Evaluates: MAX17243 MAX17243 Evaluation Kit with Preset 5V/3A Output Table 1. EN Configuration (JU1) General Description The MAX17243 evaluation kit (EV kit) demonstrates the SHUNT EN PIN MODE MAX17243 high-voltage, current-mode step-down con- POSITION verters with low operating current. The EV kit operates 1-2* Connected to SUP Normal Operation over a wide 5.6V to 36V input range and the output is set 2-3 Connected to PGND Shutdown Mode for 5V at 3A. The EV kit comes with the MAX17243ATPA/V+ installed. *Default position. Table 2. Operating-Mode and Frequency Features Control (JU2) Wide 5.6V to 36V Input Supply Range SHUNT Forced-PWM or Skip-Mode Operation FSYNC PIN MODE POSITION Programmable Switching Frequency (2.2MHz Default) 1-2* Connected to BIAS Forced-PWM mode Power-Good Output Connected to 4-Layer 2oz Copper 2-3 Skip mode AGND Proven PCB Layout Forced-PWM mode Not Connected to an Fully Assembled and Tested (device syncs to an installed** external clock external clock) Ordering Information appears at end of data sheet. *Default position. Quick Start Table 3. Spread Spectrum (JU3) Required Equipment SHUNT MAX17243EV kit SPS PIN MODE POSITION 14V, 2A DC power supply Spread-Spectrum Electronic load capable of 3A 1-2* Connected to BIAS Enabled Digital voltmeter (DVM) Connected to Spread-Spectrum Procedure 2-3 AGND Disabled The EV kit is fully assembled and tested. Follow the steps *Default position. below to verify board operation. Caution: Do not turn on supplies until all connections are made. Table 4. PGOOD (JU4) 1) Verify that jumpers JU1JU4 are in their default posi- SHUNT POSITION MODE tions, as shown in Tables 14. Installed* PGOOD pulled high to BIAS 2) Connect the power supply between the VINSUPSW and nearest PGND test points. Not installed PGOOD unconnected 3) Connect the 3A electronic load between the OUT and *Default position. nearest PGND test points. 4) Connect the DVM between the OUT and nearest PGND test points. 5) Turn on the power supply. 6) Enable the electronic load. 7) Verify that the voltage at the OUT test point is approxi- mately 5V. 19-7771 Rev 0 8/16Evaluates: MAX17243 MAX17243 Evaluation Kit with Preset 5V/3A Output Power-Good Output (PGOOD) Detailed Description of Hardware The EV kit provides a PGOOD test point to monitor the The MAX17243EV kit demonstrates the MAX17243 high- status of the device output. PGOOD asserts when V voltage, high-frequency, step-down converter with low OUT rises above 95% of its regulation voltage. PGOOD operating current. The EV kit operates over a wide 5.6V deasserts when V drops below 92.5% of its regulation to 36V input range and the output is set for 5V at 3A. For OUT voltage. R5 pulls PGOOD up to BIAS with respect to 24V to 36V operation forced air cooling must be used. AGND. Consider thermal and switching efficiency when designing for operation in this input voltage range. Output Enable (EN) Resistor R6 connects FB to BIAS for a fixed +5V (EV kit default output) or a fixed +3.3V output voltage. To set the Place a shunt in the 1-2 position on JU1 for normal operation. output to other voltages between 1V and 10V, connect a To place the device into shutdown mode, move the shunt resistive divider from output (OUT) to FB to AGND. Use on JU1 to the 2-3 position. the following equation to determine the R7 and R8 of the Synchronization Input (FSYNC) resistive divider network: The EV kit features JU2 to control the synchronization V OUT input (FSYNC). The device synchronizes to an external R7=R81 V signal applied to FSYNC. Connect FSYNC to AGND to FB enable skip-mode operation. Connect to BIAS or to an where V = 1V and R8 is 500k. FB external clock to enable fixed-frequency forced-PWM Operation at 400kHz Switching Frequency mode operation. For 400kHz switching frequency, the following components To use an external clock, uninstall the shunt on JU2 and must be changed to: apply the signal at the FSYNC test point and AGND. The R4 = 73.2k external clock frequency at FSYNC can be higher or lower than the internal clock by 20%. Ensure that the duty cycle of L1 = 6.8H (recommend Coilcraft XAL5050-682MEB) the external clock used has a minimum 100ns pulse width. R1 = 16.5k Spread-Spectrum Option (SPS) C10 = 4,700pF The EV kit provides JU3 that allows SPS to be pulled C11 = 6.8pF high (BIAS) or pulled low (AGND). Connect SPS Additional capacitance on C7 and C8 may be needed, high to enable spread spectrum where the operating depending on transient performance. frequency is varied 3% centered on FOSC. Connect SPS low to disable the spread-spectrum feature. Setting the Switching Frequency (FOSC) The EV kit switches at 2.2MHz by default, and the switching frequency is set by a resistor, R (R4), connected from FOSC F to AGND. Refer to TOC08 in the Typical Operating OSC Characteristics section of the MAX17243 IC data sheet for the correct R (R4) value. FOSC Maxim Integrated 2 www.maximintegrated.com