AL8805

AL8805

Document overview

• Manufacturer or author: Diodes Incorporated
• PDF pages: 17

Technical content

Features

• LED Driving Current up to 1A
• Better than 5% Accuracy
• High Efficiency up to 98%
• Operating Input Voltage from 6V to 36V
• High Switching Frequency up to 1MHz
• PWM/DC Input for Dimming Control
• Built-In Output Open-Circuit Protection
• SOT25: Available in “Green” Molding Compound (No Br,Sb) with lead Free Finish/ RoHS Compliant  Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)  Halogen and Antimony Free. “Green” Device (Note 3) Pin Assignments

4 SET

5 VINSW 1

(Top View) SOT25

Applications

• MR16 Lamps
• General Illumination Lamps Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See http://www.diodes.com for more information about Diodes Incorporated’s definitions of Hal ogen- 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 Applications Circuit SW GND SET VIN CTRL Vsupply AL8805 D2 D3 D4 D5 NOT RECOMMENDED FOR NEW DESIGN USE AL8860 OR AL8861

Document number: DS43562 Rev. 5 - 3 2 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805 Pin Descriptions Pin Number Pin Name Function 1 SW Switch Pin. Connect inductor/freewheeling diode here, minimizing track length at this pin to reduce EMI.

2 GND GND Pin

3 CTRL

Dimming and On/Off Control Input.

• Leave floating for normal operation. (VCTRL = VREF = 2.5V giving nominal average output current IOUTnom = 0.1/RS)
• Drive to voltage below 0.4V to turn off output current
• Drive with DC voltage (0.5V < VCTRL < 2.5V) to adjust output current from 20% to 100% of IOUTnom
• A PWM signal (low level ≤ 0.4V and high level > 2.6; transition times less than 1us) allows the output current to be adjusted below the level set by the resistor connected to SET input pin. 4 SET Set Nominal Output Current Pin. Configure the output current of the device. 5 VIN Input Supply Pin. Must be locally decoupled to GND with > 2.2µF X7R ceramic capacitor – see applications section for more information. Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.) Symbol Parameter Ratings Unit ESD HBM Human Body Model ESD Protection 2.5 kV ESD MM Machine Model ESD Protection 200 V VIN Continuous VIN Pin Voltage Relative to GND -0.3 to 40 V VSET SET Pin Voltage Relative to VIN Pin -5 to +0.3 V VSW SW Voltage Relative to GND -0.3 to 40 V VCTRL CTRL Pin Input Voltage -0.3 to 6 V ISW-DC DC or RMS Switch current 1.25 A ISW-PK Peak Switch Current (<10%) 2.5 A TJ Junction Temperature 150 °C TLEAD Lead Temperature Soldering 300 °C TST Storage Temperature Range -65 to +150 °C Caution: Stresses greater than the 'Absolute Maximum Ratings' specified above, may cause permanent damage to the device. These are stress ratings only; functional operation of the device at these or any other conditions exceeding those indicated in this specification is not im plied. 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 exposure to ESD events. Suitable ESD precautions should be taken when handling and transporting these devices Recommended Operating Conditions (@TA = +25°C, unless otherwise specified.) Symbol Parameter Min Max Unit VIN Operating Input Voltage relative to GND 6.0 36 V VCTRLH Voltage High for PWM Dimming Relative to GND 2.6 5.5 V VCTRLDC Voltage Range for 20% to 100% DC Dimming Relative to GND 0.5 2.5 V VCTRLL Voltage Low for PWM Dimming Relative to GND 0 0.4 V ISW Continuous Switch Current — 1 A TJ Junction Temperature Range -40 125 °C

