National Semiconductor LM3526 Technical data

LM3526
Dual Port USB Power Switch and Over-Current
Protection

LM3526 Dual Port USB Power Switch and Over-Current Protection

March 2005

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 hot­plug 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
LM3526 a good choice for root hubs as well as per-port
power control in embedded and stand-alone hubs.

, and 1 ms fault flag delay make the

ON

Features

n Compatible with USB1.1 and USB 2.0
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

LM3526-H

10109701

LM3526-L

© 2005 National Semiconductor Corporation DS101097 www.national.com

10109702

10109740

10109728

Ordering Information

LM3526

Part Number Enable, Delivery Option Package Type

LM3526M-H Active High Enable, 95 units per rail

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

SO-8,

NS Package Number

M08A

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LM3526

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

= 25˚C)

A

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

(Note 2) 700 mW

(Note 2) 150˚C

T

JMAX

Operating Ratings

Supply Voltage Range 2.7V to 5.5V

Operating Ambient Range −40˚C to 85˚C

DC Electrical Characteristics

Limits in standard typeface are for TJ= 25˚C, and limits in boldface type apply over the full operating temperature range. Un­less otherwise specified: V

Symbol Parameter Conditions Min Typ Max Units

R

I

ON

OUT

On Resistance

OUT pins continuous
output current

I

SC

Short Circuit Output
Current

OC

I

LEAK

THRESH

Over-current Threshold 2.2 3.2 A

OUT pins Output Leakage
Current

R

I

V

V

V

FO

EN

IH

IL

UVLO

FLAG Output Voltage

EN/EN Leakage Current VEN/VEN=0VorVEN/VEN=V

EN/EN Input Logic High (Note 5) 2.4 1.9 V

EN/EN Input Logic Low (Note 5) 1.7 0.8 V

Under-Voltage Lockout
Threshold

I

DDOFF

I

DDON

Th

SD

Supply Current Switch-Off

Supply Current Switch-On 115 200 µA

Over-temperature
Shutdown Threshold

I

FH

Error Flag Leakage
Current

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
ambient thermal resistance), and T
number given in the Absolute Maximum Ratings, which ever is lower. θ

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.

= 5.0V, VEN= 0V (LM3526-L) or VEN=VIN(LM3526-H).

IN

V

IN

V

IN

= 5V, I

= 2.7V, I

= 500mA, each switch 100 140

OUT

= 500mA, each switch 110 180

OUT

Each Output 0.5 A

Each Output (enable into Load) (Note 4)

= 4.0V

V

OUT

= 0.1V

V

OUT

0.5 1.2

VEN=VIN(LM3526-L)
VEN= 0V (LM3526-H)

= 10 mA, VIN= 5.0V 10 25

I

FO

= 10 mA, VIN= 3.3V 11 35

FO

I

= 10 mA, VIN= 2.7V 12 40

FO

−0.5 0.5 µA

−40˚C ≤ T

≤ 85˚C

J

IN

TJIncreasing, with no shorted output

Increasing, with shorted output (s)

T

J

Decreasing (Note 4)

T

J

V

= 5V 0.01 1 µA

flag

(Maximum junction temperature), θJA(junction to

(ambient temperature). The maximum allowable power dissipation at any temperature is P

A

= 150˚C/W.

JA

JMAX

1.9

1

1.5

0.01 10 µA

1.8 V

0.2 1

2

150
145
135

DMAX

=(T

JMAX−TA

)/θJAor the

2kV
8kV

mΩ

A

ΩI

µA

˚C

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AC Electrical Characteristics

Limits in standard typeface are for TJ= 25˚C, and limits in boldface type apply over the full operating temperature range. Un-

LM3526

less otherwise specified: V

= 5.0V.

IN

Symbol Parameter Conditions Min Typ Max Units

t

t

t

t

t

r

f

ON

OFF

OC

OUT Rise Time RL=10Ω 100 µs

OUT Fall Time RL=10Ω 5µs

Turn on Delay, EN to OUT RL=10Ω 150 µs

Turn off Delay, EN to OUT RL=10Ω 5µs

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)

2, 3 FLAG A

FLAG B

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

Enable (Input): Logic-compatible enable inputs.

Fault Flag (Output): Active-low, open-drain outputs. Indicates overcurrent, UVLO or thermal
shutdown. *See application section for more information.

Switch Output: These pins are the outputs of the high side switch.

Typical Application Circuit

10109703

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