AD627AR Analog Devices Inc, AD627AR Datasheet - Page 20

• Manufacturer Part Number: AD627AR
• Description: IC AMP INST R-R 25MA 8SOIC
• Manufacturer: Analog Devices Inc

Specifications of AD627AR

• 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
• Amplifier Case Style: SOIC
• No. Of Pins: 8
• Programmable Gain Max: 1000
• Supply Voltage Min: 2.2V
• Gain Min, V/v: 5
• Gain Max, V/v: 1000
• Gain Bandwidth Product: -
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

AD627
LAYOUT AND GROUNDING
The use of ground planes is recommended to minimize the
impedance of ground returns (and hence, the size of dc errors).
To isolate low level analog signals from a noisy digital environment,
many data acquisition components have separate analog and
digital ground returns (see Figure 47). Return all ground pins
from mixed-signal components, such as analog-to-digital
converters, through the high quality analog ground plane.
Digital ground lines of mixed-signal components should also
be returned through the analog ground plane. This may seem
to break the rule of separating analog and digital grounds;
however, in general, there is also a requirement to keep the
voltage difference between digital and analog grounds on a
converter as small as possible (typically, <0.3 V). The increased
noise, caused by the digital return currents of the converter
flowing through the analog ground plane, is generally negligible.
To maximize isolation between analog and digital, connect the
ground planes back at the supplies.
Figure 47. Optimal Grounding Practice for a Bipolar Supply Environment with Separate Analog and Digital Supplies
2
3
AD627
AD627
2
3
7
Figure 48. Optimal Ground Practice in a Single-Supply Environment
0.1µF
AD627
7
0.1µF
4
5
ANALOG POWER SUPPLY
+5V
4
5
6
6
–5V
4
3
Rev. D | Page 20 of 24
GND
V
V
4
IN1
IN2
V
IN
1
POWER SUPPLY
V
ADC
5V
V
DD
1
DD
ADC
6
If there is only one power supply available, it must be shared by
both digital and analog circuitry. Figure 48 shows how to minimize
interference between the digital and analog circuitry. As in the
previous case, use separate analog and digital ground planes or
use reasonably thick traces as an alternative to a digital ground
plane. Connect the ground planes at the ground pin of the power
supply. Run separate traces (or power planes) from the power
supply to the supply pins of the digital and analog circuits. Ideally,
each device should have its own power supply trace, but they
can be shared by multiple devices if a single trace is not used to
route current to both digital and analog circuitry.
AGND
AD7892-2
GND
AGND
AD7892-2
14
DGND
DGND
DIGITAL POWER SUPPLY
12
12
GND
AGND
PROCESSOR
MICRO-
PROCESSOR
V
DD
MICRO-
+5V
V
DD
DGND