AD AD8609ARU

Precision Micropower Low Noise CMOS Railto-Rail Input/Output Operational Amplifiers
AD8603/AD8607/AD8609
GENERAL DESCRIPTION
The AD8603/AD8607/AD8609 are, single/dual/quad micropower rail-to-rail input and output amplifiers, respectively, that
features 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 make 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-23 package. The
AD8607 is available in 8-lead MSOP and SOIC packages. The
AD8609 is available in 14-lead TSSOP and SOIC packages.
5
V+
4
–IN
AD8603
+IN 3
TOP VIEW
(Not to Scale)
04356-0-001
V– 2
Figure 1. 5-Lead TSOT-23 (UJ Suffix)
OUT A
–IN A
+IN A
V–
1
8
V+
OUT B
–IN B
+IN B
AD8607
4
5
04356-0-045
Battery-powered instrumentation
Multipole filters
Sensors
Low power ASIC input or output amplifiers
OUT 1
Figure 2. 8-Lead MSOP (RM Suffix)
OUT A 1
8 V+
–IN A 2
7 OUT B
AD8607
+IN A 3
6 –IN B
V– 4
5 +IN B
04356-0-047
APPLICATIONS
PIN CONFIGURATIONS
Figure 3. 8-Lead SOIC (R Suffix)
OUT A
–IN A
+IN A
V+
+IN B
–IN B
OUT B
1
14
AD8609
8
7
OUT D
–IN D
+IN D
V–
+IN C
–IN C
OUT C
04356-0-044
Low offset voltage: 50 µV max
Low input bias current: 1 pA max
Single-supply operation: 1.8 V to 5 V
Low noise: 22 nV/√Hz
Micropower: 50 µA max
Low distortion
No phase reversal
Unity gain stable
Figure 4. 14-Lead TSSOP (RU Suffix)
14 OUT D
OUT A 1
–IN A 2
13 –IN D
+IN A 3
V+ 4
12 +IN D
AD8609
11 V–
+IN B 5
10 +IN C
–IN B 6
9 –IN C
OUT B 7
8 OUT C
04356-0-046
FEATURES
Figure 5. 14-Lead SOIC (R Suffix)
Rev. A
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.326.8703
© 2003 Analog Devices, Inc. All rights reserved.
AD8603/AD8607/AD8609
TABLE OF CONTENTS
Specifications..................................................................................... 3
Proximity Sensors....................................................................... 13
Absolute Maximum Ratings............................................................ 5
Composite Amplifiers................................................................ 13
Typical Performance Characteristics ............................................. 6
Battery-Powered Applications .................................................. 14
Applications..................................................................................... 12
Photodiodes ................................................................................ 14
No Phase Reversal ...................................................................... 12
Outline Dimensions ....................................................................... 15
Input Overvoltage Protection ................................................... 12
Ordering Guide .......................................................................... 16
Driving Capacitive Loads .......................................................... 12
REVISION HISTORY
10/03—Data Sheet Changed from Rev. 0 to Rev. A
Change
Page
Added AD8607 and AD8609 parts ..............................Universal
