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AL8805
HIGH EFFICIENCY 30V 1A BUCK LED DRIVER
Description
The AL8805 is a step-down DC/DC converter designed to drive LEDs with a constant current. The device can drive up to 8 LEDs, depending on the forward voltage of the LEDs, in series from a voltage source of 6V to 30V. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The AL8805 switches at frequency up to 1MHz. This allows the use of small size external components, hence minimizing the PCB area needed. Maximum output current of AL8805 is set via an external resistor connected between the VIN and SET input pins. Dimming is achieved by applying either a DC voltage or a PWM signal at the CTRL input pin. An input voltage of 0.4V or lower at CTRL switches off the output MOSFET simplifying PWM dimming.
Pin Assignments
(Top View)
SW GND CTRL 1 2 3 4 SET 5 VIN
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SOT25
Features
* * * * * * * * LED driving current up to 1A Better than 5% accuracy High efficiency up to 98% Operating input voltage from 6V to 30V 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 (Note 1)
Notes:
Applications
* * MR16 lamps General illumination lamps
1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at http://www.diodes.com/products/lead_free.html.
Typical Application Circuit
AL8805
Document number: DS35030 Rev. 1 - 2
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AL8805
HIGH EFFICIENCY 30V 1A BUCK LED DRIVER
Absolute Maximum Ratings
Symbol ESD HBM ESD MM VIN VSW VCTRL ISW TJ TLEAD TST Parameter Human Body Model ESD Protection Machine Model ESD Protection Continuous VIN pin voltage relative to GND SW voltage relative to GND CTRL pin input voltage Switch current Junction Temperature Lead Temperature Soldering Storage Temperature Range Ratings 2.5 200 -0.3~36 -0.3~36 -0.3 ~ 6 1.25 150 300 -65 to +150 Unit kV V V V V A C C C
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Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be exceeded under any condition. 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
Symbol VIN VCTRLH VCTRLDC VCTRLL ISW TJ Parameter Operating Input Voltage relative to GND Voltage High for PWM dimming relative to GND Voltage range for 20% to 100% DC dimming relative to GND Voltage Low for PWM dimming relative to GND Continuous switch current Junction Temperature Range Min 6.0 2.6 0.5 0 -40 Max 30 5.5 2.5 0.4 1 125 Unit V V V V A C
Pin Descriptions
Pin Name SW GND Pin Number 1 2 Descriptions Switch Pin. Connect inductor/freewheeling diode here, minimizing track length at this pin to reduce EMI. GND Pin 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. Set Nominal Output Current Pin. Configure the output current of the device. Input Supply Pin. Must be locally decoupled to GND with > 2.2F X7R ceramic capacitor - see applications section for more information.
CTRL
3
SET VIN
4 5
AL8805
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AL8805
HIGH EFFICIENCY 30V 1A BUCK LED DRIVER
Electrical Characteristics
VIN =12V, TA=25oC, unless otherwise specified. Symbol Parameter VINSU Internal regulator start up threshold Internal regulator hysteresis VINSH threshold IQ Quiescent current IS Input supply Current VTH Set current Threshold Voltage VTH-H Set threshold hysteresis ISET SET pin input current RCTRL CTRL pin input resistance VREF Internal Reference Voltage RDS(on) On Resistance of SW MOSFET ISW_Leakage Switch leakage current fOSC Switching Frequency Thermal Resistance Junction-toJA Ambient
Notes: 2. 3.
Conditions VIN rising VIN falling Output not switching CTRL pin floating f = 250kHz
Min
Typ.
