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DS90LT012A: DS90LT012A output is CMOS or TTL?

BX27
Genius 3900 points

Part Number: DS90LT012A

Hi there,

In page 1 of DS90LT012A datasheet, it isi said  this is a 1-channel CMOS differential line receivers. However, later pages, such as page 2,3,4,7,10 and some other places, it is described as TTL output.

We are confused which one is correct. Could you please explain this? Thanks.

  • 0
    TI__Mastermind 43795 points

    Hi,

    The output specifications are similar to many TTL or LVTTL devices, but the actual output is implemented as a CMOS design.  The output will pull all the way to VDD and GND.

    Regards,

    Lee 

  • 0 in reply to Lee Sledjeski
    Genius 3900 points
    Hi Lee
    I do not get your meaning very clear. As I know, for LVTTL3.3V and LVCMOS3.3V, their VOH and VOL threshold Definition is different. although the voltage value is close, but they are totally different Voltage Standards . Personally speaking, I think datasheet should have a consistant Description.
    Thanks.
  • 0 in reply to BX27
    TI__Mastermind 43795 points
    Hi,
    The "CMOS" in the title refers to the type of semiconductor fabrication process used to produce this design.
    The LVTTL or TTL OUT refers to the style of output specifications guaranteed by the electrical table. In the DS90LT012A implementation the output NMOS pulldown is stronger than the output PMOS pullup. This was done to match the 2mA IOL and -0.4mA IOH electrical specifications.

    If this device is connected to a high impedance load like a CMOS input, the PMOS output pullup will allow the VOH to go all the way to the VDD supply level. An oscilloscope probe connected to the output would see a signal that transitions between 0V and VDD.

    Regards,
    Lee