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TLV1805-Q1: output structure

Jay wang
Intellectual 1511 points
Part Number: TLV1805-Q1
Other Parts Discussed in Thread: TLV1805

hi experts

i have some questions about TLV1805-Q1.

Q1:what is the output structure of TLV1805-Q1? are there any internal diode in IC?

Q2: the following is SCH from <TIDA-010071>.what is the aim of "14V SMAJ14CA"? to protect the TLV1805-Q1 output pin?

Q3: if "PILOT_out" short to 16V without D15, is TLV1805-Q1 damaged?

  • 0
    TI__Guru 50016 points

    Hello Jay,

    Q1: it is a standard  complementary output consisting of N and P-channel NOSFET transistors.

    The inputs and output are protected by ESD didoes to the supplies. These didoes are always there, even in shutdown.

    Q2: The 14V SMAJ14CA is a bi-directional TVS diode to protect the circuit from external transients. External protection is always recommended when the signals come from "outside" the instrument.

    Q3: R54 will limit the total current to ±12mA. The TLV1805 may get a little warmer, but it will not be damaged.

    In a functioning system, the system should detect the short via the "PILOT_ADC" feedback monitor and throw an error flag (shut down).

  • 0 in reply to Paul Grohe
    TI__Intellectual 1511 points

    hi Paul 

    for Q3, what is the output diode max forward current?

  • 0 in reply to Jay wang
    TI__Guru 50016 points

    Hi Jay,

    10mA - same as the inputs. The ESD structures are similar.

    But we recommend keeping the currents to below 1mA if possible. ESD diodes are not meant to continuously dissipate power.

  • 0 in reply to Paul Grohe
    TI__Intellectual 1511 points

    if diode forward current max is 10mA,  it seems like that ±12mA as you mentioned before will damage IC.

  • +1 in reply to Jay wang
    TI__Guru 50016 points

    Hi Jay,

    That is current trough the ESD diode - not the output.

    The only way you would be pushing current through the diode is by forcing voltage greater than the supply into the output. The output cannot exceed the supplies on it's own.

    The output can go up to 90-100mA peak (limited by thermal dissipation).