LM3525
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SNVS051D – FEBRUARY 2000 – REVISED MARCH 2013
LM3525 Single Port USB Power Switch and Over-Current Protection
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FEATURES
DESCRIPTION
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The LM3525 provides Universal Serial Bus standard
power switch and over-current protection for all host
port applications. The single port device is ideal for
Notebook PC and Handheld PC applications that
supply power to one port.
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Compatible with USB1.1 and USB 2.0
1 ms Fault Flag Delay During Hot-Plug Events
Smooth Turn-On Eliminates Inrush Induced
Voltage Drop
UL Recognized Component: REF # 205202
1A Nominal Short Circuit Output Current
Protects Notebook PC Power Supplies
Thermal Shutdown Protects Device in Direct
Short Condition
500mA Minimum Continuous Load Current
Small SOIC-8 Package Minimizes Board Space
2.7V to 5.5V Input Voltage Range
Switch Resistance ≤ 120 mΩ Max. at VIN = 5V
1µA Max Standby Current
100 µA Max Operating Current
Undervoltage Lockout (UVLO)
A 1 ms delay on fault flag output prevents erroneous
overcurrent reporting caused by inrush currents
during the hot-plug events.
The LM3525 accepts an input voltage between 2.7V
and 5.5V allowing use as a device-based inrush
current limiter for 3.3V USB peripherals, as well as
Root and Self-Powered Hubs at 5.5V. The Enable
input accepts both 3.3V and 5.0V logic thresholds.
The small size, low RON, and 1 ms fault flag delay
make the LM3525 a good choice for root hubs as well
as ganged power control in space-critical selfpowered hubs.
APPLICATIONS
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Universal Serial Bus (USB) Root Hubs
including Desktop and Notebook PC
USB Monitor Hubs
Other Self-Powered USB Hub Devices
High Power USB Devices Requiring Inrush
Limiting
General Purpose High Side Switch
Applications
Typical Operating Circuit and Connection Diagram
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2000–2013, Texas Instruments Incorporated
LM3525
SNVS051D – FEBRUARY 2000 – REVISED MARCH 2013
www.ti.com
Figure 1. LM3525M-L
Figure 2. LM3525M-H
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Absolute Maximum Ratings
(1) (2)
Supply Voltage
−0.3V to 6.0V
Output Voltage
−0.3V to 6.0V
Voltage at All Other Pins
−0.3V to 5.5V
Power Dissipation (TA = 25°C) (3)
TJMAX
(1)
(2)
(3)
700 mW
(3)
150°C
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. Products are not tested under negative Absolute Maximum conditions.
If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and
specifications.
The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX (maximum junction temperature),
θJA (junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any
temperature is PDMAX = (TJMAX − TA)/θJA or the number given in the Absolute Maximum Ratings, which ever is lower. The thermal
resistance θJA of the LM3525 in the SOIC-8 package is 150°C/W.
Operating Ratings
Supply Voltage Range
2.7 to 5.5V
−40°C to +85°C
Operating Ambient Range
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 (1)
(1)
2
2 kV
The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin.
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SNVS051D – FEBRUARY 2000 – REVISED MARCH 2013
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: VIN = 5.0V, EN = 0V (LM3525-L) or EN = VIN (LM3525-H).
Symbol
Parameter
Conditions
Min
Typ
Max
Units
80
120
120
160
mΩ
1.0
1.5
A
0.15
10
µA
2.25
3.2
A
IFO = 10 mA, VIN = 5V
6
25
IFO = 10 mA, VIN = 2.7V
8
40
IN to Out pins
VIN = 5V
VIN = 2.7V
RON
On-Resistance
IOUT
OUT pins continuous output current
ISC
Short Circuit Output Current
See (1)
ILEAK
OUT pins Output Leakage Current
EN = VIN (LM3525-L) or
EN = GND (LM3525-H),
OCTHRESH
Over-current Threshold
RFO
FLAG Output Resistance
IEN
EN/EN Leakage Current
EN/EN = 0V or EN/EN = VIN
−0.5
VIH
EN/EN Input Voltage
See (2)
2.4
VIL
EN/EN Input Voltage
See
(2)
VUVLO
Under-Voltage Lockout
VIN = Increasing
VIN = Decreasing
1.9
1.8
IDDOFF
Supply Current
Switch OFF
0.05
1
µA
IDDON
Supply Current
Switch ON
65
100
µA
ThSD
Overtemperature Shutdown
Threshold (1)
TJ Increasing
TJ Decreasing
135
125
IFH
Error Flag Leakage Current
VFLAG= 5V
0.1
(1)
(2)
0.5
0.5
A
Ω
0.5
µA
1.9
1.7
V
0.8
V
V
°C
°C
1
µA
Thermal shutdown will protect the device from permanent damage.
