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FEATURES Single Supply Operation: +2.7 V to +5.5 V Low Supply Current: 45 A/Amplifier Wide Bandwidth: 1 MHz No Phase Reversal Low Input Currents: 4 pA Unity Gain Stable Rail-to-Rail Input and Output APPLICATIONS ASIC Input or Output Amplifier Sensor Interface Piezo Electric Transducer Amplifier Medical Instrumentation Mobile Communication Audio Output Portable Systems GENERAL DESCRIPTION
NC 1 IN A 2 +IN A 3 V 4
General Purpose CMOS Rail-to-Rail Amplifiers AD8541/AD8542/AD8544
PIN CONFIGURATIONS SO-8 (R)
AD8541
8 NC 7 V+ 6 OUT A 5 NC
SOT-23-5 (RT)
AD8541
OUT A 1 V 2 4 IN A 5 V+
+IN A 3
NC = NO CONNECT
SO-8 (R), RM-8, and RU-8
OUT A 1 IN A 2 +IN A 3 V 4 8 V+
SO-14 (R) and RU-14
OUT A 1 IN A 2 +IN A 3 V+ 4 +IN B 5 IN B 6 OUT B 7 14 OUT D 13 IN D 12 +IN D 11 V 10 +IN C 9 IN C 8 OUT C
AD8542
7 OUT B 6 IN B 5 +IN B
AD8544
The AD8541/AD8542/AD8544 are single, dual and quad railto-rail input and output single supply amplifiers featuring very low supply current and 1 MHz bandwidth. All are guaranteed to operate from a +2.7 V single supply as well as a +5 V supply. These parts provide 1 MHz bandwidth at low current consumption of 45 A per amplifier. Very low input bias currents enable the AD8541/AD8542/AD8544 to be used for integrators, photodiode amplifiers, piezo electric sensors and other applications with high source impedance. Supply current is only 45 A per amplifier, ideal for battery operation. Rail-to-rail inputs and outputs are useful to designers buffering ASICs in single supply systems. The AD8541/AD8542/AD8544 are optimized to maintain high gains at lower supply voltages, making them useful for active filters and gain stages. The AD8541/AD8542/AD8544 are specified over the extended industrial (-40C to +125C) temperature range. The AD8541 is available in 8-lead SO and 5-lead SOT-23 packages. The AD8542 is available in 8-lead SO, 8-lead MSOP, and 8-lead TSSOP surface mount packages. The AD8544 is available in 14-lead narrow SO-14 and 14-lead TSSOP surface mount packages. All TSSOP, MSOP, and SOT versions are available in tape and reel only.
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 which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 (c) Analog Devices, Inc., 2000
AD8541/AD8542/AD8544-SPECIFICATIONS
ELECTRICAL CHARACTERISTICS (V = +2.7 V, V
S CM
= +1.35 V, TA = +25 C unless otherwise noted)
Min Typ 1 Max 6 7 60 100 1,000 30 50 500 +2.7 Units mV mV pA pA pA pA pA pA V dB dB V/mV V/mV V/mV V/C fA/C fA/C fA/C V V mV mV mA mA dB dB A A V/s s kHz Degrees nV/Hz nV/Hz pA/Hz
Parameter INPUT CHARACTERISTICS Offset Voltage Input Bias Current
Symbol VOS IB IOS
Conditions
-40C TA +125C 4 -40C TA +85C -40C TA +125C 0.1 -40C TA +85C -40C TA +125C VCM = 0 V to +2.7 V -40C TA +125C RL = 100 k , VO = +0.5 V to +2.2 V -40C TA +85C -40C TA +125C -40C TA +125C -40C TA +85C -40C TA +125C -40C TA +125C IL = 1 mA -40C TA +125C IL = 1 mA -40C TA +125C VOUT = VS - 1 V f = 200 kHz, AV = 1 VS = +2.5 V to +6 V -40C TA +125C VO = 0 V -40C TA +125C RL = 100 k To 0.1% (1 V Step) 0 40 38 100 50 2 45 500
Input Offset Current
Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain
CMRR AVO VOS /T IB /T IOS /T VOH VOL IOUT ISC ZOUT PSRR ISY
Offset Voltage Drift Bias Current Drift Offset Current Drift 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 Gain Bandwidth Product Phase Margin NOISE PERFORMANCE Voltage Noise Density Current Noise Density
Specifications subject to change without notice.
