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SN74LVT244B / Increasing the drive capability

Other Parts Discussed in Thread: SN74LVT244B, SN74LVTH16245A

Hi Everyone,

Our customer has evaluated to use SN74LVT244B with inserted configuration to increase the drive capability. Then can you give your comments for following questions?

  1. Can you recommend this configuration?
  2. Can you guarantee the specification when they use it within the recommended condition per channel?

Best Regards,

Sonoki / Japan Disty

  • This is OK if they keep the input lines electrically the same length. In other words the need the input signal to reach the part at the same time so there will be no bus contention.

    The part will still be in spec if they do this.

  • Hi,

    We are using SN74LVTH16245ADGG in one of our design to drive load of around 45pF, which includes 12 devices connected to the BUS TRANSCEIVER.

    The SN74LVTH16245A datasheet has CL=50pF.

    Will I face any reliability issue if I proceed with the design ? as CL value of 45pF is close to that of maximum CL.

    Awaiting your reply

    With Regards

    Bhanuprakash Nayak

    Member Technical

  • 50pf is simply a value that the parts are tested at.  LVT is high drive and can drive loads in th 100's of PF's.

    You should have no issues.

  • Hey Chris

    Thanks for your quick response.

    Regards

    Bhanuprakash Nayak

  • Hey Chris

    We are using the below TI components and we need the some info in order to do the Thermal Analysis.

    For component

    SN74LVC16T245DGGR and

    SN74ABT16374ADL

    Please provide the below details,
    Maximum Junction Temperature : Tj : 
    Junction to Case Thermal resistance ( °C/W) :
    Power Dissipation Max :
    Power Dissipation Typical :
    With Regards
    Bhanuprakash
  • Hi Bhanuprakash,

    I can create a thermal model for those two devices and have the data back to you in a few weeks (Junction-to-case resistance).

    Max junction temperature, Tj, is equal to the maximum storage temperature in the datasheet.

    Power dissipation depends on load and frequency. There is an application report here that describes CMOS calculations for power consumption. Although ABT is BiCMOS, there is still an ICC vs. frequency graph in that report: www.ti.com/lit/an/scaa035b/scaa035b.pdf

  • Dear C Ryan

    Thanks for your quick response.

    Please share the thermal model for the above mentioned two devices.

    With Regards

    Bhanuprakash

  • Hi Bhanuprakash,
    I apologize for the delay. The modeling team had people out of office for the U.S. holidays. Here is the data:

    SN7LVC16T245DGGR:
    Result- Theta JA-High K (standard datasheet value) 59.9
    Result-Theta JC, top (standard datasheet value) 13.9
    Result-Theta JB (standard datasheet value) 27.1
    Result- Psi JT (standard datasheet value) 0.5
    Result- Psi JB (standard datasheet value) 26.8

    SN74ABT16374ADL:
    Result- Theta JA-High K (standard datasheet value): 55.7
    Result-Theta JC, top (standard datasheet value): 26.1
    Result-Theta JB (standard datasheet value): 27.5
    Result- Psi JT (standard datasheet value): 5.5
    Result- Psi JB (standard datasheet value): 27.2