Data Sheet Rev. 1.1 / August 2010 ZLED7000 40V LED Driver with Internal Switch ZLED7000 40V LED Driver with Internal Switch Brief Description Features Capable of up to 95% efficiency* Operates in continuous mode with a wide input range from 6 VDC to 40 VDC Integrated 40V power switch One pin on/off or brightness control via PWM or DC voltage control signal input Switching frequency: ≤ 1MHz Dimming rate: 1200:1 (typical) Output current accuracy: 5% (typical) Built-in thermal shutdown and open-circuit protection for LED Very few external components needed for operation Broad range of applications: outputs up to ≤750mA SOT89-5 package The ZLED7000, one of our ZLED Family of LED control ICs, is an inductive step-down converter that is optimal for driving a single LED or multiple LEDs (connected in series) from a voltage source greater than the voltage rating of the LED. The ZLED7000 operates in continuous mode. Capable of operating efficiently with voltage supplies ranging from 6 VDC to 40 VDC, it is ideal for low-voltage lighting applications. The ZLED7000 minimizes current consumption by remaining in a lowcurrent standby mode (output is off) until a voltage of ≥0.3V is applied to the ADJ pin. In operating mode, the ZLED7000 can source LEDs with an output current of ≤ 750mA (≤ 30 watts of output power) that is externally adjustable.* The ZLED7000’s integrated output switch and high-side current sensing circuit use an external resistor to adjust the average output current. Linearity is achieved via an external control signal at the ZLED7000’s ADJ pin, implemented either as a pulse-width modulation (PWM) waveform for a gated output current or a DC voltage for a continuous current. Application Examples Illuminated LED signs and other displays LED traffic and street lighting (low-voltage) Architectural LED lighting, including low-voltage applications for buildings Halogen replacement LEDs (low-voltage) LED backlighting General purpose exterior and interior LED lighting, including applications requiring low-voltage General purpose low-voltage industrial applications ZLED7000 Application Circuit 6 to 40 VDC RS VS D1 5 C1 ISENSE VIN 1μF n LED 4 ZLED7000 3 ADJ GND L1 LX 1 47μH 2 * See section 2.3 for details © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. ZLED7000 40V LED Driver with Internal Switch SOT89-5 Package Dimensions and Pin Assignments D D1 LX E1 E VIN GND Thermal Pad b1 ADJ L e ISENSE b e1 Dimension (mm) Symbol Dimension (mm) Symbol Min Max Min Max A 1.400 1.600 E 2.300 2.600 3.940 b 0.320 0.520 E1 b1 0.360 0.560 e 4.250 1.500 Typ c 0.350 0.440 e1 2.900 3.100 D 4.400 4.600 L 0.900 1.100 D1 1.400 1.800 Ordering Information Product Sales Code Description Package ZLED7000-ZI1R ZLED7000 – 40V LED Driver SOT89-5 (Tape & Reel) ZLED7000KIT-D1 ZLED7000 used in a MR16 Halogen replacement Demo Kit 12VAC/VDC, including 1 ZLED-PCB1 Kit ZLED-PCB1 Test PCB with one 3W white High Brightness (HB) LED, cascadable to one multiple LED string Printed Circuit Board (PCB) ZLED-PCB2 10 unpopulated test PCBs for modular LED string with footprints of 9 common HB LED types Printed Circuit Board (PCB) Sales and Further Information www.zmdi.com Zentrum Mikroelektronik Dresden AG (ZMD AG) Zentrum Mikroelektronik Dresden AG, Japan Office ZMD America, Inc. Grenzstrasse 28 01109 Dresden Germany 8413 Excelsior Drive Suite 200 Madison, WI 53717 USA Phone +49 (0)351.8822.7.533 Fax +49(0)351.8822.8.7533 Phone +1 (608) 829-1987 Fax +1 (631) 549-2882 [email protected] 2nd Floor, Shinbashi Tokyu Bldg. 4-21-3, Shinbashi, Minato-ku Tokyo, 105-0004 Japan Phone +81.3.6895.7410 Fax +81.3.6895.7301 ZMD Far East, Ltd. 3F, No. 51, Sec. 2, Keelung Road 11052 Taipei Taiwan Phone +886.2.2377.8189 Fax +886.2.2377.8199 DISCLAIMER: This information applies to a product under development. Its characteristics and specifications are subject to change without notice. Zentrum Mikroelektronik Dresden AG (ZMD AG) assumes no obligation regarding future manufacture unless otherwise agreed to in writing. The information furnished hereby is believed to be true and accurate. However, under no circumstances shall ZMD AG be liable to any customer, licensee, or any other third party for any special, indirect, incidental, or consequential damages of any kind or nature whatsoever arising out of or in any way related to the furnishing, performance, or use of this technical data. ZMD AG hereby expressly disclaims any liability of ZMD AG to any customer, licensee or any other third party, and any such customer, licensee and any other third party hereby waives any liability of ZMD AG for any damages in connection with or arising out of the furnishing, performance or use of this technical data, whether based on contract, warranty, tort (including negligence), strict liability, or otherwise. © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. ZLED7000 40V LED Driver with Internal Switch Contents 1 2 3 4 IC Characteristics .......................................................................................................................................................... 