Click here for production status of specific part numbers. Evaluates: MAX17242 MAX17242 Evaluation Kit with Preset 3.3V/2A Output Table 1. EN Configuration (JU1) General Description The MAX17242 evaluation kit (EV kit) demonstrates SHUNT EN PIN MODE the MAX17242 high-voltage, current-mode step-down POSITION converters with low operating current. The EV kit operates 1-2* Connected to SUP Normal Operation over a wide 3.5V to 36V input range and the output is set 2-3 Connected to PGND Shutdown Mode for 3.3V at 2A. The EV kit comes with the MAX17242ETPB installed. *Default position. Table 2. Operating-Mode and Frequency Features Control (JU2) Wide 3.5V to 36V Input Supply Range 96% Peak Efficiency at 3.5V Input in Skip Mode SHUNT FSYNC PIN MODE POSITION Forced-PWM or Skip-Mode Operation Programmable Switching Frequency (400kHz Default) 1-2* Connected to BIAS Forced-PWM mode Selectable Spread Spectrum Optimizes EMI Performance Connected to 2-3 Skip mode FSYNC Input and Power-Good Output AGND Proven 4-Layer 2oz Copper PCB Layout Connected to Forced-PWM mode Demonstrates 950mil x 835mil Solution Size Not installed FSYNC test point (device syncs to an and external clock external clock) Fully Assembled and Tested *Default position. Quick Start Table 3. Spread Spectrum (JU3) Required Equipment SHUNT MAX17242EV kit SPS PIN MODE POSITION 12V, 2A DC power supply Spread-Spectrum Electronic load capable of 2A 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 SHUNT POSITION MODE positions, as shown in Table 1 through Table 4. Installed* PGOOD pulled high to BIAS 2) Connect the power supply between the VINSUPSW and nearest PGND 2-hole pads or test points. Not installed PGOOD pulled high to V PULL 3) Connect the 2A electronic load between the VOUT and *Default position. nearest PGND 2-hole pads or test points. 4) Connect the DVM between the VOUT and nearest Ordering Information appears at end of data sheet. PGND test points. 5) Turn on the power supply. 6) Enable the electronic load. 7) Verify that the voltage at the VOUT test point is approximately 3.3V. 19-8459 Rev 3 5/18Evaluates: MAX17242 MAX17242 Evaluation Kit with Preset 3.3V/2A Output Power-Good Output (PGOOD) Detailed Description of Hardware The EV kit provides a PGOOD test point to monitor the The MAX17242EV kit demonstrates the MAX17242 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 3.3V deasserts when V drops below 92.5% of its regulation to 36V input range and the output is set for 3.3V at 2A. OUT voltage. R5 pulls PGOOD up to BIAS or V PULL with Consider thermal and switching efficiency when designing respect to AGND. When operating in Skip-mode, use an for operation in the 24V36V input voltage range. external voltage source for V PULL. Remove the shunt on Enable (EN) jumper JU4 and connect an external voltage source up to Place a shunt in the 1-2 position on JU1 for normal operation. 5.5V to the V PULL 2-hole pad. To place the device into shutdown mode, move the shunt Output on JU1 to the 2-3 position. Resistor R6 connects FB to BIAS for a fixed +3.3V (EV kit Synchronization Input (FSYNC) default output) or a fixed +5V output voltage. To set the The EV kit features jumper JU2 to control the synchro- output to other voltages between 1V and 10V, connect a nization input (FSYNC). The device synchronizes to an resistive divider from output (OUT) to FB to AGND. Use external signal applied to FSYNC. Connect FSYNC to the following equation to determine the R7 and R8 of the AGND to enable skip-mode operation. Connect to BIAS resistive divider network: to enable Forced-PWM mode, or to an external clock to V OUT enable fixed-frequency forced-PWM mode operation. R7=R81 V FB To use an external clock, uninstall the shunt on jumper JU2 where V = 1V and R8 is 500k. FB and apply the signal at the FSYNC test point and AGND. The external clock frequency at FSYNC can be higher or Operation at 1MHz Switching Frequency lower than the internal clock by 20%. Ensure that the duty For 1MHz switching frequency, the following components cycle of the external clock used has a minimum 100ns pulse must be changed to: width. The external clock logic High voltage can be in the in R4 = 27.4k the 1.4V5V range. L1 = 4.7H (recommend Coilcraft XAL6060-472MEB) Spread-Spectrum Option (SPS) R1 = 12.1k The EV kit provides jumper JU3 that allows SPS to be pulled high (BIAS) or pulled low (AGND). Connect SPS C10 = 6,800pF high to enable spread spectrum where the operating Additional capacitance on C8 may be needed, depending frequency is varied 3% centered on FOSC. Connect on transient performance. SPS low to disable the spread-spectrum feature. Setting the Switching Frequency (FOSC) The EV kit switches at 400kHz 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 MAX17242 IC data sheet for the correct R (R4) value. FOSC Maxim Integrated 2 www.maximintegrated.com