Changes to Specifications ............................................................ 3
Changes to Figure 35.................................................................. 10
Added Figure 41.......................................................................... 11
Rev. A | Page 2 of 16
AD8603/AD8607/AD8609
SPECIFICATIONS
Table 1. Electrical Characteristics @ VS = 5 V, VCM = VS/2, TA = 25°C, unless otherwise noted
Parameter
INPUT CHARACTERISTICS
Offset Voltage
Offset Voltage Drift
Input Bias Current
Symbol
Conditions
VOS
VS = 3.3 V @ VCM = 0.5 V and 2.8 V
–0.3 V < VCM < +5.2 V
–40°C < TA < +125°C, –0.3 V < VCM < +5.2 V
–40°C < TA < +125°C
∆VOS/∆T
IB
Min
Typ
Max
Unit
12
40
50
300
700
4.5
1
50
500
0.5
50
250
+5.2
µV
µV
µV
µV/°C
pA
pA
pA
pA
pA
pA
V
dB
dB
1
0.2
–40°C < TA < +85°C
–40°C < TA < +125°C
Input Offset Current
IOS
0.1
–40°C < TA < +85°C
–40°C < TA < +125°C
Input Voltage Range
Common-Mode Rejection Ratio
IVR
CMRR
Large Signal Voltage Gain
AD8603
AD8607/AD8609
Input Capacitance
AVO
OUTPUT CHARACTERISTICS
Output Voltage High
Output Voltage Low
Output Current
Closed-Loop Output Impedance
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current/Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Settling Time 0.1%
Gain Bandwidth Product
0 V < VCM < 5 V
–40°C < TA < +125°C
RL = 10 kΩ, 0.5 V <VO < 4.5 V
–0.3
85
80
400
250
1000
450
1.9
2.5
V/mV
V/mV
pF
pF
4.95
4.9
4.65
4.50
4.97
V
V
V
V
mV
mV
mV
mV
mA
Ω
CDIFF
CCM
VOH
VOL
IOUT
ZOUT
IL = 1 mA
–40°C to +125°C
IL = 10 mA
–40°C to +125°C
IL = 1 mA
–40°C to +125°C
IL = 10 mA
–40°C to +125°C
100
4.97
16
160
±80
36
f = 10 kHz, AV = 1
PSRR
ISY
1.8 V < VS < 5 V
VO = 0 V
–40°C <TA < +125°C
SR
tS
GBP
RL = 10 kΩ
G= ±1, 2 V Step
RL = 100 kΩ
RL = 10 kΩ
RL = 10 kΩ, RL = 100 kΩ
0.1
23
400
316
70
0.1 Hz to 10 Hz
f = 1 kHz
f = 10 kHz
f = 1 kHz
f = 10 kHz
f = 100 kHz
2.3
25
22
0.05
–115
–110
Phase Margin
NOISE PERFORMANCE
Peak-to-Peak Noise
Voltage Noise Density
ØO
Current Noise Density
Channel Separation
in
Cs
en p-p
en
Rev. A | Page 3 of 16
30
50
250
330
80
100
40
50
60
dB
µA
µA
V/µs
µs
kHz
kHz
Degrees
3.5
µV
nV/√Hz
nV/√Hz
pA/√Hz
dB
dB
AD8603/AD8607/AD8609
Table 2. Electrical Characteristics @ VS = 1.8 V, VCM = VS/2, TA = 25°C, unless otherwise noted
Parameter
INPUT CHARACTERISTICS
Offset Voltage
Offset Voltage Drift
Input Bias Current
Symbol
Conditions
VOS
VS = 3.3 V @ VCM = 0.5 V and 2.8 V
–0.3 V < VCM < +1.8 V
–40°C < TA < +85°C, –0.3 V < VCM < +1.8 V
–40°C < TA < +125°C, –0.3 V < VCM < +1.7 V
–40°C < TA < +125°C
∆VOS/∆T
IB
Min
Typ
Max
Unit
12
40
50
300
500
700
4.5
1
50
500
0.5
50
250
+1.8
µV
µV
µV
µV
µV/°C
pA
pA
pA
pA
pA
pA
V
dB
dB
1
0.2
–40°C < TA < +85°C
–40°C < TA < +125°C
Input Offset Current
IOS
0.1
–40°C < TA < +85°C
–40°C < TA < +125°C
Input Voltage Range
Common-Mode Rejection Ratio
IVR
CMRR
Large Signal Voltage Gain
AD8603
AD8607/AD8609
Input Capacitance
AVO
OUTPUT CHARACTERISTICS
Output Voltage High
