TL4242 www.ti.com .............................................................................................................................................................. SLVS641A – APRIL 2008 – REVISED MAY 2009 ADJUSTABLE LED DRIVER FEATURES 1 • • • • • • • • DRJ (QFN) PACKAGE (TOP VIEW) Adjustable Constant Current up to 500 mA (±5%) Wide Input Voltage Range up to 42 V Low Drop Voltage Open-Load Detection Overtemperature Protection Short-Circuit Proof Reverse-Polarity Proof Wide Temperature Range: –40°C to 150°C PWM 1 8 GND 2 Exposed 7 Thermal 3 6 Pad REF 4 ST 5 I NC Q D NC – No internal connection DESCRIPTION/ORDERING INFORMATION The TL4242 is an integrated adjustable constant-current source, driving loads up to 500 mA. The output current level can be adjusted via an external resistor. The device is designed to supply high-power LEDs (for example, OSRAM Dragon LA W57B) under the severe conditions of automotive applications, resulting in constant brightness and extended LED lifetime. It is provided in the DRJ (QFN) package. Protection circuits prevent damage to the device in case of overload, short circuit, reverse polarity, and overheat. The connected LEDs are protected against reverse polarity as well as excess voltages up to 45 V. The integrated PWM input of the TL4242 permits LED brightness regulation by pulse-width modulation (PWM). Due to the high input impedance of the PWM input, the LED driver can be operated as a protected high-side switch. The TL4242 is characterized for operation from –40°C to 150°C. An external shunt resistor in the ground path of the connected LEDs is used to sense the LED current. A regulation loop holds the voltage drop at the shunt resistor at a constant level of 177 mV (typical). The constant-current level can be adjusted by selecting the shunt resistance, RREF. Calculate the typical output current using the equation: IQ,typ = VREF/RREF where VREF is the reference voltage (typically 177 mV) (see Reference Electrical Characteristics). The equation applies for RREF = 0.39 Ω to 10 Ω. The output current is shown as a function of the reference resistance in Figure 1. With the PWM input, the LED brightness can be regulated via duty cycle. Also, PWM = L sets the TL4242 in sleep mode, resulting in a very low current consumption of <1 µA (typical). Due to the high impedance of the PWM input (see Figure 4), the PWM pin also can be used as an enable input. ORDERING INFORMATION (1) PACKAGE (2) TJ –40°C to 150°C (1) (2) QFN – DRJ Reel of 1000 ORDERABLE PART NUMBER TL4242DRJR TOP-SIDE MARKING T4242 For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI web site at www.ti.com. Package drawings, thermal data, and symbolization are available at www.ti.com/packaging. 1 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2008–2009, Texas Instruments Incorporated TL4242 SLVS641A – APRIL 2008 – REVISED MAY 2009 .............................................................................................................................................................. www.ti.com TERMINAL FUNCTIONS NO. NAME DESCRIPTION 1 PWM 2 ST 3 GND Ground 4 REF Reference input. Connect to a shunt resistor. Pulse-width modulation input. If not used, connect to I. Status output. Open-collector output. Connect to an external pullup resistor (RPULLUP ≥ 4.7 kΩ). 5 D Status delay. To set status reaction delay, connect to GND with a capacitor. If no delay is needed, leave open. 6 Q Output 7 NC 8 I Thermal Pad No internal connection Input. Connect directly to GND as close as possible to the device with a 100-nF ceramic capacitor. The thermal pad must be soldered directly to the PCB. It may be connected to ground or left floating. FUNCTIONAL BLOCK DIAGRAM I PWM 8 1 6 Q Bias Supply + − Bandgap Reference 4 REF Comparator 2 ST Status Delay 3 GND 2 Submit Documentation Feedback 5 D Copyright © 2008–2009, Texas Instruments Incorporated TL4242 www.ti.com .............................................................................................................................................................. SLVS641A – APRIL 2008 – REVISED MAY 2009 ABSOLUTE MAXIMUM RATINGS (1) over operating free-air temperature range (unless otherwise noted) MIN MAX –42 45 