MAX16935EVKIT# Analog Devices

Evaluates: MAX16935 MAX16935 Evaluation Kit 2) Connect the power supply between the EXT VBAT General Description and nearest PGND test points. The MAX16935 evaluation kit (EV kit) demonstrates 3) Connect the 3.5A electronic load between the OUT the MAX16935 high-voltage, current-mode step-down converter with low operating current. The EV kit operates and nearest PGND test points. over a wide 3.5V to 36V input range and the output is set 4) Conn ect the DVM betwee n the OUT and nearest for 5V at 3.5A. PGND test poin ts. The EV kit comes with the MAX16935RAUE/V+ installed. 5) Turn on the power supply. 6) Enable the electronic load. Features and Benefits 7) Verify that the voltage at the OUT test point is approxi- Wide 3.5V to 36V Input Supply Range mately 5V. Forced-PWM or Skip-Mode Operation Programmable Switching Frequency Table 1. EN Configuration (JU1) Power-Good Output SHUNT DESCRIPTION Proven PCB Layout POSITION Fully Assembled and Tested Connects the EN pin to the voltage at SUP 1-2* for normal operation. Connects the EN pin to ground to enter Quick Start 2-3 shutdown mode. Required Equipment *Default position. MAX16935 EV kit 14V, 3A DC power supply Table 2. Mode of Operation (JU2) Electronic load capable of 3.5A SHUNT MODE PIN MODE Digital voltmeter (DVM) POSITION Forced-PWM mode Procedure 1-2* Connected to BIAS (device syncs to the The EV kit is fully assembled and tested. Follow the steps internal clock) below to verify board operation. Caution: Do not turn on supplies until all connections are made. Connected to 2-3 Skip mode AGND 1) Verify that jumpers JU1 and JU2 are in their default positions, as shown in Tables 1 and 2. Forced-PWM mode Connected to an Not installed (device syncs to an external clock external clock) *Default position. Ordering Information appears at end of data sheet. 19-6911 Rev 0 1/14Evaluates: MAX16935 MAX16935 Evaluation Kit of-phase clock output relative to the internal oscillator Detailed Description of Hardware at SYNCOUT to create cascaded power supplies with The EV kit demonstrates the MAX16935 high-voltage, multiple MAX16935s. high-frequency, step-down converter with low operating current. The EV kit operates over a wide 3.5V to 36V input Setting the Switching Frequency (FOSC) range and the output is set for 5V at 3.5A. The EV kit switching frequency is set by a resistor, R FOSC (R2), connected from FOSC to AGND. Refer to Figure 3. Enable (EN) in the MAX16935 IC data sheet for a graphical approach Place a shunt in the 1-2 position on jumper JU1 for normal of selecting the correct R (R2) value. FOSC operation. To place the device into shutdown mode, move the shunt on JU1 to the 2-3 position. Power-Good Output (PGOOD) The EV kit provides a PGOOD test point to monitor the Synchronization Input (FSYNC) status of the device output. PGOOD asserts when VOUT The EV kit features jumper JU2 to control the synchro- rises above 95% of its regulation voltage. PGOOD nization input (FSYNC). The device synchronizes to an deasserts when VOUT drops below 92% of its regulation external signal applied to FSYNC. Connect FSYNC to voltage. AGND to enabl e skip-mode operation. Connect to BIAS or to an external clock to enable fixed-frequency forced- Output PWM mode operation. Connect FB to BIAS for a fixed +5V (EV kit default To use an external clock, uninstall the shunt on JU2 and output) or a fixed +3.3V output voltage. To set the output apply the signal at the FSYNC test point. The external to other voltages between 1V and 10V, connect a resis- clock frequency at FSYNC can be higher or lower than the tive divider from output (OUT) to FB to AGND. Use the internal clock by 20%. Ensure that the duty cycle of the following formula to determine the R4 and R6 of the resis- external clock used has a minimum 100ns pulse width. tive divider network: Synchronizing Output (SYNCOUT) V OUT R 4=R6 1 The EV kit provides jumper JU3 to pull up the open-drain V FB SYNCOUT to the OUT voltage. SYNCOUT is a 180 out- where V = 1V. FB Maxim Integrated 2 www.maximintegrated.com