ANALOG DEVICES AD8546, AD8548 Service Manual
22 μA, RRIO, CMOS, 18 V
Data Sheet
FEATURES
Micropower at high voltage: 22 μA maximum
Low input bias current: 20 pA maximum
Gain bandwidth product: 240 kHz
Slew rate: 80 V/ms
Large signal voltage gain: 110 dB minimum
Single-supply operation: 2.7 V to 18 V
Dual-supply operation: ±1.35 V to ±9 V
Unity-gain stable
APPLICATIONS
Portable medical equipment
Remote sensors
Transimpedance amplifiers
Current monitors
4 mA to 20 mA loop drivers
Buffer/level shifting
GENERAL DESCRIPTION
The AD8546 and AD8548 are dual and quad micropower, high
input impedance amplifiers optimized for low power and wide
operating supply voltage range applications.
The AD8546/AD8548 rail-to-rail input/output (RRIO) feature
provides increased dynamic range to drive low frequency data
converters, making these amplifiers ideal for dc gain and buffering
of sensor front ends or high impedance input sources used in
wireless or remote sensors or transmitters.
The low supply current specification (22 μA) of the AD8546/
AD8548 over a wide operating voltage range of 2.7 V to 18 V
or dual supplies (±1.35 V to ±9 V) makes these amplifiers useful
for a variety of battery-powered, portable applications, such as
ECGs, pulse monitors, glucose meters, smoke and fire detectors,
vibration monitors, and backup battery sensors.
The AD8546/AD8548 are specified over the extended industrial
temperature range of −40°C to +125°C. The AD8546 is available
in an 8-lead MSOP package; the AD8548 is available in a 14-lead
SOIC_N package.
Operational Amplifier
AD8546/AD8548
PIN CONFIGURATIONS
OUT A
1
AD8546
2
–IN A
+IN A
V–
TOP VIEW
3
(Not to Scale)
4
Figure 1. AD8546 (8-Lead MSOP)
OUT A
1
2
–IN A
+IN A
3
AD8548
4
V+
TOP VIEW
(Not to Scale)
+IN B
5
6
–IN B
OUT B
7
Figure 2. AD8548 (14-Lead SOIC_N)
Table 1. Micropower Op Amps
Amplifier
5 V 12 V to 18 V 36 V
Single AD8500 AD8663
AD8505
AD8541
AD8603
ADA4505-1
Dual AD8502 AD8546 OP295
AD8506 AD8657 ADA4062-2
AD8542 AD8667
AD8607 OP281
ADA4505-2
Quad AD8504 AD8548 OP495
AD8508 AD8669 ADA4062-4
AD8544 OP481
AD8609
ADA4505-4
1
See www.analog.com for the latest selection of micropower op amps.
V+
8
7
OUT B
–IN B
6
+IN B
5
OUT D
14
13
–IN D
+IN D
12
11
V–
+IN C
10
9
–IN C
OUT C
8
1
09585-103
Supply Voltage
09585-001
Rev. B
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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
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Tel: 781.329.4700 www.analog.com
Fax: 781.461.3113 ©2011–2012 Analog Devices, Inc. All rights reserved.
AD8546/AD8548 Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Pin Configurations ........................................................................... 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Electrical Characteristics—18 V Operation ............................. 3
Electrical Characteristics—10 V Operation ............................. 4
Electrical Characteristics—2.7 V Operation ............................ 5
Absolute Maximum Ratings ............................................................ 6
Thermal Resistance ...................................................................... 6
ESD Caution .................................................................................. 6
REVISION HISTORY
4/12—Rev. A to Rev. B
Added AD8548 and 14-Lead SOIC .................................. Universal
Changes to Product Title, Features Section, General
Description Section, and Table 1 .................................................... 1
Added Figure 2; Renumbered Figures Sequentially ..................... 1
Moved Electrical Characteristics—18 V Operation Section ...... 3
Changes to Table 2 ............................................................................ 3
Changes to Table 3 ............................................................................ 4
Moved Electrical Characteristics—2.7 V Operation Section ..... 5
Changes to Table 4 ............................................................................ 5
Changes to Table 6 ............................................................................ 6
Changes to Figure 4, Figure 5, Figure 7, and Figure 8 ................. 7
Deleted Figure 8 and Figure 11 ....................................................... 8
Typical Performance Characteristics ..............................................7
Applications Information .............................................................. 17
Input Stage ................................................................................... 17
Output Stage ................................................................................ 18
Rail-to-Rail Input and Output .................................................. 18
Resistive Load ............................................................................. 18
Comparator Operation .............................................................. 19
4 mA to 20 mA Process Control Current Loop Transmitter .. 20
Outline Dimensions ....................................................................... 21
Ordering Guide .......................................................................... 21
Changes to Figure 9, Figure 10, Figure 12, and Figure 13 ............ 8
Changes to Figure 22 and Figure 25 ............................................ 10
Changes to Figure 33 ...................................................................... 12
Changes to Figure 63 and Figure 64 ............................................ 18
Updated Outline Dimensions ....................................................... 21
Added Figure 72 ............................................................................. 21
Changes to Ordering Guide .......................................................... 21
4/11—Rev. 0 to Rev. A
Changes to Product Title, Features Section, Applications
Section, General Description Section, and Table 1 ....................... 1
1/11—Revision 0: Initial Version
Rev. B | Page 2 of 24
Data Sheet AD8546/AD8548
−40°C ≤ TA ≤ +125°C
105
dB
INDM
INCM
OUT
Power Supply Rejection Ratio
PSRR
VSY = 2.7 V to 18 V
95
115 dB
Voltage Noise
en p-p
f = 0.1 Hz to 10 Hz
5
µV p-p
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS—18 V OPERATION
VSY = 18 V, VCM = VSY/2, TA = 25°C, unless otherwise noted.
Table 2.
Parameter Symbol Test Conditions/Comments Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage VOS VCM = 0 V to 18 V 3 mV
VCM = 0.3 V to 17.7 V; −40°C ≤ TA ≤ +125°C 7 mV
VCM = 0 V to 18 V; −40°C ≤ TA ≤ +125°C 12 mV
Offset Voltage Drift ΔVOS/ΔT 3 µV/°C
Input Bias Current IB 5 20 pA
−40°C ≤ TA ≤ +125°C 2.6 nA
Input Offset Current IOS 40 pA
−40°C ≤ TA ≤ +125°C 5.2 nA
Input Voltage Range IVR 0 18 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 18 V 74 95 dB
VCM = 0.3 V to 17.7 V; −40°C ≤ TA ≤ +125°C 68 dB
VCM = 0 V to 18 V; −40°C ≤ TA ≤ +125°C 65 dB
Large Signal Voltage Gain AVO RL = 100 kΩ; VO = 0.5 V to 17.5 V 110 125 dB
Input Resistance RIN 10 GΩ
Input Capacitance
Differential Mode C
Common Mode C
OUTPUT CHARACTERISTICS
Output Voltage High VOH RL = 100 kΩ to VCM; −40°C ≤ TA ≤ +125°C 17.97 V
Output Voltage Low VOL RL = 100 kΩ to VCM; −40°C ≤ TA ≤ +125°C 30 mV
Short-Circuit Current ISC ±12 mA
Closed-Loop Output Impedance Z
POWER SUPPLY
−40°C ≤ TA ≤ +125°C 90 dB
Supply Current per Amplifier ISY IO = 0 mA 18 22 µA
−40°C ≤ TA ≤ +125°C 33 µA
DYNAMIC PERFORMANCE
Slew Rate SR RL = 1 MΩ; CL = 10 pF; AV = +1 80 V/ms
Settling Time to 0.1% tS VIN = 1 V step; RL = 100 kΩ; CL = 10 pF 15 µs
Gain Bandwidth Product GBP RL = 1 MΩ; CL = 10 pF; AV = +1 240 kHz
Phase Margin ΦM RL = 1 MΩ; CL = 10 pF; AV = +1 60 Degrees
Channel Separation CS f = 10 kHz; RL = 1 MΩ 105 dB
NOISE PERFORMANCE
Voltage Noise Density en f = 1 kHz 50 nV/√Hz
f = 10 kHz 45 nV/√Hz
Current Noise Density in f = 1 kHz 0.1 pA/√Hz
3.5 pF
10.5 pF
f = 1 kHz; AV = +1 15 Ω
Rev. B | Page 3 of 24
AD8546/AD8548 Data Sheet
Input Resistance
RIN
10 GΩ
INDM
INCM
OUT
ELECTRICAL CHARACTERISTICS—10 V OPERATION
VSY = 10 V, VCM = VSY/2, TA = 25°C, unless otherwise noted.
