CAT4104 Datasheet, PDF (7/13 Pages) ON Semiconductor – 700 mA Quad Channel Constant Current LED Driver

CAT4104
Table 5. PIN DESCRIPTIONS
Name
Pin
SOIC 8−Lead
LED1
1
LED2
2
LED3
3
LED4
4
GND
5
EN/PWM
6
VIN
7
RSET
8
Pin
TDFN 8−Lead
1
2
3
4
5 and TAB
6
7
8
Function
LED1 cathode terminal
LED2 cathode terminal
LED3 cathode terminal
LED4 cathode terminal
Ground reference
Device enable input and PWM control
Device supply pin
LED current set pin for the LED channels
Pin Function
VIN is the supply pin for the device. A small 0.1 mF ceramic
bypass capacitor is optional for noisy environments.
Whenever the input supply falls below the under−voltage
threshold, all LED channels are automatically disabled.
EN/PWM is the enable and one wire dimming 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/PWM is
initially taken high, the device becomes enabled and all LED
currents are set at a gain of 100 times the current in RSET.
To place the device into zero current shutdown mode, the
EN/PWM pin must be held low for 4 ms typical.
LED1 to LED4 provide individual regulated currents for
each of the LED cathodes. There pins enter a high
impedance zero current state whenver the device is placed
in shutdown mode.
RSET pin is connected to an external resistor to set the LED
channel current. The ground side of the external resistor
should be star connected to the GND of the PCB. The pin
source current mirrors the current to the LED sinks. The
voltage at this pin is regulated to 1.2 V.
GND is the ground reference for the device. The pin must be
connected to the ground plane on the PCB.
TAB (TDFN 8−Lead Only) 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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