ZXLD1362QET5TA

ZXLD1362_14 DIODES | Alldatasheet

Document overview

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• PDF pages: 25

Technical content

Features

• Simple low parts count
• Single pin on/off and brightness control using DC voltage or PWM
• High efficiency (up to 95%)
• Wide input voltage range: 6V to 60V
• Up to 1MHz switching frequency
• Qualified to AEC-Q100 Grade 1
• Automotive Grade version available (ZXLD1362Q)
• Typical 2% output current accuracy
• Thermally enhanced TSOT25: θJA 82°C/W
• Available in Green Molding
• Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
• Halogen and Antimony Free. “Green” Device (Note 3) Pin Assignments ISENSE VIN ADJ GND LX TSOT25 (Top View) Notes: 1. No purposely added lead. Fully EU Directiv e 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See http://www.diodes.com/quality/lead_free.html for more in formation about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free. 3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. Typical Application Circuit SETVIN LX GND ADJ ZXLD1362 RS 0.1Ω 68µH 4.7µF GND VIN 24V 100nF

Document number: DS33472 Rev. 6 - 2 2 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Pin Description Name Pin No. Function LX 1 Drain of NDMOS switch GND 2 Ground (0V) ADJ 3 Multi-function On/Off and brightness control pin: Leave floating for normal operation.(VADJ = VREF = 1.25V giving nominal average output current IOUTnom = 0.1/RS) Drive to voltage below 0.2V to turn off output current Drive with DC voltage (0.3V < VADJ < 2.5V) to adjust output current from 25% to 200% of IOUTnom Connect a capacitor from this pin to ground to increase soft-start time. Soft-start time increases approximately 200µs/nF. ISENSE 4 Connect resistor RS from this pin to VIN to define nominal average output current IOUTnom = 0.1/RS (Note: RSMIN = 0.1Ω with ADJ pin open circuit) VIN 5 Input voltage (6V to 60V). Decouple to ground with 4. 7µF of higher X7R ceramic capacitor close to device. Block Diagram Voltage regulator Low voltage detector LXISENSEVIN RS 54 1 0.2V 1.35V 20k 50k 1.25V ADJ GND 4.7µF VIN MNGND GND Figure 1 Block Diagram

Document number: DS33472 Rev. 6 - 2 3 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Absolute Maximum Ratings (Note 4) (@TA = +25°C, unless otherwise specified.) Symbol Parameter Rating Unit VIN Input Voltage -0.3 to +65 V VSENSE I SENSE Voltage (Note 5) +0.3 to -5 V VLX LX Output Voltage -0.3 to +65 V VADJ Adjust Pin Input Voltage -0.3 to +6 V ILX Switch Output Current 1.25 A PTOT Power Dissipation (Refer to Package thermal de-rating curve on page 16) 1 W TST Storage Temperature -55 to +150 °C TJ MAX Junction Temperature 150 °C Note: 4 All voltages unless otherwise stated are measured with respect to GND. 5. V SENSE is measured with respect to VIN. Caution: Stresses greater than the 'Absolute Maximum Ratings' sp ecified above, may cause permanent damage to the device. These are stress ratings only; functional operation of the devic e at conditions between maximum recommended operating conditions and absolute maximum ratings is not implied. Device reliability may be affected by exposure to absolute maximum rating conditions for extended periods of time. ESD Susceptibility Rating Unit Human Body Model 500 V Machine Model 75 V Caution: Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD precautions should be taken when handling and transporting these devices. The human body model is a 100pF capacitor discharge through a 1.5k Ω resistor pin. The machine model is a 200pF capacitor discharged directly into each pin. Thermal Resistance Symbol Parameter Rating Unit ΘJA Junction to Ambient 82 °C/W ΨJB Junction to Board 33 °C/W Recommended Operating Conditions (@TA = +25°C, unless otherwise specified.) Symbol Parameter Min Max Units VIN Input Voltage Range (Note 6) 6 60 V ILX Maximum recommended continuous/RMS switch current 1 A VADJ External control voltage range on ADJ pin for DC brightness control (Note 7) 0.3 2.5 V VADJoff DC voltage on ADJ pin to ensure devices is off 0.25 V tONMIN Minimum switch on-time 800 ns fLXmax Recommended maximum operating frequency (Note 8) 625 kHz DLX Duty cycle range 0.01 0.99 TA Ambient operating temperature range -40 +125 °C Notes: 6. V IN > 16V to fully enhance output transistor. Otherwise out current must be derated - see graphs. Operation at low supply may cause excessive heating due to increased on-resistance. Tested at 7V guaranteed for 6V by design. 7. 100% brightness corresponds to V ADJ = VADJ(nom) = VREF. Driving the ADJ pin above VREF will increase the VSENSE threshold and output current proportionally. 8. ZXLD1362 will operate at higher frequencies but accuracy will be affected due to propagation delays.

