SN74CB3Q3257: Do you have a 4:1 mux with 1.8 V supply voltage and support SPI and I2C signals

Hi, 

Thank you for your question. 

First, could you confirm which voltage specification the 1.8V specification is referring to? Is it the voltage supply, voltage of the signal passing through, or the logic level of the select/enable pin? We have switches that cover all three of these. I only ask because 1.8V is becoming a frequently used logic level for the select/enable pin. Also, our CB3Q devices have integrated charge pumps that allow the switch to pass a signal voltage greater than the supply voltage. For example,  SN74CB3Q3257 can pass a signal voltage from 0 to 5V with a 3.3V supply. So this device will pass a 1.8V signal, but it will not be able to work off of a 1.8V supply rail. 

Solution for 4-Channel, 2:1 (1.8V version of SN74CB3Q3257)

Assuming that you need to pass a signal up to 1.8V powered by a 1.8V rail (as we call "rail-to-rail"), I was able to find the following solutions using our Parametric Search Table, which can be found at ti.com/switches under Analog Switches and Multiplexers' Products tab. Either TS3A44159 or TS3A5018 will work, depending on your on-state resistance (Ron) or cost needs. 

Solution for 2-Channel, 4:1 (1.8V version of SN74CBT3253)

Also, assuming that you need to pass a signal up to 1.8V powered by a 1.8V rail (as we call "rail-to-rail"). There are two possible solutions with our existing devices. 

1. Use a higher power rail ( >2V ) to pass a signal up to 1.8V

   

2. Cascade multiple 1-Channel 2:1 muxes than can run off of a 1.8V rail

From our Quick Search, I was able to find many devices here that could work. 

If on-state resistance (Ron) is very important to the customer, I would recommend TS5A4624 (Ron typ = 0.5 Ohms). If a low cost solution is important to the customer, I would recommend SN74LVC1G3157 (1Ku = $0.05). 

We will take your 1.8V feedback into consideration for the future.