Table 3.
Parameter Symbol Test Conditions/Comments Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage VOS VCM = 0 V to 10 V 3 mV
VCM = 0.3 V to 9.7 V; −40°C ≤ TA ≤ +125°C 8 mV
VCM = 0 V to 10 V; −40°C ≤ TA ≤ +125°C 12 mV
Offset Voltage Drift ΔVOS/ΔT 3 µV/°C
Input Bias Current IB 2 15 pA
−40°C ≤ TA ≤ +125°C 2.6 nA
Input Offset Current IOS 30 pA
−40°C ≤ TA ≤ +125°C 5.2 nA
Input Voltage Range IVR 0 10 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 10 V 70 88 dB
VCM = 0.3 V to 9.7 V; −40°C ≤ TA ≤ +125°C 62 dB
VCM = 0 V to 10 V; −40°C ≤ TA ≤ +125°C 60 dB
Large Signal Voltage Gain AVO RL = 100 kΩ; VO = 0.5 V to 9.5 V 105 120 dB
−40°C ≤ TA ≤ +125°C 100 dB
Input Capacitance
Differential Mode C
Common Mode C
OUTPUT CHARACTERISTICS
Output Voltage High VOH RL = 100 kΩ to VCM; −40°C ≤ TA ≤ +125°C 9.98 V
Output Voltage Low VOL RL = 100 kΩ to VCM; −40°C ≤ TA ≤ +125°C 20 mV
Short-Circuit Current ISC ±11 mA
Closed-Loop Output Impedance Z
POWER SUPPLY
Power Supply Rejection Ratio PSRR VSY = 2.7 V to 18 V 95 115 dB
−40°C ≤ TA ≤ +125°C 90 dB
Supply Current per Amplifier ISY IO = 0 mA 18 22 µA
−40°C ≤ TA ≤ +125°C 33 µA
DYNAMIC PERFORMANCE
Slew Rate SR RL = 1 MΩ; CL = 10 pF; AV = +1 75 V/ms
Settling Time to 0.1% tS VIN = 1 V step; RL = 100 kΩ; CL = 10 pF 15 µs
Gain Bandwidth Product GBP RL = 1 MΩ; CL = 10 pF; AV = +1 235 kHz
Phase Margin ΦM RL = 1 MΩ; CL = 10 pF; AV = +1 60 Degrees
Channel Separation CS f = 10 kHz; RL = 1 MΩ 105 dB
NOISE PERFORMANCE
Voltage Noise en p-p f = 0.1 Hz to 10 Hz 5 µV p-p
Voltage Noise Density en f = 1 kHz 50 nV/√Hz
f = 10 kHz 45 nV/√Hz
Current Noise Density in f = 1 kHz 0.1 pA/√Hz
3.5 pF
3.5 pF
f = 1 kHz; AV = +1 15 Ω
Rev. B | Page 4 of 24
Data Sheet AD8546/AD8548
Input Resistance
RIN
10 GΩ
INDM
INCM
OUT
ELECTRICAL CHARACTERISTICS—2.7 V OPERATION
VSY = 2.7 V, VCM = VSY/2, TA = 25°C, unless otherwise noted.