Document number: DS33472 Rev. 6 - 2 4 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Electrical Characteristics (@ VIN = 24V, TA = +25°C, unless otherwise specified.) Symbol Parameter Condition Min Typ Max Unit VSU Internal regulator start-up threshold 4.85 V VSD Internal regulator shutdown threshold 4.75 V IINQoff Quiescent supply current with output off ADJ pin grounded 65 90 µA IINQon Quiescent supply current with output switching (Note 9) ADJ pin floating, L = 68µH, 3 LEDs, f = 260kHz 1.8 mA VSENSE Mean current sense threshold voltage (Defines LED current setting accuracy) Measured on ISENSE pin with respect to VIN VADJ = 1.25V 95 100 105 mV VSENSEHYS Sense threshold hysteresis ±10 % ISENSE I SENSE pin input current V SENSE = VIN -0.1 4 10 µA VREF Internal reference voltage Measured on ADJ pin with pin floating 1.25 V ΔVREF/ΔT Temperature coefficient of V REF 50 ppm/°C VADJ External control voltage range on ADJ pin for DC brightness control (Note 7) 0.3 2.5 V VADJoff DC voltage on ADJ pin to switch device from active (on) state to quiescent (off) state VADJ falling 0.15 0.2 0.27 V VADJon DC voltage on ADJ pin to switch device from quiescent (off) state to active (on) state VADJ rising 0.2 0.25 0.3 V RADJ Resistance between ADJ pin and V REF 0 < VADJ < VREF VADJ > VREF +100mV 10.4 14.2 18 kΩ ILXmean Continuous LX switch current 1 A RLX LX switch ‘On’ resistance @ ILX = 1A 0.5 1.0 Ω ILX(leak) LX switch leakage current 5 µA DPWM(LF) Duty cycle range of PWM signal applied to ADJ pin during low frequency PWM dimming mode PWM frequency <300Hz PWM amplitude = VREF Measured on ADJ pin 0.001 1 Brightness control range 1000:1 DCADJ DC Brightness control range Note 10 5:1 tSS Soft start time Time taken for output current to reach 90% of final value after voltage on ADJ pin has risen above 0.3V. Requires external capacitor 22nF. See graphs for more details 2 ms fLX Operating frequency (See graphs for more details) ADJ pin floating L = 68µH (0.1V) IOUT = 1A @ VLED = 3.6V Driving 3 LEDs 300 kHz tONmin Minimum switch ‘ON’ time LX switch ‘ON’ 130 ns tOFFmin Minimum switch ‘OFF’ time LX switch ‘OFF’ 70 ns Notes: 9. Static current of device is approximately 700µA, see Graph, Page 16.

