October 2011

AL9910-EV8 (10/27/2011)

Page 4 of 14

2. EVALUATION BOARD INFORMATION

2.1

AL9910 Pin Assignment and Description

AL9910 Pin Assignment

SO-8

1

2

3

4

5

6

7

8

(Top View)

CS

Gate

GND

LD

Rosc

PWM_D

AL9910

AL9910 Pin Description

Pin Name

Pin Number

Description

1

Input voltage

CS

2

Senses LED string current

GND

3

Device ground

Gate

4

Drives the gate of the external MOSFET

PWM_D

5

Low Frequency PWM Dimming pin, also Enable input. Internal 100kΩ pull-down to

GND

6

Internally regulated supply voltage. 7.5V nominal for AL9910. Can supply up to 1 mA

for external circuitry. A sufficient storage capacitor is used to provide storage when

the rectified AC input is near the zero crossings

LD

7

Linear Dimming by changing the current limit threshold at current sense comparator

8

Oscillator control. A resistor connected between this pin and ground sets the PWM

frequency.