Sample & Buy Product Folder Support & Community Tools & Software Technical Documents Reference Design LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 LM3414/HV 1-A, 60-W Common Anode-Capable Constant Current Buck LED Driver Requires No External Current Sensing Resistor 1 Features * 1 * * * * * * * * * * * 3 Description (1) Supports LED Power up to 60 W : 18x 3-W HBLEDs Requires No External Current Sensing Resistor 3% LED Current Accuracy Up to 96% Efficiency High Contrast Ratio (Minimum Dimming Current Pulse Width <10 S) Integrated Low-Side N-Channel MOSFET Adjustable Constant LED Current From 350 mA to 1000 mA Support Analog Dimming and Thermal Fold-Back Wide Input Voltage Range: - 4.5 V to 42 V (LM3414) - 4.5 V to 65 V (LM3414HV) Constant Switching Frequency Adjustable from 250 kHz to 1000 kHz Thermal Shutdown Protection Power Enhanced SOIC-8 or 3 mm x 3 mm WSON-8 Package The LM3414 and LM3414HV are 1-A 60-W(1) common anode-capable constant current buck LED drivers. They are suitable for driving single string of 3W HBLED with up to 96% efficiency. They accept input voltages from 4.5 VDC to 65 VDC and deliver up to 1-A average LED current with 3% accuracy. The integrated low-side N-channel power MOSFET and current sensing element realize simple and low component count circuitry, as no bootstrapping capacitor and external current-sensing resistor are required. An external small-signal resistor to ground provides very fine LED current adjustment, analog dimming, and thermal fold-back functions. Constant switching frequency operation eases EMI. No external loop compensation network is needed. The proprietary Pulse-Level-Modulation (PLM) control method benefits in high conversion efficiency and true average LED current regulation. Fast response time realizes fine LED current pulse fulfilling the 240 Hz 256-step dimming resolution requirement for general lighting. The LM3414 and LM3414HV are available in SOIC-8 and 3 mm x 3 mm WSON-8 packages. 2 Applications * * * * Device Information(2) High Power LED Drivers Architectural Lighting, Office Troffers Automotive Lighting MR-16 LED Lamps PART NUMBER LM3414, LM3414HV PACKAGE BODY SIZE (NOM) WSON (8) 3.00 mm x 3.00 mm SOIC (8) 3.90 mm x 4.89 mm (1) Thermal derating applies according to actual operation conditions. (2) For all available packages, see the orderable addendum at the end of the data sheet. Simplified Application Schematic High power LED Array Vin D1 LM3414/14HV CVCC VCC PGND VIN 4.5V 42 VDC (LM3414) Iout = 1A CIN 4.5V 65 VDC (LM3414HV) GND L1 LX IADJ DIM GND FS PWM dimming signal GND RIADJ * DAP connect to GND RFS GND GND 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 4 4 4 5 5 6 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description .............................................. 9 7.1 Overview ................................................................... 9 7.2 Functional Block Diagram ......................................... 9 7.3 Feature Description................................................. 10 7.4 Device Functional Modes........................................ 15 8 Application and Implementation ........................ 16 8.1 Application Information............................................ 16 8.2 Typical Applications ................................................ 18 9 Power Supply Recommendations...................... 22 10 Layout................................................................... 22 10.1 Layout Guidelines ................................................. 22 10.2 Layout Example .................................................... 22 11 Device and Documentation Support ................. 23 11.1 11.2 11.3 11.4 11.5 Related Links ........................................................ Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 23 23 23 23 23 12 Mechanical, Packaging, and Orderable Information ........................................................... 23 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision E (May 2013) to Revision F Page * Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section. ................................................................................................. 1 * Removed soldering information. ............................................................................................................................................. 4 Changes from Revision D (April 2013) to Revision E * 2 Page Changed layout of National Data Sheet to TI format ........................................................................................................... 