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MAX5949A, MAX5949B

-48V Hot-Swap Controllers with External RSENSE

Product Details

Key Features

Parametric specs for Hot Swap Controllers
VIN (V) (min) -20
VIN (V) (max) -80
# Channels 1
Circuit Breaker/ Current Limit Current Limit
Circuit Breaker/Current Limit Threshold (mV) 50
Fault Condition Control Latched Off
Positive/Negative Rail Negative
Features Pin-and-Function Compatible with LT4250
Package/Pins SOIC (N)/8
Budgetary
Price (See Notes)
2.82
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Simplified Block Diagram

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Parameters

Parametric specs for Hot Swap Controllers
VIN (V) (min) -20
VIN (V) (max) -80
# Channels 1
Circuit Breaker/ Current Limit Current Limit
Circuit Breaker/Current Limit Threshold (mV) 50
Fault Condition Control Latched Off
Positive/Negative Rail Negative
Features Pin-and-Function Compatible with LT4250
Package/Pins SOIC (N)/8
Budgetary
Price (See Notes)
2.82

Key Features

  • Allow Safe Board Insertion and Removal from a Live -48V Backplane
  • Pin and Function Compatible with LT4250L (MAX5949A)
  • Pin Compatible with LT1640L (MAX5949A)
  • Pin and Function Compatible with LT4250H (MAX5949B)
  • Pin Compatible with LT1640H (MAX5949B)
  • Circuit-Breaker Immunity to Input Voltage Steps and Current Spikes
  • Withstand -100V Input Transients with No External Components
  • Programmable Inrush and Short-Circuit Current Limits
  • Operate from -20V to -80V
  • Programmable Overvoltage Protection
  • Programmable Undervoltage Lockout
  • Power Up into a Shorted Load
  • Power-Good Control Output

Applications/Uses

  • -48V Distributed Power Systems
  • Base-Station Line Cards
  • Central-Office Line Cards
  • Central-Office Switching
  • Negative Power-Supply Controls
  • Network Routers and Switches
  • Server Line Cards
  • Telecom Line Cards

Description

The MAX5949A/MAX5949B are hot-swap controllers that allow a circuit card to be safely hot plugged into a live backplane. The MAX5949A/MAX5949B operate from -20V to -80V and are well-suited for -48V power systems. These devices are pin and function compatible with the LT4250 and pin compatible with the LT1640.

The MAX5949A/MAX5949B provide a controlled turn-on to circuit cards preventing glitches on the power-supply rail and damage to board connectors and components. The MAX5949A/MAX5949B provide undervoltage, overvoltage, and overcurrent protection. These devices ensure the input voltage is stable and within tolerance before applying power to the load.

Both the MAX5949A and MAX5949B protect a system against overcurrent and short-circuit conditions by turning off the external MOSFET in the event of a fault condition. The MAX5949A/MAX5949B also provide protection against input voltage steps. During an input voltage step, the MAX5949A/MAX5949B limit the current drawn by the load to a safe level without turning off power to the load.

Both devices feature an open-drain power-good status output (PWRGD-bar for the MAX5949A or PWRGD for the MAX5949B) that can be used to enable downstream converters.

The MAX5949A/MAX5949B are available in an 8-pin SO package. Both devices are specified for the extended -40°C to +85°C temperature range.

Simplified Block Diagram

MAX5949A, MAX5949B: Typical Operating Circuit MAX5949A, MAX5949B: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .