AD648JRZ Analog Devices Inc, AD648JRZ Datasheet - Page 10

• Manufacturer Part Number: AD648JRZ
• Description: IC OPAMP BIFET 1MHZ DUAL 8SOIC
• Manufacturer: Analog Devices Inc

Specifications of AD648JRZ

• Slew Rate: 1.8 V/µs
• Amplifier Type: J-FET
• Number Of Circuits: 2
• Gain Bandwidth Product: 1MHz
• Current - Input Bias: 5pA
• Voltage - Input Offset: 750µV
• Current - Supply: 340µA
• Current - Output / Channel: 15mA
• Voltage - Supply, Single/dual (±): ±4.5 V ~ 18 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Op Amp Type: Precision
• No. Of Amplifiers: 2
• Bandwidth: 1MHz
• Supply Voltage Range: ± 4.5V To ± 18V
• Amplifier Case Style: SOIC
• No. Of Pins: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Output Type: -
• -3db Bandwidth: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

AD648
INSTRUMENTATION AMPLIFIER
The AD648J’s maximum input current of 20 pA per amplifier
makes it an excellent building block for the high input impedance
instrumentation amplifier shown in Figure 29. Total current
drain for this circuit is under 600 µA. This configuration is
optimal for conditioning differential voltages from high imped-
ance sources.
The overall gain of the circuit is controlled by R
the following transfer function:
Gains of 1 to 100 can be accommodated with gain nonlinearities
of less than 0.01%. The maximum input current is 30 pA over
V
V
OUT
IN
= 1 +
(R3 + R4)
R
G
Figure 29. Low Power Instrumentation Amplifier
G
, resulting in
–10–
the common-mode range, with a common-mode impedance of
over 1 × 10
for peaking in the gain over frequency which is caused by input
capacitance.
To calibrate this circuit, first adjust trimmer R1 for common-
mode rejection with 10 V dc applied to the input pins. Next,
adjust R2 for zero offset at V
Trim the circuit a second time for optimal
performance.
The –3 dB small signal bandwidth for this low power instru-
mentation amplifier is 700 kHz for a gain of 1 and 10 kHz for a
gain of 100. The typical output slew rate is 1.8 V/µs.
12
Ω. The capacitors C1, C2, C3 and C4 compensate
OUT
with both inputs grounded.
REV. E