AD627BR Analog Devices Inc, AD627BR Datasheet - Page 15

• Manufacturer Part Number: AD627BR
• Description: IC AMP INST R-R 25MA 8SOIC
• Manufacturer: Analog Devices Inc

Specifications of AD627BR

• Slew Rate: 0.06 V/µs
• Mounting Type: Surface Mount
• Rohs Status: RoHS non-compliant
• Amplifier Type: Instrumentation
• Number Of Circuits: 1
• Output Type: Rail-to-Rail
• -3db Bandwidth: 80kHz
• Current - Input Bias: 2nA
• Voltage - Input Offset: 25µV
• Current - Supply: 60µA
• Current - Output / Channel: 25mA
• Voltage - Supply, Single/dual (±): 2.2 V ~ 36 V, ±1.1 V ~ 18 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-SOIC (3.9mm Width)
• No. Of Amplifiers: 1
• Bandwidth: 80kHz
• Amplifier Case Style: SOIC
• No. Of Pins: 8
• Single Supply Voltage Min (+v): 1.1V
• Programmable Gain Max: 1000
• Gain Bandwidth Product: -
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

USING THE AD627
BASIC CONNECTIONS
Figure 36 shows the basic connection circuit for the AD627.
The +V
supply can be either bipolar (V
supply (−V
the power supplies close to the power pins of the device. For
best results, use surface-mount 0.1 μF ceramic chip capacitors.
The input voltage can be single-ended (tie either −IN or +IN to
ground) or differential. The difference between the voltage on the
inverting and noninverting pins is amplified by the programmed
gain. The gain resistor programs the gain as described in
the Setting the Gain and Reference Terminal sections. Basic
connections are shown in Figure 36. The output signal appears
as the voltage difference between the output pin and the
externally applied voltage on the REF pin, as shown in Figure 37.
S
and −V
S
= 0 V, +V
S
terminals connect to the power supply. The
S
= 2.2 V to 36 V). Capacitively decouple
V
S
V
DIFF
2
IN
= ±1.1 V to ±18 V) or single
+IN
–IN
R
G
V+
V–
Figure 37. Amplifying Differential Signals with a Common-Mode Component
R
R
+IN
–IN
G
G
+V
–V
OUTPUT
REF
S
S
0.1µF
0.1µF
Figure 36. Basic Connections for Single and Dual Supplies
+1.1V TO +18V
–1.1V TO –18V
REF
–IN
2kΩ
100kΩ
V
REF (INPUT)
OUT
+V
–V
Rev. D | Page 15 of 24
S
S
GAIN = 5 + (200kΩ/R
EXTERNAL GAIN RESISTOR
Q1
200kΩ
V
IN
25kΩ
+IN
–IN
R
A1
SETTING THE GAIN
The gain of the AD627 is resistor programmed by R
precisely, by whatever impedance appears between Pin 1 and Pin 8.
The gain is set according to
Therefore, the minimum achievable gain is 5 (for 200 kΩ/
(Gain − 5)). With an internal gain accuracy of between 0.05%
and 0.7%, depending on gain and grade, a 0.1% external gain
resistor is appropriate to prevent significant degradation of the
overall gain error. However, 0.1% resistors are not available in a
wide range of values and are quite expensive. Table 6 shows
recommended gain resistor values using 1% resistors. For all
gains, the size of the gain resistor is conservatively chosen as the
closest value from the standard resistor table that is higher than
the ideal value. This results in a gain that is always slightly less
than the desired gain, thereby preventing clipping of the signal
at the output due to resistor tolerance.
The internal resistors on the AD627 have a negative temperature
coefficient of −75 ppm/°C maximum for gains > 5. Using a
gain resistor that also has a negative temperature coefficient
of −75 ppm/°C or less tends to reduce the overall gain drift of
the circuit.
G
0.1V
G
R
R
R
Gain = 5 + (200 kΩ/R
)
G
G
G
+V
25kΩ
OUTPUT
REF
S
V
0.1µF
A
+2.2V TO +36V
Q2
200kΩ
–V
+V
S
S
A2
100kΩ
2kΩ
V
REF (INPUT)
OUT
+IN
G
) or R
OUTPUT
–V
G
= 200 kΩ/(Gain − 5)
S
G
, or, more
AD627
(2)