MAX4945 Overvoltage-Protection Controllers with Internal FET
Product Details
The MAX4943–MAX4946/MAX4949 family of overvoltage-protection devices feature a low 80mΩ (typ) RON internal FET and protect low-voltage systems against voltage faults up to +28V. These devices also drive an optional external pFET to protect down to -28V when connected to a load with reverse current protection. When the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected components.
All switches feature a minimum 1.2A current-limit protection. During a short-circuit occurrence, the MAX4944B and MAX4945B place the switch in a latchoff state where the switch turns off and remains off. For the autoretry devices, the switch turns off and continuously checks after a 15ms (typ) retry time.
The overvoltage thresholds (OVLO) are preset to 7.4V, 6.35V, 5.8V, 4.56V, or 8.9V. The undervoltage-lockout (UVLO) thresholds are preset to 2.45V and 4.15V. When the input voltage drops below the undervoltagelockout (UVLO) threshold, the devices enter a lowcurrent standby mode. (See the Ordering Information/Selector Guide in the full data sheet for more details on UVLO/OVLO).
All devices are offered in a small, 8-pin µDFN (2mm x 2mm) package and are specified for operation over the -40°C to +85°C temperature range.
Applications
- Cell Phones
- Digital Still Cameras
- MP3 Players
- PDAs and Palmtop Devices
Features and Benefits
- Input Voltage Protection Up to +28V
- Integrated nFET Switch
- Preset Overvoltage Protection Trip Level
- 7.40V (MAX4943)
- 6.35V (MAX4944_)
- 5.80V (MAX4945_)
- 4.56V (MAX4946)
- 8.90V (MAX4949)
- Low-Current Undervoltage-Lockout Mode
- Short-Circuit Protection (Latchoff/Autoretry)
- Internal 15ms (typ) Startup Delay and Retry Times
- Input Voltage Power-Good Logic Output
- Thermal-Shutdown Protection
- Small, 8-Pin (2mm x 2mm) µDFN Package