LT4220

Features:

Hot SwapTM Controller for Positive and Negative Supplies
Supply Tracking Mode
±2.7V to ±16.5V Operation
Analog Current Limit with Foldback
Allows Safe Board Insertion and Removal from a Live Backplane
Open-Collector Power Good Comparators
Automatic Retry or Latchoff After a Current Fault
Dual Undervoltage Lockout Comparator Inputs
Current Fault Indication


Application

Live Board Insertion
RAID Systems
5.2V ECL Supplies
Industrial Controls
Split Supply Systems


Pinout




Specifications

VCC to GND ............................................................. 22V
VEE to GND ........................................................... 22V
TRACK, TIMER ..............................  0.3V to VCC + 0.3V
ON+, FB+ ................................. VEE  0.3V to VCC + 0.3V
ON, FB .................................. VEE  0.3V to VCC + 0.3V
GATE+ ................................................ 0.3V to VCC + 8V
GATE .............................. 16.5V with VEE = 22V to 0V
SENSE+ ............................................. 0.3V to VCC + 5V
SENSE, SENSEK ....................... VEE  0.3V to VEE + 3V
PWRGD, FAULT ................................. 0.3V to VCC + 5V
Operating Temperature Range
LT4220C ........................................... 0°C £ TA £ 70°C
LT4220I ....................................... 40°C £ TA £ 85°C
Storage Temperature Range ................. 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C

Description

The LT®4220 16-pin dual voltage Hot Swap controller allows a board to be safely inserted and removed from a
ive backplane. The device operates with any combination of 2.7V to 16.5V and 2.7V to 16.5V supplies. Using two external N-channel pass transistors, the board supply voltages can be ramped up at an adjustable rate. A selectable tracking mode allows dual supply tracking control for ramping the positive and negative supplies together.

The LT4220 features foldback current limit and latches off both gates if either supply remains in current limit longer than an adjustable time period. The IC can be configured for automatic restart after a delay set by the same timer.

A power good signal indicates when the output voltages monitored by the two FB comparators are within tolerance, and the gate drive signals are at their full on voltage. The LT4220 is available in a 16-lead narrow SSOP
package.