MAX20003EVKIT# Analog Devices

Evaluates: MAX20002/MAX20003 MAX20003 Evaluation Kit Table 1. EN Configuration (JU1) General Description The MAX20003 evaluation kit (EV kit) demonstrates the SHUNT DESCRIPTION MAX20002/MAX20003 high-voltage, current-mode step- POSITION down converters with low operating current. The EV kit Connects the EN pin to the voltage at SUP operates over a wide 3.5V to 36V input range and the 1-2* for normal operation output is set for 5V at 3A. Connects the EN pin to ground to enter The EV kit comes with the MAX20003ATPA/V+ installed. 2-3 shutdown mode Features and Benefits *Default position. Wide 3.5V to 36V Input Supply Range Table 2. Mode of Operation (JU2) Forced-PWM or Skip-Mode Operation SHUNT Programmable Switching Frequency MODE PIN MODE POSITION Power-Good Output 1-2* Connected to BIAS Forced-PWM mode Proven PCB Layout Connected to 2-3 Skip mode Fully Assembled and Tested AGND Forced-PWM mode Ordering Information appears at end of data sheet. Connected to an Not installed (device syncs to an external clock external clock) *Default position. Quick Start Required Equipment Table 3. Spread Spectrum (JU3) MAX20003 EV kit SHUNT 14V, 2A DC power supply MODE PIN MODE POSITION Electronic load capable of 3A Spread-spectrum 1-2* Connected to BIAS Digital voltmeter (DVM) enabled Connected to Spread-spectrum Procedure 2-3 PGND 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 JU1JU 4 are in their default posi- tions, as shown in Tables 14. SHUNT POSITION MODE 2) Conn ect the power supply between the SUPSW and Installed PGOOD pulled high to VL nearest PGND test points. Not installed PGOOD unconnected 3) Conn ect the 3A electronic load between the OUT and nearest PGND test points. 6) Enable the electronic load. 4) Conn ect the DVM betwee n the OUT and nearest PGND test poin ts. 7) Verify that the voltage at the OUT test point is approxi- mately 5V. 5) Turn on the power supply. 19-7413 Rev 0 5/14Evaluates: MAX20002/MAX20003 MAX20003 Evaluation Kit Power-Good Output (PGOOD) Detailed Description of Hardware The EV kit provides a PGOOD test point to monitor the The MAX20003 EV kit demonstrates the MAX20003 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 3.5V to deasserts when V drops below 92.5% of its regulation 36V input range and the output is set for 5V at 3A. OUT voltage. Enable (EN) Output Place a shunt in the 1-2 positio n on jumper JU1 for normal Connect FB to BIAS for a fixed +5V (EV kit default operation. To place the device into shutdown mode, move output) or a fixed +3.3V output voltage. To set the output the shunt on JU1 to the 2-3 position. to other voltage s between 1V and 10V, connect a resistive Synchronization Input (FSYNC) divider from output (OUT) to FB to AGND. Use the follow- The EV kit features jumper JU2 to control the synchro- ing formula to determine the R7 and R8 of the resistive nization input (FSYNC). The device synchronizes to an divider network: external signal applied to FSYNC. Connect FSYNC to V OUT AGND to enabl e skip-mode operation. Connect to BIAS R7=R8 1 V or to an external clock to enab le fixed-frequency forced- FB PWM mode operation. where V = 1V. FB To use an external clock, unin stall the shunt on JU2 and Operation at 400kHz Switching Frequency apply the signa l at the FSYNC test point. The external For 400kHz switching frequen cy, the following compo- clock frequency at FSYNC can be higher or lower than the nents need to be changed to: internal clock by 20%. Ensure that the duty cycle of the R4 = 73.2k external clock used has a minimum 100ns pulse width. L1 = 6.8H (recommend Coilcr aft XAL5050-682MEB) Spread-Spectrum Option (SPS) R1 = 16.5k The EV kit provides jumper JU3 that allows SPS to be pulled high (VL) or pulled low (PGND). Connect SPS C10 = 4,700pF high to enable spread spectrum where the operating C11 = 6.8pF frequency is varied 3% centered on FOSC. Connect Additional capacitance on C7 and C8 may be needed, SPS low to disable the spread-spectrum feature. depending on transient performance. Setting the Switching Frequency (FOSC) The EV kit switching frequency is set by a resistor, R FOSC (R4), connected from FOSC to AGND. Refer to TOC 08 in the Typical Operating Characteristics section in the MAX20002/MAX20003 IC data sheet for the correct R (R4) value. FOSC Maxim Integrated 2 www.maximintegrated.com