JAJSO54 November 2022 TPA3223
PRODUCTION DATA
The gain of TPA3223 is set by the voltage divider connected to the GAIN/CLKSYNC control pin. Clock synchronization configuration is also controlled by the same pin. An internal ADC is used to detect the 8 input states. The first four stages sets the GAIN in Primary mode in gains of 20, 23.5, 32 and 36 dB respectively, while the next four stages sets the GAIN in peripheral mode in gains of 20, 23.5, 32 and 36 dB respectively. The gain setting is latched when RESET goes high and cannot be changed while RESET is high. Table 9-1 shows the recommended resistor values, the state and gain:
Primary / Peripheral Mode | Gain | R1 (to GND) | R2 (to AVDD) | Differential Input
Signal Level (each input pin) |
Single Ended Input Signal Level |
---|---|---|---|---|---|
Primary | 20 dB | 5.6 kΩ | OPEN | 2 VRMS | 2 VRMS |
Primary | 23.5 dB | 20 kΩ | 100 kΩ | 1 VRMS | 2 VRMS |
Primary | 32 dB | 39 kΩ | 100 kΩ | 0.5 VRMS | 1 VRMS |
Primary | 36 dB | 47 kΩ | 75 kΩ | 0.32 VRMS | 0.63 VRMS |
Peripheral | 20 dB | 51 kΩ | 51 kΩ | 2 VRMS | 2 VRMS |
Peripheral | 23.5 dB | 75 kΩ | 47 kΩ | 1 VRMS | 2 VRMS |
Peripheral | 32 dB | 100 kΩ | 39 kΩ | 0.5 VRMS | 1 VRMS |
Peripheral | 36 dB | 100 kΩ | 16 kΩ | 0.32 VRMS | 0.63 VRMS |
For easy multi-channel system design TPA3223 has a Clock Synchronization feature that allows automatic synchronization of multiple peripheral devices operated at the PWM switching frequency of a Primary device. Using clock synchronization benefits system noise performance by eliminating spurious crosstalk sum and difference tones due to unsynchronized channel-to-channel switching frequencies. Furthermore, the Clock Synchronization scheme is designed to interleave switching of the individual channels in a multi-channel system such that the power supply current ripple frequency is moved to a higher frequency, which reduces the RMS ripple current in the power supply bulk capacitors.
The Clock Synchronization scheme and the interleaving of the output stage switching are automatically configured by connecting the OSCx pins between a Primary and multiple peripheral devices. There are two different configurations of peripheral devices (secondary or tertiary) depending on how the OSCx pins are connected. Connect the OSCM of the Primary device to the OSCM of a peripheral device and the OSCP of the Primary device to the OSCP pin of a peripheral device to configure as a secondary. Connect the OSCM of the Primary device to the OSCP of a peripheral device and the OSCP of the Primary device to the OSCM pin of a peripheral device to configure as a tertiary. The Primary, secondary and tertiary PWM switching is 30 degrees out of phase with each other. All switching channels are automatically synchronized by releasing RESET on all devices at the same time.
Placement on the PCB and connection of multiple TPA3223 devices in a multi channel system is illustrated in Figure 9-6. Peripheral devices must be placed on either side of the Primary device, with a secondary device on one side of the Primary device, and a tertiary device on the other. In systems with more than 3 TPA3223 devices, the Primary must be in the middle, and every second peripheral device must be a secondary or tertiary as illustrated in Figure 9-6. A 47 kΩ pull up resistor to AVDD must be connected to the Primary device OSCM output and a 47 kΩ pull down resistor to GND must be connected to the Primary OSCP CLK outputs.