AD8226ARZ Analog Devices Inc, AD8226ARZ Datasheet - Page 21

• Manufacturer Part Number: AD8226ARZ
• Description: Precision InAmp
• Manufacturer: Analog Devices Inc

Specifications of AD8226ARZ

• Amplifier Type: Instrumentation
• Number Of Circuits: 1
• Output Type: Rail-to-Rail
• Slew Rate: 0.6 V/µs
• -3db Bandwidth: 1.5MHz
• Current - Input Bias: 20nA
• Voltage - Input Offset: 200µV
• Current - Supply: 350µA
• Current - Output / Channel: 13mA
• Voltage - Supply, Single/dual (±): 2.2 V ~ 36 V, ±1.35 V ~ 18 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• No. Of Amplifiers: 1
• Input Offset Voltage: 200µV
• Bandwidth: 1.5MHz
• Amplifier Output: Rail To Rail
• Cmrr: 80dB
• Supply Voltage Range: ± 1.35V To ± 18V
• Supply Current: 350µA
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Gain Bandwidth Product: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Common-Mode Rejection Ratio Over Frequency
Poor layout can cause some of the common-mode signals to be
converted to differential signals before reaching the in-amp.
Such conversions occur when one input path has a frequency
response that is different from the other. To keep CMRR across
frequency high, the input source impedance and capacitance of
each path should be closely matched. Additional source resistance
in the input path (for example, for input protection) should be
placed close to the in-amp inputs, which minimizes their
interaction with parasitic capacitance from the PCB traces.
Parasitic capacitance at the gain-setting pins can also affect
CMRR over frequency. If the board design has a component
at the gain-setting pins (for example, a switch or jumper), the
part should be chosen so that the parasitic capacitance is as
small as possible.
Power Supplies
A stable dc voltage should be used to power the instrumentation
amplifier. Note that noise on the supply pins can adversely affect
performance. For more information, see the PSRR performance
curves in Figure 23 and Figure 24.
A 0.1 µF capacitor should be placed as close as possible to each
supply pin. As shown in Figure 61, a 10 µF tantalum capacitor
can be used farther away from the part. In most cases, it can be
shared by other precision integrated circuits.
References
The output voltage of the AD8226 is developed with respect to
the potential on the reference terminal. Care should be taken to
tie REF to the appropriate local ground.
Figure 61. Supply Decoupling, REF, and Output Referred to Local Ground
+IN
–IN
AD8226
+V
–V
S
S
0.1µF
0.1µF
REF
10µF
10µF
LOAD
V
OUT
Rev. B | Page 21 of 28
INPUT BIAS CURRENT RETURN PATH
The input bias current of the AD8226 must have a return path
to ground. When the source, such as a thermocouple, cannot
provide a return current path, one should be created, as shown
in Figure 62.
CAPACITIVELY COUPLED
C
C
THERMOCOUPLE
TRANSFORMER
INCORRECT
AD8226
+V
AD8226
–V
AD8226
+V
–V
+V
–V
S
S
S
S
S
S
REF
Figure 62. Creating an I
REF
REF
f
HIGH-PASS
=
CAPACITIVELY COUPLED
2πRC
1
10MΩ
BIAS
C
C
Path
R
R
THERMOCOUPLE
TRANSFORMER
CORRECT
AD8226
AD8226
AD8226
+V
–V
+V
–V
+V
–V
S
S
S
S
S
S
AD8226
REF
REF
REF