Input Overvoltage Protection Up to +28V Preset Overvoltage Protection Trip Level 6.38V (MAX4919B) 5.80V (MAX4920B) 4.65V (MAX4921B) Adapter/Car-Kit Auto-Selector Low-Current Undervoltage Lockout Mode Internal 1.8A (min) Battery Switchover FET Integrated Low-Battery Detect Battery Short-Circuit Protection Low-Cost External nMOS Overvoltage FET 14-Pin TDFN Package (3mm x 3mm)
- Cell Phones
- Digital Still Cameras
- MP3 Players
- PDAs and Palmtop Devices
The MAX4919B/MAX4920B/MAX4921B overvoltage protection controllers protect low-voltage systems against high-voltage faults up to +28V. An internal 1.8A (min) pFET with low RON (100mΩ) switches a battery to the load and also protects the battery against short-circuit faults. When a short circuit occurs, the current through the internal pFET is limited for a blanking period. If the short condition is present after the blanking period, the switch is latched off and remains off until one of the input signals (IN, HP_PWR, PWR_ON) is cycled. The pFET is turned on by a logic-high voltage at PWR_HOLD, HP_PWR, PWR_ON, or IN.
The overvoltage thresholds (OVLO) are preset to +6.38V (MAX4919B), +5.80V (MAX4920B), and +4.65V (MAX4921B). When the input voltage drops below the undervoltage lockout (UVLO) threshold, the devices enter a low-current standby mode. In shutdown mode, the current is reduced to 0.4µA. The MAX4919B/MAX4920B have a +4.27V UVLO threshold, and the MAX4921B has a +2.35V UVLO threshold.
The MAX4919B/MAX4920B/MAX4921B are offered in a small 14-pin TDFN package (3mm x 3mm) with an exposed paddle and are specified over the extended -40°C to +85°C temperature range.