EC9521|USB Power-Distribution Switches


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EC9521

​​  ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​​​ USB Power-Distribution Switches

 

 

General Description

The​​ EC9521 power switches are designed for USB applications. The 25mΩN-channel MOSFET power switch

satisfies the voltage drop requirements of USB specification. The protection features include current-limit protection,

short-circuit protection, and over-temperature protection. The device limits the output current at​​ current limit

threshold level. The over-temperature​​ protection limits​​ the junction temperature below 140℃in case of short​​ circuit

or over load conditions. An enable input to enable or disable the device.

 

Features

25mΩ  ​​ ​​​​ High Side MOSFET​​ 

Voltage Range: 3.5V to 5.5V​​ 

Current-Limit and Short-Circuit Protections​​ 

Over-Temperature Protection​​ 

Iset Input​​ 

Enable Input​​ 

Lead Free and Green Devices Available

 

Applications

Notebook and Desktop Computers​​ 

USB Ports​​ 

High-Side Power Protection Switches

 

Pin Configurations

 

 

 

 

 

SOT23-5(Top View) Pin Configuration of​​ EC9521

 

Ordering/Marking​​ Information

 

EC9521​​ ​​ XX ​​​​ X ​​​​ X

 

 ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​​​  ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​​​ RTape & Reel

Package Type ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​​​ ​​ FPb Free

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Device

Marking

Package

Information

EC9521B2XR

EC9521

LLLL

SOT23-5

LLLLLot No

 

 

 

 

 

 

 

 

 

 

 

Pin Function Description

Pin Number

Pin Name

Description

1

VOUT

Output Voltage Pin. The output voltage follows the input voltage. When ENB is 

high or EN is low, the output voltage is discharged by an internal resistor. 

2

GND

Ground. 

3

ISET

i set pin. ILim=120k*1.14V/Riset 

4

EN

Enable Input. Pulling this pin to high will enable the device and pulling this pin 

to low will disable device. The EN pin cannot be left floating. 

5

 

VIN

Power Supply Input. Connect this pin to external DC supply. 

 

Functional Block Diagram

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Absolute Maximum Ratings

Symbol

Parameter

Rating

Unit

VIN

VIN Input Voltage (VIN to GND) 

0.3 to 7

V

VOUT

VOUT to GND Voltage 

0.3 to 7

V

VEN

EN to GND Voltage 

0.3 to 7

V

VISET

ISET to GND Voltage 

0.3 to 7

V

TJ

Maximum Junction Temperature 

150

oC

TSTG

Storage Temperature Range 

65 to +150

oC

TSDR

Maximum Soldering Temperature Range, 10 seconds 

260

oC

Note 1:

Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Exposure to

absolute maximum rating conditions for extended periods may affect device reliability.

 

 

 

 

 

 

Recommended​​ Operating​​ Conditions

Symbol

Parameter

Rating

Unit

VIN

VIN Input Voltage (VIN to GND) 

3.5 to 5.5

V

IOUT

Output current 

0 to 3

A

TA

Ambient Temperature 

40 to 85

oC

TJ

Junction Temperature 

40 to +125

oC

θJA

JunctiontoAmbient Resistance in Free Air 

235

oC/W

 

Typical Application Circuit

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Electrical Characteristics​​ 

Unless otherwise specified, these specifications apply over VIN=5V, VEN =5V and TA=​​ 40 ~ 85​​ . Typical values are at TA=25

Symbol

Parameter

Test Conditions

Min.

Typ.

Max.

Unit

SUPPLY CURRENT

 

VIN Supply Current

No load, VEN=0V

1

μA

No load, VEN=5V

120

150

μA

 

Leakage Current

VOUT=GND, VEN=0V

1

μA

 

Reverse Leakage Current

VIN=GND, VOUT=5V, VEN=0V

1

μA

POWER SWITCH 

RDS(ON)

Power Switch On Resistance

IOUT=1A, TA= 25

25

36

mΩ

UNDERVOLTAGE LOCKOUT (UVLO) 

 

VIN UVLO Threshold Voltage

VIN rising, TA= 40 ~ 85  

3.5

V

 

VIN UVLO Hysteresis

 

0.2

V

CURRENTLIMIT AND SHORTCIRCUIT PROTECTIONS 

ILIM

Current Limit Threshold

iset

1.1

3.9

A

Iset(Riset=51k)

2.4

2.6

2.9

A

ISHORT

Short-Circuit​​ Output​​ Current

 

80%

95%

EN INPUT PIN 

VIH

Input Logic High

VIN=3.6V to 5V

2

V

VL

Input Logic Low

VIN=3.6V to 5V

0.8

V

 

Input Current

 

1

μA

 

VOUT Discharge Resistance

VEN=0V, VOUT=1V

40

Ω

tD(ON)

Turn On Delay Time

 

30

μS

tD(OFF)

Turn Off Delay Time

 

30

μS

tSS

SoftStart Time

No load, COUT=1μF, VIN=5V

400

μS

OVERTEMPERATURE PROTECTION (OTP) 

TOTP

Over-Temperature​​ Threshold

TJ rising

140

 

Over-Temperature​​ Hysteresis

 

20

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Typical Operating Characteristics

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Typical Operating Characteristics(Cont.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Function Description

VIN Under-Voltage Lockout (UVLO)

The​​ EC9521power switches have a built-in under-voltage lockout​​ circuit to​​ keep the output shutting off until internal circuitry is

operating properly. The UVLO circuit has hysteresis and a de-glitch​​ feature so that it will typically ignore undershoot transients

on the​​ input. When input voltage exceeds the UVLO threshold, the output​​ voltage starts a soft-start to reduce the inrush current.​​ 

 

Power Switch

The power switch is an N-channel MOSFET with a low RDS​​ (ON). The​​ internal power MOSFET does not have the body diode.

