Precision Micropower, Low Noise CMOS,
Rail-to-Rail Input/Output Operational Amplifiers
AD8603/AD8607/AD8609
Rev. C
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FEATURES
Low offset voltage: 50 μV maximum
Low input bias current: 1 pA maximum
Single-supply operation: 1.8 V to 5 V
Low noise: 22 nV/√Hz
Micropower: 50 μA maximum
Low distortion
No phase reversal
Unity gain stable
APPLICATIONS
Battery-powered instrumentation
Multipole filters
Sensors
Low power ASIC input or output amplifiers
GENERAL DESCRIPTION
The AD8603/AD8607/AD8609 are single/dual/quad micro-
power rail-to-rail input and output amplifiers, respectively, that
feature very low offset voltage as well as low input voltage and
current noise.
These amplifiers use a patented trimming technique that achieves
superior precision without laser trimming. The parts are fully
specified to operate from 1.8 V to 5.0 V single supply or from
±0.9 V to ±2.5 V dual supply. The combination of low offsets, low
noise, very low input bias currents, and low power consumption
makes the AD8603/AD8607/AD8609 especially useful in portable
and loop-powered instrumentation.
The ability to swing rail to rail at both the input and output
enables designers to buffer CMOS ADCs, DACs, ASICs, and
other wide output swing devices in low power, single-supply
systems.
The AD8603 is available in a tiny 5-lead TSOT package. The
AD8607 is available in 8-lead MSOP and 8-lead SOIC packages.
The AD8609 is available in 14-lead TSSOP and 14-lead SOIC
packages.
PIN CONFIGURATIONS
04356-001
OUT 1
V– 2
+IN 3
V+5
–IN4
AD8603
TOP VIEW
(Not to Scale)
Figure 1. 5-Lead TSOT (UJ Suffix)
04356-002
OUT A
1
–IN A
2
+IN A
3
V–
4
V+
8
OUT B
7
–IN B
6
+IN B
5
AD8607
TOP VIEW
(Not to Scale)
Figure 2. 8-Lead MSOP (RM Suffix)
04356-003
OUT A
1
–IN A
2
+IN A
3
V–
4
V+
8
OUT B
7
–IN B
6
+IN B
5
AD8607
TOP VIEW
(Not to Scale)
Figure 3. 8-Lead SOIC (R Suffix)
04356-004
1
2
3
4
5
6
7
AD8609
–IN A
+IN A
V+
OUT B
–IN B
+IN B
OUT A
14
13
12
11
10
9
8
–IN D
+IN D
V–
OUT C
–IN C
+IN C
OUT D
TOP VIEW
(Not to Scale)
Figure 4. 14-Lead TSSOP (RU Suffix)
OUT A
1
–IN A
2
+IN A
3
V+
4
OUT D
14
–IN D
13
+IN D
12
V–
11
+IN B
5
+IN C
10
–IN B
6
–IN C
9
OUT B
7
OUT C
8
AD8609
TOP VIEW
(Not to Scale)
0
4356-005
Figure 5. 14-Lead SOIC (R Suffix)
AD8603/AD8607/AD8609
Rev. C | Page 2 of 16
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Pin Configurations ........................................................................... 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Electrical Characteristics ............................................................. 3
Absolute Maximum Ratings ............................................................ 5
ESD Caution .................................................................................. 5
Typical Performance Characteristics ............................................. 6
Applications ..................................................................................... 12
No Phase Reversal ...................................................................... 12
Input Overvoltage Protection ................................................... 12
Driving Capacitive Loads .......................................................... 12
Proximity Sensors ....................................................................... 13
Composite Amplifiers ................................................................ 13
Battery-Powered Applications .................................................. 13
Photodiodes ................................................................................ 13
Outline Dimensions ....................................................................... 14
Ordering Guide .......................................................................... 16
REVISION HISTORY
6/08—Rev. B to Rev. C
Changes to Table 1 ............................................................................ 3
Changes to Table 2 ............................................................................ 4
Changes to Figure 15 ........................................................................ 7
Changes to Figure 33 ...................................................................... 10
Changes to Figure 45 and Figure 47 ............................................. 13
Updated Outline Dimensions ....................................................... 14
Changes to Ordering Guide .......................................................... 16
6/05—Rev. A to Rev. B
Updated Figure 49 .......................................................................... 15
Changes to Ordering Guide .......................................................... 17
10/03—Rev. 0 to Rev. A
Added AD8607 and AD8609 Parts .................................. Universal
Changes to Specifications ................................................................ 3
Changes to Figure 35 ...................................................................... 10
Added Figure 41 .............................................................................. 11
8/03—Revision 0: Initial Version
AD8603/AD8607/AD8609
Rev. C | Page 3 of 16
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
VS = 5 V, VCM = VS/2, TA = 25°C, unless otherwise noted.
