AL5802 30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER Description Pin Assignments ADVANCE INFORMATION NEW PRODUCT The AL5802 combines a high gain NPN transistor with a prebiased NPN transistor to make a simple small footprint LED driver. (Top View) The LED current is set by an external resistor connected to from REXT pin (6) to GND pin (4), the internal high gain transistor develops approximately 0.6V across the external resistor. 6 5 4 Q1 Q2 The AL5802 open-collector output can operate from 0.8V to 30V enabling it to operate from 5V to 24V power supplies without additional components. 1 PWM dimming of the LED current can be achieved by either driving the BIAS pin (2) with a low impedance voltage source, or driving the EN pin (3) with an external opencollector NPN transistor or open-drain N-channel MOSFET. 2 3 SOT26 The AL5802 is available in a SOT26 package and is ideal for driving 20mA to 120mA LED currents. Features Applications • Reference voltage VRSET = 0.65V • Linear LED driver • -40 to 125ºC temperature range • LED signs • 0.8V to 30V open-collector output • Offline LED luminaries • Negative temperature co-efficient – automatically reduce the LED current at high temperatures • Low thermal impedance SOT26 with copper leadframe • SOT26: Available in “Green” Molding Compound (No Br, Sb) • Qualified to AEC-Q101 Standards for High Reliability Typical Application Circuit AL5802 Document number: DS35516 Rev.4 - 2 1 of 11 www.diodes.com November 2011 © Diodes Incorporated AL5802 30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER Pin Descriptions ADVANCE INFORMATION NEW PRODUCT Pin Number 1 2 Name OUT BIAS 3 EN 4 GND 5 FB 6 REXT Function Open-collector LED driver output Biases the open collector output transistor Enable pin for PWM dimming. Provides access to the base of Q2 and collector of Q1 Ground reference point for setting LED current Feedback pin. Should be connected to pin 6. Current sense pin. LED current sensing resistor should be connected from here to GND. Functional Block Diagram Fig. 1 Block Diagram Absolute Maximum Ratings Symbol VOUT VBIAS VFB VEN VREXT IOUT TJ TST Characteristics Output voltage relative to GND BIAS voltage relative to GND (Note 1) LED voltage relative to GND EN voltage relative to GND REXT voltage relative to GND Output current Operating junction temperature Storage temperature Values 30 30 6 6 6 150 -40 to 150 -55 to 150 Unit V V V V V mA °C °C These are stress ratings only. Operation outside the absolute maximum ratings may cause device failure. Operation at the absolute maximum rating for extended periods may reduce device reliability. Notes: 1.With pins 5 and 6 connected together. AL5802 Document number: DS35516 Rev.4 - 2 2 of 11 www.diodes.com November 2011 © Diodes Incorporated AL5802 30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER ADVANCE INFORMATION NEW PRODUCT Package Thermal Data Characteristic Power Dissipation (Note 2) @ TA = 25°C Power Dissipation (Note 3) @ TA = 25°C Power Dissipation (Note 4) @ TA = 25°C Thermal Resistance, Junction to Ambient Air (Note 2) @ TA = 25°C Thermal Resistance, Junction to Ambient Air (Note 3) @ TA = 25°C Thermal Resistance, Junction to Ambient Air (Note 4) @ TA = 25°C Notes: Symbol PD RθJA Value 0.37 0.87 1 335 143 120 Unit W °C/W 2.Device mounted on FR-4 PCB, 2oz with minimum recommended pad layout. 3.Device mounted on 25mm x 25mm 2oz copper board. 4.Device mounted on 50mm x 50mm 2oz copper board. Recommended Operating Conditions Symbol VBIAS VOUT ILED TA Notes: Parameter Supply voltage range OUT voltage range LED pin current (Note 5) Operating ambient temperature range Min 4.5 0.8 10 -40 Max 30 30 120 125 Unit V mA °C 5.Subject to ambient temperature, power dissipation and PCB. Electrical Characteristics NPN Transistor – Q1 @TA = 25°C unless otherwise specified Symbol Characteristic V(BR)CEO Collector-Emitter Breakdown Voltage (Note 6) V(BR)EBO Emitter-Base Breakdown Voltage ICEX Collector Cutoff Current IBL Base Cutoff Current hFE VCE(SAT) VBE(SAT) DC Current Gain Collector-Emitter Saturation Voltage Base-Emitter Saturation Voltage Test Condition IC = 1.0mA, IB = 0 IE = 10µA, IC = 0 VCE = 30V, VEB(OFF) = 3.0V VCE = 30V, VEB(OFF) = 3.0V IC = 100µA, VCE = 1.0V IC = 1.0mA, VCE = 1.0V IC = 10mA, VCE = 1.0V IC = 10mA, IB = 1.0mA IC = 10mA, IB = 1.0mA Min 40 6.0 Typ Max 50 50 Unit V V nA nA ⎯ ⎯ 40 70 100 300 0.20 0.85 0.65 V V NPN Pre-biased Transistor – Q2 @TA = 25°C