ZXLD1366Q_18 DIODES | Alldatasheet
Document overview
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Technical content
Features
Typically Better than 0.8% Output Current Accuracy Simple and With Low Part Count Single Pin O n/Off and Brightness Control Using DC Voltage or PWM PWM Resolution up to 1000:1 High Efficiency (up to 97%) Switching Frequencies up to 1MHz Wide Input Voltage Range: 6V to 60V Inherent O pen-Circuit LED Protection Available in Thermally Enhanced Green Molding Packages V-DFN3030-6 JA = +44°C/W SO-8EP JA = +45°C/W TSOT25 JA = +82°C/W Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. “Green” Device (Note 3) Qualified to AEC-Q100 Standards for High Reliability PPAP Capable (Note 4)
Applications
Automotive Lighting: Internal Door Lights Rear Fog Lamps Position Lights Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS ), 2011/65/EU (RoHS 2) & 2015/863/EU (RoHS 3) compliant. 2. See https://www.diodes.com/quality/lead- free/ for more information about Diodes Incorporated’s definitions of H alogen- and Antimony-free, "Green" and Lead-free. 3. Halogen- and Antimony- free "Green” products are defined as those which contain <900ppm bro mine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. (TOP VIEW) TSOT25 ISENSE VIN 3 4 ADJ GND LX 3 4 U-DFN3030-6 (TOP VIEW) LX GND ADJ VIN ISENSE GND (TOP VIEW) SO-8EP LX GND GND ADJ VIN GND GND ISENSE
Figure 1. Pin Connection for TSOT25 Package
- Leave floating for normal operation. (VADJ = VREF = 1.25V giving nominal average output current IOUTnom = 0.2V/RS)
- Drive to voltage below 0.2V to turn off output current
- Drive with DC voltage (0.3V < V ADJ < 2.5V) to adjust output current from 25% to 200% of IOUTnom
- Connect a capacitor from this pin to ground to set so ft-start time. Soft start time increases approximately 0.2ms/nF ISENSE 4 5 4 Connect resistor RS from this pin to VIN to define nominal average output current IOUTnom = 0.2V/RS. (Note: RSMIN = 0.2V with ADJ pin open-circuit) VIN 5 8 6 Input Voltage (6V to 60V). Decouple to ground with 4.7µF of higher X7R ceramic capacitor close to device. Pad Pad Pad Exposed Pad (EP) - connected to device substrate. To improve thermal impedance of package the EP must be connected to power ground but should not be used as the 0V (GND) current path. It can be left floating but must not be connected to any other voltage other than 0V. Low voltage detector Voltage regulator LX MN ISENSE Adj Gnd VIN VIN 50K 20K 1.25V 1.35V 0.2V 600KHz R4 R5 5 4 1 RS 4.7 礔 ADJ GND 47µF
Document number: DS37078 Rev. 2 - 2 3 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Absolute Maximum Ratings (Note 5) (@TA = +25°C, unless otherwise specified.) Symbol Parameter Rating Unit VIN Input Voltage -0.3 to +65 V VSENSE ISENSE Voltage (Note 6) +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 25) TSOT25 1 W SO-8EP 2.2 V-DFN3030-6 1.8 TOP Operating Temperature -40 to +125 ° C TST Storage Temperature -55 to +150 ° C TJ MAX Junction Temperature +150 ° C ESD Susceptibility TSOT25 SO-8EP V-DFN3030-6 — HBM Human Body Model <250 (Note 7) <250 500 V CDM Charged Device Model 1000 1000 1000 V Notes: 5. All voltages unless otherwise stated are measured with respect to GND. 6. V SENSE is measured with respect to VIN. 7. Although value is reduced, no physical change to device. 