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Logic Buffer and Inverter have highest output current

Sam Guo
Prodigy 40 points
Other Parts Discussed in Thread: SN74LVC2G86, UCC27325

We need logic buffer and logic inverter to driver differential logic inputs with 200Ω differential loads.  The normal working temperature is 100°C to 125°C:

 

I found the following examples:

 

 

PN

function

Hi-mA

Low-mA

θja, °C/W

DigiKey Available?

SNJ54LVTH244AW

Buffer

-32

64

58

No

SN74LVTH245AMDBREP

Bus Tranceiver

-32

64

69.5

Yes

SNJ54LVTH541W

Buffer

-32

64

58

No

SNJ54LVTH240W

Inverter

-32

64

58

No

 

 

Please find proper parts:

  1. At least -40°C to 125°C.
  2. Low °C/W.
  3. Larger Driving Current.
  4. Short lead time.
  • 0
    TI__Guru* 96711 points

    Hi Sam,

    A 200 ohm load at 5V supply is only 25mA, so there are many options of devices that can support this. Usually the place you will run into trouble is with the maximum total current for a logic device - they aren't really designed for driving this much power continually on all of the outputs simultaneously.

    I'm not sure why you have selected TTL-compatible, military rated, bus-hold devices. Are these all requirements for your system?

    Is the supply 5V?

    What's the output loading (only 200 ohms, or also a capacitive load / transmission line)?

    Operating frequency?

    How many channels are required?

  • 0
    Guru 270700 points

    The logic family with the strongest symmetric output drive is LVC (±32 mA at 5 V). You could use the SN74LVC2G86 to have both buffer and inverter in one device.

    For even higher drive strength, use a gate driver like the UCC27325 (rated for ±200 mA); it is also available in the HVSSOP package with thermal pad.