Max 5.9 300 350 5 105 22
Unit V mV A mA mV mV A k V A MHz C/W
100
95 VSET = VIN-0.1 Referred to internal reference ISW = 1A VIN =30V SOT25 (Note 3)
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1.8 100 20 16 50 2.5 0.25
0.4 0.5 1
250
Refer to figure 34 for the device derating curve. 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. AL8805 does not have a low power standby mode but current consumption is reduced when output switch is inhibited: VSENSE = 0V. Parameter is tested with VCTRL 2.5V
AL8805
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AL8805
HIGH EFFICIENCY 30V 1A BUCK LED DRIVER
Typical Performance Characteristics (TA = 25C unless otherwise stated)
400 350
900 800 700 Frequency (kHz) 600 500 400 300 200
L=33H
300 250 IIN (A) 200 150 VCTRL = 0V VSET = VIN TA = 25C
VIN = 12V 1 LED RSET = 150m TA = 25C
L=68H
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100 50 0 0 5 10 15 VIN (V) 20 25 30
L=100H 100 0 0 1 2 VCTRL 3 4 5
Figure 1 Supply current (not switching) vs Input voltage
1 0.9 0.8 0.7 ILED (A) 0.6 0.5 0.4 0.3 0.2 0.1 0 0 1 2 VCTRL (V) 3 4 5
-40 -60 80
Figure 2. switching frequency vs VCTRL
VIN = 12V 1 LED L = 68H TA = 25C
RSET = 100m
60 40 ICTRL (A) 20 0 -20
VSET = VIN = 12V TA = 25C
RSET = 150m
RSET = 300m
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 VCTRL (V)
Figure 3. LED current vs VCTRL
3
Figure 4. ICTRL vs VCTRL
2.52
2.5
VCTRL = Open VSET = VIN = 12V 2.51
VCTRL = Open VSET = VIN TA = 25C
2 VCTRL (V)
1.5
VCTRL (V)
30
2.50
1
0.5
2.49
0 0 5 10 15 VIN (V) 20 25
2.48 -40 -15 10 35 60 Ambient Temperature (C) 85 110
Figure 5. VCTRL vs Input voltage (CTRL pin open circuit)
F
igure 6. VCTRL vs temperature
AL8805
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HIGH EFFICIENCY 30V 1A BUCK LED DRIVER
Typical Performance Characteristics Continued (TA = 25C unless otherwise stated)
5.0 4.5 4.0 1
300 250 200 150 100 50 0 0 5 10 15 VIN (V) 20 25 30 VCTRL = Open VSET = VIN TA = 25C
LED Current Error (%)
3.0 2.5 2.0 1.5 1.0 0.5 0.0 0% 20% 40% 60% PWM Duty Cycle 80%
0.6 0.5
LED Current Error
ILED
0.4 0.3 0.2 0.1 0 100%
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Figure 7. ILED vs PWM duty cycle
400 350 300 250 200 150 100 -40 -15 10 35 60 Ambient Temperature (C) 85 110 VCTRL = Open VSET = VIN = 12V
LED Current (A)
RDS(ON) (m)
3.5
VIN = 12V 1LED RSET = 150m L = 68H
0.9 0.8 0.7
Figure 8. SW RDS(ON) vs input voltage
130 125 120 115 VSENSE (mV) 110 105 100 95 90 85 80 0 2 RSET = 150m L = 68H VIN = 12V 1LED Load 4 Time (s) 6 8 VSENSE VSW 18 16 14 12 10 8 6 4 2 0 -2 VSW
RDS(ON) (m)
F
100% 90% 80% 70% Duty Cycle 60% 50% 40% 30% 20% 10% 0% 6 9 12
igure 9. SW RDS(ON) vs temperature
RSET = 150m, L = 68H, VIN = 12V, 1 LED Load, TA = 25C 1 20 Duty Cycle = 5% 0.9 18 0.8 LED Current (A) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0 50 100 Time (s) 150 VCTRL ILED VSW 16 14 12 10 8 6 4 2 0 200 Switch and CTRL voltage (V) .