Document number: DS33472 Rev. 6 - 2 5 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Device Description The device, in conjunction with the coil (L1) and current sense resistor (RS), forms a self-oscillating continuous-mode buck converter. Device operation (refer to Figure 1 - Block diagram and Figure 2 Operating waveforms) Figure 2 Theoretical Operating Waveforms Operation can be best understood by assuming that the ADJ pin of the device is unconnected and the voltage on this pin (V ADJ) appears directly at the (+) input of the comparator. When input voltage V IN is first applied, the initial current in L1 and R S is zero and there is no output from the current sense circuit. Under this condition, the (-) input to the comparator is at ground and its output is high. This turns MN on and switches the LX pin low, causing current to flow from VIN to ground, via R S, L1 and the LED(s). The current rises at a rate determined by V IN and L1 to produce a voltage ramp (V SENSE) across RS. The supply referred voltage V SENSE is forced across internal resistor R1 by the curr ent sense circuit and produces a proportional current in internal resistors R2 and R3. This produces a ground referred ri sing voltage at the (-) input of the comparator. When this reac hes the threshold voltage (VADJ), the comparator output switches low and MN turns off. The co mparator output also drives another NMOS switch, which bypasses internal resistor R3 to provide a controlled amount of hysteresis. The hysteresis is set by R3 to be nominally 10% of VADJ. When MN is off, the current in L1 continues to flow via D1 and the LED(s) back to V IN. The current decays at a rate determined by the LED(s) and diode forward voltages to produce a falling voltage at the input of the comparator. When this voltage returns to V ADJ, the comparator output switches high again. This cycle of events repeats, with the comparator input ramping between limits of VADJ ± 10%.

Document number: DS33472 Rev. 6 - 2 6 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Device Description (cont.) Switching Thresholds With VADJ = VREF, the ratios of R1, R2 and R3 define an average V SENSE switching threshold of 100mV (measured on the ISENSE pin with respect to VIN). The average output current IOUTnom is then defined by this voltage and RS according to: IOUTnom = 100mV/RS Nominal ripple current is ±10mV/RS Adjusting output current The device contains a low pass filter between the ADJ pin and the threshold comparator and an internal current limiting resisto r (50kΩ nom) between ADJ and the internal reference voltage. This allows the ADJ pin to be overdriven with either DC or pulse signals to change the VSENSE switching threshold and adjust the output current. Details of the different modes of adjusting output current are given in the applications section. Output Shutdown The output of the low pass filter drives the shutdown circuit. When the input voltage to this ci rcuit falls below the threshold (0.2V nom.), the internal regulator and the output switch are turned off. The volt age reference remains powered during shutdown to provide the b ias current for the shutdown circuit. Quiescent supply current during shutdown is nominally 60μA and switch leakage is below 5μA. Actual Operating Waveforms VIN = 15V, RS = 0.1V, L = 100µH Normal operation. Output Current (Ch1) and LX Voltage (Ch2) VIN = 30V, RS = 0.1V, L = 100µH Normal Operation. Output Current (Ch1) and LX Voltage (Ch2) VIN = 60V, RS = 0.1V, L = 100µH Normal Operation. Output Current (Ch1) and LX Voltage (Ch2)

Document number: DS33472 Rev. 6 - 2 7 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Typical Characteristics 0 7040 50 6010 20 30 ZXLD1362 Output Current L = 68µH Supply Voltage (V)

15 LED13 LED11 LE D9 LED7 LED5 LED3 LED1 LED

Output Current (mA) 0 7040 50 6010 20 30 ZXLD1362 Output Current L = 68µH Supply Voltage (V) 10%Output Current Deviation -10% -8% -6% -4% -2%

15 LED13 LED11 LED9 LED7 LED5 LED3 LED1 LED

100%Ef ficiency (%) 50% 60% 70% 90% 80% 0 7040 50 6010 20 30 Supply Voltage (V) L = 68µH

Document number: DS33472 Rev. 6 - 2 8 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Typical Characteristics (cont.) ZXLD1362 Switching Frequenc y L = 68µH 500 Switching Frequency (kHz) 100 200 400 300 Supply Voltage (V) Supply Voltage (V) ZXLD1362 Duty Cycle L = 68µH 100 Duty Cycle (%)