When IC is off, the MOSFET prevents a current flowing from the VOUT back to VIN and​​ ​​ VIN to VOUT.

 

Current-Limit Protection​​ 

The​​ EC9521power switches provide the current-​​ limit protection function. During current-limit, the devices limit output current

at current limit threshold. For reliable operation, the device should not be operated in current-limit for extended period.

 

Short-Circuit Protection​​ 

When the output voltage drops below 1.5V, which is caused by an over-load or a short-circuit, the devices limit the output

current down to a safe level. The short-circuit current limit is used to reduce the​​ power dissipation during short-circuit​​ 

conditions. If the junction temperature reaches over-temperature threshold, the device will enter the thermal shutdown.

 

ISET​​ 

ISET pin can set the current limit by Riset:​​ ​​ ILim​​ =120k*1.14V/Riset

 

Enable/Disable​​ 

Pull the EN below 0.8V will disable the device, and pull EN above 2V will​​ enable ​​ the ​​ device. When the IC is disabled, the

supply ​​ current ​​ is​​ ​​ reduced to less than 1μA. The enable input is compatible with both TTL and CMOS logic levels. The EN pin

cannot be left floating.

 

Over-Temperature Protection

When ​​ the ​​ junction ​​ temperature ​​ exceeds ​​ 140℃, ​​ the ​​ internal ​​ thermal​​ sense ​​ circuit ​​ turns ​​ off ​​ the ​​ power ​​ FET ​​ and ​​ allows

the device to cool​​ down. ​​ When ​​ the ​​ device’s ​​ junction ​​ temperature ​​ cools ​​ by ​​ 20℃, ​​ the​​ internal ​​ thermal ​​ sense ​​ circuit ​​ will

enable ​​ the ​​ device, ​​ resulting ​​ in ​​ a​​ pulsed ​​ output ​​ during ​​ continuous ​​ thermal ​​ protection. ​​ Thermal​​ protection is designed ​​ to

protect the IC in the event of over​​ ​​ temperature conditions. For ​​ normal ​​ operation, ​​ the ​​ junction​​ temperature cannot exceed

TJ=+125℃.

 

Application Information

Input Capacitor​​ 

A ​​ 1μF ​​ ceramic ​​ bypass ​​ capacitor ​​​​ from ​​ VIN ​​ to ​​ GND, ​​ located​​ ​​ near ​​ the ​​ EC9521, ​​ is ​​ strongly ​​ recommended ​​ to ​​ suppress

the ringing during short circuit fault ​​ event. Without ​​ the ​​ bypass capacitor, the output short may cause sufficient ringing on the

input ​​ (from ​​ supply ​​ lead ​​ inductance) ​​ to ​​ damage ​​ internal​​ ​​ control circuitry.

 

Output Capacitor​​ 

A low-ESR 10μF aluminum electrolytic or tantalum between​​ VOUT and GND is strongly recommended to reduce the​​ voltage

drop during hot-attachment of downstream peripheral. (Per USB 2.0, output ports must have a minimum 120μF of​​ ​​ low-ESR

bulk capacitance per hub). Higher-value output capacitor is better when the output load is heavy. ​​ Additionally,​​ bypassing ​​ the

output ​​ with ​​ a ​​ 0.1μF ceramic ​​ capacitor ​​ improves ​​ the ​​ immunity ​​ of ​​ the ​​ device ​​ to short-circuit transients.

 

Layout Consideration 

The PCB layout should be carefully performed to maximize thermal dissipation and to minimize voltage drop, droop and EMI. 

The following guidelines must be considered: 

1. Please place the input capacitors near the VIN pin as close as possible. 

2. Output decoupling capacitors for load must be placed near the load as close as possible for decoupling high frequency 

ripples. 

3. Locate EC9521and output capacitors near the load to reduce parasitic resistance and inductance for excellent load transient

performance. 

4. The negative pins of the input and output capacitors and the GND pin must be connected to the ground plane of the load. 

5. Keep VIN and VOUT traces as wide and short as possible. 

 

 

 

 

Package Information

SOT23-5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Symbol

SOT23-5

MILLMETER

INCHES

MIN.

MAX.

MIN.

MAX.

A

 

1.45

 

0.057

A1

0.00

0.15

0.000

0.006

A2

0.90

1.30

0.035

0.051

b

0.30

0.50

0.012

0.020

c

0.08

0.22

0.003

0.009

D

2.70

3.10

0.106

0.122

E

2.60

3.00

0.102

0.118

E1

1.40

1.80

0.055

0.071

e

0.95BSC

0.037BSC

e1

1.90BSC

0.075BSC

L

0.30

0.60

0.012

0.024

θ

 

 

 

 

 

 

 

 


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