MAX1940

Triple USB Switch with Autoreset and Fault Blanking


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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 control logic and independent shutdown controls for each channel provide additional flexibility. An autoreset feature 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 protect the USB port. Built-in thermal-overload protection turns off the switch when the die temperature exceeds +160°C. Accurate internal current-limiting circuitry protects the input supply against both overload and short-circuit conditions. Independent open-drain fault signals (active-low FAULTA, active-low FAULTB, and active-low FAULTC) notify the microprocessor when a thermal-overload, current-limit, undervoltage lockout (UVLO), or short-circuit fault occurs. A 20ms fault-blanking feature enables the circuit 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.
MAX1940: Typical Operating Circuit MAX1940: Typical Operating Circuit Enlarge+

Key Features

  • Triple USB Switch in Tiny 16-Pin QSOP Package
  • Autoreset Feature Saves System Power
  • Guaranteed 500mA Load Current per Channel
  • Built-In 20ms Fault-Blanking Circuitry
  • Active-High/Active-Low Control Logic
  • Fully Compliant to USB Specifications
  • 4V to 5.5V Input Voltage Range
  • Independent Shutdown Control
  • Independent Fault Indicator Outputs
  • Thermal-Overload Protection
  • 3µA Standby Current

Applications/Uses

  • Computers: Desktop, Workstation, Server
  • Docking Stations
  • Notebook Computers
  • PDAs and Palmtop Computers
  • USB Hubs
  • USB Ports

See parametric specs for Current Limit and USB Power Switches (80)


Part NumberUSBPower SwitchesCurrent Limit
(mA)
Current Limit
(mA)
Fault IndicatorCurrent Limit Accuracy
(%)
Current Limit Set ByRON
(Ω)
VSUPPLY
(V)
VSUPPLY
(V)
Oper. Temp.
(°C)
Package/PinsBudgetary
Price
minmaxtypminmaxSee Notes
MAX1940 Yes3700700Yes26Preset0.08545.5-40 to +85
QSOP/16
$1.31 @1k

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
Request Reliability Report for: MAX1940 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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