MAXIM MAX1922 User Manual
MAX1922
1A Current-Limited Switch for 2 USB Ports
________________________________________________________________
Maxim Integrated Products
1
Typical Operating Circuit
19-2254; Rev 3; 4/09
Pin Configurations
Ordering Information
General Description
The MAX1922 current-limited 70mΩ switch with built-in
fault blanking provides an accurate, preset 1.4A to 2.1A
current limit, making it ideal for dual USB applications.
Its low quiescent supply current (16µA) and standby
current (1µA) conserve battery power in portable applications. The MAX1922 operates with inputs from 2.7V
to 5.5V, making it ideal for both 3V and 5V systems.
An overcurrent signal (OC) notifies the microprocessor
that the internal current limit has been reached. A 10ms
overcurrent-blanking feature allows momentary faults
(such as those caused when hot-swapping into a
capacitive load) to be ignored, thus preventing false
alarms to the host system. This blanking also prevents
an OC signal from being issued when the device is
powering up.
The MAX1922 has several safety features to ensure that
the USB port is protected. Built-in thermal-overload protection limits power dissipation and junction temperature. The device also has accurate internal currentlimiting circuitry to protect the input supply against
overload.
The MAX1922 is offered in a space-saving 8-pin SO
package and a 10-pin TDFN package and operates over
the extended (-40°C to +85°C) temperature range.
Applications
Notebook Computers
USB Ports
USB Hubs
Docking Stations
Features
o Accurate Current Limit (1.4A min, 2.1A max)
o 10ms Internal OC Blanking Timeout
o OC Blanking During Power-Up
o 125mΩ (max) High-Side MOSFET
o Short-Circuit and Thermal Protection with
Overcurrent Logic Output
o Undervoltage Lockout
o 16µA Quiescent Supply Current
o 1µA (max) Standby Supply Current
o 2.7V to 5.5V Supply Range
o UL Recognized: UL# E211395
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
*
EP = Exposed paddle.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
Pin Configurations continued at end of data sheet.
PART TEMP RANGE
MAX1922ESA+ -40°C to +85°C 8 SO
MAX1922ETB+ -40°C to +85°C 10 TDFN-EP* AQQ
PINPACKAGE
MARK
TOP
—
TOP VIEW
1
GND
2
MAX1922
3
IN
EN
4
SO
87OUT
OUTIN
OUT
6
OC
5
INPUT
2.7V TO 5.5V
OFF
ON
IN OUTPUTOUT
MAX1922
OC
EN
GND
MAX1922
1A Current-Limited Switch for 2 USB Ports
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN= 5V, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
IN, EN, OC to GND...................................................-0.3V to +6V
OUT to GND ................................................-0.3V to (V
IN
+ 0.3V)
Maximum Switch Current.........................2.3A (internally limited)
OUT Short-Circuit to GND ..........................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 5.88mW/°C above +70°C)................471mW
10-Pin TDFN (derate 18.5mW/°C above +70°C) .......1481mW
Operating Temperature Range (extended).........-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
)
OPERATING CONDITION
Input Voltage V
POWER SWITCH
Switch Static Drain-Source OnState Resistance
Switch Turn-On Time t
Switch Turn-Off Time t
ENABLE INPUT (EN)
EN High-Level Input Voltage V
EN Low-Level Input Voltage V
EN Input Current VEN = VIN or GND -1 1 µA
Startup Time
CURRENT LIMIT
Overload Output Current I
Short-Circuit Output Current I
SUPPLY CURRENT
Supply Current, Low-Level Input VEN = VIN = V
Supply Current, High-Level
Input
Supply-Leakage Current
UNDERVOLTAGE LOCKOUT
Undervoltage Lockout UVLO Rising edge, 100mV hysteresis 2.0 2.4 2.6 V
OVERCURRENT (OC)
OC Threshold 1.1 A
OC Output Low Voltage V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
IN
TA = +25°C VIN = 4.4V to 5.5V 70 100
R
DS(ON
LIMIT
ON
OFF
IH
IL
SC
I
Q
OL
TA = 0°C to +85°C
I
= 400mA 80 200 µs
LOAD
I
= 400mA 3 6 20 µs
LOAD
VIN = 2.7V to 3.6V 2.0
VIN = 3.7V to 5.5V 2.4
VIN = 2.7V to 5.5V 0.8 V
V
= 5V, C
IN
to 50% full V
Force V
= 150µF from EN driven low
OUT
OUT
to 4.5V 1.4 1.75 2.1 A
OUT
OUT shorted to GND 1 1.4 A
OUT
VEN = 0, I
V
= VIN = 5.5V,
EN
V
= 0
OUT
I
= 1mA, VIN = 3V 0.4 V
SINK
OUT
= 0
VIN = 4.4V to 5.5V 125
V
= 3V 72 150
IN
= 5.5V 0.002 1 µA
Timer not running 16 25
Timer running 35
TA = +25°C 0.01 2
T
= 0°C to +85°C 15
A
2.7 5.5 V
1ms
mΩ
V
µA
µA
MAX1922
1A Current-Limited Switch for 2 USB Ports
_______________________________________________________________________________________ 3
Note 1: Specifications to -40°C are guaranteed by design, not production tested.
ELECTRICAL CHARACTERISTICS
(VIN= 5V, TA= -40°C to +85°C, unless otherwise noted.) (Note 1)
ELECTRICAL CHARACTERISTICS (continued)
(VIN= 5V, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
)
OC Off-State Current VIN = VOC = 5V 1 µA
OC Blanking Timeout Period t
THERMAL SHUTDOWN
Thermal Shutdown Threshold 165 °C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
BL
From overcurrent condition to OC assertion 6 10 13 ms
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
OPERATING CONDITION
Input Voltage V
POWER SWITCH
Switch Static Drain-Source
On-State Resistance
Switch Turn-On Time t
Switch Turn-Off Time t
ENABLE INPUT (EN)
EN High-Level Input Voltage V
EN Low-Level Input Voltage V
EN Input Current VEN = VIN or GND -1 1 µA
CURRENT LIMIT
Overload Output Current I
Short-Circuit Output Current I
SUPPLY CURRENT
Supply Current, Low-Level Input VEN = VIN = V
Supply Current, High-Level
Input
Supply Leakage Current VEN = VIN = 5.5V, V
UNDERVOLTAGE LOCKOUT
Undervoltage Lockout UVLO Rising edge, 100mV hysteresis 2.0 2.9 V
OVERCURRENT (OC)
OC Threshold 1.1 A
OC Output Low Voltage V
OC Off-State Current VIN = VOC = 5V 1 µA
OC Blanking Timeout Period t
R
DS(ON
LIMIT
IN
ON
OFF
IH
IL
SC
I
Q
OL
BL
VIN = 4.4V to 5.5V 125
VIN = 3V 150
I
= 400mA 200 µs
LOAD
I
= 400mA 1 20 µs
LOAD
VIN = 3.0V to 3.6V 2.0
VIN = 3.7V to 5.5V 2.4
VIN = 3.0V to 5.5V 0.8 V
Force V
OUT shorted to GND 1.5 A
VEN = GND, I
I
SINK
From overcurrent condition to OC assertion 6 14 ms
to 4.5V 1.2 2.3 A
OUT
= 5.5V 2 µA
OUT
= 0, timer not running 25 µA
OUT
= GND 15 µA
OUT
= 1mA, VIN = 3V 0.4 V
3.0 5.5 V
mΩ
V
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