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 device at conditions between maximum re commended 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. Semiconductor devices are ESD sensitive and may be damaged by exposu re to ESD events. Suitable ESD precautions should be take n when handling and transporting these devices. The human body model is a 100pF capacitor discharge through a 1.5kΩ resistor pin. Thermal Resistance Symbol Parameter Rating Unit TSOT25 SO-8EP V-DFN3030-6 JA Junction to Ambient 82 45 44 °C/W JB Junction to Board 33 — — JC Junction to Case — 7 14 Recommended Operating Conditions Symbol Parameter Min Max Unit VIN Input Voltage (Note 8) 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 9) 0.3 2.5 V VADJOFF DC Voltage on ADJ Pin to Ensure Devices is Off — 0.25 V tOFFMIN Minimum Switch Off-time — 800 ns tONMIN Minimum Switch On-time — 800 ns fLX MAX Recommended Maximum Operating Frequency (Note 10) — 625 kHz DLX Duty Cycle Range 0.01 0.99 — DLX(LIMIT) Recommended Duty Cycle Range of Output Switch at fLXMAX 0.3 0.7 — TOP Operating Temperature Range (Junction and Ambient) -40 +125 ° C Notes: 8. V IN > 16V to fully enhance output transistor. Otherwise out current must be derated - see graphs. Operation at low supply may cause excessive h eating due to increased on-resistance. 9. 100% brightness corresponds to V ADJ = VADJ(nom) = VREF. Driving the ADJ pin above VREF will increase the VSENSE threshold and output current proportionally. 10. ZXLD1366Q will operate at higher frequencies but accuracy will be affected due to propagation delays.
Document number: DS37078 Rev. 2 - 2 4 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Electrical Characteristics (Test conditions: (@ VIN = 24V, TA = +25°C, unless otherwise specified.)) Symbol Parameter Condition Min Typ Max Unit VSU Internal Regulator Start-up Threshold — — 4.85 5.20 V VSD Internal Regulator Shutdown Threshold — 4.40 4.75 — V IINQoff Quiescent Supply Current With Output Off ADJ pin grounded — 65 108 µ A IINQon Quiescent Supply Current With Output Switching (Note 12) ADJ pin floating, L = 68µH,
3 LEDs, f = 260kHz
— 1.6 — mA VSENSE Mean Current Sense Threshold Voltage (Defines LED Current Setting Accuracy) Measured on ISENSE pin with respect to VIN VADJ = 1.25V; VIN = 18V 195 200 205 mV VSENSEHYS Sense Threshold Hysteresis — — ±15 — % ISENSE ISENSE Pin Input Current VSENSE = VIN -0.2V — 4 10 µ A VREF Internal Reference Voltage Measured on ADJ pin with pin floating — 1.25 — V VREF/T Temperature Coefficient of VREF — — 50 — ppm/°C VADJ External Control Voltage Range on ADJ Pin for DC Brightness Control (Note 11) — 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 0.20 0.27 V VADJon DC Voltage on ADJ Pin to Switch Device from Quiescent (Off) State to Active (On) State VADJ rising 0.20 0.25 0.30 V RADJ Resistance between ADJ Pin and VREF 0 < VADJ < VREF VADJ > VREF +100mV 10.4 14.2 18.0 kΩ ILXmean Continuous LX Switch Current — — — 1 A RLX LX Switch ‘On’ Resistance @ ILX = 1A — 0.50 0.75 Ω ILX(leak) LX Switch Leakage Current — — — 5 µ A 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 — 1.000 V — Brightness Control Range — — 1000:1 — — DCADJ DC Brightness Control Range (Note 13) — 5:1 — — tSS Soft-start Ttime 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 (0.2V) IOUT = 1A @ VLED = 3.6V Driving 3 LEDs — 260 — kHz tONmin Minimum Switch ‘ON’ Time LX switch ‘ON’ — 130 — ns tOFFmin Minimum Switch ‘OFF’ Time LX switch ‘OFF’ — 70 — ns Notes: 11. 100% brightness corresponds to VADJ = VADJ(nom) = VREF. Driving the ADJ pin above VREF will increase the VSENSE threshold and output current proportionally. 12. Static current of device is approximately 700µA, see graph, P age 15.
