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SN74CBTLV3251: SN74CBTLV3251 vs SN74CB3Q3251 vs TMUX1108

AJ
Intellectual 570 points
Part Number: SN74CBTLV3251
Other Parts Discussed in Thread: SN74CB3Q3251, TMUX1108

Hello TI Support,

Can you please explain main difference between SN74CB3Q3251 ($0.17) and SN74CBTLV3251 ($0.25)

If I understand correctly, both devices support partial power off (Ioff) and as per datasheets

SN74CB3Q3251    Ioff = 1uA
SN74CBTLV3251  Ioff = 20uA

SN74CB3Q3251 can switch input signal levels beyond supply rail, i.e. 0 to 5V @ Vcc = 3.3V
SN74CBTLV3251  switches  0 < VIN < Vcc

Both are footprint compatible and the SN74CB3Q3251 is also cheaper... Any reason why SN74CBTLV3251  over SN74CB3Q3251?

Do you have any information on cross-talk performance?
Also, I don't see any leakage information - can you please recommend Opamp to interface with SN74CB3Q3251?

 
TMUX1108 is promising for low power / precision application but @ ~10x the cost of SN74CB3Q3251 I am unable to justify it
Can you please confirm if TMUX1108 support partial power off as well?


Best,
AJ

  • 0
    TI__Mastermind 48257 points

    Hi Alex,

    So the difference between the two parts is actually is architecture. The CBTLV is using a transmission gate architecture while the CB3Q uses an NFET and a charge pump based switch. This means that the CB3Q will have a higher power supply current which could affect efficiency for the system. 

    The reason you would pick the CBTLV above the CB3Q is if you are trying to conserve power, but that does come at the cost of performance, as the CB3Q can pass above the rails and has a lower capacitance because less Fets are used in the switch. 

    If power usage isn't your concern I would suggest the CB3Q part.

    For the leakage specs they are both max  +/- 1uA with the CB3Q being labeled I_OZ and the CBTLV being labeled I_l.

    Unfortunately we do not have cross-talk data for these parts. 

    I am not an Op-Amp expert, but we do have a couple application notes than can help narrow down your search and give you design tips for integrating multiplexers with Op-Amps

    1. Mux Friendly Precision Op Amps

    2. Improve Stability with Low Con Muxes

    If this doesn't help you, one of our Amplifier Experts can help you select an Op-Amp in the  Op-Amp Forum:

    2. Forum

    As for the TMUX1108 it does not support partial power down. 

    If you have any other questions don't hesitate to reach out!

    Best,

    Parker Dodson

  • 0 in reply to Parker Dodson
    Intellectual 570 points

    Hellp Parker,

    Thank you for the prompt response and links.

    It's clear now.

    Best,

    AJ