Document number: DS43562 Rev. 5 - 3 3 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805 Electrical Characteristics (VIN = 12, @TA = +25°C, unless otherwise specified.) Symbol Parameter Conditions Min Typ Max Unit VINSU Internal Regulator Start Up Threshold VIN rising 5.9 V VINSH Internal Regulator Hysteresis Threshold VIN falling 100 300 mV IQ Quiescent Current Output not switching (Note 4) 350 µA IS Input Supply Current CTRL pin floating f = 250kHz 1.8 5 mA VTH Set Current Threshold Voltage 95 100 105 mV VTH-H Set Threshold Hysteresis ±20 mV ISET SET Pin Input Current VSET = VIN-0.1 16 22 µA RCTRL CTRL Pin Input Resistance Referred to internal reference 50 kΩ VREF Internal Reference Voltage 2.5 V RDS(on) On Resistance of SW MOSFET ISW = 1A 0.25 0.4 Ω ISW_Leakage Switch Leakage Current VIN = 30V 0.5 μA fOSC Switching Frequency 1 MHz θJA Thermal Resistance Junction-to- Ambient (Note 5) SOT25 (Note 6) 250 °C/W ΨJB Thermal Resistance Junction-to-Lead (Note 7) SOT25 50 Notes: 4. AL8805 does not have a low power standby mode but current consumption is reduced when output switch is inhibited: V SENSE = 0V. Parameter is tested with VCTRL ≤ 2.5V 5. Refer to figure 34 for the device derating curve. 6. Test condition for SOT25: Device mounted on FR-4 PCB (25mm x 25mm 1oz copper, minimum recommended pad layout on top layer and thermal vias to bottom layer ground plane. For better thermal performance, larger copper pad for heat -sink is needed. 7. As SOT25 doesn’t have an exposed tab or exposed pad the majority of heat flow is though pin 2 down to ground.

1 LED

Figure 5. V vs. Input Voltage

Document number: DS43562 Rev. 5 - 3 5 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805 Typical Performance Characteristics (cont.) (@TA = +25°C, unless otherwise specified.) Typical Performance Characteristics (cont.) (@TA = +25°C, unless otherwise specified.) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 LED CURRENT (A) PWM DUTY CYCLE Figure 7 I vs. PWM Duty CycleLED LED CURRENT ERROR (%) 120 180 240 300 6 12 18 24 30 36 V (V) Figure 8 SW R vs. Input Voltage IN DS(ON) R (m )DS(ON) Ω V = Open V = V T = 25 C CTRL SET IN A ° 100 150 200 250 300 350 400 -40 -15 10 35 60 85 110 AMBIENT TEMPERATURE (°C) Figure 9 SW R vs. TemperatureDS(ON) R (m )DS(ON) Ω 100 105 110 115 120 125 130 TIME (µs) Figure 10 SW Output Switching Characteristics VSW V (mV)SENSE R = 150m L = 68µH V = 12V

1 LED Load

Ω VSW VSENSE ILED VSW VCTRL 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 50 100 150 200 Time (µs) Figure 11 PWM Dimming 20Duty Cycle = 5% SWITCH and CTRL VOLTAGE (V) LED CURRENT (A) R = 150m , L =68µH, V = 12V, 1LED Load, T =25 CSET IN AΩ° 6 9 12 15 18 21 24 27 30 INPUT VOLTAGE (V) Figure 12 Duty Cycle vs. Input Voltage DUTY CYCLE L = 33µH R = 150m T = 25°C

2 LED

S A Ω 33 36

Document number: DS43562 Rev. 5 - 3 6 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805 Typical Performance Characteristics (cont.) (670mA LED Current) (@TA = +25°C, unless otherwise specified.) 80% 82% 84% 86% 88% 90% 92% 94% 96% 98% 100% 6 9 12 15 18 21 24 27 33 INPUT VOLTAGE (V) Figure 13 Efficiency vs. Input Voltage EFFICIENCY 30 36

2 LEDs

3 LEDs

4 LEDs

5 LEDs

6 LEDs7 LEDs 8 LEDs

L = 100µH R = 150m T = 25°C S A Ω

5 LEDs 6 LEDs

8 LEDs

INPUT VOLTAGE (V) Figure 14 330mA LED Current vs. Input Voltage LED CURRENT (A) 0.30 0.31 0.32 0.33 0.34 0.35 0.36 6 9 12 15 18 21 24 27 30 33 36 L = 68 H R = 300m T = 25 C µ S A Ω

