25VT6A5VGEVB 25VT6A5VGEVB Evaluation Board User'sManual Description The 25VT6A5VGEVB evaluation board is designed such that it can accommodate a 1x1 to a 2x2 combination of MOSFETs, for m8−FL and SO8−FL packages. Depending on the type of application and necessity, any combination of the above packages can be used. The 25VT6A5VGEVB evaluation board is designed to operate with an input voltage ranging from 8 V to 16 V, and to provide an output voltage of 0.8 V to 1.8 V for load currents of up to 25 A. The 25VT6A5VGEVB comes with a 5 V driver. The 25VT6A5VGEVB evaluation board has a number of test points that can be used to evaluate its performance in any given application. http://onsemi.com EVAL BOARD USER’S MANUAL • Convenient Test Points for Simple, Non−invasive Measurements of Converter Performance Including Input Ripple, Output Ripple, High Side and Low Side Gate Signals and Switching Node Applications Features • • • • • Synchronous Buck Converters 8 V to 16 V Input Voltage 25 A of Steady State Load Current 500 kHz Switching Frequency Access to IC Features such as Enable, Switching Node and VID Settings for Output Voltage High Frequency Applications High Current Applications ♦ Low Duty Cycle Applications Multi−phase Synchronous Buck Converters ♦ Evaluation Board has only One Phase Implemented ♦ ♦ • Figure 1. 25VT6A5VGEVB Evaluation Board © Semiconductor Components Industries, LLC, 2014 April, 2014 − Rev. 1 1 Publication Order Number: EVBUM2227/D 25VT6A5VGEVB EVALUATION BOARD SCHEMATIC Figure 2. Schematic of the 25VT6A5VGEVB Evaluation Board http://onsemi.com 2 25VT6A5VGEVB ELECTRICAL SPECIFICATIONS Table 1. ELECTRICAL SPECIFICATIONS FOR 25VT6A5VGEVB Parameter Notes and Conditions Min Typ Max Units Input Characteristics Vin Input Voltage − 8 12 16 V Vdrvr Driver Voltage − 4.5 5 6.5 V VCC Controller Voltage − 0 5 7 V Iin Input Current Vin = 12 V; Iout = 25 A 0 − 3 A No load input current Vin = 12 V; Iout = 0 A; Vdrvr = 5 V 0 9 − mA Output Characteristics Vout *Output Voltage Vin = 12 V; Iout = 25 A 0.8 1.2 1.8 V Vp−p Maximum Switch Node Voltage Vin = 12 V; Iout = 20 A; Vdrvr = 5 V − 16 − V Iout Output Current Vin = 8 V to 16 V 0 − 25 A System Characteristics FSW Switching Frequency Note 1 − 500 − kHz hPeak Peak Efficiency Vin = 12 V; Vout = 1.2 V; Vdrvr = 5 V − 91 − % h Full load efficiency Vin = 12 V; Vout = 1.2 V; Vdrvr = 5 V; Iout = 25 A − 87 − % *The output voltage can be adjusted by changing the VID settings. See Appendix. 1. The switching frequency is defined by the resistors R13 and R14 and can only be changed only by changing the resistors R13 and R14. CONNECTORS AND TEST POINTS DESCRIPTIONS Input Power defined in Table 1. The 25VT6A5VGEVB evaluation board is set up to accept DFN8 footprints of ON Semiconductor 5 V drivers. Connect the input voltage positive probe to Pin 1 of J1 and sense probe at J9, negative probe to the GND at Pin 2 of J1 and sense probe at J10. The input voltage can range from 8 V to 16 V. Switching Frequency The converter switching frequency is set by the voltage divider setup of R13 and R14 between the pins 10 (ROSC) and 33 (AGND) of the NCP5386 controller. In order to change the frequency, these resistors have to be changed. Changing the frequency also changes the Ilim (Over Current shutdown threshold) settings. Output Power Connect the output voltage positive probe to J13 (large screw connector) and sense probe at J11, ground probe at J14 (large screw connector) and the sense probe to J12. The output voltage is set by the VID