4 100 2,000 25 +2.575 +2.65 +2.550 35 100 125 15 20 50 65 60 76 38 55 75
SR tS GBP o en en in
0.4
0.75 5 980 63 40 38 <0.1
f = 1 kHz f = 10 kHz
-2-
REV. A
AD8541/AD8542/AD8544 ELECTRICAL CHARACTERISTICS (V = +3.0 V, V
S CM
= +1.5 V, TA = +25 C unless otherwise noted)
Min Typ 1 Max 6 7 60 100 1,000 30 50 500 +3 Units mV mV pA pA pA pA pA pA V dB dB V/mV V/mV V/mV V/C fA/C fA/C fA/C V V mV mV mA mA dB dB A A V/s s kHz Degrees nV/Hz nV/Hz pA/Hz
Parameter INPUT CHARACTERISTICS Offset Voltage Input Bias Current
Symbol VOS IB IOS
Conditions
-40C TA +125C 4 -40C TA +85C -40C TA +125C 0.1 -40C TA +85C -40C TA +125C VCM = 0 V to +3 V -40C TA +125C RL = 100 k , VO = +0.5 V to +2.2 V -40C TA +85C -40C TA +125C -40C TA +125C -40C TA +85C -40C TA +125C -40C TA +125C IL = 1 mA -40C TA +125C IL = 1 mA -40C TA +125C VOUT = VS - 1 V f = 200 kHz, AV = 1 VS = +2.5 V to +6 V -40C TA +125C VO = 0 V -40C TA +125C RL = 100 k To 0.01% (1 V Step) 0 40 38 100 50 2 45 500
Input Offset Current
Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain
CMRR AVO VOS /T IB /T IOS /T VOH VOL IOUT ISC ZOUT PSRR ISY
Offset Voltage Drift Bias Current Drift Offset Current Drift 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 Gain Bandwidth Product Phase Margin NOISE PERFORMANCE Voltage Noise Density Current Noise Density
Specifications subject to change without notice.
4 100 2,000 25 +2.875 +2.955 +2.850 32 100 125 18 25 50 65 60 76 40 60 75
SR tS GBP o en en in
0.4
0.8 5 980 64 42 38 <0.1
f = 1 kHz f = 10 kHz
REV. A
-3-
AD8541/AD8542/AD8544-SPECIFICATIONS
ELECTRICAL CHARACTERISTICS (V = +5.0 V, V
S CM
= +2.5 V, TA = +25 C unless otherwise noted)
Min Typ 1 Max 6 7 60 100 1,000 30 50 500 +5 Units mV mV pA pA pA pA pA pA V dB dB V/mV V/mV V/mV V/C fA/C fA/C fA/C V V mV mV mA mA dB dB A A V/s kHz s kHz Degrees nV/Hz nV/Hz pA/Hz
Parameter INPUT CHARACTERISTICS Offset Voltage Input Bias Current
Symbol VOS IB IOS
Conditions
-40C TA +125C 4 -40C TA +85C -40C TA +125C 0.1 -40C TA +85C -40C TA +125C VCM = 0 V to +5 V -40C TA +125C RL = 100 k , VO = +0.5 V to +2.2 V -40C TA +85C -40C TA +125C -40C TA +125C -40C TA +85C -40C TA +125C -40C TA +125C IL = 1 mA -40C TA +125C IL = 1 mA -40C TA +125C VOUT = VS - 1 V f = 200 kHz, AV = 1 VS = +2.5 V to +6 V -40C TA +125C VO = 0 V -40C TA +125C RL = 100 k, CL = 200 pF 1% Distortion To 0.1% (1 V Step) 0 40 38 20 10 2 48 40
Input Offset Current
Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain
CMRR AVO VOS /T IB /T IOS /T VOH VOL IOUT ISC ZOUT PSRR ISY
Offset Voltage Drift Bias Current Drift Offset Current Drift 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 Full-Power Bandwidth Settling Time Gain Bandwidth Product Phase Margin NOISE PERFORMANCE Voltage Noise Density Current Noise Density
Specifications subject to change without notice.
