AL8807 datasheet(16/21 Pages) DIODES

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AL8807

HIGH EFFICIENCY LOW EMI 36V 1A BUCK LED DRIVER

AL8807

Document number: DS35281 Rev. 4 - 2

16 of 21

www.diodes.com

June 2012

Applications Information (cont.)

The associated EMI measurements for this board using the AL8807 is shown in figure 40.

Fig 40. AL8807EV2 Radiated EMI Performance

The EMI performance was measured at 12VDC driving two white LEDs (VF = 3.1V at 660mA) on the AL8807EV2. The red bold

line is for 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.

MR16 lamps typically operate from 12VDC or 12VAC, using conventional electromagnetic transformers or electronic

transformers.

In enclosed lamps such MR16 the ability for the device to operate at high ambient temperatures is critical and figure 41 shows

the surface temperature of the AL8807 on AL8807EV2 in operation under the same conditions as the EMI tests at an free air

temperature of 25ºC. It is anticipated that the internal junction temperature is approximately 6 ºC hotter than the surface

temperature.

Fig 41. Thermal picture of AL8807EV2 at 12VDC 2 white LEDS at 660mA

The thermal image shows that components increasing the board temperature are the inductor, Schottky diodes and the

AL8807.

AL8807 Datasheet(PDF) 16 Page - Diodes Incorporated