LTC4221_15 Datasheet, PDF (1/28 Pages) Linear Technology – Dual Hot Swap Controller/ Power Sequencer with Dual Speed, Dual Level Fault Protection

LTC4221
Dual Hot Swap Controller/
Power Sequencer with Dual Speed,
Dual Level Fault Protection
FEATURES
■ _{Allows Safe Board Insertion and Removal from a}
Live Backplane
■ _{Configurable Power Supply Sequencing}
■ _{Soft-Start with Current Foldback Limits Inrush}
Current
■ _{No External Gate Capacitor Required}
■ _{Adjustable Dual Level Circuit Breaker Protection}
■ _{Controls Supply Voltages from 1V to 13.5V}
■ _{Independent N-Channel MOSFET High Side Drivers}
■ _{FB Pin Monitors VOUT for Overvoltage Protection}
■ _{Latch Off or Automatic Retry on Current Fault}
■ _{FAULT and PWRGD Outputs}
■ _{Narrow 16-Pin SSOP Package}
U
APPLICATIO S
■ _{Electronic Circuit Breaker}
■ _{Power Supply Sequencing}
■ _{Live Board Insertion and Removal}
■ _{Industrial High Side Switch/Circuit Breaker}
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
DESCRIPTIO
The LTC^®4221 is a 2-channel Hot Swap^TM controller that
allows a board to be safely inserted and removed from a
live backplane. Using two independent high side gate
drivers to control two external N-channel pass transistors,
the output voltages can be ramped up with current foldback
to limit the inrush current during the start-up period. No
external compensation capacitors are required at the
GATE pins. The two channels can be configured to ramp up
and down separately or simultaneously for supply volt-
ages ranging from 2.7V to 13.5V and 1V to 13.5V for
channels 1 and 2 respectively.
Each channel has two current limit comparators that
provide dual level and dual speed overcurrent circuit
breaker protection after the start-up period. If any current
sense voltage exceeds 100mV for 1μs or 25mV for the
timeout delay (set by the C_FILTER at the FILTER pin), then
the FAULT latch is set and both GATE pins are pulled low.
The FB pins monitor the respective channel output volt-
ages and provide the inputs for the PWRGD comparators
as well as overvoltage protection.
TYPICAL APPLICATIO
2-Channel Hot Swap Controller
BACKPLANE PCB EDGE
CONNECTOR CONNECTOR
(FEMALE) (MALE)
V_CC1
3.3V
LONG
V_CC2
2.5V
LONG
*
SHORT
10Ω
100nF
21k
0.004Ω IRF7413
0.004Ω IRF7413
*
100nF
10k
10Ω
V_CC1
ON1
SENSE1 GATE1 V_CC2
SENSE2 GATE2 ^14.3k
FB2
5.11k
FAULT
GND
SHORT
13.3k
10k
SHORT
LONG
*SMAJ10 (OPTIONAL)
ON2
FAULT
GND
TIMER
LTC4221
470nF
PWRGD2
PWRGD1
FILTER FB1
1nF
V_OUT1
3.3V/5A
V_OUT2
2.5V/5A
10k 10k
PWRGD2
PWRGD1
20k
5.11k
4221 TA01
4221fa
1