TMUX1574: Support on Internal architecture and pull up required on MUX (S side)

Narender Mariappan

Part Number: TMUX1574

Tool/software:

HI ,

We are using TMUX1574 mux in our design. One end of the mux (Drain / D side) is connected to QSPI Flash memory, the other end (Source / S Side) is connected to FPGA Banks. There is a XTP Checklist for FPGA which recommends to connect a pull-up resistor on the Flash Side for (Chip select, DQ2,DQ3).Since it is not an end to end connection (FPGA to Flash Memory).

I have attached an image FYR. Kindly check and tell.

1. Do we require a pull up resistor on the (Source / S Side) of the MUX?

2.Can you share the Internal architecture diagram (Whether it is a MOSFET or any other switch used) of the MUX ?

15 days ago

0 Nir Gilgur 15 days ago

TI__Expert 7365 points

Hello Narender,

I am not familiar with the XTP checklist you are referencing, but I don't believe you are required to do so. The TMUX1574 has powered off protection. It provides isolation when the supply voltage is removed.

I can't share a diagram of the architecture, but it is an NFET with a charge pump. For more information on our switches architecture please check out our FAQ.

Thanks,

Nir

0 Clemens Ladisch 15 days ago

Guru 272990 points

1. The TMUX1574 itself does not care. You might need a pull-up or pull-down for any input pin that can be disconnected from the signal source, to prevent it from floating.

2. The TMUX1574 uses N-channel MOSFETs with a charge pump; see [FAQ] What are the Types of Architectures TI Switches and Multiplexers Use and how do I know which one my device has internally?

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TMUX1574: Support on Internal architecture and pull up required on MUX (S side)