The device, in conjunction with the coil (L1) and current sense resistor (RS), forms a self-oscillating continuous-mode buck converter. Figure 2. Theoretical Operating Waveforms (+) input of the comparator. from VIN to ground, via RS, L1 and the LED(s). The current rises at a rate determined by VIN and L1 to produce a voltage ramp (VSENSE) across RS. resistor R3 to provide a controlled amount of hysteresis. The hysteresis is set by R3 to be nominally 15% of VADJ. switches high again. This cycle of events repeats, with the comparator input ramping between limits of VADJ ± 15%. Nominal ripple current is ±30mV/RS.
Document number: DS37078 Rev. 2 - 2 6 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Device Description (Cont.) Actual operating waveforms VIN = 15V, RS = 0.2Ω, L = 68µH Normal Operation. Output Current (Ch. 3) and LX Voltage (Ch. 2) VIN = 30V, RS = 0.2Ω, L = 68µH Normal Operation. Output Current (Ch. 3) and LX Voltage (Ch. 2) VIN = 60V, RS = 0.2Ω, L = 68µH Normal Operation. Output Current (Ch. 3) and LX Voltage (Ch. 2) Adjusting Output Current The device contains a low pass filter between the ADJ pin and the threshold comparator and an internal current limiting r esistor (50kΩ nom) between ADJ and the internal reference voltage. This allo ws the ADJ pin to be overdriven with either DC or pulse signals to change the V SENSE 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 circu it. When the input voltage to this circuit falls below the t hreshold (0.2V nom.), the internal regulator and the output switch are turned off. The voltage reference remains powered during shutdown to p rovide the bias current for the shutdown circuit. Quiescent supply current during shutdown is nominally 60μA and switch leakage is below 5μA.
Document number: DS37078 Rev. 2 - 2 7 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Typical Operating Conditions 0 10 20 30 40 50 60 SUPPLY VOLTAGE (V) Output Current, L = 68礖 1.100 1.080 1.060 1.040 1.020 1.000
0.980 OUTPUT CURRENT (A)
1 LED
3 LEDs
5 LEDs
7 LEDs
9 LEDs
11 LEDs
13 LEDs
15 LEDs
SUPPLY VOLTAGE (V) Output Current Deviation, L = 68礖 OUTPUT CURRENT DEVIATION (%) -10 SUPPLY VOLTAGE (V) Efficiency, L = 68 礖 100
70 EFFICIENCY (%)
Output Current, L = 68µ H Output Current Deviation, L = 68µ H Efficiency, L = 68µ H
Document number: DS37078 Rev. 2 - 2 8 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Typical Operating Conditions (Cont.) SUPPLY VOLTAGE (V) Switching Frequency, L = 68 礖 500 450 400 150 100 SWITCHING FREQUENCY (kHz) 350 300 250 200 SUPPLY VOLTAGE (V) Duty Cycle, L = 68 礖 100 DUTY CYCLE (%) µ H Switching Frequency, L = 68µ H Duty Cycle, L = 68µ H
Document number: DS37078 Rev. 2 - 2 9 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Typical Operating Conditions (Cont.) SUPPLY VOLTAGE (V) Output Current, L = 100礖 1.100 1.080 1.060 1.040 1.020 1.000 0.960 SUPPLY VOLTAGE (V) Output Current Deviation, L = 100 礖 OUTPUT CURRENT DEVIATION (%) -10 SUPPLY VOLTAGE (V) Efficiency, L = 100礖 Output Current, L = 100µ H Efficiency, L = 100µ H Output Current Deviation, L = 100µ H
Document number: DS37078 Rev. 2 - 2 10 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Typical Operating Conditions (Cont.) SUPPLY VOLTAGE (V) Switching Frequency, L = 100礖 500 450 400 150 100 SWITCHING FREQUENCY (kHz) 350 300 250 200 SUPPLY VOLTAGE (V) Duty Cycle, L = 100 礖 100 DUTY CYCLE (%) Switching Frequency, L = 100µ H Duty Cycle, L = 100µ H
Document number: DS37078 Rev. 2 - 2 11 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Typical Operating Conditions (Cont.) 0 10 20 30 40 50 60 SUPPLY VOLTAGE (V) Output Current, L = 150礖 1.100 1.080 1.060 1.040 1.020 1.000 SUPPLY VOLTAGE (V) Output Current Deviation, L = 150礖 OUTPUT CURRENT DEVIATION (%) -10 SUPPLY VOLTAGE (V) Efficiency, L = 150礖 Output Current, L = 150µ H Output Current Deviation, L = 150µ H Efficiency, L = 150µ H