Figure 10. SW Output switching characteristics
L = 33H RS = 150m TA = 25C 2 LED
15 18 21 Input voltage (V)
24
27
30
Figure 11. PWM dimming
Figure 12. Duty cycle vs Input voltage
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HIGH EFFICIENCY 30V 1A BUCK LED DRIVER
Typical Performance Characteristics Continued (TA = 25C unless otherwise stated)
0.39
100% 98% 96% 3 LEDs 2 LEDs 94% Efficiency 92% 90% 88% 86% 84% 82% 80% 6 9 12 15 18 21 Input voltage (V) 24 27 30 1 LED L = 100H RS = 150m TA = 25C 6 LEDs 5 LEDs 4 LEDs 7 LEDs 8 LEDs
0.37
0.35 LED Current (A)
2 LEDs 3 LEDs 4 LEDs
0.33
1 LED 5 LEDs 6 LEDs 7 LEDs 8 LEDs
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0.31 L = 68H RS = 300m TA = 25C
0.29
0.27 6 9 12 15 18 21 Input voltage (V) 24 27 30
Figure 13. Efficiency vs Input voltage
800 700 600 500 400 7 LEDs 300 1 LED 200 100 2 LEDs 0 6 9 12 15 18 21 Input voltage (V) 24 27 30 3 LEDs 4 LEDs 5 LEDs 6 LEDs 8 LEDs L = 68H RS = 300m TA = 25C
Figure 14. 330mA LED current vs Input voltage
0.8
0.75
Switching frequency (kHz)
LED Current (A)
0.7
2 LEDs 1 LED
3 LEDs 4 LEDs
5 LEDs
6 LEDs 7 LEDs 8 LEDs
0.65 L = 68H RS = 150m TA = 25C
0.6
0.55 6 9 12 15 18 21 Input voltage (V) 24 27 30
Figure 15. Switching frequency vs Input voltage
1.20 1.15 1.10 LED current (A) 1.05 1.00 1 LED 0.95 0.90 0.85 0.80 6 9 12 15 18 21 Input voltage (V) 24 27 30 L = 68H RS = 100m TA = 25C 3 LEDs
Figure 16. 670mA LED current vs Input voltage
2 LEDs
4 LEDs
5 LEDs
6 LEDs 7 LEDs
8 LEDs
Figure 17. 1A LED current vs input voltage
AL8805
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AL8805
HIGH EFFICIENCY 30V 1A BUCK LED DRIVER
Typical Performance Characteristics (670mA LED current) (TA = 25C unless otherwise stated)
10% 8%
300 350 L = 100H RS = 150m TA = 25C
6% 4% % Error 2% 0% -2% 1 LED 2 LEDs 3 LEDs 4 LEDs 5 LEDs 6 LEDs 8 LEDs 7 LEDs
Freq (kHz) 250
200
150
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-4% -6% -8%
L = 100H RS = 150m TA = 25C
100 1 LED 50 2 LEDs 3 LEDs 4 LEDs 5 LEDs 24 7 LEDs 6 LEDs 8 LEDs
-10% 6 9 12 15 18 21 Input voltage (V) 24 27 30
0 6 9 12 15 18 21 Input voltage (V) 27 30
Figure 18: LED current deviation vs Input voltage
10% 8% 6% 4% 2% % Error 0% -2% -4% -6% -8% -10% 6 9 12 15 18 21 Input voltage (V) 24 27 30 L = 68H RS = 150m TA = 25C 1 LED 2 LEDs 3 LEDs 4 LEDs 5 LEDs 6 LEDs 7 LEDs 8 LEDs
Figure 19: Switching frequency vs Input voltage
500 450 400 Switching frequency (kHz) 350 300 250 200 150 1 LED 100 50 2 LEDs 3 LEDs 4 LEDs 0 6 9 12 15 18 21 Input voltage (V) 24 27 30 6 LEDs 5 LEDs 7 LEDs 8 LEDs L = 68H RS = 150m TA = 25C
Figure 20: LED current deviation vs Input voltage
10% 8% 6% 4% 2 LEDs 3 LEDs 2% % Error 0% -2% -4% -6% -8% -10% 6 9 12 15 18 21 Input voltage (V) 24 27 30
100 800 700 600 500
Figure 21: Switching frequency vs Input voltage
