Evaluates: MAX17550 (MAX) in MAX17550 5V Output 5V Output Voltage Applications Evaluation Kit (MAX) General Description Quick Start The MAX17550 5V evaluation kit (EV kit) (MAX) is a fully Recommended Equipment assembled and tested circuit board that demonstrates the MAX17550 5V EV kit (MAX) performance of the MAX17550 60V, 25mA ultra-small, 60V adjustable, 0.5A DC power supply high-efficiency, synchronous step-down DC-DC converter in a 10-pin MAX package. The EV kit operates over a Electronic load up to 25mA wide input voltage range of 6V to 60V and provides up to Voltmeter 25mA load current at 5V output. It draws only 26A supply Procedure current under no-load conditions (EN/UVLO connected to V ). The EV kit is programmed to switch at a frequency The EV kit is fully assembled and tested. Follow the steps IN of 220kHz. The device is simple to use and easily configurable below to verify board operation. Caution: Do not turn on with minimal external components. It features cycle-by- the power supply until all connections are completed. cycle peak current-limit protection, undervoltage lockout, 1) Verify that shunts are installed on jumpers JU1, JU2 and thermal shutdown. (EN/UVLO). The EV kit comes installed with the MAX17550AUB+ in 2) Verify that jumper JU3 (MODE-PFM operation) is open. a 10-pin (3mm x 3mm) lead(Pb)-free/RoHS-compliant 3) Set the electronic load to constant-current mode, MAX package. 25mA, and disable the electronic load. 4) Connect the electronic loads positive terminal to the Features VOUT PCB pad. Connect the negative terminal to 6V to 60V Input Voltage Range the GND PCB pad. 5V Output, 25mA Continuous Current 5) Connect the voltmeter across the VOUT and GND 26A No-Load Supply Current PCB pads. EN/UVLO for On/Off Control and Programmable 6) Set the power-supply output to 24V. Disable the Input Undervoltage Lockout power supply. 7) Connect the power-supply output to the VIN PCB Programmable Switching Frequency pad. Connect the supply ground to the GND PCB Internal or Programmable Soft-Start pad. PFM or Forced-PWM Mode of Operation 8) Turn on the power supply. Open-Drain RESET Output 9) Enable the electronic load and verify that output voltage Peak Current-Limit Protection is 5V with respect to GND. Thermal Shutdown 10) Vary the input voltage from 6V to 60V. Proven PCB Layout 11) Vary the load current from 1mA to 25mA and verify that output voltage is 5V with respect to GND. Fully Assembled and Tested Note: While performing an output short-circuit test, it is possible for the ceramic output capacitor to oscillate with the wiring inductance between the capacitor and short- circuited load, and thereby cause the absolute maximum rating of the V pin (-0.3V) to be exceeded. The OUT resistor (R7) and the capacitor (C5) are included on this Ordering Information appears at end of data sheet. evaluation kit to protect against unintentional violation of the above mentioned rating. In the actual system design, parasitic board or wiring inductance should be minimized and the output-voltage waveform under short-circuit operation should be verified to ensure that the absolute MAX is a registered trademark of Maxim Integrated Products, Inc. maximum rating of the V pin is not exceeded. OUT 19-7595 Rev 0 4/15Evaluates: MAX17550 (MAX) in MAX17550 5V Output Evaluation Kit (MAX) 5V Output Voltage Applications RESET Output Detailed Description The EV kit provides a PCB pad to monitor the status of The MAX17550 5V EV kit (MAX) is a fully assembled and the RESET output. RESET goes high when the output volt- tested circuit board that demonstrates the performance age rises above 95% (typ) of its nominal regulated output of the MAX17550 60V, 25mA ultra-small, high-efficiency, voltage. RESET goes low when output voltage falls below synchronous step-down DC-DC converter in a 10-pin 92% (typ) of its nominal regulated voltage. MAX package. The EV kit operates over a wide input voltage range of 6V to 60V and provides up to 25mA load PFM or Forced-PWM Mode (MODE) current at 5V output. It draws only 26A supply current under The EV kit includes a jumper (JU3) to select the mode no-load conditions (EN/UVLO connected to VIN). The EV of operation of the converter. Install a shunt across JU3 kit is programmed to switch at a frequency of 220kHz. before powering up the EV kit to enable the forced-PWM The device is simple to use and easily configurable with operation. Keep JU3 open to enable the light-load PFM minimal external components. It features cycle-by-cycle operation. See Table 2 for proper JU3 settings. peak current-limit protection, undervoltage lockout, and thermal shutdown. Soft-Start The EV kit includes an EN/UVLO PCB pad and jumpers The EV kit offers a fixed 5ms soft-start time. Connect JU1 and JU2 to enable control of the converter output. capacitor C4 to adjust the soft-start time (t ). The minimum SS The MODE PCB pad and jumper JU3 are provided soft-start time is related to the output capacitance (C ) OUT for selecting the mode of operation of the converter. A and the output voltage (V ) by the following equation. OUT RESET PCB pad is available for monitoring the RESET t > 0.05 x C x V SS OUT OUT output. The RT/SYNC PCB pad can be used to synchronize where t is in milliseconds and C is in F. the EV kit switching frequency to an external clock fre- SS OUT quency. Use the following equation to determine the soft-start capacitance value (C ): SS Enable Control (JU1, JU2) C = 6.25 x t SS SS The EN/UVLO pin on the EV kit serves as an on/off where t is in milliseconds and C is in nanofarads. control while also allowing the user to program the input SS SS undervoltage-lockout (UVLO) threshold. Jumpers JU1 and External Synchronization (RT/SYNC) JU2 configure the EV kits output for turn-on/turn-off control. The EV kit provides a PCB pad to synchronize the EV See Table 1 for proper JU1, JU2 jumper configurations. kit switching frequency to an external clock frequency. Additionally, resistors R1 and R2 are included to set the Apply the external clock to the RT/SYNC PCB pad UVLO to a desired turn-on voltage. Refer to the Setting though an AC-coupling capacitor. Refer to the External the Input Undervoltage-Lockout Level section in the Synchronization section in the MAX17550 IC data sheet MAX17550 IC data sheet for additional information on for additional information on configuring the external setting the UVLO threshold voltage. clock and selecting the AC-coupling capacitor. Table 1. Enable Control (EN/UVLO) (JU1, JU2) SHUNT POSITION EN/UVLO PIN VOUT OUTPUT JU1 JU2 1-2 Open Connected to VIN Enabled Open 1-2 Connected to GND Disabled 1-2* 1-2 Connected to midpoint of R1, R2 resistor-divider Enabled at VIN 6V *Default position. Table 2. MODE Control (JU3) SHUNT POSITION MODE PIN MODE OF OPERATION 1-2 Connected to GND Forced PWM Open* Unconnected PFM *Default position. Maxim Integrated 2 www.maximintegrated.com