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dc2202af

DEMO MANUAL DC2202A

Quick start proceDure

Demonstration circuit 2202A is easy to set up to evalu-

ate the performance of the LT8640. Refer to Figure 4 for

proper measurement equipment setup and follow the

procedure below:

NOTE: When measuring the input or output voltage ripple,

care must be taken to avoid a long ground lead on the

oscilloscope probe. Measure the input or output voltage

scope technique.

1. Place JP1 on BURST position.

andGND.IftheEMI/EMCperformanceisnotimportant,

the input EMI filter can be bypassed by connecting the

4. Turn on the power at the input.

NOTE: Make sure that the input voltage does not exceed

42V.

NOTE: If there is no output, temporarily disconnect the

load to make sure that the load is not set too high or

is shorted.

6. Once the proper output voltage is established, adjust

the load within the operating ranges and observe the

output voltage regulation, ripple voltage, efficiency and

other parameters.

7. An external clock can be added to the SYNC terminal

whenSYNCfunctionisused(JP1ontheSYNCposition).

Please make sure that RT should be chose to set the

LT8640 switching frequency equal to or below the low-

est SYNC frequency. JP1 can also set LT8640 in spread

spectrum mode (JP1 on the SPREAD-SPECTRUM

position) or pulse-skipping mode (JP1 on the PULSE-

SKIPPING position).

Figure 4. Proper Measurement Equipment Setup

GND

Figure 5. Measuring Output Ripple