MAX4946: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
MAX4943, MAX4944, MAX4944L, MAX4945, MAX4946, MAX4949: Typical Operating Circuit
Applications/Uses
  • Cell Phones
  • Digital Still Cameras
  • MP3 Players
  • PDAs and Palmtop Devices
DataSheet
titleDownload file
MAX4943-MAX4949 Data SheetMAX4943-MAX4949.pdf
Parametrics
Part NumberChannelsVIN
(V)
VIN
(V)
Over Voltage Trip Level
(V)
Under Voltage Lockout
(V)
Over Volt. FlagtGATE (On)
(ms)
tGATE (Off)
(µs)
Package/PinsBudgetary
Price
minmaxSee Notes
MAX494412.2286.354.15Open-Drain30.22µDFN/8$2.75 @1k
MAX49455.84.15µDFN/8$2.76 @1k
MAX49464.562.45µDFN/8-
MAX49498.92.45µDFN/8-
Quality and Environmental Data
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
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX4946ELA+ActiveµDFN,;8 pin;4.2 mm²-40°C to +85°CLead Free
MAX4946ELA+TActiveµDFN,;8 pin;4.2 mm²-40°C to +85°CLead Free
MAX4943-MAX4949.pdf MAX4949
MAX4943-MAX4949_cn.pdf MAX4949
MAX4946.pdf MAX4946
MAX4943-MAX4949_cn.pdf MAX4943