8.1.9 Pulse Application With Single-Supply Circuit

For pulsed applications where the signal is at ground and pulses to a positive or negative voltage, the circuit bias-voltage considerations differ from those in an application with a signal that swings symmetrically around a reference point. Figure 80 shows a circuit where the signal is at ground (0 V) and pulses to a positive value. The waveforms are shown slightly above ground because the output stage requires approximately 100 mV headroom to the supplies. To operate with the I/O swing truly to ground on a single-supply setup, consider using the fixed –0.23-V output LM7705.

Figure 80. Noninverting Single-Supply Circuit With Pulse

As shown in Figure 81, an inverting amplifier is more appropriate if the input signal pulses negative from ground. A key consideration in noninverting and inverting cases is that the input and output voltages are kept within the limits of the amplifier. Because the V_ICR of the OPA837 includes the negative supply rail, the OPA837 op amp is well-suited for this application.

Figure 81. Inverting Single-Supply Circuit With Pulse