LDS8621

© 2009 IXYS Corp.

3

Doc. No. 8621DS, Rev. N1.0

Characteristics subject to change without notice

PIN DESCRIPTION

Pin #

Name

Function

1

NC

No connect

2

LEDA

LED A cathode terminal

3

LEDB

LED B cathode terminal

4 - 6

NC

No connect

7

Charge pump output connected to the LED anodes

8

Charge pump input, connect to battery or supply

9

C1+

Bucket capacitor 1 Positive terminal

10

C1-

Bucket capacitor 1 Negative terminal

11

C2+

Bucket capacitor 2 Positive terminal

12

C2-

Bucket capacitor 2 Negative terminal

13

PWM2

LEDB PWM brightness control

14

PWM1

LEDA PWM brightness control

15, 16

GND

Ground Reference, Connect both pins to GND

Top view: TQFN 16-lead 3 X 3 mm

PAD

PAD

Connect to GND on the PCB

PIN FUNCTION

ceramic bypass capacitor is required between the Vin

pin and ground near the device. The operating input

voltage range is from 2.5V to 5.5V. Whenever the

input supply falls below the under-voltage threshold

(1.8V), all the LED channels are disabled and the

device enters shutdown mode.

ground near the device.

GND is the ground reference for the charge pump.

The pin must be connected to the ground plane on

the PCB.

C1+, C1- are connected to each side of the ceramic

bucket capacitor C1

C2+, C2- are connected to each side of the ceramic

bucket capacitor C2

LEDA and LEDB provide the internal regulated

current source for each of the LED cathodes. These

pins

enter

high-impedance

zero

current

state

whenever the device is in shutdown mode.

PAD is the exposed pad underneath the package.

For best thermal performance, the pad should be

soldered to the PCB and connected to the ground

plane

PWM1, PWM2 are the enable and PWM LED

brightness control logic inputs. Guaranteed levels of

logic high and logic low are set at 1.3 V and 0.4 V

respectively. When any of PWM pins is taken high,

the device becomes enabled with maximum LED

current at associated LED. To place the LDS8621

into zero current mode, both PWM pins must be held

low for more than 30 ms.