Linear Technology DC2268A-1, Demo Manual

Page: 2 / 8

2
dc2268aif
DEMO MANUAL DC2268A-I
QUICK START PROCEDURE
DC2268A-I is easy to set up to evaluate the performance
of the LTM4650A-1. 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 mea-
surement 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 2. Preset the load to 0A
and V
IN
supply to 12V.
3. Turn on the power supply at the input. The output
voltage in channel 1 should be 3.3V ± 1.5% (3.25V ~
3.35V) and the output voltage in channel 2 should be
1.5V ± 1.5% (1.478V ~ 1.523V),
NOTE: Due to very small PCB size of the DC2268A
board, the LTM43650A-1 module can be quite hot at
heavy load. Cooling air is required. See Figures 7 and 8
4. Once the proper output voltage is established, adjust
the load within the operating range and observe the
output voltage regulation, output voltage ripple, effi-
ciency and other parameters. Output ripple should be
measured at C
o3
and C
o4
.
5. (Optional) LTM4650A-1 can be synchronized to an
external clock signal. Remove R2 and apply a clock
signal (0V~5V, square wave) to MODE-PLLIN pin.
6. (Optional) LTM4650A-1 can be configured for a 2-phase
single output at up to 36A on DC2268A-I. Install 0Ω
resistors on R26, R27, R28, R29, R32, and remove
R14, R18 R30. Output voltage is set by R7 based on
equation V
OUT
= 0.6V (1 + 60.4k/R7).
PERFORMANCE SUMMARY
Table 1.
PARAMETER CONDITIONS VALUE
Input Voltage Range 4.5V ~ 16V
Output Voltage V
OUT1
V
IN
= 4.5~16V, I
OUT1
= 0A ~25A 3.3V ± 1.5%
Output Voltage V
OUT2
V
IN
= 4.5~16V, I
OUT2
= 0A ~25A 1.5V ± 1.5%
Per-Channel Maximum Continuous Output Current De-rating is necessary for certain V
IN
, V
OUT
and thermal conditions 25A (per channel)
Default Operating Frequency 600kHz
External Clock Sync. Frequency Range 400kHz to 780kHz
Efficiency of Channel 1 V
IN
= 12V, V
OUT1
= 3.3V, I
OUT1
= 25A, f
SW
= 600kHz 94.4%, see Figure 3
Efficiency of Channel 2 V
IN
= 12V, V
OUT2
= 1.5V, I
OUT2
= 25A, f
SW
= 600kHz 90.0%, see Figure 4
Load Transient of Channel 1 V
IN
= 12V, V
OUT1
= 3.3V, I
STEP
= 12.5A ~ 18.75A V
OPP
= 157mV, see Figure 5
Load Transient of Channel 2 V
IN
= 12V, V
OUT2
= 1.5V, I
STEP
= 12.5A ~ 18.75A V
OPP
= 127mV, see Figure 6
Table 2. DC2268A Demo Circuit
DEMO BOARD NUMBER µModule REGULATOR ON THE BOARD OUTPUT CURRENT
DC2268A-A LTM4620 13A,13A
DC2268A-B LTM4620A 13A,13A
DC2268A-C LTM4628 8A, 8A
DC2268A-D LTM4630 18A,18A
DC2268A-E LTM4630-1 18A,18A
DC2268A-F LTM4630A 18A, 18A
DC2268A-G LTM4631 10A, 10A
DC2268A-H LTM4650-1 25A, 25A
DC2268A-I LTM4650A-1 25A, 25A
Specifications are at T
A
= 25°C