4 100 2,000 25 +4.9 +4.965 +4.875 25 100 125 30 60 45 65 60 76 45 65 85
SR BWP tS GBP o en en in
0.45
0.92 70 6 1,000 67 42 38 <0.1
f = 1 kHz f = 10 kHz
-4-
REV. A
AD8541/AD8542/AD8544
ABSOLUTE MAXIMUM RATINGS
1
PACKAGE INFORMATION
Supply Voltage(VS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . +6 V Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND to VS Differential Input Voltage2 . . . . . . . . . . . . . . . . . . . . . . . 6 V Storage Temperature Range . . . . . . . . . . . . -65C to +150C Operating Temperature Range . . . . . . . . . . -40C to +125C Junction Temperature Range . . . . . . . . . . . . -65C to +150C Lead Temperature Range (Soldering, 60 sec) . . . . . . . +300C
NOTES 1 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 For supplies less than +6 V, the differential input voltage is equal to VS.
Package Type 5-Lead SOT-23 (RT) 8-Lead SOIC (R) 8-Lead MSOP (RM) 8-Lead TSSOP (RU) 14-Lead SOIC (R) 14-Lead TSSOP (RU)
JA
1
JC
Units C/W C/W C/W C/W C/W C/W
256 158 210 240 120 240
81 43 45 43 36 43
NOTE 1 JA is specified for worst case conditions, i.e., JA is specified for device soldered onto a circuit board for surface mount packages.
ORDERING GUIDE
Model AD8541AR AD8541ART* AD8542AR AD8542ARM* AD8542ARU* AD8544AR AD8544ARU*
Temperature Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C
Package Description 8-Lead SOIC 5-Lead SOT-23 8-Lead SOIC 8-Lead MSOP 8-Lead TSSOP 14-Lead SOIC 14-Lead TSSOP
Package Option SO-8 RT-5 SO-8 RM-8 RU-8 SO-14 RU-14
Branding Information A4A AVA
*Available in reels only.
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 AD8541/AD8542/AD8544 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.
WARNING!
ESD SENSITIVE DEVICE
REV. A
-5-
AD8541/AD8542/AD8544 -Typical Performance Characteristics
180 160 VS = +5V VCM = +2.5V TA = +25 C
1.0 0.5
INPUT OFFSET VOLTAGE - mV
9
VS = +2.7V AND +5V VCM = VS /2
INPUT BIAS CURRENT - pA
8 7 6 5 4 3 2 1
NUMBER OF AMPLIFIERS
140 120 100 80 60 40 20 0 4.5
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 55 35 15 5 25 45 65 85 105 125 145 TEMPERATURE - C
VS = +2.7V AND +5V VCM = VS /2
3.5 2.5 1.5 0.5 0.5 1.5 2.5 3.5 4.5 INPUT OFFSET VOLTAGE - mV
0 0.5
0.5 1.5 2.5 3.5 4.5 COMMON-MODE VOLTAGE - V
5.5
Figure 1. Input Offset Voltage Distribution
Figure 2. Input Offset Voltage vs. Temperature
Figure 3. Input Bias Current vs. Common-Mode Voltage
400
7
160
POWER SUPPLY REJECTION - dB
INPUT OFFSET CURRENT - pA
350
INPUT BIAS CURRENT - pA
VS = +2.7V AND +5V VCM = VS /2
6 5 4 3 2 1 0
VS = +2.7V AND +5V VCM = VS /2
140 120 100 80 60 40 20 0 20
VS = +2.7V TA = +25 C
300 250 200 150 100 50 0
PSRR +PSRR
40
20
0
20 40 60 80 100 120 140 TEMPERATURE - C
1
55
35
15 5 25 45 65 85 105 125 145 TEMPERATURE - C
40 100
1k
10k 100k FREQUENCY - Hz
1M
10M
Figure 4. Input Bias Current vs. Temperature
Figure 5. Input Offset Current vs. Temperature
