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| General-Purpose CMOS Rail-to-Rail Amplifiers AD8541/AD8542/AD8544 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 PIN CONFIGURATIONS AD8541 OUT A 1 V- 2 +IN A 3 5 V+ 4 -IN A Figure 1. 5-Lead SC70 and 5-Lead SOT-23 (KS and RJ Suffixes) APPLICATIONS ASIC input or output amplifiers Sensor interfaces Piezoelectric transducer amplifiers Medical instrumentation Mobile communications Audio outputs Portable systems NC 1 -IN A 2 AD8541 8 7 6 5 NC V+ OUT A 00935-002 +IN A 3 V- 4 NC NC = NO CONNECT Figure 2. 8-Lead SOIC (R Suffix) GENERAL DESCRIPTION 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 a 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, piezoelectric sensors, and other applications with high source impedance. The 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 temperature range (-40C to +125C). The AD8541 is available in 5-lead SOT-23, 5-lead SC70, and 8-lead SOIC packages. The AD8542 is available in 8-lead SOIC, 8-lead MSOP, and 8-lead TSSOP surface-mount packages. The AD8544 is available in 14-lead narrow SOIC and 14-lead TSSOP surfacemount packages. All MSOP, SC70, and SOT versions are available in tape and reel only. OUT A -IN A +IN A V- 1 2 3 4 AD8542 8 7 6 5 V+ OUT B -IN B +IN B 00935-003 00935-004 Figure 3. 8-Lead SOIC, 8-Lead MSOP, and 8-Lead TSSOP (R, RM, and RU Suffixes) OUT A -IN A +IN A V+ +IN B -IN B OUT B 1 2 3 4 5 6 7 14 OUT D 13 -IN D 12 +IN D AD8544 11 V- 10 +IN C 9 8 -IN C OUT C Figure 4. 14-Lead SOIC and 14-Lead TSSOP (R and RU Suffixes) Rev. F 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: 781.461.3113 (c)2008 Analog Devices, Inc. All rights reserved. 00935-001 AD8541/AD8542/AD8544 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 1 General Description ......................................................................... 1 Pin Configurations ........................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Electrical Characteristics............................................................. 3 Absolute Maximum Ratings............................................................ 6 Thermal Resistance ...................................................................... 6 ESD Caution.................................................................................. 6 Typical Performance Characteristics ..............................................7 Theory of Operation ...................................................................... 13 Notes on the AD854x Amplifiers............................................. 13 Applications..................................................................................... 14 Notch Filter ................................................................................. 14 Comparator Function ................................................................ 14 Photodiode Application ............................................................ 15 Outline Dimensions ....................................................................... 16 Ordering Guide .......................................................................... 18 REVISION HISTORY 1/08--Rev. E to Rev. F Inserted Figure 21; Renumbered Sequentially.............................. 9 Changes to Figure 22 Caption......................................................... 9 Changes to Notch Filter Section, Figure 35, Figure 36, and Figure 37 .......................................................................................... 13 Updated Outline Dimensions ....................................................... 16 1/07--Rev. D to Rev. E Updated Format..................................................................Universal Changes to Photodiode Application Section .............................. 14 Changes to Ordering Guide .......................................................... 17 8/04--Rev. C to Rev. D Changes to Ordering Guide .............................................................5 Changes to Figure 3........................................................................ 10 Updated Outline Dimensions....................................................... 12 1/03--Rev. B to Rev. C Updated Format..................................................................Universal Changes to General Description .....................................................1 Changes to Ordering Guide .............................................................5 Changes to Outline Dimensions .................................................. 