UG-261 Datasheet, PDF (7/8 Pages) Analog Devices – The EVAL-INAMP-62RZ is designed for evaluation

Evaluation Board User Guide
UG-261
QUICK START FOR THE EVAL-INAMP-82RZ AND EVAL-INAMP-82RMZ BOARDS
The quick start instructions in this section assume that the
evaluation board is in default condition as shown in Table 7.
This section describes two separate evaluation boards, where
the EVAL-INAMP-82RZ has an SOIC footprint and the
EVAL-INAMP-82RMZ has an MSOP footprint.
Table 7. Factory Setting
Connection
W1 is soldered.
Purpose
REF is tied to ground.
Follow Step 1 through Step 3 to get started using these boards
(see Figure 4).
1. Connect a ±2.3 V to ±15 V supply to +VS and −VS. (Consult
the specific data sheet for power supply operating range.)
2. Drive the inputs with a signal.
3. Measure the output on a multimeter or oscilloscope. The
output voltage is the voltage measured between VOUT (OUT)
and VREF (REF). The output can drive another device, such
as an ADC.
+V_S
0.1µF 10µF
+IN
+IN 4
8 +V_S
R_G 3 ⁺
R1
DUT
SMA/SMB
CONNECTOR
7 V_OUT ^{OUT (OPTIONAL)}
R_G 2
–
6 V_REF
–IN
–IN 1
5 –V_S REF
W1
10µF 0.1µF
–V_S
Figure 4. EVAL-INAMP-82RZ Schematic
REFERENCE
The reference level of the instrumentation amplifier can be set
by driving the REF pin with a precision voltage reference or by
using the solder jumper, W1. By default, W1 is soldered, shunting
REF to ground. If a reference voltage other than ground is used,
the solder must be removed from W1 before driving REF with
the reference voltage, as shown in Figure 5.
+V_S
OSCILLOSCOPE
+IN
1V p-p, 1kHz
–IN
5V
10V
0.1µF 10µF
+
DUT
–
W1
OUT
REF
5V
+ COM
10µF 0.1µF
0V –V_S
Do not leave the in-amp inputs floating, that is, without a dc
return path. This often occurs when the inputs are connected to
a transformer, a thermocouple, or a pair of series capacitors.
The inputs should have a dc path to ground, as shown in Figure 5
and Figure 6.
The circuit shown in Figure 6 has series capacitors, C1 and C2,
between the signal generator and the input. The series capacitors
prevent a dc current from flowing into the input transistors of
the instrumentation amplifier. Two matched 10 kΩ resistors are
used between the instrumentation amplifier inputs and ground
to provide the necessary current path. Closely match these
resistors to reduce offset and CMRR errors.
OSCILLOSCOPE
+V_S
C1 _+IN
C2 _–IN
10kΩ
+15V
0.1µF 10µF
R1
499Ω
10kΩ
+
DUT
–
W1
OUT
REF
+ COM
10µF 0.1µF
–15V
–V_S
Figure 6. AC Input Coupling Using a Resistive DC Return Path
OUTPUT
Output measurements should be made by monitoring the voltage
between the OUT and REF tie points of the board, as shown in
Figure 7. If an external voltage reference is used, the output can
be measured, referred to ground, as shown in Figure 5. The
evaluation board offers an SMA/SMB outline. By default, the
output voltage measured using an SMA/SMB connector is with
respect to ground.
+V_S
OSCILLOSCOPE
+15V
0.1µF 10µF
+IN
+ COM
500mV p-p,
100Hz
10V p-p,
10Hz
R1
5.49kΩ
–IN
+
DUT
–
W1
OUT
REF
10µF 0.1µF
–15V
–V_S
Figure 7. Correct Output Connection Using the REF Pin
Figure 5. Using an External Voltage Source to Set the
Reference Level (Circled) Input
Rev. C | Page 7 of 8