SC120/SC121 EVB Evaluation Board User’s Guide POWER MANAGEMENT Description Feature Content SC120/SC121EVB is the evaluation board (EVB) for the SC120 and SC121ULTRT Low Voltage Synchronous Boost Converters. Both devices are available in the MLPD-UT 1.5×2 mm 6 lead package. The SC120 is also available in the SOT23-6 package. The EVB is designed to provide a working demonstration of the SC120 or SC121. • • • • Standard Schematic Standard Bill of Materials Layout Operation This guide contains information relating to the usage of the EVB and should be used in conjunction with the datasheet for the device. Component values on the EVB may vary per specific customer requirements. The datasheet contains detailed information including the electrical characteristics and the detailed features of the device. This guide can be used to familiarize the user with the features of the device and for testing electrical characteristics of particular interest to the reader. SC120/SC121 EVB With SC120UL/SC121UL Device (MLPD-UT-6 1.5×2mm package) Rev. 1.1 © 2011 Semtech Corporation 1 SC120/SC121 EVB SC120SK EVB With SC120SK Device (SOT23-6 package) Notice: All referenced brands, product names, service names and trademarks are the property of their respective owners. 2 SC120/SC121 EVB Schematic Drawings SC120/SC121 EVB R4 PTP2 0 JP1 J_LOOP 1 TP3 VIN 3 R3 TP7 GND 100kΩ SW1 TP4 EN TP2 GND 5 4 2 1 4 C1 2 C4 No Pop R5 TP6 VOUT L1 2 U1 J1 VIN TP1 LX J2 VOUT 4.7μH JP2 - ENL SC120UL/ SC121UL LX IN EN GND 10μF 10μF OUT T FB 1 No pop 6 5 PAD Down 6 3 Up C5 C3 C2 10μF 10μF 1 R6 0Ω R1 499kΩ R2 1MΩ 2 TP8 TP9 GND GND SW PUSHBUTTON DPDT SC120SK EVB R4 PTP2 0 JP1 J_LOOP 1 TP3 VIN R3 J1 VIN TP7 GND 1 TP4 EN TP2 GND 100kΩ SW1 5 4 2 1 Down 6 3 Up 6 C1 C4 10μF 10μF 2 TP6 VOUT L1 2 U1 TP1 LX No Pop R5 J2 VOUT 4.7μH SC120SK IN EN GND LX OUT FB JP2 - ENL 3 C5 No pop 4 5 C3 C2 10μF 10μF 1 R6 0Ω R1 499kΩ R2 1MΩ 2 TP8 TP9 GND GND SW PUSHBUTTON DPDT 3 SC120/SC121 EVB Standard Bill of Materials Reference Value Footprint Hardware Notes R1 499kΩ 0603 R2 1MΩ 0603 R3 100kΩ 0603 Pull-up resistor from EN to VIN R4 0 0603 Shorting bar is provided offset, with only one terminal connected. Install shorting bar to bypass inductor current sense loop. R5 No Pop 2512 Not populated, optional load resistor R6 0 0603 R6 is connected in series with R1. R6 permits using two resistors in series for a large (effective) value of R1 (see datasheet). SW1 DPDT TP1 Test point 0.040 LX pin voltage sense TP3 Test point 0.040 IN pin voltage sense TP4 Test point 0.040 EN pin voltage sense TP5 Test point 0.040 FB pin voltage sense TP6 Test point 0.040 OUT pin voltage sense TP2, TP7, TP8, TP9 Test point 0.040 Ground L1 4.7μH 7 x 4 (mm) SC120UL or SC121UL 1.5 x 2 (mm) SC120SK 2.8 x 2.9 (mm) C1, C2 22μF 0805 Capacitor, X5R dielectric, 6.3V rating, Murata GRM21BR60J226M C3, C4 No Pop 1206 Not populated C5 No Pop 0603 Feedback capacitor — optional JP1 Berg-2pin 2-100 Inductor current sense loop connections — external loop connector provided JP2 Berg-2pin 2-100 Short = 3.3V, open = resistor programmed PTP2 SLX J1 Banana Jack Input J2 Banana Jack Output Valid for 1.8V output. Push-button switch, down position enables output. Inductor, Murata LQH43MN4R7K03 Semtech integrated circuit — MLPD-UT-6 package U1 Semtech integrated circuit — SOT23-6 package PRB-TP-5031 Note: Component values on the EVB may vary per specific customer requirements. 