CAT4101_12 Datasheet, PDF (6/9 Pages) ON Semiconductor – 1 A Constant-Current LED Driver

CAT4101
Table 5. PIN DESCRIPTIONS
Name
Pin
EN/PWM
1
VIN
2
GND
3
RSET
4
LED
5
TAB
–
Function
Device enable (active high) and PWM control.
Device supply input, connect to battery or supply.
Ground reference.
A resistor connected between this pin and ground sets the LED current.
Bottom LED cathode terminal.
Connect TAB to the Ground plane.
Pin Function
VIN is the supply pin for the device. A small 0.1 mF ceramic
bypass capacitor is optional for noisy environments. The
maximum operating voltage is 6.0 V. Whenever the input
supply falls below the under−voltage threshold, the current
sink will automatically be disabled.
EN/PWM is the enable and one wire dimming input for the
LED channel. 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 the
LED current is set at a gain of 400 times the current in RSET.
To place the device into zero current shutdown mode, the
EN/PWM pin must be held low for 5 ms typical.
LED pin is connected to the bottom LED cathode and
provides a regulated current sink. The pin enters a
high−impedance zero−current state whenever the device is
placed in shutdown mode.
RSET pin is connected to an external resistor to set the LED
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 sink. 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 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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