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

CAT3612
Table 5. 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
GND
Ground reference
6
LED1 LED1 cathode terminal (if not used, connect to VOUT) (Note 3)
7
LED2 LED2 cathode terminal (if not used, connect to VOUT) (Note 3)
8
C2+
Bucket capacitor 2 terminal
9
−
Not connected
10
EN/DIM Device enable (active high) and dimming control input.
11
−
Not connected
12
VOUT Charge pump output connected to the LED anodes.
TAB
TAB
Connect to GND on the PCB.
3. 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 1 mF ceramic
bypass capacitor is required between the VIN pin and
ground near the device. The operating input voltage range is
up to 5.5 V. When the input supply falls below the
undervoltage threshold (2 V), 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 1.3 V and 0.4 V respectively. When EN/DIM
is initially taken high, the device becomes enabled and the
LED currents remain at 0 mA. The falling edge of the first
pulse on EN/DIM sets the LED currents to the full scale
150 mA.
On each consecutive falling edge of the pulse on EN/DIM,
the LED current decreases by 150/31 mA. 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 150 mA.
To place the device into zero current shutdown mode, the
EN/DIM pin must be held low for 1.5 ms or more.
VOUT is the charge pump output that is connected to the
LED anodes. A small 1 mF 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 1 mF ceramic
bucket capacitor C1.
C2+, C2− are connected to each side of the 1 mF 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 0.5 mA.
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.
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