CAT3604V
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9
Table 6. PIN DESCRIPTION
Pin # Name Function
1 EN Device enable (active high).
2 NC Not connected inside the package.
3 NC Not connected inside the package.
4 NC Not connected inside the package.
5 RSET Connect resistor RSET to set the LED current.
6 VOUT Charge pump output connected to the LED anodes.
7 VIN Charge pump input, connect to battery or supply.
8 C1+ Bucket capacitor 1 Positive terminal
9 C1− Bucket capacitor 1 Negative terminal
10 C2− Bucket capacitor 2 Negative terminal
11 C2+ Bucket capacitor 2 Positive terminal
12 GND Ground Reference
13 LED4 LED4 cathode terminal.
14 LED3 LED3 cathode terminal.
15 LED2 LED2 cathode terminal.
16 LED1 LED1 cathode terminal.
TAB GND Connect to GND on the PCB.
Pin Function
VIN is the supply pin for the charge pump. A small 1 mF
ceramic bypass capacitor is required between the VIN pin
and ground near the device. The operating input voltage
range is from 2.5 V to 5.5 V. Whenever the input supply falls
below the under−voltage threshold (1.8 V), all the LED
channels are disabled and the device enters shutdown mode.
EN is the enable input and the high resolution PWM
dimming control. Levels of logic high and logic low are set
at 1.3 V and 0.4 V respectively. When EN is initially taken
high, the device becomes enabled and all LED currents are
set according to the R
SET
resistor. To place the device into
“zero current” shutdown mode, the EN pin must be held low
for at least 1.5 ms.
VOUT is the charge pump output that is connected to the
LED anodes. A small 1 mF ceramic bypass capacitor is
required between the V
OUT
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 ceramic bucket
capacitor C
1
.
C2+, C2− are connected to each side of the ceramic bucket
capacitor C
2
.
LED1 to LED4 provide the internal regulated current
source for each of the LED cathodes. These pins enter
high−impedance zero current state whenever the device is
placed in shutdown mode. If an LED pin is directly tied to
VOUT, that channel is disabled.
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.
RSET is connected to the resistor (R
SET
) to set the current
for the LEDs. The voltage at this pin regulated to 0.6 V. The
ground side of the external resistor should be star connected
back to the GND of the PCB. In shutdown mode, RSET
becomes high impedance.
