ISL8225MEVAL4Z

User’s Manual ISL8225MEVAL4Z User’s Manual: Evaluation Board Industrial Analog and Power All information contained in these materials, including products and product specifications, represents information on the product at the time of publication and is subject to change by Renesas Electronics Corp. without notice. Please review the latest information published by Renesas Electronics Corp. through various means, including the Renesas Electronics Corp. website (http://www.renesas.com). Renesas Electronics Corporation www.renesas.com Rev.4.00 Jun.25.19 User’s Manual ISL8225MEVAL4Z Evaluation Board The ISL8225M is a complete, dual step-down switching mode DC/DC power module. The dual outputs can easily be paralleled for single-output, high current use. It is easy to apply this high-power, current sharing DC/DC power module to power-hungry datacom, telecom, and FPGA applications. All that is needed to have a complete, dual 15A design ready for use are the ISL8225M, a few passive components, and VOUT setting resistors. The simplicity of the ISL8225M is its off-the-shelf, unassisted implementation. Patented current sharing in multiphase operation greatly reduces ripple currents, BOM costs, and complexity. The ISL8225M has a thermally enhanced, compact 17mmx17mmx7.5mm QFN package that operates at full load and over-temperature without requiring forced-air cooling. Easy access to all pins, with few external components, reduces PCB design to a component layer and a simple ground layer. This ISL8225MEVAL4Z evaluation board is designed for dual 15A output applications. Optionally, this board can easily be converted for 30A single output use. Multiple ISL8225MEVAL4Z boards can be cascadable through the SYNC and CLKOUT pins to operate with phase shifting, for paralleling or multiple output use. The input voltage of this board is 4.5V to 20V and the default outputs on this board are set at 1.2V and 1.5V. Key Features • Full encapsulated dual step down switching power supply • Up to 100W output • Dual 15A or single 30A output • 4.5V to 20V input range • 0.6V to 7.5V output range • 1.5% output voltage accuracy • Up to 95% conversion efficiency Specifications This board is configured and optimized for the following operating conditions: • VIN = 4.5V to 20V, VO1 = 1.2V, VO2 = 1.5V • IO1 = 15A, IO2 = 15A • fSW = 500kHz Ordering information Part Number ISL8225MEVAL4Z Description Dual 15A/Optional 30A Cascadable Evaluation Board Related Literature For a full list of related documents, visit our website: • ISL8225M device page Related Resources • Evaluation Board Video AN1793 Rev.4.00 Jun.25.19 Page 2 of 15 ISL8225MEVAL4Z V VOUT2 + - + LOAD2 (0A~15A) 4.5V to 20V LOAD1 + (0A~15A) V VIN VOUT1 - V + Figure 1. ISL8225MEVAL4Z Board AN1793 Rev.4.00 Jun.25.19 Page 3 of 15 ISL8225MEVAL4Z 1. 1.1 1. Functional Description Functional Description Recommended Equipment • 0V to 20V power supply with at least 5A source current capability • Electronic load capable of sinking current up to 30A • Digital Multimeters (DMMs) • 100MHz quad-trace oscilloscope 1.2 High Output Voltage Operation The ISL8225MEVAL4Z is designed for output voltage below 5.5V. For an output voltage higher than 6V, see the “ISL8225M Design Guide Matrix” table in the ISL8225M datasheet for selections of output capacitors, input capacitors, and switching frequency. The maximum load capability of each phase is 10A for 6.5V output and 7A for 7.5V output. 1.3 Quick Start For dual output operation, the inputs are BA7 (VIN1), BA8 (GND), BA3 (VIN2), and BA4 (GND). The outputs are BA5 (VOUT1), BA6 (GND), BA1 (VOUT2), and BA2 (GND). For paralleled single output operation, the inputs are BA7 (VIN1) and BA8 (GND). The outputs are BA5 (VOUT1) and BA6 (GND) with BA5 and BA1 shorted. 1.3.1 Dual Output Mode 1. Connect a power supply capable of sourcing at least 5A to the inputs BA7 (VIN1), BA8 (GND), BA3 (VIN2), and BA4 (GND) of the ISL8225MEVAL4Z, with a voltage between 4.5V to 20V. VIN1 and VIN2 can be different with R18 and R19 open. 2. Connect an electronic load or the device to be powered to the outputs BA5 (VOUT1) and BA6 (GND), BA1 (VOUT2) and BA2 (GND) of the board. All connections, especially the low voltage, high current VOUT lines, should be able to carry the load current and should be made as short as possible. 