14 Submit Documentation Feedback Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV LM3414, LM3414HV www.ti.com SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 5 Pin Configuration and Functions DDA Package 8-Pin SOIC Top View NGQ Package 8-Pin WSON Top View VCC 1 8 VIN PGND 2 7 LX IADJ 3 6 DIM GND 4 5 FS EP VCC 1 8 VIN PGND 2 7 LX IADJ 3 6 DIM 5 FS GND EP 4 Pin Functions PIN NAME NO. I/O DESCRIPTION VCC 1 O Internal Regulator Output Pin. This pin should be bypassed to ground by a ceramic capacitor with a minimum value of 1 F. PGND 2 -- Power Ground Pin. Ground for power circuitry. Reference point for all stated voltages. Must be externally connected to EP and GND. IADJ 3 I Average Output Current Adjustment Pin. Connect resistor RIADJ from this pin to ground to adjust the average output current. GND 4 -- Analog Ground Pin. Analog ground connection for internal circuitry, must be connected to PGND external to the package. FS 5 I Switching Frequency Setting Pin. Connect resistor RFS from this pin to ground to set the switching frequency. DIM 6 I PWM Dimming Control Pin. Apply logic level PWM signal to this pin controls the intend brightness of the LED string. LX 7 O Drain of N-MOSFET Switch. Connect this pin to the output inductor and anode of the schottky diode. VIN 8 I Input Voltage Pin. The input voltage should be in the range of 4.5 V to 42 V (LM3414) or 4.5 V to 65 V (LM3414HV). EP EP -- Thermal Pad (Power Ground). Used to dissipate heat from the package during operation. Must be electrically connected to PGND external to the package. Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV Submit Documentation Feedback 3 LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) VIN to GND VIN to GND (Transient) MIN MAX LM3414 -0.3 42 LM3414HV -0.3 65 LM3414 45 (500 ms) LM3414HV 67 (500 ms) UNIT V V LM3414 -0.3 42 LM3414HV -0.3 65 LM3414 -3 (2 ns) 45 (500 ms) LM3414HV -3 (2 ns) 67 (500 ms) FS, IADJ to GND -0.3 5 DIM to GND -0.3 6 V Storage Temperature -65 125 C LX to PGND LX to PGND (Transient) (1) V V V Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 6.2 ESD Ratings VALUE UNIT WSON PACKAGE V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) (2) 2000 Charged-device model (CDM), per JEDEC specification JESD22C101 (3) 750 Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) (2) 2000 Charged-device model (CDM), per JEDEC specification JESD22C101 (3) 750 V SOIC PACKAGE V(ESD) (1) (2) (3) Electrostatic discharge V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. The human body model is a 100pF capacitor discharged through a 1.5 k resistor into each pin. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN VIN Submit Documentation Feedback MAX 4.5 42 LM3414HV 4.5 65 -40 125 Junction temperature 4 NOM LM3414 UNIT V C Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV LM3414, LM3414HV www.ti.com SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 6.4 Thermal Information LM3414, LM3414HV THERMAL METRIC (1) NGQ (WSON) DDA (SOIC-8) 8 PINS 8 PINS UNIT RJA Junction-to-ambient thermal resistance 47.7 50.5 C/W RJC(top) Junction-to-case (top) thermal resistance 43.1 55.7 C/W RJB Junction-to-board thermal resistance 22.3 28.6 C/W JT Junction-to-top characterization parameter 0.4 9.5 C/W JB Junction-to-board characterization parameter 22.5 28.5 C/W RJC(bot) Junction-to-case (bottom) thermal resistance 4 3.2 C/W (1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953. 6.5 Electrical Characteristics MIN and MAX limits apply for TJ = -40C to 125C unless specified otherwise. VIN = 24 V unless otherwise indicated. PARAMETER TEST CONDITIONS MIN (1) TYP (2) MAX (1) UNIT SYSTEM PARAMETERS - LM3414 IIN-DIM-HIGH Operating Current 4.5 V Vin 42 V RIADJ = 3.125 k VDIM = High 2.2 3.2 3.5 mA IIN-DIM-LOW Standby Current 4.5 V Vin 42 V RIADJ = 3.125 k VDIM = Low 0.8 1.15 1.4 mA ILX-OFF LX Pin Current Main Switch Turned OFF VLX = VIN = 42 V 6 A SYSTEM PARAMETERS - LM3414HV IIN-DIM-HIGH Operating Current 4.5 V Vin 65 V RIADJ = 3.125 k VDIM = High 2.2 3.3 3.6 mA IIN-DIM-LOW Standby Current 4.5 V Vin 65 V RIADJ = 3.125 k VDIM = Low 0.8 1.2 1.45 mA ILX-OFF LX Pin Current Main Switch Turned OFF VLX = VIN= 65 V 6.5 A SYSTEM PARAMETERS - LM3414/3414HV ILED Average LED Current VCC-UVLO Vcc UVLO Threshold VCC-UVLO-HYS Vcc UVLO Hysteresis VIADJ IADJ Pin voltage VDIM DIM Pin Threshold VDIM-HYS DIM Pin Hysteresis fSW Switching frequency fSW-TOL Switching frequency tolerance tON-MIN Minimum on-time (1) (2) RIADJ = 3.125 k TA = 25C 0.97 1 1.03 A RIADJ = 3.125 k TA = -40C to 125C 0.95 1 1.05 A 3.6 3.75 3.9 VCC Decreasing, TA = 25C 300 1.23 VDIM Increasing 1.255 1.280 1 1.2 100 RFS = 40 k V mV V V mV 250 500 1000 kHz 420 500 580 kHz 400 ns All limits specified at room temperature (TYP) and at temperature extremes (MIN/MAX). All room temperature limits are 100% production tested. All limits at temperature extremes are specified through correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL). Typical specification represent the most likely parametric norm at 25C operation. Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV Submit Documentation Feedback 5 LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 www.ti.com Electrical Characteristics (continued) MIN and MAX limits apply for TJ = -40C to 125C unless specified otherwise. VIN = 24 V unless otherwise indicated. MIN (1) TYP (2) MAX (1) CVCC = 1 F, No Load to IVCC = 2 mA 4.7 5.4 6 VIN = 4.5 V, 2-mA Load 3.8 4.2 PARAMETER TEST CONDITIONS UNIT INTERNAL VOLTAGE REGULATOR VCC regulator output voltage (3) VCC V V MAIN SWITCH RLX Resistance across LX and GND Main Switch Turned ON 1.8 THERMAL PROTECTION TSD Thermal shutdown temperature TJ Rising 170 C TSD-HYS Thermal shutdown temperature hysteresis TJ Falling 10 C (3) VCC provides self bias for the internal gate drive and control circuits. Device thermal limitations limit external loading to the pin. 6.6 Typical Characteristics All curves taken at VIN = 48 V with configuration in typical application for driving twelve power LEDs with ILED = 1 A shown in this data sheet. TA = 25C, unless otherwise specified. 6 Figure 1. IOUT vs VIN, (4 - 8 LED), LM3414HV Figure 2. IOUT vs VIN, (10 - 18 LED), LM3414HV Figure 3. Efficiency vs VIN, (4 - 8 LED), LM3414HV Figure 4. Efficiency vs VIN, (10 - 18 LED), LM3414HV Submit Documentation Feedback Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV LM3414, LM3414HV www.ti.com SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 Typical Characteristics (continued) All curves taken at VIN = 48 V with configuration in typical application for driving twelve power LEDs with ILED = 1 A shown in this data sheet. TA = 25C, unless otherwise specified. Figure 5. IOUT vs Temperature (TA) (6 LED, VIN = 24 V), LM3414HV Figure 6. IOUT vs Temperature (TA) (12 LED, VIN = 48 V), LM3414HV Figure 7. VCC vs Temperature (TA), LM3414HV Figure 8. VIADJ vs Temperature (TA), LM3414HV Figure 9. IOUT and VLX, LM3414HV Figure 10. ILX and VDIM, LM3414HV Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV Submit Documentation Feedback 7 LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 www.ti.com Typical Characteristics (continued) All curves taken at VIN = 48 V with configuration in typical application for driving twelve power LEDs with ILED = 1 A shown in this data sheet. TA = 25C, unless otherwise specified. Figure 11. LED Current With PWM Dimming (VDIM Rising), LM3414HV Figure 12. LED Current With PWM Dimming (VDIM Falling), LM3414HV Figure 13. LED Current With PWM Dimming (9-s dimming pulse), LM3414HV 8 Submit Documentation Feedback Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV LM3414, LM3414HV www.ti.com SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 7 Detailed Description 7.1 Overview The LM3414/HV is a high power floating buck LED driver with wide input voltage ranges. The device requires no external current sensing elements and loop compensation networks. The integrated power N-MOSFET enables high-output power with up to 1000-mA output current. The combination of Pulse Width Modulation (PWM), control architecture, and the proprietary Pulse Level Modulation (PLM) ensures accurate current regulation, good EMI performance, and provides high flexibility on inductor selection. High-speed dimming control input allows precision and high resolution brightness control for applications require fine brightness adjustment. 7.2 Functional Block Diagram Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV Submit Documentation Feedback 9 LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 www.ti.com 7.3 Feature Description 7.3.1 Pulse-Level-Modulation (PLM) Operation Principles The main control circuitry of the LM3414/HV is generally a Pulse-Width-Modulated (PWM) controller with the incorporation of the Pulse-Level-Modulation (PLM) technology. PLM is a technology that facilitates true output average current control without the need to sense the output current directly. In the LM3414/LM3414HV, the PLM circuit senses the current of the internal switch through integrated current sensing circuitry to realize average output current control. The use of PLM reduces the current sensing power losses as it needs current information only when the switch is turned ON. For proper operation of this control scheme, the converter must operate in CCM (continuous conduction mode), so the switching frequency and inductor value must be chosen to prevent the inductor current reaching 0 A during the switch OFF time each cycle. In general, for the LED drivers with current sensing resistor at the output, the power dissipation on the current sensing resistor is ILED2 x RISNS, where ILED is the average output current and RISNS is the resistance of the current sensing resistor. In the LM3414/LM3414HV, power dissipates on the internal RISNS only during ON period of the internal power switch. The power loss on RISNS(internal) becomes