LDS8720

© 2011 IXYS Corp.

5

Doc. No. 8720DS, Rev. N1.1

Characteristics subject to change without notice

PIN DESCRIPTION

Pin #

Name

Function

1

Input Voltage, connect to battery or power supply

2

GND

Analog Ground

3

PGND

Power Ground

4

SW

Switch input; Connect inductor terminal to this pin

5

Output voltage; Connect the LED string anode

terminal to this pin.

6

HVB

High Voltage Bypass; Connect a 470 pF capacitor

7

LEDS

Current Sense input. Connect LED string cathode

terminal to this pin

8

EN/PWM Device Enable (active high) and Dimming Control

PAD

PAD

Connect to GND on the PCB

Top view: TDFN 8-lead 2 X 3 mm

PIN FUNCTION

pin and ground near the device. The operating input

voltage range is from 2.7 V to 5.5 V. If the input

supply

voltage

falls

below

the

under-voltage

threshold, switch is disabled, and the device enters

shutdown mode.

HVB is the internal high voltage reference point.

Connect a 4700 pF capacitor between this point and

EN/PWM is the enable and PWM control logic input.

Guaranteed levels of logic high and logic low are set

at 1.4 V and 0.4 V respectively. When EN/PWM is

initially taken high, the device becomes enabled and

LED current sets to maximum programmed value..

To place the device into shutdown

mode, the

EN/PWM pin must be held low for more than 10 ms.

anode. A ceramic bypass capacitor of 1 µF requires

GND is the ground reference for the analog circuits.

The pin must be connected to the ground plane on

the PCB. Avoid high currents flowing trough traces

connecting this pin with EN/PWM signal source.

PGND is the current return for high current circuits.

The pin must be connected to the ground plane on

the PCB. Connect GND and PGND as close to the

driver as possible.

LEDS is the Current Sense pin that provides internal

regulated current sink for LED string. Connect LED

string cathode to this pin. This pin 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