CAT3614 Datasheet, PDF (8/12 Pages) Catalyst Semiconductor – 4-Channel 1-Wire LED Driver in 3x3mm Package

CAT3614
PIN DESCRIPTIONS
Pin #
Name
Function
1
VIN
Supply voltage.
2
C1+
Bucket capacitor 1 terminal
3
C1-
Bucket capacitor 1 terminal
4
C2-
Bucket capacitor 2 terminal
5
C2+
Bucket capacitor 2 terminal
6
GND
7
LED1
8
LED2
9
LED3
10
LED4
Ground reference
LED1 cathode terminal (if not used, connect to VOUT)¹
LED2 cathode terminal (if not used, connect to VOUT)¹
LED3 cathode terminal (if not used, connect to VOUT)¹
LED4 cathode terminal (if not used, connect to VOUT)¹
11
EN/DIM
Device enable (active high) and dimming control input
12
VOUT
Charge pump output connected to the LED anodes
TAB
TAB
Connect to GND on the PCB
Note:
(1) LED1, LED2, LED3, LED4 pins should not be left floating. They should be connected to the LED cathode, or tied to VOUT pin if not used.
PIN FUNCTION
VIN is the supply pin for the charge pump. A small
1µF ceramic bypass capacitor is required between
the VIN pin and ground near the device. The
operating input voltage range is from 2.2V to 5.5V.
Whenever the input supply falls below the
undervoltage threshold (2V) all LEDs channels will
be automatically disabled.
EN/DIM is the enable and dimming control logic
input for all LED channels. Guaranteed levels of
logic high and logic low are set at 1.3V and 0.4V
respectively. When EN/DIM is initially taken high, the
device becomes enabled and all LED currents
remain at 0mA. The falling edge of the first pulse
applied to EN/DIM sets all LED currents to their full
scale of 31mA.
On each consecutive falling edge of the pulse
applied to EN/DIM, the LED current is decreased by
1mA step. On the 32nd pulse, the LED current is set
to zero. The next pulse on EN/DIM resets the current
back to their full scale of 31mA.
To place the device into zero current shutdown
mode, the EN/DIM pin must be held low for 1.5ms or
more.
VOUT is the charge pump output that is connected
to the LED anodes. A small 1µF ceramic bypass
capacitor is required between the VOUT pin and
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 1µF
ceramic bucket capacitor C1.
C2+, C2- are connected to each side of the 1µF
ceramic bucket capacitor C2.
LED1 to LED4 provide the internal regulated current
for each of the LED cathodes. These pins enter a
high impedance zero current state whenever the
device is placed in shutdown mode. In applications
using less than four LEDs, all unused channels
should be wired directly to VOUT. This ensures the
channel is automatically disabled dissipating less
than 200µA.
TAB is the exposed pad underneath the package.
For best thermal performance, the tab should be
soldered to the PCB and connected to the ground
plane.
Doc. No. 25095, Rev. 01
8
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice