CAT3603
2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
7
Doc. No. 5017 Rev. C
PIN DESCRIPTIONS
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
Name
LED1
LED2
LED3
RSET
EN
VOUT
VIN
C1+
C1-
C2-
C2+
GND
TAB
Function
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)
The LED output current is set by the current sourced out of the RSET pin
Device enable (active high)
Charge pump output connected to the LED anodes
Supply voltage
Bucket capacitor 1 terminal
Bucket capacitor 1 terminal
Bucket capacitor 2 terminal
Bucket capacitor 2 terminal
Ground Reference
Connect to GND on the PCB
Note:
(1) LED1, LED2, LED3 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 3.0V to 5.5V.
EN
is the enable control logic input for all LED
channels. Guaranteed levels of logic high and logic
low are set at 1.3V and 0.4V respectively.
RSET
pin is regulated at 1.2V. An external resistor
RSET connected from the RSET pin to GND sets the
LED current.
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 LED3
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 three 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.