Click here for production status of specific part numbers. Evaluates: MAX20077/MAX25277 MAX20077 Evaluation Kit General Description Quick Start The MAX20077 evaluation kit (EV kit) provides a Required Equipment proven design to evaluate the MAX20077/MAX25277 MAX20077 EV kit 2.1MHz/400kHz high-voltage mini-buck converter in a Power supply 12-pin side-wettable TDFN package. All components are rated for the automotive temperature range. Various test Voltmeter points and jumpers are included for evaluation. Electronic load The standard EV kit comes with the MAX20077ATCA/VY+ Procedure installed (5V, 2.1MHz), but it can also be used to evaluate The EV kit is fully assembled and tested. Follow the steps other MAX20077/MAX25277 variants with minimal compo- below to verify board operation: nent changes (e.g., IC replacement of U1). 1) Verify that all jumpers are in their default positions, as Benefits and Features shown in Table 1. 3.5V to 36V Input Supply Range 2) Connect the positive and negative terminals of the power supply to the SUP and GND test pads, 5V or 3.3V Fixed Output Voltage, or Adjustable respectively. Between 1V and 10V 3) Connect the positive terminal of the voltmeter to OUT Delivers Up to 2.5A Output Current and the negative terminal to GND2. Frequency-Synchronization Input 4) Set the power supply to 14V and 2A current limit. Turn on the power supply. Enable Input 5) With the PU and LED headers shorted, the green Voltage-Monitoring PGOOD Output LED lights up. The voltmeter should display an output Proven PCB Layout voltage of 5V. Fully Assembled and Tested Ordering Information appears at end of data sheet. 319-100155 Rev 2 2/19Evaluates: MAX20077/MAX25277 MAX20077 Evaluation Kit Table 1. Default Jumper Settings JUMPER SHUNT POSITION FUNCTION EN ON-Middle Buck controller enabled SPS Middle-OFF Spread spectrum disabled PU, LED Installed PGOOD is pulled up by V when OUT is in regulation BIAS SYNC Middle-FPWM Forced-PWM mode variants can be installed and tested with minimal compo- Detailed Description nent changes. For the 2.1MHz variants, install the appro- The MAX20077 EV kit provides a proven layout for evalu- priate IC on the EV kit (U1), while keeping all other com- ating all variants of the MAX20077/MAX25277 family of ponents the same. For 400kHz parts, the inductor should small, current-mode-controlled buck converter ICs. Each be increased to 10H, and the output capacitance must device accepts input voltages as high as 36V and deliv- be a minimum 44F after derating is accounted for. For ers up to 2.5A. The EV kit can handle an input-supply MAX20077ATCE2 and MAX20077ATCD2 high-bandwidth transient up to 40V. parts, increase the output capacitance as per the guide- Switching Frequency and External lines in the IC datasheet. Synchronization The MAX20077ATCC/VY+ can be installed for output The ICs can operate in two modes, forced-PWM or skip. voltages between 1V and 3V (2.1MHz). The inductor Skip mode has better efficiency for light-load conditions. should be set to 4.7H, and the output capacitance must When SYNC is pulled low, the device operates in skip be a minimum 44F after derating is accounted for. The mode for light loads, and in PWM mode for larger loads. output voltage must be externally adjusted. When SYNC is pulled high, the device is forced to operate Setting the Output Voltage in the in PWM across all load conditions. Buck Converters SYNC can be used to synchronize with other supplies if a To externally adjust the output voltage, remove R1 and clock source is present. The device is forced to operate in install a 0 resistor on R4. Place appropriate resistors in PWM when SYNC is connected to a clock source. positions R5 and R6 according to the following equation: Buck Output Monitoring (PGOOD) V OUT The EV kit provides a power-good output test point R5 R6 1 V FB (PGOOD) to monitor the status of the buck output (OUT). PGOOD is low impedance when the output voltage is in where V = 1V (typ) and R6 = 50k. FB regulation. PGOOD is high impedance when the output voltage drops below 8% (typ) of its nominal regulated voltage. To obtain a logic signal, pull up PGOOD to V by BIAS Ordering Information installing shunts on jumpers PU and LED. PART TYPE Evaluating Other Variants MAX20077EVKIT 5V output, 2.1MHz EV kit The EV kit comes installed with the fixed-output, 5V/2.1MHz Denotes RoHS compliant. variant (MAX20077ATCA/VY+) The 2.1MHz and 400kHz Maxim Integrated 2 www.maximintegrated.com =