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SN74ACT7881_Suppply Voltage and IO Voltage

Vijetha HN
Intellectual 600 points
Other Parts Discussed in Thread: SN74ACT7814, SN74ACT7813, SN74ACT7806, SN74ACT7803, SN74ACT2229, SN74ACT2228, SN74ACT2226

Hi,

The FIFO part SN74ACT7881 suffices all our design requirements. But except the factor that its VCC is high (4.5V to 5V). The MCU we are interfacing with this FIFO works at IO level of 3.3V.

Hence we would like to confirm below points:

1. Can we provide 5V to VCC but interface this FIFO with 3.3V IO devices? Will it work?

2. If answer for 1st question is NO, then we are not interested in going for Translator ICs as it might affect our throughputs. Hence do you suggest any FIFO chip that has all features (FULL, EMPTY, HALF FULL/EMPTY), ALMOST FULL/EMPTY) similar to SN74ACT7881 with VCC and IO Voltages at 3.3V level.

Regards,

Vijetha

  • 0
    TI__Guru* 96681 points

    Hi Vijetha,

    I'm not familiar with the SN74ACT7881. These are the devices that are available from TI in the ACT FIFO logic category:

    Part number Description
    SN74ACT7814 64 x 18 asynchronous FIFO memory
    SN74ACT7813 64 x 18 synchronous FIFO memory
    SN74ACT7806 256 x 18 asynchronous FIFO memory
    SN74ACT7803 512 x 18 synchronous FIFO memory
    SN74ACT2229 256 x 1 x 2 dual independent synchronous FIFO memories
    SN74ACT2228 256 x 1 x 2 dual independent synchronous FIFO memories
    SN74ACT2227 64 x 1 x 2 dual independent synchronous FIFO memories
    SN74ACT2226 64 x 1 x 2 dual independent synchronous FIFO memories

    The ACT family in general has TTL compatible inputs with an input low voltage of 0.8V (max) and an input high voltage of 2V (min), so a typical 3.3V signal will register as a valid input. 

    The outputs will be the same as the supply voltage (5V typ).

  • 0 in reply to Emrys Maier
    Intellectual 600 points

    Can I get any FIFO IC with output also compatible to 3.3V ?

  • 0 in reply to Vijetha HN
    TI__Guru* 96681 points

    Hi Vijetha,

    We don't have very many FIFO registers - did you try looking at the ones we have?  The V series family only operates at 3.3V, so that might work for you. Here's a link to the page that has the list:

    https://www.ti.com/logic-circuit/flip-flop-latch-register/fifo-register/products.html