AN2808 datasheet(17/40 Pages) STMICROELECTRONICS

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AN2808

Getting started

17/40

Getting started

The following step-by-step power-up and power-down sequences are provided in order to

correctly evaluate the performance of the PM6670S board.

9.1

Power-up sequence

Working in an ESD-protected environment is highly recommended. Check all wrist straps

and mat earth connections before handling the PM6670S board. Connect the power

supplies as shown in the PM6670S test setup (Figure 14) and insert the meters in order to

perform the desired performance evaluation. Connect the scope probes as desired.

Set the JP1, JP2, JP3 and JP5 jumpers in order to properly configure the PM6670S

board.

Set the S3-S5 switches to the ON (upper) position. Do not change the jumper settings

when the board is powered.

Set the VCC supply to 5 V ± 5% and the current limit to 100 mA.

Set the VIN supply to a voltage in the range of 4.5 to 28 V. An initial test at 12 V and 3 A

current limit is suggested.

Set all the loads to 0 A.

Turn on the VIN supply.

Turn on the VCC supply.

Vary the VDDQ load from 0 A to 10 A.

Vary the VTT load from 0 A to 2 A to test the source capability. To test the sink

capability use the dashed VTT load shown in Figure 14.

10. Vary the VTTREF load to test the source capability.

11. Vary the VIN supply from 4.5 to 28 V.

9.2

Power-down sequence

Decrease the VTTREF and VTT loads to 0 A.

Reduce the VDDQ load to 5 A.

Decrease the VCC supply from 5 to 3.8 V in order to test the UVLO.

Increase the VCC supply from 3.8 to 5 V to restart the device.

Use the S3-S5 switches to enter/exit the S0-S3-S5 states.

Turn off the VDDQ load.

Turn off the VCC supply.

Turn off the VIN supply.

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