2
UG-1329 Rev D
DEMO MANUAL
DC2268A-H
QUICK START PROCEDURE
PERFORMANCE SUMMARY
Specifications are at TA = 25°C
PARAMETER CONDITIONS/NOTES VALUE
Input Voltage Range 4.5V ~ 15V
Output Voltage VOUT1 VIN = 4.5V ~15V, IOUT1 = 0A ~25A 1V ± 1.5%
Output Voltage VOUT2 VIN = 4.5V ~15V, IOUT2 = 0A ~25A 1.5V ± 1.5%
Per Channel Maximum Continuous Output Current Derating is necessary for certain VIN, VOUT and thermal conditions 25A (per channel)
Default Operating Frequency 500kHz
External Clock Sync. Frequency Range 400kHz to 780kHz
Efficiency of Channel 1 VIN = 12V, VOUT1 = 1.0V, IOUT1 = 25A, fSW = 500kHz 86.3% (see Figure 3)
Efficiency of Channel 2 VIN = 12V, VOUT2 = 1.5V, IOUT2 = 25A, fSW = 500kHz 89.0% (see Figure 3)
Load Transient of Channel 1 VIN = 12V, VOUT1 = 1V, ISTEP = 12.5A ~ 18.75A VOPP = 77mV (see Figure 4)
Load Transient of Channel 2 VIN = 12V, VOUT2 = 1.5V, ISTEP = 12.5A ~ 18.75A VOPP = 84mV (see Figure 5)
Demonstration circuit DC2268A-H is easy to set up to
evaluate the performance of the LTM4650-1. 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 measurement setup and follow the
procedure below:
1. Pull-up the RUN1 (J1 pin 22) and RUN2 (J1 pin 24)
between 1.4V – 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 VIN 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 ~
1.015V) and the output voltage in channel 2 should be
1.5V ± 1.5% (1.478V ~ 1.523V).
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 CO3 and CO4.
5. (Optional) LTM4650-1 can be synchronized to an exter-
nal clock signal. Remove R2 and apply a clock signal
(0V~5V, square wave) to MODE-PLLIN pin.
6. (Optional) LTM4650-1 can be configured for a 2-phase
single output at up to 20A on DC2268A-H. Install 0Ω
resistors on R26, R27, R28, R29 and R32, and remove
R14, R18 and R30. Output voltage is set by R7 based
on equation VOUT = 0.6V (1 + 60.4k/R7).
NOTE: Due to very small PCB size of the DC2268A
board, the LTM4650-1 module can be quite hot at
heavy load. Cooling air is required. See Figures 6 and 8.
Table 1. 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