Datasheet

Test Procedure

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7.3 Loop Gain/Phase Measurement

CPU and GPU Only

1. Set up EVM as described in Section 5.1 and Figure 7.

2. CPU: Connect the isolation transformer to VSNS of J101 (CPU) and Vcore_C (+)(CPU) of J102.

GPU: Connect the isolation transformer to VSNS of J201 (GPU) and Vcore_G (+)(GPU) of J202

3. CPU: Connect input signal CHA to VSNS pin of J101 and connect output signal CHB to Vcore_C(+) of

J102.

GPU: Connect input signal CHA to VSNS pin of J201, and connect output signal CHB to Vcore_G(+) of

J202.

4. Connect the GND lead of CHA and CHB to GND of TP116 (CPU) and TP216 (GPU).

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

6. Sweep the frequency from 100 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 measurement).

7.4 Equipment Shutdown

1. Shut down Load.

2. Shut down VIN.

An 8-V to 14-V Vin 2010 Atom™ E6xx— Tunnel Creek Power System SLUU465–November 2010

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