USERS MANUAL ISL8117DEMO2Z UG021 Rev 0.00 Demonstration Board User Guide April 20, 2015 Description Key Features The ISL8117DEMO2Z demonstration board (shown in Figure 1) Small, compact design features the ISL8117. The ISL8117 is a 60V high voltage Wide input range: 18V to 60V synchronous buck controller that offers external soft-start, High light-load efficiency in pulse skipping DEM operation independent enable functions and integrates UV/OV/OC/OT protection. Its current mode control architecture and internal Programmable soft-start compensation network keep peripheral component count Optional DEM/CCM operation minimal. Programmable switching frequency ranging from Supports prebias output with SR soft-start 100kHz to 2MHz helps to optimize inductor size while the strong gate driver delivers up to 30A for the buck output. External frequency sync PGOOD indicator Specifications OCP, OVP, OTP, UVP protection The ISL8117DEMO2Z demonstration board is designed for high current applications. The current rating of the References ISL8117DEMO2Z is limited by the FETs and inductor selected. The ISL8117 datasheet The ISL8117 gate driver is capable of delivering up to 20A for the buck output as long as the proper FETs and inductor are provided. The electrical ratings of ISL8117DEMO2Z are shown Ordering Information in Table 1. PART NUMBER DESCRIPTION TABLE 1. ELECTRICAL RATINGS ISL8117DEMO2Z High Voltage PWM Step-Down PARAMETER RATING Synchronous Buck Controller Input Voltage 18V to 60V Switching Frequency 200kHz Recommended Testing Output Voltage 12V Equipment Output Current 20A The following materials are recommended to perform testing: OCP Set Point Minimum 25A at ambient room temperature 0V to 60V power supply with at least 30A source current capability Electronic loads capable of sinking current up to 30A Digital Multimeters (DMMs) 100MHz quad-trace oscilloscope FIGURE 1. ISL8117DEMO2Z DEMONSTRATION BOARD TOP FIGURE 2. ISL8117DEMO2Z DEMONSTRATION BOARD BOTTOM UG021 Rev 0.00 Page 1 of 13 April 20, 2015ISL8117DEMO2Z The rated load current is 20A with the OCP point set at minimum Quick Test Guide 25A at room temperature ambient conditions. 1. Jumper J5 provides the option to select CCM or DEM. Please The temperature operating range is -40C to +125C. for the desired operating option. Ensure that refer to Table 2 Please note that air flow is needed for higher temperature the circuit is correctly connected to the supply and electronic ambient conditions. loads prior to applying any power. Please refer to Figure 4 for proper set-up. Evaluating the Other Output 2. Turn on the power supply. Voltages 3. Adjust input voltage V within the specified range and IN observe output voltage. The output voltage variation should The ISL8117DEMO2Z kit output is preset to 12V, however, the be within 3%. output can be adjusted from 5V to 24V. The output voltage 4. Adjust load current within the specified range and observe programming resistor, R , will depend on the desired output 2 output voltage. The output voltage variation should be voltage of the regulator and the value of the feedback resistor within 3%. R , as shown in Equation 1. 1 5. Use an oscilloscope to observe output voltage ripple and 0.6 (EQ. 1) ------------------------------ R = R phase node ringing. For accurate measurement, please refer 2 1 V 0.6 OUT to Figure 3 for proper test set-up. Table 3 shows the component selection that should be used for TABLE 2. the respective V of 5V, 12V and 24V. OUT JUMPER POSITION FUNCTION TABLE 3. EXTERNAL COMPONENT SELECTION J5 CCM (pins 1-2) Continuous current mode V MAX IN DEM (pins 2-3) Diode emulation mode V R R R L C RANGE I OUT 2 4 7 1 6 OUT J6 (Pins 1-2) Disable the PWM 5V 5.9k 36k 7.5k IHLP6767GZER3R3M11, 150pF 8V~60V 20A 3.3H/35A 12V 2.26k 90.9k 7.5k IHLP6767GZER5R6M11, 220pF 18V~60V 20A 5.6H/28A 24V 1.1k 150k 3.3k IHLP6767GZER100M11, 470pF 28V~60V 10A 10H/19A OUTPUT CAP OUTOUTPPUTUT CAP CAP OR MOSFET OR OR MMOSFOSFEETT Layout Guidelines Careful attention to layout requirements is necessary for successful implementation of an ISL8117 based DC/DC FIGURE 3. PROPER PROBE SET-UP TO MEASURE OUTPUT RIPPLE converter. The ISL8117 switches at a very high frequency and AND PHASE NODE RINGING therefore the switching times are very short. At these switching frequencies, even the shortest trace has significant impedance. Functional Description Also, the peak gate drive current rises significantly in an The ISL8117DEMO2Z is a compact design with high efficiency extremely short time. Transition speed of the current from one and high power density. device to another causes voltage spikes across the interconnecting impedances and parasitic circuit elements. As shown in Figure 4 on page 3, 18V to 60V V is supplied to J1 IN These voltage spikes can degrade efficiency, generate EMI and (+) and J2 (-). The regulated 12V output on J3 (+) and J4 (-) can increase device overvoltage stress and ringing. Careful supply up to 20A to the load. Due to high thermal efficiency, the component selection and proper PC board layout minimizes the demonstration board can run at 20A continuously without air magnitude of these voltage spikes. flow in room temperature ambient condition. There are three sets of critical components in a DC/DC converter As shown in Table 2, connector J5 provides selection of either using the ISL8117: the controller, the switching power CCM mode (shorting pin 1 and pin 2) or DEM mode (shorting components and the small signal components. The switching pin 2 and pin 3). Connector J6 provides an option to disable the power components are the most critical from a layout point of converter by shorting its pin 1 and pin 2. view because they switch a large amount of energy which tends to generate a large amount of noise. The critical small signal Operating Range components are those connected to sensitive nodes or those supplying critical bias currents. A multilayer printed circuit board The input voltage range is from 18V to 60V for an output voltage is recommended. of 12V. If the output voltage is set to a lower value, the minimum V can be reset to a lower value by changing the ratio of R and IN 4 R . The minimum EN threshold that V can be set to is 4.5V. 5 IN UG021 Rev 0.00 Page 2 of 13 April 20, 2015