MAX1940_10 Datasheet, PDF (1/13 Pages) Maxim Integrated Products – Triple USB Switch with Autoreset and Fault Blanking

19-2497; Rev 1; 2/10
Triple USB Switch with Autoreset and
Fault Blanking
General Description
The MAX1940 triple current-limited switch with auto-
reset supplies a guaranteed 500mA load per channel in
accordance with USB specifications. The MAX1940
operates from a 4V to 5.5V input supply and consumes
only 60µA of quiescent current when operating and only
3µA in standby. Selectable active-high/active-low con-
trol logic and independent shutdown controls for each
channel provide additional flexibility. An autoreset fea-
ture latches the switch off in the event of a short circuit,
saving system power. The switch reactivates upon
removal of the shorted condition.
The MAX1940 provides several safety features to pro-
tect the USB port. Built-in thermal-overload protection
turns off the switch when the die temperature exceeds
+160°C. Accurate internal current-limiting circuitry pro-
tects the input supply against both overload and short-
circuit conditions. Independent open-drain fault signals
(FAULTA, FAULTB, and FAULTC) notify the micro-
processor when a thermal-overload, current-limit,
undervoltage lockout (UVLO), or short-circuit fault
occurs. A 20ms fault-blanking feature enables the cir-
cuit to ignore momentary faults, such as those caused
when hot-swapping a capacitive load, preventing false
alarms to the host system. The fault-blanking feature
also prevents fault signals from being issued when the
device powers up the load.
The MAX1940 is available in a space-saving 16-pin
QSOP package and operates over the extended (-40°C
to +85°C) temperature range.
Applications
USB Ports
USB Hubs
Notebook Computers
PDAs and Palmtop
Computers
Docking Stations
Desktop Computers
Pin Configuration
TOP VIEW
ONA ₁
IN1 2
IN2 3
IN3 4
ONB 5
IN4 6
IN5 7
ONC 8
MAX1940
QSOP
16 FAULTA
15 OUTA
14 GND
13 OUTB
12 FAULTB
11 SEL
10 OUTC
9 FAULTC
Features
o Triple USB Switch in Tiny 16-Pin QSOP Package
o Autoreset Feature Saves System Power
o Guaranteed 500mA Load Current per Channel
o Built-In 20ms Fault-Blanking Circuitry
o Active-High/Active-Low Control Logic
o Fully Compliant to USB Specifications
o 4V to 5.5V Input Voltage Range
o Independent Shutdown Control
o Independent Fault Indicator Outputs
o Thermal-Overload Protection
o 3µA Standby Current
PART
MAX1940EEE
Ordering Information
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
16 QSOP
Typical Operating Circuit
INPUT
4V TO 5.5V
ACTIVE-HIGH/ACTIVE-LOW
SELECTABLE
MAX1940
IN1
FAULTA
IN2
FAULTB
IN3
FAULTC
IN4
IN5
OUTA
ONA
ONB
OUTB
ONC
SEL
OUTC
GND
USB
PORT A
USB
PORT B
USB
PORT C
________________________________________________________________ Maxim Integrated Products 1
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or visit Maxim’s website at www.maxim-ic.com.