ILED2 x RISNS x D, where D is the switching duty cycle. For example, when the switching duty cycle, D of a converter is 0.5, the power loss on RISNS with PLM is half of those with conventional output current sensing resulting in increased efficiency. The Pulse-Level-Modulation is a patented method to ensure accurate average output current regulation without the need of direct output current sensing. Figure 14 shows the current waveforms of a typical buck converter under steady state, where, IL1 is the inductor current and ILX is the main switch current flowing into the LX pin. For a buck converter operating in steady state, the mid-point of the RAMP section of the main switch current is equal to the average level of the inductor current-hence the average output current. In short, by regulating the mid-point of the RAMP section of the main switch current with respect to a precise reference level, PLM achieves output current regulation by sensing the main switch current solely. IL1 ILED = IL(AVERAGE) = Mid-point of ILX during tON ILX ILED Time 1/fSW tON Figure 14. Waveforms of a Floating Buck LED Driver With PLM 7.3.2 Minimum Switch ON-time As the LM3414 features a 400 ns minimum ON time, it is essential to make sure the ON time of the internal switch is not shorter than 400 ns when setting the LED driving current. If the switching ON time is shorter than 400 ns, the accuracy of the LED current may not maintain and exceed the rated current of the LEDs. The ratio of the LED forward voltage to input voltage is restricted by the following restriction, as shown in Equation 1. VLED t 400 nS x fSW VIN 10 Submit Documentation Feedback (1) Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV LM3414, LM3414HV www.ti.com SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 Feature Description (continued) 7.3.3 Peak Switch Current Limit The LM3414/HV features an integrated switch current limiting mechanism that protects the LEDs from being overdriven. The switch current limiter triggers when the switch current exceeds three times the current level set by RIADJ. Once the current limiter is triggered, the internal power switch turns OFF for 3.6 s to allow the inductor to discharge and cycles repetitively until the overcurrent condition is removed. The current limiting feature is exceptionally important to avoid permanent damage of the LM3414/HV application circuit due to short circuit of LED string. 7.3.4 PWM Dimming Control The DIM pin of the LM3414/HV is an input with internal pullup that accepts logic signals for average LED current control. Applying a logic high (greater than 1.2 V) signal to the DIM pin or leaving the DIM pin open will enable the device. Applying a logic low signal (less than 0.9 V) to the DIM pin will disable the switching activity of the device but maintain VCC regulator active. The LM3414/HV allows the inductor current to slew up to the preset regulated level at full speed instead of charging the inductor with multiple restrained switching duty cycles. This enables the LM3414/HV to achieve high-speed dimming and very fine dimming control as shown in Figure 15 and Figure 16. LE D cu rre nt s le ws up ILED ILED regulated Time 0 LED dimmed OFF ILED slew up time Figure 15. LED Current Slew Up With Multiple Switching Cycle Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV Submit Documentation Feedback 11 LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 www.ti.com Feature Description (continued) LED c urrent s lews u p ILED ILED regulated Time 0 LED dimmed OFF ILED slew up time Figure 16. Shortened Current Slew Up Time of the LM3414/HV To ensure normal operation of the LM3414/HV, TI recommends setting the dimming frequency not higher than 1/10 of the switching frequency. The minimum dimming duty cycle is limited by the 400 ns minimum ON time. In applications that require high dimming contrast ratio, low dimming frequency should be used. 7.3.5 Analog Dimming Control The IADJ pin can be used as an analog dimming signal input. As the average output current of the LM3414 depends on the current being drawn from the IADJ pin, thus the LED current can be increased or decreased by applying external bias current to the IADJ pin. The simplified circuit diagram for facilitating analog dimming is as shown in Figure 17. The minimum LED current for analog dimming is 100 mA and the converter must remain in continuous conduction mode (CCM). The switching frequency and inductor value must be sized accordingly. 12 Submit Documentation Feedback Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV LM3414, LM3414HV www.ti.com SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 Feature Description (continued) VCC Current Mirror VEXT To LED current setting circuitry + - IEXT + - IADJ IIADJ 1.255V RIADJ LM3414/14HV Figure 17. Analog LED Current Control Circuit When external bias current IEXT is applied to the IADJ pin, the reduction of LED current follows Equation 2 through Equation 3. 