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MAX4949：Overvoltage-Protection Controllers with Internal FET

Provide Input Voltage Protection Up to +28V without Requiring an External nFET

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.

Key Features 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

MAX4943, MAX4944, MAX4944L, MAX4945, MAX4946, MAX4949: Typical Operating Circuit Applications/Uses Cell Phones Digital Still Cameras MP3 Players PDAs and Palmtop Devices

DataSheet

Parametrics

Quality and Environmental Data

• MAX4949.pdf

Related Products

• MAX4846：Overvoltage Protection Controllers with Low Standby Current
• MAX4844：Overvoltage Protection Controllers with Low Standby Current
• MAX4845：Overvoltage Protection Controllers with Low Standby Current
• MAX4843：Overvoltage Protection Controllers with Low Standby Current

Ordering Information