Table 1.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage VOS V
S = 3.3 V @ VCM = 0.5 V and 2.8 V 12 50 μV
−0.3 V < VCM < +5.2 V 40 300 μV
−40°C < TA < +125°C, −0.3 V < VCM < +5.2 V 700 μV
Offset Voltage Drift ∆VOS/∆T −40°C < TA < +125°C 1 4.5 μV/°C
Input Bias Current IB 0.2 1 pA
−40°C < TA < +85°C 50 pA
−40°C < TA < +125°C 500 pA
Input Offset Current IOS 0.1 0.5 pA
−40°C < TA < +85°C 50 pA
−40°C < TA < +125°C 250 pA
Input Voltage Range IVR −0.3 +5.2 V
Common-Mode Rejection Ratio CMRR 0 V < VCM < 5 V 85 100 dB
−40°C < TA < +125°C 80 dB
Large Signal Voltage Gain AVO R
L = 10 kΩ, 0.5 V < VO < 4.5 V
AD8603 400 1000 V/mV
AD8607/AD8609 250 450 V/mV
Input Capacitance CDIFF 1.9 pF
C
CM 2.5 pF
OUTPUT CHARACTERISTICS
Output Voltage High VOH I
L = 1 mA 4.95 4.97 V
−40°C to +125°C 4.9 V
I
L = 10 mA 4.65 4.97 V
−40°C to +125°C 4.50 V
Output Voltage Low VOL I
L = 1 mA 16 30 mV
−40°C to +125°C 50 mV
I
L = 10 mA 160 250 mV
−40°C to +125°C 330 mV
Short-Circuit Current ISC ±70 mA
Closed-Loop Output Impedance ZOUT f = 10 kHz, AV = 1 36 Ω
POWER SUPPLY
Power Supply Rejection Ratio PSRR 1.8 V < VS < 5 V 80 100 dB
Supply Current per Amplifier ISY V
O = 0 V 40 50 μA
−40°C <TA < +125°C 60 μA
DYNAMIC PERFORMANCE
Slew Rate SR RL = 10 kΩ 0.1 V/μs
Settling Time 0.1% tS G = ±1, 2 V step 23 μs
Gain Bandwidth Product GBP RL = 100 kΩ 400 kHz
R
L = 10 kΩ 316 kHz
Phase Margin ØO R
L = 10 kΩ, RL = 100 kΩ 70 Degrees
NOISE PERFORMANCE
Peak-to-Peak Noise en p-p 0.1 Hz to 10 Hz 2.3 3.5 μV
Voltage Noise Density en f = 1 kHz 25 nV/√Hz
f = 10 kHz 22 nV/√Hz
Current Noise Density in f = 1 kHz 0.05 pA/√Hz
Channel Separation CS f = 10 kHz −115 dB
f = 100 kHz −110 dB
AD8603/AD8607/AD8609
Rev. C | Page 4 of 16
VS = 1.8 V, VCM = VS/2, TA = 25°C, unless otherwise noted.
