LTC4210-3CS6 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
LTC4210-3CS6 Datasheet PDF : 16 Pages
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BLOCK DIAGRA
INITIAL UP/LATCH OFF
5µA 60µA
CURRENT LIMIT
TIMER
1
0.2V +
COMP1
–
+
COMP2
1.3V –
INITIAL DOWN/NORMAL
GND
2
2µA 100µA
COOL OFF
LTC4210-3/LTC4210-4
6
VCC
UVLO
GLITCH
FILTER
5
SENSE
50mV
–+
EA
LOGIC
GLITCH
FILTER
Z1
12V
SHUTDOWN
CHARGE
PUMP
10µA
4k
M5
GATE
4
Z2
26V
COMP3
–+
1.3V
ON
3
4210 BD
APPLICATIO S I FOR ATIO
Hot Circuit Insertion
When circuit boards are inserted into live backplanes, the
supply bypass capacitors can draw large transient cur-
rents from the backplane power bus as they charge. Such
transient currents can cause permanent damage to con-
nector pins, glitches on the system supply or reset other
boards in the system.
The LTC4210 is designed to turn a printed circuit board’s
supply voltage ON and OFF in a controlled manner, allow-
ing the circuit board to be safely inserted into or removed
from a live backplane. The LTC4210 can reside either on
the backplane or on the daughter board for hot circuit
insertion applications.
Overview
The LTC4210-3/LTC4210-4 is designed to operate over a
range of supplies from 2.7V to 7V. Upon insertion, an
undervoltage lockout circuit determines if sufficient sup-
ply voltage is present. When the ON pin goes high an initial
timing cycle assures that the board is fully seated in the
backplane before the MOSFET is turned on. A single timer
capacitor sets the periods for all of the timer functions.
After the initial timing cycle the LTC4210 can either start
up in current limit or with a lower load current. Once the
external MOSFET is fully enhanced and the supply has
ramped up, the LTC4210 monitors the load current through
an external sense resistor. Overcurrent faults are actively
limited to 50mV/RSENSE for a specified circuit breaker
timer limit. The LTC4210-3 will automatically retry after a
current limit fault while the LTC4210-4 latches off. The
LTC4210-3 timer function limits the retry duty cycle to
3.8% for MOSFET cooling.
421034fa
7
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