1.255 - IEXT x 2490 x 103 mA RIADJ ILED = (2) Provided that IEXT < 1.255 RIADJ (3) ILED decreases linearly as IEXT increases. This feature is exceptionally useful for the applications with analog dimming control signals such as those from analog temperature sensors and ambient light sensors. Figure 18 shows an example circuit for analog dimming control using simple external biasing circuitry with a variable resistor. Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV Submit Documentation Feedback 13 LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 www.ti.com Feature Description (continued) VCC VCC IEXT Q1 IADJ R2 R1 LM3414 RIADJ VR1 GND GND GND Figure 18. Example Analog Dimming Control Circuit In Figure 18, the variable resistor VR1 controls the base voltage of Q1 and eventually adjusts the bias voltage of current to the IADJ pin (IEXT). As the resistance of VR1 increases and the voltage across VR1 exceeds 1.255 V + 0.7 V, the LED current starts to decrease as IEXT increases. Where VCC 1.955 IEXT = R2 R1 +1 VR1 mA R1 +1 VR1 (4) The analog dimming begins only when IEXT > 0. D1 LM3414 / LM3414HV CVCC VCC R1 PGND IADJ GND GND Q1 Analog temperature sensor GND VIN U1 GND CIN GND LX PWM dimming signal DIM FS * DAP connect to GND R2 L1 High power LED Array Vin VCC RFS GND RIADJ GND Figure 19. Application Circuit of LM3414/HV With Temperature Fold-Back Circuitry and PWM Dimming 14 Submit Documentation Feedback Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV LM3414, LM3414HV www.ti.com SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 Feature Description (continued) 7.3.6 Internal VCC Regulator The LM3414/HV features a 5.4-V internal voltage regulator that connects between the VIN and VCC pins for powering internal circuitry and provide biases to external components. The VCC pin must be bypassed to the GND pin with a 1-F ceramic capacitor, CVCC that connected to the pins as close as possible. When the input voltage falls to less than 6 V, the VCC voltage will drop to less than 5.4 V and decrease proportionally as Vin decreases. The device will shutdown as the VCC voltage falls to less than 3.9 V. When the internal regulator is used to provide bias to external circuitry, it is essential to ensure the current sinks from VCC pin does not exceed 2 mA to maintain correct voltage regulation. 7.4 Device Functional Modes There are no additional functional modes for this device. Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV Submit Documentation Feedback 15 LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 www.ti.com 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI's customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information 8.1.1 Setting the Switching Frequency Both the LM3414 and LM3414HV are PWM LED drivers that contain a clock generator to generate constant switching frequency for the device. The switching frequency is determined by the resistance of an external resistor RFS in the range of 250 kHz to 1 MHz. Lower resistance of RFS results in higher switching frequency. The switching frequency of the LM3414/HV is governed using Equation 5. fSW = 20 x 106 kHz RFS (5) 1000 SW (kHz) 800 600 400 200 20 40 RFS (k) 60 80 Figure 20. Switching Frequency vs RFS Table 1. Examples for fSW Settings fSW (kHz) RFS (k) 250 80 500 40 1000 20 To ensure accurate current regulation, the LM3414/HV should be operated in continuous conduction mode (CCM) and the ON time should not be shorter than 400 ns under all operation condition. 8.1.2 Setting LED Current The LM3414/HV requires no external current sensing resistor for LED current regulation. The average output current of the LM3414/HV is adjustable by varying the resistance of the resistor, RIADJ that connects across the IADJ and GND pins. The IADJ pin is internally biased to 1.255 V. The LED current is then governed by Equation 6. ILED = 3125 x 103 mA RIADJ where * 16 350 mA < ILED < 1A Submit Documentation Feedback (6) Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV LM3414, LM3414HV www.ti.com SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 1.4 1.2 ILED(A) 1.0 0.8 0.6 0.4 0.2 0.0 0 1 2 3 4 5 6 RIADJ(k ) 7 8 9 Figure 21. LED Current vs RIADJ Table 2. Examples for IOUT Settings IOUT (mA) RIADJ (k) 350 8.93 500 6.25 700 4.46 1000 3.13 The LED current can be set to any level in the range from 350 mA to 1A. To provide accurate LED current, RIADJ should be a resistor with no more than 0.5% tolerance. If the IADJ pin is accidentally shorted to GND (RIADJ = 0), the output current is limited to avoid damaging the circuit. When the overcurrent protection is activated, current regulation cannot be maintained until the overcurrent condition is cleared. 