Document number: DS37078 Rev. 2 - 2 12 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Typical Operating Conditions (Cont.) SWITCHING FREQUENCY (kHz) 350 300 250 200 0 10 20 30 40 50 60 SUPPLY VOLTAGE (V) Switching Frequency, L = 150 礖 100 DUTY CYCLE (%) 0 10 20 30 40 50 60 SUPPLY VOLTAGE (V) Duty Cycle, L = 150 礖 µ H Duty Cycle, L = 150µ H Switching Frequency, L = 150µ H
Document number: DS37078 Rev. 2 - 2 13 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Typical Operating Conditions (Cont.) 0 10 20 30 40 50 60 SUPPLY VOLTAGE (V) Output Current, L = 220礖 1.100 1.080 1.060 1.040 1.020 1.000 SUPPLY VOLTAGE (V) Output Current Deviation, L = 220礖 OUTPUT CURRENT DEVIATION (%) -10 SUPPLY VOLTAGE (V) Efficiency, L = 220礖 EFFICIENCY (%) Output Current, L = 220µ H Output Current Deviation, L = 220µ H Efficiency, L = 220µ H
Document number: DS37078 Rev. 2 - 2 14 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Typical Operating Conditions (Cont.) 0 10 20 30 40 50 60 SUPPLY VOLTAGE (V) Switching Frequency, L = 220礖 500 450 400 150 100 SWITCHING FREQUENCY (kHz) 350 300 250 200 SUPPLY VOLTAGE (V) Duty Cycle, L = 220礖 100 DUTY CYCLE (%) Duty Cycle, L = 220µ H Switching Frequency, L = 220µ H
Document number: DS37078 Rev. 2 - 2 15 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Typical Operating Conditions (Cont.) ADJ PIN VOLTAGE (V) LED Current vs. ADJ 0 321 1200 1000 800 600 400 200 LED CURRENT (mA) R = 200m R = 300m R = 680m SUPPLY VOLTAGE (V) 0 705010 20 30 40 60 800 500 400 300 200 100 SUPPLY CURRENT (mA) 600 700 SUPPLY VOLTAGE (V) 0 705010 20 30 40 60 1.2430 1.2415 1.2410 1.2405 1.2400 1.2395 1.2380 ADJ PIN VOLTAGE (V) 1.2420 1.2425 1.2385 1.2390 SUPPLY VOLTAGE (V) 0 705010 20 30 40 60 SHUTDOWN CURRENT (mA) SUPPLY CURRENT (µA)
Document number: DS37078 Rev. 2 - 2 16 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Typical Operating Conditions (Cont.) 0 5 30 3510 15 20 25 SUPPLY VOLTAGE (V) LX On-Resistance vs. Supply Voltage -40癈 20癈 150癈 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 ON-RESISTANCE ( ) 12V 20V 30V -50 0 20050 100 150 TEMPERATURE (癈) V vs. TemperatureADJ 1.262 1.260 1.258 1.256 1.254 1.250 1.248 1.246 1.244 V (V)ADJ1.252 12V 30V 20V -50 0 20050 100 150 DIE TEMPERATURE (癈 ) LX On-Resisitance vs. Die Temperature 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 ON-RESISTANCE ( ) (° C) (° C) -40° C 20° C 150° C
Document number: DS37078 Rev. 2 - 2 17 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q
Application Information
Setting Nominal Average Output Current with External Resistor RS The nominal average output current in the LED(s) is det ermined by the value of the external current sense resi stor (RS) connected between V IN and ISENSE and is given by: IOUTnom = 0.2/RS for RS ≥ 0.2Ω The table below gives values of nominal average output current for several preferred values of current sense resistor (RS) in the typical application circuit shown on page 1: RS (Ω) Nominal Average Output Current (mA) 0.20 1,000 0.27 740 0.56 357 The above values assume that the ADJ pin is floating and at a nominal voltage of V REF (= 1.25V). Note that R S = 0.2 Ω 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 ab ove or below the nominal average value defined by RS. The nominal average output current in this case is given by: IOUTdc = (VADJ /1.25) x (0.2/RS) for 0.3 < VADJ < 2.5V Note that the 100% brightness setting corresponds to VADJ = VREF. When driving the ADJ pin above 1.25V, RS 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 DPWM 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:
