topic PCA9615 Failures in Other NXP Products

PCA9615 Failures

Staff — Sat, 03 Jul 2021 20:31:33 GMT

Hi, Forum,

The circuit below is used on both ends of a 10-foot cable. The PCA9615 I.C.s catastrophically and permanently fail, sometimes at both ends of cable simultaneously. Failed I.C.s drag down our power supply and get hot - they die. Replacing the I.C.s fixes the problem.

Failures may occur after hours or days of normal operation, or immediately after a disconnect/reconnect, and possible after (unauthorized) hot-swapping. The cable carries the PCA9615 dual differential bus, ground, and +24V. +5V and +3V are generated from +24V independently at each end of the cable. We are not using the hot-swap logic, but have EN tied to +3.3V. The datasheet includes no Limiting Values identified for hot-swap, and its hot-swap description mentions nothing about protecting the I.C., so I presume the hot-swap logic is intended not to protect the device from damage, but to prevent the device from corrupting data when connected to a live bus.

The failure can be recreated by intentionally hot-swapping under ESD-safe conditions, so failures are probably not likely cause by ESD.

No microcontroller is available to operate the hot-swap EN signal at one end of the cable.

Is hot-swapping without using the hot-swap logic known to cause device failures?

What is the failure mechanism?

The PCA9615 is a nice, inexpensive, compact solution to extending I2C through a cable. We'd like to keep using it, and we want to keep using it if possible.

Suggestions?

Re: PCA9615 Failures

guoweisun — Wed, 14 Jul 2021 03:21:34 GMT

For the unused of hot swap function, floating the EN pin because of it connect with VDDA inside of IC.

Re: PCA9615 Failures

aferm — Thu, 20 Jan 2022 21:57:02 GMT

I am having similar issues with heat and communication failure. VDD(A) = 3.3V, VDD(B) = 5V, EN = floating, no hot-swap.

Re: PCA9615 Failures

jmse — Mon, 23 Jan 2023 15:45:20 GMT

I also have the same issue, VDDA = 3.3V, VDDB= 3.3V. and it all seems to be happening during hot plugging operations (also under ESD safe environment). Once the PCA9615 fails it won't recover, and the PCA9615 starts getting really hot.

Re: PCA9615 Failures

Satyabobbadi — Thu, 11 Jul 2024 09:32:55 GMT

I am also facing the same issue, can this be recovered with a power cycle? how to resolve the issue if the communication is throwing an error during the hot swapping. please clarify in detail.