Datasheet

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Test Procedure

Table 6. Master Enable Selection

Jumper set to Enable/Disable Controller

Jumper shorts on J4 Disable 1.5-V Master output

No Jumper on J4 Enable 1.5-V Master output

5.6 Slave Enable (J9: EN_SLV)

The Slave Enable can be set by J9.

Default setting: Jumper on J9,

Table 7. Slave Enable Selection

Jumper set to Enable/Disable Controller

Jumper shorts on J9 Disable 1.2-V Master output

No Jumper on J9 Enable 1.2-V Master output

6 Test Procedure

6.1 Line/Load Regulation and Efficiency Measurement Procedure

1. Ensure that the Load1 and Load2 are set to constant resistance mode and sink 0 A.

2. Ensure that all jumper configuration settings are per Section 5.

3. Ensure that jumpers short on J4, J9 before Vin is applied.

4. Increase Vin from 0 V to 3.3 V, using V1 to measure input voltage.

5. Remove jumper from J4 to enable the master controller.

6. Vary Load1 from 0 A to 3 A; 1.5-V master output must remain in load regulation.

7. Vary Vin from 2.9 V to 3.5 V; 1.5-V master output must remain in line regulation.

8. Remove jumper from J9 to enable the slave controller.

9. Vary Load2 from 0 A to 3 A; 1.2-V slave output must remain in load regulation.

10. Vary Vin from 2.9 V to 3.5 V; 1.2-V slave output must remain in line regulation.

11. Measure the waveforms of SW_MST(TP6) and SW_SLV(TP18) to see master-slave 180° interleaved.

12. Put jumpers on J4 and J9 to disable master and slave controller.

13. Decrease Load1 and Load2 to 0 A.

14. Decrease Vin to 0 V.

6.2 Loop Gain/Phase Measurement

1. Set up EVM as described in Section 6.1 and Figure 3. Measure 1.5-V bode plot.

2. Connect the isolation transformer to CHA_MST and CHB_MST.

3. Connect input signal CHA to TP1 (CHA_MST) and connect output signal CHB to TP2 (CHB_MST).

4. Connect the GND lead of CHA and CHB to TP25 (GND).

5. Inject approximately 50-mV or less signal through the isolate transformer.

6. Sweep the frequency from 500 Hz to 1 MHz with 10-Hz or lower post filter. The control loop gain and

phase margin can be measured.

7. Disconnect isolate transformer from the bode plot setup before making other measurements. (Signal

injection into feedback may interfere with accuracy of other measurements.)

8. The loop measurement for 1.2-V slave output is the same as with a 1.5-V master output.

6.3 List of Test Points

SLUU428A–July 2010–Revised November 2010 Using the TPS53311EVM-561, a 3-A Eco-mode™ Integrated Switcher With

Master-Slave

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