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TLV7032: Electrical Characteristics Interpolation

Austin Bergman
Prodigy 10 points
Part Number: TLV7032

In the TLV7032 datasheet, we see in section 6.9, the Electrical Characteristics (Dual) table, that the minimum, maximum, and typical values are provided assuming certain test conditions. Many of these test conditions involve the TLV7032 comparator being supplied with 5V. However, the comparator is capable of being powered via any voltage in the range of 1.6V to 6.5V. In the circuit we are using it in, we are powering the device with 3.3V. For parameters such as VOH, VOL, and ISC (short-circuit current) how would we go about determining the minimum or maximum value of that characteristic with a supply voltage of 3.3V? Can we interpolate these values from the values provided for a supply voltage of 5V? Is there any documentation that can be provided by TI that could support this discussion? For example, the VOH for the dual part has a minimum voltage of 4.65V with a supply voltage of 5V. So, would the minimum VOH be 3.3/5*4.65 = 3.07V for a supply voltage of 3.3V? 

  • 0
    Guru 276530 points

    If it is not specified in the electrical characteristics table, then it is not guaranteed.

    You can get typical values from figures 6-18…6-25. A MOSFET's RDS(on) depends on the gate-to-source voltage, so the drive strength decreases with supply voltage (not necessarily linearly).

    At 5 V, the worst-case output impedance is (VCC − VOH) / IO = (5 V − 4.65 V) / 3 mA ≈ 117 Ω. The typical drive strength at 3.3 V is about half that at 5 V, so we can estimate the worst case as VCC − IO × R ≈ 3.3 V − 3 mA × 233 Ω = 2.6 V. (But you would not use a 3 mA load at 3.3 V. And if the current becomes too large, the transistor saturates and RDS(on) is no longer constant.)