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DEMO MANUAL DC2268A-B
performance summary
PARAMETER
Input Voltage Range
Output Voltage V
OUT1
Output Voltage V
OUT2
Per-Channel Maximum Continuous Output Current
Default Operating Frequency
Resistor Programmable Frequency Range
External Clock Sync. Frequency Range
Efficiency of Channel 1
Efficiency of Channel 2
Load Transient of Channel 1
Load Transient of Channel 2
Quick start proceDure
Demonstration circuit DC2268A-B is easy to set up to
evaluate the performance of the LTM4620A. It can be
easily inserted to an edge connector (SAMTEC MEC2-
20-01-L-DV--TR) for testing and debugging. Please refer
to Figure 2 for proper measurement setup and follow the
procedure below:
1. Pull up the RUN1 (J1 pin 22) and RUN2 (J1 pin 24)
between 1.4V to 5V or leave them floating.
2. With power off, connect the input power supply, load
and meters as shown in Figure 1. Preset the load to 0A
and V
supply to 12V.
IN
3. Turn on the power supply at the input. The output volt-
age in channel 1 should be 3.3V ± 1.5% (3.2505V ~
3.3495V) and the output voltage in channel 2 should
be 5V ± 1.5% (4.925V ~ 5.075V),
2
Specifications are at T
A
CONDITIONS
V
= 4.5V ~ 15V, I
= 0A ~ 13A
IN
OUT1
V
= 4.5V ~ 15V, I
= 0A ~ 13A
IN
OUT2
Derating Is Necessary for Certain V
Conditions.
V
= 12V, V
= 3.3V, I
= 13A, f
IN
OUT2
OUT2
V
= 12V, V
= 5V, I
= 13A, f
IN
OUT1
OUT1
V
= 12V, V
= 3.3V, I
= 6.5A ~ 13A
IN
OUT2
STEP
V
= 12V, V
= 5V, I
= 6.5A ~ 13A
IN
OUT1
STEP
4. Once the proper output voltage is established, adjust the
load within the operating range and observe the output
voltage regulation, output voltage ripple, efficiency and
other parameters. Output ripple should be measured
at Co3 and Co4.
5. (Optional) LTM4620A can be synchronized to an exter-
nal clock signal. Remove R2 and apply a clock signal
(0~5V, square wave) to MODE-PLLIN pin.
6. (Optional) LTM4620A can be configured for a 2-phase
single output at up to 36A on DC2268A-B. Install 0Ω
resistors on R26, R27, R28, R29, R32, and remove
R14, R18, R30. Output voltage is set by R7 based on
equation V
= 25°C
, V
and Thermal
IN
OUT
= 750kHz
SW
= 750kHz
SW
= 0.6V(1 + 60.4k/R7).
OUT
VALUE
5.5V ~ 16V
3.3V ±1.5%
1.5V ±1.5%
13A
750kHz
250kHz to 780kHz
400kHz to 780kHz
91.8% See Figure 3
93.9% See Figure 4
See Figure 5
See Figure 6
dc2268abfa
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