Output Voltage Low
Output Current
Closed-Loop Output Impedance
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current/Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Settling Time 0.1%
Gain Bandwidth Product
Phase Margin
NOISE PERFORMANCE
Peak-to-Peak Noise
Voltage Noise Density
0 V < VCM < 1.8 V
–40°C < TA < +85°C
RL = 10 kΩ, 0.5 V <VO < 4.5 V
–0.3
80
70
150
100
3000
2000
2.1
3.8
V/mV
V/mV
pF
pF
1.65
1.6
1.72
V
V
mV
mV
mA
Ω
CDIFF
CCM
VOH
VOL
IOUT
ZOUT
IL = 1 mA
–40°C to +125°C
IL = 1 mA
–40°C to +125°C
98
38
±7
36
f = 10 kHz, AV = 1
PSRR
ISY
1.8 V < VS < 5 V
VO = 0 V
–40°C < TA < +85°C
SR
tS
GBP
RL = 10 kΩ
G= ±1, 1 V Step
RL = 100 kΩ
RL = 10 kΩ
RL = 10 kΩ, RL = 100 kΩ
0.1
9.2
385
316
70
0.1 Hz to 10 Hz
f = 1 kHz
f = 10 kHz
f = 1 kHz
2.3
25
22
0.05
f = 10 kHz
f = 100 kHz
–115
–110
ØO
en p-p
en
Current Noise Density
in
Channel Separation
Cs
Rev. A | Page 4 of 16
60
80
80
100
40
50
60
dB
µA
µA
V/µs
µs
kHz
kHz
Degrees
3.5
µV
nV/√Hz
nV/√Hz
pA/√Hz
dB
dB
AD8603/AD8607/AD8609
ABSOLUTE MAXIMUM RATINGS
Table 3. AD8603/AD8607/AD8609 Stress Ratings1, 2
Table 4. Package Characteristics
Parameter
Supply Voltage
Input Voltage
Differential Input Voltage
Output Short-Circuit Duration to GND
Storage Temperature Range
All Packages
Lead Temperature Range (Soldering, 60 Sec)
Operating Temperature Range
Junction Temperature Range
All Packages
Package Type
5-Lead TSOT-23 (UJ)
8-Lead MSOP (RM)
8-Lead SOIC (R)
14-Lead SOIC (R)
14-Lead TSSOP (RU)
Rating
6V
GND to VS
±6 V
Indefinite
–65°C to +150°C
300°C
–40°C to +125°C
–65°C to +150°C
1
θJA3
207
210
158
120
180
θJC
61
45
43
36
35
Unit
°C/W
°C/W
°C/W
°C/W
°C/W
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 listed
in the operational sections of this specification is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device
reliability.
2
Absolute maximum ratings apply at 25°C, unless otherwise noted.
3
θJA is specified for the worst-case conditions, i.e., θJA is specified for device
soldered in circuit board for surface-mount packages.
ESD 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 these parts feature
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.
Rev. A | Page 5 of 16
AD8603/AD8607/AD8609
TYPICAL PERFORMANCE CHARACTERISTICS
2600
300
VS = 5V
TA = 25°C
VCM = 0V to 5V
2400
2200
200
150
1800
100
1600
50
1400
VOS (µV)
1200
1000
–100
800
–150
600
200
–270 –210 –150 –90
–30 0 30
VOS (µV)
90
150
210
–250
–300
0.0
270
Figure 6. Input Offset Voltage Distribution
0.6
0.9
1.2
1.5 1.8
VCM (V)
(V)
2.1
2.4
2.7
3.0
3.3
400
350
VS = ±2.5V
20
INPUT BIAS CURRENT (pA)
VS= ±2.5V
TA= –40°C TO +125°C
VCM= 0V
15
10
04356-0-003
5
0
0.4 0.8 1.2 1.6
2.0 2.4 2.8 3.2 3.6
TCVOS (µV/°C)
300
250
200
150
100
04356-0-006
25
NUMBERS OF AMPLIFIERS
0.3
Figure 9. Input Offset Voltage vs. Common-Mode Voltage
30
50
0
4.0 4.4 4.8
0
Figure 7. Input Offset Voltage Drift Distribution
75
50
TEMPERATURE (°C)
100
125
1000
OUTPUT VOLTAGE TO SUPPLY RAIL (mV)
