MAX1940 is a triple current-limited switch with auto-reset that 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 r
The MAX1940 is a triple current‑limited USB power switch that operates from a 4 V to 5.5 V supply and provides a guaranteed 500 mA load per channel. It features independent enable inputs, fault indicator outputs, an autoreset function, and a 20 ms fault‑blanking circuit to protect against short‑circuit and overload conditions.
The device is supplied in a 16‑pin QSOP package and is rated for an operating temperature range of –40 °C to +85 °C. Electrical specifications include a typical on‑resistance of 135 mΩ per switch, standby supply current of 10 µA with all switches disabled, and built‑in thermal‑overload protection that shuts off the switch at +160 °C.
| Supply Voltage Range | 4.0 V – 5.5 V |
|---|---|
| Continuous Load Current per Channel | 500 mA |
| Switch On‑Resistance (typical) | 135 mΩ |
| Standby Supply Current (all switches disabled) | 10 µA |
| Operating Temperature Range | -40 °C to +85 °C |
Each channel can supply up to 500 mA continuously.
The standby supply current is 10 µA with all switches disabled.
It operates from –40 °C to +85 °C.