SBOS831B December 2016 – June 2021 THS4552
PRODUCTION DATA
The bandwidth is controlled to 88 kHz by using the 2.4 nF feedback capacitors. Amplifier stability is controlled by the 20 nF differential capacitor across the DAC outputs. The added 4.4 Ω in series with the feedback 2.2 nF capacitor isolates this capacitance from the inductive open-loop output impedance. To observe the effect of adding these small resistors in series with the feedback capacitors, use the TINA-TI™ loop gain simulation circuit. Include the DAC source capacitance in any final design analysis. Running the frequency response for this circuit (available as a TINA-TI™ simulation file) provides this result. The 63.5 dBΩ gain is the 1.5 kΩ transimpedance gain provided in this design.
Running a full-scale sine wave at 1 kHz with ±1.95 mA on each output from the DAC at 180° out of phase, and probing each THS4552 output pin separately results in the expected ±1.46 V on each output pin, as shown in Figure 9-19. More output swing is available for the RRO device using the ±2.5 V supplies provided by the LM27762 by simply increasing the feedback resistor values.
Although this example is on the audio signal generation side, the THS4552 can also be used to convert a single-ended line input to a differential driver into an audio ADC.