Document number: DS33472 Rev. 6 - 2 9 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Typical Characteristics (cont.) 1000 11 00 1010 1090 1020 1080 1030 1070 1040 1060 1050 Output Current (mA) Supply Voltage (V) ZXLD1362 Output Current L = 100µH ZXLD1362 Output Current L = 100µH Supply Voltage (V) -10% 10% -8% -6% -4% -2% Output Current Deviation Supply Voltage (V) ZXLD1362 Efficienc y L = 100µH 100%Ef ficiency (%) 50% 60% 70% 90% 80%

Document number: DS33472 Rev. 6 - 2 10 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Typical Characteristics (cont.) ZXLD1362 Switching Frequency L = 100µH 500 Switching Frequency (kHz) 100 200 400 300 Supply Voltage (V) ZXLD1362 Switching Frequenc y L = 100µH Supply Voltage (V) 100 Duty Cycle (%)

Document number: DS33472 Rev. 6 - 2 11 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Typical Characteristics (cont.) ZXLD1362 Output Current L = 150µH 1000 11 00 1010 1090 1020 1080 1030 1070 1040 1060 1050 Output Current (mA) Supply Voltage (V) Supply Voltage (V) ZXLD1362 Output Current L = 150µH -10% 10% -8% -6% -4% -2% Output Current Deviation Supply Voltage (V) ZXLD1362 Efficienc y L = 150µH 100%Ef ficiency (%) 50% 60% 70% 90% 80%

Document number: DS33472 Rev. 6 - 2 12 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Typical Characteristics (cont.) ZXLD1362 Switching Frequenc y L = 150µH Supply Voltage (V) 500 Switching Frequency (kHz) 100 200 400 300 ZXLD1362 Duty Cycle L = 150µH Supply Voltage (V) 100 Duty Cycle (%)

Document number: DS33472 Rev. 6 - 2 13 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Typical Characteristics (cont.) ZXLD1362 Output Current L = 220µH Supply Voltage (V) 1000 11 00 1010 1090 1020 1080 1030 1070 1040 1060 1050 Output Current (mA) ZXLD1362 Output Current L = 220µH -10% 10% -8% -6% -4% -2% Output Current Deviation Supply Voltage (V) Supply Voltage (V) 100%Ef ficiency (%) 50% 60% 70% 90% 80% ZXLD1362 Efficienc y L = 220µH

Document number: DS33472 Rev. 6 - 2 14 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Typical Characteristics (cont.) ZXLD1362 Switching Frequency L = 2200µH Supply Voltage (V) 500 Switching Frequency (kHz) 100 200 400 300 ZXLD1362 Duty Cycle L = 2200µH Supply Voltage (V) 100 Duty Cycle (%)

Document number: DS33472 Rev. 6 - 2 15 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Typical Characteristics (cont.) LED Current vs Vadj 200 400 600 800 1000 1200 0123 ADJ Pin Voltage (V) LED Current (mA) R=100mΩ R=150mΩ R=330mΩ Vref 1.238 1.2385 1.239 1.2395 1.24 1.2405 1.241 1.2415 1.242 1.2425 1.243 0 1 02 03 04 05 06 07 0 ADJ pin voltage (V) Supply current 100 200 300 400 500 600 700 800 0 1 02 03 04 05 06 07 0 Supply voltage (V) Supply voltage (V) Supply voltage (V) Supply current (mA) Shutdow n current 0 1 02 03 0 4 05 06 07 0 Shutdown current (mA)

Document number: DS33472 Rev. 6 - 2 16 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Typical Characteristics (cont.) Lx on-resistance vs die temperature 0.2 0.4 0.6 0.8 1.2 1.4 1.6 -50 0 50 100 150 200 Die Temperature (C) On-resistance (Oh ms) 12V 20V 30V Lx on-resistance vs supply voltage 0.2 0.4 0.6 0.8 1.2 1.4 1.6 0 5 10 15 20 25 30 35 Supply Voltage (V) On-resistance (Ohms) -40C 20C 150C Vadj vs Temperature 1.244 1.246 1.248 1.25 1.252 1.254 1.256 1.258 1.26 1.262 -50 0 50 100 150 200 Temperature (C) Vadj (V) 12V 20V 30V