VS = 5V
TA = 25°C
200
150
100
50
0
–50
–100
–150
04356-0-004
–200
–250
–300
0.0
25
Figure 10. Input Bias vs. Temperature
300
250
VOS (µV)
04356-0-005
–200
04356-0-002
400
0
0
–50
0.5
1.0
1.5
2.0
2.5
3.0
VCM (V)
3.5
4.0
4.5
VS = 5V
TA = 25°C
100
10
SOURCE
1
0.1
0.01
0.001
5.0
SINK
04356-0-007
NUMBER OF AMPLIFIERS
2000
0
VS = 3.3V
TA = 25°C
250
0.01
0.1
LOAD CURRENT (mA)
1
Figure 11. Output Voltage to Supply Rail vs. Load Current
Figure 8. Input Offset Voltage vs. Common-Mode Voltage
Rev. A | Page 6 of 16
10
AD8603/AD8607/AD8609
1925
VS = 5V
TA = 25°C
1750
OUTPUT IMPEDANCE (Ω)
250
200
VOL @ 10mA LOAD
150
100
50
VDD – VOH @ 1mA LOAD
0
–40 –25
VOL @ 1mA LOAD
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
1400
1225
1050
700
175
100
125
225
140
180
120
135
100
90
20
45
0
0
–20
–45
–90
–60
–135
–80
–180
10k
100k
FREQUENCY (Hz)
–225
10M
1M
60
40
20
–20
–60
100
100k
1k
10k
FREQUENCY (Hz)
Figure 16. Common-Mode Rejection Ratio vs. Frequency
140
VS = 5V
VIN = 4.9V p-p
T = 25°C
AV = 1
100
60
PSRR (dB)
80
3.0
2.5
2.0
40
20
0
1.0
–20
04356-0-011
1.5
0.5
0.1
VS = ±2.5V
120
3.5
0.0
0.01
VS = ±2.5V
–40
5.0
4.0
100k
0
Figure 13. Open-Loop Gain and Phase vs. Frequency
4.5
10k
FREQUENCY (Hz)
1
FREQUENCY (kHz)
10
04356-0-014
–100
1k
1k
80
CMRR (dB)
40
–40
OUTPUT SWING (V p-p)
OPEN-LOOP GAIN (dB)
60
A=1
Figure 15. Output Impedance vs. Frequency
PHASE (Degree)
80
A = 10
350
04356-0-010
VS = ±2.5V
RL = 100kΩ
CL = 20pF
φ = 70.9°
A = 100
875
Figure 12. Output Voltage Swing vs. Temperature
100
VS = ±2.5V, ±0.9V
525
04356-0-008
OUTPUT SWING (mV)
1575
VDD – VOH @ 10mA LOAD
04356-0-012
300
04356-0-013
350
–40
–60
100
Figure 14. Closed-Loop Output Voltage Swing vs. Frequency
10
100
1k
FREQUENCY (Hz)
Figure 17. PSRR vs. Frequency
Rev. A | Page 7 of 16
10k
100k
AD8603/AD8607/AD8609
60
VS = 5V
VS = 5V, 1.8V
OS–
30
20
OS+
10
04356-0-018
VOLTAGE NOISE (1µV/DIV)
40
04356-0-015
SMALL SIGNAL OVERSHOOT (%)
50
0
10
100
LOAD CAPACITANCE (pF)
1000
TIME (1s/DIV)
Figure 18. Small Signal Overshoot vs. Load Capacitance
Figure 21. 0.1 Hz to 10 Hz Input Voltage Noise
60
55
VS = 5V
RL = 10kΩ
CL = 200pF
AV = 1
VS = ±2.5V
50
VOLTAGE (50mV/DIV)
40
35
30
25
20
15
04356-0-016
10
5
0
–40
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
04356-0-019
SUPPLY CURRENT (µA)
45
125
TIME (4µs/DIV)
Figure 19. Supply Current vs. Temperature
Figure 22. Small Signal Transient
100
90
VS = 5V
RL = 10kΩ
CL = 200pF
AV = 1
TA = 25°C
VOLTAGE (1V/DIV)
70
60
50
40
30
10
0
04356-0-020
20
04356-0-017
SUPPLY CURRENT (µA)
80
0
1.0
2.0
3.0
SUPPLY VOLTAGE (V)
4.0
5.0
TIME (20µs/DIV)
Figure 23. Large Signal Transient
Figure 20. Supply Current vs. Supply Voltage
Rev. A | Page 8 of 16
AD8603/AD8607/AD8609
VS = ±2.5V
0V
0V
04356-0-021
–50mV
154
132
110
88
66
44
04356-0-046
VOLTAGE NOISE DENSITY (nV/ Hz)
+2.5V
VOLTAGE (50mV/DIV)
176
VS = ±2.5V
RL = 10kΩ
AV = 100
VIN = 50mV
22
0
0
1
2
3
4
5
6
7
FREQUENCY (kHz)
8
9
10
TIME (4µs/DIV))
(40µs/DIV))
