al8807 Diodes, Inc., al8807 Datasheet
al8807
Available stocks
Related parts for al8807
al8807 Summary of contents
Page 1
... LEDs provides identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The AL8807 switches at frequency up to 1MHz with controlled rise and fall times to reduce EMI. This allows the use of small size external components, hence minimizing the PCB area needed ...
Page 2
... J AL8807 Document Number: DS35281 Rev HIGH EFFICIENCY LOW EMI 30V 1A BUCK LED DRIVER Descriptions = V = 2.5V giving nominal average output current I CTRL REF < 2.5V) to adjust output current from 20% to CTRL OUTnom Parameter Parameter www.diodes.com AL8807 = 0.1/R ) OUTnom S Ratings Unit 2.5 kV 200 V -0.3~36 V -0.3~ ...
Page 3
... Thermal Resistance Junction-to- θ JC case (Note 7) Notes: 2. AL8807 does not have a low power standby mode but current consumption is reduced when output switch is inhibited: V ≤ 2.5V tested with V CTRL 3. Refer to figure 32 for the device derating curve. 4. 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 ...
Page 4
... R = 300mΩ SET -40 -60 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5 CTRL 2.52 2. Open CTRL 2. SET 25°C A 2. www.diodes.com AL8807 V = 12V IN 1 LED R = 150mΩ SET T = 25° CTRL CTRL 12V SET 25° (V) CTRL Fig vs. V ...
Page 5
... Ambient t Temperature (° Fig vs. Tempe DS(O N) Fig Output Rise T AL8807 Document Numbe r: DS35281 Rev HIGH E FFICIENCY Y LOW EM eristics (con nt 25° C unless oth A 1 300 V = 12V IN 0.9 1LED 250 ...
Page 6
... LEDs 2 LEDs 0.70 0.68 1 LED 0.66 0.64 L=68µH 0.62 R =150m S T =25° Fig. 16 670mA LED Current vs. Input Voltage www.diodes.com AL8807 Ω 4 LEDs 5 LEDs 6 LEDs 7 LEDs 8 LEDs INPUT VOLTAGE (V) 8 LEDs 4 LEDs 7 LEDs 6 LEDs 5 LEDs Ω ...
Page 7
... LEDs 7 LEDs 500 400 300 1 LED 200 100 2 LEDs 3 LEDs Fig. 23 Switching Frequency vs. Input Voltage www.diodes.com AL8807 = 25°C unless otherwise stated) A Ω 8 LEDs 5 LEDs 6 LEDs 7 LEDs INPUT VOLTAGE (V) Ω 5 LEDs 6 LEDs 7 LEDs 8 LEDs 18 ...
Page 8
... S T =25°C 500 A 400 300 200 1 LED 100 2 LEDs 3 LEDs 4 LEDs Fig. 29 Switching Frequency vs. Input Voltage www.diodes.com AL8807 5 LEDs 6 LEDs 7 LEDs 8 LEDs INPUT VOLTAGE (V) Ω 5 LEDs 6 LEDs 7 LEDs 8 LEDs INPUT VOLTAGE (V) Ω ...
Page 9
... LED R SET AL8807 Document Numbe r: DS35281 Rev HIGH E FFICIENCY Y LOW the e AL8807 intern nal switch EDs. The curre ent ramps up li nearly, and the p across The internal cir cuit of the AL8 1 of the internal c comparator. et upper thresh ...
Page 10
... Zooming in at duty cycles be low 10% show Fig. The accuracy of the low duty y cycle dimming AL8807. For b est accuracy/re esolution the s reduced. The CTRL pin is designed to be driven by b output or push h pull output sta age. AL8807 Document Numbe r: DS35281 Rev. 3 ...
Page 11
... Soft Start The AL8807 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 achieved 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 ...
Page 12
... P PCB). 5°C can be calc culated by the f following formu C/ single-layer P PCB C/W) = 0.625W W for standard fo our-layer PCB e AL8807W5 o n two (one sin gle-layer and f 807MP FR4 51x51mm PCB with 2oz g. 34 Derating g Curve for D Different PCB ww.diodes.com ...
Page 13
... L Fig Loop Res sonance of the Schottky diode, D1, and d then from inductan ce internally in n the AL8807 th can be used to o estimate the primary resona have a minor effect on the inductance an any oscillation is determined d by the comb e. An exampl ...
Page 14
... The LED current sense resistor (R1) has to be placed as close as possible to the V 5. The majority of the conducted heat from the AL8807 is through the GND pin 2. A maximum earth plane with thermal vias into a second earth plane will minimise self-heating 6. To reduce emissions via long leads on the supply input and LEDs low RF impedance capacitors (C2 and C5) should be used at the point the wires are joined to the PCB A Typical application for the AL8807 is an LED MR16 lamp (schematic shown in Figure 37) ...
Page 15
... EN55022 class B used for domestic equipment including lighting. The bottom magenta line is the noise floor of the test chamber. The middle purple line is the EMI emitted radiation of the AL8807 over 30MHz to 1000MHz. This shows that the AL8807 passes the standard with at least 16dB margin. ...
Page 16
... MR16 solution also taking into account the size constraint of the lamp. The AL8807 guarantees high performance levels with both 12V The efficiency is generally higher than 81% and current regulation is better than 0.1mA/V in for a DC input voltage in the range from 8V to 18V ...
Page 17
... X : A~Z : Inte ernal code ackage Identificat 7 S SOT25 Part Num mber Pac ckage AL8807M MP-13 MSO OP-8EP ww.diodes.com AL L8807 MI 30V 1A B BUCK LED DRIVER 7” Tape a and Reel Qua antity Part Numbe er Suffix ape & ...
Page 18
... α L All Dimensions in mm Dim Min Gauge plane All Dimensions Detail www.diodes.com AL8807 SOT25 Min Max Typ 0.35 0.50 0.38 1.50 1.70 1.60 2.70 3.00 2.80 ⎯ ⎯ 0.95 2.90 3.10 3.00 0.013 0.10 0.05 1.00 1.30 1.10 0.35 0.55 0.40 0.10 0.20 0.15 0.70 0.80 0.75 ⎯ 0° 8° MSOP-8EP Typ Max - 1.10 - 0.05 0.15 0.10 0.75 0.95 0.86 0.22 0.38 0.30 ...
Page 19
... MSOP-8EP AL8807 Document Number: DS35281 Rev HIGH EFFICIENCY LOW EMI 30V 1A BUCK LED DRIVER C2 C2 Dimensions Value (in mm Dimensions Value (in mm www.diodes.com AL8807 3.20 1.60 0.55 0.80 2.40 0.95 4.2 0.65 0.32 1.95 0.8 1.65 November 2011 © Diodes Incorporated ...
Page 20
... Diodes Incorporated products in such safety-critical, life support devices or systems. Copyright © 2011, Diodes Incorporated AL8807 Document Number: DS35281 Rev HIGH EFFICIENCY LOW EMI 30V 1A BUCK LED DRIVER IMPORTANT NOTICE LIFE SUPPORT www.diodes.com www.diodes.com AL8807 November 2011 © Diodes Incorporated ...