settings (SW2) and the potentiometer (R60). Please refer to Start-Up Procedure and Appendix. Table 2. R13, R14 1% RESISTOR VALUES FOR FREQUENCY SET Controller Biasing Frequency (kHz) R13 (kW) R14 (kW) 300 26.7 7.32 400 19.1 5.23 500 14.7 4.02 Driver Biasing 600 12.1 3.24 The driver positive voltage probe VCC should be connected to both pin 1 and 2 of J6. The driver voltage is 700 10.0 2.74 Connect the positive probe to Pin 2 of J5 and the negative probe to the GND at Pin 1 of J5. Please keep this as a separate supply to avoid damage to the controller, especially when other drive voltages are used. http://onsemi.com 3 25VT6A5VGEVB Test Points Description oscilloscope probes can be inserted into the probe socket and are held in place. The Test Point and the Probe Socket are shown in Figure 3. Monitoring the Input Voltage The input voltage can be monitored by using the test points at J9 and J10 on the 25VT6A5VGEVB evaluation board. This allows the user to find out the exact value of input voltage since there will be no losses from the cables or connectors. Monitoring the PWM Signal The PWM signal from the controller to the driver can be monitored from the probe socket provided at JS11. Monitoring the Output Voltage The 25VT6A5VGEVB evaluation board provides two test points for measuring the output voltage without any losses from the cables or connectors. The output voltage can be measured at the points J11 and J12 on the evaluation board. Monitoring the Switch Node Waveforms The 25VT6A5VGEVB evaluation board provides the opportunity to monitor the switch node waveforms. The probe socket at test point JS8 provides the switch node waveforms. Monitoring the High Side and Low Side Waveforms The high side waveforms can be obtained from the probe socket at test point JS6 and the low side waveforms can be obtained from the probe socket at test point JS10. The probe sockets that are provided on the evaluation board for monitoring the waveforms are such that the Figure 3. Tektronix Test Point & Probe Socket Part #: 700503100 TEST EQUIPMENT REQUIRED Voltage Sources Meters to Measure Voltages and Currents (i) DC Supply Source for Input Voltage The input voltage source should be a 0 to 20 V DC source. The input voltage may be increased further depending on the parts that are being used on the 25VT6A5VGEVB evaluation board such that the part can withstand the applied voltage. Hence, based on the required input voltage to be applied, the requirement of the DC power supply varies. In the 25VT6A5VGEVB Evaluation Board, the voltages that are to be measured are Vin, Vout and Vdrv. The set up for measuring these voltages are shown in Figure 4. The connecting wires from the output terminal to the electronic load should be thicker in order to avoid losses and to measure the exact voltage at the end of the terminals. (ii) DC Supply Source for Driver Voltage The supply source for the driver should be a 0 to 10 V source. The driver voltage should never exceed 6.5 V. The oscilloscope is used to monitor the gate and switch node waveforms. This should be an analog or digital oscilloscope set for DC coupled measurement with 50 MHz bandwidth. The resolution can be set at 5 V/division vertically and 20ns/division horizontally. The oscilloscope channels can be connected at various test points such as high side gate (JS6), low side gate (JS10), switch node (JS8), the driver PWM Signal (JS11), Vin (sense) (J9 & J10) and Vout (sense) (J11 & J12). Oscilloscope Electronic Load The electronic load supplied