Linear Technology DC2121A Demo Manual page 2

DEMO MANUAL DC2121A
performance summary
PARAMETER
Input Voltage Range
Output Voltages
Maximum Continuous Output Current
Operating Frequency
Efficiency of Channel 1
Efficiency of Channel 2
Efficiency of Channel 3
Load Transient of Channel 1
Load Transient of Channel 2
Load Transient of Channel 3
Quick start proceDure
Demonstration circuit DC2121A is an easy way to evaluate
the performance of the LTM4634. Please refer to Figure
1 for proper measurement equipment setup and follow
the procedure below.
1. Place jumpers in the following positions for a typical
application
RUN1 RUN2
ON ON
2. With power off, connect the input power supply, loads
and meters as shown in Figure 1. Preset the load to 0A
and V supply to 24V.
IN
3. Turn on the power supply at the input. The output
voltage of channel 1 should be 1.0V ± 1.5% (0.985V
to 1.015V). The output voltage of channel 2 should be
3.3V ± 1.5% (3.25V to 3.349V). The output voltage of
channel 3 should be 12.0V ± 1.5% (11.82V to 12.18V).
4. Vary the input voltage and adjust the load current of
channel 1 and channel 2 from 0A to 5A and channel 3
from 0A to 4A. Observe the output voltage regulation,
ripple voltage, efficiency, and other parameters.
5. (Optional) For optional load transient test, apply an
2
CONDITIONS/NOTES
Derating Is Necessary for Certain Operating Conditions.
See Data Sheet for Details.
V = 12V, V = 1.0V, I
IN OUT1
V = 12V, V = 3.3V, I
IN OUT2
V = 24V, V = 12.0V, I
IN OUT3
V = 12V, V = 1.0V, I
IN OUT1
V = 12V, V = 3.3V, I
IN OUT2
V = 24V, V = 12.0V, I
IN OUT3
RUN3 MODE
ON CCM
= 5A
OUT1
= 5A
OUT2
= 4A
OUT3
= 0A to 2.5A
STEP
= 0A to 2.5A
STEP
= 0A to 2A
STEP
adjustable pulse signal between IOSTEP_CLK and GND
test points. The pulse amplitude sets the load step cur-
rent amplitude. Keep the pulse width short (<1ms) and
pulse duty cycle low (<5%) to limit the thermal stress
on the load transient circuit. Switch the jumper resistors
R30, R31 or R34 (on the backside of boards) to apply
load transient on channel 1, channel 2, or channel 3
correspondingly.
6. (Optional) LTM4634 can be synchronized to an external
clock signal. Place the JP4 jumper on EXT_CLK and
apply a clock signal (0V to 5V, square wave) on the
CLKIN test point.
7. (Optional) The outputs of LTM4634 can track another
supply. If tracking external voltage is selected, the cor-
responding test points, TRACK1, TRACK2, and TRACK3,
need to be connected to a valid voltage signal.
8. (Optional) Channel 1 and 2 can be connected in paral-
lel for a 10A polyphase operation on DC2121A. Install
0Ω resistors on R32, R33, R35, R36 and remove R15.
Output voltage is set by R4 based on equation:
60.4k
⎛
⎜
2
V = 0.8V +1
⎜
OUT
R4
⎜
⎝
VALUE
4.75V to 28V
1.0V, 3.3V, 12.0V ± 1.5%
5ADC for Ch1
5ADC for Ch2
4ADC for Ch3
500kHz
79.7% See Figure 2
91% See Figure 3
94.5% See Figure 4
See Figure 5
See Figure 6
See Figure 7
⎞
⎟
⎟
⎟
⎠
dc2121af