MAX1940:Triple USB Switch with Autoreset and Fault Blanking

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.

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
MAX1940: Typical Operating Circuit
MAX1940: Typical Operating Circuit
Applications/Uses
  • Computers: Desktop, Workstation, Server
  • Docking Stations
  • Notebook Computers
  • PDAs and Palmtop Computers
  • USB Hubs
  • USB Ports
DataSheet
titleDownload file
MAX1940 Data SheetMAX1940.pdf
Parametrics
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
MAX1940Yes3700700Yes26Preset0.08545.5-40 to +85QSOP/16$1.25 @1k
Related Products
  • MAX1823:Dual USB Switch with Fault Blanking and Autoreset
  • MAX1812:Dual USB Switch with Fault Blanking
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX1940EEENo Longer AvailableMAX1940EEE+QSOP,;16 pin;30.9 mm²-40°C to +85°CNo
MAX1940EEE+ActiveQSOP,;16 pin;30.9 mm²-40°C to +85°CLead Free
MAX1940EEE+TNo Longer AvailableQSOP;16 pin-40°C to +85°CSee data sheet
MAX1940EEE-TNo Longer AvailableQSOP;16 pin-40°C to +85°CSee data sheet
MAX1940.pdf MAX1940
MAX1940.pdf MAX1940