For the LM3525-L, OFF is EN ≥ 2.4V and ON is EN ≤ 0.8V. For the LM3525-H, OFF is EN ≤ 0.8V and ON is EN ≥ 2.4V
AC 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: VIN = 5.0V.
Symbol
Parameter
Conditions
Min
Typ
Max
Units
tr
OUT Rise Time
RL = 10Ω
200
µs
tf
OUT Fall Time
RL = 10Ω
20
µs
tON
Turn on Delay, EN to OUT
RL = 10Ω
200
µs
tOFF
Turn off Delay, EN to OUT
RL = 10Ω
20
µs
tOC
Over Current Flag Delay
RL = 0
1
ms
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LM3525
SNVS051D – FEBRUARY 2000 – REVISED MARCH 2013
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TYPICAL APPLICATION CIRCUIT
PIN DESCRIPTION
Pin Number
1
Pin Name
Pin Function
EN (LM3525-L) Enable (Input): Logic-compatible enable input.
EN (LM3525-H)
2
FLG
Fault Flag (Output): Active-low, open-drain output. Indicates overcurrent, UVLO and thermal shutdown.
3
GND
Ground
4, 5
NC
Not internally connected.
7
IN
Supply Input: This pin is the input to the power switch and the supply voltage for the IC.
6, 8
OUT
Switch Output: This pin is the output of the high side switch. Pins 6 & 8 must be tied together.
Figure 3. Typical Application Circuit
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SNVS051D – FEBRUARY 2000 – REVISED MARCH 2013
Typical Performance Characteristics
VIN = 5.0V, IL = 500 mA, TA = 25°C unless otherwise specified.
RDSON
vs
VIN
RDSON
vs
Temperature
Figure 4.
Figure 5.
Current Limit
vs
Temperature
Over Current Threshold
vs
Temperature
Figure 6.
Figure 7.
Delay
vs
Temperature
UVLO Threshold
Figure 8.
Figure 9.
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LM3525
SNVS051D – FEBRUARY 2000 – REVISED MARCH 2013
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Typical Performance Characteristics (continued)
VIN = 5.0V, IL = 500 mA, TA = 25°C unless otherwise specified.
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Short Circuit Response
Under Voltage Lock Out (UVLO)
Figure 10.
Figure 11.
Turn-ON/OFF Delay and Rise Time/Fall Time
Short Circuit Current
Figure 12.
Figure 13.
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SNVS051D – FEBRUARY 2000 – REVISED MARCH 2013
FUNCTIONAL DESCRIPTION
The LM3525-H and LM3525-L are high side P-Channel switches with active-high and active-low enable inputs,
respectively. Fault conditions turn off and inhibit turn-on of the output transistor and activate the open-drain error
flag transistor sinking current to the ground.
INPUT AND OUTPUT
IN (Input) is the power supply connection to the control circuitry and the source of the output MOSFET.
OUT (Output) is the drain of the output MOSFET. In a typical application circuit, current flows through the switch
from IN to OUT towards the load.
If VOUT is greater than VIN when the switch is enabled, current will flow from OUT to IN since the MOSFET is
bidirectional.
THERMAL SHUTDOWN
LM3525 is internally protected against excessive power dissipation. In the event of a shorted output or heavy
loads that could elevate the die temperature to above approximately 135°C, the thermal shutdown circuit of the
LM3525 will be activated and the power switch turned off.
The switch is turned on after die temperature drops by 10°C. This built-in temperature hysteresis prevents
undesirable oscillation of the thermal protection circuit and allows the device to reset itself after it is cooled down.
UNDERVOLTAGE LOCKOUT
UVLO prevents the MOSFET switch from turning on until input voltage exceeds 1.9V.
UVLO shuts off the MOSFET switch and signals the fault flag if input voltage drops below 1.8V. UVLO functions
only when device is enabled.
CURRENT LIMIT
The current limit circuit is designed to protect the system supply, the MOSFET switches and the load from
damage caused by excessive currents. The current limit threshold is set internally to allow a minimum of 500 mA
through the MOSFET but limit the maximum current to 1.0A typical.
FAULT FLAG
The fault flag is an open-drain output capable of sinking 10 mA load current to typically 60 mV above ground.
