Connectors And Sockets; Power Supplies; Reference Circuit - Analog Devices EVAL-AD4858 User Manual

User Guide
EVALUATION BOARD HARDWARE

CONNECTORS AND SOCKETS

The connectors and sockets on the EVAL-AD4858FMCZ are out-
lined in Table 2.
Table 2. On-Board Connectors
Connector Function
SMA0+ to SMA7+ Positive analog input Subminiature Version A (SMA) to
Channel 0 through Channel 7
SMA0− to SMA7− Negative analog input SMA to Channel 0 through Channel 7
P1 FPGA mezzanine card (FMC) connector

POWER SUPPLIES

The ZedBoard supplies 12 V to power the rails for the different
components on the EVAL-AD4858FMCZ. The AD4858 uses the
following five power supply pins:
Positive high voltage power supply (the V
►
Negative high voltage power supply (the V
►
Low voltage power supply (the V
►
1.8 V power supply (the V
►
DDL
Digital power supply (the V
►
IO
A combination of the LT8330 DC/DC converter and the
LDO regulator generate all the needed supply rails on the board.
Table 3. Default Power Supplies Available in the EVAL-AD4858FMCZ
Power Supply (V) Function
+24 V
CC
−24 V
EE
+2.5 V
DDH
+5 V
DD
+1.8 V
IO
analog.com
pin)
CC
pin)
EE
pin)
DD
pin)
pin)
LT1761
Component
LT8330
LT8330
LT1761
LT1761
LT1761

REFERENCE CIRCUIT

By default, the AD4858 in the EVAL-AD4858FMCZ uses the in-
ternal low noise, low drift (10 ppm/°C maximum), temperature
compensated band-gap reference that is factory trimmed to 4.096 V
and the internal reference buffer.
As an optional alternative, an LTC6655
ppm/°C maximum), 4.096 V voltage reference is also provided. This
external reference can be used in two different configurations, as
explained in the AD4858 data sheet and as follows:
External reference with internal buffer. For this configuration,
►
connect the external reference to the REFIO pin and populate
the R62 resistor shown in Figure
External reference with disabled internal buffer. For this configu-
►
ration, connect the external reference to the REFBUF pin and
populate the R46 resistor shown in
REFIO test point to ground.
EVAL-AD4858
high precision, low drift (2
7.
Figure 7 and also connect the
Rev. A | 7 of 11