AN2031 Datasheet, PDF (1/12 Pages) STMicroelectronics – EVALUATION BOARD DESCRIPTION

AN2031
APPLICATION NOTE
STA308-508
EVALUATION BOARD DESCRIPTION
1 DESCRIPTION
The STA308A is a single chip solution for digital audio processing and control in multi-channel
application.
It provides output capabilities for DDX (Direct Digital Amplification). In conjunction with DDX
power device, it provides high quality, high efficiency, all digital amplification.
STA508 is a monolithic quad half bridge stage in Multipower BCD technology. The device can
be used as dual bridge or reconfigured, by connecting CONFIG pin to V_dd pin, as single bridge
with double current capability.
This device is particularly designed to make the Output stage of a stereo DDX amplifier capa-
ble to deliver 80 + 80W @THD = 10% at V_cc = 35V output power on 8Ω load.
In single BTL configuration, is also capable to deliver a peak of 160W@THD = 10% at V_cc =
35V on 4Ω load (t<= 1sec).
2 STA308-508// EVALUATION BOARD DESCRIPTION
In this board it is possible to solder STA308 or STA308A device how digital audio processor.
There are three jumpers (JP2, JP3, JP6) to select the correct device.
The board has one S/PDIF input (electrical single ended and optical).
In this board it is possible to use two different powers (10V to 35V on J2) and logic (5V on J1)
stages or only one supply (10V to 35V on J2) for both stages. This feature is possible setting
JP1 in EXT-SEL or INT-SEL respectively.
U6 and U7 are configured to drive 3 or 2 ohm (over 250W) on the channel.
2.1 SUPPLY VOLTAGE, REGULATORS
The STA308-508// board uses 5V, 3.3V power regulation for logic circuitry and 10<V_cc<35 for
power section of STA508 device.
It is possible to apply only one power supply and to extract the logic power supply utilizing the
L4971D step down device
2.2 S/PDIF INPUT INTERFACE
The STA308A controller's data interface is serial I²S for input.
The STA308-508//-EVB input accommodates coaxial or optical S/PDIF digital audio interfaces
using a digital audio receiver IC. Jumper JP5 may select either input. S/PDIF interfaces
(STA120D) will support sample rates from 32KHz to 96KHz
Optical S/PDIF receiver IC is SHARP GP1F31R.
2.3 DIGITAL SIGNAL PROCESSING
The STA308A converts pulse code modulated, PCM, digital audio input signals into Pulse-
Width Modulated PWM. This signal enters in the same time in the two STA508 ICs and the exit
signal is at high level of power. The STA308A has two independent volume control registers
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