4 SC120/SC121 EVB Layout Drawings — SC120/SC121 EVB Top layer metal and silkscreen 5 SC120/SC121 EVB Layout Drawings — SC120/SC121 EVB Bottom layer metal (top-side view) with top-side silkscreen shown for reference 6 SC120/SC121 EVB Layout Drawings — SC120SK EVB Top layer metal and silkscreen 7 SC120/SC121 EVB Layout Drawings — SC120SK EVB Bottom layer metal (top-side view) with top-side silkscreen shown for reference 8 SC120/SC121 EVB Operation The SC120/SC121 EVB provides configuration options for any SC120 or SC121 application. The following describes the standard configuration. If an EVB is requested with a non-standard configuration, some of the standard values or configurations will differ from this description. The output voltage can be set to 3.3V using internal programming by installing a jumper on JP1. Any other voltage from 1.8V to 5.0V can be programmed using resistors R1, R2, R6, and capacitor C5. R1 and R2 are the programming resistors described in the datasheet, there designated R1 and R2, respectively. The EVB is provided with R1 = 499kΩ and R2 = 1MΩ, for an output voltage of 1.8V. R6 is in series with R1, and is useful for obtaining high values for R1 as the sum of R1 and R6, or for dividing R1 into two resistors to mitigate environmental concerns if a large value of R1 is desired. The EVB is provided with R6 = 0Ω. C5 is also described in the datasheet, there designated C FB. It is used to improve the PSAVE ripple amplitude if needed, as described in the datasheet. The EVB is provided with C5 removed. The input supply is connected using banana jacks J1. The IN sense test point (TP3) is provided for input monitoring, or for Kelvin sense feedback to the input supply. The output load is connected using banana jacks J2. The OUT sense test point (TP6) provides a sense connection to the output capacitor. Two sets of capacitor pads are provided for both the input and output capacitors to permit devices of different package sizes, either 0805 or 1206. The enable pin is pulled up to IN with a 100kΩ resistor, R3. The pushbutton switch connects EN to ground to disable the SC120/SC121 when the button is in the up position. When the pushbutton is in the down position, the switch is open, EN is pulled high, and the SC120/SC121 is enabled. The inductor is connected from IN to LX by one of three methods. A jumper can be installed on JP1 to complete the inductor current path from the input supply. A wire loop can be connected across JP1 for use with a current probe to monitor inductor current. R4 is in parallel with JP1. A shorting bar is included soldered to only one R4 pad. Replace the shorting bar across both R4 pads to bypass the current sense loop. A Tektronix scope probe connection point (PTP2) is provided to monitor the LX pin voltage. Alternatively, LX pin voltage can be monitored using TP1. R5 is an unpopulated resistor pad that is provided for connection of a fixed load resistor directly on the board. 9 SC120/SC121 EVB © Semtech 2011 All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof does not convey nor imply any license under patent or other industrial or intellectual property rights. Semtech assumes no responsibility or liability whatsoever for any failure or unexpected operation resulting from misuse, neglect improper installation, repair or improper handling or unusual physical or electrical stress including, but not limited to, exposure to parameters beyond the specified maximum ratings or operation outside the specified range. SEMTECH PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHORIZED OR WARRANTED TO BE SUITABLE FOR USE IN LIFESUPPORT APPLICATIONS, DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF SEMTECH PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE UNDERTAKEN SOLELY AT THE CUSTOMER’S OWN RISK. Should a customer purchase or use Semtech products for any such unauthorized application, the customer shall indemnify and hold Semtech and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs damages and attorney fees which could arise. Notice: All referenced brands, product names, service names and trademarks are the property of their respective owners. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805) 498-2111 Fax: (805) 498-3804 www.semtech.com 10