AD627ARZ Analog Devices Inc, AD627ARZ Datasheet - Page 16

• Manufacturer Part Number: AD627ARZ
• Description: IC AMP INST R-R 25MA 8SOIC
• Manufacturer: Analog Devices Inc
• Type: Rail-to-Railr

Specifications of AD627ARZ

• Slew Rate: 0.06 V/µs
• 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
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• No. Of Amplifiers: 1
• Input Offset Voltage: 200µV
• Gain Db Min: 5dB
• Gain Db Max: 1000dB
• Bandwidth: 40MHz
• Amplifier Output: Rail To Rail
• Cmrr: 77dB
• Supply Voltage Range: ± 1.1V To ±
• Common Mode Rejection Ratio: 90
• Current, Input Bias: 3 nA (Single), 2 nA (Dual)
• Current, Input Offset: 0.3 nA
• Current, Supply: 60 μA
• Impedance, Thermal: 155 °C/W
• Package Type: SOIC-8
• Power Dissipation: 0.8 W
• Resistance, Input: 20 Gigaohms (Differential), 20 Gigaohms (Common-Mode)
• Temperature, Operating, Range: -40 to +85 °C
• Voltage, Gain: 1000 V/V
• Voltage, Input: -35.9 to +35 V (Single), -17.9 to +17 V (Dual)
• Voltage, Input Offset: 50 μV (Single), 25 μV (Dual)
• Voltage, Noise: 38 nV/sqrt Hz
• Voltage, Supply: 2.2 to ±18 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Gain Bandwidth Product: -
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

AD627
A 4 mA-to-20 mA Single Supply Receiver
Figure 16 shows how a signal from a 4 mA-to-20 mA transducer
can be interfaced to the ADµC812, a 12-bit ADC with an embed-
ded microcontroller. The signal from a 4 mA-to-20 mA transducer
is single ended. This initially suggests the need for a simple shunt
resistor, to convert the current to a voltage at the high imped-
ance analog input of the converter. However, any line resistance
in the return path (to the transducer) will add a current depen-
dent offset error. So the current must be sensed differentially.
In this example, a 24.9 Ω shunt resistor generates a maximum
differential input voltage to the AD627 of between 100 mV (for
4 mA in) and 500 mV (for 20 mA in). With no gain resistor
present, the AD627 amplifies the 500 mV input voltage by a
factor of 5, to 2.5 V, the full-scale input voltage of the ADC.
The zero current of 4 mA corresponds to a code of 819 and the
LSB size is 4.9 mA.
A Thermocouple Amplifier
Because the common-mode input range of the AD627 extends
0.1 V below ground, it is possible to measure small differential
signals which have low, or no, common-mode component. Fig-
ure 17 shows a thermocouple application where one side of the
J-type thermocouple is grounded.
AD627–Revision History
Location
Data Sheet changed from REV. A to REV. B.
Changes to Figure 4 and Table I, Resulting Gain column . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Change to Figure 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
0.210 (5.33)
0.160 (4.06)
0.115 (2.93)
PIN 1
0.022 (0.558)
0.014 (0.356)
MAX
8
0.430 (10.92)
1
0.348 (8.84)
0.100
(2.54)
BSC
MicroConverter is a trademark of Analog Devices, Inc.
8-Lead Plastic DIP
0.070 (1.77)
0.045 (1.15)
TRANSDUCER
5
4
4–20mA
0.060 (1.52)
0.015 (0.38)
0.280 (7.11)
0.240 (6.10)
(N-8)
0.130
(3.30)
MIN
SEATING
PLANE
IMPEDANCE
0.325 (8.25)
0.300 (7.62)
LINE
0.015 (0.381)
0.008 (0.204)
4–20mA
Dimensions shown in inches and (mm).
0.195 (4.95)
0.115 (2.93)
OUTLINE DIMENSIONS
24.9
G = +5
Over a temperature range from –200°C to +200°C, the J-type
thermocouple delivers a voltage ranging from –7.890 mV to
10.777 mV. A programmed gain on the AD627 of 100 (R
2.1 kΩ) and a voltage on the AD627 REF pin of 2 V, results in
the AD627’s output voltage ranging from 1.110 V to 3.077 V
relative to ground. For a different input range or different volt-
age on the REF pin, it is important to check that the voltage on
internal node A1 (see Figure 4) is not driven below ground).
This can be checked using the equations in the section entitled
Input Range Limitations in Single Supply Applications.
0.0098 (0.25)
0.0040 (0.10)
THERMOCOUPLE
AD627
0.1574 (4.00)
0.1497 (3.80)
5V
0.1 F
PIN 1
SEATING
REF
PLANE
J-TYPE
0.1968 (5.00)
0.1890 (4.80)
0.0500 (1.27)
8
1
BSC
AIN 0–7
0.0192 (0.49)
0.0138 (0.35)
V
REF
5
4
AVDD
AGND
8-Lead SOIC
0.2440 (6.20)
0.2284 (5.80)
5V
0.0688 (1.75)
0.0532 (1.35)
0.1 F
MicroConverter
(SO-8)
AD C812
DGND
DVDD
0.0098 (0.25)
0.0075 (0.19)
5V
2.1k
0.1 F
R
G
TM
AD627
8
0
+5V
0.0196 (0.50)
0.0099 (0.25)
0.0500 (1.27)
0.0160 (0.41)
0.1 F
REF
V
2V
45
G
OUT
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