NSC LM3544MX-H, LM3544M-L, LM3544M-H, LM3544MX-L Datasheet

LM3544
Quad Port USB Power Distribution Switch and
Over-Current Protection

LM3544 Quad Port USB Power Distribution Switch and Over-Current Protection

March 2001

General Description

The LM3544 is a quad high-side power switch that is an
excellent choice for use in Root, Self-Powered and
Bus-Powered USB (Universal Serial Bus) Hubs. Indepen­dent port enables, flag signals to alert USB controllers of
error conditions, controlled start-up in hot-plug events, and
short circuit protection all satisfy USB requirements.

The LM3544 accepts input voltages between 2.7V and 5.5V.
The Enable logic inputs, available in active-high and
active-low versions, can be powered off any voltage in the

2.7V to 5.5V range. The LM3544 limits the continuous
current through a single port to 1.25A (max.) when it is
shorted to ground.

The low on-state resistance of the LM3544 switches ensures
the LM3544 will satisfy USB voltage drop requirements,
even when current through a switch reaches 500 mA. Thus,
High-Powered USB Functions, Low-Powered USB func­tions, and Bus-Powered USB Hubs can all be powered off a
Root or Self-Powered USB Hub containing the LM3544.

Added features of the LM3544 include current foldback to
reduce power consumption in current overload conditions,
thermal shutdown to prevent device failure caused by
high-current overheating, and undervoltage lockout to keep
switches from operating if the input voltage is below
acceptable levels.

Features

n 90mΩ (typ.) High-Side MOSFET Switch
n 500mA Continuous Current per Port
n 7 ms Fault Flag Delay Filters Hot-Plug Events
n Industry Standard Pin Order
n Short Circuit Protection with Power-Saving Current

Foldback

n Thermal Shutdown Protection
n Undervoltage Lockout
n Recognized by UL and Nemko CB
n Input Voltage Range: 2.7V to 5.5V
n 5µA Maximum Standby Supply Current
n 16-Pin SOIC Package
n Ambient Temperature Range: −40˚C to 85˚C

Applications

n USB Root, Self-Powered, and Bus-Powered Hubs
n USB Devices such as Monitors and Printers
n General Purpose High Side Switch Applications

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Functional Diagram

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© 2001 National Semiconductor Corporation DS101208 www.national.com

Connection Diagrams

LM3544

LM3544-H

16-Pin SOIC

LM3544-L

16-Pin SOIC

Top View

10120802

Ordering Information

Part Number Enable, Delivery Option Package Type

LM3544M-H Active High Enable

LM3544M-L Active Low Enable
LM3544MX-H Active High Enable, 2500 units per reel
LM3544MX-L Active Low Enable, 2500 units per reel

Typical Application Circuit

Top View

10120829

SO-16

NS Package Number M16A

FIGURE 1. The LM3544 used in a Self-Powered or Root USB Hub

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LM3544

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales

Lead Temperature Range
(Soldering, 5 sec.) 260˚C

ESD Rating (Note 3) 2 kV

Office/Distributors for availability and specifications.

Voltage at IN
Voltage at EN

pins
Power Dissipation (Note 2) Internally Limited
Maximum Junction Temperature 150˚C
Storage Temperature Range −65˚C to 150˚C

and OUTXpins −0.3V to 6V

X

(ENX) and FLAG

X

X

−0.3V to 5.5V

Operating Ratings

Supply Voltage Range 2.7V to 5.5V
Continuous Output Current Range

(Each Output) 0 mA to 500 mA
Junction Temperature Range −40˚C to 125˚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
OUTXContinuous Output

Current

I

LEAK-OUT

I

SC

OUTXLeakage Current ENX= 0 (ENX=VIN);

OUTXShort-Circuit Current
(Note 4)

OC

THRESH

V

L_FLAG

I

LEAK-FLAG

I

LEAK-EN

V

IH

V

IL

V

UVLO

I

DDON

I

DDOFF

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 allowable power dissipation isafunctionof the Maximum Junction Temperature(T
the Ambient Temperature (T
at any temperature is P
thermal shutdown.

Note 3: The Human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin.
Note 4: Thermal Shutdown will protect the device from permanent damage.