unless otherwise specified Symbol V(BR)CBO V(BR)CEO V(BR)EBO ICBO IEBO VCE(SAT) hFE R1 Characteristic Collector-Base Breakdown Voltage Collector-Emitter Breakdown Voltage (Note 6) Emitter-Base Breakdown Voltage Collector Cut-Off Current Emitter Cut-Off Current Collector-Emitter Saturation Voltage (Note 6) DC Current Gain (Note 6) Input Resistance Test Condition IC = 50μA, IE = 0 IC = 1mA, IB = 0 IE = 50µA, IC = 0 VCB = 30V, IE = 0 VEB = 4V, IC = 0 IC = 10mA, IB = 1mA VCE = 5V, IC = 150mA Min 30 30 5.0 100 7 Typ 10 Max 0.5 0.5 0.3 Unit V V V µA µA V 13 kΩ *Characteristics of transistor only. Notes: 6. Measured under pulsed condition. Pulse width = 300µs. Duty cycle ≤2%. AL5802 Document number: DS35516 Rev.4 - 2 3 of 11 www.diodes.com November 2011 © Diodes Incorporated AL5802 30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER ADVANCE INFORMATION NEW PRODUCT Thermal Characteristics AMBIENT TEMPERAURE (°C) Fig. 2Derating Curve Fig. 3Max Power vs. Area Fig. 4Thermal Resistance vs. Area AL5802 Document number: DS35516 Rev.4 - 2 4 of 11 www.diodes.com November 2011 © Diodes Incorporated AL5802 30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER ADVANCE INFORMATION NEW PRODUCT Typical Performance Characteristics Fig. 5 Output Current vs. Vout Fig. 8 Output Current vs. Vout Fig. 7 Output Current vs. Vout Fig. 9 Output Current vs. Vout Notes Fig. 6 Output Current vs. REXT Fig. 10 Output Current vs. Vbias 7.Vout in the “Output current Vs Vout“ graphs limited by power dissipation in the device AL5802 Document number: DS35516 Rev.4 - 2 5 of 11 www.diodes.com November 2011 © Diodes Incorporated AL5802 ADVANCE INFORMATION NEW PRODUCT 30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER Fig. 11 Output Current vs. Vbias Fig. 12 Output Current vs. Vbias Fig. 13 Output Current vs. Vbias AL5802 Document number: DS35516 Rev.4 - 2 6 of 11 www.diodes.com November 2011 © Diodes Incorporated AL5802 30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER Application Information ADVANCE INFORMATION NEW PRODUCT The AL5802 has been designed for driving low current LEDs with typical LED current of 20mA to 100mA. It provides a cost effective way for driving low current LEDs compared with more complex switching regulator solutions. Furthermore, it reduces the PCB board area of the solution as there is no need for external components like inductors, capacitors and switching diodes. Figure 14 shows a typical application circuit diagram for driving an LED or string of LEDs. The NPN transistor Q1 measures the LED current by sensing the voltage across an external resistor REXT. Q1 uses its VBE as reference to set the voltage across REXT and controls the base current into Q2. Q2 operates in linear mode to regulate the LED current. The LED current is ILED = VBE(Q1) / REXT From this, for any required LED current the necessary external resistor REXT can be calculated from REXT = VBE(Q1) / ILED Two or more AL5802 can be connected in parallel to construct higher current LED strings as shown in Figure 15. Fig. 14Typical Application Circuit for Linear Mode Current Sink LED Driver Consideration of the expected linear mode power dissipation must be factored into the design, with respect to the AL5802's thermal resistance. The maximum voltage across the device can be calculated by taking the maximum supply voltage less the voltage across the LED string. VCE(Q2) = VCC – VLED – VBE(Q1) 2 PD = VCE(Q2) * ILED + ( VCC – VBE(Q2) – VBE(Q1)) / R1 As the output current of AL5802 increases, it is necessary to provide appropriate thermal relief to the device. The power dissipation supported by the device is dependent upon the PCB board material, the copper area and the ambient temperature. The maximum dissipation the device can handle is given by: PD = ( TJ(MAX) - TA) /RθJA Refer to the thermal characteristic graphs on page 4 for selecting the appropriate PCB copper area. Fig. 15Application Circuit for Increasing LED Current AL5802 Document number: DS35516 Rev.4 - 2 7 of 11 www.diodes.com November 2011 © Diodes Incorporated AL5802 30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER ADVANCE INFORMATION NEW PRODUCT PWM dimming can be achieved by driving the EN pin. An external open-collector NPN transistor or open-drain N-channel MOSFET can be used to drive the EN pin as shown in Figure 16. Dimming is achieved by turning the LEDs ON and OFF for a portion of a single cycle. The PWM signal can be