SLASF38A December 2023 – March 2025 TAD5212-Q1
PRODUCTION DATA
All audio data converters require a DC reference voltage. The TAD5212-Q1 achieves low-noise performance by internally generating a low-noise reference voltage. This reference voltage is generated using a band-gap circuit with high PSRR performance. This audio converter reference voltage must be filtered externally using a minimum 1µF capacitor connected from the VREF pin to analog ground (VSS).
The value of this reference voltage can be configured using the P0_R77_D[1:0] register bits and must be set to an appropriate value based on the desired full-scale input for the device (analog bypass path) and the AVDD supply voltage available in the system. The default VREF value is set to 2.75V, which in turn supports a 2VRMS differential full-scale input to the device. The required minimum AVDD voltage for this mode is 3V. Table 6-11 lists the various VREF settings supported along with required AVDD range and the supported full-scale input signal for that configuration.
| P0_R77_D[1:0] : VREF[1:0] | VREF OUTPUT VOLTAGE | DIFFERENTIAL FULL-SCALE INPUT SUPPORTED | SINGLE-ENDED FULL-SCALE INPUT SUPPORTED | AVDD OPERATION MODE |
|---|---|---|---|---|
| 00 (default) | 2.75V | 2VRMS | 1VRMS | AVDD 3.3V Operation |
| 01 | 2.5V | 1.818VRMS | 0.909VRMS | AVDD 3.3V Operation |
| 10 | 1.375V | 1VRMS | 0.5VRMS | AVDD 1.8V Operation |
| 11 | Reserved | Reserved | Reserved | Reserved |
To achieve low-power consumption, this audio reference block is powered down as described in the Section 6.4. When exiting sleep mode, the audio reference block is powered up using the internal fast-charge scheme and the VREF pin settles to a steady-state voltage after the settling time (a function of the decoupling capacitor on the VREF pin). This time is approximately equal to 3.5ms when using a 1μF decoupling capacitor. If a higher-value decoupling capacitor is used on the VREF pin, the fast-charge setting must be reconfigured using the VREF_QCHG (P0_R2_D[4:3]) register bits, which support options of 3.5ms (default), 10ms, 50ms, or 100ms.