5962-9756301HXC View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'5962-9756301HXC' PDF : 16 Pages View PDF
AD9070
AD9070BR EVALUATION BOARD
E2
E1
AD780 REFERENCE
1k⍀
AIN
50⍀
1k⍀
–5V
E3
VREF OUT
VREF IN
COMP
BYPASS
AIN
AIN AD9070
1 OF 2
10H176 TO CARD
HEX D FF CONNECT
1 OF 4
10H116
CLK
J2
50⍀
10H176
ECL
RECVR
ENC ENC
E19
CLKB
J4
E8 E9
50⍀
E4 E6
BUFFERED
AND
LATCHED
ON-CARD
ENCODE E7
E5
PIN 2
CARD
CONNECTOR
PIN 21
Figure 13.
The AD9070 evaluation board is a convenient and easy way to
evaluate the performance of the AD9070 in the SOIC package.
The board consists of an AD780 voltage reference (configured
for –2.5 V), two 10H176 (hex D flip flop) for capturing data
from the A/D converter and five 10H116 triple line receivers for
buffering the encode signal and driving the data via the edge
connector. Termination resistors (RP11, RP12, and RP14) are
provided for the data leaving the board via the connector; (they
can be removed if termination resistors are already provided by
the user).
Analog Input
The evaluation board requires a 1 V peak-to-peak signal centered
at ground (J1). This signal is ac-coupled and then dc shifted
–2.5 V before it is input to the A/D converter.
Encode
The AD9070 encode inputs can be driven single-ended (connect
E9 to E19 and drive J2 with an ECL signal) or differentially
(connect E8 to E19 and drive J2 and J4 with differential ECL
signals). The board is shipped in single ended configuration. The
differential encode signal leaving the board via the connector
can be inverted by interchanging E4, E5, E6, and E7 (connect
E4 to E7 and E5 to E6 or E4 to E6 and E7 to E5). This ensures
that the user will be able to capture the data coming from the
evaluation board.
Data Out
Data goes single-ended into the 10H116 flip flops but comes
out differentially. The data coming out of the AD9070 is in
two’s complement format, but is changed to straight binary by
inverting the MSB at the connector (on the schematic Bit 1 and
Bit 1B are swapped).
Voltage Reference
The AD9070 can be operated using its internal bandgap reference
(connect E2 to E3) or the on board AD780 external reference
(connect E1 to E3). The board is shipped utilizing the internal
voltage reference.
Layout
The AD9070 is not layout-sensitive if some important guidelines
are met. The evaluation board layout provides an example where
these guidelines have been followed to optimize performance.
• Provide a good ground plane connecting the analog and
digital sections.
• Excellent bypassing is essential. Chip caps with 0.1 µF values
and 0603 dimensions are placed flush against the pins. Placing
any of the caps on the bottom of the board can degrade
performance. These techniques reduce the amount of parasitic
inductance which can impact the bypassing ability of the caps.
• Separate power planes and supplies for the analog and digital
sections are recommended.
The AD9070 evaluation board is provided as a design example
for customers of Analog Devices. ADI makes no warranties
express, statutory, or implied regarding merchantability or
fitness for a particular purpose.
–12–
REV. C
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