Serial Interface; Analog Inputs - Analog Devices EVAL-AD7625FMCZ User Manual

EVAL-AD7625FMCZ/EVAL-AD7626FMCZ User Guide
Table 3. On-Board Power Supplies Description
Power Supply Voltage Range (V)
+V 5 to 7
S
−V −2 to −5
S
|+V to −V | 12
S S
VDD1 5
VDD2, VIO 2.5
1 Dictated by ADA4899-1 supply operation.
Refer to the AD7625 and AD7626
2

SERIAL INTERFACE

The EVAL-AD7625FMCZ/EVAL-AD7626FMCZ
boards use the serial interface connection to the
CH1Z SDP board. The evaluation boards operate only in echo-
clocked serial interface mode. This mode requires three LVDS
pairs (D±, CLK±, and DCO±) between the
and the digital host. The SDP board features include
•
XILINX Spartan®-6 FPGA
•
DDR2
Micron MT47H32M16Hr-25E:G
•
8 Mb × 16 bits × 4 Banks(512 Mb/64 Mb)
•
SRAM
ISSI IS61WV25616BLL-10BLI
•
256 kB × 16 bits (4 Mb/512 kB)
•
1 × 160-pin FMC-LPC connector (refer to the VITA 57
specification)
Samtec ASP-134603-01
•
Up to 1080 Mbps LVDS
•
Single-ended LVCMOS
•
Power
•
•
Analog Devices ADSP-BF527
Core performance up to 600 MHz
•
208-ball CSP-BGA package
•
24 MHz CLKIN oscillator
•
•
32 Mb flash memory
Numonyx M29W320EB or Numonyx M25P32
•
•
SDRAM memory
Micron MT48LC16M16A2P-6A
•
16 Mb × 16 bits (256 Mb/32 MB)
•
2 × 120-pin small footprint connectors
Hirose FX8-120P-SV1(91), 120-pin header
•
•
Blackfin processor peripherals exposed
SPI
•
SPORT
•
TWI/I C
• 2
GPIO
•
PPI
•
Asynchronous parallel
•
Description
The ADP7104 (U10) and
from the 12 V supply coming from the EVAL-SDP-CH1Z. The 7 V supply is recommended for the on-
board amplifier +V
S
the ADP2300 (U5), and the
bench top supply +V
The ADP2300 generates −2.5 V for amplifier −V
top supply −V through J4.
S
Maximum range of supply for correct operation.
AD7625/AD7626 analog supply rail.
ADC supply rails. 2
data sheets.
evaluation
EVAL-SDP-
AD7625/AD7626
Blackfin® processor
ADP7102 (U18) generate the necessary 5 V and 7 V supplies, respectively,
. The 5 V supply is provided to VDD1 (U1), the external reference
ADP124 (U12 and U16). The user also has an option to use an external
through J4.
S
. The user also has an option to use an external bench
S
1
2

ANALOG INPUTS

The analog inputs applied to the
AD7626FMCZ
These inputs are buffered with dedicated discrete driver amplifier
circuitry (U13 and U15 or U6), as shown in Figure 1.
The circuit allows different configurations, input range scaling,
filtering, the addition of a dc component, the use of a different
op amp, and a differential amplifier and supplies. The analog
input amplifiers are set as unity-gain buffers at the factory. The
driver amplifiers (U6, U13, and U15) positive rails are driven
from 7 V (from ADP7102, U18), and the negative rail is driven
from −2.5 V. The positive rails of the other reference buffers
(U8 and U11) are driven from 7 V, and the negative rails are
grounded. Change these values as required.
Table 3 lists the range of possible supplies. The default
configuration sets both U13 and U15 at midscale generated
from a buffered reference voltage (VCM) of the AD7625/
AD7626 (U1). The evaluation board is factory configured to
provide either a single-ended path or a fully differential path,
as described in Table 1.
For dynamic performance, a fast Fourier transform (FFT) test
can be performed by applying a very low distortion source.
For low frequency testing, the audio precision source can be
used directly, because the outputs on these are isolated. Set the
outputs for balanced and floating. Different sources can be
used, though most are single ended and use a fixed output
resistance.
Because the evaluation board uses the amplifiers in unity gain,
the noninverting input has a common-mode input with a series
1 kΩ resistor, which must be taken into account when directly
connecting a source (voltage divider).
Rev. A | Page 5 of 28
EVAL-AD7625FMCZ/EVAL-
are the J3 and J5 SMA (push-on) connectors.
UG-745
ADR3412 (U14),