Figure 6. Power Supply Rejection Ratio vs. Frequency
10k VS = +2.7V TA = +25 C
3.0
SMALL SIGNAL OVERSHOOT - %
60
OUTPUT VOLTAGE - mV
1k 100
2.5
OUTPUT SWING - Vp-p
VS = +2.7V VIN = 2.5Vp-p RL = 2k TA = +25 C
50
VS = +2.7V RL = TA = +25 C
2.0
40 +OS 30 OS
SOURCE 10 SINK 1
1.5
1.0
20
0.1 0.01 0.001
0.5
10 0 10
0.01
0.1 1 10 LOAD CURRENT - mA
100
0 1k
10k
100k 1M FREQUENCY - Hz
10M
1k 100 CAPACITANCE - pF
10k
Figure 7. Output Voltage to Supply Rail vs. Load Current
Figure 8. Closed-Loop Output Voltage Swing vs. Frequency
Figure 9. Small Signal Overshoot vs. Load Capacitance
-6-
REV. A
AD8541/AD8542/AD8544
60 60
SMALL SIGNAL OVERSHOOT - %
50
SMALL SIGNAL OVERSHOOT - %
VS = +2.7V RL = 10k TA = +25 C
50
VS = +2.7V RL = 2k TA = +25 C
40 +OS 30 OS
40 +OS OS 20
VS = +2.7V RL = 100k CL = 300pF AV = +1 TA = +25 C
30
1.35V
20
10 0 10
10 0 10
50mV 10 s
1k 100 CAPACITANCE - pF
10k
1k 100 CAPACITANCE - pF
10k
Figure 10. Small Signal Overshoot vs. Load Capacitance
Figure 11. Small Signal Overshoot vs. Load Capacitance
Figure 12. Small Signal Transient Response
VS = +2.7V RL = NO LOAD TA = +25 C 80
GAIN - dB
POWER SUPPLY REJECTION RATIO - dB
160 140 120 100 80 60 +PSRR 40 20 0 20 40 100 1k 10k 100k FREQUENCY - Hz 1M 10M PSRR VS = +5V TA = +25 C
45 90 135 180
60 40 20 0
1.35V VS = +2.7V RL = 2k AV = +1 TA = +25 C 500mV 10 s
1k
10k
100k 1M FREQUENCY - Hz
10M
Figure 13. Large Signal Transient Response
Figure 14. Open-Loop Gain and Phase vs. Frequency
PHASE SHIFT - Degrees
Figure 15. Power Supply Rejection Ratio vs. Frequency
90
10k
5.0 VS = +5V TA = +25 C 4.5 4.0 VS = +5V VIN = +4.9Vp-p RL = NO LOAD TA = +25 C
COMMON-MODE REJECTION - dB
80 70 60 50 40 30 20 10 0 10 1k
VS = +5V TA = +25 C
1k
OUTPUT VOLTAGE - mV
OUTPUT SWING - Vp-p
100 SOURCE 10 SINK 1
3.5 3.0 2.5 2.0 1.5 1.0 0.5
0.1 0.01 0.001
10k
100k 1M FREQUENCY - Hz
10M
0.01
0.1 1 10 LOAD CURRENT - mA
100
0 1k
10k
100k 1M FREQUENCY - Hz
10M
Figure 16. Common-Mode Rejection Ratio vs. Frequency
Figure 17. Output Voltage to Supply Rail vs. Frequency
Figure 18. Closed Loop Output Voltage Swing vs. Frequency
REV. A
-7-
AD8541/AD8542/AD8544
5.0
SMALL SIGNAL OVERSHOOT - %
60 60
4.0
OUTPUT SWING - Vp-p
50
SMALL SIGNAL OVERSHOOT - %
4.5
3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 1k 10k
VS = +5V VIN = +4.9Vp-p RL = 2k TA = +25 C
VS = +5V RL = 10k TA = +25 C
50
VS = +5V RL = 2k TA = +25 C
40 +OS 30 OS
40 +OS OS 20
30
20
10 0 10
10 0 10
100k 1M FREQUENCY - Hz
10M
1k 100 CAPACITANCE - pF
10k
1k 100 CAPACITANCE - pF
10k
Figure 19. Closed-Loop Output Voltage Swing vs. Frequency
Figure 20. Small Signal Overshoot vs. Load Capacitance
Figure 21. Small Signal Overshoot vs. Load Capacitance
60
SMALL SIGNAL OVERSHOOT - %
50
VS = +5V RL = TA = +25 C
40 +OS 30 OS 20
VS = +5V RL = 100k CL = 300pF AV = +1 TA = +25 C
2.5V
2.5V VS = +5V RL = 2k AV = +1 TA = +25 C 50mV 10 s 1V 10 s
