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TCA9539-Q1: Power Dissipation Input and VOH and VOL Query

vikas gupta1
Intellectual 525 points
Part Number: TCA9539-Q1

Hi,

We are using TCA9539-Q1 at our product design and needed below clarifications please help :

1. What is the typical and absolute Power dissipation the device can handle.

2. Why there is multiple values mentioned in datasheet for VOH and VOL levels , which value we can consider and how to decide on those values, please refer page 5 of datasheet.

3. Page 4 mention absolute maximum ranges , can we get definitions of some parameters like Input/Output Clamp current.

Thanks

Vikas G.

  • 0
    TI__Guru 62920 points

    Hi Vikas,

    We will get back to you regarding these questions within the next couple of days.

    Regards,

    Max

  • 0
    TI__Guru 50795 points

    Hi Vikas,

    1. What is the typical and absolute Power dissipation the device can handle.
    This depends on the device's junction temperature and the type of load being driven. In datasheet section 6.3, the recommended output current limits of the i/o pins are listed relative to junction temperature. Because the device needs to remain below a certain temperature to maintain functionality, decreasing the device junction temperature will allow it to dissipate more power as heat. Sustainable supply current also depends on the type of load. This device has different driving capabilities when sourcing current from Vcc vs sinking current to ground (see section 6.1 "Absolute Maximum Ratings"). Section 9.2.1 "Design Requirements" has information on calculating device Power Dissipation with relation to junction temperature as well as a section on Icc when driving LEDs. Let me know if you have further questions on these sections or similar specifications.

    2. Why there is multiple values mentioned in datasheet for VOH and VOL levels , which value we can consider and how to decide on those values, please refer page 5 of datasheet.
    Section 6.5 "Electrical Characteristics" defines Output Voltage/Current levels for P-port pins as well as interface pins SDA and nINT. The P-port pins define these values across a range of supply voltages and loads. When more current is drawn by a load on one of these pins, it becomes more difficult  to drive the voltage to the desired level. Defining these values throughout the given ranges is done to provide expected device behaviors based on system requirements. 

    3. Page 4 mention absolute maximum ranges , can we get definitions of some parameters like Input/Output Clamp current.
    Input/Output clamp current defines the capabilities of protection diodes on input/output pins. These protection diodes offer a path to ground to clamp voltages that may exceed the absolute maximum at that pin. The datasheet defines "Thee input negative voltage and output voltage ratings may be exceeded if the input and output current ratings are observed". 

    Let me know if these answers make sense.

    Regards,
    Eric