Evaluates: MAX20073 MAX20073 Evaluation Kit General Description Benefits and Features The MAX20073 evaluation kit demonstrates the 2.7V to 5.5V Input Voltage Range performance and behavior of the MAX20073, a part 0.5V to 3.8V Output Voltage Range in the MAX20015MAX20018/MAX20073/MAX20074 Set by External Resistive Divider or family of pin-compatible, low-voltage, step-down Preprogrammed at Factory switching regulator ICs. Base EV Kit Configuration Set to 1.8V/2A Output The regulator delivers current up to 2A at an output volt- High-Frequency Switching (2.2MHz) Allows for an age between 0.5V and 3.8V. The device operates from All-Ceramic Capacitor Design a 2.7V to 5.5V input supply voltage, making it ideal for Continuously Produces Output Current Up to 2A post-regulation and point-of-load applications. The total Compact Solution Size error over load, line, and temperature ranges is 1.5%. The base switching frequency is 2.2MHz, which allows for Externally Adjustable Output Implementation Fits all-ceramic capacitor application designs. The regulator 2 Inside 65mm Area can either be synchronized to an external clock or placed Preprogrammed Output Implementation Fits Inside in a power-saving skip mode for increased efficiency at 2 55mm Area light loads. Quick Start The regulator provides an enable input and fault Required Equipment flag output. The output voltage can be set using an external resistor-divider and an internal 0.5V MAX20073 EV kit reference. Alternatively, it can be programmed at the 5V, 2A power supply factory for a specific output voltage, achieving 1.5% Digital multimeter output accuracy without resorting to expensive 0.1% resistors. The soft-start time and fault hold time can also 0.9, 20W power resistor or 2A electronic load be factory programmed. Procedure The regulators include overtemperature shutdown and The EV kit is fully assembled and tested. Follow the steps overcurrent limiting. They are designed to continuously below to verify board operation: operate over the -40C to +125C ambient temperature. 1) Remove the jumper from JU1 (EN). Jumpers JU2 and JU3 can either be removed or populated. 2) Connect the power supply to VSUP and GND and activate the supply. 3) Use the multimeter to verify 5V input voltage and 0V output voltage. 4) Replace the jumper on JU1 (EN). 5) Use the multimeter to verify output voltage is 1.8V. 6) Connect load (either resistive or electronic) to VOUT Ordering Information appears at end of data sheet. and GND. 7) Use the multimeter to verify output voltage is still 1.8V. 19-8658 Rev 0 10/16Evaluates: MAX20073 MAX20073 Evaluation Kit Fault Flag Signal (RESET) Detailed Description of Hardware The device signals the presence/absence of fault condi- The MAX20073 EV kit is fully assembled and tested. tions through the RESET pin. An external pullup resistor The EV kit comes with the MAX20073ATBA/V+ installed. on the EV kit pulls the pin up to the supply voltage. The Other regulators in the family can be tested on the same pin has an open-drain configuration for the signal to inter- EV kit with IC replacement of U1. Changing either the IC face with other logic voltage levels. Under fault conditions, or the output configuration may also require changing the the open-drain FET closes and pulls the line down to external components. Refer to the MAX20073 IC data ground. Under normal conditions, the FET opens and the sheet for guidance on selecting the proper components. line is pulled up. EV Kit Interface PCB Layout Guidelines The VSUP and GND test points provide power to the EV Proper PCB layout of the system is crucial for good kit. Capacitor C7 emulates the output capacitance of a performance. The loop area created by the DC-DC compo- primary regulator feeding the EV kit. Additional capacitance nents must be minimized as much as possible. Place the can be connected across VSUP and GND, if desired. The PV (input) capacitor, power inductor, and output capacitor regulator provides output power at the OUT and GND pins. very close to the device. Increasing the loop area increases The standard 1.8V configuration requires only one output EMI and switching jitter, and can also degrade regula- capacitor, but additional capacitor lands are provided in tion and transient response. The optimal positioning and case lower output voltages are tested. routing for the three components is implemented on the EV The IC is enabled by populating a shunt across JU1 or kit and described below. applying a logic-high voltage at the EN test loop. The Place several vias in the exposed pad (EP) of the EN pin has a weak internal pulldown, so leaving the line device. Connect EP to ground, both on the outer disconnected causes the regulator to shut off. Upon layer and to all inner ground layers (using said vias). enabling, the output voltage ramps upwards from zero to A grid of small vias (2x3 grid of 0.010in diameter) is the target output over the soft-start time. recommended. Connecting EP to multiple ground layers Synchronization and Switching provides sufficient thermal sinking. The IC has the ability to operate in either forced-PWM A low-impedance ground connection to the device and (FPWM) mode or skip mode. Removing the jumper its associated components is critical. Use a size 1206 PV from JU2 causes the device to enter skip mode at low capacitor next to the device, directly adjacent to the PV output currents to boost efficiency (a weak internal pull- and GND pins. Route the LX trace out from the device, down on the SYNC pin causes the device to default to going underneath the PV capacitor, to the inductor. Place this mode when the SYNC pin is lotherwise left open). the output capacitor(s) GND pins next to the PV capaci- Populating a jumper on JU2 or applying a logic-high tor GND pin. The layer directly below the device and its signal to the SYNC pin causes the device to enter FPWM circuitry needs to be a large ground plane. Do not mode. Also, a square wave can be applied to the SYNC pin use separate analog and power grounds use a single to cause the device to switch at that frequency. common ground, as the high-frequency return current The MAX20073 can be programmed at the factory to out- flows on the ground plane directly below the associated put its switching frequency on the SYNC pin (the default components and traces and away from other circuitry. Use device populated on the EV kit does not behave in this several vias next to the capacitor and device GND pins manner). ICs configured this way always operate in FPWM for low-impedance connections to the ground plane (these mode. The square-wave output is offset 180 from the are in addition to the vias in the device EP mentioned devices switching behavior. previously). A spread-spectrum feature is available to reduce peak EMI emissions. Placing a jumper on JU3 activates spread Ordering Information spectrum on the power MOSFET switching frequency. Removing the jumper from JU3 changes back to fixed- PART TYPE frequency switching (the SSEN pin on the device has MAX20073EVKIT EV Kit a weak internal pulldown for a default state of spread spectrum deactivated if the pin is left open). Applying a Denotes RoHS compliant. square wave to the SYNC pin for synchronization overrides the spread-spectrum behavior. Maxim Integrated 2 www.maximintegrated.com