10 0 10
100 1k CAPACITANCE - pF
10k
Figure 22. Small Signal Overshoot vs. Load Capacitance
Figure 23. Small Signal Transient Response
Figure 24. Large Signal Transient Response
VIN
45 90 135 180
PHASE SHIFT - Degrees
SUPPLY CURRENT/AMPLIFIER - A
VS = +5V RL = NO LOAD TA = +25 C 80
GAIN - dB
VS = +5V RL = 10k AV = +1 TA = +25 C
60 TA = +25 C 50
40
60 40 20 0
VOUT 2.5V
30
20
10
1V
1k 10k 100k 1M FREQUENCY - Hz 10M
20 s
0
0
1
2 3 4 SUPPLY VOLTAGE - V
5
6
Figure 25. Open-Loop Gain & Phase vs. Frequency
Figure 26. No Phase Reversal
Figure 27. Supply Current per Amplifier vs. Supply Voltage
-8-
REV. A
AD8541/AD8542/AD8544
55
SUPPLY CURRENT/AMPLIFIER - A
1,000 VS = +2.7V AND +5V AV = +1 800 TA = +25 C 900
VS = +5V
50 45 40 VS = +2.7V 35 30 25
IMPEDANCE -
700 600 500 400 300 200 100
VS = +5V AV = +1 MARKER SET @ 10kHz MARKER READING: 37.6 V/ Hz TA = +25 C
20 55 35 15 5 25 45 65 85 105 125 145 TEMPERATURE - C
0 1k
200mV/DIVISION
0
10k
100k 1M FREQUENCY - Hz
10M
100M
5
10 15 FREQUENCY - kHz
20
25
Figure 28. Supply Current per Amplifier vs. Temperature
Figure 29. Closed-Loop Output Impedance vs. Frequency
Figure 30. Voltage Noise
NOTES ON THE AD854x AMPLIFIERS
The AD8541/AD8542/AD8544 amplifiers are improved performance general purpose operational amplifiers. Performance has been improved over previous amplifiers in several ways.
Lower Supply Current for 1 MHz Gain Bandwidth
The AD854x series typically uses 45 microamps of current per amplifier. This is much less than the 200 A to 700 A used in earlier generation parts with similar performance. This makes the AD854x series a good choice for upgrading portable designs for longer battery life. Alternatively, additional functions and performance can be added at the same current drain.
Higher Output Current
the circuit to no longer attenuate at the ideal notch frequency. To achieve desired performance, 1% or better component tolerances or special component screens are usually required. One method to desensitize the circuit-to-component mismatch is to increase R2 with respect to R1, which lowers Q. A lower Q increases attenuation over a wider frequency range, but reduces attenuation at the peak notch frequency.
5.0V R 100k C2 53.6 F R/2 50k 2.5VREF C 26.7nF C 26.7nF R2 2.5k 5 6 R1 97.5k 1 R1 R1+R2 R 100k 3 2 8 U1 4
1/2 AD8542
1
V OUT
At +5 V single supply, the short circuit current is typically 60 A. Even 1 V from the supply rail, the AD854x amplifiers can provide 30 mA, sourcing or sinking. Sourcing and sinking is strong at lower voltages, with 15 mA available at +2.7 V, and 18 mA at 3.0 V. For even higher output currents, please see the Analog Devices AD8531/AD853/AD8534 parts, with output currents to 250 mA. Information on these parts is available from your Analog Devices representative, and datasheets are available at the Analog Devices website at www.analog.com.