Document number: DS33472 Rev. 6 - 2 17 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362

Application Information

Setting Nominal Average Output Current with External Resistor RS The nominal average output current in the LED(s) is determined by the value of the external current sense resistor (R S) connected between V IN and ISENSE and is given by: IOUTnom = 0.1/RS [for RS > 0.1Ω] The table below gives values of nominal average output current for several preferred values of current setting resistor (R S) in the typical application circuit shown on page 1: RS (Ω) Nominal Average Output Current (mA) 0.1 1000 0.13 760 0.15 667 The above values assume that the ADJ pin is floating and at a nominal voltage of V REF (= 1.25V). Note that R S = 0.1Ω is the minimum allowed value of sense resistor under these conditions to maintain switch current below the specified maximum value. It is possible to use different values of RS if the ADJ pin is driven from an external voltage. (See next section). Output Current Adjustment by External DC Control Voltage The ADJ pin can be driven by an external dc voltage (V ADJ), as shown, to adjust the output current to a value above or below the nominal average value defined by RS. GND ZXLD1362ADJ GND DC The nominal average output current in this case is given by: IOUTdc = (VADJ /1.25) x (100mV/RS) [for 0.3< VADJ <2.5V] Note that 100% brightness setting corresponds to V ADJ = V REF. When driving the ADJ pin above 1.25V, R S must be increased in proportion to prevent IOUTdc exceeding 1A maximum. The input impedance of the ADJ pin is 50kΩ ±25% for voltages below VREF and 14.2kΩ ±25% for voltages above VREF +100mV. Output Current Adjustment by PWM Control Directly driving ADJ input A Pulse Width Modulated (PWM) signal with duty cycle D PWM can be applied to the ADJ pin, as shown below, to adjust the output current to a value above or below the nominal average value set by resistor RS: PWM GND VADJ GND ZXLD1362ADJ

Document number: DS33472 Rev. 6 - 2 18 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Application Information (cont.) Driving the ADJ Input via Open Collector Transistor The recommended method of driving the ADJ pin and controlling the am plitude of the PWM waveform is to use a small NPN switching transistor as shown below: PWM GND ZXLD1362ADJ GND This scheme uses the 50k resistor between the ADJ pin and the internal voltage reference as a pull-up resistor for the external transistor. Driving the ADJ Input from a Microcontroller Another possibility is to drive the device from the open drain output of a microcontroller. The diagram below shows one method of doing this: GND ZXLD1362ADJ MCU 3.3k If the NMOS transistor within the microcontroller has high Gate / Drain capacitance, this arrangement can inject a negative spi ke into ADJ input of the 1362 and cause erratic operation but th e addition of a Schottky clamp diode (cathode to ADJ) to ground and inclusion of a series resistor (3.3k) will prevent this. See the section on PWM dimming for more details of the various modes of control using high frequency and low frequency PWM signals. Shutdown Mode Taking the ADJ pin to a voltage below 0.2V for more than approximately 100µs will turn off the output and supply current to a l ow standby level of 20µA nominal. Note that the ADJ pin is not a logic input. Taking the ADJ pin to a voltage above V REF will increase output current above the 100% nominal average value. (See page 18 graphs for details). Soft-Start An external capacitor from the ADJ pin to ground will provide a soft-start delay, by increasing the time taken for the voltage on this pin to rise to the turn-on threshold and by slowing down the rate of rise of the control voltage at the input of the comparator. Adding capaci tance increases this delay by approximately 200µs/nF. The graph below shows the variation of soft-start time for different values of capacitor. 40 6002 0 8 0 1 00 1 20 CAPACITANCE (nF) Soft Start Time vs. Capacitance from ADJ Pin to Ground SOFT START TIME (ms) VIN = 24V, RS = 0.1Ω, L = 68µH, 22nF on ADJ Soft-start operation. Output current (Ch2) and LX voltage (Ch1)

