cat4109 ON Semiconductor, cat4109 Datasheet - Page 6

• Manufacturer Part Number: cat4109
• Description: 3-channel Constant-current Rgb Led Driver With Individual Pwm Dimming
• Manufacturer: ON Semiconductor

CAT4109
PIN DESCRIPTIONS
PIN FUNCTION
PGND is the power ground reference pin for the
device. This pin must be connected to the GND pin
and to the ground plane on the PCB.
GND is the ground reference pin for the entire device.
This pin must be connected to the ground plane on
the PCB.
PWM1 to PWM3 are the control inputs respectively for
LED1, LED2 and LED3 channels. When PWMx are
low, the associated LED channels are turned off.
When PWMx are high, the corresponding channels
are turned on, assuming the OE input is also high.
PWMx pins can not be left open and must be set to
either to logic high or low.
RSET1 to RSET3 are the LED current set inputs. The
current pulled out of these pins will be mirrored in the
corresponding LED channel with a gain of 400.
Doc. No. MD-5042, Rev. A
RSET3
RSET2
RSET1
PWM3
PWM2
PWM1
PGND
Name
LED3
LED2
LED1
GND
VDD
NC
NC
NC
OE
Pin Number
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
Function
Power Ground.
Ground Reference.
PWM control input for LED3
PWM control input for LED2
PWM control input for LED1
LED current set pin for LED3
LED current set pin for LED2
LED current set pin for LED1
LED channel 3 cathode terminal
LED channel 2 cathode terminal
LED channel 1 cathode terminal
Not connected inside package
Not connected inside package
Not connected inside package
Output Enable input pin
Device Supply pin
6
LED1 to LED3 are the LED current sink inputs. These
pins are connected to the bottom cathodes of the LED
strings. The current sinks bias the LEDs with a current
equal to 400 times the corresponding RSETx pin
current. For the LED sink to operate correctly the
voltage on the LED pin must be above 0.4V. Each
LED channel can withstand voltages up to 25V.
OE is the output enable input. When high, all LED
channels are enabled according to the state of their
corresponding PWMx control inputs. When low, all
LED channels are turned off. This pin can be used to
turn all the LEDs off independently of the state of the
PWMx inputs. If the OE stays low for a duration longer
than T
VDD is the positive supply pin voltage for the entire
device. A small 1µF bypass ceramic capacitor is
recommended between VDD pin and ground near the
device.
PWRDWN
, the device enters shutdown mode.
Characteristics subject to change without notice
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