Table 2.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage VOS V
S = 3.3 V @ VCM = 0.5 V and 2.8 V 12 50 μV
−0.3 V < VCM < +1.8 V 40 300 μV
−40°C < TA < +85°C, −0.3 V < VCM < +1.8 V 500 μV
−40°C < TA < +125°C, −0.3 V < VCM < +1.7 V 700 μV
Offset Voltage Drift ∆VOS/∆T −40°C < TA < +125°C 1 4.5 μV/°C
Input Bias Current IB 0.2 1 pA
−40°C < TA < +85°C 50 pA
−40°C < TA < +125°C 500 pA
Input Offset Current IOS 0.1 0.5 pA
−40°C < TA < +85°C 50 pA
−40°C < TA < +125°C 250 pA
Input Voltage Range IVR −0.3 +1.8 V
Common-Mode Rejection Ratio CMRR 0 V < VCM < 1.8 V 80 98 dB
−40°C < TA < +85°C 70 dB
Large Signal Voltage Gain AVO R
L = 10 kΩ, 0.5 V < VO < 4.5 V
AD8603 150 3000 V/mV
AD8607/AD8609 100 2000 V/mV
Input Capacitance CDIFF 2.1 pF
C
CM 3.8 pF
OUTPUT CHARACTERISTICS
Output Voltage High VOH I
L = 1 mA 1.65 1.72 V
−40°C to +125°C 1.6 V
Output Voltage Low VOL I
L = 1 mA 38 60 mV
−40°C to +125°C 80 mV
Short-Circuit Current ISC ±10 mA
Closed-Loop Output Impedance ZOUT f = 10 kHz, AV = 1 36 Ω
POWER SUPPLY
Power Supply Rejection Ratio PSRR 1.8 V < VS < 5 V 80 100 dB
Supply Current per Amplifier ISY V
O = 0 V 40 50 μA
−40°C < TA < +85°C 60 μA
DYNAMIC PERFORMANCE
Slew Rate SR RL = 10 kΩ 0.1 V/μs
Settling Time 0.1% tS G = ±1, 1 V step 9.2 μs
Gain Bandwidth Product GBP RL = 100 kΩ 385 kHz
R
L = 10 kΩ 316 kHz
Phase Margin ØO R
L = 10 kΩ, RL = 100 kΩ 70 Degrees
NOISE PERFORMANCE
Peak-to-Peak Noise en p-p 0.1 Hz to 10 Hz 2.3 3.5 μV
Voltage Noise Density en f = 1 kHz 25 nV/√Hz
f = 10 kHz 22 nV/√Hz
Current Noise Density in f = 1 kHz 0.05 pA/√Hz
Channel Separation CS f = 10 kHz −115 dB
f = 100 kHz −110 dB
AD8603/AD8607/AD8609
Rev. C | Page 5 of 16
ABSOLUTE MAXIMUM RATINGS
Absolute maximum ratings apply at 25°C, unless otherwise noted.
Table 3.
Parameter Rating
Supply Voltage 6 V
Input Voltage GND to VS
Differential Input Voltage ±6 V
Output Short-Circuit Duration to GND Indefinite
Storage Temperature Range −65°C to +150°C
Lead Temperature (Soldering, 60 sec) 300°C
Operating Temperature Range −40°C to +125°C
Junction Temperature Range −65°C to +150°C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent 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 affect device reliability.
Table 4. Package Characteristics
Package Type θJA1 θ
JC Unit
5-Lead TSOT (UJ) 207 61 °C/W
8-Lead MSOP (RM) 210 45 °C/W
8-Lead SOIC_N (R) 158 43 °C/W
14-Lead SOIC_N (R) 120 36 °C/W
14-Lead TSSOP (RU) 180 35 °C/W
1 θJA is specified for the worst-case conditions, that is, θJA is specified for a
device soldered in a circuit board for surface-mount packages.
ESD CAUTION
AD8603/AD8607/AD8609
Rev. C | Page 6 of 16
TYPICAL PERFORMANCE CHARACTERISTICS
V
OS
(µV)
NUMBER OF AMPLIFIERS
–210
0
400
800
1200
0150
200
600
1000
–150 –30 30 90 210 270–90
1600
1400
–270
1800
2000
2200
2400
2600
V
S
= 5V
T
A
= 25°C
V
CM
= 0V TO 5V
04356-006
Figure 6. Input Offset Voltage Distribution
TCVOS (µV/°C)
NUMBERS OF AMPLIFIERS
0
0
10
20
30
1.6 3.2
5
15
25
0.4 0.8 1.2 2.0 2.4 2.8 3.6 4.0 4.4 4.8 5.2
V
S
= ±2.5V
T
A
= –40°C TO +125°C
V
CM
= 0V
04356-007
Figure 7. Input Offset Voltage Drift Distribution
V
CM
(V)
V
OS
(µV)
0
–300
–100
100
300
1.5 3.5 5.0
1.00.5 2.5 4.54.03.02.0
–200
