Altera Data Conversion HSMC - Manual (Page 13)

Chapter 2: Board Components and Interfaces 2–7
Component Interfaces
© November 2008 Altera Corporation Data Conversion HSMC Reference Manual
External Clock Output SMA Connectors (J25, J28)
The CLK SMA connector (J25 or J28) provides an external clock output. Different
clocks can be selected by using differential LVDS multiplexer (U13) and clock select
jumper (J23) (
Figure 2–4 ). The external clock source provides (while using a particular
design) the flexibility to alter the input frequency to verify f
MAX
tolerances. If you
choose to use a single-ended clock, R110 must be removed and R109 be installed.
Component Interfaces
This section describes the user interfaces, which consist of the A/D converter, D/A
converter, audio CODEC converter, HSMC connector, and I
2 C Serial EEPROM.
A/D Converter (U1, U2)
The Data Conversion HSMC contains two AD9254 14-bit 150 MS/s A/D converters.
This device is designed for high-speed and high-performance applications.
The inputs to these A/D converters are transformer-coupled in order to create a
balanced input. The signal-to-noise ratio for the system is up to 72 dB for input signals
from 1 MHz to the Nyquist frequency of the converter. The maximum differential
input voltage to the converter is 2 VPP. Usable voltage input to the SMA connector is
approximately 512 mV when driven from a 50-
Ω source.
Table 2–9 lists the A/D converter board reference and manufacturing information.
Figure 2–4. External Clock Output Schematic
External Clock Out
J25 LTI-SASF54GT
XT_CK_OUT_N
J28
5 4 3 2
XT_CK_OUT_P 1
1
Unipolar
XT_CK_OUT_UNI
R110
Bipolar
XT_CK_OUT_BI
4
5
6
T7
3
2
1
ADT1_1WT
P S RX_CLK_P
RX_CLK_N
LTI-SASF54GT
0
R109
0
5 4 3 2
NC
Table 2–9. A/D Converter Component Reference
Board Reference Device Description Manufacturer
Manufacturing
Part Number
Manufacturer
Website
U1, U2 14-bit, 150 MS/s A/D converter Analog Device AD9254 www.analog.com