3. Make sure that the setup is connected correctly. Turn on the power supply. If the board is working properly, the green LED illuminates; if not, the red LED illuminates (recheck the wire/jumper connections in this case). Measure the output voltages, which should be VOUT1 at 1.2V and VOUT2 at 1.5V 4. For different output voltages, board resistors can be exchanged to provide the needed VOUT. See Table 1 for R2/R4 resistor values, which can produce different output voltages. For 12V VIN and VOUT more than 1.5V, the switching frequency needs to be adjusted, as shown in Table 1. The resistor RFSET can be adjusted for the desired frequency. No frequency adjustments are necessary for VOUT below 1.5V. For 5V VIN, the frequency does not need to be adjusted and the module default frequency can be used at any allowed VOUT. If the output voltage is set to more than 1.8V, the output current needs to be derated to allow for safe operation. See the derating curves in the ISL8225M datasheet. Table 1. Value of Bottom Resistor (Top Resistor R1, R3 = 1kΩ) and Frequency Selection for Different Output Voltages VOUT (V) R2 /R4 (Ω) Frequency (kHz) RFSET (Ω) (VIN = 12V) 1.0 1500 DEFAULT OPEN 1.2 1000 DEFAULT OPEN 1.5 665 DEFAULT OPEN 2.5 316 650 249k 3.3 221 800 124k 5.0 137 950 82.5k 5.5 121 950 82.5k AN1793 Rev.4.00 Jun.25.19 Page 4 of 15 ISL8225MEVAL4Z Table 1. 1.3.2 1. Functional Description Value of Bottom Resistor (Top Resistor R1, R3 = 1kΩ) and Frequency Selection for Different Output Voltages (Continued) VOUT (V) R2 /R4 (Ω) Frequency (kHz) RFSET (Ω) (VIN = 12V) 6.5 102 750 147k 7.5 86.6 750 147k Optional Paralleled Single Output Mode 1. To set up the parallel mode, short JP1 (ENC), JP2 (VMON), and JP3 (COMP) with a jumper. To set up 180° interleaving phase between two channels, short the MODE pin and GND pin of JP6 with a jumper. 2. Remove R9 and R13. Change R14 to 0Ω. Change R18 and R19 to 0Ω. Short VOUT1 to VOUT2 using short wires or copper straps. Add C2 for a 470pF capacitor. 3. Connect a power supply capable of sourcing at least 5A to the ISL8225MEVAL4Z's inputs, BA7 (VIN1), BA8 (GND), BA3 (VIN2), and BA4 (GND), with a voltage between 4.5V to 20V. VIN1 and VIN2 need to be shorted together. 4. Connect an electronic load or the device to be powered to the board’s outputs, BA5 (VOUT1) and BA6 (GND). All connections, especially the low voltage, high current VOUT lines, should be able to carry the load current and should be made as short as possible. 5. Make sure the setup is connected correctly prior to applying any power to the board. Adjust the power supply to 12V and turn on the input power supply. If the board is working properly, the green LED illuminates; if not, the red LED illuminates (recheck the wire/jumper connections in this case). Measure the output voltages, VOUT1, which should be at 1.2V. 6. Apply any load that is less than 30A for normal steady state operation. See Table 1 to change the output voltage by changing resistor R2. Table 2. Board Configuration for Single Output 30A Application Dual Single 1.3.3 ENC VMON MODE COMP R9 R13 R14 OPEN OPEN OPEN OPEN 0 0 OPEN ON ON ON ON OPEN OPEN 0 Optional Cascadable Mode Cascadable mode is needed when multiple evaluation boards are used for paralleling or multiple output use. To evaluate the parallel features, Renesas recommends using the ISL8225MEVAL2Z 6-phase evaluation board for an easy and efficient setup (see AN1789 “ISL8225MEVAL2Z Evaluation Board User Guide”). Otherwise, complete the following steps: 1. To generate CLKOUT at a shifted phase clock signal, disable the control loop of VOUT2 by connecting VSEN2to VCC. 2. Program the MODE and VSEN2+ pin voltages to set the CLKOUT signal and the shifted degrees between two phases on the board (see Table 3 on page 6). 