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Test Procedure
Remove the current probe from the 3.3 V supply lead, and clamp it across the 12VIN2 supply lead.
Change the Channel 4 amplifier setting to 5 A/div. Set the time base to 500 S/div, and adjust the scope
trigger threshold to about 3 volts.
On the EVM board, place the SLOT B PWR ENABLE switch to the LO position. The SLOT B PWR green
LED should illuminate. On the scope, verify a waveform capture was obtained similar to that shown in
. The total voltage ramp time of the Channel 2 trace, from 0 volts to about 11.8 V should be 1.3
0.3 mS. Note that the extent of variance of the 12-V supply setting from a nominal 12.0 V affects this
timing result. A linearly ramping waveform should be visible on the Channel 3 trace, terminating some time
after the output (Channel 2) charges to input potential. The average amplitude of the current pulse (i.e.,
across the flattest part of the peak) on Channel 4 should be 7.9 0.8 A. A DVM can be used to verify the
voltage at TP10 (with respect to ground at TP12) is essentially the same as the input supply potential at
12VIN2.
Figure 6. Output Ramp-up Waveforms – 12B Rail
SLUU328 – August 2008
TPS2358 Dual-Slot ATCA™ AdvancedMC™ Controller Evaluation Module
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