DSP-DEVKIT-2S60 Altera, DSP-DEVKIT-2S60 Datasheet - Page 23

• Manufacturer Part Number: DSP-DEVKIT-2S60
• Manufacturer: Altera

Specifications of DSP-DEVKIT-2S60

• Lead Free Status / Rohs Status: Not Compliant

Board Components & Interfaces
Altera Corporation
August 2006
D/A Converters
The Stratix II DSP development board has two D/A converters. The D/A
subsystem of the board has the following features:
■
■
1
The D/A clock signals are output directly from the Stratix II device to the
converters.
Figure 4
of a D/A converter chip, DAC904, consists of a current source whose
maximum value is 20 mA. This differential output is converted to a single
-ended output using an RF transformer The DSP board uses a 1:1 ratio
transformer to interface to a 50 ohm impedance load. Each of the outputs
is terminated with a 49.9 ohm resistor to ground. This circuit results in
outputs being AC coupled and inherently isolated due to transformer’s
magnetic coupling. The output of the transformer is then brought to an
SMA connector.
Figure 4. On-Board Circuitry after D/A Converter
1
The converters produce 14-bit samples at a maximum rate of 165
MSPS
The analog output from each D/A converter is single-ended
shows the on-board circuitry after a D/A converter. The output
The D/A converters expect data in an unsigned integer format.
The development kit includes an SLP-50 anti-aliasing filter from
Mini-Circuits. This filter provides a 55-MHz cut-off frequency.
For systems with other bandwidth requirements, a variety of
anti-aliasing filters are available from commercial
manufacturers to suit the system requirements.
Reference Manual
Stratix II Development Board
2–13