MAX5921:-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current

The MAX5921/MAX5939 hot-swap controllers allow a circuit card to be safely hot plugged into a live backplane. The MAX5921/MAX5939 operate from -20V to -80V and are well suited for -48V power systems. These devices are pin compatible with both the LT1640 and LT4250 and provide improved features over these devices. The MAX5921/MAX5939 provide a controlled turn-on to circuit cards preventing damage to board connectors, board components, and preventing glitches on the power-supply rail. The MAX5921/MAX5939 provide undervoltage, overvoltage, and overcurrent protection. These devices ensure that the input voltage is stable and within tolerance before applying power to the load. Both the MAX5921 and MAX5939 protect a system against overcurrent and short-circuit conditions by turning off the external MOSFET in the event of a fault condition. The MAX5921/MAX5939 protect against input voltage steps by limiting the load current to a safe level without turning off power to the load. The device features an open-drain power-good status output, active-low PWRGD or PWRGD for enabling downstream converters (see Selector Guide). A built-in thermal shutdown feature is also included to protect the external MOSFET in case of overheating. The MAX5939 features a latched fault output. The MAX5921 contains built-in autoretry circuitry after a fault condition. The MAX5921/MAX5939 are available in an 8-pin SO package and operate in the extended -40°C to +85°C temperature range.

Key Features
  • Allows Safe Board Insertion and Removal from a Live -48V Backplane
  • Pin-Compatible with LT1640 and LT4250
  • Circuit Breaker Immunity to Input Voltage Steps and Current Spikes
  • 450mA GATE Pulldown Current During Short-Circuit Condition
  • Exponential GATE Pulldown Current
  • Withstands -100V Input Transients with No External Components
  • Programmable Inrush and Short-Circuit Current Limits
  • Operates from -20V to -80V
  • Programmable Overvoltage Protection
  • Programmable Undervoltage Lockout with Built-In Glitch Filter
  • Overcurrent Fault Integrator
  • Powers Up into a Shorted Load
  • Power-Good Control Output
  • Thermal Shutdown Protects External MOSFET
MAX5921, MAX5939: Typical Operating Circuit
MAX5921, MAX5939: Typical Operating Circuit
Applications/Uses
  • Base-Station Line Cards
  • Central-Office Line Cards
  • Network Routers and Switches
  • Server Line Cards
  • Telecom Line Cards
DataSheet
titleDownload file
MAX5921-MAX5939 Data SheetMAX5921-MAX5939.pdf
Parametrics
Part NumberVIN
(V)
VIN
(V)
Circuit Breaker/ Current LimitCircuit Breaker/Current Limit Threshold
(mV)
Fault Condition ControlChannelsPositive/Negative RailFeaturesPackage/PinsBudgetary
Price
minmaxSee Notes
MAX5921-20-80Current Limit50Periodic Retry1NegativeUndervoltage/Overvoltage ProtectionSOIC(N)/8$2.53 @1k
MAX5939Latched Off-SOIC(N)/8$2.93 @1k
Design kits & evaluation modules
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX5921AESANo Longer AvailableMAX5921AESA+SOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
MAX5921AESA+ActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
MAX5921AESA+TActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
MAX5921AESA-TNo Longer AvailableMAX5921AESA+TN.SO;8 pin-40°C to +85°CSee data sheet
MAX5921BESANo Longer AvailableMAX5921BESA+SOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
MAX5921BESA+ActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
MAX5921BESA+TActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
MAX5921BESA-TNo Longer AvailableMAX5921BESA+TN.SO;8 pin-40°C to +85°CSee data sheet
MAX5921CESANo Longer AvailableSOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
MAX5921CESA-TNo Longer AvailableN.SO;-40°C to +85°CSee data sheet
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX5921DESANo Longer AvailableSOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
MAX5921DESA-TNo Longer AvailableN.SO;8 pin-40°C to +85°CSee data sheet
MAX5921EESANo Longer AvailableMAX5921EESA+SOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
MAX5921EESA+ActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
MAX5921EESA+TActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
MAX5921EESA-TNo Longer AvailableMAX5921EESA+TN.SO;8 pin-40°C to +85°CSee data sheet
MAX5921FESANo Longer AvailableMAX5921FESA+SOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
MAX5921FESA+ActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
MAX5921FESA+TActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
MAX5921FESA-TNo Longer AvailableMAX5921FESA+TN.SO;8 pin-40°C to +85°CSee data sheet
MAX5921-MAX5939.pdf MAX5939
MAX5921-MAX5939_cn.pdf MAX5939
MAX5921-MAX5939_cn.pdf MAX5939