3. Use a coaxial cable to connect CLKOUT (J5) to SYNC (J2) of the next evaluation board, which can be programmed for parallel or dual output use. 4. If the second board is programed for parallel use, the ISHARE pins of the first and second boards need to be tied together. Using two twisted wires, short two different jumpers of JP7 (ISHARE/SGND) on two evaluation boards. Add 1nF capacitors of C14 for different boards to decouple the noise. 5. If the third board is used in cascadable mode, the second board can only be used in the parallel mode to generate the CLKOUT signal for the SYNC pin on the third board. 6. Follow the instructions from Steps 1 through 5 for more cascadable boards. AN1793 Rev.4.00 Jun.25.19 Page 5 of 15 ISL8225MEVAL4Z 2. 2. PCB Layout Guidelines PCB Layout Guidelines The evaluation board size is 114.3mmx76.2mm. It is a 4-layer board that contains 2-oz copper on all layers. The board can be used as a dual 15A reference design. See “ISL8225MEVAL4Z Board Layout” on page 9. The board is made of FR4 material and all components, including the solder attachment, are Pb-free. 2.1 Thermal Considerations and Current Derating For high current applications, board layout is very critical to make the module operate safely and deliver maximum allowable power. To carry large currents, the board layout needs to be designed carefully to maximize thermal performance. For best thermal performance, select enough trace width, copper weight, and the proper connectors. This evaluation board is designed for running dual 15A at room temperature without additional cooling systems needed. However, if the output voltage is increased or the board is operated at elevated temperatures, the available current is derated. See the derated current curves in the ISL8225M datasheet to determine the output current available. For layout of designs using the ISL8225M, the thermal performance can be improved by adhering to the following design tips: • Use the top and bottom layers to carry the large current. VOUT1, VOUT2, Phase 1, Phase 2, PGND, VIN1, and VIN2 should have large, solid planes. Place enough thermal vias to connect the power planes in different layers under and around the module. • The Phase 1 and Phase 2 pads are switching nodes that generate switching noise. Keep these pads under the module. For noise-sensitive applications, Renesas recommends keeping phase pads only on the top and inner layers of the PCB; do not place phase pads exposed to the outside on the bottom layer of the PCB. To improve the thermal performance, the phase pads can be extended in the inner layer, as shown in Phase 1 and Phase 2 pads on layer 2 (Figure 5 on page 9) for this dual 15A evaluation board. Make sure that layer 1 and layer 3 have the GND layers cover the extended areas of the phase pads at layer 2 to avoid noise coupling. • Place the modules evenly on the board and leave enough space between modules. If the board space is limited, try to put the modules with low power loss closely together (such as low VOUT or IOUT) while still separating the module with high power loss. • If the ambient temperature is high or the board space is limited, airflow is needed to dissipate more heat from the modules. A heatsink can also be applied to the top side of the module to further improve the thermal performance (heatsink recommendation: Aavid Thermalloy, part number 375424B00034G, www.aavid.com). Table 3. ISL8225M Operation Modes 1ST Module (I = Input; O = Output; I/O = Input and Output, Bi-Direction) EN1/ EN2/ FF1 FF2 (I) Mode (I) VSEN2(I) VMON1 CLKOUT of 2nd VMON2 /REFIN Module Mode VSEN2+ WRT 1st (Notes 2, (Notes 2, (I OR O) (I) (I) 3, 4) 3, 4) Modes of Operation 2nd Channel WRT 1st (O) (Note 1) Operation Operation Output Mode Mode (See of 3rd of 2nd Description Module For Details) Module 1 0 0 - - - - - - - - - Disabled 2A 0 1 Active Active Active - Active - VMON1 = VMON2 to Keep PGOOD Valid - - Single Phase 2B 1 0 - - - - - - VMON1 = VMON2 to Keep PGOOD Valid - - Single Phase 3A 1 1 Active 29% to 45% of VCC (I) Active - 0° - - Dual Regulator