V D –0.3 7 V PWM –40 40 V REF –1 16 V Q –1 41 V –0.3 Supply voltage range (2) VCC VI Input voltage range VO Output voltage range IO ST Output current range 40 V PWM ±1 mA REF ±2 mA ±5 mA ST θJA Thermal impedance, junction to ambient (3) θJP Thermal impedance, junction to pad (3) TJ Virtual-junction temperature range Tstg Storage temperature range (1) (2) (3) (4) (5) UNIT JESD 51-5 (4) 49.5 JESD 51-7 (5) 114.4 °C/W 4.4 °C/W –40 150 °C –50 150 °C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All voltage values are with respect to the network ground terminal. Maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any allowable ambient temperature is PD = (TJ(max) – TA)/θJA. Operating at the absolute maximum TJ of 150°C can affect reliability. The package thermal impedance is calculated in accordance with JESD 51-5. The package thermal impedance is calculated in accordance with JESD 51-7. RECOMMENDED OPERATING CONDITIONS MIN MAX 4.5 42 V 16 V 0 40 V Status delay (D) capacitance 0 2.2 µF Reference (REF) resistor 0 10 Ω –40 150 °C VCC Supply voltage VST Status (ST) output voltage VPWM PWM voltage CD RREF TJ Virtual-junction temperature UNIT OVERALL DEVICE ELECTRICAL CHARACTERISTICS over recommended operating free-air temperature range, VI = 13.5 V, RREF = 0.47 Ω, VPWM,H, TJ = –40°C to 150°C, all voltages with respect to ground (unless otherwise noted) TYP MAX IqL Supply current PARAMETER VQ = 6.6 V 12 22 mA IqOFF Supply current, off mode PWM = L, TJ < 85°C 0.1 2 µA Copyright © 2008–2009, Texas Instruments Incorporated TEST CONDITIONS MIN Submit Documentation Feedback UNIT 3 TL4242 SLVS641A – APRIL 2008 – REVISED MAY 2009 .............................................................................................................................................................. www.ti.com OUTPUT ELECTRICAL CHARACTERISTICS over recommended operating free-air temperature range, VI = 13.5 V, RREF = 0.47 Ω, VPWM,H, TJ = –40°C to 150°C, all voltages with respect to ground (unless otherwise noted) PARAMETER MIN TYP MAX VQ – VREF (1) = 6.6 V TEST CONDITIONS 357 376 395 VQ – VREF = 6.6 V, RREF = 1 Ω 168 177 185 VQ – VREF = 6.6 V, RREF = 0.39 Ω 431 454 476 VQ – VREF = 5.4 V to 7.8 V, VI = 9 V to 16 V 357 376 395 IQ Output current IQmax Output current limit RREF = 0 Ω 600 Vdr Drop voltage IQ = 300 mA 0.35 (1) UNIT mA mA 0.7 V VQ – VREF equals the forward voltage sum of the connected LEDs (see Figure 3). PWM INPUT ELECTRICAL CHARACTERISTICS over recommended operating free-air temperature range, VI = 13.5 V, RREF = 0.47 Ω, VPWM,H, TJ = –40°C to 150°C, all voltages with respect to ground (unless otherwise noted) PARAMETER VPWM, TEST CONDITIONS High-level PWM voltage MIN TYP MAX 2.6 UNIT V H VPWM, Low-level PWM voltage 0.7 V 500 µA 1 µA L IPWM,H High-level PWM input current VPWM = 5 V IPWM,L Low-level PWM input current VPWM = 0 V tPWM,O Delay time, turn on 70% of IQnom, See Figure 6 0 15 40 µs Delay time, turn off 30% of IQnom, See Figure 6 0 15 40 µs N tPWM,O FF 220 –1 REFERENCE (REF) ELECTRICAL CHARACTERISTICS over recommended operating free-air temperature range, VI = 13.5 V, RREF = 0.47 Ω, VPWM,H, TJ = –40°C to 150°C, all voltages with respect to ground (unless otherwise noted) PARAMETER TEST CONDITIONS VREF Reference voltage RREF = 0.39 Ω to 1 Ω IREF Reference input current VREF = 180 mV MIN TYP MAX UNIT 168 177 185 mV –1 0.1 1 µA STATUS OUTPUT (ST) ELECTRICAL CHARACTERISTICS over recommended operating free-air temperature range, VI = 13.5 V, RREF = 0.47 Ω, VPWM,H, TJ = –40°C to 150°C, all voltages with respect to ground (unless otherwise noted) PARAMETER TEST CONDITIONS VIQL Lower status-switching threshold ST = L VIQH Upper status-switching threshold ST = H VSTL Low-level status voltage IST = 1.5 mA ISTLK Leakage current VST = 5 V MIN TYP 15 25 30 MAX UNIT mV 40 mV 0.4 V 5 µA STATUS DELAY (D) ELECTRICAL CHARACTERISTICS over recommended operating free-air temperature range, VI = 13.5 V, RREF = 0.47 Ω, VPWM,H, TJ = –40°C to 150°C, all voltages with respect to ground (unless otherwise noted) PARAMETER TEST CONDITIONS tSTHL Delay time, status reaction CD = 47 nF, ST H→L tSTLH Delay time, status release CD = 47 nF, ST L→H 4 Submit Documentation Feedback MIN TYP MAX 