BCR401W LED Driver Features • LED drive current of 10mA • Output current adjustable up to 60mA with 3 4 external resistor 2 1 • Supply voltage up to 18V • Easy paralleling of drivers to increase current • Low voltage overhead of 1.2V • High current accuracy at supply voltage variation • No EMI • Reduced output current at higher temperatures - negative thermal coefficient of -0.3% / K • RoHS compliant (pb-free) small SOT343 package • Qualified according AEC Q101 Applications • Channel letters for advertising, LED strips for decorative lighting • Aircraft, train, ship illumination • Retrofits for general lighting, white goods like refrigerator lighting • Medical lighting General Description The BCR401W is a cost efficient LED driver to drive low power LED’s. The advantages towards resistor biasing are: • homogenous light output despite varying forward voltages in different LED strings • homogenous light output of LED’s despite voltage drop across long supply lines • homogenous light output independent from supply voltage variations • longer lifetime of the LED’s due to reduced output current at higher temperatures (negative thermal coefficient) The advantages towards discrete solutions are: • lower assembly cost • smaller form factor • better quality due to less soldering points • higher output current accuracy due to pretested LED drivers Dimming is possible by using an external digital transistor at the ground pin. The BCR401W can be operated at higher supply voltages by putting LED’s between the power supply +VS and the power supply pin of the LED driver. You can find further details in the application note AN182. The BCR401W is a perfect fit for numerous low power LED applications by combining small form factor with low cost. These LED drivers offer several advantages to resistors like significantly higher current control at very low voltage drop ensuring high lifetime of LED’s. 1 2010-01-12 BCR401W Pin Configuration Typical Application +Vs 4 B C R 401W 3 3 R e x t V d ro p 4 1 2 1 EHA07188 Type BCR401W Marking W5s 1 = GND 2 Is Io u t Pin Configuration 2 = Iout 3 = VS Package 4 = R ext SOT343 Maximum Ratings Parameter Symbol Supply voltage VS 18 V Output current Iout 60 mA Output voltage Vout 16 V Reverse voltage between all terminals VR 0.5 Total power dissipation, TS ≤ 95 °C Ptot 500 mW Junction temperature Tj 150 °C Storage temperature Tstg Value Unit -65 ... 150 Thermal Resistance Parameter Symbol Junction - soldering point1) RthJS Value Unit 110 K/W 1For calculation of R thJA please refer to Application Note Thermal Resistance 2 2010-01-12 BCR401W Electrical Characteristics at TA=25°C, unless otherwise specified Symbol Parameter Values Unit min. typ. max. VBR(CEO) 18 - - IS 350 440 540 hFE - 150 - - Rint 66 79 94 Ω Iout 9 10 11 mA Vdrop - 0.79 - V VSmin - 1.2 - V ∆Iout/Iout - -0.3 - %/K ∆Iout/Iout - 2 - %/V Characteristics Collector-emitter breakdown voltage - IC = 100 µA, IB = 0 Supply current µA VS = 10 V DC current gain IC = 50 mA, VCE = 1 V Internal resistor IRint = 10 mA Output current VS = 10 V, Vout = 7.6 V Voltage drop (VS - VE) Iout = 20 mA DC Characteristics with stabilized LED load Lowest sufficient supply voltage overhead Iout > 8mA Output current change versus T A VS = 10 V Output current change versus VS VS = 10 V 3 2010-01-12 BCR401W Total power dissipation Ptot = f (TS) Permissible Pulse Load RthJS = f (tp) 10 3 550 mW 450 RthJS P tot 400 350 10 2 300 250 200 D = 0,5 0,2 0,1 0,05 0,02 0,01 0,005 0 10 1 150 100 50 0 0 15 30 45 60 90 105 120 °C 75 10 0 -6 10 150 TS 10 -5 10 -4 10 -3 10 -2 s 10 0 tp Permissible Pulse Load Ptotmax / PtotDC = f (tp) P totmax/P totDC 10 2 - D=0 0.005 0.01 0.02 0.05 0.1 0.2 0.5 10 1 10 0 -6 