USERS MANUAL ISL8271MEVAL1Z AN1925 Rev 1.00 Evaluation Board August 15, 2014 The ISL8271M is a 33A step-down DC/DC power supply Key Features module with integrated digital PWM controller, synchronous V range of 4.5V to 14V, V adjustable from 0.6V to 5V power switches, an inductor and passives. Only bulk input and IN OUT output capacitors are needed to finish the design. The 33A of Programmable V , margining, UV/OV, I limit, OUT OUT continuous output current can be delivered without a need of soft-start/stop, sequencing, and external synchronization airflow or a heatsink. The ISL8271M uses ChargeMode Monitor: V , V , I , temperature, duty cycle, switching IN OUT OUT control architecture, which responds to a transient load within frequency and faults a single switching cycle. ChargeMode control tunable with PMBus The ISL8271MEVAL1Z evaluation board is a 3inx4.5in 4-layer Mechanical switch for enable and power-good LED indicator FR4 board with 2 oz. in all layers. This evaluation board comes with a placeholder for pin-strap resistors to adjust output Recommended Equipment voltage, switching frequency, input undervoltage (UVLO) protection threshold, and device PMBus address. More DC power supply with minimum 15V/25A sourcing capacity configuration such as soft-start, and fault limits can be easily Electronic load capable of sinking current up to 33A programmed or changed via PMBus compliant serial bus Digital multimeters (DMMs) interface. Oscilloscope with higher than 100MHz bandwidth ZLUSBEVAL3Z (USB to PMBus adapter) is provided with this evaluation kit, which connects the evaluation board to a PC to Functional Description activate the PMBus communication interface. The PMBus command set is accessed by using the PowerNavigator The ISL8271MEVAL1Z provides all circuitry required to evaluation software from a PC running Microsoft Windows. evaluate the features of the ISL8271M. A majority of the features of the ISL8271M, such as compensation-free ChargeMode control, soft-start delay and ramp times, supply References sequencing, and voltage margining are available on this ISL8271M datasheet evaluation board. For sequencing evaluation, the board can be connected to any Intersil digital module evaluation board that Ordering Information supports the Digital-DC (DDC) bus. PART NUMBER DESCRIPTION Figure 1 shows a board image of the ISL8271MEVAL1Z ISL8271MEVAL1Z ISL8271M Kit (EVB, ZLUSBEVAL3Z Adapter, evaluation board. USB Cable) INTERCONNECTS DDC AND SYNC BETWEEN BOARDS PGOOD LED INTERCONNECTS DDC AND ENABLE SWITCH SYNC BETWEEN BOARDS CONNECT TO ZLUSBEVAL3Z DONGLE. FOR MULTIPLE TO DAISY CHAIN PMBus BOARD EVALUATION, CONNECTION CON-NECT TO PMBUS DONGLE OUT CONNECTION OF OTHER BOARD PLACEHOLDER FOR SMA CONNECTOR TO MONITOR V RIPPLE OUT FIGURE 1. ISL8271MEVAL1Z EVALUATION BOARD IMAGE AN1925 Rev 1.00 Page 1 of 10 August 15, 2014ISL8271MEVAL1Z 9. To change switching frequency, disconnect board from the Operation setup and populated 1% standard 0603 resistor at R2 PMBus Operation placeholder location on bottom layer. Refer to the Switching Frequency Resistor Settings table in the ISL8271M The ISL8271M utilizes the PMBus protocol. The PMBus datasheet for recommended values. functionality can be controlled via ZLUSBEVAL3Z dongle from a 10. To change UVLO, disconnect board from the setup and PC running the PowerNavigator evaluation software in a populated 1% standard 0603 resistor at R7 placeholder Windows XP or Windows 7 operating systems. location on bottom layer. Refer to the UVLO Resistor Settings Install the evaluation software from the following Intersil table in the ISL8271M datasheet for recommended values. website: www.intersil.com/powernavigator PMBus Option For board operation, connect the included ZLUSBEVAL3Z dongle ISL8271MEVAL1Z can be evaluated for all features using the to the 6-pin male connector labeled as PMBus DONGLE IN. provided ZLUSBEVAL3Z dongle and PowerNavigator evaluation Connect the desired load and an appropriate power supply to the software. Follow these steps to evaluate ISL8271M with PMBus input and connect the included USB cable to the PC running the option. PowerNavigator evaluation software. Place the ENABLE switches in DISABLE before turning on the power. 