The fault flag is active (pulled low) when any of the following conditions are present: undervoltage, current limit,
or thermal shutdown.
A 1ms delay in reporting fault condition prevents erroneous fault flags and eliminates the need for external RC
delay network.
Application Information
FILTERING
The USB specification indicates that “no less than 120 µF tantalum capacitors” must be used on the output of
each downstream port. This bulk capacitance provides the short-term transient current needed during a hot plugin. Current surges caused by the input capacitance of the down stream device could generate undesirable EMI
signals. Ferrite beads in series with all power and ground lines are recommended to eliminate or significantly
reduce EMI.
In selecting a ferrite bead, the DC resistance of the wire used must be kept to minimum to reduce the voltage
drop.
A 0.01 µF ceramic capacitor is recommended on each port directly between the Vbus and ground pins to prevent
EMI damage to other components during the hot - detachment.
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LM3525
SNVS051D – FEBRUARY 2000 – REVISED MARCH 2013
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Adequate capacitance must be connected to the input of the device to limit the input voltage drop during a hotplug event to less than 330 mV. For a few tens of µs, the host must supply the inrush current to the peripheral,
charging its bulk capacitance to Vbus. This current is initially supplied by the input capacitor. A 33 µF 16V
tantalum capacitor is recommended.
In choosing the capacitors, special attention must be paid to the Effective Series Resistance, ESR, of the
capacitors to minimize the IR drop across the capacitor's ESR.
SOFT START
To eliminate the upstream voltage droop caused by the high in-rush current drawn by the output capacitors, the
inrush current is internally limited to 1.0A.
TRANSIENT OVER-CURRENT DELAY
In USB applications, it is required that output bulk capacitance is utilized to support hot-plug events. During hotplug events, inrush currents may also cause the flag to go active. Since these conditions are not valid overcurrent faults, the USB controller must ignore the flag during these events.
High transient current is also generated when switch is enabled and large values of capacitance at the output
have to be rapidly charged. The inrush currents created could exceed the short circuit current limit threshold of
the device forcing it into the current limit mode. The capacitor is charged with the maximum available short circuit
current set by the LM3525. The duration of the inrush current depends on the size of the output capacitance and
load current. Since this is not a valid fault condition, the LM3525 delays the generation of the fault flag for 1 ms.
If condition persists due to other causes such as a short, a fault flag is generated after a 1 ms delay has elapsed.
The LM3525's 1 ms delay in issuing the fault flag is adequate for most applications. If longer delays are required,
an RC filter as shown in Figure 14 may be used.
Figure 14. Transient Fitter
PCB LAYOUT CONSIDERATIONS
In order to meet the USB requirements for voltage drop, droop and EMI, each component used in this circuit
must be evaluated for its contribution to the circuit performance as shown in Figure 15. The PCB layout rules and
guidelines must be followed.
• Place the switch as close to the USB connector as possible. Keep all Vbus traces as short as possible and use
at least 50-mil, 1 ounce copper for all Vbus traces. Solder plating the traces will reduce the trace resistance.
• Avoid vias as much as possible. If vias are used, use multiple vias in parallel and/or make them as large as
possible.
• Place the output capacitor and ferrite beads as close to the USB connector as possible.
• If ferrite beads are used, use wires with minimum resistance and large solder pads to minimize connection
resistance.
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SNVS051D – FEBRUARY 2000 – REVISED MARCH 2013
Figure 15. Self-Powered Hub Per-Port Voltage Drop
Typical Applications
Figure 16. SIngle-Port USB Self-Powered Hub
Figure 17. Soft-Start Application
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LM3525
SNVS051D – FEBRUARY 2000 – REVISED MARCH 2013
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Figure 18. Inrush Current-limit Application
10
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SNVS051D – FEBRUARY 2000 – REVISED MARCH 2013
REVISION HISTORY
Changes from Revision C (March 2013) to Revision D
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Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 10
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PACKAGE OPTION ADDENDUM
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30-Sep-2021
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
LM3525M-H
ACTIVE
SOIC
D
8
95
Non-RoHS
& Green
Call TI
Level-1-235C-UNLIM
-40 to 125
3525
M-H
LM3525M-H/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
3525
M-H
LM3525M-L
ACTIVE
SOIC
D
8
95
Non-RoHS
& Green
Call TI
Level-1-235C-UNLIM
-40 to 125
3525
M-L
LM3525M-L/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
3525
M-L
LM3525MX-H/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
3525
M-H
LM3525MX-L/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
3525
M-L
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of