L = 33H RS = 150m TA = 25C
4 LEDs
5 LEDs 6 LEDs 7 LEDs 8 LEDs
Freq (kHz)
400 300 1 LED 200 6 LEDs 3 LEDs 9 12 4 LEDs 5 LEDs 15 18 21 Input voltage (V) 24 27 30 7 LEDs 8 LEDs
1 LED L = 33H RS = 150m TA = 25C
2 LEDs 0 6
Figure 22: LED current deviation vs Input voltage
Figure 23: Switching frequency vs Input voltage
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AL8805
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AL8805
HIGH EFFICIENCY 30V 1A BUCK LED DRIVER
Typical Performance Characteristics (1A LED current) (TA = 25C unless otherwise stated)
10%
250
8% 6% 2 LEDs 4% 2% % Error 1 LED 0% -2% 3 LEDs 4 LEDs 5 LEDs
Switching frequency (kHz) 200
L = 100H RS = 100m TA = 25C
6 LEDs
7 LEDs 8 LEDs
150
100 1 LED 50 5 LEDs 6 LEDs 7 LEDs 8 LEDs
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-4% -6% -8%
L = 100H RS = 100m TA = 25C
2 LEDs
3 LEDs 9 12
4 LEDs 15
-10% 6 9 12 15 18 21 Input voltage (V) 24 27 30
0 6 18 21 Input voltage (V) 24 27 30
Figure 24: LED current deviation vs Input voltage
10% 8% 6% 4% 2% % Error 0% -2% -4% -6%
50 300 350
Figure 25: Switching frequency vs Input voltage
2 LEDs
3 LEDs 4 LEDs 5 LEDs
6 LEDs 7 LEDs 8 LEDs
Switching frequency (kHz) 250
L = 68H RS = 100m TA = 25C
200
1 LED L = 68H RS = 100m TA = 25C
150
100
1 LED 8 LEDs
-8%
2 LEDs 4 LEDs 5 LEDs 3 LEDs 12
6 LEDs 7 LEDs
-10% 6 9 12 15 18 21 Input voltage (V) 24 27 30
0 6 9 15 18 21 Input voltage (V) 24 27 30
Figure 26: LED current deviation vs Input voltage
10% 8% 6% 4% 2% % Error 0% -2% -4% -6% -8% -10% 6 9 12 15 18 21 Input voltage (V) 24 27 30
0 500 600
Figure 27: Switching frequency vs Input voltage
L = 33H RS = 100m TA = 25C
2 LEDs
5 LEDs 6 LEDs
7 LEDs 8 LEDs
Switching frequency (kHz)
3 LEDs
4 LEDs
400
1 LED
300
200
1 LED
L = 33H RS = 100m TA = 25C
100 2 LEDs 6 9 3 LEDs 4 LEDs 12 5 LEDs 6 LEDs
7 LEDs
8 LEDs
15 18 21 Input voltage (V)
24
27
30
Figure 28: LED current deviation vs Input voltage
Figure 29: Switching frequency vs Input voltage
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AL8805
HIGH EFFICIENCY 30V 1A BUCK LED DRIVER Applications Information
AL8805 Operation
In normal operation, when voltage is applied at +VIN, the AL8805 internal switch is turned on. Current starts to flow through sense resistor R1, 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 continues to flow through R1, 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 R1, which is sensed by the AL8805. A voltage proportional to the sense voltage across R1 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.
VIN CTRL
SET
1
R1
D1 C1
AL8805
C2
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GND SW
L1
Figure 30: Typical Application Curcuit
DC Dimming
The CTRL pin can be driven by an external DC voltage (VCTRL), 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.