Figure 27. Voltage Noise Density vs. Frequency
Figure 24. Negative Overload Recovery
800
750
0V
04356-0-022
–50mV
VS = 1.8V
TA = 25°C
VCM = 0V to 1.8V
700
650
600
550
500
450
400
350
300
250
200
150
04356-0-025
NUMBER OF AMPLIFIERS
+2.5V
0V
100
50
0
–300 –240 –180 –120
TIME (4µs/DIV)
Figure 25. Positive Overload Recovery
–60
0
60
VOS (µV)
120
180
240
300
Figure 28. VOS Distribution
168
300
VS = ±2.5V
250
144
200
120
VS = 1.8V
TA = 25°C
150
100
96
VOS (µV)
50
72
48
–150
–200
04356-0-026
0
0
0
–50
–100
24
04356-0-045
VOLTAGE NOISE DENSITY (nV/ Hz)
VOLTAGE (50mV/DIV)
VS = ±2.5V
RL = 10kΩ
AV = 100
VIN = 50mV
–250
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
FREQUENCY (kHz)
–300
0.0
Figure 26. Voltage Noise Density vs. Frequency
0.3
0.6
0.9
V
VCM
(V)
CM(V)
1.2
1.5
Figure 29. Input Offset Voltage vs. Common-Mode Voltage
Rev. A | Page 9 of 16
1.8
AD8603/AD8607/AD8609
10
OPEN-LOOP GAIN (dB)
60
SOURCE
SINK
1
0.1
0.01
0.001
0.01
0.1
LOAD CURRENT (mA)
90
20
45
0
0
–20
–45
–40
–90
–60
–135
–80
–180
1
Figure 30. Output Voltage to Supply Rail vs. Load Current
–225
10M
1M
120
VS = 1.8V
80
70
100
VS = 1.8V
80
VDD – VOH @ 1mA LOAD
60
50
VOL @ 1mA LOAD
40
40
20
30
0
20
–20
10
0
–40 –25
–10
5
35
20
50
65
TEMPERATURE (°C)
80
95
110
04356-0-031
CMRR (dB)
60
04356-0-028
–40
–60
100
125
1k
10k
FREQUENCY (Hz)
100k
Figure 34. Common-Mode Rejection Ratio vs. Frequency
Figure 31. Output Voltage Swing vs. Temperature
1.8
60
VS = 1.8V
TA = 25°C
AV = 1
OUTPUT SWING (VP-P)
1.5
40
30
OS–
20
VS= 1.8V
VIN= 1.7V p–p
T= 25°C
AV= 1
1.2
0.9
0.6
OS+
0
10
0.3
04356-0-029
10
100
LOAD CAPACITANCE (pF)
0.0
0.01
1000
04356-0-032
OUTPUT SWING (mV)
100
FREQUENCY (Hz)
140
90
SMALL SIGNAL OVERSHOOT (%)
10
Figure 33. Open-Loop Gain and Phase vs. Frequency
100
50
135
40
–100
10
1
180
0.1
1
FREQUENCY (kHz)
10
100
Figure 35. Closed-Loop Output Voltage Swing vs. Frequency
Figure 32. Small Signal Overshoot vs. Load Capacitance
Rev. A | Page 10 of 16
PHASE (Degree)
100
225
VS = ±0.9V
RL = 100kΩ
CL = 20pF
φ = 70°
80
04356-0-030
100
VS = 1.8V
TA = 25°C
04356-0-027
OUTPUT VOLTAGE TO SUPPLY RAIL (mV)
1000
AD8603/AD8607/AD8609
176
VS = ±0.9V
154
132
110
88
66
44
04356-0-048
04356-0-033
VOLTAGE (50mV/DIV)
VOLTAGE NOISE DENSITY (nV/ Hz)
VS = 1.8V
RL = 10kΩ
CL = 200pF
AV = 1
22
0
0
1
2
3
4
5
6
7
FREQUENCY (kHz)
8
9
10
TIME (4µs/DIV)
Figure 39. Voltage Noise Density
Figure 36. Small Signal Transient
0
VS = 1.8V
RL = 10kΩ
CL = 200pF
AV = 1
–100
1k
10k
FREQUENCY (Hz)
100k
Figure 40. Channel Separation
168
VS = ±0.9V
140
112
84
56
04356-0-047
VOLTAGE NOISE DENSITY (nV/ Hz)
–80
04356-A-043
CHANNEL SEPARATION (dB)
04356-0-034
VOLTAGE (500mV/DIV)
–60
–140
100
Figure 37. Large Signal Transient
28
–40
–120
TIME (20µs/DIV)
0
0
VS = ±2.5V, ±0.9V
–20
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
FREQUENCY (kHz)
Figure 38. Voltage Noise Density
Rev. A | Page 11 of 16
1M
AD8603/AD8607/AD8609
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.