–150
–250
–50
0
50
150
200
250
04356-008
V
S
= 5V
T
A
= 25°C
Figure 8. Input Offset Voltage vs. Common-Mode Voltage
V
CM
(V)
V
OS
(µV)
0
–300
–100
100
300
0.9 2.1 3.0
0.60.3 1.5 2.72.41.81.2
–200
–150
–250
–50
0
50
150
200
250
3.3
V
S
= 3.3V
T
A
= 25°C
04356-009
V
CM
(V)
Figure 9. Input Offset Voltage vs. Common-Mode Voltage
TEMPERATURE (°C)
INPUT BIAS CURRENT (pA)
0
0
150
300
400
50 100 125
25 75
100
50
350
250
200
VS = ±2.5V
0
4356-010
Figure 10. Input Bias Current vs. Temperature
LOAD CURRENT (mA)
OUTPUT VOLTAGE TO SUPPLY RAIL (mV)
0.001
0.01
0.1
10
100
0.01 0.1 1 10
1000
1
04356-011
V
S
= 5V
T
A
= 25°C
SOURCE SINK
Figure 11. Output Voltage to Supply Rail vs. Load Current
AD8603/AD8607/AD8609
Rev. C | Page 7 of 16
TEMPERATURE (°C)
OUTPUT VOLTAGE SWING (mV)
–40
0
50
100
350
–25 –10 125
20 35 50 65 80 95 1105
150
250
300
200
V
OL
@ 1mA LOAD
V
DD
– V
OH
@ 1mA LOAD
V
DD
– V
OH
@ 10mA LOAD
V
OL
@ 10mA LOAD
V
S
= 5V
T
A
= 25°C
04356-012
Figure 12. Output Voltage Swing vs. Temperature
V
S
= ±2.5V
R
L
= 100kΩ
C
L
= 20pF
Φ = 70.9°
1k 10k 100k 1M 10M
FREQUENCY (Hz)
PHASE (Degree)
OPEN-LOOP GAIN (dB)
20
–80
–20
80
100
60
40
0
–40
–60
–100
45
–180
–45
180
225
135
90
0
–90
–135
–225
04356-013
Figure 13. Open-Loop Gain and Phase vs. Frequency
FREQUENCY (kHz)
OUTPUT VOLTAGE SWING (V p-p)
0.01
0
0.5
4.0
5.0
0.1 1 100
4.5
3.5
3.0
2.0
2.5
1.5
1.0
10
V
S
= 5V
V
IN
= 4.9V p-p
T
A
= 25°C
A
V
= 1
04356-014
Figure 14. Closed-Loop Output Voltage Swing vs. Frequency
V
S
= ±2.5V, ±0.9V
A
V
= 100
A
V
= 10
A
V
= 1
FREQUENCY (Hz)
OUTPUT IMPEDANCE (Ω)
100
175
350
1575
0
1k 100k
1750
1400
1225
875
1050
700
525
10k
04356-015
Figure 15. Output Impedance vs. Frequency
FREQUENCY (Hz)
CMRR (dB)
100
–60
–40
100
140
1k 10k
120
80
60
20
40
0
–20
100k
V
S
= ±2.5V
04356-016
Figure 16. CMRR vs. Frequency
10 100 1k 10k 100k
FREQUENCY (Hz)
PSRR (dB)
0
140
–40
–60
–20
20
60
40
80
120
100
04356-017
V
S
= ±2.5V
Figure 17. PSRR vs. Frequency
AD8603/AD8607/AD8609
Rev. C | Page 8 of 16
LOAD CAPACITANCE (pF)
SMALL SIGN
A
L OVERSHOOT (%)
10
0
10
20
100 1000
30
OS–
50
40
V
S
= 5V
04356-018
60
OS+
Figure 18. Small Signal Overshoot vs. Load Capacitance
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
–40
35
20 80–25 50
60
–10 5 35 65
10
0
95 110 125
25
50
55
45
40
30
20
15
5
V
S
= ±2.5V
0
4356-019
Figure 19. Supply Current vs. Temperature
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (µA)
0
0
30
60
80
2453
20
10
70
50
40
1
100
90
04356-020
T
A
= 25°C
Figure 20. Supply Current vs. Supply Voltage
V
S
= 5V, 1.8V
TIME (1s/DIV)
VOLTAGE NOISE (1µV/DIV)
04356-021
Figure 21. 0.1 Hz to 10 Hz Input Voltage Noise
V
S
= 5V
R
L
= 10kΩ
C
L
= 200pF
A
V
= 1
TIME (4µs/DIV)
VOL
T
AGE (50mV/DIV)
04356-022
Figure 22. Small Signal Transient
TIME (20µs/DIV)
VOL
T
AGE (1V/DIV)
04356-023
VS = 5V
RL = 10kΩ
CL = 200pF
AV = 1
Figure 23. Large Signal Transient
AD8603/AD8607/AD8609
Rev. C | Page 9 of 16
V
S
= ±2.5V
R
L
= 10kΩ
A
V
= 100
V
IN
= 50mV
0V
0V
–50mV
+2.5V
TIME (4
μ
s/DIV))
V
IN
(mV) V
OUT
(V)
TIME (40µs/DIV)
04356-024
Figure 24. Negative Overload Recovery
VS = ±2.5V
RL = 10kΩ
AV = 100
VIN = 50mV
0V
0V
–50mV
+2.5V
TIME (4µs/DIV)
04356-025
VIN (mV) VOUT (V)
Figure 25. Positive Overload Recovery
FREQUENCY (kHz)
VOLTAGE NOISE DENSITY (nV/
√
Hz)
24
0.1 1.00.2 0.3 0.4 0.5 0.6 0.7 0.8 0.90
48
72
96
120
144
168
0
V
S
= ±2.5V
04356-026
Figure 26. Voltage Noise Density vs. Frequency
FREQUENCY (kHz)
VOLTAGE NOISE DENSITY (nV/
√
Hz)
22
11234567890
44
66
88
110
132
176
0
0
V
S
= ±2.5V
154
04356-027
Figure 27. Voltage Noise Density vs. Frequency
V
OS
(µV)
NUMBER OF AMPLIFIERS
–300
0
300
500
800
–240 60 240
–180 –120 120 180 300
400
200
100
700
600
0
–60
50
150
250
350
450
550
650
750 V
S
= 1.8V
T
A
= 25°C
V
CM
= 0V TO 1.8V
04356-028
Figure 28. VOS Distribution
V
CM
(V)
V
OS
(µV)
0
–300
–100
100
300
0.9
0.60.3 1.5 1.81.2
–200
–150
–250
–50
0
50
150
200
250 V
S
= 1.8V
T
A
= 25°C
04356-029
V
CM
(V)
Figure 29. Input Offset Voltage vs. Common-Mode Voltage
AD8603/AD8607/AD8609
Rev. C | Page 10 of 16
LOAD CURRENT (mA)
OUTPUT VOLTAGE TO SUPPLY RAIL (mV)
0.001
0.01
0.1
10
100
0.01 0.1 1 10
1000
1
SINK
SOURCE
VS = 1.8V
TA = 25°C
04356-030
Figure 30. Output Voltage to Supply Rail vs. Load Current
TEMPERATURE (°C)
OUTPUT VOLTAGE SWING (mV)
–40
0
30
60
535 125
20
20
10
50
40
–25
70
80
90
100
–10 50 65 80 95 110
VOL @ 1mA LOAD
VDD – VOH @ 1mA LOAD
VS = 1.8V
04356-031
Figure 31. Output Voltage Swing vs. Temperature
LOAD CAPACITANCE (pF)
SMALL SIGN
A
L OVERSHOOT (%)
10
0
10
20
60
100 1000
30
50
40
VS = 1.8V
TA = 25°C
AV = 1
OS–
OS+
04356-032
Figure 32. Small Signal Overshoot vs. Load Capacitance
1k 10k 100k 1M 10M
VS = ±0.9V
RL = 100kΩ
CL = 20pF
Φ = 70°
FREQUENCY (Hz)
PHASE (Degrees)
OPEN-LOOP GAIN (dB)
20
–80
–20
80
100
60
40
0
–40
–60
–100
45
–180
–45
180
225
135
90
0
–90
–135
–225
04356-033
Figure 33. Open-Loop Gain and Phase vs. Frequency
100 1k 10k 100k
V
S
= 1.8V
CMRR (dB)
60
–40
20
120
140
100
80
40
0
–20
–60
FREQUENCY (Hz)
04356-034
Figure 34. CMRR vs. Frequency
0.01 0.1 1 10010
FREQUENCY (kHz)
OUTPUT VOLTAGE SWING (V p-p)
0
0.9
1.8
0.6
0.3
1.5
1.2
V
S
= 1.8V
V
IN
= 1.7V p-p
T
A
= 25°C
A
V
= 1
04356-035
Figure 35. Closed-Loop Output Voltage Swing vs. Frequency
AD8603/AD8607/AD8609
Rev. C | Page 11 of 16
V
S
= 1.8V
R
L
= 10kΩ
C
L
= 200pF
A
V
= 1
VOLTAGE (50mV/DIV)
TIME (4µs/DIV)
04356-036
Figure 36. Small Signal Transient
V
S
= 1.8V
R
L
= 10kΩ
C
L
= 200pF
A
V
= 1
VOLTAGE (500mV/DIV)
TIME (20µs/DIV)
04356-037
Figure 37. Large Signal Transient
FREQUENCY (kHz)
VOLTAGE NOISE DENSITY (nV/
√
Hz)
28
0.1 1.00.2 0.3 0.4 0.5 0.6 0.7 0.8 0.90
56
84
112
140
168
0
V
S
= ±0.9V
04356-038
Figure 38. Voltage Noise Density vs. Frequency
FREQUENCY (kHz)
VOLTAGE NOISE DENSITY (nV/
√
Hz)
22
11234567890
44
66
88
110
132
176
0
0
V
S
= ±0.9V
154
04356-039
Figure 39. Voltage Noise Density vs. Frequency
FREQUENCY (Hz)
CHANNEL SEPA
TION (dB)
100
–120
–40
–20
0
1k 10k 100k 1M
–60
–140
–80
–100
V
S
= ±2.5V, ±0.9V
04356-040
Figure 40. Channel Separation vs. Frequency
AD8603/AD8607/AD8609
Rev. C | Page 12 of 16
APPLICATIONS
NO PHASE REVERSAL
The AD8603/AD8607/AD8609 do not exhibit phase inversion
even when the input voltage exceeds the maximum input
common-mode voltage. Phase reversal can cause permanent
damage to the amplifier, resulting in system lockups. The
AD8603/AD8607/AD8609 can handle voltages of up to 1 V
over the supply.