8.1.3 Inductor Selection To ensure proper output current regulation, the LM3414/HV must operate in Continuous Conduction Mode (CCM). With the incorporation of PLM, the peak-to-peak inductor current ripple can be set as high as 60% of the defined average output current. The minimum inductance of the inductor is decided by the defined average LED current and allowable inductor current ripple. The minimum inductance can be found by the equations shown in Equation 7 through Equation 8. Because: 'IL = VIN - VLED xDxT L (7) Thus: LMIN = VIN -VLED VLED 1 x x 1.2 x ILED VIN fSW (8) The LM3414/HV can maintain LED current regulation without output filter capacitor. This is because the inductor of the floating buck structure provides continuous current to the LED throughout the entire switching cycle. When LEDs are driven without filter capacitor, the LED peak current must not set exceeding the rated current of the LED. The peak LED current is governed by Equation 9. 'IL = (VIN -VLED) VLED + ILED(AVG) 2L x VIN x fSW (9) Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV Submit Documentation Feedback 17 LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 www.ti.com 8.2 Typical Applications 8.2.1 LM3414/HV Design Example Vin High power LED Array D1 LM3414/14HV CVCC VCC VIN PGND 4.5V 42 VDC (LM3414) Iout = 1A CIN 4.5V 65 VDC (LM3414HV) GND L1 LX IADJ DIM GND FS PWM dimming signal GND RIADJ * DAP connect to GND RFS GND GND Figure 22. LM3414/HV Design Example Schematic 8.2.1.1 Design Requirements * Input Voltage: VIN * LED String Voltage: VLED * LED Current: ILED * Switching Frequency: fSW * Maximum LED Current Ripple: iL-PP * Maximum Input Voltage Ripple: VIN 8.2.1.2 Detailed Design Procedure 8.2.1.2.1 Calculate Operating Parameters To calculate component values the operating duty cycle (D) must be calculated using Equation 10. D= VLED VIN (10) 8.2.1.2.2 Calculate RIADJ To get the desired LED current calculate the value for RIADJ using Equation 11. RIADJ = 3125 ILED (11) 8.2.1.2.3 Calculate RFS Calculate the value of RFS for the desired switching frequency using Equation 12. RFS = 18 20 x 109 fSW Submit Documentation Feedback (12) Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV LM3414, LM3414HV www.ti.com SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 Typical Applications (continued) 8.2.1.2.4 Calculate LMIN Calculate the minimum inductor value required for the desired LED current ripple using Equation 13. LMIN = :VIN - VLED; x VLED fSW x VIN x iL-PP (13) 8.2.1.2.5 Calculate CIN-MIN Calculate the minimum input capacitor value for the desired input voltage ripple using Equation 14. CIN-MIN = D x :1 -D; x ILED fSW x VIN (14) 8.2.2 LM3414/HV Design Example (IOUT = 1 A) Vin Iout = 1000 mA (nom.) 100V 2.2 PF CIN CVCC 16V 1 PF LM3414 / LM3414HV VCC VIN PGND IADJ 100V 2A LED x 6 D1 24V 42 VDC (LM3414) 24V - 65 VDC (LM3414HV) GND L1 47 PH LX U1 GND DIM FS GND RIADJ 3.24k * DAP connect to GND GND RFS 40.2k GND Figure 23. LM3414/HV Design Example (IOUT = 1 A) Schematic 8.2.2.1 Design Requirements * Input Voltage: VIN = 48 V 10% * LED String Voltage: VLED = 35 V * LED Current: ILED = 1 A * Switching Frequency: fSW = 500 kHz * Maximum LED Current Ripple: iL-PP 500 mA * Maximum Input Voltage Ripple: VIN 200 mV 8.2.2.2 Detailed Design Procedure 8.2.2.2.1 Calculate Operating Parameters To calculate component values the operating duty cycle (D) for this application can be calculated be calculated using Equation 15. D= VLED 35V = = 0.73 48V VIN (15) 8.2.2.2.2 Calculate RIADJ For 1A LED current calculate the value for RIADJ using Equation 16. Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV Submit Documentation Feedback 19 LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 www.ti.com Typical Applications (continued) RIADJ = 3125 3125 = = 3.125k ILED 1A (16) Choose a standard value of RIADJ = 3.24k. 8.2.2.2.3 Calculate RFS Calculate the value of RFS for 500-kHz switching frequency using Equation 17. RFS 20 x 109 20 x 109 = = = 40k fSW 500kHz (17) Choose a standard value of RFS = 40.2k. 8.2.2.2.4 Calculate LMIN Calculate the minimum inductor value required for 500 mA or less peak-to-peak LED current ripple using Equation 18. LMIN = :VIN - VLED; x VLED :48V - 35V; x 35V = 500kHz x 35V x 500mA fSW x VIN x iL-PP H (18) Choose a higher standard value of L = 47H. 8.2.2.2.5 Calculate CIN-MIN Calculate the minimum input capacitor value for 200 mV or less input voltage ripple using Equation 19. CIN-MIN = D x :1 -D; x ILED 0.73 x :1 - 0.73; x 1A = fSW x VIN 500kHz x 200mV F (19) Choose a higher standard value of CIN = 2.2F. Table 3. Bill of Materials DESIGNATION 20 DESCRIPTION PACKAGE MANUFACTURE PART NO. VENDOR U1 LED Driver IC LM3414 / LM3414HV SOIC-8 LM3414 / LM3414HV TI L1 Inductor 47 H 8 x 8 x 4.9 (mm) MMD-08EZ-470M-SI Mag.Layers D1 Schottky Diode 100 V, 2 A SMP SS2PH10-M3 Vishay CIN Cap MLCC 100V 2.2 F X7R 1210 GRM32ER72A225KA35L Murata CVCC Cap MLCC 16V 1 F X5R 603 GRM39X5R105K16D52K Murata RIADJ Chip Resistor 3.24 k 1% 603 CRCW06033241F Vishay RFS Chip Resistor 40.2 k 1% 603 CRCW06034022F Vishay Submit Documentation Feedback Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV LM3414, LM3414HV www.ti.com SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 8.2.2.3 Application Curve Figure 24. PWM Dimming Top = DIM. Bottom = LED Current. Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV Submit Documentation Feedback 21 LM3414, LM3414HV SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 www.ti.com 9 Power Supply Recommendations Use any DC output power supply with a maximum voltage high enough for the application. The power supply should have a minimum current limit of at least 1 A. 10 Layout 10.1 Layout Guidelines Discontinuous currents are the most likely to generate EMI; therefore, take care when routing these paths. The main path for discontinuous current in the LM3414/HV buck converter contains the input capacitor (CIN), the recirculating diode (D1), and the switch node (LX). This loop should be kept as small as possible and the connections between all three components should be short and thick to minimize parasitic inductance. In particular, the switch node (where L1, D1 and LX connect) should be just large enough to connect the components without excessive heating from the current it carries. The IADJ, FS, and DIM pins are all high-impedance control inputs which couple external noise easily, therefore the loops containing these high impedance nodes should be minimized. The frequency setting resistor (RFS) and current setting resistor (RIADJ) should be placed close to the FS and IADJ pins as possible. 10.2 Layout Example + GND VIN/LED+ CIN VCC VIN D1 CVCC LED- RIADJ LX IADJ DIM GND FS L1 - PGND RFS THERMAL/POWER VIA Figure 25. Layout Recommendation 22 Submit Documentation Feedback Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV LM3414, LM3414HV www.ti.com SNVS678F - JUNE 2010 - REVISED NOVEMBER 2015 11 Device and Documentation Support 11.1 Related Links The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy. Table 4. Related Links PARTS PRODUCT FOLDER SAMPLE AND BUY TECHNICAL DOCUMENTS TOOLS AND SOFTWARE SUPPORT AND COMMUNITY LM3414 Click here Click here Click here Click here Click here LM3414HV Click here Click here Click here Click here Click here 11.2 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2ETM Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 11.3 Trademarks E2E is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. 11.4 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 11.5 Glossary SLYZ022 -- TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. Copyright (c) 2010-2015, Texas Instruments Incorporated Product Folder Links: LM3414 LM3414HV Submit Documentation Feedback 23 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (C) Device Marking (3) (4/5) (6) LM3414HVMR/NOPB ACTIVE SO PowerPAD DDA 8 95 RoHS & Green SN Level-3-260C-168 HR -40 to 125 L3414 HVMR LM3414HVMRX/NOPB ACTIVE SO PowerPAD DDA 8 2500 RoHS & Green SN Level-3-260C-168 HR -40 to 125 L3414 HVMR LM3414HVSD/NOPB ACTIVE WSON NGQ 8 1000 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 L249B LM3414HVSDX/NOPB ACTIVE WSON NGQ 8 4500 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 L249B LM3414MR/NOPB ACTIVE SO PowerPAD DDA 8 95 RoHS & Green SN Level-3-260C-168 HR -40 to 125 L3414 MR LM3414MRX/NOPB ACTIVE SO PowerPAD DDA 8 2500 RoHS & Green SN Level-3-260C-168 HR -40 to 125 L3414 MR LM3414SD/NOPB ACTIVE WSON NGQ 8 1000 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 L248B LM3414SDX/NOPB ACTIVE WSON NGQ 8 4500 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 L248B (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) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two lines if the finish value exceeds the maximum column width. 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. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 26-Jun-2015 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LM3414HVMRX/NOPB SO Power PAD DDA 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LM3414HVSD/NOPB WSON NGQ 8 1000 178.0 12.4 3.3 3.3 1.0 8.0 12.0 Q1 LM3414HVSDX/NOPB WSON NGQ 8 4500 330.0 12.4 3.3 3.3 1.0 8.0 12.0 Q1 LM3414MRX/NOPB SO Power PAD DDA 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LM3414SD/NOPB WSON NGQ 8 1000 178.0 12.4 3.3 3.3 1.0 8.0 12.0 Q1 LM3414SDX/NOPB WSON NGQ 8 4500 330.0 12.4 3.3 3.3 1.0 8.0 12.