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SN74AXC4T774: SN74AXC4T774

Ishwar Sharma
Prodigy 160 points
Part Number: SN74AXC4T774

Tool/software:

Hi,

We are looking this device for Test (ATE) applications where different data protocols (as SPI, JTAG etc.) are running.

One side (VCCA) we will have fixed Input signal voltage as 3.3V and another side (VCCB) there will be programmable signal voltages from 0.8V to 2.5V (in steps of 50mV) for unidirectional (An to Bn) application with up to 100 MHz data speed and with Push-Pull type input. We will provide programmable supply through DAC to VCCB according to output signal voltage requirement.

We are looking device with minimum Propagation delay ≤1ns for 100 MHz data speed applications.

Requirements as below for Down Translation from 3.3V to (0.8V to 2.5V):

1. Input voltage (VCCA) will be fixed 3.3V (Push-Pull Type and Bandwidth up to 100 MHz)

2. Output voltage (VCCB) will be from 0.8V to 2.5V (in steps of 50mV)

3. Signal bandwidth is needed up to 100 MHz for full output range from 0.8V to 2.5V (in steps of 50mV) for down translation.

4. Propagation delay is needed ≤1ns for full output range from 0.8V to 2.5V (in steps of 50mV) for down translation.

5. Operating Temperature range is 0 to 50 Degree C

We have seen the Propagation delay (Pd) in datasheet given for Min (0.5ns) and Max values (5-10ns) only not Typical values. How can we calculate/estimate Propagation Delay (Pd) for Typical values (at 25 Degree C) and at 50 Degree C.

Please suggest if this part suitable as per our requirements..

Can you please also share SPICE Model for this part to simulate the performance.

Best regards

Best regards

  • 0
    TI__Mastermind 22840 points

    Hello Ishwar,

    I would look into the SN74AXC4T774. This part gives you the flexibility to change all I/Os pins to any direction. Meaning it can be configured to support SPI, JTAG, UART and so on.

    Here are the propagation delay values translating down from 3.3V to 0.8V (and 2.5V)

    Regards,

    Josh

  • 0 in reply to Joshua Salinas
    Prodigy 160 points

    Hi Josh

    Thanks for update for SN74AXC4T774 device.

    Actually, you have shown here Max and Min values for Propagation delay for translating down.

    I have still some queries as below.

    1. Min Propagation delay is shown for which conditions ? Is it at -40 Degree C ?

    2. Max Propagation delay is shown for which conditions ? Is it at 85 Degree / 125 degree C ?

    3. What will be Typical propagation delay at 25 degree C for each voltage (0.8V to 2.5V)  for down translation ?

    4. What will signal bandwidth (MHz) supported for each voltage (0.8V to 2.5V) for down translation ?

    Is there any way/formula to calculate/estimate the propagation delay at required operating temperature like using temperature coefficient etc.?

    Is there any way/formula to calculate/estimate the signal bandwidth (MHz) for each voltage (0.8V - 2.5V) down translation at different operating temperature. required ?

    Best regards

  • 0 in reply to Ishwar Sharma
    TI__Mastermind 22840 points

    Hello Ishwar,

    To answer questions 1, 2, and 3, all the min and max conditions are captured across temperature. Meaning -40C to 85C for commercial devices (like the one I posted above) or -40C to 125C for automotive devices.

    We only have min and max values, no typical (25C) data was captured.

    For questions 4, we can approximate the bandwidth by using the following formula 1/tpd. For example, using VCCA = 3.3V, VCCB = 0.8V and tpd =9ns, bandwidth would be 111Mbps.

    Hope this helps.

    Regards,

    Josh