Evaluates: MAX MAX17244 Evaluation Kit. General Description. Quick Start. Features. Table 1. EN Configuration (JU1)

Transcription

1 General Description The MAX744 evaluation kit (EV kit) demonstrates the MAX744 high-voltage, current-mode step-down converter with low operating current. The EV kit operates over a wide 6V to 36V input range and the output is set for 5V at.5a. The EV Kit switching frequency is set at.66mhz The EV kit comes with the MAX744ETESA+ installed. Features Wide 6V to 36V Input Supply Range Forced-PWM or Skip-Mode Operation Configurable Switching Frequency Current-Mode Controller with Force-PWM and Skip Modes 86% Peak Efficiency at V Input in Skip-Mode 89% Peak Efficiency at V Input in Forced-PWM FSYNC Input and Power-Good Output Proven 4-Layer oz Copper PCB Layout Demonstrates 065mil x 795mil Solution Size Fully Assembled and Tested Table. EN Configuration (JU) SHUNT POSITION -* -3 *Default position. Table. Mode of Operation (JU) *Default position. DESCRIPTION Connects the EN pin to the voltage at SUP for normal operation. Connects the EN pin to ground to enter shutdown mode. SHUNT POSITION MODE P MODE -* Connected to Forced-PWM mode -3 Connected to Skip mode Not installed Connected to an external clock Forced-PWM mode (device syncs to an external clock) Quick Start Required Equipment MAX744 EV kit 4V, A DC power supply Electronic load capable of.5a Digital voltmeter (DVM) Procedure The EV kit is fully assembled and tested. Follow the steps below to verify board operation. Caution: Do not turn on supplies until all connections are completed. ) Verify that jumpers JU and JU are in their default positions, as shown in Table and Table. ) Connect the power supply between the EXT_VBAT and nearest banana jacks. 3) Connect the.5a electronic load between the and nearest banana jacks. 4) Connect the DVM between the and nearest banana jacks. 5) Turn on the power supply. 6) Enable the electronic load. 7) Verify that the voltage at the test point is approximately 5V. Note: When a high input voltage or high load current is applied continuously, an external cooling fan may be required to prevent MAX744 from shutting down due to overtemperature. Ordering Information appears at end of data sheet ; Rev ; 3/7

2 Detailed Description of Hardware The EV kit demonstrates the MAX744 high-voltage, high-frequency, step-down converter with low operating current. The EV kit operates over a wide 6V to 36V input range and the output is set for 5V at.5a. Enable (EN) Place a shunt in the - position on jumper JU for normal operation. To place the device into shutdown mode, move the shunt on JU to the -3 position. Synchronization Input (FSYNC) The EV kit features jumper JU to control the synchronization input (FSYNC). Connect FSYNC to to enable skipmode operation. Connect to or to an external clock to enable fixed-frequency forced-pwm mode operation. The device can be synchronized to an external signal applied to FSYNC. To use an external clock, uninstall the shunt on JU and apply the signal at the FSYNC test point. The external clock frequency at FSYNC can be higher or lower than the internal clock by 0%. Ensure that the duty cycle of the external clock used has a minimum 00ns pulse width. Synchronizing Output (SYNC) The EV kit provides a test point EXT_5V to pull up the open-drain SYNC to an external 5V supply. SYNC is a 80 out-of-phase clock output relative to the internal oscillator at SYNC to create cascaded power supplies with multiple MAX744s. Setting the Switching Frequency (FOSC) The EV kit switching frequency is set to.66mhz by the resistor, R FOSC (R), connected from F OSC to. Refer to the Internal Oscillation section in the MAX744 IC data sheet for the equation and/or a graphical approach to selecting the correct R FOSC (R) value. Power-Good Output (PGOOD) The EV kit provides a PGOOD test point to monitor the status of the device output. PGOOD asserts when V rises above 95% of its regulation voltage. PGOOD deasserts when V drops below 9% of its regulation voltage. Output Connect FB to for a fixed +5V (EV kit default output) output voltage. To set the output to other voltages between V and 0V, remove R and connect a resistive-divider from output () to FB to. Use the following formula to determine the R4 and R6 of the resistive-divider network: where V FB = V. V R4 R6 = VFB Component Suppliers SUPPLIER WEBSITE Murata Americas Panasonic Corp. Würth Electronik GmbH & Co. KG Samsung Electromechanics Taiyo Yuden NXP Semiconductors Note: Indicate that you are using the MAX744 when contacting these component suppliers. Maxim Integrated

