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SN74AHCT573: What is the different of SN74AHCT573 and SN74AC573

Part Number: SN74AHCT573
Other Parts Discussed in Thread: SN74AC573,

Hi Sir,

Could you please help on these 2 questions?

The application of SN74AHCT573 or SN74AC573 will be latches, FYI

Thank you

1. What is the different of SN74AHCT573 and SN74AC573? I just found the working temperature is different, is there any more different for these two?

2. Are Unused inputs connected direct to GND or pull-down resistor to GND? what's the pull down resistor value are you suggest?

  • Hi Anne,

    They are apart of different families so they will have varying specs, but both perform the same function. Please watch the training video below for more details on this.

    https://training.ti.com/tlm-bol-partnumber

    You can connect the unused inputs directly to ground.

  • Hi Anne,

    The primary difference between these devices is the logic family.  One is in the "AHCT" family, while the other is in the "AC" logic family. The 573 function is functionally identical in both families.

    You can find detailed information regarding the logic families in the Logic Guide. Here's some excerpts to help:

    These graphics show the input voltage requirements (VIH, VIL) and output voltage capabilities (VOH, VOL) of 5-V TTL and CMOS devices. The AHCT family is a TTL compatible CMOS family, so it adheres to the standard on the left, and the AC family adheres to the standard on the right.

    Additionally, there are full descriptions for each family that show some of the differences. Most notably, the AC family supports 24mA of output current, while the AHCT family only goes up to 8mA.