2
dc2268acf
DEMO MANUAL
DC2268A-C
Quick start proceDure
Demonstration circuit DC2268A-C is easy to set up
to evaluate the performance of the LTM4628. 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 and 5V or leave them floating.
2. With power off, connect the input power supply, load
and meters as shown in Figure 2. Preset the load to 0A
and V
IN
supply to 12V.
3. Turn on the power supply at the input. The output volt-
age in channel 1 should be 1.0V ± 1.5% (0.985V be
~1.015V) and the output voltage in channel 2 should
be 1.5V ±1.5% (1.4775V to ~1.5225V),
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 C
O3
and C
O4
.
5. (Optional) LTM4628 can be synchronized to an external
clock signal. Remove R2 and apply a clock signal (0~5V,
square wave) to MODE-PLLIN pin.
6. (Optional) LTM4628 can be configured for a 2-phase
single output at up to 16A on DC2268A-C. Install 0Ω
resistors on R26, R27, R28, R29, R32, and remove
R14, R18 and R30. Output voltage is set by R7 based
on the equation: V
OUT
= 0.6V (1 + 60.4K/R7).
performance summary
Specifications are at T
A
= 25°C
PARAMETER
CONDITIONS
VALUE
Input Voltage Range
5.5V to ~16V
Output Voltage V
OUT1
V
IN
= 4.5V to ~16V, I
OUT1
= 0V to ~8A
1.0V ± 1.5%
Output Voltage V
OUT2
V
IN
= 4.5V to ~16V, I
OUT2
= 0V to ~8A
1.5V ± 1.5%
Per-channel Maximum Continuous Output Current
Derating is necessary for certain V
IN
, V
OUT
and thermal conditions.
8A (per channel)
Default Operating Frequency
500kHz
Resistor Programmable Frequency Range
250kHz to 780kHz
External Clock Sync. Frequency Range
400kHz to 780kHz
Efficiency of Channel 1
V
IN
= 12V, V
OUT2
= 1.0V, I
OUT2
= 8A, f
SW
= 500kHz
80.7% See Figure 3
Efficiency of Channel 2
V
IN
= 12V, V
OUT1
= 1.5V, I
OUT1
= 8A, f
SW
= 500kHz
84.6% See Figure 4
Load Transient of Channel 1
V
IN
= 12V, V
OUT2
= 1.0V, I
STEP
= 4A to 6A
V
OPP
= 56mV See Figure 5
Load Transient of Channel 2
V
IN
= 12V, V
OUT1
= 1.5V, I
STEP
= 4A to 6A
V
OPP
= 67mV See Figure 6