IS32LT3128A-ZLA3-TR - RI-YAO Electronics Ltd.

Status	Sample
Vdd(V)	5~42
Dimming	BCM PWM, Switch Low Priority
Channels	3
Document
IOUT(mA)	20~150
Pkg-Pin(mm)	eTSSOP-20
Sink Source	Source
Product Family	32 = Automotive Analog and Mixed Signal
Part Number	3128 = 3128
Product Type	LT = Lighting LED Driver
Temperature Grade	A3 = Automotive temp. (-40°C to 125°C)
Package option	TR = Tape & Reel
Solder Type	L = Lead-free (RoHS Compliant)
Package Type	Z = TSSOP
Outpack	Tape on Reel

IS32LT3128A-ZLA3-TR Features

Operating voltage range, 5V to 42V
Dual channel current sources
- Individual programmable current via a single external resistor - Configurable from 20mA to 150mA
Single channel 30mA (max) current source for switch illumination
EN input supports either momentary contact or latched switch
- Input is debounced and latched - Lower priority than PWM input - Gamma corrected Fade ON/OFF algorithm - Pull down resistors set independent fade ON and OFF ramp time
Selectable external or internal PWM source
Fault Protection:
- Fault Reporting  LED strings short  Over temperature thermal shutdown - ISET pin shorted to GND - Over temperature current roll off
AEC-Q100 Qualified in progress
Operating temperature range from -40°C ~ +125°C

Overview

The IS32LT3128A is a programmable triple channel linear current regulator; two channels of up to 150mA each for LED lighting and a single channel of up to 30mA for illuminating switches. The device operates as a fully configurable theatrical dimming LED driver; no microcontroller is required. External resistors will program the current levels as well as the LED fade ON/OFF ramp rate. Additional configuration such as PWM source (internal or external), polarity (positive or negative) and switch type (momentary contact or latched) are selectable via the MODE1/2 pins. An integrated debounce and latch circuit on the channel enable pin (EN1/2) is enabled when the device is configured for a momentary contact switch interface. The other option is to configure the EN pins to accept a static level signal for operation with latched switches. A VCC level PWM dimming signal can be connected to the PWM input pin to directly drive both LED channels. If configured for Internal-PWM-Dimming mode, the integrated PWM source will be triggered by a PWM pin voltage level. This enables LED dimming without the need for an external PWM input. The PWM input have a higher priority and will override the EN inputs. See Figure 60~66 for the details. The device integrates a 63 step fade ON/OFF algorithm (Gamma correction) which causes the output LED brightness to gradually ramp up to the full source value after the EN1/2 or PWM (when configured for Internal-PWM-Dimming mode) pins are triggered. The same controller causes the LED brightness to gradually ramp down to zero if the EN1/2 or PWM (when configured for Internal-PWM-Dimming mode) pins are triggered while the output channel is ON. The fade ramp can be interrupted mid-cycle before completion of the ramp cycle. The IS32LT3128A is targeted at the automotive market with end applications to include map and dome lighting as well as exterior accent lighting. For 12V automotive applications the low dropout driver can support 1 to 3 LEDs (VF = 3.2V) per channel. It is offered in a small thermally enhanced eTSSOP-20 package.