6 1.1 Absolute Maximum Ratings ................................................................................................................................... 6 1.2 Operating Conditions ............................................................................................................................................. 6 1.3 Electrical Parameters............................................................................................................................................. 6 1.4 Characteristic Operating Curves............................................................................................................................ 8 Circuit Description ....................................................................................................................................................... 10 2.1 Voltage Supply..................................................................................................................................................... 10 2.2 ZLED7000 Standby Mode.................................................................................................................................... 10 2.3 Output Current Control......................................................................................................................................... 10 2.3.1 Output Current and RS .................................................................................................................................. 10 2.3.2 PWM Control ................................................................................................................................................ 11 2.3.3 External DC Voltage Control of Output Current ............................................................................................ 11 2.3.4 Microcontroller LED Control.......................................................................................................................... 12 Application Circuit Design ........................................................................................................................................... 13 3.1 External Component – Inductor L1 ...................................................................................................................... 13 3.2 External Component – Capacitor C1 ................................................................................................................... 14 3.3 External Component – Diode D1 ......................................................................................................................... 14 3.4 Output Ripple....................................................................................................................................................... 15 Operating Conditions................................................................................................................................................... 16 4.1 Thermal Conditions.............................................................................................................................................. 16 4.2 Thermal Shut-Down Protection............................................................................................................................ 16 4.3 Open-Circuit Protection........................................................................................................................................ 16 5 ESD/Latch-Up-Protection ............................................................................................................................................ 16 6 Pin Configuration and Package................................................................................................................................... 17 7 Layout Requirements .................................................................................................................................................. 18 7.1 Layout Considerations for ADJ (Pin 3)................................................................................................................. 18 7.2 Layout Considerations for LX (Pin 1) ................................................................................................................... 