Document number: DS37078 Rev. 2 - 2 18 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Application Information (Cont.) Driving the ADJ Input via Open Collector Transistor The recommended method of driving the ADJ pin and controlling th e amplitude of the PWM waveform is to use a small NPN s witching transistor as shown below: 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: If the NMOS transistor within the microcontroller has high Ga te / Drain capacitance, this arrangement can inject a neg ative spike into the ADJ input of the ZXLD1366Q and cause erratic operation, but t he addition of a Schottky clamp diode (eg Diodes Incorpora ted SD103CWS) to ground and inclusion of a series resistor (3.3k) will prevent this. See the section on PWM dimming for more details of the var ious 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 low standby level of 65μA 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 15 graphs for details).
Document number: DS37078 Rev. 2 - 2 19 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Application Information (Cont.) 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 o f the control voltage at the input of the comparator. Add ing capacitance increases this delay by approximately 0.2ms/nF. The graph below shows the variation of soft-start time for different values of capacitor. Actual Operating Waveform [VIN = 60V, RS = 0.2Ω, L = 68μH, 22nF on ADJ] Soft-start operation, LX voltage (CH2) and Output current (CH3) using a 22nF external capacitor on the ADJ pin. 60 80 100 1200 20 40 CAPACITANCE (nF) Soft-Start Time vs. Capacitance form ADJ to Ground SOFT-START TIME (ms)
Document number: DS37078 Rev. 2 - 2 20 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Application Information (Cont.) VIN Capacitor Selection A low ESR capacitor should be used for input decoupling, a s the ESR of this capacitor appears in series with the su pply 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 close to the output voltage, the input current increases which puts more demand on the input capacitor. The minimum value of 2.2μF may need to be increased to 4.7μF; higher values will improve performance at lower input voltages, esp ecially 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 dielectric is recommended. Capacitors with Y5V dielectric are not suitable for decoupling in this application and should not be used. When higher voltages are used with the C IN = 10μF, an electrolytic capacitor can be used provided t hat a suitable 1µF ceramic capacitor is also used and positioned as close to the VIN pin as possible. A suitable capacitor would be NACEW100M1006.3x8TR13F (NIC Components). 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 ZXLD1366Q are in the range 68μH to 220μH. Higher values of inductance are recommended at higher supply voltages in order to minimize errors due to switching delays, which result in increased ripple and lower efficiency. Higher values of inductance also result in a smaller change in output current over t he supply voltage range (see graphs pages 7-14). The inductor should be mounted as close to the device as possible with low resistance conn ections to the LX and VIN pins. The chosen coil should have a saturation current higher tha n the peak output current and a continuous current r ating above the required mean output current. Suitable coils for use with the ZXLD1366Q may be selected from the MSS range manufactured by Coilcraft, or the NP IS range manufactured 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 cycle and switch 'on'/'off' time within the specified li mits over the supply voltage and load current range. Figures 3, 4 and 5 (below), can be used to select a recommended inductor based on maintaining the ZXLD1366Q case temperature below +60°C. For detailed performance characteristics for the inductor values 68, 100, 150 and 220μH see graphs on pages 7-14.