7 LEDs

INPUT VOLTAGE (V) Figure 15 Switching Frequency vs. Input Voltage L = 100 H R = 150m T = 25 C µ S A Ω SWITCHING FREQUENCY (kHz) 6 9 12 15 18 21 24 27 30 33 36

3 LEDs 4 LEDs

6 LEDs

INPUT VOLTAGE (V) Figure 16 670mA LED Current vs. Input Voltage LED CURRENT (A) 0.720 30 33 0.710 0.700 0.690 0.680 0.670 0.660 0.650 0.640 0.630 0.620 INPUT VOLTAGE (V) Figure 17 1A LED Current vs. Input Voltage LED CURRENT (A) 0.90 0.95 1.00 1.05 1.10 6 9 12 15 18 21 24 27 30 33 36

Document number: DS43562 Rev. 5 - 3 7 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805 Typical Performance Characteristics (cont.) (1A LED Current) (@TA = +25°C, unless otherwise specified.) INPUT VOLTAGE (V) Figure 18 LED Current Deviation vs. Input Voltage % ERROR 6 9 12 15 18 21 24 27 30 33 36 -1% -2% -3% -4% -5% 0 100 150 200 250 300 350 INPUT VOLTAGE (V) Figure 19 Switching Frequency vs. Input Voltage FREQUENCY (kHz) L = 100 H R = 150m T = 25 C µ S A Ω 6 9 12 15 18 21 24 27 30 33 36 INPUT VOLTAGE (V) Figure 20 LED Current Deviation vs. Input Voltage -10% -8% -6% -4% -2% 10%% ERROR 6 9 12 15 18 21 24 27 30 33 36 0 100 150 200 250 300 350 400 450 500 INPUT VOLTAGE (V) Figure 21 Switching Frequency vs. Input Voltage SWITCHING FREQUENCY (kHz) 6 9 12 15 18 21 24 27 30 33 36 -10% -8% -6% -4% -2% 10% INPUT VOLTAGE (V) Figure 22 LED Current Deviation vs. Input Voltage % ERROR 6 9 12 15 18 21 24 27 30 33 36 INPUT VOLTAGE (V) Figure 23 Switching Frequency vs. Input Voltage 100 200 300 400 500 600 700 800FREQUENCY (kHz) 6 9 12 15 18 21 24 27 30 33 36 900

Document number: DS43562 Rev. 5 - 3 8 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805

Application Information

3 LEDs 5 LEDs

6 LEDs 7 LEDs

-8% -6% -4% -2% 10% INPUT VOLTAGE (V) Figure 24 LED Current Deviation vs. Input Voltage L = 100 H R = 100m T = 25 C µ S A Ω % ERROR -10% 6 9 12 15 18 21 24 27 30 33 36 INPUT VOLTAGE (V) Figure 25 Switching Frequency vs. Input Voltage SWITCHING FREQUENCY (kHz) 9 12 15 18 21 24 27 30 33 366 -8% -6% -4% -2% 10% INPUT VOLTAGE (V) Figure 26 LED Current Deviation vs. Input Voltage L =68 H R = 100m T = 25 C µ S A Ω % ERROR 6 9 12 15 18 21 24 27 30 33 36

4 LEDs5 LEDs

2 LEDs3 LEDs

4 LEDs 6 LEDs7 LEDs

L = 68 H R = 100m T = 25 C µ S A Ω INPUT VOLTAGE (V) Figure 27 Switching Frequency vs. Input Voltage 6 9 12 15 18 21 24 27 30 33 36 SWITCHING FREQUENCY (kHz) -8% -6% -4% -2% 10% INPUT VOLTAGE (V) Figure 28 LED Current Deviation vs. Input Voltage L = 33 H R = 100m T = 25 C µ S A Ω % ERROR -10% 6 9 12 15 18 21 24 27 30 33 36 INPUT VOLTAGE (V) Figure 29 Switching Frequency vs. Input Voltage 700SWITCHING FREQUENCY (kHz) 6 9 12 15 18 21 24 27 30 33 36