Better Performance at Lower Voltages
1/2 AD8542
7 U2
f0 = f0 =
1 2RC
41
[
]
5.0V R 3 2 7
2.5VREF
Figure 31. 60 Hz Twin-T Notch Filter, Q = 10
The AD854x family parts have been designed to provide better ac performance, at 3.0 V and 2.7 V, than previously available parts. Typical gain-bandwidth product is close to 1 MHz at 2.7 V. Voltage gain at 2.7 V and 3.0 V is typically 500,000. Phase margin is typically over +60C, making the part easy to use.
APPLICATIONS Notch Filter
R
AD8541
4 6
V OUT
VIN
2C
The AD8542 has very high open loop gain (especially with supply voltage below 4 V), which makes it useful for active filters of all types. For example, Figure 31 illustrates the AD8542 in the classic Twin-T Notch Filter design. The Twin-T Notch is desired for simplicity, low output impedance and minimal use of op amps. In fact, this notch filter may be designed with only one op amp if Q adjustment is not required. Simply remove U2 as illustrated in Figure 32. However, a major drawback to this circuit topology is ensuring that all the Rs and Cs closely match. The components must closely match or notch frequency offset and drift will cause REV. A -9-
2.5VREF C
R/2
C
Figure 32. 60 Hz Twin-T Notch Filter, Q =
(Ideal)
Figure 33 diagrams another example of the AD8542 in a notch filter circuit. The FNDR notch filter has several unique features as compared to the Twin-T Notch including: less critical matching requirements; Q is directly proportional to a single resistor R1. While matching component values is still important, it is also much easier and/or less expensive to
AD8541/AD8542/AD8544
accomplish in the FNDR circuit. For example, the Twin-T Notch uses three capacitors with two unique values, whereas the FNDR circuit uses only two capacitors, which may be of the same value. U3 is simply a buffer that is added to lower the output impedance of the circuit.
R1 Q ADJUST 200 C1 1F R 2.61k C2 1F R 2.61k R 2.61k 1 2 LC1 R 2.61k 2.5VREF 13 12 3 2 4 U1 11 9 10
Photodiode Application
1/4 AD8544
U3 8
The AD854x family has very high impedance with input bias current typically around 4 pA. This characteristic allows the AD854x op amps to be used in photodiode applications and other applications that require high input impedance. Note that the AD854x has significant voltage offset, which can be removed by capacitive coupling or software calibration. Figure 35, illustrates a photodiode or current measurement application. The feedback resistor is limited to 10 M to avoid excessive output offset. Also note that a resistor is not needed on the noninverting input to cancel bias current offset, because the bias current related output offset is not significant when compared to the voltage offset contribution. For the best performance follow the standard high impedance layout techniques including: shield circuit, clean circuit board, put a trace connected to the noninverting input around the inverting input, and use separate analog and digital power supplies.
C 100pF
V OUT
2.5VREF
1/4 AD8544
1
1/4 AD8544
7 U2
6 5
1/4 AD8544
U4 14 NC SPARE V+ R 10M
f=
L = R2C2
2.5VREF
OR
2 3 D
7 6 V OUT
Figure 33. FNDR 60 Hz Notch Filter with Output Buffer
Comparator Function
4
AD8541
A comparator function is a common application for a spare op amp in a quad package. Figure 34 illustrates 1/4 of the AD8544 as a comparator in a standard overload detection application. Unlike so many op amps, the AD854x family can double as comparator because this op amp family has rail-to-rail differential input range, rail-to-rail output, and a great speed vs. power ratio. R2 is used to introduce hysteresis. The AD854x when used as comparators have 5 s propagation delay @ 5 V and 5 s overload recovery time.
