TAS6421-Q1 Automotive Burr-Brown™ Audio Amplifiers Texas Instruments TAS6421-Q1 Automotive Class-D Burr-Brown™ Audio Amplifiers implement a 2.1MHz PWM switching frequency, enabling a cost-optimized solution for a tiny PCB size. The TAS6421-Q1 features full operation down to 4.5V for start/stop events and exceptional sound quality with up to 40kHz audio bandwidth.