SC18IS602B I2C to SPI Bridge Latch-Up Issue

[eltonwang]

Hello,

We are facing SC18IS602B I2C to SPI bridge Latch-Up issue after power down system (from S0-S5-G3).

The failure rate is around 0.26% (4pcs out of 1500pcs)

We take this part in Intel x86 platform to convert data from embedded controller IT5121VG to battery charger LTC1960CG#TRPBF (SS0#).

It was found the VDD(3.3V) has voltage remained (0.3V) during power off. It needs to take a time for fully discharging remained power.

The latch-up occurred after next power up with VDD remaining power 0.3V. The failure rate is not 100% but close to 10%.

Pulling RESET# signal to low cannot fix latch-up issue when problem occurred. 

We would like to clarify some items:

1) What's the latch-up condition of this part ?

2) What's the voltage threshold of power on reset(POR) for this part ?

[reyes]

Hi,

1. Latch-up depends on the pin configuration and the conditions are explained on sections 7.1.11.1, 7.1.11.2, 7.1.11.3 and 7.1.11.4 of the devices datasheet: https://www.nxp.com/docs/en/data-sheet/SC18IS602B.pdf

2. It is the HIGH-LOW threshold voltage of MIN = 0.22VDD and TYP.=0.4VDD.

And LOW-HIGH threshold voltage of TYP = 0.6VDD and MAX = 0.7VDD

Regards,

Jose