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 26-Jun-2015 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM3414HVMRX/NOPB LM3414HVSD/NOPB SO PowerPAD DDA 8 2500 367.0 367.0 35.0 WSON NGQ 8 1000 210.0 185.0 35.0 LM3414HVSDX/NOPB WSON NGQ 8 4500 367.0 367.0 35.0 LM3414MRX/NOPB SO PowerPAD DDA 8 2500 367.0 367.0 35.0 LM3414SD/NOPB WSON NGQ 8 1000 210.0 185.0 35.0 LM3414SDX/NOPB WSON NGQ 8 4500 367.0 367.0 35.0 Pack Materials-Page 2 PACKAGE OUTLINE DDA0008A PowerPAD TM SOIC - 1.7 mm max height SCALE 2.400 PLASTIC SMALL OUTLINE C 6.2 TYP 5.8 SEATING PLANE PIN 1 ID AREA A 0.1 C 6X 1.27 8 1 2X 3.81 5.0 4.8 NOTE 3 4 5 B 8X 4.0 3.8 NOTE 4 0.51 0.31 0.25 1.7 MAX C A B 0.25 TYP 0.10 SEE DETAIL A 5 4 EXPOSED THERMAL PAD 0.25 GAGE PLANE 2.34 2.24 8 1 0 -8 0.15 0.00 1.27 0.40 DETAIL A 2.34 2.24 TYPICAL 4218825/A 05/2016 PowerPAD is a trademark of Texas Instruments. NOTES: 1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing per ASME Y14.5M. 2. This drawing is subject to change without notice. 3. This dimension does not include mold flash, protrusions, or gate burrs. Mold flash, protrusions, or gate burrs shall not exceed 0.15 mm per side. 4. This dimension does not include interlead flash. Interlead flash shall not exceed 0.25 mm per side. 5. Reference JEDEC registration MS-012. www.ti.com EXAMPLE BOARD LAYOUT DDA0008A PowerPAD TM SOIC - 1.7 mm max height PLASTIC SMALL OUTLINE (2.95) NOTE 9 SOLDER MASK DEFINED PAD (2.34) SOLDER MASK OPENING 8X (1.55) SEE DETAILS 1 8 8X (0.6) SYMM (1.3) TYP (2.34) SOLDER MASK OPENING (4.9) NOTE 9 6X (1.27) 5 4 (R0.05) TYP METAL COVERED BY SOLDER MASK SYMM ( 0.2) TYP VIA (1.3) TYP (5.4) LAND PATTERN EXAMPLE SCALE:10X 0.07 MIN ALL AROUND 0.07 MAX ALL AROUND SOLDER MASK OPENING METAL SOLDER MASK OPENING METAL UNDER SOLDER MASK SOLDER MASK DEFINED NON SOLDER MASK DEFINED SOLDER MASK DETAILS 4218825/A 05/2016 NOTES: (continued) 6. Publication IPC-7351 may have alternate designs. 7. Solder mask tolerances between and around signal pads can vary based on board fabrication site. 8. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature numbers SLMA002 (www.ti.com/lit/slma002) and SLMA004 (www.ti.com/lit/slma004). 9. Size of metal pad may vary due to creepage requirement. 10. Vias are optional depending on application, refer to device data sheet. If any vias are implemented, refer to their locations shown on this view. It is recommended that vias under paste be filled, plugged or tented. www.ti.com EXAMPLE STENCIL DESIGN DDA0008A PowerPAD TM SOIC - 1.7 mm max height PLASTIC SMALL OUTLINE (2.34) BASED ON 0.125 THICK STENCIL 8X (1.55) (R0.05) TYP 1 8 8X (0.6) (2.34) BASED ON 0.125 THICK STENCIL SYMM 6X (1.27) 5 4 METAL COVERED BY SOLDER MASK SYMM (5.4) SEE TABLE FOR DIFFERENT OPENINGS FOR OTHER STENCIL THICKNESSES SOLDER PASTE EXAMPLE EXPOSED PAD 100% PRINTED SOLDER COVERAGE BY AREA SCALE:10X STENCIL THICKNESS SOLDER STENCIL OPENING 0.1 0.125 0.150 0.175 2.62 X 2.62 2.34 X 2.34 (SHOWN) 2.14 X 2.14 1.98 X 1.98 4218825/A 05/2016 NOTES: (continued) 11. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate design recommendations. 12. Board assembly site may have different recommendations for stencil design. www.ti.com PACKAGE OUTLINE NGQ0008A WSON - 0.8 mm max height SCALE 4.000 PLASTIC SMALL OUTLINE - NO LEAD 3.1 2.9 B A PIN 1 INDEX AREA 3.1 2.9 C 0.8 0.7 SEATING PLANE 0.08 C 1.6 0.1 (0.1) TYP SYMM EXPOSED THERMAL PAD 0.05 0.00 4 5 SYMM 9 2X 1.5 2 0.1 8 1 6X 0.5 8X PIN 1 ID 8X 0.5 0.3 0.3 0.2 0.1 0.05 C A B C 4214922/A 03/2018 NOTES: 1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing per ASME Y14.5M. 2. This drawing is subject to change without notice. 3. The package thermal pad must be soldered to the printed circuit board for thermal and mechanical performance. www.ti.com EXAMPLE BOARD LAYOUT NGQ0008A WSON - 0.8 mm max height PLASTIC SMALL OUTLINE - NO LEAD (1.6) SYMM 8X (0.6) 1 8 (0.75) 8X (0.25) 9 SYMM (2) 6X (0.5) 5 4 (R0.05) TYP ( 0.2) VIA TYP (2.8) LAND PATTERN EXAMPLE EXPOSED METAL SHOWN SCALE:20X 0.07 MIN ALL AROUND 0.07 MAX ALL AROUND EXPOSED METAL EXPOSED METAL SOLDER MASK OPENING METAL METAL UNDER SOLDER MASK NON SOLDER MASK DEFINED (PREFERRED) SOLDER MASK OPENING SOLDER MASK DEFINED SOLDER MASK DETAILS 4214922/A 03/2018 NOTES: (continued) 4. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature number SLUA271 (www.ti.com/lit/slua271). 5. Vias are optional depending on application, refer to device data sheet. If any vias are implemented, refer to their locations shown on this view. It is recommended that vias under paste be filled, plugged or tented. www.ti.com EXAMPLE STENCIL DESIGN NGQ0008A WSON - 0.8 mm max height PLASTIC SMALL OUTLINE - NO LEAD 8X (0.6) SYMM 9 METAL TYP 8 1 8X (0.25) SYMM (1.79) 6X (0.5) 5 4 (R0.05) TYP (1.47) (2.8) SOLDER PASTE EXAMPLE BASED ON 0.1 mm THICK STENCIL EXPOSED PAD 9: 82% PRINTED SOLDER COVERAGE BY AREA UNDER PACKAGE SCALE:20X 4214922/A 03/2018 NOTES: (continued) 6. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. 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