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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 802
across the Vin or Vout and GND terminals. See
Following table should be the default jumper settings of the DC802A demo board:
1.
With the above default setting, the supply runs at 550kHz forced continuous current mode.
Following tables show the assembly options for the tracking circuits for VOUT1 and VOUT2:
1
*
2
3
1
2
3
*
*With existing tracking circuit assembly, VOUT1 starts independently (option1). VOUT2 tracks VOUT1 during start
up (option3). Figure 3 shows a typical start-up waveform with tracking.
With power off, connect the input power supply to
2.
VIN and GND. Connect the load between VOUT1
and GND, VOUT2 and GND. Preset the load current
at 0A (minimum). Refer to Figure 1 for correct test
set up.
Turn on the input power.
3.
Make sure that the input voltage does not ex-
NOTE:
ceed 21V.
LTC3828 DUAL 2-PHASE STEP DOWN CONVERTER WITH TRACKING
JP1
JP2
JP3
PHSMD
FSET
FCB
0
550kHz
CCM
VOUT1 TRACKING
OPTIONS
Softstart W/O tracking
Track EXT1
Track VOUT2
VOUT2 TRACKING
OPTIONS
Softstart W/O tracking
Track EXT2
Track VOUT1
Figure 2 for proper scope probe technique.
JP4
JP5
JP6
RUN1
RUN2
TRACK2
ON
ON
VOUT1
TRACK2 JP6
R23
N/A
DNP
EXT1
105K
VOUT2
105K
TRACK1 JP7
R24
N/A
DNP
EXT2
95.3K
VOUT1
95.3K
Check for the proper output voltages. Vout1 =
4.
4.90V-5.10V. Vout2 = 3.23V- 3.36V
If there is no output, temporarily disconnect
NOTE:
the load to make sure that the load is not set too
high.
Once the proper output voltages are established,
5.
adjust the loads within the operating range and ob-
serve the output voltage regulation, ripple voltage,
efficiency and other parameters.
JP7
TRACK1
EXT1
R25
C21
DNP
0.01uF
20K
DNP
20K
DNP
R26
C22
DNP
0.01uF
30.1K
DNP
30.1K
DNP
2
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