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: ILED = VTHD RSET
If the CTRL pin is driven by an external voltage (higher than 0.4V and lower than 2.5V), the average LED current is:
PWM Dimming
LED current can be adjusted digitally, by applying a low frequency Pulse Width Modulated (PWM) logic signal to the CTRL pin to turn the device on and off. This will produce an average output current proportional to the duty cycle of the control signal. In particular, a PWM signal with a max resolution of 10bit can be applied to the CTRL pin to change the output current to a value below the nominal average value set by resistor RSET. To achieve this resolution the PWM frequency has to be lower than 500Hz, however higher dimming frequencies can be used, at the expense of dimming dynamic range and accuracy.
ILED =
VCTRL VTHD VREF R SET
For example for a desired LED current of 660mA and a default voltage VCTRL=2.5V the resulting resistor is: R SET = VTHD VCTRL 0 .1 2 .5 = 150m ILED VREF 0.66 2.5
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Applications Information (cont.)
PWM Dimming (cont.)
Typically, for a PWM frequency of 500Hz the accuracy is better than 1% for PWM ranging from 1% to 100%.
700 600
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LED current [mA]
500 400 300 200 100 0
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
PWM dimming [%]
Figure 30. PWM Dimming at 500Hz
70 60
LED current [mA]
50 40 30 20 10 0
0%
1%
2%
3%
4%
5%
6%
7%
8%
9%
10%
PWM dimming [%]
Figure 31. Low duty cycle PWM Dimming at 500Hz
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HIGH EFFICIENCY 30V 1A BUCK LED DRIVER Applications Information (cont.)
PWM Dimming (cont.)
The PWM pin is designed to be driven by both 3.3V and 5V logic levels directly from a logic output with either an open drain output or push-pull output stage.
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 softstart 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. 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.
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\
Figure 32. Soft start with 22nF capacitor on CTRL pin (VIN = 30V, ILED = 667mA, 1 LED)
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HIGH EFFICIENCY 30V 1A BUCK LED DRIVER
Applications Information (cont.)
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 1F 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. where TJ(MAX) is the maximum operating junction temperature, TA is the ambient temperature, and JA is the junction to ambient thermal resistance. The recommended maximum operating junction temperature, TJ, is 125C and so maximum ambient temperature is determined by the AL8805's junction to ambient thermal resistance, JA. JA, is layout dependent and the AL8805's JA on a 25x25mm single layer PCB with 1oz copper standing in still air is approximately 250C/W (160C/W on a four-layer PCB). The maximum power dissipation at TA = 25C can be calculated by the following formulas: PD(MAX) = (125C - 25C) / (250C/W) = 0.4W for singlelayer PCB PD(MAX) = (125C - 25C) / (160C/W) = 0.625W for standard four-layer PCB Figure 34, shows the power derating of the AL8805 on two (one single-layer and four-layer) different 25x25mm PCB with 1oz copper standing in still air.
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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 2.2F input capacitor is sufficient for most intended applications of AL8805; however a 4.7F input capacitor is suggested for input voltages approaching 30V.
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. The Schottky diode also provides better efficiency than silicon PN 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. In particular, it is recommended to have a diode voltage rating at least 15% higher than the operating voltage to ensure safe operation during the switching and a current rating at least 10% higher than the average diode current. The power rating is verified by calculating the power loss through the diode. Schottky diodes, e.g. B240 or B140, with their low forward voltage drop and fast reverse recovery, are the ideal choice for AL8805 applications.
Figure 34. Derating Curve for different PCB
Thermal and layout considerations
For continuous conduction mode of operation, the absolute maximum junction temperature must not be exceeded. The maximum power dissipation depends on several factors: the thermal resistance of the IC package JA, PCB layout, airflow surrounding the IC, and difference between junction and ambient temperature. The maximum power dissipation can be calculated using the following formula:
Figure 35 gives details about the PCB layout suggestions: 1. the capacitor C1 has to be placed as close as possible to VIN 2. The sense resistor R1 has to be placed as close as possible to VIN and SET 3. The D1 anode, the SW pin and the inductor have to be placed as close as possible to avoid ringing.
