CAT3612 Datasheet, PDF (8/13 Pages) Catalyst Semiconductor – Programmable 300mA Camera Flash LED Driver

CAT3612
PIN DESCRIPTIONS
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
TAB
Name
VIN
C1+
C1-
C2-
GND
LED1
LED2
C2+
-
EN/DIM
-
VOUT
TAB
Function
Supply voltage.
Bucket capacitor 1 terminal
Bucket capacitor 1 terminal
Bucket capacitor 2 terminal
Ground reference
LED1 cathode terminal (if not used, connect to VOUT)¹.
LED2 cathode terminal (if not used, connect to VOUT)¹.
Bucket capacitor 2 terminal
Not connected
Device enable (active high) and dimming control input.
Not connected
Charge pump output connected to the LED anodes.
Connect to GND on the PCB.
Note 1: LED1, LED2 pins should not be left floating. They should be connected to the LED cathode, or tied to the VOUT pin if not used.
PIN FUNCTION
VIN is the supply pin for the device. A small 1µF
ceramic bypass capacitor is required between the VIN
pin and ground near the device. The operating input
voltage range is up to 5.5V. When the input supply
falls below the undervoltage threshold (2V), all LEDs
channels are 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 the LED currents remain at
0mA. The falling edge of the first pulse on EN/DIM
sets the LED currents to the full scale 150mA.
On each consecutive falling edge of the pulse on
EN/DIM, the LED current decreases by 150/31mA. On
the 32^nd pulse, the LED current is set to zero. The
next pulse on EN/DIM resets the current back to full
scale 150mA.
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, LED2 provide the internal regulated current for
each of the LED cathodes. These pins enter a high
impedance zero current state whenever the device is in
shutdown mode. In applications using only one LED
channel, the unused channel should be tied directly to
VOUT. The disabled channel only draws about 0.5mA.
To place the device into zero current shutdown mode,
the EN/DIM pin must be held low for 1.5ms or more.
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. 5016 Rev. A
8
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice