AD629A AD [Analog Devices], AD629A Datasheet - Page 3

• Manufacturer Part Number: AD629A
• Description: High Common-Mode Voltage Difference Amplifier
• Manufacturer: AD [Analog Devices]

ABSOLUTE MAXIMUM RATINGS
Supply Voltage V
Internal Power Dissipation
Input Voltage Range, Continuous . . . . . . . . . . . . . . . . ± 300 V
Common-Mode and Differential, 10 sec . . . . . . . . . . . ± 500 V
Output Short Circuit Duration . . . . . . . . . . . . . . . . Indefinite
Pin 1, Pin 5 . . . . . . . . . . . . . . . . . . –V
Maximum Junction Temperature . . . . . . . . . . . . . . . . . 150°C
Operating Temperature Range . . . . . . . . . . –55°C to +125°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature Range (Soldering 60 sec) . . . . . . . . . 300°C
NOTES
1
2
REV. A
Model
AD629AR
AD629AR-REEL
AD629AR-REEL7
AD629BR
AD629BR-REEL
AD629BR-REEL7
AD629AN
AD629BN
NOTES
1
2
Stresses above those listed under Absolute Maximum Ratings may cause perma-
Specification is for device in free air: 8-Lead Plastic DIP, θ
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD629 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may effect device reliability.
SOIC Package, θ
Figure 3. Derating Curve of Maximum Power Dissipation
vs. Temperature for SOIC and PDIP Packages
13" Tape and Reel of 2500 each
7" Tape and Reel of 1000 each
DIP (N) . . . . . . . . . . . . . . . . . . . . . . . . See Derating Curves
SOIC (R) . . . . . . . . . . . . . . . . . . . . . . . See Derating Curves
2.0
1.5
1.0
0.5
0
–50
–40 –30 –20 –10 0
JA
= 155°C/W.
S
1
1
8-LEAD SOIC PACKAGE
2
2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 18 V
AMBIENT TEMPERATURE – C
8-LEAD MINI-DIP PACKAGE
2
10 20 30 40 50 60 70 80 90
1
S
Temperature
Range
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
– 0.3 V to +V
JA
T
= 100°C/W; 8-Lead
J
= 150 C
S
ORDERING GUIDE
+ 0.3 V
–3–
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.
In order to achieve high common-mode voltage range, an internal
resistor divider (Pin 3, Pin 5) attenuates the noninverting signal
by a factor of 20. Other internal resistors (Pin 1, Pin 2, and the
feedback resistor) restores 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.
The op amp itself, in order to reduce output drift, 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. This has the added benefit of
reducing voltage noise because the corner where 1/f noise becomes
dominant is below 5 Hz. In order 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.
Package
Description
8-Lead Plastic SOIC
8-Lead Plastic SOIC
8-Lead Plastic SOIC
8-Lead Plastic SOIC
8-Lead Plastic SOIC
8-Lead Plastic SOIC
8-Lead Plastic DIP
8-Lead Plastic DIP
Figure 4. Functional Block Diagram
REF(–)
–V
+IN
–IN
V
S
OUT
1
2
3
4
21.1k
380k
380k
= V (+IN ) – V (–IN )
NC = NO CONNECT
AD629
380k
20k
WARNING!
8
7
6
5
NC
+V
OUTPUT
REF(+)
S
ESD SENSITIVE DEVICE
AD629
Package
Option
SO-8
SO-8
SO-8
SO-8
SO-8
SO-8
N-8
N-8