18 7.3 Layout Considerations for VIN (Pin 5) and the External Decoupling Capacitor (C1)............................................. 18 7.4 Layout Considerations for GND (Pin 2)................................................................................................................ 18 7.5 Layout Considerations for High Voltage Traces................................................................................................... 18 7.6 Layout Considerations for the External Coil (L1) ................................................................................................. 18 7.7 Layout Considerations for the External Current Sense Resistor (RS) .................................................................. 18 8 Ordering Information ................................................................................................................................................... 18 9 Document Revision History ......................................................................................................................................... 19 Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 4 of 19 ZLED7000 40V LED Driver with Internal Switch List of Figures Figure 2.1 Directly Driving ADJ Input with a PWM Control Signal ................................................................................. 11 Figure 2.2 External DC Control Voltage at ADJ Pin....................................................................................................... 11 Figure 2.3 Driving ADJ Input from a Microcontroller ...................................................................................................... 12 Figure 3.1 Output Ripple Reduction .............................................................................................................................. 15 Figure 6.1 Pin Configuration and Package Drawing SOT89-5 ...................................................................................... 17 List of Tables Table 1.1 Absolute Maximum Ratings............................................................................................................................ 6 Table 1.2 Operating Conditions...................................................................................................................................... 6 Table 1.3 Electrical Parameters ..................................................................................................................................... 6 Table 4.1 Pin Description SOT89-5.............................................................................................................................. 17 Table 4.2 Package Dimensions SOT89-5 .................................................................................................................... 17 Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 5 of 19 ZLED7000 40V LED Driver with Internal Switch 1 1.1 IC Characteristics Absolute Maximum Ratings Table 1.1 Absolute Maximum Ratings No. PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNIT -0.3 50 V VIN > 5V VIN - 5 VIN + 0.3 V VIN < 5V 0 VIN + 0.3 V 1.1.1 Input voltage VIN 1.1.2 ISENSE voltage VISENSE 1.1.3 LX output voltage VLX -0.3 50 V 1.1.4 Adjust pin input voltage VADJ -0.3 6 V 1.1.5 Switch output current ILX SOT89-5 900 mA 1.1.6 Power dissipation Ptot SOT89-5 1200 mW 1.1.7 Storage temperature TST 150 °C 1.1.8 Junction temperature Tj MAX 150 °C MAX UNIT 1.2 -55 Operating Conditions Table 1.2 Operating Conditions No. PARAMETER SYMBOL CONDITIONS MIN TYP 1.2.1 Operating temperature TOP -40 +85 °C 1.2.2 Input voltage VIN 6 40 V 1.3 Electrical Parameters Production testing is at 25°C. At other temperatures within the specified operating range, functional operation of the chip and specified parameters are guaranteed by characterization, design, and process control. Test conditions are Tamb = 25°C; VIN = 12V except as noted. Table 1.3 Electrical Parameters No. PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNIT 40 60 80 μA 450 600 μA 95 101 mV 1.3.1 Quiescent supply current with output off IINQoff ADJ pin grounded 1.3.2 Quiescent supply current with output switching IINQon ADJ pin floating 1.3.3 Mean current sense threshold voltage 1.3.4 Sense threshold hysteresis 1.3.5 ISENSE pin input current ISENSE VSENSE = 0.1V 8 1.3.6 Internal reference voltage VREF Measured on ADJ pin with pin floating 1.2 1.3.7 External control voltage range on ADJ pin for DC brightness control VADJ Data Sheet August 12, 2010 91 VSENSE VSENSEHYS ±15 0.3 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. % 10 μA V 1.2 V 6 of 19 ZLED7000 40V LED Driver with Internal Switch No. PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNIT 1.3.8 DC