Hot Swap Controller with IC Compatible Monitoring

The LTC4215/LTC4215-2 Hot Swap™ controllers allow a board to be safely inserted and removed from a live backplane. Using an external N-channel pass transistor, board supply voltage and inrush current are ramped up at an adjustable rate. An I2C interface and onboard ADC allow for monitoring of load current, voltage and fault status.

The device features adjustable foldback current limit and a soft-start pin that sets the dI/dt of the inrush current. An I2C interface may configure the part to latch-off or automatically restart after the LTC4215 detects a current limit fault.

The controller has additional features to interrupt the host when a fault has occurred, notify when output power is good, detect insertion of a load card, and power-up either automatically upon insertion or wait for an I2C command to turn on.

The LTC4215 has a 20μs circuit breaker filter for applications that require a fast fault response time and it defaults to latch-off after an overcurrent fault. The LTC4215-2 has an extended 420μs circuit breaker filter for applications where supply transients may exceed 20μs and it defaults to restart automatically after an overcurrent fault.

Circuit Breaker Timeout

General Purpose Outputs

LTC4215

20μs

1

LTC4215-1

20μs

3

LTC4215-2

420μs

1

LTC4215-3

420μs

3

Applications

* Live Board Insertion

* Electronic Circuit Breakers

* Computers, Servers

* Platform Management

* Allows Safe Insertion into Live Backplane

* 8-Bit ADC Monitors Current and Voltage

* I2C/SMBus Interface

* Wide Operating Voltage Range: 2.9V to 15V

* 20μs (LTC4215) or 420μs (LTC4215-2) Circuit Breaker Timeout

* dI/dt Controlled Soft-Start

* High Side Drive for External N-Channel MOSFET

* No External Gate Capacitor Required

* Input Overvoltage/Undervoltage Protection

* Optional Latch-off or Auto-Retry After Faults

* Alerts Host After Faults

* Inrush Current Limit with Foldback

* Available in 24-Pin (4mm × 5mm) QFN Package

* LTC4215 also available in 16-Lead Narrow SSOP Package