VOLTAGE (1V/DIV)
TIME (4µs/DIV)
V
S
= ±2.5V
V
IN
= 6V p-p
A
V
= 1
R
L
= 10kΩ
V
IN
V
OUT
04356-041
Figure 41. No Phase Response
INPUT OVERVOLTAGE PROTECTION
If a voltage 1 V higher than the supplies is applied at either
input, the use of a limiting series resistor is recommended. If
both inputs are used, each one should be protected with a
series resistor.
To ensure good protection, the current should be limited to a
maximum of 5 mA. The value of the limiting resistor can be
determined from the following equation:
(VIN − VS)/(RS + 200 Ω) ≤ 5 mA
DRIVING CAPACITIVE LOADS
The AD8603/AD8607/AD8609 are capable of driving large
capacitive loads without oscillating. Figure 42 shows the output
of the AD8603/AD8607/AD8609 in response to a 100 mV input
signal, with a 2 nF capacitive load.
Although it is configured in positive unity gain (the worst case),
the AD8603 shows less than 20% overshoot. Simple additional
circuitry can eliminate ringing and overshoot.
One technique is the snubber network, which consists of a
series RC and a resistive load (see Figure 43). With the snubber
in place, the AD8603/AD8607/AD8609 are capable of driving
capacitive loads of 2 nF with no ringing and less than 3%
overshoot.
The use of the snubber circuit is usually recommended for unity
gain configurations. Higher gain configurations help improve
the stability of the circuit. Figure 44 shows the same output
response with the snubber in place.
V
S
= ±0.9V
V
IN
= 100mV
C
L
= 2nF
R
L
= 10kΩ
0
4356-042
Figure 42. Output Response to a 2 nF Capacitive Load, Without Snubber
04356-043
C
S
47pF
V
CC
V
EE
R
S
150Ω
200mV
C
L
V+
V–
–
+
Figure 43. Snubber Network
V
SY
= ±0.9V
V
IN
= 100mV
C
L
= 2nF
R
L
= 10kΩ
R
S
= 150Ω
C
S
= 470pF
04356-044
Figure 44. Output Response to a 2 nF Capacitive Load with Snubber
Optimum values for RS and CS are determined empirically;
Table 5 lists a few starting values.
Table 5. Optimum Values for the Snubber Network
CL (pF) RS (Ω)
CS (pF)
100 to ~500 500 680
1500 100 330
1600 to ~2000 400 100
AD8603/AD8607/AD8609
Rev. C | Page 13 of 16
PROXIMITY SENSORS
Proximity sensors can be capacitive or inductive and are used in
a variety of applications. One of the most common applications
is liquid level sensing in tanks. This is particularly popular in
pharmaceutical environments where a tank must know when to
stop filling or mixing a given liquid. In aerospace applications,
these sensors detect the level of oxygen used to propel engines.
Whether in a combustible environment or not, capacitive
sensors generally use low voltage. The precision and low voltage
of the AD8603/AD8607/AD8609 make the parts an excellent
choice for such applications.
COMPOSITE AMPLIFIERS
A composite amplifier can provide a very high gain in applications
where high closed-loop dc gains are needed. The high gain
achieved by the composite amplifier comes at the expense of a
loss in phase margin. Placing a small capacitor, CF, in the feedback
in parallel with R2 (see Figure 45) improves the phase margin.
Picking CF = 50 pF yields a phase margin of about 45° for the
values shown in Figure 45.
