USERS MANUAL ISL8117AEVAL2Z UG050 Rev 0.00 Evaluation Board User Guide September 2, 2015 Description Key Features The ISL8117AEVAL2Z evaluation board (shown in Figure 4) Small, compact design features the ISL8117A. The ISL8117A 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 ISL8117AEVAL2Z evaluation board is designed for high current applications. The current rating of the ISL8117AEVAL2Z References is limited by the FETs and inductor selected. The electrical ISL8117A datasheet ratings of ISL8117AEVAL2Z are shown in Table 1. TABLE 1. ELECTRICAL RATINGS Ordering Information PARAMETER RATING Input Voltage 4.5V to 60V PART NUMBER DESCRIPTION Switching Frequency 300kHz ISL8117AEVAL2Z High voltage PWM step-down synchronous buck controller Output Voltage 3.3V Output Current 6A OCP Set Point Minimum 8A at ambient room temperature VIN VOUT UGATE LGATE/OCS ISL8117A EN MOD/SYNC VCC5C DISABLE CCM DEM FIGURE 1. ISL8117AEVAL2Z BLOCK DIAGRAM UG050 Rev 0.00 Page 1 of 11 September 2, 2015ISL8117AEVAL2Z Recommended Testing Operating Range Equipment The input voltage range is from 4.5V to 60V for an output voltage of 3.3V. The rated load current is 6A with the OCP point set at The following materials are recommended to perform testing: minimum 8A at room temperature ambient conditions. 0V to 60V power supply with at least 10A source current The temperature operating range of ISL8117A is -40C to capability +125C. Please note that airflow is needed for higher Electronic loads capable of sinking current up to 10A temperature ambient conditions. Digital Multimeters (DMMs) Evaluating the Other Output 100MHz quad-trace oscilloscope Voltages Quick Test Guide The ISL8117AEVAL2Z kit output is preset to 3.3V, however, the output can be adjusted from 1.8V to 5V. The output voltage 1. Jumper J5 provides the option to select CCM or DEM. Please programming resistor, R , will depend on the desired output 2 refer to Table 2 for the desired operating option. Ensure that voltage of the regulator and the value of the feedback resistor the circuit is correctly connected to the supply and electronic R , as shown in Equation 1. 1 for loads prior to applying any power. Please refer to Figure 3 proper setup. 0.6 (EQ. 1) ------------------------------ R = R 2 1 V 0.6 2. Turn on the power supply. OUT 3. Adjust input voltage V within the specified range and IN Table 3 shows the component selection that should be used for observe output voltage. The output voltage variation should the respective V of 1.8V, 3.3V and 5V. OUT be within 3%. TABLE 3. EXTERNAL COMPONENT SELECTION 4. Adjust load current within the specified range and observe output voltage. The output voltage variation should be V R OUT 2 within 3%. (V) (k ) 5. Use an oscilloscope to observe output voltage ripple and 1.8 24.9 phase node ringing. For accurate measurement, please refer 3.3 11 to Figure 2 for proper test setup. 56.8 TABLE 2. OPERATING OPTIONS JUMPER POSITION FUNCTION PCB Layout Guidelines J5 CCM (pins 1-2) Continuous current mode DEM (pins 2-3) Diode emulation mode Careful attention to layout requirements is necessary for successful implementation of an ISL8117A based DC/DC J6 (Pins 1-2) Disable the PWM converter. The ISL8117A switches at a very high frequency and therefore the switching times are very short. At these switching frequencies, even the shortest trace has significant impedance. Also, the peak gate drive current rises significantly in an extremely short time. Transition speed of the current from one device to another causes voltage spikes across the interconnecting impedances and parasitic circuit elements. OUTPUT CAP OUTOUTPPUTUT CAP CAP These voltage spikes can degrade efficiency, generate EMI, and OR MOSFET OR OR MMOSFOSFEETT increase device overvoltage stress and ringing. Careful component selection and proper PC board layout minimizes the FIGURE 2. PROPER PROBE SETUP TO MEASURE OUTPUT RIPPLE magnitude of these voltage spikes. AND PHASE NODE RINGING There are three sets of critical components in a DC/DC converter Functional Description using the ISL8117A: The ISL8117AEVAL2Z is a compact design with high efficiency The controller and high power density. The switching power components As shown in Figure 3 on page 3, 4.5V to 60V V is supplied to J1 IN The small signal components. (+) and J7 (-). The regulated 3.3V output on J8 (+) and J9 (-) can The switching power components are the most critical from a supply up to 6A to the load. layout point of view because they switch a large amount of As shown in Table 2, connector J5 provides selection of either energy, which tends to generate a large amount of noise. The CCM mode (shorting pin 1 and pin 2) or DEM mode (shorting critical small signal components are those connected to sensitive pin 2 and pin 3). Connector J6 provides an option to disable the nodes or those supplying critical bias currents. A multilayer converter by shorting its pin 1 and pin 2. printed circuit board is recommended. UG050 Rev 0.00 Page 2 of 11 September 2, 2015