R2 1M R1 1k
2.5VREF
2.5VREF
Figure 35. High Input Impedance Application-Photodiode Amplifier
V OUT
VIN 2.5VDC 2.5VREF
1/4 AD8544
Figure 34. The AD854x Comparator Application-Overload Detector
-10-
REV. A
AD8541/AD8542/AD8544
* AD8542 SPICE Macro-model Typical Values * 6/98, Ver. 1 * TAM / ADSC * * Copyright 1998 by Analog Devices * * Refer to "README.DOC" file for License Statement. Use of this * model indicates your acceptance of the terms and provisions in * the License Statement. * * Node Assignments * noninverting input * | inverting input * || positive supply * || | negative supply * || | | output * || ||| * || ||| .SUBCKT AD8542 1 2 99 50 45 * * INPUT STAGE * M1 4 1 8 8 PIX L=0.6E-6 W=16E-6 M2 6 7 8 8 PIX L=0.6E-6 W=16E-6 M3 11 1 10 10 NIX L=0.6E-6 W=16E-6 M4 12 7 10 10 NIX L=0.6E-6 W=16E-6 RC1 4 50 20E3 RC2 6 50 20E3 RC3 99 11 20E3 RC4 99 12 20E3 C1 4 6 1.5E-12 C2 11 12 1.5E-12 I1 99 8 1E-5 I2 10 50 1E-5 V1 99 9 0.2 V2 13 50 0.2 D1 8 9 DX D2 13 10 DX EOS 7 2 POLY(3) (22,98) (73,98) (81,0) 1E-3 1 1 1 IOS 1 2 2.5E-12 * * CMRR 64dB, ZERO AT 20kHz * ECM1 21 98 POLY(2) (1,98) (2,98) 0 .5 .5 RCM1 21 22 79.6E3 CCM1 21 22 100E-12 RCM2 22 98 50 * * PSRR=90dB, ZERO AT 200Hz * RPS1 70 0 1E6 RPS2 71 0 1E6 CPS1 99 70 1E-5 CPS2 50 71 1E-5 EPSY 98 72 POLY(2) (70,0) (0,71) 0 1 1 RPS3 72 73 1.59E6 CPS3 72 73 500E-12 RPS4 73 98 25 * * VOLTAGE NOISE REFERENCE OF 35nV/rt(Hz) * VN1 80 0 0 RN1 80 0 16.45E-3 HN 81 0 VN1 35 RN2 81 0 1 * * INTERNAL VOLTAGE REFERENCE * VFIX 90 98 DC 1 S1 90 91 (50,99) VSY_SWITCH VSN1 91 92 DC 0 RSY 92 98 1E3 EREF 98 0 POLY(2) (99,0) (50,0) 0 .5 .5 GSY 99 50 POLY(1) (99,50) 0 3.7E-6 * * ADAPTIVE GAIN STAGE * AT Vsy>+4.2, AVol=45 V/mv * AT Vsy<+3.8, AVol=450 V/mv * G1 98 30 POLY(2) (4,6) (11,12) 0 2.5E-5 2.5E-5 VR1 30 31 DC 0 H1 31 98 POLY(2) VR1 VSN1 0 5.45E6 0 0 49.05E9 CF 45 30 10E-12 D3 30 99 DX D4 50 30 DX * * OUTPUT STAGE * M5 45 46 99 99 POX L=0.6E-6 W=375E-6 M6 45 47 50 50 NOX L=0.6E-6 W=500E-6 EG1 99 46 POLY(1) (98,30) 1.05 1 EG2 47 50 POLY(1) (30,98) 1.04 1 * * MODELS * .MODEL POX PMOS (LEVEL=2,KP=20E-6,VTO=+1,LAMBDA=0.067) .MODEL NOX NMOS (LEVEL=2,KP=20E+6,VTO=1,LAMBDA=0.067) .MODEL PIX PMOS (LEVEL=2,KP=20E-6,VTO=+0.7,LAMBDA=0.01,KF=1E-31) .MODEL NIX NMOS (LEVEL=2,KP=20E+6,VTO=0.7,LAMBDA=0.01,KF=1E-31) .MODEL DX D(IS=1E-14) .MODEL VSY_SWITCH VSWITCH(ROFF=100E3,RON=1,VOFF=+4.2,VON=-3.5) .ENDS AD8542