6 10 14 UNIT ms 10 20 µs Copyright © 2008–2009, Texas Instruments Incorporated TL4242 www.ti.com .............................................................................................................................................................. SLVS641A – APRIL 2008 – REVISED MAY 2009 TYPICAL CHARACTERISTICS 450 700 400 600 IOUT – Output Current – mA IOUT – Output Current – mA 350 500 400 300 200 250 200 150 100 50 100 0 -50 0 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 0 2.25 10 15 20 25 30 35 VCC – Supply Voltage – V Figure 1. Output Current vs External Resistor Figure 2. Output Current vs Supply Voltage 40 60 50 IPWM – PWM Current – µA 178.0 177.5 177.0 176.5 176.0 175.5 -40 5 RREF – 8W 178.5 VREF – Reference Voltage – mV 300 40 30 20 10 0 -10 -20 0 20 40 60 80 100 120 140 TJ – Virtual Junction Temperature – °C Figure 3. Reference Voltage vs Junction Temperature Copyright © 2008–2009, Texas Instruments Incorporated 0 10 20 30 40 VPWM – PWM Voltage – V Figure 4. PWM Pin Input Current vs PWM Voltage Submit Documentation Feedback 5 TL4242 SLVS641A – APRIL 2008 – REVISED MAY 2009 .............................................................................................................................................................. www.ti.com APPLICATION INFORMATION Figure 5 shows a typical application with the TL4242 LED driver. The three LEDs are driven by a supply current that is adjusted by the resistor, RREF, preventing brightness variations due to forward voltage spread of the LEDs. The luminosity spread arising from the LED production process can be compensated via software by an appropriate duty cycle applied to the PWM pin. Therefore, it is not necessary to select LEDs for forward voltage or luminosity classes. The minimum supply voltage calculates as the sum of the LED forward voltages, the TL4242 drop voltage (maximum 0.7 V at a LED current of 300 mA) and the maximum voltage drop at the shunt resistor RREF of 185 mV (max). VBAT I RO SI Microcontroller Q RADJ GND 10 µF D 10 kΩ 100 nF PWM ST I Q TL4242 REF GND LED Dragon D 47 nF 0.47 Ω 0.25 W RREF Figure 5. Application Circuit The status output of the LED driver (ST) detects an open-load condition, enabling supervision of correct LED operation. An LED failure is detected as a voltage drop at the shunt resistor (RREF) below 25 mV (typ). In this case, the status output pin (ST) is set low after a delay time adjustable by an optional capacitor connected to pin D. The functionality and timing of ST and PWM are shown in Figure 6. The status delay can be adjusted via the capacitor connected to pin D. Delay time scales linearly with capacitance, CD: 6 Submit Documentation Feedback Copyright © 2008–2009, Texas Instruments Incorporated TL4242 www.ti.com .............................................................................................................................................................. SLVS641A – APRIL 2008 – REVISED MAY 2009 t STHL,typ + CD 47 nF 10 ms t STLH,typ + CD 47 nF 10 ms Open Load VPWM Open Load VPWM,H VPWM,L IQ t tPWM,ON tPWM,OFF IQ,nom 70% 30% t VD tSTHL VLD t VST t Figure 6. Function and Timing Diagram Copyright © 2008–2009, Texas Instruments Incorporated Submit Documentation Feedback 7 PACKAGE OPTION ADDENDUM www.ti.com 23-Jan-2009 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing TL4242DRJR ACTIVE SON DRJ Pins Package Eco Plan (2) Qty 8 1000 Green (RoHS & no Sb/Br) Lead/Ball Finish CU NIPDAU MSL Peak Temp (3) Level-3-260C-168 HR (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. 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Addendum-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 2-Sep-2009 TAPE AND REEL INFORMATION *All dimensions are nominal Device TL4242DRJR Package Package Pins Type Drawing SON DRJ 8 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 1000 180.0 12.4 Pack Materials-Page 1 4.25 B0 (mm) K0 (mm) P1 (mm) 4.25 1.15 8.0 W Pin1 (mm) Quadrant 12.0 Q2 PACKAGE MATERIALS INFORMATION www.ti.com 2-Sep-2009 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TL4242DRJR SON DRJ 8 1000 190.5 212.7 31.8 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. 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