SP1938 DC-DC Step-Up Converter for White LED DESCRIPTION The SP1938 is a step-up DC/DC converter for white LED driver with over voltage protection. The device can driver one to four LEDs in series from a single cell Lithium Ion battery. Internal functions include current limiting; thermal shutdown; OVP and soft-start to prevent damage operate status. The SP1938 operates at 0.8MHz and from low input voltages as low as 1.5V; apply to Lithium-Ion powered systems. A low 95mV reference voltage minimizes power loss in the current setting resistor for better efficiency. The SP1938 is available in small package SOT-23-6L. APPLICATIONS z Battery Power Equipment z Notebook Computers z PDA z Cellular Phone FEATURES z Current Source with Over Voltage Protection z Fast 0.8MHz Switching Frequency z High Efficiency up to 87% z Drives up to Four LEDs From 3.2V Supply z Drives up to Six LEDs From a 5V Supply z Low Quiescent Current z Disconnects LEDs in Shutdown Mode z Internal Over Temperature and Current Limiting Shutdown Function z Internal Soft-Start Circuit z 36V Rugged Bipolar Switch Available in a Small SOT-23-6L Package PIN CONFIGURATION(SOT-23-6L) 2009/03/30 Ver.1 PART MARKING Page 1 SP1938 DC-DC Step-Up Converter for White LED TYPICAL APPLCATION CIRCUIT PIN DESCRIPTION Pin Symbol Description 1 SW 2 GND 3 FB 4 SHDN 5 OVP Over voltage Protection and Connect to the output capacitor of the Converter 6 VIN Supply Voltage Input Connect inductor/diode here Ground Pin Connect cathode of lowest LED and resistor here Combined active low enable and PWM control pin for LED dimming ORDERING INFORMATION Part Number Package SP1938S26RGB SOT-23-6L ※ Week Code : A ~ Z( 1 ~ 26 ) ; a ~ z( 27 ~ 52 ) ※ SP1938S26RGB : Tape Reel ; Pb – Free ; Halogen -Free 2009/03/30 Ver.1 Part Marking 98YW Page 2 SP1938 DC-DC Step-Up Converter for White LED BLOCK DIAGRAM ABSOULTE MAXIMUM RATINGS (TA=25℃ Unless otherwise specified) Parameter DC Supply Voltage SW Voltage FB Voltage SHDN Voltage Operating Temperature Maximum Junction Temperature Storage Temperature Symbol VIN VSW Value 18 36 Unit V V VFB 7 7 -40～85 125 -65～150 V V ℃ ℃ ℃ VSHDN TOPR TJ(Max) TS The IC has a protection circuit against static electricity. Do not apply high static electricity or high voltage that exceeds the performance of the protection circuit to the IC. 2009/03/30 Ver.1 Page 3 SP1938 DC-DC Step-Up Converter for White LED ELECTRICAL CHARACTERISTICS (TA=25℃, VIN=3V, VSHDN=3V, Unless otherwise specified) Parameter Operating Voltage Feedback Voltage FB Pin Bias Current Supply Current Conditions ISW=100mA, Duty Cycle = 66% Min. 2.5 86 VSHDN = 0V Switching Frequency Maximum Duty Cycle Switch Current Limit Switch Leakage Current Switch Saturation Voltage SHDN Voltage High SHDN Voltage Low SHDN Pin Current Over Voltage Protection 0.8 Vsw= 5V Isw = 200mA Typ. 2.8 0.1 1.2 85 320 0.01 150 Max. 18 110 150 3.5 1.0 1.6 5 1.5 0.4 VOUT rising 90 21 Unit V % nA mA μA MHz % mA μA mV V V uA V APPLICATION CIRCUIT 2009/03/30 Ver.1 Page 4 SP1938 DC-DC Step-Up Converter for White LED SOT-23-6L PACKAGE OUTLINE 2009/03/30 Ver.1 Page 5 SP1938 DC-DC Step-Up Converter for White LED Information provided is alleged to be exact and consistent. SYNC Power Corporation presumes no responsibility for the penalties of use of such information or for any violation of patents or other rights of third parties which may result from its use. No license is granted by allegation or otherwise under any patent or patent rights of SYNC Power Corporation. Conditions mentioned in this publication are subject to change without notice. This publication surpasses and replaces all information previously supplied. SYNC Power Corporation products are not authorized for use as critical components in life support devices or systems without express written approval of SYNC Power Corporation. ©The SYNC Power logo is a registered trademark of SYNC Power Corporation ©2004 SYNC Power Corporation – Printed in Taiwan – All Rights Reserved SYNC Power Corporation 7F-2, No.3-1, Park Street NanKang District (NKSP), Taipei, Taiwan 115 Phone: 886-2-2655-8178 Fax: 886-2-2655-8468 http://www.syncpower.com 2009/03/30 Ver.1 Page 6