DEMO MANUAL DC2969A
LTC4372, LTC4373
Low Quiescent Current Dual
Ideal Diodes
DESCRIPTION
The DC2969A circuit board enables evaluation of the circuits includes a high side load switch in series with the
LTC 4372 and LTC4373 low quiescent current ideal diode ideal diode allowing load on/off control with the SHDN/
controllers. The DC2969A-A option is assembled with the UV jumper. In addition, input dropouts are blocked from
LTC4372 controller, whereas DC2969A-B is assembled the output, permitting capacitors to hold up the load when
with the LTC4373 controller. DC2969A includes two inde- input power fails. Each channel can carry up to 20A.
pendent ideal diode circuits sharing a common ground,
Design files for this circuit board are available.
operating over a 2.5V to 33V range, and protecting the
All registered trademarks and trademarks are the property of their respective owners.
load against reverse inputs of up to 28V. One of these
PERFORMANCE SUMMARY Specifications are at T = 25C
A
PARAMETER CONDITIONS MIN TYP MAX UNITS
Voltage Limits VIN Operating 2.5 33 V
VINA DC Survival 28 50 V
VINB DC Survival 28 36 V
Undervoltage Threshold (DC2969A-B VINB Only) VINB Rising 2.80 3 3.20 V
VINB Falling 2.35 2.5 2.65 V
Output Current 2.5V VIN 5V 10 A
5V < VIN 33V 20 A
Rev. 0
1DEMO MANUAL DC2969A
QUICK START PROCEDURE
There are exposed conductors on the bottom of the board, 5. Each channel can be individually controlled by its
and any banana plugs present will protrude through the associated SHDN/UV jumper. For example, if VINB is
bottom of the board. Even though the board is equipped adjusted to 12V and VINA is set to 10V, VINB sup-
with standoffs, the underlying surface should be non- ply will source the entire load current. If SHDNB/UVB
conductive and clear of any wire, solder, and other con- jumper is subsequently set to HI for DC2969A-A or
ductive debris. LO for DC2969A-B, channel B will turn off and the full
load current will be provided by channel A. Note that
A simple demonstration of DC2969As operation is as
turning off channel A through the SHDNA/UVA jumper
follows:
only turns off the M1A MOSFET channel; the M1A body
1. Position the two SHDN/UV jumpers to enable both
diode always provides a parallel current path. Do not
channels: LO for DC2969A-A, HI for DC2969A-B.
flow more than 2A through the MOSFET body diode,
else M1A may heat up to destruction. Positioning chan-
2. Connect two adjustable power supplies, initially turned
nel B jumper at DIV (DC2969A-B only) provides a 3V
off or set to 0V. Connect one supply to VINA and nearby
rising and 2.5V falling undervoltage lockout threshold
GND, the second to VINB and its associated GND (see
on VINB. Unless the SHDNB/UVB turret is being driven,
Figure1). Join the outputs of VOUTA and VOUTB at the
do not use DIV position for DC2969A-A as it floats the
input of a 10A capable DC load, initially turned off or
SHDN pin.
set to 0A.
6. Dial any supply below ground up to 28V and check
3. Adjust one power supply to 12V. Set the DC load to
that the output voltage is limited to roughly 1V.
10A. Check that the output is roughly within 50mV of
the input.
4. Slowly adjust the other power supply up and down
relative to the first while monitoring the power supply
currents. The higher supply will carry the load current,
with a narrow transition region where the input volt-
ages are nearly identical and the supplies droop share.
If one supply is turned off or shorted, the output volt-
age will not collapsethe other supply will carry the
load.
Rev. 0
2