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.
title | Download file |
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MAX1940 Data Sheet | MAX1940.pdf |
Part Number | USB | Power Switches | Current Limit (mA) | Current Limit (mA) | Fault Indicator | Current Limit Accuracy (%) | Current Limit Set By | RON (Ω) | VSUPPLY (V) | VSUPPLY (V) | Oper. Temp. (°C) | Package/Pins | Budgetary Price |
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min | max | typ | min | max | See Notes | ||||||||
MAX1940 | Yes | 3 | 700 | 700 | Yes | 26 | Preset | 0.085 | 4 | 5.5 | -40 to +85 | QSOP/16 | $1.25 @1k |
Part Number | Status | Recommended Replacement | Package | Temp | RoHS |
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MAX1940EEE | No Longer Available | MAX1940EEE+ | QSOP,;16 pin;30.9 mm² | -40°C to +85°C | No |
MAX1940EEE+ | Active | QSOP,;16 pin;30.9 mm² | -40°C to +85°C | Lead Free | |
MAX1940EEE+T | No Longer Available | QSOP;16 pin | -40°C to +85°C | See data sheet | |
MAX1940EEE-T | No Longer Available | QSOP;16 pin | -40°C to +85°C | See data sheet |