EVAL-CN0209-SDPZ Analog Devices Inc, EVAL-CN0209-SDPZ Datasheet - Page 3

• Manufacturer Part Number: EVAL-CN0209-SDPZ
• Description: EVAL CIRCUIT BOARD
• Manufacturer: Analog Devices Inc
• Series: -r

Specifications of EVAL-CN0209-SDPZ

• Main Purpose: Interface, Analog Front End (AFE)
• Embedded: No
• Utilized Ic / Part: AD7193, AD8275, AD8617, AD8676, ADG1414, ADG442, ADP1720, ADT7310, ADuM1400, ADuM1401, REF194
• Primary Attributes: -
• Secondary Attributes: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Circuit Note
available on the board. The resistor configuring the current
source must have a low temperature coefficient to avoid drift
errors in the measurement circuit.
Thermocouple Measurement
In a thermocouple application, the voltage generated by the
thermocouple is measured with respect to an absolute
reference, provided externally to the ADC. The cold junction
compensation is implemented using the
temperature sensor. Because the signal from the thermocouple
is small, and to maximize the dynamic range in the circuit, the
AD7193 is operated at its highest gain range of 128. Because the
input channel is buffered, large decoupling capacitors can be
placed on the front end, if required, to eliminate any noise
pickup that may be present in the thermocouple leads. The
common-mode voltage for the thermocouple measurement is
provided by the AD8617 amplifier.
4 mA-to-20 mA Current Measurement
This circuit also supports 4 mA-to-20 mA current
measurement. The current is converted to a voltage using an
on-board sense resistor. To use the full dynamic range of the
ADC in the current measurement mode, a 200 Ω resistor is used.
JX-2
JX-1 JX-2
RTD 2 WIRES
JX-3
RTD
TC
JX-3
JX-3
TC
JX-4
JX-4
ADT7310
Figure 2. Analog Input Configuration Table
16-bit
DIFFERENTIAL INPUT VOLTAGE
JX-2
CURRENT INPUIT
Va
CONNECTION TABLE
JX-1 JX-2
JX-3
JX-5
Rev. 0 | Page 3 of 5
RTD 3 WIRES
Vb
CURRENT
RTD
Uab = Va–Vb
JX-6
JX-3 JX-4
The sense resistor must have a low temperature coefficient
to avoid temperature drift errors in the measurement
circuit.
Regulator and Reference Selection
The
The ADP1720 is a high voltage micropower linear regulator
particularly suitable for industrial application.
The 4.5 V
and the E-grade device has an initial accuracy ±2 mV at 25°C
and a drift of 5 ppm/°C maximum. It is a low dropout device
and consumes less than 45 μA, with performance specifications
over −40°C to +125°C.
Isolation
The
isolators based on Analog Devices’ iCoupler® technology. These
are used to provide isolation between the field side and the
system microcontroller, with an isolation rating of 2.5 kV rms.
Four wires are used through the ADuM1400, all for transmit
(SCLK, DIN, ADG1414 , ADT7310 ). Four wires are used
through the ADuM1401: one for transmit ( AD7193 ) and three
for receive (INT1, INT2, DOUT). The DIN, DOUT, and SCLK
lines are connected to the SPORT interface.
ADP1720
ADuM1400
REF194
was chosen as the 5 V regulator for this circuit.
and the
SINGLE INPUT VOLTAGE
JX-1 JX-2
was chosen as the reference for this circuit,
JX-2
RTD 4 WIRES
V
ADuM1401
RTD
JX-3
JX-3 JX-4
are quad-channel digital
CN-0209