Document number: DS33472 Rev. 6 - 2 19 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Application Information (cont.) VIN Capacitor Selection A low ESR capacitor should be used for input decoupling, as the ESR of this capacitor appears in series with the supply source impedance and lowers overall efficiency. This capacitor has to supply the relatively high peak current to the coil and smooth the current ripple on the input supply. To avoid transients into the IC, the size of the input capacitor will depend on the VIN voltage: VIN = 6 to 40V CIN = 2.2μF VIN = 40 to 50V CIN = 4.7μF VIN = 50 to 60V CIN = 10μF When the input voltage is approaches the output voltage the input current will increase putting more demand on the input capaci tor. The minimum value of 2.2μF may need to be increased to 4.7μF; higher values will improve performance at lower input voltages, especially when the source impedance is high. The input capacitor should be placed as close as possible to the IC. For maximum stability over temperature and voltage, capacitors with X7R, X5R, or better dielectr ic is recommended. Capacitors w ith Y5V dielectric are not suitable for decoupling in this application and should NOT be used. If higher voltages are used and the C IN is 10μF. This can be an electrolytic capacitor provided a suitable 1µF ceramic c apacitor is also used and positioned as close the VIN of the IC as possible. A suitable capacitor would be NACEW100M1006.3x8TR13F. The following web sites are useful when finding alternatives: www.murata.com www.niccomp.com www.kemet.com Inductor Selection Recommended inductor values for the ZXLD1362 are in the range 68μH to 220μH. Higher values of inductance are recommended at higher supply voltages in order to minimi ze errors due to switching delays, whic h result in increased ripple and lower efficiency. Higher values of inductance also result in a smaller change in output current over the supply voltage range. (see graphs pages 10 - 17). The inductor shoul d be mounted as close to the device as po ssible with low resistance connections t o the LX and VIN pins. The chosen coil should have a saturation current higher than the peak output current and a continuous current rating above the required mean output current. Suitable coils for use with the ZXLD1362 may be selected from th e MSS range manufactured by Coilcraft, or the NPIS range manufa ctured by NIC components. The following websites may be useful in finding suitable components. www.coilcraft.com www.niccomp.com www.wuerth-elektronik.de The inductor value should be chosen to maintain operating duty cy cle and switch 'on'/'off' times within the specified limits ov er the supply voltage and load current range.

Document number: DS33472 Rev. 6 - 2 20 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Application Information (cont.) The graph Figure 3 below can be used to select a recommended i nductor based on maintaining the ZXLD1362 case temperature below 60°C. For detailed performance characteristics for the inductor values 68, 100, 150 and 220μH see graphs on pages 10-17. Figure 3 ZXLD1362 Minimum Recommended Inductor Diode Selection For maximum efficiency and performance, the rectifier (D1) should be a fast low capac itance Schottky diode* with low reverse le akage at the maximum operating voltage and temperature. They also provide better efficiency than silicon diodes, due to a combination of lower forward voltage and reduced recovery time. It is important to select parts with a peak current rating above the peak coil current and a continuous current rating higher t han the maximum output load current. It is very important to consider the reve rse leakage of the diode when operating above +85°C. Excess leaka ge will increase the power dissipation in the device and if close to the load may create a thermal runaway condition. The higher forward voltage and overshoot due to reverse recovery time in silicon diodes will increase the peak voltage on the L X output. If a silicon diode is used, care should be take n to ensure that the total voltage appearing on the LX pin including supply ripple, d oes not exceed the specified maximum value. *A suitable Schottky diode would be PDS3100. Aluminiumboard,2%Accuracy, < 60°CCaseTemperature 0 1 02 03 04 05 06 0 SupplyVoltage (V) Number of LEDs ZXLD1362 Minimum Recommended Inducto r