V
EE
V
CC
R1
C
F
1kΩ
V
CC
V
EE
V
IN
99kΩ
R2
AD8603
AD8541
V+
V
–
V+
V
–
R3 R4
99kΩ1kΩ
U5
04356-045
Figure 45. High Gain Composite Amplifier
A composite amplifier can be used to optimize dc and ac
characteristics. Figure 46 shows an example using the AD8603
and the AD8541. This circuit offers many advantages. The band-
width is increased substantially, and the input offset voltage and
noise of the AD8541 become insignificant because they are divided
by the high gain of the AD8603.
The circuit in Figure 46 offers high bandwidth (nearly double
that of the AD8603), high output current, and very low power
consumption of less than 100 μA.
R1
1kΩ
V+
V
–
V
IN
100kΩ
R2
AD8541
100Ω
C3
1kΩ
R4
R3
C2
V
CC
V
EE
04356-046
V
CC
V
EE
V–
V+
AD8603
Figure 46. Low Power Composite Amplifier
BATTERY-POWERED APPLICATIONS
The AD8603/AD8607/AD8609 are ideal for battery-powered
applications. The parts are tested at 5 V, 3.3 V, 2.7 V, and 1.8 V
and are suitable for various applications whether in single or
dual supply.
In addition to their low offset voltage and low input bias, the
AD8603/AD8607/AD8609 have a very low supply current of
40 μA, making the parts an excellent choice for portable electronics.
The TSOT package allows the AD8603 to be used on smaller
board spaces.
PHOTODIODES
Photodiodes have a wide range of applications from barcode
scanners to precision light meters and CAT scanners. The very
low noise and low input bias current of the AD8603/AD8607/
AD8609 make the parts very attractive amplifiers for I-V
conversion applications.
Figure 47 shows a simple photodiode circuit. The feedback
capacitor helps the circuit maintain stability. The signal band-
width can be increased at the expense of an increase in the total
noise; a low-pass filter can be implemented by a simple RC network
at the output to reduce the noise. The signal bandwidth can be
calculated by ½πR2C2, and the closed-loop bandwidth is the
intersection point of the open-loop gain and the noise gain.
The circuit shown in Figure 47 has a closed-loop bandwidth of
58 kHz and a signal bandwidth of 16 Hz. Increasing C2 to 50 pF
yields a closed-loop bandwidth of 65 kHz, but only 3.2 Hz of
signal bandwidth can be achieved.
C2
10pF
R2
1000MΩ
R1
1000MΩ
V
CC
V
EE
V–
V+
AD8603
C1
10pF
04356-047
Figure 47. Photodiode Circuit
AD8603/AD8607/AD8609
Rev. C | Page 14 of 16
OUTLINE DIMENSIONS
*COMPLIANT TO JEDEC STANDARDS MO-193-AB WITH
THE EXCEPTION OF PACKAGE HEIGHT AND THICKNESS.
PIN 1
1.60 BSC 2.80 BSC
1.90
BSC
0.95 BSC
0.20
0.08
0.60
0.45
0.30
8°
4°
0°
0.50
0.30
0.10 MAX SEATING
PLANE
*1.00 MAX
*0.90
0.87
0.84
2.90 BSC
54
123
Figure 48. 5-Lead Thin Small Outline Transistor Package [TSOT]
(UJ-5)
Dimensions shown in millimeters
COMPLIANT TO JEDEC STANDARDS MO-187-AA
0.80
0.60
0.40
8°
0°
4
8
1
5
PIN 1
0.65 BSC
SEATING
PLANE
0.38
0.22
1.10 MAX
3.20
3.00
2.80
COPLANARITY
0.10
0.23
0.08
3.20
3.00
2.80
5.15
4.90
4.65
0.15
0.00
0.95
0.85
0.75
Figure 49. 8-Lead Mini Small Outline Package [MSOP]
(RM-8)
