Datasheet

Evaluation Board User Guide UG-080
Rev. 0 | Page 3 of 12
EVALUATION BOARD HARDWARE
POWER SUPPLIES
The AD7170 evaluation board is powered via the 5 V supply
from the USB connector, J51. This 5 V supply can be used to
power the AD7170 directly. A 3.3 V regulated voltage from the
on-board ADP3330 (a high precision, low power, 3.3 V output
voltage regulator) can also be used. Alternatively, the AD7170 can
be powered using an external 3 V or 5 V power supply via J6.
LINKS
There are four groups of link options that must be set for the
required operating setup before using the evaluation board. The
functions of these link options are outlined in Table 1.
SETUP CONDITIONS
Care should be taken before applying power and signals to the
evaluation board to ensure that all link positions are set per the
required operating mode. Table 2 shows the position in which
all the links are initially set.
SOCKETS
Three sockets are relevant to the operation of the AD7170 on
this evaluation board. The functions of these sockets are
outlined in Table 3.
Table 1. Evaluation Board Link Settings
Table 2. Initial Link and Switch Positions
Link Position Function
J3, J7 IN AIN(+) and AIN(−) are shorted to AVDD/2.
J8, AGND AVDD, IN The reference voltage is set to 3.3 V (AVDD).
J1 3.3 V The 3.3 V supply is used as AV
DD
for the AD7170.
J2 IN The AD7170 is interfaced to the on-board microcontroller.
Table 3. Socket Functions
Link Default Description
J3, J7 IN
These links are used to connect the AIN(+) and AIN(−) inputs to AV
DD
/2. With this configuration, a noise analysis
can be performed. With these links removed, an external voltage can be applied to AIN using J4.
J8, AGND AVDD, IN
AVDD can be used as the reference for the AD7170. With J8 in Position AVDD and Link AGND inserted, AVDD is
connected to REFIN(+), and REFIN(−) is connected to AGND. With J8 in Position REF and Link AGND inserted,
REFIN(+) is connected to the ADR391 (2.5 V), and REFIN(−) is connected to AGND. To use another reference
source, remove the J8 and AGND links.
J1 3.3 V
J1 is used to select the power source for AV
DD
on the AD7170. J1 in Position 3.3 V selects the 3.3 V regulated
output from the onboard ADP3330 voltage regulator. J1 in Position 5 V selects the 5 V supply from the USB
connector, J51. J1 in Position EXT selects an external power supply, supplied via J6.
J2 IN
These links connect the AD7170 serial interface pins to the SPI interface of the microcontroller. The links should
be in place to use the AD7170 evaluation board software. With these links removed, the AD7170 can be
interfaced to an external microcontroller.
Socket Description
J4
2-lead terminal block. An external analog signal can be connected to the analog input pins of the AD7170 using this
terminal block.
J5
2-lead terminal block. An external reference source can be connected to the analog input pins of the AD7170 using this
terminal block.
J6 2-lead terminal block. An external power supply can be used to supply the AD7170 using this terminal block.