SP1937 SYNC-POWER | Alldatasheet
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Technical content
2007/07/10 Ver.3 Page 1 SP1937 DC-DC Step-Up Converter for White LED DESCRIPTION APPLICATIONS The SP1937 is a step-up DC/DC converter for white LED driver with constant current. The device can driver one to four LEDs in series from a single cell Lithium Ion battery. Internal functions include current limiting; thermal shutdown and soft-s tart to prevent damage operate status. The SP1937 DC/DC converter operates at 1.2MHz and low output capacitor as small as 0.22uF; apply to Lithium-Ion powered systems. A low 95mV (Typ) reference voltage minimizes power loss in the current setting resistor for better efficiency. z Battery Power Equipment z Notebook Computers z PDA z Cellular Phone z Digital Cameras z MP3 Players z GPS Receivers FEATURES PIN CONFIGURATION SOT-23-5L SOT-353 ( SC-70-5L ) PART MARKING SOT-23-5L SOT-353 ( SC-70-5L ) Fast 1.2MHz Switching Frequency High Efficiency up to 85% Drives up to Four LEDs From 3.2V Supply Low Quiescent Current Disconnects LEDs in Shutdown Mode Internal Over Temperature and Current Limiting Shutdown Function 36V Rugged Bipolar Switch Small Package SOT-23-5L & SOT-353
2007/07/10 Ver.3 Page 2 SP1937 DC-DC Step-Up Converter for White LED TYPICAL APPLCATION CIRCUIT PIN DESCRIPTION SP1937S25RG Pin Symbol Description 1 SW Switch Pin.
2 GND Ground Pin
3 FB Feedback Pin. 4 SHDN Shutdown Pin. Active-low enable
5 VIN Supply V oltage Input
1 SW Switch Pin. 3 FB Feedback Pin. 4 SHDN Shutdown Pin. Active-low enable
5 GND Ground Pin
6 VIN Supply V oltage Input
ORDERING INFORMATION
Part Number Package Part Marking SP1937S25RG SOT-23-5L 97YW SP1937S35RG SOT-353 ( SC-70-5L ) 97YW ※ Week Code : A ~ Z( 1 ~ 26 ) ; a ~ z( 27 ~ 52 ) ※ SP1937S25RG : Tape Reel ; Pb – Free ※ SP1937S35RG : Tape Reel ; Pb – Free
2007/07/10 Ver.3 Page 3 SP1937 DC-DC Step-Up Converter for White LED BLOCK DIAGRAM ABSOULTE MAXIMUM RATINGS A=25 Unless otherwise specified)℃ Parameter Symbol Value Unit DC Supply V oltage V IN 20 V SW V oltage V SW 36 V FB V oltage V FB 10 V SHDN V oltage V SHDN 10 V Operating Temperature TOPR -40～85 ℃ Maximum Junction Temperature T J(Max) 125 ℃ Storage Temperature TS -65～150 ℃ 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.
2007/07/10 Ver.3 Page 4 SP1937 DC-DC Step-Up Converter for White LED
ELECTRICAL CHARACTERISTICS
(TA=25 , V℃ IN=3V , VSHDN=3V , Unless otherwise specified) Parameter Conditions Min. Typ. Max. Unit Operating V oltage 2.5 20.0 V Feedback V oltage I SW=100mA, Duty Cycle = 66% 86 110 mV FB Pin Bias Current 150 nA 2.8 3.5 mA Supply Current VSHDN = 0V 0.1 1.0 μA Switching Frequency 0.8 1.2 1.6 MHz Maximum Duty Cycle 85 % Switch Current Limit 320 mA Switch Leakage Current V SW= 5V 0.01 5 μA Switch Vcesat I SW = 200mA 150 mV SHDN V oltage High 1.5 V SHDN V oltage Low 0.4 V SHDN Pin Bias Current 90 uA
2007/07/10 Ver.3 Page 5 SP1937 DC-DC Step-Up Converter for White LED
APPLICATION INFORMATION
CH1: VCC / CH2: Vsw / CH3: Inductor current / R1= 6.8Ω
2007/07/10 Ver.3 Page 6 SP1937 DC-DC Step-Up Converter for White LED APPLICATION CIRCUIT ( For Portable System --- Series )
2007/07/10 Ver.3 Page 7 SP1937 DC-DC Step-Up Converter for White LED APPLICATION CIRCUIT ( For LCD Panel --- Series & Parallel )
2007/07/10 Ver.3 Page 8 SP1937 DC-DC Step-Up Converter for White LED SOT-23-5L PACKAGE OUTLINE
2007/07/10 Ver.3 Page 9 SP1937 DC-DC Step-Up Converter for White LED SOT-353 PACKAGE OUTLINE
2007/07/10 Ver.3 Page 10 SP1937 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 pate nt or patent rights of SYNC Power Corporation. Conditions mentioned in this publication ar e subject to change without notice. This p ublication 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 9F-5, No.3-2, Park Street NanKang District (NKSP), Taipei, Taiwan 115 Phone: 886-2-2655-8178 Fax: 886-2-2655-8468 http://www.syncpower.com