Evaluation Board Hardware; Setting Up The Evaluation Board; Power Supplies; Reference, Reference Buffer, And Common-Mode Buffer - Analog Devices EVAL-AD4001FMCZ User Manual

UG-1042 Easy to Use AD4000 Series 16-/18-/20-Bit Precision SAR ADCs User Guide

EVALUATION BOARD HARDWARE

(OPTIONAL)
–V
GND
+V
(OPTIONAL)
VDD
GND
VREF
ADA4807-1
VIN+
ADA4807-1
VIN–

SETTING UP THE EVALUATION BOARD

Figure 2 shows the simplified evaluation board block diagram.
Figure 25 shows the evaluation board schematic. The board
consists of the ADC, U1, with a reference, U6 (ADR4550), and
ADC drivers, U12 and U14, the
AD4002/AD4003/AD4020 and the
(see Table 5). The user also has an option to populate U2 with a
low power, fully differential ADC driver such as the ADA4940-1
when evaluating the AD4001/AD4003/AD4020. The evaluation
board is a flexible design that enables the user to select components
in addition to operating from an adjustable bench top power
supply.

POWER SUPPLIES

The system demonstration platform (SDP-H1) board supplies
12 V to power the necessary rails for the AD4000/AD4001/
AD4002/AD4003/AD4020 evaluation board.
Table 1. Power Supplies Provided on the Board
Power Supply (V) Function
1
5, 7 (default) Positive rail
1
−5, −2.5 (default) Negative rail
1.8 ADC power
3.3 V (digital power)
DRIVE
1
See Table 2.
S
POWER SUPPLY CIRCUITRY
ADP7118, ADP2370, ADM660, ADP7182
+7V/+5V/–2.5 +1.8V
S
VCM
ADA4807-1
ADA4807-1
+7V
VDD REF
AD4000/
IN+
–2.5V
AD4001/
AD4002/
+7V
AD4003/
IN–
AD4020
A B
GND
–2.5V
EASY TO USE AD4000 SERIES 16-BIT/18-BIT/20-BIT
PRECISION SAR ADCs EVALUATION BOARD
Figure 2. Simplified Evaluation Board Block Diagram
ADA4807-1 for the AD4001/
ADA4805-1 for the AD4000
Components Used
ADP7118
ADP2370, ADM660,
ADP7182
ADP7118, ADP5300
ADP7118
+7V +3.3V
12V
ADR4550
5V
VIO
SDI
SCK
SDO
CNV
SPI
INTERFACE
120-PIN
CONNECTOR
The 7 V amplifier positive rail (+V
ADP7118). The −2.5 V negative amplifier rail (−V
by a combination of U3 (the ADP2370), U7 (the ADM660), and
U21 (the ADP7182).
Each supply is decoupled where it enters the board and again at
each device. A single ground plane is used on this board to
minimize the effect of high frequency noise interference.
In addition, there is also the ability to power the board from a
bench top power supply. The screw terminals, J2 and J3, are
provided for this function. When bench power is used, the on-
board power supplies are no longer required. The solder links also
must be changed: SL1 = SL2 = SL5 = SL6 = SL7 = SL8 = SL9 = B.
REFERENCE, REFERENCE BUFFER, AND COMMON-
MODE BUFFER
An external 5 V reference (U6, ADR4550) is used by default to
supply the ADCs directly. However, the user can also use one of
the 2.5 V, 3.3 V, and 4.096 V references by changing the reference
device on the board (U6, ADR4525/ADR4533/ADR4540). There is
also an option to use a lower power reference (U22, ADR3450).
Note that the ADR3450
The ADA4807-1
mode buffer (U18) by default. However, it can also be replaced by
the AD8031 if needed without compromising the performance.
Rev. E | Page 4 of 25
12V
WALL WART
12V
USB PORT
POWER
SUPPLY
CIRCUITRY
SPARTAN-6
ADSP-BF527
FPGA
XC6SLX25
EVAL-SDP-CH1Z
) is generated from U17 (the
S
cannot accept input voltages beyond 5.5 V.
is used as a reference buffer (U16) and common-
) is generated
S