8.3.1 Balanced CMOS Push-Pull Outputs

A balanced output allows the device to sink and source similar currents. The drive capability of this device creates fast edges into light loads so routing and load conditions should be considered to prevent ringing. Additionally, the outputs of this device are capable of driving larger currents than the device can sustain without being damaged. It is important for the power output of the device to be limited to avoid thermal runaway and damage due to over-current. The electrical and thermal limits defined the in the Absolute Maximum Ratings must be followed at all times.

8.3.2 Standard CMOS Inputs

Standard CMOS inputs are high impedance and are typically modelled as a resistor in parallel with the input capacitance given in the Electrical Characteristics. The worst case resistance is calculated with the maximum input voltage, given in the Absolute Maximum Ratings, and the maximum input leakage current, given in the Electrical Characteristics, using ohm's law (R = V ÷ I).

Signals applied to the inputs must have fast edge rates, as defined by Δt/Δv in Recommended Operating Conditions to avoid excessive currents and oscillations. If a slow or noisy input signal is required, a device with a Schmitt-trigger input should be used to condition the input signal prior to the standard CMOS input.

8.3.3 Clamp Diodes

The inputs and outputs to this device have negative clamping diodes.

Figure 5. Electrical Placement of Clamping Diodes for Each Input and Output

8.3.4 Partial Power Down (I_off)

The inputs and outputs for this device enter a high-impedance state when the supply voltage is 0 V. The maximum leakage into or out of any input or output pin on the device is specified by I_off in the Electrical Characteristics.

8.3.5 Overvoltage Tolerant Inputs

Input signals to this device can be driven above the supply voltage so long as they remain below the maximum input voltage value specified in the Absolute Maximum Ratings.

8.3.6 Output Enable

This device has an output enable (OE) pin that functions according to Table 1. When the outputs of the device are disabled, they are placed into a high impedance state where it will neither source nor sink current. High-impedance outputs are also commonly referred to as three-state or tri-state outputs. The maximum leakage for the output in this state is defined by I_OZ in the Electrical Characteristics table.

Table 1. Function Table