Dimensions shown in millimeters
AD8603/AD8607/AD8609
Rev. C | Page 15 of 16
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
COMPLIANT TO JEDEC STANDARDS MS-012-A A
012407-A
0.25 (0.0098)
0.17 (0.0067)
1.27 (0.0500)
0.40 (0.0157)
0.50 (0.0196)
0.25 (0.0099) 45°
8°
0°
1.75 (0.0688)
1.35 (0.0532)
SEATING
PLANE
0.25 (0.0098)
0.10 (0.0040)
4
1
85
5.00 (0.1968)
4.80 (0.1890)
4.00 (0.1574)
3.80 (0.1497)
1.27 (0.0500)
BSC
6.20 (0.2441)
5.80 (0.2284)
0.51 (0.0201)
0.31 (0.0122)
COPLANARITY
0.10
Figure 50. 8-Lead Standard Small Outline Package [SOIC_N]
(R-8)
Dimensions shown in millimeters and (inches)
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
COMPLIANT TO JEDEC STANDARDS MS-012-AB
060606-A
14 8
7
1
6.20 (0.2441)
5.80 (0.2283)
4.00 (0.1575)
3.80 (0.1496)
8.75 (0.3445)
8.55 (0.3366)
1.27 (0.0500)
BSC
SEATING
PLANE
0.25 (0.0098)
0.10 (0.0039)
0.51 (0.0201)
0.31 (0.0122)
1.75 (0.0689)
1.35 (0.0531)
0.50 (0.0197)
0.25 (0.0098)
1.27 (0.0500)
0.40 (0.0157)
0.25 (0.0098)
0.17 (0.0067)
COPLANARITY
0.10
8°
0°
45°
Figure 51. 14-Lead Standard Small Outline Package [SOIC_N]
(R-14)
Dimensions shown in millimeters and (inches)
4.50
4.40
4.30
14 8
71
6.40
BSC
PIN 1
5.10
5.00
4.90
0.65
BSC
SEATING
PLANE
0.15
0.05 0.30
0.19
1.20
MAX
1.05
1.00
0.80 0.20
0.09
8°
0°
0.75
0.60
0.45
COPLANARITY
0.10
COMPLIANT TO JEDEC STANDARDS MO-153-AB-1
Figure 52. 14-Lead Thin Shrink Small Outline Package [TSSOP]
(RU-14)
Dimensions shown in millimeters
AD8603/AD8607/AD8609
Rev. C | Page 16 of 16
ORDERING GUIDE
Model Temperature Range Package Description Package Option Branding
AD8603AUJ-R2 −40°C to +125°C 5-Lead TSOT UJ-5 BFA
AD8603AUJ-REEL −40°C to +125°C 5-Lead TSOT UJ-5 BFA
AD8603AUJ-REEL7 −40°C to +125°C 5-Lead TSOT UJ-5 BFA
AD8603AUJZ-R21
−40°C to +125°C 5-Lead TSOT UJ-5 A0X
AD8603AUJZ-REEL1
−40°C to +125°C 5-Lead TSOT UJ-5 A0X
AD8603AUJZ-REEL71
−40°C to +125°C 5-Lead TSOT UJ-5 A0X
AD8607ARM-R2 −40°C to +125°C 8-Lead MSOP RM-8 A00
AD8607ARM-REEL −40°C to +125°C 8-Lead MSOP RM-8 A00
AD8607ARMZ-R21
−40°C to +125°C 8-Lead MSOP RM-8 A0G
AD8607ARMZ-REEL1
−40°C to +125°C 8-Lead MSOP RM-8 A0G
AD8607AR −40°C to +125°C 8-Lead SOIC_N R-8
AD8607AR-REEL −40°C to +125°C 8-Lead SOIC_N R-8
AD8607AR-REEL7 −40°C to +125°C 8-Lead SOIC_N R-8
AD8607ARZ1
−40°C to +125°C 8-Lead SOIC_N R-8
AD8607ARZ-REEL1
−40°C to +125°C 8-Lead SOIC_N R-8
AD8607ARZ-REEL71
−40°C to +125°C 8-Lead SOIC_N R-8
AD8609AR −40°C to +125°C 14-Lead SOIC_N R-14
AD8609AR-REEL −40°C to +125°C 14-Lead SOIC_N R-14
AD8609AR-REEL7 −40°C to +125°C 14-Lead SOIC_N R-14
AD8609ARZ1
−40°C to +125°C 14-Lead SOIC_N R-14
AD8609ARZ-REEL1
−40°C to +125°C 14-Lead SOIC_N R-14
AD8609ARZ-REEL71
−40°C to +125°C 14-Lead SOIC_N R-14
AD8609ARU −40°C to +125°C 14-Lead TSSOP RU-14
AD8609ARU-REEL −40°C to +125°C 14-Lead TSSOP RU-14
AD8609ARUZ1
−40°C to +125°C 14-Lead TSSOP RU-14
AD8609ARUZ-REEL1
−40°C to +125°C 14-Lead TSSOP RU-14
1 Z = RoHS Compliant Part.
©2003–2008 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D04356-0-6/08(C)