REV. A
-11-
AD8541/AD8542/AD8544
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
8-Lead TSSOP (RU-08)
0.122 (3.10) 0.114 (2.90)
14-Lead TSSOP (RU-14)
0.201 (5.10) 0.193 (4.90)
14 8
8
5
1
4
1
7
PIN 1 0.006 (0.15) 0.002 (0.05) 0.0256 (0.65) BSC 0.0433 (1.10) MAX 0.0079 (0.20) 0.0035 (0.090)
PIN 1 0.006 (0.15) 0.002 (0.05)
8 0 0.028 (0.70) 0.020 (0.50)
0.0433 (1.10) MAX 0.0256 (0.65) BSC 0.0118 (0.30) 0.0075 (0.19) 0.0079 (0.20) 0.0035 (0.090)
0.0118 (0.30) SEATING PLANE 0.0075 (0.19)
SEATING PLANE
8 0
0.028 (0.70) 0.020 (0.50)
8-Lead SOIC (SO-8)
0.1968 (5.00) 0.1890 (4.80)
8 5 4
14-Lead SOIC (SO-14)
0.3444 (8.75) 0.3367 (8.55)
14 1 8 7
0.1574 (4.00) 0.1497 (3.80) 1
0.2440 (6.20) 0.2284 (5.80)
0.1574 (4.00) 0.1497 (3.80)
0.2440 (6.20) 0.2284 (5.80)
PIN 1 0.0098 (0.25) 0.0040 (0.10)
0.0688 (1.75) 0.0532 (1.35)
0.0196 (0.50) x 45 0.0099 (0.25)
PIN 1 0.0098 (0.25) 0.0040 (0.10)
0.0688 (1.75) 0.0532 (1.35)
0.0196 (0.50) x 45 0.0099 (0.25)
0.0500 0.0192 (0.49) SEATING (1.27) PLANE BSC 0.0138 (0.35)
0.0098 (0.25) 0.0075 (0.19)
8 0
0.0500 (1.27) 0.0160 (0.41)
0.0500 SEATING (1.27) PLANE BSC
0.0192 (0.49) 0.0138 (0.35)
0.0099 (0.25) 0.0075 (0.19)
8 0
0.0500 (1.27) 0.0160 (0.41)
5-Lead SOT-23 (RT Suffix)
0.1181 (3.00) 0.1102 (2.80)
8-Lead MSOP (RM-8)
0.122 (3.10) 0.114 (2.90)
0.0669 (1.70) 0.0590 (1.50) PIN 1
5 1 2
4 3
8
5
0.1181 (3.00) 0.1024 (2.60)
0.122 (3.10) 0.114 (2.90)
1 4
0.193 (4.90) BSC
0.0374 (0.95) BSC 0.0748 (1.90) BSC 0.0512 (1.30) 0.0354 (0.90) 0.0059 (0.15) 0.0019 (0.05) 0.0197 (0.50) 0.0138 (0.35) 0.0571 (1.45) 0.0374 (0.95) SEATING PLANE 10 0
PIN 1 0.0256 (0.65) BSC
0.037 (0.95) 0.030 (0.75)
0.0079 (0.20) 0.0031 (0.08)
0.006 (0.15) 0.002 (0.05)
0.043 (1.10) MAX 6 0.016 (0.40) SEATING 0 0.009 (0.23) 0.010 (0.25) PLANE 0.005 (0.13)
0.028 (0.70) 0.016 (0.40)
0.0217 (0.55) 0.0138 (0.35)
-12-
REV. A
PRINTED IN U.S.A.
C3414-0-3/00 (rev. A)
0.177 (4.50) 0.169 (4.30)
0.256 (6.50) 0.246 (6.25)
0.177 (4.50) 0.169 (4.30)
0.256 (6.50) 0.246 (6.25)

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