Why is the NXP PCA82C251 CAN tranceiver disliked? - Page 1
Forum section: electronics / projects

author: AndersJ
author_rank: Frequent Contributor
timestamp: March 30, 2017, 07:19:11 pm
content: I have seen in forums, including this one, that the PCA82C251 is sometimes not recommended.But i have never heard any motivations.Does anyone have reasons to avoid using it?If so, what is wrong with it?What is recommended instead, and why?

author: Niklas
author_rank: Frequent Contributor
timestamp: March 30, 2017, 08:13:09 pm
content: I have seen it on a few OEMs' blacklist together with some other older CAN transceivers. No direct motivation, just "we don't accept this part". What I suspect is the main reason is asymmetric drive performance and timing on CANH and CANL, causing disturbances on the differential signal CANH-CANL. This is also one of the reasons why common mode chokes were mandatory earlier. With today's CAN FD, the transceivers are better matched to handle the higher data rates.

author: Jeroen3
author_rank: Super Contributor
timestamp: March 30, 2017, 08:27:05 pm
content: Supply chain could be problematic due to it being a famous part and clones.

author: AndersJ
author_rank: Frequent Contributor
timestamp: May 17, 2021, 12:57:50 pm
content: Any suggestions for functional and pinout equivalents?Reasons to change?

author: Niklas
author_rank: Frequent Contributor
timestamp: May 18, 2021, 07:52:20 pm
content: I would suggest: TI TCAN1051/TCAN1057 (new, proto), NXP TJA1051/TJA1057, ON Semi NCV7351/NCV7357 or Microchip MCP2557. Just double check the last characters of the part number so you don't get the version with separate supply for the logic interface. Pin 5 should not be Vio.

author: AndersJ
author_rank: Frequent Contributor
timestamp: May 18, 2021, 09:04:32 pm
content: I found:* SN65HVD255D* MCP2561FD* LTC2875IS8Any thoughts on these?

author: Niklas
author_rank: Frequent Contributor
timestamp: May 20, 2021, 09:10:11 pm
content: They should all work. Note that if you need to pass a miswiring test on a 24V vehicle system, the TI part might be on the limit with -27V rating. The parts that I listed previously are parts that I am about to evaluate as replacements for an older ON Semi part.

author: rvalente
author_rank: Frequent Contributor
timestamp: May 21, 2021, 01:03:53 pm
content: TLE9250 from infineon is pretty common as well.Older TJA1040 and 1041 dominated the market 10 years ago and usually the did not required the common mode choke

author: AndersJ
author_rank: Frequent Contributor
timestamp: May 21, 2021, 02:08:28 pm
content: Many older devices are made according to ISO-11898.Newer ones implement ISO-11898-2I have not been able to figure out what the major and most important differences are.Can anyone comment on the differences, and describe when and how they are of importance?

author: Niklas
author_rank: Frequent Contributor
timestamp: May 22, 2021, 07:20:55 pm
content: The difference is more on the high level protocol side. The original spec has branched into several variants based on needs for different applications.https://en.m.wikipedia.org/wiki/CAN_busWhen it comes to the transceivers, the major development has been towards faster baudrate and some of the newer ones can go up to 8 Mbit/s. There are also variants with a separate supply pin for the logic interface to remove the need for level translators.

author: AndersJ
author_rank: Frequent Contributor
timestamp: May 23, 2021, 12:06:53 pm
content: I have somehow been led to believe that -2 specifies a lower capacitive load on nodesand therefore allowing more nodes and longer cables than previously.Unfortunately I’m unable to find that now.Am I wrong here?