Overview
The IS31LT3117 is a 4-channel, linear regulated,
constant current LED driver which can provide 4 equal
currents outputs of up to 350mA per channel to drive
high brightness LEDs over an input voltage range of
6V to 53V, while maintaining an output leakage current
of less than 1µA. The output current is easily
programmed using a single, tiny external resistor. The
outputs of the IS31LT3117 can be connected in
parallel to allow greater than 350mA output current.
The IS31LT3117 also features a PWM input to enable
simple dimming control using a digital control signal.
The recommended frequency range of the PWM signal
is 4kHz ~ 100kHz.
The IS31LT3117 provides a unique over temperature
protection scheme. A hard shutdown which turns off all
LED currents occurs if the die junction temperature
exceeds the maximum value of 160°C. However, as
the die junction temperature rises up to over 130°C
(Typ.), the output current will begin to roll off at a rate
of -2.22%/°C (Typ.). If the die temperature continues to
rise above the hard shutdown temperature threshold,
the LED currents will drop to zero. When temperature
returns to 140°C (Typ.) or below, the hard shutdown
protection is released and the chip will function again.
The IS31LT3117 also has an optional 2.5V reference
voltage output which is able to supply up to 10mA (typ.)
output current. This voltage may be used to drive the
base of the external BJTs for higher current
applications in such case, driving for a wide varying
input voltage is needed.
The IS31LT3117 is offered in eTSSOP-16 package
with operating temperature range of -40°C to +125°C.