AD8276BRZ-RL Analog Devices Inc, AD8276BRZ-RL Datasheet - Page 14

• Manufacturer Part Number: AD8276BRZ-RL
• Description: Single G=1 LowPower,WideInputRange
• Manufacturer: Analog Devices Inc

Specifications of AD8276BRZ-RL

• Design Resources: High Precision, Low Cost Current Sources Using AD8276 and AD8603 (CN0099)
• Amplifier Type: Differential
• Number Of Circuits: 1
• Output Type: Rail-to-Rail
• Slew Rate: 1.1 V/µs
• Gain Bandwidth Product: 550kHz
• Voltage - Input Offset: 100µV
• Current - Supply: 200µA
• Current - Output / Channel: 15mA
• Voltage - Supply, Single/dual (±): 2 V ~ 36 V, ±2 V ~ 18 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• -3db Bandwidth: -
• Current - Input Bias: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD8276
INSTRUMENTATION AMPLIFIER
The AD8276 can be used as a building block for a low power,
low cost instrumentation amplifier. An instrumentation amplifier
provides high impedance inputs and delivers high common-
mode rejection. Combining the AD8276 with an Analog Devices
low power amplifier (examples provided in Table 7) creates a
precise, power efficient voltage measurement solution suitable
for power critical systems.
Table 7. Low Power Op Amps
Op Amp (A1, A2)
AD8506
AD8607
AD8617
AD8667
–IN
+IN
R
Figure 44. Low Power Precision Instrumentation Amplifier
G
A1
A2
R
R
F
F
Features
Dual micropower op amp
Precision dual micropower op amp
Low cost CMOS micropower op amp
Dual precision CMOS micropower op amp
40kΩ
40kΩ
40kΩ
V
OUT
REF
= (1 + 2R
V+
V–
AD8276
1
2
3
4
5
40kΩ
F
REF
/R
ADR821
G
) (V
IN+
– V
V
IN–
OUT
Figure 45. Constant Current Source
)
10
9
8
7
6
Rev. 0 | Page 14 of 16
–2.5V
2
3
40kΩ
40kΩ
AD8276
7
4
V+
It is preferable to use dual op amps for the high impedance inputs,
because they have better matched performance and track each
other over temperature. The AD8276 difference amplifier can-
cels out common-mode errors from the input op amps, if they
track each other. The differential gain accuracy of the in-amp
is proportional to how well the input feedback resistors (R
match each other. The CMRR of the in-amp increases as the
differential gain is increased (1 + 2R
reduces the common-mode voltage range. Refer to
Guide to Instrumentation Amplifiers
considerations.
CURRENT SOURCE
The AD8276 difference amplifier can be implemented as part
of a voltage-to-current converter or a precision constant current
source as shown in Figure 45. The internal resistors are tightly
matched to minimize error and temperature drift. If the exter-
nal resistors R1 and R2 are not well-matched, they will be a
significant source of error in the system, so precision resistors
are recommended to maintain performance. The
provides a precision voltage reference and integrated op amp
that also reduces error in the signal chain.
The AD8276 has rail-to-rail output capability, which allows
higher current outputs.
40kΩ
40kΩ
I
R1 = R2
O
= 2.5V(1/40kΩ + 1/R1)
5
6
1
2N3904
R2
R1
R
LOAD
F
for more design ideas and
/R
G
), but a higher gain also
ADR821
A Designer’s
F
)