Test Procedure for the NCV8842PWGEVB Evaluation Board NCV8843 Demo Board Test Setup: Figure 1: Test Setup Equipment: Required Equipment Equipment Basic Specifications Tektronix TDS 754C Keithley 179-20A HP 33120A Function Generator XANTREX XHR 60-18 DC Power Supply KIKUSUI PL2 72 W Electronic Load NCV8842 Demo Board Dual Channel Oscilloscope DC Voltmeter 0.04% + 1 digit 193 – 237 kHz pulse at 20% duty cycle 7 to 16 V @ 1A 1.0 A load at 3.3 V input 7 – 16 V to 2.5-5.0 V @ 1.0 A Buck Regulator Table 1: Showing equipment needed to perform test procedures Pin Descriptions: 8/30/2012 Connections Description J1, J5 and J8 J2 J3 J4 J6 J7 GND Supply input (7 V to 16 V) Switch Node (SWN) Vout (2.5, 3.3 V, or 5.0 V) Sync Pin Shutdown (SHDNB) Pin -1- www.onsemi.com Test Procedure: Normal Operation 1. Connect the test setup as shown in Figure 1, but with the function generator disconnected. Monitor switch node (SWN, J3) continuously for stability (no jitter). 2. Ensure BR2 jumper is closed to set Vout to 3.30 V. 3. Set the power supply (Vin) to 12.0 V. 4. Without load attached, look at SWN – the part will be in discontinuous conduction mode (DCM), as seen below: Figure 2: Switch-node in DCM 5. Verify that the output voltage (Vout) is within +/- 4% of nominal in DCM. 6. Adjust the electronic load (Iout) to draw a 300 mA load (to get out of DCM). With load attached, look at SWN – the part will be in continuous conduction mode (CCM), as seen below: Figure 3: Switch-node in CCM 7. Verify that the output voltage (Vout) is within +/- 4% of nominal in CCM. 8. Measure the switching frequency via channel 1 (170.0 kHz +/- 10%). 9. Set Iout to 1 A and vary Vin from 7.0 V to 16 V. Verify that Vout does not change more than approximately .02 % (typical line regulation). 10. Set Vin to 7.0 V and vary Iout from 300 mA to 1.0 A. Verify that Vout does not change more than approximately .15 % (typical load regulation). 11. Repeat Normal Operation, steps 3-8 for 2.50 V (BR1) and 5.00 V (BR3) options. Shutdown mode 1. Short J7 (SHDNB) to J8 (GND). 2. Switching should stop and Vout should go to 0 V. 3. Remove short. 4. Vout should ramp up back into regulation. Sync Function 1. Set the function generator 40 to 50 kHz higher than the switching frequency measured in step 7 of Normal Operation. 2. Disable the generator’s output and connect it to sync (J6) and ground (J8) (see Figure 1). 3. While observing the oscilloscope’s waveforms (CH1 and CH2), enable the function generator and verify that CH1 tracks CH2. 8/30/2012 -2- www.onsemi.com