Overcurrent Threshold 2.0 3.2 A
FLAGXOutput-Low Voltage I(FLAGX)=10mA 0.1 0.3 V
FLAGXLeakage Current 2.7 ≤ V
ENxInput Leakage Current ENx/ENx=0Vor

EN/EN Input Logic High 2.7V ≤ VIN≤ 5.5V 2.4 V
EN/EN Input Logic Low 4.5V ≤ VIN≤ 5.5V 0.8 V

Under-Voltage Lockout
Threshold

Operational Supply Current

Shutdown Supply Current

MAX

= 5.0V, ENX=VIN(LM3544-H) or ENX= 0V (LM3544-L).

IN

V

IN

V

IN

= 5V, I
= 3.3V, I

= 0.5A 90 125

OUTX

OUTX

3.0V ≤ VIN≤ 5.5V 0.5 A

TJ= 25˚C
EN

= 0 (ENX=VIN);

X

−40≤TJ≤125˚C
OUTXConnected to GND 0.8 1.25 A

≤ 5.5V 0.2 1 µA

FLAG

ENx/ENx=V

2.7V ≤ V

EN

x=VIN

IN

≤ 4.5V 0.4 V

IN

(ENx=0);

TJ= 25˚C
EN

x=VIN

(ENx=0);

−40˚C ≤ TJ≤ 125˚C
= 0 (ENx=VIN);

EN

x

TJ= 25˚C

−40˚C ≤ T

). The LM3544 in the 16-pin SOIC package has a T

A

=(T

)/θJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the part will go into

JMAX−TA

≤ 125˚C 5 µA

J

of 150˚C and a θJAof 130˚C/W. The maximum allowable power dissipation

JMAX

= 0.5A 95 130

0.01 1 µA

10 µA

−0.5 0.5 µA

1.8 V

375 600 µA

800 µA

1µA

), Junction to Ambient Thermal Resistance (θJA), and

JMAX

mΩ

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AC Electrical Characteristics

Limits are for TJ= 25˚C and VIN= 5.0V.

LM3544

Symbol Parameter Conditions Min Typ Max Units

t

r

t

f

t

ON

t

OFF

t

F

Note 5: Time for OUTxto rise from 10% to 90% of its enabled steady-state value after ENx(ENx) is asserted.
Note 6: Time for OUTxto fall from 10% to 90% of its enabled steady-state value after ENx(ENx) is deasserted.
Note 7: Time between ENxrising through VIH(ENxfalling through VIL) and OUTxrising through 90% of its enabled steady-state voltage.
Note 8: Time between ENxfalling through VIL(ENxrising through VIH) and OUTxfalling through 10% of its enabled steady-state voltage.
Note 9: Time between ENxrising through VIN(ENxfalling through VIN) and FLAGXfalling through 0.3V when OUTXis connected to GND.

OUTxRise Time (Note 5) CL= 33 µF, I
OUTxFall Time (Note 6) CL= 33 µF, I
Turn-on Delay (Note 7) CL= 33 µF, I
Turn-off Delay (Note 8) CL= 33 µF, I
Flag Delay (Note 9) I

=10mA 7 ms

FLAG

= 500 mA 1.5 ms

LOAD

= 500 mA 0.9 ms

LOAD

= 500 mA 2.9 ms

LOAD

= 500 mA 0.7 ms

LOAD

Pin Description

Pin Number Pin Name Pin Function

2, 6 IN 1, 2 Supply Inputs: These pins are the inputs to the power switches and the supply

input for the IC. In most applications they are connected together externally
and to a single input voltage supply.

1, 5 GND 1, 2 Grounds: Must be connected together and to a common ground.

15, 14, 11, 10 OUT 1, 2, 3, 4 Switch Outputs: These pins are the outputs of the high side switches.

3, 4, 7, 8 LM3544-H: EN 1, 2, 3, 4

(LM3544-L: EN 1, 2, 3, 4)

16, 13, 12, 9 FLAG 1, 2, 3, 4 Fault Flag (Outputs): Active-low open drain outputs. Indicates over-current,

Enable (Inputs): Active-high (or active-low) logic enable inputs.

UVLO or thermal shutdown. See ″Application Information″ section for more
details.

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