10 10 -5 10 -4 10 -3 10 -2 s 10 0 tp 4 2010-01-12 BCR401W Output current versus supply voltage Supply current versus supply voltage Iout = f (V S); R ext = Parameter IS = f(VS) Load: two LEDs with VF = 3.8V in series Load: two LEDs with VF = 3.8V in series 10 -1 10 -3 Rext = 36 Ohm Rext = 82 Ohm Rext = 160 Ohm Rext = open A IS Iout A 10 -2 10 -3 0 10 -4 2 4 6 8 10 12 14 16 V 10 -5 0 20 2 4 6 8 10 12 14 16 VS V 20 VS Output current versus external resistor Output current versus reference voltage Iout = f (Rext ); VS = 10V; V out = 7.6V Iout = f (V DROP); VS = 10V; V out = 7.6V 10 -1 0.06 A A 0.04 Iout Iout 10 -2 10 -3 0.03 0.02 10 -4 0.01 0 1 10 10 2 OHM 10 10 -5 0.6 3 Rext. 0.65 0.7 0.75 0.8 0.85 0.9 V 1 Vdrop 5 2010-01-12 BCR401W Standard Application Circuit: Application Circuit: supply voltages >18V +Vs Vsupply B C R 401W 3 IOUT + IDRIVER R ext Vdrop LEDs 4 Rsense (optional) BCR401W BCR402W Vs 1 Rext 2 Is Iout GND IDRIVER Iout IOUT LEDs Application hints BCR401W serves as an easy to use constant current source for LEDs. In stand alone application an external resistor can be connected to adjust the current from 10 mA to 60 mA. Rext can be determined by using the diagram 'Output current versus external resistor', or by refering to diagram 'Output current versus reference voltage'. Look for your desired output current on the y axis and read out the corresponding Vdrop. Calculate Rext: Rext = Vdrop / (Iout -(Vdrop/Rint)) Please take into account that the resulting output currents will be slightly lower due to the self heating of the component and the negative thermal coefficient. Please visit our web site for application notes: www.infineon.com/lowcostleddriver • AN077 gives hints to thermal design • AN182 provides a guideline for replacing resistor biasing with BCR401W / BCR402W constant current sources in 12 & 24V striplight applications 6 2010-01-12 Package SOT343 BCR401W Package Outline 0.9 ±0.1 2 ±0.2 0.1 MAX. 1.3 0.1 A 1 2 0.1 MIN. 0.15 1.25 ±0.1 3 2.1 ±0.1 4 0.3 +0.1 -0.05 +0.1 0.15 -0.05 0.6 +0.1 -0.05 4x 0.1 0.2 M M A Foot Print 1.6 0.8 0.6 1.15 0.9 Marking Layout (Example) Manufacturer 2005, June Date code (YM) BGA420 Type code Pin 1 Standard Packing Reel ø180 mm = 3.000 Pieces/Reel Reel ø330 mm = 10.000 Pieces/Reel 0.2 2.3 8 4 Pin 1 2.15 1.1 7 2010-01-12 BCR401W Edition 2009-11-16 Published by Infineon Technologies AG 81726 Munich, Germany 2009 Infineon Technologies AG All Rights Reserved. Legal Disclaimer The information given in this document shall in no event be regarded as a guarantee of conditions or characteristics. With respect to any examples or hints given herein, any typical values stated herein and/or any information regarding the application of the device, Infineon Technologies hereby disclaims any and all warranties and liabilities of any kind, including without limitation, warranties of non-infringement of intellectual property rights of any third party. Information For further information on technology, delivery terms and conditions and prices, please contact the nearest Infineon Technologies Office (<www.infineon.com>). Warnings Due to technical requirements, components may contain dangerous substances. For information on the types in question, please contact the nearest Infineon Technologies Office. Infineon Technologies components may be used in life-support devices or systems only with the express written approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system or to affect the safety or effectiveness of that device or system. Life support devices or systems are intended to be implanted in the human body or to support and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may be endangered. 8 2010-01-12