voltage on ADJ pin to switch chip from active (ON) state to quiescent (OFF) state VADJoff VADJ falling 0.15 0.2 0.25 V 1.3.9 DC voltage on ADJ pin to switch chip from quiescent (OFF) state to active (ON) state VADJon VADJ rising 0.2 0.25 0.3 V 1.3.10 Resistance between ADJ pin and VREF RADJ 500 1.3.11 Continuous LX switch current ILXmean 0.65 1.3.12 LX switch leakage current ILX(leak) 1.3.13 LX Switch ON resistance RLX 1.3.14 Brightness control range at low frequency PWM signal 1.3.15 Brightness control range at high frequency PWM signal 1.3.16 Operating frequency 1.3.17 0.9 kΩ 0.75 A 1 μA 1.5 Ω DPWM(LF) PWM frequency =100Hz PWM amplitude=5V, VIN=15V, L=27μH, driving 1 LED 1200:1 DPWM(HF) PWM frequency =10kHz PWM amplitude=5V, VIN=15V, L=27μH, driving 1 LED 13:1 fLX ADJ pin floating L=100μH (0.82Ω) IOUT=350mA @ VLED=3.4V, driving 1 LED 154 kHz Minimum switch ON time TONmin LX switch ON 200 ns 1.3.18 Minimum switch OFF time TOFFmin LX switch OFF 200 ns 1.3.19 Recommended maximum operating frequency fLXmax 1.3.20 Recommended duty cycle range of output switch at fLXmax DLX 1.3.21 Internal comparator propagation delay TPD 50 ns 1.3.22 Thermal shutdown temperature TSD 140 °C 1.3.23 Thermal shutdown hysteresis TSD-HYS 20 °C Data Sheet August 12, 2010 1 0.2 MHz 0.8 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 7 of 19 ZLED7000 40V LED Driver with Internal Switch 1.4 Characteristic Operating Curves The curves are valid for the typical application circuit and Tamb = 25°C unless otherwise noted. Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 8 of 19 ZLED7000 40V LED Driver with Internal Switch Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 9 of 19 ZLED7000 40V LED Driver with Internal Switch 2 Circuit Description The ZLED7000 is an inductive step-down converter for driving LEDs. It operates in continuous mode, enabling proper LED current control. The ZLED7000 supports linear or PWM control of the LED current. Only a few external components are needed for typical applications. 2.1 Voltage Supply The ZLED7000 has an internal regulator that disables the LX output until the voltage supply rises above a start-up threshold voltage set internally as needed to ensure that the power MOSFET on-resistance is low enough for proper operation. When the supply voltage exceeds the threshold, the ZLED7000 begins normal operation. Important: The ZLED7000 must be operated within the operating voltage range specified in Table 1.2 to avoid conditions that could result in thermal damage to the ZLED7000. Operating with the supply voltage below the minimum can result in a high switch duty cycle and excessive ZLED7000 power dissipation, risking overtemperature conditions (also see section 4.1 regarding thermal restrictions) that could result in activation of the ZLED7000’s thermal shut-down circuitry. With multiple LEDs, the forward drop is typically adequate to prevent the chip from switching below the minimum voltage supply specification (6V), so there is less risk of thermal shut-down. 2.2 ZLED7000 Standby Mode Whenever the ADJ pin voltage falls below 0.2V, the ZLED7000 turns the output off and the supply current drops to approximately 60μA. This standby mode minimizes current consumption. 2.3 Output Current Control The LED control current output on the LX pin is determined by the value of external components and the control voltage input at the ADJ pin. Selection of the external component RS is discussed below, and other external components are discussed in section 2.3.4. The subsequent sections describe the two options for control voltage input at the ADJ pin: a pulse width modulation (PWM) control signal or a DC control voltage. The ADJ pin has an input impedance † of 500kΩ ±25%. 2.3.1 Output Current and RS The current sense threshold voltage and the value of the external current sense resistor (RS) between VIN and ISENSE set the output current through the LEDs (IOUT). Equation (1) below shows this basic relationship. Unless the ADJ pin is driven from an external voltage (see section 2.3.3), the minimum value for RS is 0.13 Ω to prevent exceeding the maximum switch current (see Table 1.1). I OUT 95mV RS (1) Where IOUT = Nominal average output current through the LED(s) RS ≥0.13Ω † At room temperature. Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 10 of 19 ZLED7000 40V LED Driver with Internal Switch 2.3.2 PWM Control The output current on LX can be set to a value below the nominal average value determined by resistor RS by using an external PWM signal as the control signal applied to the ADJ pin. This control signal must be capable of driving the ZLED7000’s internal 500kΩ pull-up resistor. See Figure 2.1 for an illustration. The minimum signal voltage range is 0V to 1.8V; the maximum voltage range is 0V to 5V. See Table 1.3 for the specifications for the signal’s duty cycle DPWM. Any negative spikes on the control signal could interfere with current control or proper operation of the ZLED7000. Figure 2.1 Directly Driving ADJ Input with a PWM Control Signal ZLED 7000 1.8V to 5V 0V ADJ PWM 2.3.3 GND External DC Voltage Control of Output Current The output current on LX can be set to a value below the nominal average value determined by resistor RS by using an external DC voltage VADJ (0.3 V ≤ VADJ ≤ 1.2V) to drive the voltage at the ADJ pin. This allows adjusting the output current from 25% to 100% of IOUTnom. See Figure 2.2 for an illustration. The output current can be calculated using equation (2). If VADJ matches or exceeds VREF (1.2V), the brightness setting is clamped at its maximum (100%). Figure 2.2 External DC Control Voltage at ADJ Pin ZLED7000 ADJ GND DC I OUT _ DC 0.079 V ADJ RS (2) Where IOUT_DC = Nominal average output current through the LED(s) with a DC control voltage VADJ = External DC control voltage: 0.3 V ≤ VADJ ≤ 1.2V RS ≥0.13Ω Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 11 of 19 ZLED7000 40V LED Driver with Internal Switch 2.3.4 Microcontroller LED Control A microcontroller’s open-drain output can control current to the LED(s) by outputting a PWM control signal to the ADJ input of the ZLED7000. See Figure 2.1 for an example circuit. Figure 2.3 Driving ADJ Input from a Microcontroller MC Data Sheet August 12, 2010 ZLED7000 10k ADJ GND © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 12 of 19 ZLED7000 40V LED Driver with Internal Switch 3 Application Circuit Design The following sections cover selection of the external components shown in the typical application illustrated on page 2. 3.1 External Component – Inductor L1 Select the inductor value for L1 as needed to ensure that switch on/off times are optimized across the load current and supply voltage ranges. Select a coil that has a continuous current rating above the required average output current to the LEDs and a saturation current exceeding the peak output current. Recommendation: Use inductors in the range of 15μH to 220μH with saturation current greater than 1A for 700mA output current or saturation current greater than 500mA for 350mA output current. For higher supply voltages with low output current, select higher values of inductance, which result in a smaller change in output current across the supply voltage range (refer to the graphs in section 1.4). See section 7.6 for layout restrictions. Equations (3) and (4) illustrate calculating the timing for LX switching for the example application circuit shown on page 2. As given in Table 1.3, the minimum period for TON is 200ns; the minimum period for TOFF is also 200ns. LX Switch OFF Time TOFF in s TOFF VLED L I VD I AVG RS rL Where (3) LX Switch ON Time TON in s TON V IN VLED L I I AVG RS rL RLX (4) L Coil inductance in H ∆I Coil peak-peak ripple current in A * VLED Total LED forward voltage in V VD Diode forward voltage at the required load current in V IAVG Required average LED current in A RS External current sense resistance in Ω rL Coil resistance in Ω VIN Supply voltage in V RLX Switch resistance in Ω * With the ZLED7000, the current ripple ∆I is internally set to an appropriate value of 0.3 * IAVG. The inductance value has an equivalent effect on Ton and Toff and therefore affects the switching frequency. For the same reason, the inductance has no influence on the duty cycle for which the relation of the summed LED forward voltages n VF to the input voltage VIN is a reasonable approximation. Because the input voltage is a factor in the ON time, variations in the input voltage affect the switching frequency and duty cycle. Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 13 of 19 ZLED7000 40V LED Driver with Internal Switch The following calculation example yields an operating frequency of 122kHz and a duty cycle of 0.33: Input data: VIN=12V, L=220μH, rL=0.48Ω, VLED=3.4V, IAVG =333mA and VD =0.36V TOFF 220 H 0.3 0.333 A 5.47 s 3.4V 0.36V 0.333 A 0.48 0.3 (5) TON 220 H 0.3 0.333 A 2.73 s 12V 3.4V 0.333 A 0.3 0.48 0.9 (6) And 3.2 External Component – Capacitor C1 To improve system efficiency, use a low-equivalent-series-resistance (ESR) capacitor for input decoupling because this capacitor must pass the input current AC component. The capacitor value is defined by the target maximum ripple of the supply voltage; the value is given by equation (7). C MIN I F TON VMAX (7) Where IF ΔVMAX TON Value of output current Maximum ripple of power supply Maximum ON time of MOSFET In the case of an