Linear Technology LTC2923 Quick Start Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 732
DESCRIPTION
Demonstration circuit 732 allows evaluating perform-
ance of the LTC2923 Power Supply Tracking Controller
which is intended to provide hot swapping of one not
regulated voltage source (master supply) and tracking
or sequencing of two other regulated power supplies
via current injection into their respective feedback
nodes.
The DC732 provides two different configurations on
one snap apart circuit board.
Table 1. Performance Summary (T
PARAMETER
Supply Voltage
Under voltage lockout
ON Pin Threshold
ON Pin Hysteresis
Gate Pin Current
FET Drain-Source Overcurrent Voltage Threshold (V
V )
RAMP
Fixed Rail Current Capability
Track Pin Voltage
Feedback Pin Compliance
Feedback Node Control Current
POWER SUPPLY TRACKING AND SEQUENCING CONTROLLER
= 25°C)
A
CONDITION
Rated operating limits
V rising
CC
Precision threshold accurately holds off power supplies until
both supplies are fully up
Gate On : V =0V, No Faults
GATE
Gate Off: V
GATE
Gate Fault: V
GATE
-
FET Over Current Sensed by Drain-Source Voltage
CC
Limited by Si4412 MOSFET (To Control Higher Current Re-
place MOSFET with a Larger Device)
Regulated Power Supplies Feedback Voltage Must be Less
Than 1.5V
V • 1.5V
FB
Circuit 1 provides for tracking of two regulated sup-
plies via feedback node current injection.
Circuit 2 provides an additional pass FET to control a
third fixed rail on a larger board. Both boards provide
very small footprints for easy installation into existing
systems.
Design files for this circuit board are available. Call
the LTC factory.
Linear
LTC is a trademark of
=5V, No Faults
=5V, Short-Circuit Fault
LTC2923
Technology Corporation
VALUE
2.9 • V • 5.5V
CC
2.2V • V • 2.7V
CC
1.212 • V • 1.248V
VON(TH)
30mV• ˜V •150mV30A
ON(HYS)
-7µA • • -13 µA
GATE
7 µA • I • 13 µA
GATE
5mA • I • 50mA
GATE
160mV • V • 240mV
DSTH
4A Max
0.776V • V • 0.824V
TRACK
0V • V • 1.5V
FB
1V MIN
1