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LSF0102: Does the device has one-shot?

Naveen Bevara
Intellectual 1970 points
Part Number: LSF0102
Other Parts Discussed in Thread: TCA9509, TXB0102, TXS0102

Hi, 

One of my customer is looking for 2 bit bi-directional level translator without one-shot and static power less than 200uA (static power + leakage). All the TXS and TXB family devices has the one-shot implementation. TCA9509 has more sleep current. I could find LSF0102 as the option with less Icc, and the datasheet does not mention about one-shot. But I could not see block diagram in the datasheet. Can you please confirm that the device has no one-shot implementation?  Also can it support arbitration and clock stretching? 

  • 0
    TI__Guru* 97046 points

    Hello Naveen,

    The LSF family of translators are completely passive.  Please check out this video series to learn more about them:

    Understanding the LSF Family of Bidirectional, Multi-Voltage Level Translators

    To be clear, there is no clock stretching, arbitration, or one-shot built into this device.

  • 0 in reply to Emrys Maier
    TI__Intellectual 1970 points
    Hi Emrys,

    Can you please suggest a device similar to TXS0102 or TXB0102 with below specifications:

    1. Without one shot
    2. Supports Arbitration and Clock Stretching Across
    3. Static power less than 200uA ( static power + leakage )
  • 0 in reply to Naveen Bevara
    TI__Guru* 97046 points
    Hello Naveen,
    There is not a single translator in the Standard Logic portfolio that contains "arbitration and clock stretching"

    Are you trying to replace a specific device? What is your goal?
  • 0 in reply to Naveen Bevara
    TI__Guru 62240 points
    Hi Naveen,

    Since the LSF is a passive translation device, it will support arbitration and clock stretching. This device also doesnt have oneshot and the static power consumption <200ua. The majority of the current is through the pullup resistors into the master/host devices.

    Please let us know if anything else.
  • 0 in reply to ShreyasRao
    TI__Intellectual 1970 points

    Hi Shreyas, 

    Before finalizing and suggesting to customer, can you please help me to clarify on below points.

    1. Has this been used in level translation earlier where arbitration and clock stretching is implemented? Because there are devices like TCA9509 where we mention in datasheet separately as "Supports Arbitration and Clock Stretchng", which is missing in this device datasheet. 

    2. LSF device acts as a passive switch when the input signal is below Vref_A – 0.5 V.  And in datasheet of TCA9509 it is mentioned that "It is important to note that any arbitration or clock stretching events require that the low level on the A-bus side at the input of the TCA9509 (VIL) be at or below VILC (150 mV) to be recognized by the TCA9509 and then transmitted to the B-bus side."

    a) Is VILC specific to level translator device or is it a standard voltage? 

    b) Does this mean any device which can support VIL < VILC can support arbitration and clock stretching? Apart from VIL level, is there any other specification that defines the part to support for clock stretching and arbitration? 

    c) Does LSF device has VIH range of only 0.5V? 

  • 0 in reply to Naveen Bevara
    TI__Guru 62240 points
    Naveen,

    Since the LSF is a generic translation device to support both the push pull and open drain interface, it will not be specific to mention I2C interface specific terms about clock stretching or arbitration.
    If the features should mention about the terms, then a I2C specific device must be considered.
    The LSF being a passive device, the output Vol is dependent on the input Vil and hence the Vil or Vih is not specified. The Vil / vih are also the terms which are referred to the active logic buffer devices.