AnsweredAssumed Answered

STA326 power supply, programming sequence and output filter

Question asked by Øyvind Aabling on Jun 24, 2017

The STA326 datasheet (DocID11531 Rev 9) is unclear on a couple of points, so:

 

* Does the STA326 output power level depend on the output stage supply voltage (VCC[12][AB] on pins 4,8,11,15),

or does it depend only on the digital signal chain (digital input signal and volume and effects settings) ?

The output clipping level will of course depend on the supply voltage, so obviously I'm talking about power levels below clipping :-)

 

* What are the frequency limits of the XTI/CLK pin (pin 27) ?

 

* Is there a required or recommended sequence for changing the input signal format and/or frequency ?

 

In the CLK/XTI pin (pin 27) section on page 12 of the Datasheet, it says:

"Care must be taken to provide the device with the nominal system clock frequency;

over-clocking the device may result in anomalous operation, such as inability to communicate.".

 

So, when switching between formats, e.g. 16-bit 44.1 kHz, 48, 96 or 192 kHz (24-bit),

in which order must these values and signals be changed:
* LR clock input (pin 31),
* Bit clock input (pin 32),
* XTI clock input (pin 27, also referred to CLK),
* Bits 0-4 in Conf Reg A (MCS# and IR#),
* Bits 0-4 in Conf Reg B (SAI# and SAIFB) ?

 

When switching signal family (44.1 vs. N*48 kHz), the XTI/CLK pin must be switched between e.g. 11.2896 MHz and 12.288 MHz.
Is that variation within the overclocking limit ?

How will the STA326 react to a (short) removal of the XTI clock (while switching between oscillators) ?

What happens when the XTI clock and LR/BIT clocks don't match during the switchover

- should the input signal (LR+BIT clocks) maybe be stopped during the switch ?

 

* Are there any app notes available for the STA326, e.g. output filter component and board layout recommendations ?

I'm especially interested in recommendations about how to choose the output filter components.

Is there a BOM available for the Drum reference board (for inspiration, I'm interested in the output filter components only) ?

Outcomes