Low Power, Rail-to-Rail Output, Precision
JFET Amplifiers
Data Sheet
AD8641/AD8642/AD8643
Rev. F Document Feedback
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FEATURES
Low supply current: 250 μA max
Very low input bias current: 1 pA max
Low offset voltage: 750 μV max
Single-supply operation: 5 V to 26 V
Dual-supply operation: ±2.5 V to ±13 V
Rail-to-rail output
Unity-gain stable
No phase reversal
SC70 package
APPLICATIONS
Line-/battery-powered instruments
Photodiode amplifiers
Precision current sensing
Medical instrumentation
Industrial controls
Precision filters
Portable audio
ATE
GENERAL DESCRIPTION
The AD8641/AD8642/AD8643 are low power, precision JFET
input amplifiers featuring extremely low input bias current and
rail-to-rail output. The ability to swing nearly rail-to-rail at the
input and rail-to-rail at the output enables designers to buffer
complementary metal-oxide semiconductor digital-to-analog
converters (CMOS DACs), ASICs, and other wide output swing
devices in single-supply systems. The outputs remain stable
with capacitive loads of more than 500 pF.
The AD8641/AD8642/AD8643 are suitable for applications
utilizing multichannel boards that require low power to manage
heat. Other applications include photodiodes, ATE reference
level drivers, battery management, and industrial controls.
The AD8641/AD8642/AD8643 are fully specified over the
extended industrial temperature range of −40°C to +125°C. The
AD8641 is available in 5-lead SC70 and 8-lead SOIC lead-free
packages. The AD8642 is available in 8-lead MSOP and 8-lead
SOIC lead-free packages. The AD8643 is available in 14-lead
SOIC and 16-lead, 3 mm × 3 mm, LFCSP lead-free packages.
PIN CONFIGURATIONS
OUT
1
+IN
3
VEE
2
VCC
5
–IN
4
AD8641
TOP VIEW
(Not to Scale)
05072-101
Figure 1. 5-Lead SC70 (KS-5)
NIC
–IN
+IN
VEE
NIC
VCC
OUT
NIC
05072-102
NIC = NO INTERN
L CONNECTION.
1
2
3
4
8
7
6
5
AD8641
TOP VIEW
(Not to Scale)
Figure 2. 8-Lead SOIC (R-8)
OUT A
1
–IN A
2
+IN A
3
V–
4
V+
8
OUT B
7
–IN B
6
+IN B
5
AD8642
TOP VIEW
(Not to Scale)
05072-105
Figure 3. 8-Lead SOIC (R-8)
OUT A
1
–IN A
2
+IN A
3
V–
4
V+
8
OUT B
7
–IN B
6
+IN B
5
AD8642
TOP VIEW
(Not to Scale)
05072-064
Figure 4. 8-Lead MSOP (RM-8)
05072-103
OUT
1
OUT D
14
–IN A
2
–IN D
13
+IN A
3
+IN D
12
V+
4
V–
11
+IN B
5
+IN C
10
–IN B
6
–IN C
9
OUT B
7
OUT C
8
TOP VIEW
(Not to Scale)
AD8643
Figure 5. 14-Lead SOIC (R-14)
05072-104
+IN C
V–
+IN D
–IN D
–IN B
OUT B
OUT C
–IN C
–IN A
+IN B
V+
+IN A
PIN 1
INDICATOR
NIC
OUT A
OUT D
NIC
NOTES
1. NIC = NO INTERNAL CONNECTION.
2. EXPOSED PAD SHOULD BE CONNECTED TO V+.
12
11
10
1
3
4
9
2
6
5
7
8
16
15
14
13
AD8643
TOP VIEW
Figure 6. 16-Lead LFCSP (CP-16-27) (Not Drawn to Scale)
