AD629BNZ Analog Devices Inc, AD629BNZ Datasheet - Page 10

• Manufacturer Part Number: AD629BNZ
• Description: IC AMP DIFF 25MA LDRIFT 8DIP
• Manufacturer: Analog Devices Inc

Specifications of AD629BNZ

• Design Resources: Measuring -48 V High-Side Current Using AD629, AD8603, AD780, and AD7453 (CN0100)
• Amplifier Type: Differential
• Number Of Circuits: 1
• Slew Rate: 2.1 V/µs
• -3db Bandwidth: 500kHz
• Voltage - Input Offset: 100µV
• Current - Supply: 900µA
• Current - Output / Channel: 25mA
• Voltage - Supply, Single/dual (±): 5 V ~ 36 V, ±2.5 V ~ 18 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• No. Of Amplifiers: 1
• Input Offset Voltage: 500µV
• Gain Db Max: 1dB
• Bandwidth: 500kHz
• Supply Voltage Range: ± 2.5V To ± 18V
• Supply Current: 900µA
• Amplifier Case Style: DIP
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Output Type: -
• Gain Bandwidth Product: -
• Current - Input Bias: -

AD629
THEORY OF OPERATION
The AD629 is a unity gain, differential-to-single-ended
amplifier (diff amp) that can reject extremely high common-
mode signals (in excess of 270 V with 15 V supplies). It consists
of an operational amplifier (op amp) and a resistor network.
To achieve high common-mode voltage range, an internal
resistor divider (Pin 3 or Pin 5) attenuates the noninverting
signal by a factor of 20. Other internal resistors (Pin 1, Pin 2,
and the feedback resistor) restore the gain to provide a differential
gain of unity. The complete transfer function equals
Laser wafer trimming provides resistor matching so that
common-mode signals are rejected while differential input
signals are amplified.
V
OUT
= V (+IN) − V (−IN)
Rev. C | Page 10 of 16
To reduce output drift, the op amp uses super beta transistors
in its input stage. The input offset current and its associated
temperature coefficient contribute no appreciable output
voltage offset or drift, which has the added benefit of reducing
voltage noise because the corner where 1/f noise becomes
dominant is below 5 Hz. To reduce the dependence of gain
accuracy on the op amp, the open-loop voltage gain of the op
amp exceeds 20 million, and the PSRR exceeds 140 dB.
REF(–)
–V
+IN
–IN
Figure 31. Functional Block Diagram
S
1
2
3
4
21.1kΩ
380kΩ
380kΩ
AD629
NC = NO CONNECT
380kΩ
20kΩ
8
7
6
5
NC
+V
OUTPUT
REF(+)
S