Document number: DS33472 Rev. 6 - 2 21 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Application Information (cont.) Reducing Output Ripple Peak to peak ripple current in the LED(s) can be reduced, if required, by shunting a capacitor Cled across the LED(s) as shown below: VIN VIN ISENSE LX ZXLD1362 Rs CledLED A value of 1μF will reduce the supply ripple current by a factor three (appr ox.). Proportionally lower ripple can be achieved with higher ca pacitor values. Note that the capacitor will not affect operating frequenc y or efficiency, but it will increase start-up delay, by redu cing the rate of rise of LED voltage. By adding this capacitor the current waveform through the LED(s) changes from a triangular ramp to a more sinusoidal version wi thout altering the mean current value. Operation at Low Supply Voltage Below the under-voltage lockout threshold (VSD) the drive to t he output transistor is turned o ff to prevent device operation wi th excessive on- resistance of the output transistor. The output transistor is not full enhanced until the supply voltage exceeds approximately 17V. At supply voltages between VSD and 17V care must be taken to avoid excessive power dissipation due to the on-resistance. If the supply voltage is always less than 30V continuous an alternative device is available, the ZXLD1360 or the AL8805. Note that when driving loads of two or more LEDs, the forward drop will normally be sufficient to prevent the device from switc hing below approximately 6V. This will minimize the risk of damage to the device.

Document number: DS33472 Rev. 6 - 2 22 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Application Information (cont.) Thermal Considerations When operating the device at high ambient temp eratures, or when driving maximum load current, care must be taken to avoid exceeding the package power dissipation limits. The graph below gives details fo r power derating. This assumes the device to be mounted on a 25mm PCB with 1oz copper standing in still air. -10 10-50 -30 30 90 110 AMBIENT TEMPERATURE (°C) Maximum Power Dissipation 130 15050 70 1100 1000 900 800 500 200 100 700 600 POWER (mW) 400 300 Note that the device power dissipation will most often be a maximum at minimum supply voltage. It will also increase if the efficiency of the circuit is low. This may result from the use of unsuitable coils, or excessive parasitic output capacitance on the switch output. Thermal Compensation of Output Current High luminance LEDs often need to be supplied with a temperature compensated current in order to maintain stable and reliable o peration at all drive levels. The LEDs are usually mounted remotely from the device so, for this reason, the temperature coefficients of the internal circuits for the ZXLD1362 have been optimized to minimize the change in output current when no compensation is employed. If output current compensation is required, it is possible to use an external temperature sensing netwo rk - normally using Negative Temperature C oefficient (NTC) thermistors and/or diodes, mounted very close to the LED(s) . The output of the sensing network can be used to drive the A DJ pin in order to reduce output current with increasing temperature. Layout Considerations LX Pin The LX pin of the device is a fast switching node, so PCB tracks should be kept as short as possible. To minimize ground 'bounc e', the ground pin of the device should be soldered directly to the ground plane. Coil and Decoupling Capacitors and Current Sense Resistor It is particularly important to mount the coil and the input decoupli ng capacitor as close to the de vice pins as possible to mi nimize parasitic resistance and inductance, which will degrade efficiency. It is also important to minimize any track resistance in series with current sense resistor RS. Its best to connect VIN directly to one end of RS and ISENSE directly to the opposite end of RS with no other currents flowing in these tracks. It is important that the cathode current of the Schottky diode does not flow in a track between R S and V IN as this may give an apparent higher measure of current than is actual because of track resistance.

