LTM2889HY-3#PBF: An Isolated 4Mbps CAN FD Transceiver

Isolating some parts or components of an Integrated Circuit (IC) has become the norm today. However, the isolation works best if it is targeted at a specific area or function. LTM2889HY-3#PBF doubles as an isolated CAN FD transceiver – and one with support for the Micromodule (µModule).

In this blog post, you will learn how a CAN transceiver works and some of the attributes of this LTM2889HY-3#PBF CAN FD Transceiver.

What is a CAN Transceiver?

First, let us break down the first concept – CAN. It stands for Controller Area Network. According to Wikipedia, a CAN or a CAN bus is a “robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other’s applications without a host computer.”

EasyTechJunkie adds that the CAN transceiver enables seamless communications and data transfer across the different digital parts of a computer.

Digi-Key adds that a Controller Area Network (CAN) is a part of the many specialized ICs. These are dedicated Integrated Circuits (ICs), manufactured to carry out or implement different (specific) functions.

On its part, LTM2889HY-3#PBF is a complete galvanically-isolated Controller Area Network (CAN) µModule (Micromodule) transceiver. As such, it is optimized along the lines of connecting multiple devices together to the same port or network, while maintaining the respective isolated performances of these devices.

The Isolated Functions

We already mentioned that LTM2889HY-3#PBF isolates the core devices – but how does it do that? It is able to isolate these devices or components through the combined use of the isolation power transformer and the coupled inductors. The combination paves the way for the provision of up to 2500VRMS of isolation between the logic interface and the line transceiver.

Uninterrupted Communication

It may seem contradictory to say that information or communication transmission is still very much active despite the isolation of the line transceiver and the logic interface. However, it is true that communication is not entirely interrupted – and that is because of the enabled communication for the common mode transients that are typically greater than 30kV/µs.

LTM2889HY-3#PBF Doesn’t Need External Components

LTM2889HY-3#PBF does not need an extra set of components to function optimally. The zero-need for external components is because LTM2889HY-3#PBF uses a single supply, which provides power supply for the both sides of the interface. The power supply is provided via an integrated, isolated DC/DC converter.

The CAN Transceiver: How It Works

LTM2889HY-3#PBF is an isolated Controller Area Network (CAN) with a unique performance standard.

We are now going to talk about some of the functionalities that make up its CAN transceiver:

1. Wide Common Mode Operating Range

LTM2889HY-3#PBF supports up to ±36V of extended common mode operating range. This range makes it an ideal CAN transceiver for performance-centric applications.

Worthy of mentioning is that the operating range can vary depending on where it is used. For example, it can be between -25V and 25V when operating from a 3.3V VCC2 supply. However, the common mode operating range can spike to -36V and 33V when operating from a 5V VCC2 supply (GND2-wise). The operating range can also vary by other conditions.

Generally, the main idea about LTM2889HY-3#PBF’s common mode operating range is that it permits the transceiver (LTM2889HY-3#PBF) to facilitate the transfer of data under the otherwise adverse conditions that could have negatively impacted the process.

Noteworthy also is that LTM2889HY-3#PBF’s common mode operating range aids in the transceiver’s increased reliability, especially in the environments with a higher common mode voltage. Such environment is typically created after noticeable ground differences are spotted between on the bus nodes on the isolated part/side of the network and this could be because of loops on the ground.

Another environment that could trigger LTM2889HY-3#PBF’s increased reliability usage is the creation of higher common mode voltages because of the electrical noise generated in the process.

2. High-Speed Data Transmission

LTM2889HY-3#PBF is able to transmit or transfer data faster because of the high-speed architecture. The architecture encompasses the combined function of the high-speed transmitter and receiver, which can deliver up to 4 Megabytes per second data transmission.

However, the speediness of this data transmission relies on the transceiver’s configuration. The best way to get this result is to set the transmitter at its maximum slew rate. The process of doing this includes pulling an output impedance of the buffer to drive the RS input; and pulling the RS pin low to the GND2 pin, while avoiding the exceeding of the 4k resistance.

3. Fault Protection

Definitely, when the transceiver has been discovered to contain some faults, it is possible that “everything would come crashing down.” However, the detection of the fault on time doesn’t always translate to a quick-fix for the issue.

That is the reason why LTM2889HY-3#PBF’s ±60V Fault Protection is a better mechanism to prevent much damage from happening. It is implemented on the core CAN Bus interface pins, such as the SPLIT, CANH and CANL pins.

The implementation at any of these pins paves the way for advanced transceiver protection at all the stages of operation. It also provides other protective mechanisms, such as power off, dominant and recessive states; and shutdown functions.

Besides, the driver outputs allow for the dual functionalities, whereby the transceiver can alternate between the currents. For example, the use of a progressive foldback current limit protects the transceiver against overvoltage faults. At the same time, it allows for the high-current output driver to still function.

Product Attributes

Below are some of the attributes of this CAN FD transceiver:

AttributesDescription
Mounting StyleSurface-mount
Type of ProductIsolated transceiver
Package/Case32-BBGA Module
Packaging TypeTray
Base Product NumberLTM2889
Typical ApplicationsIndustrial, CAN and DeviceNet

LTM2889HY-3#PBF: Wrapping Up

LTM2889HY-3#PBF makes the process of connecting multiple devices to one network or interface while maintaining an isolated state a breeze. With this transceiver, it is possible to make an isolated transmission of data at an estimated speed of 4 Mbps.

The transceiver also supports a wide range of other functions, including an ambient operation of up to 125˚C, no external components required and easy interfacing with different logic levels.