provided by a micro-controller or analog circuitry. Figure 17 is a typical response of LED current vs PWM duty cycle on the EN pin. -or- Fig. 16Application Circuits for LED Driver with PWM Dimming Functionality 60 LED CURRENT (mA) 50 40 30 20 10 0 0 20 40 60 80 PWM DUTY CYCLE (%) 100 Fig. 17 Typical LED current response vs.PWM duty cycle for REXT = 13Ω at 400Hz PWM frequency AL5802 Document number: DS35516 Rev.4 - 2 8 of 11 www.diodes.com November 2011 © Diodes Incorporated AL5802 30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER ADVANCE INFORMATION NEW PRODUCT SDM10U45LP VS To remove the potential of incorrect connection of the power supply damaging the lamp’s LEDs, many systems use some form of reverse polarity protection. One solution for reverse input polarity protection is to simply use a diode with a low VF in-line with the driver/LED combination. The low VF increases the available voltage to the LED stack and dissipates less power. A circuit example is presented in Fig. 18 using Diodes Inc. SBR® (Super Barrier Rectifier) technology. An SDM10U45LP (0.1A/45V) is shown, providing exceptionally low VF for its package size of 1mm x 0.6mm, equivalent to an 0402 chip style package. Other reverse voltage ratings are also available in Diodes’ website such as the SBR02U100LP (0.2A/100V) or SBR0220LP (0.2A/20V). AL5802 RS Fig. 18 Application circuit for LED driver with reverse polarity protection Automotive applications commonly use this method for reverse battery protection. A second approach, shown in Fig. 19, improves upon the method shown in Fig. 18. Whereas the method in Fig. 18 protects the light engine, it will not function until the problem has been diagnosed and corrected. BAS40BRW VS The method shown in Fig. 19 not only provides reverse polarity protection, it also corrects the reversed polarity, allowing the light engine to function. The BAS40BRW incorporates four low VF, Schottky diodes into a single package and allows more voltage available for the LED stack and dissipates less power that standard rectifier bridges. AL5802 RS Fig. 19 Application circuit for LED driver with assured operation regardless of polarity SBR is a registered trademark of Diodes Incorporated. 9 of 11 AL5802 Document number: DS35516 Rev.4 - 2 www.diodes.com November 2011 © Diodes Incorporated AL5802 30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER Ordering Information Packaging (Notes 8&9) SOT26 AL5802 Notes: Quantity 3,000/Tape & Reel 7” Tape and Reel Part Number Suffix -7 8.EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied, see EU Directive 2002/95/EC Annex Notes. 9.Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website athttp://www.diodes.com. Marking Information L102 Date Code Key Year 2011 Code Y Month Code Jan 1 2012 Z Feb 2 L102 = Product Type Marking Code YM = Date Code Marking Y = Year (ex: Y = 2011) M = Month (ex: 9 = September) YM ADVANCE INFORMATION NEW PRODUCT Device 2013 A Mar 3 Apr 4 2014 B May 5 Jun 6 2015 C Jul 7 Aug 8 2016 D Sep 9 Oct O 2017 E Nov N Dec D Package Outline Dimensions A B C H K J AL5802 Document number: DS35516 Rev.4 - 2 M D L 10 of 11 www.diodes.com SOT26 Dim Min Max Typ A 0.35 0.50 0.38 B 1.50 1.70 1.60 C 2.70 3.00 2.80 D ⎯ ⎯ 0.95 H 2.90 3.10 3.00 J 0.013 0.10 0.05 K 1.00 1.30 1.10 L 0.35 0.55 0.40 M 0.10 0.20 0.15 0° 8° α ⎯ All Dimensions in mm November 2011 © Diodes Incorporated AL5802 30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER Suggested Pad Layout ADVANCE INFORMATION NEW PRODUCT C2 Z C2 C1 G Y Dimensions Value (in mm) Z 3.20 G 1.60 X 0.55 Y 0.80 C1 2.40 C2 0.95 X IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated website, harmless against all damages. Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel. Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application. Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings noted herein may also be covered by one or more United States, international or foreign trademarks. LIFE SUPPORT Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein: A. Life support devices or systems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in significant injury to the user. B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systemsrelated information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems. Copyright © 2011, Diodes Incorporated www.diodes.com AL5802 Document number: DS35516 Rev.4 - 2 11 of 11 www.diodes.com November 2011 © Diodes Incorporated