Document number: DS33472 Rev. 6 - 2 23 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Application Information (cont.) ADJ Pin The ADJ pin is a high impedance input for voltages up to 1.35V so , when left floating, PCB tracks to this pin should be as shor t as possible to reduce noise pickup. A 100nF capacitor from the ADJ pin to ground will reduce frequency modulation of the output under these co nditions. An additional series 3.3kΩ resistor can also be used when driving the ADJ pin from an external circuit (see below ). This resistor will provide filtering for low frequency noise and provide protection against high voltage transients. GND ZXLD136 2ADJ 3.3k 100nF GND High Voltage Tracks Avoid running any high voltage tracks close to the ADJ pin, to reduce the risk of leakage currents due to board contamination. The ADJ pin is soft-clamped for voltages above 1.35V to desensitize it to leakage that might raise the ADJ pin voltage and cause excessive out put current. However, a ground ring placed around the ADJ pin is recommended to minimize changes in output current under these conditions. Evaluation PCB ZXLD1362 evaluation boards are available on request and provide quick testing of the ZXLD1362 device. Dimming Output Current Using PWM Low Frequency PWM Mode When the ADJ pin is driven with a low frequency PWM signal (eg 100Hz), with a high level voltage V ADJ and a low level of zero, the output of the internal low pass filter will swing between 0V and V ADJ, causing the input to the shutdown circuit to fall below its turn-off threshold (200mV nom) when the ADJ pin is low. This will cause the output current to be switched on and off at the PWM frequency, resulting in an ave rage output current IOUTavg proportional to the PWM duty cycle. (See Figure 4 - Low frequency PWM operating waveforms). Figure 4 Low Frequency PWM Operating Waveforms The average value of output current in this mode is given by: IOUTavg = 0.1DPWM/RS [for DPWM >0.001] This mode is preferable if optimum LED 'w hiteness' is required. It will also provi de the widest possible dimming range (approx. 1000:1) and higher efficiency at the expense of greater output ripple.

Document number: DS33472 Rev. 6 - 2 24 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362

Ordering Information

(Note 12) Part Mark Package Code Packaging Reel size (mm) Reel width (mm) Quantity per reel Part Number Suffix Qualification (Note 11) ZXLD1362ET5TA 1362 ET5 TSOT25 180 8 3000 TA AEC-Q100 grade 1 ZXLD1362QET5TA 1362 ET5 TSOT25 180 8 3000 TA Automotive Grade Note: 11. ZXLD1362QET5 is classified as “Automotive Grade” a nd supports PPAP documentation. See ZXLD1362Q datasheet for more information. Marking Information Package Outline Dimensions Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for latest version. TSOT25 Dim Min Max Typ A − 1.00 − A1 0.01 0.10 − A2 0.84 0.90 − D − − 2.90 E − − 2.80 E1 − − 1.60 b 0.30 0.45 − c 0.12 0.20 − e − − 0.95 e1 − − 1.90 L 0.30 0.50 L2 − − 0.25 θ 0° 8° 4° θ1 4° 12° − All Dimensions in mm c L E1 E D e 5x b θ 4x 1 θ A

Document number: DS33472 Rev. 6 - 2 25 of 25 www.diodes.com March 2014 © Diodes Incorporated A Product Line of Diodes Incorporated ZXLD1362 Suggested Pad Layout Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for latest version. IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). Diodes Incorporated and its subsidiaries reserve the right to ma ke modifications, enhancements, im provements, corrections or ot her changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the application or use of this document or any product described her ein; neither does Diodes Inco rporated convey any license under its patent or trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporat ed and all the companies whose products are represented on Diodes Incorporated website, harmless against all damages. Diodes Incorporated does not warrant or accept any liability what soever in respect of any pr oducts purchased through unauthoriz ed sales channel. Should Customers purchase or use Diodes In corporated products for any unintended or unauthorized application, Customers shall i ndemnify and hold Diodes Incorporated and its repres entatives harmless against all claims, dam ages, expenses, and attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application. Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings noted herein may also be covered by one or more United States, international or foreign trademarks. This document is written in English but may be translated into mu ltiple languages for reference. Only the English version of this document is the final and determinative format released by Diodes Incorporated. LIFE SUPPORT Diodes Incorporated products are specifically not authorized for use as critical co mponents in life support devices or systems without the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein: A. Life support devices or systems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failure to perform when prope rly used in accordance with inst ructions for use provided in the labeling can be reasonably expected to result in significant injury to the user. B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning the ir products and any use of Diodes Incorporated products in such safety-critica l, life support devices or systems, notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporate d and its representatives against any damages arising out of the use of Diodes Incorporat ed products in such safety-critical, life support devices or systems. Copyright © 2014, Diodes Incorporated www.diodes.com Dimensions Value (in mm) C 0.950 X 0.700 Y 1.000 Y1 3.199 C C X (5x) Y (5x)