to the 25VT6A5VGEVB evaluation board ranges from 0 A to 25 A. Hence a DC current source of 0 A to 30 A is needed for the evaluation board. http://onsemi.com 4 25VT6A5VGEVB TEST SET UP AND PROCEDURE Test Setup The test set up, test points and components present on the 25VT6A5VGEVB Evaluation Board are shown in Figure 4. The MOSFET parts placed on the evaluation board are the Q1 and Q4 (Refer to Figure 1). Figure 4. Schematic of the Test Setup Start up and Shut down Procedures reset the controller. The first method is to toggle Pin 8 (EN) of the Grayhill switch (SW2) to 0 (down position) and then back to 1 (up position). The second method is to set VIN to 0 V and then back up to the desired voltage, then turned on and Vin re−established. Before starting the test, the oscilloscope probes should be connected. IR or k−type thermo−couples can be used to monitor the temperature of the parts. IR monitoring requires the removal of the oscilloscope probes due to the IR beam interference. Start up Procedure (VOUT 0.8 V − 1.56 V): 1. Initially set all the power supplies to 0 V. 2. Set the output voltage to the desired value by changing the VID settings on SW2 (see Appendix). The SW2 must be changed while the driver and controller are off. 3. Set the driver voltage and controller voltage to 5 V. 4. Set the input voltage to the desired value (8 V – 16 V). 5. VOUT Adjustments: the output voltage may be fine−tuned at this time, by adjusting the R60 potentiometer. 6. Set the load current to required value. The load current must be incremented slowly to prevent the controller from shutting down due to transient spikes on the inductor current sense lines (CS1, CS2 in Figure 2). If the controller shuts down, there are two different methods that can be used to Start up Procedure (VOUT 1.56 V − 1.8 V): 1. Initially set all the power supplies to 0 V. 2. Set the output voltage to 1.56 V by changing the VID settings on SW2 (see Appendix). The SW2 must be changed while the driver and controller are off. 3. Set the driver voltage and controller voltage to 5 V. 4. Set the input voltage to the desired value (8 V – 16 V). 5. Adjust the output voltage using the R60 potentiometer until the desired output voltage is reached (1.8 V maximum). 6. Set the load current to required value. The load current must be incremented slowly to prevent the controller from shutting down due to transient spikes on the inductor current sense lines (CS1, CS2 in Figure 2). If the controller shuts down, there are two different methods that can be used to http://onsemi.com 5 25VT6A5VGEVB 4. Reduce the driver voltage and controller voltage to zero. Then shut down the driver power supply and controller power supply. reset the controller. The first method is to toggle Pin 8 (EN) of the Grayhill switch (SW2) to 0 (down position) and then back to 1 (up position). The second method is to set VIN to 0 V and then back up to the desired voltage, then turned on and Vin re−established. Test Procedure 1. Before making any connections, make sure to set all power supplies to 0 V, and make sure the load current is 0 A. 2. Connect the oscilloscope probes at the desired test points. 3. Connect the voltmeters/multi−meters to monitor the required parameters. (Refer to Figure 4). 4. Set the output voltage to 1.2 V and the input voltage to 12 V, following the Start−Up Procedure specified in the previous section. 5. Obtain the required data and waveforms. 