A/d converters – Altera Stratix II EP2S180 DSP Development Board User Manual

Page 24

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2–16

Core Version a.b.c variable

Altera Corporation

Stratix II EP2S180 DSP Development Board Reference Manual

Board Components

Figure 2–4

shows the pin-outs for the 7-segment display.

Figure 2–4. Pin-Out Diagram for the Dual 7-Segment Display

A/D Converters

The Stratix II EP2S180 DSP development board has two 12-bit A/D
converters that produce samples at a maximum rate of 125 mega-samples
per second (MSPS). The A/D subsystem of the board has the following
features:

The data output format from each A/D converter to the Stratix II
device is in two’s complement format.

The circuit has a wideband, AC-coupled, differential input useful for
IF sampling. The analog inputs are transformer-coupled to the A/D
converter to create a balanced input. To maximize performance, two
transformers are used in series. The Analog Devices data sheet for
the AD9433 device describes the detailed operation of this circuit.

Any required anti-aliasing filtering can be installed externally. If
needed, users can purchase in-line SMA filters from a variety of
manufacturers, such as Mini-Circuits (www.minicircuits.com).

1

The transformer-coupled AC circuit has a lower 3-dB frequency,
of approximately 1 MHz.

The clock signal that drives the A/D converters can originate from the
Stratix II device, the external clock input, or the on-board 100-MHz
oscillator. Jumper J3 controls which clock is used for ADC A and J4 is used

HEX_0A HEX_1A

HEX_0D HEX_0DP HEX_1D HEX_1DP

HEX_0C

HEX_0B

HEX_0E HEX_0F

HEX_0G

HEX_1G

HEX_1C

HEX_1B

HEX_1E H

E

X

_

1F

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