SN54LVCH244A-SP: balanced outputs and bus hold

Andrea Pastega

Part Number: SN54LVCH244A-SP
Other Parts Discussed in Thread: SN54AC244-SP, SN54LVC14A-SP

Hi,

I would use an SN54LVCH244A-SP with each group of 4bits with inputs and outputs strapped together, in way to increase output current.

Standard LVC logic should have balanced outputs feature, allowing strapping of adjacent bits.

I have a concern about bus hold feature: can it work as expected, provided that higher current shall be supplied at input to trip bus hold (for 4bits strapped at least 500uA*4 = 2mA)?

I would prefer an LVC version without bus hold, but I think this version is not available for Radiation Hardened/Tolerant applications.

Thanks

Andrea

over 2 years ago

+1 Clemens Ladisch over 2 years ago

Guru 316940 points

All CMOS devices allow their outputs to be paralleled; see [FAQ] Can I connect two outputs from a CMOS logic device together directly?

You can use bus-hold inputs in parallel if the other device has enough drive strength. If in doubt, put another buffer in front of it.

The SN54AC244-SP has no bus hold, but its drive strength is 12 mA at 3.3 V.

The SN54LVC14A-SP has six inverting channels.

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SN54LVCH244A-SP: balanced outputs and bus hold