MAXIM Integrated Products, represented by Arrow Electronics , has introduced the MAX1940 triple current-limited switch with autoreset and fault blanking for universal serial bus (USB) applications.
Its small 16-pin SSOP package makes it suitable for notebook computers, desktop computers, and PDAs.
Each channel is guaranteed to supply 500mA and meets all USB specifications. For applications that require additional supply current for a peripheral device, the MAX1940 can supply a minimum of 700mA.
The MAX1940 provides several safety features to protect the USB port. Built-in thermal protection turns off the switch when the die temperature exceeds 160°C. Accurate internal current-limiting protects the input supply against both overload and short-circuit conditions.
Independent open-drain fault signals 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 autoreset feature automatically restarts the output after the short-circuit or overload condition is removed.
Quiescent current when all switches are enabled is a low 60 microamps and drops to only 3 microamps when the switches are off. Thermal overload protection automatically limits power dissipation and junction temperature to safe levels.
The MAX1940 is screened for the extended-industrial temperature range (-40°C to +85°C).