Figure 5. ZXLD1366Q Minimum Recommended Inductor (V-DFN3030-6)
Document number: DS37078 Rev. 2 - 2 23 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Application Information (Cont.) Diode Selection For maximum efficiency and performance, the rectifier (D1) should be a fast, low capacitance Schottky diode* with low reverse leakage 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 than the maximum output load current. It is very important to consider the reverse leakage of the diode when operating above +85°C. Excess leakage 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 LX output. If a silicon diode is used, care should be taken to ensure that the t otal voltage appearing on the LX pin including supply ripple, does not exceed the specified maximum value. *A suitable Schottky diode would be PDS3100Q (Diodes Incorporated)
Figure 6. Reduced Output Ripple voltages between VSD and 17V, care must be taken to avoid excessive power dissipation due to the on-resistance. approximately 6V. This will minimize the risk of damage to the device.
with 1oz copper standing in still air. is low. This may result from the use of unsuitable coils, or excessive parasitic output capacitance on the switch output. examples used in the ZXLD1366Q evaluation boards. Figure 7. Suggested Layout for SO-8EP Package The use of vias for the TSOT25 package should also be implemented to guarantee an effective thermal path.
Document number: DS37078 Rev. 2 - 2 26 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Application Information (Cont.) Thermal Compensation of Output Current High luminance LEDs often need to be supplied with a tempe rature compensated current in order to maintain stable and reliable operation 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 ZXLD1366Q is 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 netw ork normally, using Negative Temperature Coefficient (NTC) ther mistors and/or diodes, mounted very close to the LED(s). The output of the sen sing network can be used to drive the ADJ 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 t racks should be kept as short as possible. To minimize ground 'bounce', 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 decoupling capacitor as close to the device pi ns as possible to minimize parasitic resistance and inductance, which will degrade efficiency. I t is also important to minimize any track resistance in series with current sense resistor RS. It is best to connect VIN directly to one end of R S 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 actually present, because of track resistance. ADJ Pin The ADJ pin is a high-impedance input for voltages up to 1.3 5V, so when left floating, PCB tracks to this pin should be as short as possible to reduce noise pickup. A 100nF capacitor from the ADJ pin to ground will reduce frequency modulation of the output under these conditions. An additional series 3.3kΩ resistor can also be used when driving the ADJ pin from a n external circuit. This resistor will provide filtering for low - frequency noise and provide protection against high-voltage transients. High-Voltage Tracks Avoid running any high-voltage tracks close to the ADJ pin to reduce the risk of leakage currents due to board con tamination. 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 output current. However, a ground ring placed around the ADJ pin is recommended to minimize changes in output current under these conditions. Evaluation PCB ZXLD1366Q evaluation boards are available upon request. Terminals allow users to interface the boards to their preferred LED products.
IOUTavg proportional to the PWM duty cycle. (See Figure 8 - Low frequency PWM operating waveforms). efficiency at the expense of greater output ripple. Figure 8. Low Frequency PWM Operating Waveforms
pin will rise to VIN and the LX pin will then fall to GND. No excessive voltages will be seen by the ZXLD1366Q. reverse voltage across the inductor is now just the Schot tky diode voltage (See Figure 9) causing a much slower decay in inductor current. Figure 9. Switching Characteristics (Normal Open to Short LED Chain)
Document number: DS37078 Rev. 2 - 2 29 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q
Ordering Information
