PT6901

V1.5

3

August, 2009

ORDER INFORMATION

Valid Part Number

Package Type

Top Code

PT6901-SA

8 Pins, SOP, 150MIL

PT6901-SA

PIN CONFIGURATION

PIN DESCRIPTION

Pin Name

Description

Pin No.

CS

Senses LED string current with an external sense resistor. When the voltage of CS pin exceeds

the lower of either the internal 240mV or the voltage of LD pin, the GD output goes low.

1

GND

IC Ground.

2

GD

IC output drives the gate of external MOSFET.

3

VIN

Input supply voltage 8V-12V DC.

4

PWMD

Low frequency PWM dimming pin, also enable pin. When PWMD pin is floating or is pulled to

GND, IC operates in shut-down mode. When PWMD pin is pulled to high, IC operates normally.

5

VDD

Internal regulated voltage. The voltage acts as power supply of internal control circuit, also

provides a supply voltage for external circuit. The current source capability is limited less than

10mA.

6

LD

Linear dimming. If the voltage at the LD pin is less than 240mV, the LD pin voltage sets the

current sense threshold.

7

RF

Oscillator frequency control. The PT6901 operates in constant frequency mode when a resistor

is connected between RF and GND. The PT6901 operates in constant off-time mode when a

resistor is connected between RF and GD.

8