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.
VS = ±0.9V
VIN = 100mV
CL = 2nF
RL = 10kΩ
VS = ±2.5V
VIN = 6V p-p
AV = 1
RL = 10kΩ
VOLTAGE (1V/DIV)
VIN
04356-0-037
04356-0-038
VOUT
Figure 42. Output Response to a 2 nF Capacitive Load, without Snubber
VEE
Figure 41. No Phase Response
V–
V+
INPUT OVERVOLTAGE PROTECTION
200mV +
–
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.
RS
150Ω
VCC C
S
47pF
CL
04356-A-039
TIME (4µs/DIV)
Figure 43. Snubber Network
VSY = ±0.9V
VIN = 100mV
CL = 2nF
RL = 10kΩ
RS = 150Ω
CS = 470pF
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 equation
(VIN – VS)/(RS + 200 Ω) ≤ 5 mA
DRIVING CAPACITIVE LOADS
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.
04356-0-040
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.
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)
100~500
1500
1600~2000
Rev. A | Page 12 of 16
RS (Ω)
500
100
400
CS (pF)
680
330
100
AD8603/AD8607/AD8609
R2
R1
PROXIMITY SENSORS
VEE 99kΩ
1kΩ
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.
VCC
V–
U5
AD8603
AD8541
V+
V+
VIN
04356-A-041
V–
VCC
R3
1kΩ
VEE
R4
99kΩ
Figure 45. High Gain Composite Amplifier
R2
100kΩ
COMPOSITE AMPLIFIERS
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
bandwidth is increased substantially, and the input offset
voltage and noise of the AD8541 become insignificant since
they are divided by the high gain of the AD8603.
The circuit of Figure 46 offers a high bandwidth (nearly double
that of the AD8603), a high output current, and a very low
power consumption of less than 100 µA.
Rev. A | Page 13 of 16
VEE
AD8603
VCC
R1
1kΩ
VIN
V–
V+
R3
1kΩ
V+
R4
V–
VCC
C2
100Ω
AD8541
VEE
C3
Figure 46. Low Power Composite Amplifier
04356-A-042
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 (Figure 45) improves the
phase margin. Picking CF = 50 pF yields a phase margin of
about 45° for the values shown in Figure 45.
AD8603/AD8607/AD8609
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.
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
VCC
PHOTODIODES
Rev. A | Page 14 of 16
VEE
Figure 47. Photodiode Circuit
04356-0-044
AD8603
C1
10pF
Figure 47 shows a simple photodiode circuit. The feedback
capacitor helps the circuit maintain stability. The signal
bandwidth can be increased at the expense of an increase in the
total noise; a low-pass filter can be implemented by a simple RC
R1
1000MΩ
Photodiodes have a wide range of applications from bar code
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.
