AD8227BRMZ-RL Analog Devices Inc, AD8227BRMZ-RL Datasheet - Page 21

• Manufacturer Part Number: AD8227BRMZ-RL
• Description: LowCostWideInputRangeInAmp G-5
• Manufacturer: Analog Devices Inc

Specifications of AD8227BRMZ-RL

• Amplifier Type: Instrumentation
• Number Of Circuits: 1
• Output Type: Rail-to-Rail
• Slew Rate: 0.8 V/µs
• -3db Bandwidth: 250kHz
• Current - Input Bias: 20nA
• Voltage - Input Offset: 100µV
• Current - Supply: 350µA
• Current - Output / Channel: 13mA
• Voltage - Supply, Single/dual (±): 2.2 V ~ 36 V, ±1.5 V ~ 18 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Gain Bandwidth Product: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

INPUT BIAS CURRENT RETURN PATH
The input bias current of the AD8227 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.
INPUT PROTECTION
The AD8227 has very robust inputs and typically does not need
additional input protection. Input voltages can be up to 40 V
from the opposite supply rail. For example, with a +5 V positive
supply and a −8 V negative supply, the part can safely withstand
voltages from −35 V to +32 V. Unlike some other instrumentation
amplifiers, the part can handle large differential input voltages
even when the part is in high gain. Figure 17 through Figure 20
show the behavior of the part under overvoltage conditions.
CAPACITIVELY COUPLED
C
C
THERMOCOUPLE
TRANSFORMER
INCORRECT
Figure 62. Creating an Input Bias Current Return Path
AD8227
AD8227
+V
–V
AD8227
+V
–V
+V
–V
S
S
S
S
S
S
REF
REF
REF
f
HIGH-PASS
=
CAPACITIVELY COUPLED
2πRC
1
10MΩ
C
C
R
R
THERMOCOUPLE
TRANSFORMER
CORRECT
AD8227
AD8227
AD8227
+V
–V
+V
–V
+V
–V
S
S
S
S
S
S
REF
REF
REF
Rev. 0 | Page 21 of 24
The other AD8227 terminals should be kept within the supplies.
All terminals of the AD8227 are protected against ESD.
For applications where the AD8227 encounters voltages beyond
the allowed limits, external current limiting resistors and low
leakage diode clamps such as the BAV199L, the FJH1100s, or
the SP720 should be used.
RADIO FREQUENCY INTERFERENCE (RFI)
RF rectification is often a problem when amplifiers are used in
applications that have strong RF signals. The disturbance can
appear as a small dc offset voltage. High frequency signals can
be filtered with a low-pass RC network placed at the input of
the instrumentation amplifier, as shown in Figure 63. The filter
limits the input signal bandwidth, according to the following
relationship:
where C
C
mode signal. Values of R and C
RFI. A mismatch between R × C
R × C
By using a value of C
of the mismatch is reduced, and performance is improved.
D
affects the differential signal and C
FilterFreq
FilterFreq
C
at the negative input degrades the CMRR of the AD8227.
D
≥ 10 C
4.02kΩ
4.02kΩ
R
R
uency
uency
C
.
C
1nF
C
10nF
C
1nF
DIFF
CM
D
C
D
C
Figure 63. RFI Suppression
one magnitude larger than C
=
=
π 2
R
π 2
0.1µF
0.1µF
G
RC
1
+IN
–IN
R
C
2 (
C
C
should be chosen to minimize
C
at the positive input and
AD8227
1
+V
–V
D
S
S
+
C
C
affects the common-
C
)
REF
10µF
10µF
V
OUT
C
AD8227
, the effect