6. Follow the Shut−Down Procedure specified in the previous section. Shut down Procedure (VOUT 0.8 V − 1.56 V): 1. Shut down the load. 2. Reduce the input voltage to zero and then shut down the input power supply. 3. Reduce the driver voltage and controller voltage to zero. Then shut down the driver power supply and controller power supply. Shut down Procedure (VOUT 1.56 V − 1.8 V): 1. Shut down the load. 2. Adjust the potentiometer until the output voltage measures 1.56 V. 3. Reduce the input voltage to zero and then shut down the input power supply. http://onsemi.com 6 25VT6A5VGEVB TEST RESULTS The following test results were obtained for the 25VT6A5VGEVB evaluation board by following the Test Procedure listed above. The selected MOSFETs were evaluated in a 1 x 1 combination. Figure 5. Efficiency of NTTFS4H07N x NTMFS4H02NF for VIN = 12 V, VOUT = 1.2 V, VDRV = 5 V, FSW = 500 kHz Figure 6. Switch Node and Gate Waveforms of NTTFS4H07N x NTMFS4H02NF taken at IOUT = 20 A http://onsemi.com 7 25VT6A5VGEVB APPENDIX Table of AMD VID Settings for NCP5386B Controller The Grayhill 76PSB08ST 8 position switch used for setting the output voltage of the synchronous buck converter. Figure 7 below shows the pin assignment of the switch. VID0 – VID5 set the output voltage. DAC, and EN is the enable pin of the controller (controller reset). EN must always be in the up position (1) unless a reset is performed. To set the output voltage to 1.2 V, for example: VID0 = 0 (down), VID1, VID2, VID3 = 1 (up), VID4 = 0 (down), and VID5, DAC, EN = 1 (up). Figure 7. Grayhill Switch Pin Labeling Table 3. VID CONTROL SETTINGS FOR OUTPUT VOLTAGE PIN 1 PIN 2 PIN 3 PIN 4 PIN 5 PIN 6 PIN 7 PIN 8 VID0 VID1 VID2 VID3 VID4 VID5 DAC EN VOUT (V) Tolerance 0 0 0 0 0 1 1 1 1.5625 ±0.5% 1 0 0 0 0 1 1 1 1.5375 ±0.5% 0 1 0 0 0 1 1 1 1.5125 ±0.5% 1 1 0 0 0 1 1 1 1.4875 ±0.5% 0 0 1 0 0 1 1 1 1.4925 ±0.5% 1 0 1 0 0 1 1 1 1.4400 ±0.5% 0 1 1 0 0 1 1 1 1.4125 ±0.5% 1 1 1 0 0 1 1 1 1.3875 ±0.5% 0 0 0 1 0 1 1 1 1.3625 ±0.5% 1 0 0 1 0 1 1 1 1.3375 ±0.5% 0 1 0 1 0 1 1 1 1.3125 ±0.5% 1 1 0 1 0 1 1 1 1.2875 ±0.5% 0 0 1 1 0 1 1 1 1.265 ±0.5% 1 0 1 1 0 1 1 1 1.2400 ±0.5% 0 1 1 1 0 1 1 1 1.2125 ±0.5% 1 1 1 1 0 1 1 1 1.1900 ±0.5% 0 0 0 0 1 1 1 1 1.1625 ±0.5% 1 0 0 0 1 1 1 1 1.1375 ±0.5% 0 1 0 0 1 1 1 1 1.1125 ±0.5% 1 1 0 0 1 1 1 1 1.0900 ±0.5% 0 0 1 0 1 1 1 1 1.0650 ±0.5% 1 0 1 0 1 1 1 1 1.0400 ±0.5% 0 1 1 0 1 1 1 1 1.0125 ±0.5% 1 1 1 0 1 1 1 1 0.9875 ±0.5% 0 0 0 1 1 1 1 1 0.9625 ±0.5% 1 0 0 1 1 1 1 1 0.9375 ±0.5% 0 1 0 1 1 1 1 1 0.9125 ±0.5% 1 1 0 1 1 1 1 1 0.8900 ±0.5% 0 0 1 1 1 1 1 1 0.8650 ±0.5% 1 0 1 1 1 1 1 1 0.8400 ±0.5% 0 1 1 1 1 1 1 1 0.8125 ±0.5% 1 1 1 1 1 1 1 1 http://onsemi.com 8 Shutdown 25VT6A5VGEVB Pin Diagram of NCP5386B Controller Figure 8. Top View of the Pin Diagram of NCP5386B Switching Frequency of the Oscillator The switching frequency of the oscillator can only be changed by changing the resistors R13 and R14. For more information on NCP5386B: see Data Sheet of NCP5386B. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner. PUBLICATION ORDERING INFORMATION LITERATURE FULFILLMENT: Literature Distribution Center for ON Semiconductor P.O. Box 5163, Denver, Colorado 80217 USA Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada Fax: 303−675−2176 or 800−344−3867 Toll Free USA/Canada Email: [email protected] N. American Technical Support: 800−282−9855 Toll Free USA/Canada Europe, Middle East and Africa Technical Support: Phone: 421 33 790 2910 Japan Customer Focus Center Phone: 81−3−5817−1050 http://onsemi.com 9 ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative EVBUM2227/D