Table 4.
Parameter Symbol Test Conditions/Comments Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage VOS VCM = 0 V to 2.7 V 3 mV
VCM = 0.3 V to 2.4 V; −40°C ≤ TA ≤ +125°C 4 mV
VCM = 0 V to 2.7 V; −40°C ≤ TA ≤ +125°C 12 mV
Offset Voltage Drift ΔVOS/ΔT 3 µV/°C
Input Bias Current IB 1 10 pA
−40°C ≤ TA ≤ +125°C 2.6 nA
Input Offset Current IOS 20 pA
−40°C ≤ TA ≤ +125°C 5.2 nA
Input Voltage Range IVR 0 2.7 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 2.7 V 60 75 dB
VCM = 0.3 V to 2.4 V; −40°C ≤ TA ≤ +125°C 58 dB
VCM = 0 V to 2.7 V; −40°C ≤ TA ≤ +125°C 49 dB
Large Signal Voltage Gain AVO RL = 100 kΩ; VO = 0.5 V to 2.2 V 97 115 dB
−40°C ≤ TA ≤ +125°C 90 dB
Input Capacitance
Differential Mode C
Common Mode C
OUTPUT CHARACTERISTICS
Output Voltage High VOH RL = 100 kΩ to VCM; −40°C ≤ TA ≤ +125°C 2.69 V
Output Voltage Low VOL RL = 100 kΩ to VCM; −40°C ≤ TA ≤ +125°C 10 mV
Short-Circuit Current ISC ±4 mA
Closed-Loop Output Impedance Z
POWER SUPPLY
Power Supply Rejection Ratio PSRR VSY = 2.7 V to 18 V 95 115 dB
−40°C ≤ TA ≤ +125°C 90 dB
Supply Current per Amplifier ISY IO = 0 mA 18 22 µA
−40°C ≤ TA ≤ +125°C 33 µA
DYNAMIC PERFORMANCE
Slew Rate SR RL = 1 MΩ; CL = 10 pF; AV = +1 50 V/ms
Settling Time to 0.1% tS VIN = 1 V step; RL = 100 kΩ; CL = 10 pF 20 µs
Gain Bandwidth Product GBP RL = 1 MΩ; CL = 10 pF; AV = +1 190 kHz
Phase Margin ΦM RL = 1 MΩ; CL = 10 pF; AV = +1 60 Degrees
Channel Separation CS f = 10 kHz; RL = 1 MΩ 105 dB
NOISE PERFORMANCE
Voltage Noise en p-p f = 0.1 Hz to 10 Hz 6 µV p-p
Voltage Noise Density en f = 1 kHz 60 nV/√Hz
f = 10 kHz 56 nV/√Hz
Current Noise Density in f = 1 kHz 0.1 pA/√Hz
3.5 pF
3.5 pF
f = 1 kHz; AV = +1 20 Ω
Rev. B | Page 5 of 24
AD8546/AD8548 Data Sheet
Input Voltage
(V−) − 300 mV to (V+) + 300 mV
Operating Temperature Range
−40°C to +125°C
Package Type
θJA
θJC
Unit
14-Lead SOIC_N (R-14)
115
36
°C/W
ABSOLUTE MAXIMUM RATINGS
Table 5.
Parameter Rating
Supply Voltage 20.5 V
Input Current1 ±10 mA
Differential Input Voltage ±VSY
Output Short-Circuit Duration
to GND
Storage Temperature Range −65°C to +150°C
Junction Temperature Range −65°C to +150°C
Lead Temperature
(Soldering, 60 sec)
1
The input pins have clamp diodes to the power supply pins. Limit the input
current to 10 mA or less whenever input signals exceed the power supply
rail by 0.3 V.
Indefinite
300°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.
