebook and desktop
PC’s that supply power to more than one port.
A 1 ms delay on the fault flag output prevents erroneous
overcurrent reporting caused by in-rush currents during
hot-plug events.
The dual stage thermal protection circuit in the LM3526 provides individual protection to each switch and the entire device. In a short-circuit/over-current event, the switch dissipating excessive heat is turned off, allowing the second switch
to continue to function uninterrupted.
The LM3526 accepts an input voltage between 2.7V and
5.5V allowing use as a device-based in-rush current limiter
for 3.3V USB peripherals, as well as Root and Self-Powered
Hubs at 5.5V. The Enable inputs accept both 3.3V and 5.0V
logic thresholds.
The small size, low R
ON
, and 1 ms fault flag delay make the
LM3526 a good choice for root hubs as well as per-port
power control in embedded and stand-alone hubs.
Features
n 1 ms fault flag delay filters Hot-Plug events
n Smooth turn-on eliminates in-rush induced voltage drop
n UL recognized component: REF
#
205202
n 1A nominal short circuit output current protects PC
power supplies
n Thermal shutdown protects device in direct short
condition
n 500mA minimum continuous load current
n Small SO-8 package minimizes board space
n 2.7V to 5.5V input voltage range
n 140 mΩ Max. switch resistance
n 1 µA Max. standby current
n 200 µA Max. operating current
n Under-voltage lockout (UVLO)
Applications
n Universal Serial Bus (USB) Root Hubs including
Desktop and Notebook PC
n USB Monitor Hubs
n Other Self-Powered USB Hub Devices
n High Power USB Devices Requiring In-rush Limiting
n General Purpose High Side Switch Applications
Typical Operating Circuit and Connection Diagram
DS101097-1
DS101097-2
LM3526-H
DS101097-40
DS101097-28
LM3526-L
February 2000
LM3526 Dual Port USB Power Switch and Over-Current Protection
© 2000 National Semiconductor Corporation DS101097 www.national.com
Ordering Information
Part Number Enable, Delivery Option Package Type
LM3526M-H Active High Enable, 95 units per rail
SO-8,
NS Package
Number M08A
LM3526M-L Active Low Enable, 95 units per rail
LM3526MX-H Active High Enable, 2500 units per reel
LM3526MX-L Active Low Enable, 2500 units per reel
LM3526
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Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage −0.3V to 6V
Output Voltage −0.3V to 6V
Voltage at All Other Pins −0.3V to 5.5V
Power Dissipation (T
A
= 25˚C)
(Note 2) 700 mW
T
JMAX
(Note 2) 160˚C
Operating Ratings
Supply Voltage Range 2.7V to 5.5V
Operating Ambient Range −40˚C to 85˚C
Operating Junction Temperature
Range −40˚C to 125˚C
Storage Temperature Range −65˚C to +150˚C
Lead Temperature
(Soldering, 5 seconds) 260˚C
ESD Rating (Note 3)
ESD Rating Output Only
2kV
8kV
DC Electrical Characteristics
Limits in standard typeface are for T
J
=
25˚C, and limits in boldface type apply over the full operating temperature range. Un-
less otherwise specified: V
IN
=
5.0V, V
EN
=
0V (LM3526-L) or V
EN
=
V
IN
(LM3526-H).
Symbol Parameter Conditions Min Typ Max Units
R
ON
On Resistance
V
IN
=
5V, I
OUT
=
500mA, each switch 100 140
mΩ
V
IN
=
2.7V, I
OUT
=
500mA, each switch 110 180
I
OUT
OUT pins continuous
output current
Each Output 0.5 A
I
SC
Short Circuit Output
Current
Each Output (enable into Load) (Note 4)
V
OUT
=
4.0V
V
OUT
=
0.1V
0.5 1.2
1
1.9
1.5
A
OC
THRESH
Over-current Threshold 2.2 3.2 A
I
LEAK
OUT pins Output
Leakage Current
VEN=VIN(LM3526-L)
VEN= 0V (LM3526-H)
0.01 10 µA
R
FO
FLAG Output Voltage
I
FO
= 10 mA, V
IN
=
5.0V 10 25
ΩI
FO
= 10 mA, V
IN
=
3.3V 11 35
I
FO
= 10 mA, V
IN
=
2.7V 12 40
I
EN
EN/EN Leakage Current VEN/VEN=0VorVEN/VEN=V
IN
−0.5 0.5 µA
V
IH
EN/EN Input Logic High (Note 5) 2.4 1.9 V
V
IL
EN/EN Input Logic Low (Note 5) 1.7 0.8 V
V
UVLO
Under-Voltage Lockout
Threshold
1.8 V
I
DDOFF
Supply Current Switch-Off
−40˚C ≤ T
J
≤ 85˚C
0.2 1
2
µA
I
DDON
Supply Current Switch-On 115 200 µA
Th
SD
Over-temperature
Shutdown Threshold
TJIncreasing, with no shorted output
T
J
Increasing, with shorted output (s)
T
J
Decreasing (Note 4)
150
145
135
˚C
I
FH
Error Flag Leakage
Current
V
flag
=
5V 0.01 1 µA
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Electrical specifications do not apply when operating the device
beyond its rated operating conditions.
Note 2: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
JMAX
(Maximum junction temperature), θJA(junction to am-
bient thermal resistance), andT
A
(ambient temperature). The maximumallowablepower dissipation at any temperature is P
DMAX
=
(T
JMAX−TA
)/θJAor the number
given in the Absolute Maximum Ratings, which ever is lower. θ
JA
=
150˚C/W.
Note 3: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. Enable pin ESD threshold is 1.7kV.
Note 4: Thermal Shutdown will protect the device from permanent damage.
Note 5: For LM3526-L, OFF is EN ≥ 2.4V and ON is EN ≤ 0.8V. For LM3526-H, OFF is EN ≤ 0.8V and ON is EN ≥ 2.4V.
LM3526
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AC Electrical Characteristics
Limits in standard typeface are for T
J
=
25˚C, and limits in boldface type apply over the full operating temperature range. Un-
less otherwise specified: V
IN
=
5.0V.
Symbol Parameter Conditions Min Typ Max Units
t
r
OUT Rise Time RL=10Ω 100 µs
t
f
OUT Fall Time RL=10Ω 5µs
t
ON
Turn on Delay, EN to OUT RL=10Ω 150 µs
t
OFF
Turn off Delay, EN to OUT RL=10Ω 5µs
t
OC
Over Current Flag Delay RL=0 1 ms
Pin Description
Pin Number Pin Name Pin Function
1, 4 ENA, ENB
(LM3526-L)
ENA, ENB
(LM3526-H)
Enable (Input): Logic-compatible enable inputs.
2, 3 FLAG A
FLAG B
Fault Flag (Output): Active-low, open-drain outputs. Indicates overcurrent, UVLO or thermal
shutdown.
*
See application section for more information.
6 GND Ground
7 IN Supply Input: This pin is the input to the power switch and the supply voltage for the IC.
8, 5 OUT A
OUT B
Switch Output: These pins are the outputs of the high side switch.
Typical Application Circuit
DS101097-3
LM3526
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