Reset
3.1
Reset
The TLV320DAC3203 internal logic must be initialized to a known condition for proper device function. To
initialize the device in its default operating condition, the hardware reset pin (RESET) must be pulled low
for at least 10ns. For this initialization to work, both the IOVDD and DVdd supplies must be powered up. It
is recommended that while the DVdd supply is being powered up, the RESET pin be pulled low.
The device can also be reset via software reset. Writing '1' into Page 0 / Register 1, Bit D0 resets the
device. After a device reset, all registers are initialized with default values as listed in the Register Map
section
3.2
Device Startup Lockout Times
After the TLV320DAC3203 is initialized through hardware reset at power-up or software reset, the internal
registers are initialized to default values. This initialization takes place within 1ms after pulling the RESET
signal high. During this initialization phase, no register-read or register-write operation should be
performed on ADC or DAC coefficient buffers. Also, no block within the codec should be powered up
during the initialization phase.
3.3
Analog and Reference Startup
The TLV320DAC3203 uses an external REF pin for decoupling the reference voltage used for the data
converters and other analog blocks. REF pin requires a minimum 1uF decoupling capacitor from REF to
AVss. In order for any analog block to be powered up, the Analog Reference block must be powered up.
By default, the Analog Reference block will implicitly be powered up whenever any analog block is
powered up, or it can be powered up independently. Detailed descriptions of Analog Reference including
fast power-up options are provided in . During the time that the reference block is not completely powered
up, subsequent requests for powering up analog blocks (e.g., PLL) are queued, and executed after the
reference power up is complete.
3.4
PLL Startup
Whenever the PLL is powered up, a startup delay of approx 10ms is involved after the power up
command of the PLL and before the clocks are available to the codec. This delay is to ensure stable
operation of PLL and clock-divider logic.
3.5
Setting Device Common Mode Voltage
The TLV320DAC3203 allows the user to set the common mode voltage for analog inputs to 0.75V or 0.9V
by programming Page 1, Register 10, D(6). The input common-mode voltage of 0.9V works best when the
analog supply voltage is centered around 1.8V or above, and offers the highest possible performance. For
analog supply voltages below 1.8V, a common mode voltage of 0.75V must be used.
Table 3-1. Input Common Mode voltage and Input Signal Swing
Input Common Mode
AVdd (V)
Channel Gain (dB)
Single-Ended Input
Differential Input
Voltage (V)
Swing for 0dBFS
Swing for 0dBFS
output signal (V
RMS
)
output signal (V
RMS
)
0.75
>1.5
–2
0.375
0.75
0.90
1.8 … 1.95
0
0.5
1.0
NOTE:
The input common mode setting is common for DAC playback and Analog Bypass path
73
SLAU434 – May 2012
Device Initialization
Copyright © 2012, Texas Instruments Incorporated