2
dc1989aaf
DEMO MANUAL DC1989A-A
Quick start proceDure
Demonstration circuit 1989A-A is easy to set up to evalu-
ate the performance of the LTM4676EY. Refer to Figure 2
for the proper measurement equipment setup and follow
the procedure below.
1. With power off, connect the input power supply to V
IN
(4.5V to 16V) and GND (input return).
2. Connect the output load between V
OUT0
and GND (Initial
load: no load).
3. Connect the DVMs to the input and outputs. Set default
switch position: SW1: ON; SW2: ON.
4. Turn on the input power supply and check for the proper
output voltages. V
OUT0
should be 1V ±1%.
5. Once the proper output voltages are established, ad-
just the loads within the operating range and observe
the output voltage regulation, ripple voltage and other
parameters.
6. Connect the dongle and control the output voltages
from the GUI. See “LTpowerPlay GUI for the LTM4676
Quick Start Guide” for details.
Note: When measuring the output or input voltage ripple,
do not use the long ground lead on the oscilloscope probe.
See Figure 3 for the proper scope probe technique. Short,
stiff leads need to be soldered to the (+) and (–) terminals
of an output capacitor. The probe’s ground ring needs to
touch the (–) lead and the probe tip needs to touch the
(+) lead.
Connecting a PC to DC1989A-A
You can use a PC to reconfigure the power management
features of the LTM4676 such as: nominal V
OUT
, margin
set points, OV/UV limits, temperature fault limits, sequenc-
ing parameters, the fault log, fault responses, GPIOs and
other functionality. The DC1613A dongle may be plugged
when V
IN
is present.
performance summary
Specifications are at T
A
= 25°C
PARAMETER
CONDITION
VALUE
Input Voltage Range
4.5V to 16V
Output Voltage, V
OUT0
V
IN
= 4.5 to 16V, I
OUT0
= 0A to 50A
0.5 to 4V, Default: 1V
Maximum Output Current, I
OUT0
V
IN
= 4.5 to 16V, V
OUT
= 0.5V to 4V
50A
Typical Efficiency
V
IN
= 12V, V
OUT
= 1V, I
OUT
= 50A
80.4%
Default Switching Frequency
350kHz
Table 1. LTM4676 Demo Cards for Up to 130A Point-of-Load Regulation
MAXIMUM OUTPUT CURRENT
NUMBER OF OUTPUT VOLTAGES
NUMBER OF LTM4676 µMODULE
REGULATORS ON THE BOARD
DEMO BOARD NUMBER
13A, 13A
2
1
DC1811A
26A
1
1
DC2087A
50A
1
2
DC1989A-A
75A
1
3
DC1989A-B
100A
1
4
DC1989A-C
100A
1
1 (+ 3x LTM4620A)
DC2106A-A
130A
1
1 (+ 3x LTM4630)
DC2106A-B