THERMAL RESISTANCE
θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages using
a standard 4-layer board.
Table 6. Thermal Resistance
8-Lead MSOP (RM-8) 142 45 °C/W
ESD CAUTION
Rev. B | Page 6 of 24
Data Sheet AD8546/AD8548
0
5
10
15
20
25
30
35
40
–2.0
–1.8
–1.6
–1.4
–1.2
–2.4
–2.2
–1.0
–0.8
–0.6
–0.4
–0.2
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
NUMBER OF AMPLIFIERS
V
OS
(mV)
09585-002
VSY = 2.7V
V
CM
= VSY/2
0
10
20
30
40
50
60
70
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
NUMBER OF AMPLIFIERS
TCVOS (µV/°C)
V
SY
= 2.7V
–40°C ≤ T
A
≤ +125°C
09585-004
–3.0
–2.5
–2.0
–1.5
–1.0
–0.5
0
0.5
1.0
1.5
2.0
2.5
3.0
0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7
V
OS
(mV)
VCM (V)
VSY = 2.7V
09585-005
0
5
10
15
20
25
30
35
40
–2.0
–1.8
–1.6
–1.4
–1.2
–2.4
–2.2
–1.0
–0.8
–0.6
–0.4
–0.2
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
NUMBER OF AMPLIFIERS
V
OS
(mV)
09585-105
V
SY
= 18V
V
CM
= VSY/2
0
10
20
30
40
50
60
70
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
NUMBER OF AMPLIFIERS
TCV
OS
(µV/°C)
VSY = 18V
–40°C ≤ T
A
≤ +125°C
09585-007
–3.0
–2.5
–2.0
–1.5
–1.0
–0.5
0
0.5
1.0
1.5
2.0
2.5
3.0
0 2 4 6 8 10 12 14 16 18
V
OS
(mV)
VCM (V)
VSY = 18V
09585-008
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C, unless otherwise noted.
Figure 3. Input Offset Voltage Distribution
Figure 4. Input Offset Voltage Drift Distribution
Figure 6. Input Offset Voltage Distribution
Figure 7. Input Offset Voltage Drift Distribution
Figure 5. Input Offset Voltage vs. Common-Mode Voltage
Figure 8. Input Offset Voltage vs. Common-Mode Voltage
Rev. B | Page 7 of 24
AD8546/AD8548 Data Sheet
–6
–4
–2
0
2
4
6
0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7
V
OS
(mV)
VCM (V)
VSY = 2.7V
–40°C ≤ T
A
≤ +125°C
09585-110
0.1
1
10
100
1000
10000
25 50 75 100 125
I
B
(pA)
TEMPERATURE (°C)
| IB+ |
| IB– |
VSY = 2.7V
09585-010
–4
–3
–2
–1
0
1
2
3
4
0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7
I
B
(nA)
VCM (V)
25°C
85°C
125°C
VSY = 2.7V
09585-014
–6
–4
–2
0
2
4
6
0 3 6 9 12 15
18
V
OS
(mV)
VCM (V)
V
SY
= 18V
–40°C ≤ T
A
≤ +125°C
09585-113
0.1
1
10
100
1000
10000
25 50 75 100 125
I
B
(pA)
TEMPERATURE (°C)
VSY = 18V
09585-013
| IB+ |
| IB– |
0 2 4 6 8 10 12 14 16 18
V
CM
(V)
25°C
85°C
125°C
VSY = 18V
09585-017
–4
–3
–2
–1
0
1
2
3
4
I
B
(nA)
Figure 9. Input Offset Voltage vs. Common-Mode Voltage
Figure 10. Input Bias Current vs. Temperature
Figure 12. Input Offset Voltage vs. Common-Mode Voltage
Figure 13. Input Bias Current vs. Temperature
Figure 11. Input Bias Current vs. Common-Mode Voltage
Figure 14. Input Bias Current vs. Common-Mode Voltage
Rev. B | Page 8 of 24
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