Click here to ask about the production status of specific part numbers. Evaluates: MAX20472/MAX20472B MAX20472 Evaluation Kit General Description Quick Start The MAX20472 evaluation kit demonstrates the perfor- Required Equipment mance of the MAX20472 and MAX20472B, which is part MAX20472 EV kit of the MAX2047x series of high-efficiency, low-voltage 3.3V, 2A power supply DC-DC converters. The converter ICs boost a 3.0V to 4.0V input supply to between 3.8V and 5.25V at up to 1A. 5, 25W resistor or 1A electronic load The boost converters achieve 1.5% output error over Digital multimeter (DMM) load, line, and temperature range. Procedure The IC features a 2.2MHz (2.0MHz for the MAX20472B) The EV kit is fully assembled and tested. Follow the steps fixed-frequency forced-PWM (FPWM) mode for better below to verify board operation: noise immunity and load-transient response, and a pulse- frequency modulation mode (skip) for increased efficiency 1) Connect the 3.3V supply to the VSUP and GND PCB during light-load operation. The 2.2MHz or 2.0MHz fre- test loops. quency operation enables the use of all-ceramic capacitors 2) Remove the EN jumper. and minimizes external components. The programmable 3) Activate the supply. Use the DMM to verify that the spread-spectrum-frequency modulation minimizes radi- voltage at the supply is 3.3V, the output is 0V, and ated electromagnetic emissions. Integrated low R DS(ON) the RESET pin voltage is 0V. switches improve efficiency at heavy loads and make the 4) Place a jumper across pins 1-2 on the EN header. layout a much simpler task with respect to discrete solu- Use the DMM to verify that the voltage at the output tions. is 5.0V and the RESET pin is 3.3V. 5) Connect the load (either resistive or electronic) to The regulator includes True Shutdown, soft-start, over- OUT and GND. current, and overtemperature protections. 6) Use the DMM to verify output voltage is still 5.0V. Features 3.0V to 4.0V Operating Supply Voltage 3.8V to 5.25V Fixed Output 1A Output Version Populated Compatible with 500mA and 2A Output Versions Ordering Information appears at end of data sheet. 2.2MHz Operation for the MAX20472 2.0MHz Operation for the MAX20472B Feedback Injection Point-to-Test Stability Robust for the Automotive Environment Current Mode, Forced-PWM and Skip Operation Overtemperature and Short-Circuit Protection -40C to +125C Operating Range Proven PCB Layout Fully Assembled and Tested True Shutdown is a trademark of Maxim Integrated Products, Inc. 319-100183 Rev 2 12/20Evaluates: MAX20472/MAX20472B MAX20472 Evaluation Kit Spread Spectrum (SSEN) Detailed Description of Hardware The IC has the option to enable spread-spectrum switching The MAX20472 EV kit comes fully assembled and tested. to reduce EMI. Spread spectrum can be enabled by install- The IC populated on the EV kit determines the pack- ing a jumper between pins 1-2 on the SSEN header, or dis- age and the output current limit. Any of the ICs in the abled by installing a jumper between pins 2-3. With spread MAX2047x series of high-efficiency, low-voltage DC-DC spectrum enabled, the internal oscillator varies the internal converters can be tested on this EV kit. Changing the operating frequency by 3% relative to the internally gen- IC may also require changing the external components erated 2.2MHz or 2.0MHz (typ) operating frequency. This on the EV kit. Refer to the MAX20471/MAX20472/ function does not apply to an externally applied oscillation MAX20472B IC data sheet for guidance on selecting the frequency. The spread-spectrum frequency generated is proper components. pseudorandom, with a repeat rate well below the audio EV Kit Interface band. The VSUP and GND PCB pads provide power to the EV Fault Flag Signal (RESET) kit. Input capacitance is included to reduce peak currents The IC features an open-drain reset output for each drawn from the power source and reduces noise and volt- output that asserts low when the corresponding output age ripple on the input caused by the circuits switching. voltage is outside the undervoltage/overvoltage window. The regulator provides output power at the OUT and GND RESET remains asserted for a fixed timeout period after pins. Output capacitance is selected to ensure proper the output rises to its regulated voltage. The fixed timeout stability. period is 0.5ms by default, but can also be factory-set to The enable control input (EN) activates the IC channel 3.7ms, 7.4ms, or 14.8ms. To obtain a logic signal, place a from its low-power shutdown state. EN has an input pullup resistor between the RESET pin and VSUP. threshold of 1.0V (typ), with hysteresis of 80mV (typ). When an enable input goes high, the associated output PCB Layout Guidelines voltage ramps up with the programmed soft-start time. Proper PCB layout of the system is crucial to good perfor- The IC can be enabled either by installing a shunt/jumper mance. The loop area created by the DC-DC components across pins 1-2 on the EN header, or by applying a logic- must be minimized as much as possible. Place the input high signal to the EN PCB pad. To disable the IC, remove capacitor, power inductor, and output capacitor as close as the shunt on pins 1-2 and install a shunt across pins 2-3 possible to the IC package. The output capacitor experi- on the EN header, or apply a logic-low signal to the EN ences the greatest amount of ripple current, so should PCB pad. be placed closest to the IC. Increasing the loop area will increase EMI and switching jitter, but may also degrade Synchronization and Switching regulation and transient response. Optimal positioning and The IC has an on-chip oscillator that provides a 2.2MHz routing has been implemented on this EV kit. or 2.0MHz (typ) switching frequency. Depending on the condition of SYNC, two operation modes exist. If SYNC is unconnected or at GND, the IC operates in a highly efficient pulse-skipping mode if the load current is below Ordering Information the skip-mode current threshold. If the current is above PART TYPE the threshold, the IC automatically changes to FPWM MAX20472EVKIT EV Kit mode. If SYNC is at VSUP or has a frequency applied to Denotes RoHS compliance. it, the IC always operates in FPWM mode. The IC can be switched during operation between FPWM and skip mode by switching SYNC. SYNC can be connected to VSUP by installing a shunt across pins 1-2 on the SYNC header, or connected to GND by installing a shunt across pins 2-3 on the SYNC header. An external square wave can be applied to the SYNC test point to cause the converter to switch at the applied frequency (refer to the MAX20471/ MAX20472/MAX20472B IC data sheet for limits). Maxim Integrated 2 www.maximintegrated.com