AD8275BRMZ Analog Devices Inc, AD8275BRMZ Datasheet - Page 15

• Manufacturer Part Number: AD8275BRMZ
• Description: IC AMP DIFF R-R LDRIFT 8MSOP
• Manufacturer: Analog Devices Inc

Specifications of AD8275BRMZ

• Amplifier Type: Differential
• Number Of Circuits: 1
• Output Type: Rail-to-Rail
• Slew Rate: 25 V/µs
• -3db Bandwidth: 15MHz
• Voltage - Input Offset: 150µV
• Current - Supply: 1.9mA
• Current - Output / Channel: 30mA
• Voltage - Supply, Single/dual (±): 3.3 V ~ 15 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• No. Of Amplifiers: 1
• Input Offset Voltage: 500µV
• Bandwidth: 15MHz
• Supply Voltage Range: 3.3V To 15V
• Supply Current: 1.9mA
• Amplifier Case Style: MSOP
• No. Of Pins: 8
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Gain Bandwidth Product: -
• Current - Input Bias: -

INCREASING INPUT IMPEDANCE
In applications where a high input impedance is needed, low
input bias current op amps can be used to buffer the AD8275.
In Figure 41, an
ance. Input bias current is limited to 10 pA.
INVERTING
AC COUPLING
An integrator can be tied to the AD8275 in feedback to create a
high-pass filter as shown in Figure 42. This circuit can be used
to reject dc voltages and offsets. At low frequencies, the impedance
of the capacitor, C, is high. Thus, the gain of the integrator is
high. DC voltage at the output of the AD8275 is inverted and
gained by the integrator. The inverted signal is injected back
into the REFx pins, nulling the output. In contrast, at high fre-
quencies, the integrator has low gain because the impedance of
C is low. Voltage changes at high frequencies are inverted but at
a low gain. The signal is injected into the REFx pins but it is not
enough to null the output. High frequency signals are, therefore,
allowed to pass.
When a signal exceeds f
conditioned input signal.
INVERTING
INPUT
INPUT
NON-
Figure 41. Adding Op Amp Buffers for High Input Impedance
2
5
3
6
2
3
AD8275
+IN
–IN
AD8620
AD8620
50kΩ
50kΩ
+13V
–13V
4
8
+5V
1/2
Figure 42. AC-Coupled Level Translator
2/2
AD8620
+V
–V
4
7
0.1µF
0.1µF
S
S
10kΩ
20kΩ
20kΩ
1
7
HIGH-PASS
SENSE
is used to provide high input imped-
REF2
REF1
OUT
0.1µF
2
3
AD8275
–IN
+IN
5
6
8
1
, the AD8275 outputs the
50kΩ
50kΩ
0.1µF
+5V
+V
–V
10kΩ
7
4
20kΩ
20kΩ
S
S
f
+5V
HIGH-PASS
C
AMP
SENSE
OP
REF2
REF1
OUT
0.1µF
5
6
8
1
=
R
2πRC
V
REF
1
V
V
REF
OUT
V
Rev. A | Page 15 of 16
OUT
USING THE AD8275 AS A LEVEL TRANSLATOR IN
A DATA ACQUISITION SYSTEM
Signal size varies dramatically in some data acquisition applica-
tions. Instrumentation amplifiers, such as the AD8253, AD8228,
or AD8221, are often used at the inputs to provide CMRR and
high input impedance. However, the instrumentation amplifiers
output ±10 V signals and the ADC full scale is 5 V or 4.096 V.
In Figure 43, the AD8275 serves as a level translator between
the in-amp and the ADC. The AD8275, along with the AD8228
and the AD8253, have very low gain drift because all gain setting
resistors are internal and laser-trimmed.
+15V
–15V
IN-AMP
Figure 43. Level Translation in a Data Acquisition System
0.1µF
0.1µF
2
3
–IN
+IN
AD8275
50kΩ
50kΩ
+5V
+V
–V
4
7
S
S
10kΩ
20kΩ
20kΩ
SENSE
REF2
REF1
OUT
0.1µF
5
6
8
1
2.7nF
33Ω
VREF
0.1µF
10µF
+IN
–IN
AD8275
REF
ADC
VCC
GND