Description

The IS3751 is a DMX512 protocol-specialized integrated circuit that continuously generates addressable LED data from the received DMX data. It operates fully autonomously and does not require any external commands from a microcontroller or processor.

The chip operates at 3.3 V and supports both 3-color and 4-color addressable LEDs.

The addressable LED refresh rate is directly tied to the DMX refresh rate, typically around 40 Hz.

When controlling 3‑color addressable LED, the chip groups every 3 DMX channels into one LED. For example, channel 1, 2 and 3 control the colors of the first LED; channels 4, 5 and 6 control the second LED, and so on, up to LED 170.

When controlling 4‑color addressable LED, the chip groups every four DMX channels into one LED. For example, channels 1, 2, 3 and 4 control the 4 colors of the first LED; channels 5, 6, 7 and 8 control the second LED, and so on, up to LED 128.

The chip is color‑agnostic, DMX channel 1 will be mapped to the first color of the first LED, which may be red in some LEDs or green in others.

The maximum number of 3-color LEDs that can be controlled is 170, corresponding to DMX channels 1–510 (channels 511 and 512 remain unused).

The maximum number of 4-color LEDs that can be controlled is 128, corresponding to the full range of DMX channels 1–512.

This addressable LED driver IC is designed for developing custom LED fixtures compatible with the DMX protocol—without any need for firmware development—significantly reducing engineering costs and achieving a faster time-to-market.

The chip applications include:

• Custom lighting

• LED strips, panels and bars

• Floodlights and wall washers

• Building facades, bridges and monuments

• Interior design lighting

• Water fountains

• Museum lighting

• Stage and entertainment lighting

• Digital art installations

• Animatronics

• OEM / Device Manufacturers

According to the DMX512 standard, this protocol must never be used to control pyrotechnics or stage robotics, as it has no intrinsic error checking. Therefore, this chip should not be used for those applications either.

A minimum of approximately 130 DMX channels must be received to allow all addressable LED data to be fully transmitted. Receiving DMX data for a shorter duration than the addressable LED frame generation time is not allowed.

The DMX data enters the chip through the RX pin at TTL-compatible voltage levels. Since DMX uses differential signaling, an RS485 transceiver or receiver must be used to convert the differential DMX signal to TTL-compatible voltage levels. The RX pin operates at 3.3 V and is 5 V-tolerant, allowing the use of either 3.3 V or 5 V transceivers or receivers.

The LEDS pin outputs the addressable LED data. This pin is open-collector and must be pulled up to 5 V with a 500 Ω resistor to generate the 5 V data required by the addressable LEDs.

The TYPE pin selects whether the connected addressable LEDs are 3-color or 4-color, and the ACT pin can drive a standard LED that blinks when DMX data is detected on the RX pin. Its purpose is to easily indicate that the device is properly connected and receiving data.

The chip is compatible with addressable LEDs such as WS2811, WS2812 / WS2812B / WS2812C, WS2813, WS2815, NeoPixel, SK6812, GS8208, and any other LEDs that implement a compatible protocol.