TS3A5018: ON-state resistance

Mike Hsu

Part Number: TS3A5018

Hi there

Q1. We use two TS3A5018 in series for SPI inerface. I noted in datasheet when the IC is operating at 1.8V supply, the ON-state resistance is relatively lower than 2.5V. (17 ohm VS. 20 ohm). Is that correct or typo?

Q2. Can we connect two TS3A5018 in series with NOx to NCx pin or vice versa?

Thanks

Mike Hsu

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 244370 points

1. The 1.8 V value is not plausible. And figure 1 does not show a curve for 1.8 V, and lots of other parameters are missing in section 6.8.

2. In theory, this should be no problem. I guess this is the same problem as TS3A5018: Is there limitation on number of series stage for TS3A5018RSVR?

0 Mike Hsu over 1 year ago in reply to Clemens Ladisch

Intellectual 300 points

hi Clemens

What is actual on-resistance value for 1.7V?

0 Tyler McGuire over 1 year ago

TI__Expert 3515 points

Hi Mike,

1. The RON value changes based on the voltage of the signal being passed. This E2E thread has data collected at 1.65V: TS3A5018: Ron variation with V+

2. Yes, 2 multiplexers can be used back to back but the bandwidth will be reduced. It is recommended to test the configuration with devices in the lab to make sure it will work for your application.

Thanks,
Tyler

0 Mike Hsu over 1 year ago in reply to Tyler McGuire

Intellectual 300 points

Hi there

I have used TI product searching tool as shown below

Analog switches & muxes product selection | TI.com

My question is if protocols column does not show it support SPI, it can not be used for SPI interface, right?

Thanks

Mike Hsu

+1 Clemens Ladisch over 1 year ago in reply to Mike Hsu

Guru 244370 points

Those protocols are just typical use cases, based on the number of channels. Switches support all signals inside their supported voltage and frequency range.

0 Mike Hsu over 1 year ago in reply to Clemens Ladisch

Intellectual 300 points

Do you recommand to add a series resistor like 22 ohm for SPI data and clock signal?

If yes, for impedance matching, reduce reflction, improve rising time?

+1 Clemens Ladisch over 1 year ago in reply to Mike Hsu

Guru 244370 points

This is a passive switch. Source termination would be needed only at the driver.

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TS3A5018: ON-state resistance