LTC2924CGN View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC2924CGN' PDF : 22 Pages View PDF
Applications Information
VCC
RHYS ON
TMR
VCC
HYS/CFG GND
ON LTC2924 PGT
IN1
OUT1
IN2
OUT2
IN3
OUT3
IN4
OUT4
DONE
FAULT
RHYS
TMR
VCC
HYS/CFG GND
ON LTC2924 PGT
IN1
OUT1
IN2
OUT2
IN3
OUT3
IN4
OUT4
DONE
FAULT
VCC
10k
DONE
VCC
10k
FAULT
2924 F07
Figure 7. Cascading Two LTC2924s to Fully Sequence Up to Eight Power Supplies
VCC
LTC2924
RHYS ON
TMR
VCC
HYS/CFG GND
ON LTC2924 PGT
IN1
OUT1
IN2
OUT2
IN3
OUT3
IN4
OUT4
DONE
FAULT
RHYS
TMR
VCC
HYS/CFG GND
ON LTC2924 PGT
IN1
OUT1
IN2
OUT2
IN3
OUT3
IN4
OUT4
DONE
FAULT
RHYS
TMR
VCC
HYS/CFG GND
ON LTC2924 PGT
IN1
OUT1
IN2
OUT2
IN3
OUT3
IN4
OUT4
DONE
FAULT
VCC
10k
DONE
VCC
10k
FAULT
2924 F08
Figure 8. Cascading Three LTC2924s to Fully Sequence Up to 12 Power Supplies
Cascading Multiple LTC2924s
Two or more LTC2924s may be cascaded to fully sequence
8,12 or more power supplies. Figures 7 and 8 show how
to configure the LTC2924 to sequence 8 and 12 power
supplies. To sequence more power supplies, use the circuit
in Figure 8 and add more LTC2924s in the middle.
Notice that the last LTC2924 in the cascade string must
have a pull-up resistor on the DONE pin. Any LTC2924
that is not the first in the cascade string should have the
hysteresis current setting resistor, RHYS, pulled to VCC
instead of ground. The value of the RHYS resistor remains
unchanged. The FAULT pins should all be connected to-
gether and pulled up with a single 10k resistor.
Care should be taken when designing a circuit cascading
multiple LTC2924s. Use the following guidelines:
• All VCC and ground pins for the LTC2924s in the cascade
chain must be connected to the same power supply.
• The ground pins should be connected via a ground
plane.
• Cascaded LTC2924s communicate using a combination
of levels and pulses which do not look like the normal
output of a DONE pin nor input to an ON pin. Do not
connect any other components to the node between
the DONE and ON pins. Keep the parasitic capacitance
on this node below 75pF. Care should be taken when
routing a circuit trace between DONE and ON. If pos-
sible, run the trace adjacent to the ground plane, and/
or shield the trace with a ground trace on either side.
Leakage currents must be maintained below 2µA on
this node.
2924fc
For more information www.linear.com/LTC2924
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