3 MAX744 EV Kit Bill of Materials Item Component Description Qty Reference Designators Manufacturer Part Number 000 Testpoints, Black 5 (x), (3x) Keystone Testpoints, Red 7, EXT_SUP, EXT_5V, FSYNC,, /PGOOD\, SYNC Keystone uF 0%, aluminum electrolytic capacitor (8x0.mm) C Panasonic EEE-TGH470UP uF 0%, X7R ceramic capacitor (06) C, C4 Taiyo Yuden UMK36AB7475KL uF 0%, X7R ceramic capacitor (0603) C3, C5 Murata GCM88R7H04KA57D uF 0%, 6V X7R ceramic capacitor (040) C6 Murata GRM55R7C04K 0007 uf 0%, 0V X7R ceramic capacitors (06) C7, C8 Samsung Electro CL3B6KPHNNNE 0008.uF 0%, 0V X7R ceramic capactor (0603) C0 Murata GRM88R7A5K pF 0% X7R ceramic capacitor (040) C Murata GRM55R7H0K 000 0pF 5% C0G ceramic capacitor (040) C3 Murata GRM555CH00J 00 3A, 60V Schottky diode (SOD8) D NXP PMEG6030ETP 00 JACKs, BANNANA, UNSULATED, PANEL MOUNT 4 EXT_VBAT,, (x) JOHNSON pin headers,.54mm, Comes in Pin Strips (CUT TO FIT) JU, JU SULLS PEC36SAAN 004.uH, 3A inductor (7mm x 6.9mm) L Wurth Electronics k ohms % resistor (040) R Any Any k ohms % resistor (040) R Any Any 007 0k ohms 5% resistor (040) R3 Any Any 008 k ohms 5% resistor (040) R5 Any Any ohms 5% resistor (0) R8 Any Any ohms 5% resistor (040) 3 R9, R0, R Any Any 00 00k ohms 5% resistor (040) R Any Any 00 Shunts SU, SU Kycon SX00-B 003 Step-down Converter (6 TQFN-EP 5x5x0.8mm) U Maxim MAX744ETESA+ 004 PC board: MAX744 EV KIT oz. Cu CMR MAX744 EV KIT 005 Not installed, ceramic capacitor (040) 0 C4, C5 006 Not installed, resistor (040) 0 R4, R6, R7 007 Not installed, resistor (0603) 0 R3 008 Maxim pads 0 EXT_VBAT,, (x) Maxim Integrated 3

4 MAX744 EV Kit PCB Layout Diagrams MAX744 EV Kit Top Silkscreen MAX744 EV Kit Top MAX744 EV Kit Layer MAX744 EV Kit Layer 3 Maxim Integrated 4

5 MAX744 EV Kit PCB Layout Diagrams (continued) MAX744 EV Kit Bottom MAX744 EV Kit Bottom Silkscreen Maxim Integrated 5

6 MAX744 EV Kit Schematic JU FSYNC PCC03SAAN R 00K R 6.5K % R0 0 R 0 C5 R4 R6 C3 0PF R % 0K C 000PF SYNC EXT_5V R5 K U MAX744ETESA+ FSYNC 4 FOSC 3 7 BST 8 R3 SHORT C0.UF R3 0K R7 R9 0 PGOOD C4 JU PCC03SAAN C6 0.UF L.UH D C3 0.UF C5 0.UF C 4.7UF C4 4.7UF C7 UF R8 0 C8 UF C 47UF 5V AT.5A EXT_VBAT EXT_SUP C A 6 SYNC PGOOD FB SUPSW 5 COMP SUP 0 6 EN 9 EP + Maxim Integrated 6

7 MAX744 EV Kit Minimal Component Schematic C3 0PF R 0K % C 000PF R 6.5K % C0.UF U MAX744ETESA+ 3 C6 0.UF L.UH D C3 0.UF C5 0.UF C7 UF C 4.7UF C4 4.7UF C8 UF 5V AT.5A EXT_VBAT C 47UF 7 C A 6 SYNC PGOOD 5 FSYNC 4 FOSC 3 4 FB SUPSW 5 COMP SUP 0 6 EN 9 7 BST 8 EP + Maxim Integrated 7

8 Ordering Information PART MAX744EVKIT# #Denotes RoHS compliant. TYPE EV Kit Maxim Integrated 8

9 Revision History REVISION NUMBER REVISION DATE DESCRIPTION PAGES CHANGED 0 3/6 Initial release 3/7 Updated General Description and Setting the Switching Frequency (FOSC) sections For pricing, delivery, and ordering information, please contact Maxim Direct at , or visit Maxim Integrated s website at. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. 07 Maxim Integrated Products, Inc. 9