Texas Instruments Explore DSD1796, PCM1796, and PCM1798: Functional Overview and Key Features

Functional Block Diagram www.ti.com

1.1Functional Block Diagram

Figure 1-1illustrates the functional block diagram of the DEM-DSD1796/PCM1795/PCM1796/PCM1798 EVM.

		I/V
	CN003	5534a
	Serial		BAL￿Amp	LchOUT
	Connector
			5534a	(4.5￿VRMS)
		I/V
		5534a
S/PDIF￿IN		DSDS1796
	DAI	PCM1795
OPT
	CS8414	PCM1796
Coax
		PCM1798
		I/V
		5534a
			BAL￿Amp	RchOUT
	SW001−003		5534a	(4.5￿VRMS)
	Mode￿Control	I/V
		5534a
		DEM-AS/CDAC￿Daughter￿Card
		3.3-V
		Regulator
		+VCC	±AVCC
		(5￿V)	(±15￿V)
	Figure 1-1. DEM-DSD1796/PCM1795/PCM1796/PCM1798 Block Diagram

1.2EVM Features

The DEM-DSD1796/PCM1795/PCM1796/PCM1798 series of stereo DACs consist of a DAI (S/PDIF) section that uses a DSD1796/PCM1795/PCM1796/PCM1798 DAC section, a differential current/voltage (I/V) section, and a balanced amplifier with a post-low-pass filter (LPF) section.

The DEM-DSD1796/PCM1795/PCM1796/PCM1798 requires a 5-V digital power supply for its digital circuits, a 5-V analog power supply for the device itself, and a ±15-V analog power supply for the balanced amplifier circuits.

The DAI section has both coaxial and optical inputs that are switch-selectable and capable of handling sampling rates up to 96 kHz.

The DSD1796/PCM1795/PCM1796/PCM1798 accepts PCM audio data input at a sampling rate up to 192

kHz, or a 64-fSDSD signal input, as determined by functional control settings and jumper connections on the board.

This evaluation fixture uses the DEM-DSD1796/PCM1795/PCM1796/PCM1798 demonstration board and demonstration software for functional evaluation and operational control of the DSD1796/PCM1795/PCM1796/PCM1798 DAC device.

8 Description SLEU057A–September 2004–Revised May 2009

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