1. Install PowerNavigator software. The evaluation software allows modification of all ISL8271M 2. Set ENABLE switch to DISABLE. PMBus parameters. The ISL8271M device on the board has been 3. Connect Load to VOUT lug connectors (J7 and J8). pre-configured as described in this document, but the user may 4. Connect power supply to VIN connectors (J3 and J4). Make modify the operating parameters through the evaluation sure power supply is not enabled when making connection. software or by loading a predefined set-up from a configuration 5. Turn power supply on. file. A sample Configuration File on page 5 is provided and can 6. Connect ZLUSBEVAL3Z dongle (USB to PMBus adapter) to be copied to a notepad editor to make desired changes. ISL8271MEVAL1Z board to the 6-pin male connector labeled The ENABLE switch can then be moved to ENABLE and the as PMBus DONGLE IN. ISL8271MEVAL1Z board can be tested. Alternately, the PMBus 7. Connect supplied USB cable from computer to USB to ON OFF CONFIG and OPERATION commands may be used from ZLUSBEVAL3Z dongle. the PowerNavigator GUI. 8. Launch PowerNavigator software. 9. Set ENABLE switch to ENABLE. Quick Start Guide 10. Monitor and configure the ISL8271MEVAL1Z board using Pin-Strap Option PMBus commands in the evaluation software. The ISL8271MEVAL1Z can be configured in pin-strap mode with 11. PowerNavigator tutorial videos are available at Intersil standard 1% 0603 resistors. PMBus interface is not required to website. www.intersil.com/powernavigator evaluate ISL8271M in pin-strap mode. Output voltage (V ), OUT 12. For sequencing via Digital-DC Bus (DDC) or to evaluate switching frequency (F ), input undervoltage protection (UVLO) SW multiple Intersil digital power products using a single threshold and device PMBus address can be changed by ZLUSBEVAL3Z dongle, ISL8271M can be daisy chained with populating recommended resistors at placeholders provided in other digital power evaluation boards. PMBus address can be the evaluation board. By default, the evaluation board is changed by placing a 1% standard 0603 resistor at the R5 programmed to regulate at V = 1.2V, F = 533kHz, OUT SW placeholder location on the bottom layer. Refer to the SMBus UVLO = 4.5V, and PMBus address = 28h. Follow these steps to Address Resistor Selection table in the ISL8271M datasheet evaluate ISL8271M in pin-strap mode. for recommended values. 1. Set ENABLE switch to DISABLE. Thermal Considerations and 2. Connect Load to VOUT lug connectors (J7 and J8). Current Derating 3. Connect power supply to VIN connectors (J3 and J4). Make sure power supply is not enabled when making connection. Board layout is very critical in order to make the module operate safely and deliver maximum allowable power. To work in the high 4. Turn power supply on. temperature environments and carry large currents, the board 5. Set ENABLE switch to ENABLE. layout needs to be carefully designed to maximize thermal 6. Measure 1.2V VOUT at probe points (TP10 and TP11) performance. To achieve this, select enough trace width, copper weight and the proper connectors. 7. Observe switching frequency of 533kHz at probe point labeled VSWH (TP1). The ISL8271MEVAL1Z evaluation board is designed for running 8. To change VOUT, disconnect board from the set up and 33A at room temperature without additional cooling systems populated 1% standard 0603 resistor at R6 placeholder needed. However, if the output voltage is increased or the board location on bottom layer. Refer to the Output Voltage is operated at elevated temperatures, then the available current Resistor Settings table in the ISL8271M datasheet for is derated. Refer to the derated current curves in the ISL8271M recommended values. By default, VOUT MAX is set to 110% datasheet to determine the maximum output current the of VOUT set by the pin-strap resistor. evaluation board can supply. is measured by inserting JA thermocouple inside the module to measure peak junction temperature. AN1925 Rev 1.00 Page 2 of 10 August 15, 2014