PD(MAX) = (TJ(MAX) - TA) / JA
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Applications Information (cont.)
The AL8805 guarantee high level of performance both with 12VAC and 12VDC power supply. 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. In table 1 can be found the bill of material of the MR16 application example.
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In figures 37 and 38 are displayed the top layer and the bottom layer of a typical PCB design for an MR16 solution.
Figure 35. Recommended PCB Layout
Application Example
Typical application example for the AL8805 is the MR16 lamp. They typically operate from 12VDC or 12VAC, using conventional electromagnetic transformers or electronic transformers. As a replacement in some halogen lamp applications LEDs offer a more energy efficient solution - providing no radiated heat and no Ultra Violet light. This application example is intended to fit into the base connector space of an MR16 style LED lamp. The design has been optimized for part count and thermal performance for a single 3W LED in the Lens section.
Figure 37. Top Layer
AL8805
Figure 36. MR16 Schematic
An inductor choice of 33H with saturation current higher than 1.1A, will limit the frequency variation between 230kHz and 350kHz over the whole input voltage variation (8V to 18V), and therefore represent the best choice for an MR16 solution also taking into account the size constraint of the lamp.
Figure 38. Bottom Layer
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Application Information (cont.)
Table 1. MR16 application example Bill of Material QUANTITY PCB IDENT VALUE DESCRIPTION SUGGESTED SOURCES Diodes Zetex Diodes Zetex Diodes Zetex
1 1 4 1 1
U1 D1, D2, D3, D4, D5 R1 C1 C2 C3 C4 L1
AL8805 DFLS240L SBR2A40 0R15 150uF 20V 100nF >=25V 1uF >=25V 33H
LED Driver IC freewheeling diode Input bridge Resistor, 0805, +/-1% <+/-300ppm Generic KOA SR732ATTDR150F SMD tantalum Kemet D case, T491X157K020AT Not fitted X7R 0805 Generic Kemet C0805C104K5RAC (50v) NIC NMC0805X7R104K50TRPF (50v)
Kemet Kemet
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0 1 1 1
Kemet NIC Components
X7R 1206 Generic Kemet C1206105K5RAC7800 (50v) Kemet NIC NMC1206X7R105K50F (50v) NIC Components LPS6235 - 333MLB Coilcraft
AL8805
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HIGH EFFICIENCY 30V 1A BUCK LED DRIVER
Ordering Information
AL 8805 W5 - 7
Package
W5 :SOT25
Device Package Code W5 Packaging (Note 4) SOT25
Packing
7 : Tape & Reel
7" Tape and Reel Quantity Part Number Suffix 3000/Tape & Reel -7
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AL8805W5-7
Notes:
4. 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) SOT25
(Top View)
5
4
7
XX Y W X 1 2 3
XX : Identification code Y : Year 0~9 W : Week : A~Z : 1~26 week; a~z : 27~52 week; z represents 52 and 53 week X : A~Z : Internal code
Package SOT25 Identification Code A6
Part Number AL8805W5-7
Package Outline Dimensions (All Dimensions in mm)
(1) Package Type: SOT25
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AL8805
HIGH EFFICIENCY 30V 1A BUCK LED DRIVER
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 make modifications, enhancements, improvements, corrections or other 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 herein; neither does Diodes Incorporated 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 Incorporated 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 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. Product names and markings noted herein may also be covered by one or more United States, international or foreign trademarks. LIFE SUPPORT Diodes Incorporated products are specifically not authorized for use as critical components 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 properly used in accordance with instructions 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.
NEW PRODUCT
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 their products and any use of Diodes Incorporated products in such safety-critical, 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 Incorporated 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 (c) 2010, Diodes Incorporated www.diodes.com
AL8805
Document number: DS35030 Rev. 1 - 2
16 of 16 www.diodes.com
September 2010
(c) Diodes Incorporated

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