AD8603/AD8607/AD8609
OUTLINE DIMENSIONS
5.00 (0.1968)
4.80 (0.1890)
8
5
4.00 (0.1574)
3.80 (0.1497) 1
6.20 (0.2440)
5.80 (0.2284)
4
1.27 (0.0500)
BSC
0.50 (0.0196)
× 45°
0.25 (0.0099)
1.75 (0.0688)
1.35 (0.0532)
0.25 (0.0098)
0.10 (0.0040)
0.51 (0.0201)
COPLANARITY
SEATING 0.31 (0.0122)
0.10
PLANE
8°
0.25 (0.0098) 0° 1.27 (0.0500)
0.40 (0.0157)
0.17 (0.0067)
COMPLIANT TO JEDEC STANDARDS MS-012AA
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
Figure 48. 8-Lead Standard Small Outline Package (SOIC) [R-8]
Dimensions shown in millimeters and (inches)
2.90 BSC
5
4
2.80 BSC
1.60 BSC
1
2
3
PIN 1
0.95 BSC
1.90
BSC
0.90
0.87
0.84
1.00 MAX
0.10 MAX
0.50
0.30
SEATING
PLANE
0.20
0.08
8°
4°
0.60
0.45
0.30
COMPLIANT TO JEDEC STANDARDS MO-193AB
Figure 49. 5-Lead Thin Small Outline Transistor Package [TSOT]
(UJ-5)
Dimensions in millimeters
3.00
BSC
8
5
4.90
BSC
3.00
BSC
4
PIN 1
0.65 BSC
1.10 MAX
0.15
0.00
0.38
0.22
COPLANARITY
0.10
0.23
0.08
8°
0°
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MO-187AA
Figure 50. 8-Lead MSOP Package (RM-8)
Dimensions in millimeters
Rev. A | Page 15 of 16
0.80
0.60
0.40
AD8603/AD8607/AD8609
8.75 (0.3445)
8.55 (0.3366)
4.00 (0.1575)
3.80 (0.1496)
14
8
1
7
6.20 (0.2441)
5.80 (0.2283)
1.27 (0.0500)
BSC
0.25 (0.0098)
0.10 (0.0039)
0.51 (0.0201)
0.31 (0.0122)
COPLANARITY
0.10
0.50 (0.0197)
× 45°
0.25 (0.0098)
1.75 (0.0689)
1.35 (0.0531)
SEATING
PLANE
8°
0.25 (0.0098) 0° 1.27 (0.0500)
0.40 (0.0157)
0.17 (0.0067)
COMPLIANT TO JEDEC STANDARDS MS-012AB
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
Figure 51. 14-Lead Standard Small Outline Package (SOIC) [R-14]
Dimensions shown in millimeters and (inches)
5.10
5.00
4.90
14
8
4.50
4.40
4.30
6.40
BSC
1
7
PIN 1
1.05
1.00
0.80
0.65
BSC
1.20
MAX
0.15
0.05
0.30
0.19
0.20
0.09
SEATING
COPLANARITY
PLANE
0.10
0.75
0.60
0.45
8°
0°
COMPLIANT TO JEDEC STANDARDS MO-153AB-1
Figure 52. 14-Lead Thin Shrink Small Outline Package (TSSOP) [RU-14]
Dimensions shown in millimeters
ORDERING GUIDE
Model
AD8603AUJ-R2
AD8603AUJ-REEL
AD8603AUJ-REEL7
AD8607ARM-R2
AD8607ARM-REEL
AD8607AR
AD8607AR-REEL
AD8607AR-REEL7
AD8609AR
AD8609AR-REEL
AD8609AR-REEL7
AD8609ARU
AR8609ARU-REEL
Temperature Range
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
Package Description
5-Lead TSOT-23
5-Lead TSOT-23
5-Lead TSOT-23
8-Lead MSOP
8-Lead MSOP
8-Lead SOIC
8-Lead SOIC
8-Lead SOIC
14-Lead SOIC
14-Lead SOIC
14-Lead SOIC
14-Lead TSSOP
14-Lead TSSOP
© 2003 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
C04356–0–10/03(A)
Rev. A | Page 16 of 16
Package Option
UJ-5
UJ-5
UJ-5
RM-8
RM-8
R-8
R-8
R-8
R-14
R-14
R-14
RU-14
RU-14
Branding
BFA
BFA
BFA
A00
A00