Document number: DS43562 Rev. 5 - 3 9 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805 AL8805 Operation In normal operation, when voltage is applied at +V IN, the AL8805 internal switch is turned on. Current starts to flow through sense resistor R 1, inductor L1, and the LEDs. The current ramps up linearly, and the ramp rate is determined by the input voltage +Vin and the inductor L1. This rising current produces a voltage ramp across R1. The internal circuit of the AL8805 senses the voltage across R1 and applies a proportional voltage to the input of the internal comparator. When this voltage reaches an internally set upper threshold, the internal switch is turned off. The inductor current continue s to flow through R 1, L1, the LEDs and the schottky diode D1, and back to the supply rail, but it decays, with the rate of decay determined by the forward voltage drop of the LEDs and the schottky diode. This decaying current produces a falling voltage at R 1, which is sensed by the AL8805. A voltage proportional to the sense voltage across R 1 is applied at the input of the internal comparator. When this voltage falls to the internally set lower threshold, the internal switch is turned on again. This switch-on-and-off cycle continues to provide the average LED current set by the sense resistor R1. LED Current Control The LED current is controlled by the resistor R1 in Figure 30. Connected between VIN and SET the nominal average output current in the LED(s) is defined as: SET THD LED R VI = If the CTRL pin is driven by an external voltage (higher than 0.4V and lower than 2.5V), the average LED current is: SET THD REF CTRL LED R V V VI = For example for a desired LED current of 660mA and a default voltage VCTRL=2.5V the resulting resistor is: Ω≈== m1505.2 5.2 66.0 1.0 V V I VR REF CTRL LED THD SET Figure 30 Typical Application Circuit DC Dimming The CTRL pin can be driven by an external DC voltage (V CTRL), to adjust the output current to a value below the nominal average value defined by RSET. The LED current decreases linearly with the CTRL voltage when 0.5V ≤ VCTRL ≤ 2.5V, as in Figure 2 for 4 different current levels. When the CTRL voltage falls below the threshold, 0.4V, the output switch is turned off which allows PWM dimming. Note that 100% brightness setting corresponds to VCTRL = VREF, nominally 2.5V. For any voltage applied on the CTRL pin that is higher than VREF, the device will not overdrive the LED current and will still set the current according to the equation VCTRL = VREF. Application Information (cont.) AL8805 VIN SET SW CTRL GND

Document number: DS43562 Rev. 5 - 3 11 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805 Soft Start The AL8805 does not have in- built soft-start action – this provides very fast turn off of the output the stage improving PWM dimming accuracy; nonetheless, adding an external capacitor from the CTRL pin to ground will provide a soft -start delay. This is ac hieved by increasing the time taken for the CTRL voltage 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 a capacitor increases the time taken for the output to reach 90% of its final value, this delay is 0.1ms/nF, but will impact on the PWM dimming accuracy depending on the delay introduced. Figure 33 Soft Start with 22nF Capacitor on CTRL Pin (VIN = 36V, ILED = 667mA, 1 LED) Reducing Output Ripple Peak to peak ripple current in the LED(s) can be reduced, if required, by shunting a capacitor C2 across the LED(s) as shown already in the circuit schematic. A value of 1μF will reduce the supply ripple current by a factor three (approx.). Proportionally lower ripple can be achieved with higher capacitor values. Note that the capacitor will not affect operating frequency or efficiency, but it will increase start -up delay, by reducing 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 without altering the mean current value. Capacitor Selection The small size of ceramic capacitors makes them ideal for AL8805 applications. X5R and X7R types are recommended because they retain their capacitance over wider voltage and temperature ranges than other types such as Z5U. A 2.2μF input capacitor is sufficient for most intended applications of AL8805; however a 4.7μF input capacitor is suggested for input voltages approaching 36V. Application Information (cont.)

