| Status | Sample |
|---|---|
| Vdd(V) | 5~42 |
| Dimming | BCM PWM, Switch 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 |
The IS32LT3128 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 EN inputs have a higher priority and will override the PWM input. 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 IS32LT3128 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.