2
dc1905af
DEMO MANUAL DC1905A
Quick start proceDure
Demonstration circuit DC1905A is an easy way to evalu-
ate the performance of the LTM4633EY. 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
RUN3
MODE
ON
ON
ON
CCM
2. With power off, connect the input power supply, loads
and meters as shown in Figure 1. Preset the load to 0A
and V
IN
supply to 12V.
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
1.2V ±1.5% (1.182V to 1.218V). The output voltage of
channel 3 should be 3.3V ±1.5% (3.25V to 3.349V).
4. Vary the input voltage from 4.7V to 16V and adjust the
load current of each channel from 0A to 10A. Observe
the output voltage regulation, ripple voltage, efficiency,
and other parameters.
5. (Optional) For optional load transient test, apply an
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
respectively.
6. (Optional) LTM4633 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 LTM4633 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 20A polyphase operation on DC1905A. Install
0Ω resistors on R32, R33, R35, R36 and remove R15.
Output voltage is set by R4 based on equation V
OUT
=
0.8V (1 + 60.4k/2/R4).
performance summary
Specifications are at T
A
= 25°C
PARAMETER
CONDITIONS
VALUE
Input Voltage Range
4.7V to 16V
Output Voltages
1.0V, 1.2V, 3.3V ±1.5%
Maximum Continuous Output Current
Derating Is Necessary for Certain Operating Conditions.
See Data Sheet for Details
10ADC for Each Channel
Operating Frequency
750kHz
Efficiency of Channel 1
V
IN
= 12V, V
OUT1
= 1.0V, I
OUT1
= 10A
77% See Figure 2
Efficiency of Channel 2
V
IN
= 12V, V
OUT2
= 1.2V, I
OUT2
= 10A
81% See Figure 3
Efficiency of Channel 3
V
IN
= 12V, V
OUT3
= 3.3V, I
OUT3
= 10A
91% See Figure 4
Load Transient of Channel 1
V
IN
= 12V, V
OUT1
= 1.0V, I
STEP
= 0A to 5A
See Figure 5
Load Transient of Channel 2
V
IN
= 12V, V
OUT2
= 1.2V, I
STEP
= 0A to 5A
See Figure 6
Load Transient of Channel 3
V
IN
= 12V, V
OUT3
= 3.3V, I
STEP
= 0A to 5A
See Figure 7
