Evaluates: MAX20074 MAX20074 Evaluation Kit General Description Benefits and Features The MAX20074 evaluation kit demonstrates the 2.7V to 5.5V Input Voltage Range performance and behavior of the MAX20074, a part in 0.5V to 3.8V Output Voltage Range the MAX20015MAX20018/MAX20073/MAX20074 Set by External Resistive Divider or family of pin-compatible, low-voltage, step-down switching Preprogrammed at Factory regulator ICs. Base EV Kit Configuration Set to 1.8V/3A Output The regulator delivers current up to 3A at an output High-Frequency Switching (2.2MHz) Allows for an voltage 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 3A 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 MAX20074 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% resis- tors. The soft-start time and fault hold time can also be 0.6, 20W power resistor or 3A electronic load 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 range 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. 19-8659 Rev 0 10/16Evaluates: MAX20074 MAX20074 Evaluation Kit Fault Flag Signal (RESET) Detailed Description of Hardware The device signals the presence/absence of fault condi- The MAX20074 EV kit is fully assembled and tested. tions through the RESET pin. An external pullup resistor The EV kit comes with the MAX20074ATBA/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 face with other logic voltage levels. Under fault conditions, IC or the output configuration may also require changing the open-drain FET closes and pulls the line down to the external components. Consult the MAX20074 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 primary regulator feeding the EV kit. Additional components must be minimized as much as possible. capacitance can be connected across VSUP and GND, if Place the PV (input) capacitor, power inductor, and output desired. The regulator provides output power at the OUT capacitor very close to the device. Increasing the loop area and GND pins. The standard 1.8V configuration requires increases EMI and switching jitter, and can also degrade only one output capacitor, but additional capacitor lands regulation and transient response. The optimal positioning are provided in case lower output voltages are tested. and routing for the three components is implemented on The IC is enabled by populating a shunt across JU1 or the EV 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 device. Connect EP to ground, both on the outer layer line disconnected causes the regulator to shut off. Upon and to all inner ground layers (using said vias). A enabling, the output voltage ramps upwards from zero to 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 from JU2 causes the device to enter skip mode at low PV capacitor next to the device, directly adjacent to output currents to boost efficiency (a weak internal pull- the PV and GND pins. Route the LX trace out from down on the SYNC pin causes the device to default to the device, going underneath the PV capacitor, to the this mode when the SYNC pin is otherwise left open). inductor. Place the output capacitor(s) GND pins next to Populating a jumper on JU2 or applying a logic-high the PV capacitor GND pin. The layer directly below the signal to the SYNC pin causes the device to enter FPWM device and its circuitry needs to be a large ground plane. mode. Also, a square wave can be applied to the SYNC Do not use separate analog and power grounds use a pin to cause the device to switch at that frequency. single common ground, as the high-frequency return The MAX20074 can be programmed at the factory to current flows on the ground plane directly below the output its switching frequency on the SYNC pin (the associated components and traces and away from other default device populated on the EV kit does not behave in circuitry. Use several vias next to the capacitor and device this manner). ICs configured this way always operate in GND pins for low-impedance connections to the ground FPWM mode. The square-wave output is offset 180 from plane (these are in addition to the vias in the device EP the devices switching behavior. mentioned 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. PART TYPE Removing the jumper from JU3 changes back to fixed- frequency switching (the SSEN pin on the device has MAX20074EVKIT EV Kit a weak internal pulldown for a default state of spread Denotes RoHS compliant. spectrum or deactivated if the pin is left open). Applying a square wave to the SYNC pin for synchronization over- rides the spread-spectrum behavior. Maxim Integrated 2 www.maximintegrated.com