USERS MANUAL ISL8117EVAL1Z UG030 Rev 0.00 Evaluation Board User Guide May 20, 2015 Description Key Features The ISL8117EVAL1Z evaluation board (shown in Figure 1) Small, compact design features the ISL8117. The ISL8117 is a 60V high voltage Wide input range: 4.5V 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 ISL8117EVAL1Z evaluation board is designed for high current applications. The current rating of the ISL8117EVAL1Z References is limited by the FETs and inductor selected. The electrical ISL8117 datasheet ratings of ISL8117EVAL1Z are shown in Table 1. TABLE 1. ELECTRICAL RATINGS Ordering Information PARAMETER RATING Input Voltage 4.5V to 60V PART NUMBER DESCRIPTION Switching Frequency 600kHz ISL8117EVAL1Z High Voltage PWM Step-down Synchronous Buck Controller Output Voltage 3.3V Output Current 6A OCP Set Point Minimum 8A at ambient room temperature FIGURE 1. ISL8117EVAL1Z TOP SIDE FIGURE 2. ISL8117EVAL1Z BOTTOM SIDE UG030 Rev 0.00 Page 1 of 11 May 20, 2015ISL8117EVAL1Z Recommended Testing Functional Description Equipment The ISL8117EVAL1Z is a compact design with high efficiency and high power density. The following materials are recommended to perform testing: As shown in Figure 4 on page 3, 4.5V to 60V V is supplied to J1 IN 0V to 60V power supply with at least 10A source current (+) and J2 (-). The regulated 12V output on J3 (+) and J5 (-) can capability supply up to 6A to the load. Electronic loads capable of sinking current up to 10A As shown in Table 2, connector J7 provides selection of either Digital Multimeters (DMMs) CCM mode (shorting pin 1 and pin 2) or DEM mode (shorting pin 2 and pin 3). Connector J6 provides an option to disable the 100MHz quad-trace oscilloscope converter by shorting its pin 1 and pin 2. Quick Test Guide Operating Range 1. Jumper J7 provides the option to select CCM or DEM. Please The input voltage range is from 4.5V to 60V for an output voltage refer to Table 2 for the desired operating option. Ensure that of 3.3V. The rated load current is 6A with the OCP point set at the circuit is correctly connected to the supply and electronic minimum 8A at room temperature ambient conditions. for loads prior to applying any power. Please refer to Figure 4 The temperature operating range of ISL8117 is -40C to proper setup. +125C. Please note that airflow is needed for higher 2. Turn on the power supply. temperature ambient conditions. 3. Adjust input voltage V within the specified range and IN observe output voltage. The output voltage variation should PCB Layout Guidelines be within 3%. Careful attention to layout requirements is necessary for 4. Adjust load current within the specified range and observe successful implementation of an ISL8117 based DC/DC output voltage. The output voltage variation should be converter. The ISL8117 switches at a very high frequency and within 3%. therefore the switching times are very short. At these switching 5. Use an oscilloscope to observe output voltage ripple and frequencies, even the shortest trace has significant impedance. phase node ringing. For accurate measurement, please refer Also, the peak gate drive current rises significantly in an to Figure 3 for proper test setup. extremely short time. Transition speed of the current from one device to another causes voltage spikes across the TABLE 2. OPERATING OPTIONS interconnecting impedances and parasitic circuit elements. JUMPER POSITION FUNCTION These voltage spikes can degrade efficiency, generate EMI, and increase device overvoltage stress and ringing. Careful J7 CCM (pins 1-2) Continuous current mode component selection and proper PC board layout minimizes the DEM (pins 2-3) Diode emulation mode magnitude of these voltage spikes. J6 (Pins 1-2) Disable the PWM There are three sets of critical components in a DC/DC converter using the ISL8117: the controller, the switching power components and the small signal components. The switching power components are the most critical from a layout point of view because they switch a large amount of energy, which tends to generate a large amount of noise. The critical small signal components are those connected to sensitive nodes or those OUTPUT CAP OUTOUTPPUTUT CAP CAP supplying critical bias currents. A multilayer printed circuit board OR MOSFET OR OR MMOSFOSFEETT is recommended. FIGURE 3. PROPER PROBE SETUP TO MEASURE OUTPUT RIPPLE AND PHASE NODE RINGING UG030 Rev 0.00 Page 2 of 11 May 20, 2015