Document number: DS43562 Rev. 5 - 3 14 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805 Figure 37 Top Layer Figure 38 Bottom Layer Table1 MR16 Application Example Bill of Material Quantity PCB Ident Value Description Suggested Sources

1 U1 AL8805 LED Driver IC Diodes Zetex

1 D1, DFLS240L freewheeling diode Diodes Zetex

4 D2, D3, D4, D5 SBR2A40 Input bridge Diodes Zetex

1 R1 0R15 Resistor, 0805, +/-1% <+/-300ppm Generic

1 C1 150uF 20V SMD tantalum Kemet D case, T491X157K020AT Kemet

0 C2 - Not fitted

1 C3 100nF > = 25V X7R 0805 Generic Kemet C0805C104K5RAC (50v)

NIC NMC0805X7R104K50TRPF (50v) Kemet NIC Components

1 C4 1uF > = 25V X7R 1206 Generic Kemet C1206105K5RAC7800 (50v)

NIC NMC1206X7R105K50F (50v) Kemet NIC Components

1 L1 33µH LPS6235 - 333MLB Coilcraft

Ordering Information

Document number: DS43562 Rev. 5 - 3 15 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805 AL 8805 W5 - 7 Package Packing W5 :SOT25 7 : Tape & Reel Device Package Code Packaging (Note 6) 7” Tape and Reel Quantity Part Number Suffix AL8805W5-7 W5 SOT25 3000/Tape & Reel -7 Note: 8. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at : http://www.diodes.com/datasheets/ap02001.pdf . Marking Information 1 2 3 XX Y W X (Top View) XX : Identification code W : Week : A~Z : 1~26 week; X : A~Z : Internal code Y : Year 0~9 a~z : 27~52 week; z represents 52 and 53 week Part Number Package Identification Code AL8805W5-7 SOT25 A6 Package Outline Dimensions (All dimensions in mm.) Suggested Pad Layout SOT25 Dim Min Max Typ A 0.35 0.50 0.38 B 1.50 1.70 1.60 C 2.70 3.00 2.80 D   0.95 H 2.90 3.10 3.00 J 0.013 0.10 0.05 K 1.00 1.30 1.10 L 0.35 0.55 0.40 M 0.10 0.20 0.15 N 0.70 0.80 0.75 α 0° 8°  All Dimensions in mm A M J LD B C H K N

Document number: DS43562 Rev. 5 - 3 16 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805 Dimensions Value (in mm) Z 3.20 G 1.60 X 0.55 Y 0.80 C1 2.40 C2 0.95 X Z Y C2C2 G

Document number: DS43562 Rev. 5 - 3 17 of 17 www.diodes.com March 2021 © Diodes Incorporated AL8805 IMPORTANT NOTICE 1. DIODES INCORPORATED AND ITS SUBSIDIARIES (“DIODES”) MAKE NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO ANY INFORMATION CONTAINED IN THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTIC ULAR PURPOSE OR NON- INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY RIGHTS (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 2. The Information contained herein is for informational purpose only and is provided only to illustrate the operati on of Diodes products described herein and application examples. Diodes does not assume any liability arising out of the application or use of this document or any product described herein. This document is intended for skilled and technically trained engi neering customers and users who design with Diodes products. Diodes products may be used to facilitate safety -related applications; however, in all instances customers and users are responsible for (a) selecting the appropriate Diodes products for their applications, (b) evaluating the suitability of the Diodes products for their intended applications, (c) ensuring their applications, which incorporate Diodes products, comply the applicable legal and regulatory requirements as well as safety and functional -safety related standards, and (d) ensuring they design with appropriate safeguards (including testing, validation, quality control techniques, redundancy, malfunction prevention, and appropriate treatment for aging degradation) to minimize the risk s associated with their applications. 3. Diodes assumes no liability for any application- related information, support, assistance or feedback that may be provided by Diodes from time to time. 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