(Note 14) Pack Code Reel Size (inches) Reel Width (mm) Quantity Per Reel Part Number Suffix Qualification (Note 15) ZXLD1366QDACTC V-DFN3030-6 DAC 13 8 3,000 TC Automotive Compliant ZXLD1366QEN8TC SO-8EP EN8 13 12 2,500 TC Automotive Compliant ZXLD1366QET5TA TSOT25 ET5 7 8 3,000 TA Automotive Compliant Notes: 14. For packaging details, go to our website at https://www.diod es.com/design/support/packaging/diodes-packaging/. 15. ZXLD1366Q has been qualified to AEC-Q100 grade 1 and is classified as “Automotive Compliant” supporting PPAP documentation. See ZXLD1366 datasheet for commercial qualified versions. Marking Information (1) TSOT25 (2) V-DFN3030-6 (3) SO-8EP 1366 : Identification Code ZXLD1366 : Part Number YY : Year : 17, 18, 19~ WW : Week : 01 to 52; 52 represents weeks 52 and 53
Document number: DS37078 Rev. 2 - 2 30 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Package Outline Dimensions Please see http://www.diodes.com/package-outlines.html for the latest version. 1) Package Type : TSOT25 2) Package Type: V-DFN3030-6 3) Package Type: SO-8EP TSOT25 Dim Min Max Typ A - 1.00 - A1 0.01 0.10 - A2 0.84 0.90 - b 0.30 0.45 - c 0.12 0.20 - D - - 2.90 E - - 2.80 E1 - - 1.60 e 0.95 BSC e1 1.90 BSC L 0.30 0.50 L2 0.25 BSC θ 0° 8° 4° θ1 4° 12° - All Dimensions in mm V-DFN3030-6 Dim Min Max Typ A 0.80 0.90 0.85 A1 0 0.05 - A3 - - 0.203 b 0.30 0.40 0.35 D 2.95 3.05 3.00 D2 1.95 2.05 2.00 E 2.95 3.05 3.00 E2 1.15 1.25 1.20 e - - 0.95 e1 - - 1.90 L 0.45 0.55 0.50 All Dimensions in mm SO-8EP Dim Min Max Typ A 1.40 1.50 1.45 A1 0.00 0.13 - b 0.30 0.50 0.40 C 0.15 0.25 0.20 D 4.85 4.95 4.90 E 3.80 3.90 3.85 E0 3.85 3.95 3.90 E1 5.90 6.10 6.00 e - - 1.27 F 2.75 3.35 3.05 H 2.11 2.71 2.41 L 0.62 0.82 0.72 N - - 0.35 Q 0.60 0.70 0.65 All Dimensions in mm Chamfer 0.300X45° Pin #1 ID E D Seating Plane L b e A b e E1A 9° ( All side) 4°±3° C Q N 45° R 0.1 D E L Seating Plane Gauge Plane F H EXPOSED PAD D E1/2 E E/2 e A Seating Plane0 L Gauge Plane 01( 4x) 01( 4x) c b Seating Plane
Document number: DS37078 Rev. 2 - 2 31 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q Suggested Pad Layout Please see http://www.diodes.com/package-outlines.html for the latest version. 1) Package Type : TSOT25 2) Package Type: V-DFN3030-6 Dimensions Value (in mm) C 0.950 X 0.450 X1 2.100 Y 0.630 Y1 1.300 Y2 3.160 3) Package Type: SO-8EP Dimensions Value (in mm) C 0.950 X 0.700 Y 1.000 Y1 3.199 Dimensions Value (in mm) C 1.270 X 0.802 X1 3.502 X2 4.612 Y 1.505 Y1 2.613 Y2 6.500 C X Y Y XC C - 0.329 C X Y
Document number: DS37078 Rev. 2 - 2 32 of 32 www.diodes.com April 2018 © Diodes Incorporated ZXLD1366Q IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRES S OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF ME RCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, correction s or other changes without further notice to this document and any produ ct described herein. Diodes Incorporated does not assume any liability arising out of the application or use of this document or any product des cribed herein; neither does Diodes Incorporated convey a ny license under its patent or trademark rights, nor the rights of others. Any Custome r or user of this document or products described here in in such applications shall assume all risks of such use and will agree to hold Diodes Incorpo rated and all the companies whose products are represe nted on Diodes Incorporated website, harmless against all damages. Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel. Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application. Products described herein may be covered by one or more United States, international or foreign patents pending. Pro duct 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 int o multiple 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 components in life support dev ices 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 perfor m when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in signi ficant 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 lif e support devices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of Diodes Incorporated products in such safety-criti cal, life support devices or systems, notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorpo rated. Further, Customers must fully indemnify Diodes Incor porated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems. Copyright © 2018, Diodes Incorporated www.diodes.com