AC supply with a rectifier, the capacitor value must be chosen high enough to make sure that the DC voltage does not drop below the maximum forward voltage of the LED string plus some margin for the voltage drops across the coil resistance, shunt resistor, and ON resistance of the switching transistor. Recommendation: Use capacitors with X5R, X7R, or better dielectric for maximum stability over temperature and voltage. Do not use Y5V capacitors for decoupling in this application. For higher capacitance values, aluminum electrolytic caps with high switching capability should be used. In this case, improved performance can be reached by an additional X7R/X5R bypass capacitor of at least 100nF. 3.3 External Component – Diode D1 For the rectifier D1, select a high-speed, low-capacitance Schottky diode with low reverse leakage at the maximum operating voltage and temperature to ensure maximum efficiency and performance. Important: Choose diodes with a continuous current rating higher than the maximum output load current and a peak current rating above the peak coil current. When operating above 85°C, the reverse leakage of the diode must be addressed because it can cause excessive power dissipation in the ZLED7000. Note: Silicon diodes have a greater forward voltage and overshoot caused by reverse recovery time, which can increase the peak voltage on the LX output. Ensure that the total voltage appearing on the LX pin, including supply ripple, is within the specified range (see Table 1.1). Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 14 of 19 ZLED7000 40V LED Driver with Internal Switch 3.4 Output Ripple Shunt a capacitor CLED across the LED(s) as shown in Figure 3.1 to minimize the peak-to-peak ripple current in the LED if necessary. Figure 3.1 Output Ripple Reduction RS VS D1 C1 VIN n LED ISENSE ZLED7000 ADJ GND CLED L1 LX Low ESR capacitors should be used because the efficiency of CLED largely depends on its ESR and the dynamic resistance of the LED(s). For an increased number of LEDs, using the same capacitor will be more effective. Lower ripple can be achieved with higher capacitor values, but this will increase start-up delay by reducing the slope of the LED voltage. The capacitor will not affect operating frequency or efficiency. For a simulation or bench optimization, CLED values of a few μF are an applicable starting point for the given configuration. Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 15 of 19 ZLED7000 40V LED Driver with Internal Switch 4 4.1 Operating Conditions Thermal Conditions Refer to Table 1.1 for maximum package power dissipation specifications for the ZLED7000’s SOT89-5 package. Exceeding these specifications due to operating the chip at high ambient temperatures (see Table 1.2 for maximum operating temperature range) or driving over the maximum load current (see Table 1.1) can damage the ZLED7000. The ZLED7000 can be used for LED current applications up to750mA when properly mounted to a high wattage land pattern. Conditions such as operating below the minimum supply voltage or inefficiency of the circuit due to improper coil selection or excessive parasitic capacitance on the output can cause excessive chip power dissipation. 4.2 Thermal Shut-Down Protection The ZLED7000 includes an on-board temperature sensing circuit which stops the output if the junction exceeds approximately 160°C. 4.3 Open-Circuit Protection The ZLED7000 is inherently protected if there is an open-circuit in the connection to the LEDs because in this case, the coil is isolated from the LX pin. This prevents any back EMF from damaging the internal switch due to forcing the drain above its breakdown voltage. 5 ESD/Latch-Up-Protection All pins have an ESD protection of >± 2000V according to the Human Body Model (HBM) except for pin 1, which has a protection level of >± 1000V. The ESD test follows the Human Body Model with 1.5 kΩ/100 pF based on MIL 883-G, Method 3015.7 Latch-up protection of >± 100mA has been proven based on JEDEC No. 78A Feb. 2006, temperature class 1. Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 16 of 19 ZLED7000 40V LED Driver with Internal Switch 6 Pin Configuration and Package Figure 6.1 Pin Configuration and Package Drawing SOT89-5 D A D1 E1 E LX VIN GND Thermal Pad ADJ ISENSE b1 L e b c e1 Table 4.1 Pin Description SOT89-5 Pin Name No. LX 1 Power switch drain GND 2 Ground (0V)—see section 7.4 for layout considerations ADJ 3 Output current control pin—see section 2.3 for details ISENSE 4 Nominal average output current is set by the value of a resistor RS connected from ISENSE to VIN – see section 2.3.1 for details VIN 5 Supply voltage (6V to 40V)—see section 7.3 for layout considerations Table 4.2 Symbol Description Package Dimensions SOT89-5 Dimension (mm) Min Max A 1.400 1.600 b 0.320 b1 Symbol Dimension (mm) Min Max E 2.300 2.600 0.520 E1 3.940 4.250 0.360 0.560 e c 0.350 0.440 e1 2.900 3.100 D 4.400 4.600 L 0.900 1.100 D1 1.400 1.800 1.500 Typ The SOT89-5 package has a thermal resistance (junction to ambient) of RθJA = 45 K/W. Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 17 of 19 ZLED7000 40V LED Driver with Internal Switch 7 7.1 Layout Requirements Layout Considerations for ADJ (Pin 3) For applications in which the ADJ pin is unconnected, minimize the length of circuit board traces connected to ADJ to reduce noise coupling through this high impedance input. 7.2 Layout Considerations for LX (Pin 1) Minimize the length of circuit board traces connected to the LX pin because it is a fast switching output. 7.3 Layout Considerations for VIN (Pin 5) and the External Decoupling Capacitor (C1) The C1 input decoupling capacitor must be placed as close as possible to the VIN pin to minimize power supply noise, which can reduce efficiency. See section 3.2 regarding capacitor selection. 7.4 Layout Considerations for GND (Pin 2) The ZLED7000 GND (ground) pin must be soldered directly to the circuit board’s ground plane to minimize ground bounce due to fast switching of the LX pin. 7.5 Layout Considerations for High Voltage Traces Avoid laying out any high voltage traces near the ADJ pin to minimize the risk of leakage in cases of board contamination, which could raise the ADJ pin voltage resulting in unintentional output current. Leakage current can be minimized by laying out a ground ring around the ADJ pin. 7.6 Layout Considerations for the External Coil (L1) The L1 coil must be placed as close as possible to the chip to minimize parasitic resistance and inductance, which can reduce efficiency. The connection between the coil and the LX pin must be low resistance. 7.7 Layout Considerations for the External Current Sense Resistor (RS) Any trace resistance in series with RS must be taken into consideration when selecting the value for RS. 8 Ordering Information Product Sales Code Description Package ZLED7000-ZI1R ZLED7000 – 40V LED Driver SOT89-5 (Tape & Reel) ZLED7000KIT-D1 ZLED7000 used in a MR16 Halogen replacement Demo Kit 12VAC/VDC, including 1 ZLED-PCB1 Kit ZLED-PCB1 Test PCB with one 3W white High Brightness (HB) LED, cascadable to one multiple LED string Printed Circuit Board (PCB) ZLED-PCB2 10 unpopulated test PCBs for modular LED string with footprints of 9 common HB LED types Printed Circuit Board (PCB) Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 18 of 19 ZLED7000 40V LED Driver with Internal Switch 9 Document Revision History Revision Date Description 1.0 June 10, 2010 1.1 August 12, 2010 Production release version Revision to equation (5) for Toff. Update for contact information. Sales and Further Information www.zmdi.com Zentrum Mikroelektronik Dresden AG (ZMD AG) Zentrum Mikroelektronik Dresden AG, Japan Office ZMD America, Inc. Grenzstrasse 28 01109 Dresden Germany 8413 Excelsior Drive Suite 200 Madison, WI 53717 USA Phone +49 (0)351.8822.7.533 Fax +49(0)351.8822.8.7533 Phone +1 (608) 829-1987 Fax +1 (631) 549-2882 [email protected] 2nd Floor, Shinbashi Tokyu Bldg. 4-21-3, Shinbashi, Minato-ku Tokyo, 105-0004 Japan Phone +81.3.6895.7410 Fax +81.3.6895.7301 ZMD Far East, Ltd. 3F, No. 51, Sec. 2, Keelung Road 11052 Taipei Taiwan Phone +886.2.2377.8189 Fax +886.2.2377.8199 DISCLAIMER: This information applies to a product under development. Its characteristics and specifications are subject to change without notice. Zentrum Mikroelektronik Dresden AG (ZMD AG) assumes no obligation regarding future manufacture unless otherwise agreed to in writing. The information furnished hereby is believed to be true and accurate. However, under no circumstances shall ZMD AG be liable to any customer, licensee, or any other third party for any special, indirect, incidental, or consequential damages of any kind or nature whatsoever arising out of or in any way related to the furnishing, performance, or use of this technical data. ZMD AG hereby expressly disclaims any liability of ZMD AG to any customer, licensee or any other third party, and any such customer, licensee and any other third party hereby waives any liability of ZMD AG for any damages in connection with or arising out of the furnishing, performance or use of this technical data, whether based on contract, warranty, tort (including negligence), strict liability, or otherwise. Data Sheet August 12, 2010 © 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.1 All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice. 19 of 19