AT32UC3B1256-AUR Atmel, AT32UC3B1256-AUR Datasheet - Page 572

• Manufacturer Part Number: AT32UC3B1256-AUR
• Description: MCU AVR32 256K FLASH 48-TQFP
• Manufacturer: Atmel
• Series: AVR®32 UC3r

Specifications of AT32UC3B1256-AUR

• Package / Case: 48-TQFP, 48-VQFP
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Operating Temperature: -40°C ~ 85°C
• Speed: 60MHz
• Number Of I /o: 28
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 32K x 8
• Program Memory Size: 256KB (256K x 8)
• Data Converters: A/D 6x10b
• Oscillator Type: Internal
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Connectivity: I²C, IrDA, SPI, SSC, UART/USART, USB
• Core Size: 32-Bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

26. Audio Bitstream DAC (ABDAC)
26.1
26.2
32059J–12/2010
Features
Overview
Rev: 1.0.1.1
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The Audio Bitstream DAC converts a 16-bit sample value to a digital bitstream with an average
value proportional to the sample value. Two channels are supported, making the Audio Bit-
stream DAC particularly suitable for stereo audio. Each channel has a pair of complementary
digital outputs, DATAn and DATANn, which can be connected to an external high input imped-
ance amplifier.
The output DATAn and DATANn should be as ideal as possible before filtering, to achieve the
best SNR and THD quality. The outputs can be connected to a class D amplifier output stage to
drive a speaker directly, or it can be low pass filtered and connected to a high input impedance
amplifier. A simple 1st order low pass filter that filters all the frequencies above 50kHz should be
adequate when applying the signal to a speaker or a bandlimited amplifier, as the speaker or
amplifier will act as a filter and remove high frequency components from the signal. In some
cases high frequency components might be folded down into the audible range, and in that case
a higher order filter is required. For performance measurements on digital equipment a minimum
of 4th order low pass filter should be used. This is to prevent aliasing in the measurements.
For the best performance when not using a class D amplifier approach, the two outputs DATAn
and DATANn, should be applied to a differential stage amplifier, as this will increase the SNR
and THD.
Digital Stereo DAC
Oversampled D/A conversion architecture
Digital bitstream outputs
Parallel interface
Connected to DMA Controller for background transfer without CPU intervention
– Oversampling ratio fixed 128x
– FIR equalization filter
– Digital interpolation filter: Comb4
– 3rd Order Sigma-Delta D/A converters
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