AN2798 datasheet(17/38 Pages) STMICROELECTRONICS

17 / 38 page

AN2798

Getting started

17/38

Getting started

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

correctly evaluate the PM6670AS board performance.

7.1

Power-up sequence

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

and mat-earth connections before handling the PM6670AS board.

Connect power supplies as shown in the PM6670AS test setup (Figure 13) and insert

the meters in order to perform the desired performance evaluation. Connect the scope-

probes as desired.

Set the JP1 through JP5 jumpers in order to properly configure the PM6670AS board.

Set the S3-S5 switches to the on position (upper position). Do not change any of 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 4.5 V to 36 V. An initial test at 24 V and 3 A

current limit is suggested.

Set all loads to 0 A.

Turn on the VIN supply.

Turn on the VCC supply.

Vary the VDDQ load from 0 A to 8 A.

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

the dashed VTT load shown in Figure 13.

10. Vary the VTTREF load to test source capability.

11. Vary the VIN supply from 4.5 V to 36 V.

7.2

Power-down sequence

Decrease the VTTREF and VTT loads to 0 A.

Reduce the VDDQ load to 0.

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

Increase the VCC supply from 3.8 V 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.

AN2798 Datasheet(PDF) 17 Page - STMicroelectronics