12 Rev. F | Page 2 of 20 AD8541/AD8542/AD8544 SPECIFICATIONS ELECTRICAL CHARACTERISTICS VS = 2.7 V, VCM = 1.35 V, TA = 25C, unless otherwise noted. Table 1. Parameter INPUT CHARACTERISTICS Offset Voltage Input Bias Current Symbol VOS -40C TA +125C IB -40C TA +85C -40C TA +125C Input Offset Current IOS -40C TA +85C -40C TA +125C Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain CMRR AVO 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) 65 60 0 40 38 100 50 2 45 500 0.1 4 Conditions Min Typ 1 Max 6 7 60 100 1000 30 50 500 2.7 Unit 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 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 VOS/T IB/T IOS/T VOH VOL IOUT ISC ZOUT PSRR ISY 4 100 2000 25 2.575 2.550 2.65 35 15 20 50 76 38 55 75 100 125 SR tS GBP M en en in 0.4 0.75 5 980 63 f = 1 kHz f = 10 kHz 40 38 <0.1 nV/Hz nV/Hz pA/Hz Rev. F | Page 3 of 20 AD8541/AD8542/AD8544 VS = 3.0 V, VCM = 1.5 V, TA = 25C, unless otherwise noted. Table 2. Parameter INPUT CHARACTERISTICS Offset Voltage Input Bias Current Symbol VOS -40C TA +125C IB -40C TA +85C -40C TA +125C Input Offset Current IOS -40C TA +85C -40C TA +125C Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain CMRR AVO 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) 65 60 0 40 38 100 50 2 45 500 0.1 4 Conditions Min Typ 1 Max 6 7 60 100 1000 30 50 500 3 Unit 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 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 VOS/T IB/T IOS/T VOH VOL IOUT ISC ZOUT PSRR ISY 4 100 2000 25 2.875 2.850 2.955 32 18 25 50 76 40 60 75 100 125 SR tS GBP M en en in 0.4 0.8 5 980 64 42 38 <0.1 f = 1 kHz f = 10 kHz Rev. F | Page 4 of 20 AD8541/AD8542/AD8544 VS = 5.0 V, VCM = 2.5 V, TA = 25C, unless otherwise noted. Table 3. Parameter INPUT CHARACTERISTICS Offset Voltage Input Bias Current Symbol VOS -40C TA +125C IB -40C TA +85C -40C TA +125C Input Offset Current IOS -40C TA +85C -40C TA +125C Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain CMRR AVO 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) 65 60 0 40 38 20 10 2 48 40 0.1 4 Conditions Min Typ 1 Max 6 7 60 100 1000 30 50 500 5 Unit 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 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 VOS/T IB/T IOS/T VOH VOL IOUT ISC ZOUT PSRR ISY 4 100 2000 25 4.9 4.875 4.965 25 30 60 45 76 45 65 85 100 125 SR BWP tS GBP M en en in 0.45 0.92 70 6 1000 67 42 38 <0.1 f = 1 kHz f = 10 kHz Rev. F | Page 5 of 20 AD8541/AD8542/AD8544 ABSOLUTE MAXIMUM RATINGS Table 4. Parameter Supply Voltage (VS) Input Voltage Differential Input Voltage1 Storage Temperature Range Operating Temperature Range Junction Temperature Range Lead Temperature (Soldering, 60 sec) 1 THERMAL RESISTANCE Rating 6V GND to VS 6 V -65C to +150C -40C to +125C -65C to +150C 300C JA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. Table 5. Package Type 5-Lead SC70 (KS) 5-Lead SOT-23 (RJ) 8-Lead SOIC (R) 8-Lead MSOP (RM) 8-Lead TSSOP (RU) 14-Lead SOIC (R) 14-Lead TSSOP (RU) JA 376 230 158 210 240 120 240 JC 126 146 43 45 43 36 43 Unit C/W C/W C/W C/W C/W C/W C/W For supplies less than 6 V, the differential input voltage is equal to VS. 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. ESD CAUTION Rev. F | Page 6 of 20 AD8541/AD8542/AD8544 TYPICAL PERFORMANCE CHARACTERISTICS 180 160 140 120 100 80 60 40 20 00935-005 VS = 5V VCM = 2.5V TA = 25C INPUT BIAS CURRENT (pA) 400 350 300 250 200 150 100 50 00935-008 00935-010 VS = 2.7V AND 5V VCM = VS/2 NUMBER OF AMPLIFIERS 0 -4.5 -3.5 -2.5 -1.5 -0.5 0.5 1.5 2.5 INPUT OFFSET VOLTAGE (mV) 3.5 4.5 0 -40 -20 0 20 40 60 80 TEMPERATURE (C) 100 120 140 Figure 5. Input Offset Voltage Distribution 1.0 0.5 INPUT OFFSET VOLTAGE (mV) Figure 8. Input Bias Current vs. Temperature 7 VS = 2.7V AND 5V VCM = VS/2 6 INPUT OFFSET CURRENT (pA) VS = 2.7V AND 5V VCM = VS/2 0 -0.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -35 -15 5 25 45 65 85 TEMPERATURE (C) 105 125 5 4 3 2 1 0 145 00935-006 -35 -15 5 25 45 65 85 TEMPERATURE (C) 105 125 145 Figure 6. Input Offset Voltage vs. Temperature 9 8 INPUT BIAS CURRENT (pA) VS = 2.7V AND 5V VCM = VS/2 POWER SUPPLY REJECTION (dB) Figure 9. Input Offset Current vs. Temperature 160 140 120 100 80 60 +PSRR -PSRR VS = 2.7V TA = 25C 7 6 5 4 3 2 1 0.5 1.5 2.5 3.5 COMMON-MODE VOLTAGE (V) 4.5 5.5 00935-007 40 20 0 -20 -40 100 1k 10k 100k FREQUENCY (Hz) 1M 10M 0 -0.5 Figure 7. Input Bias Current vs. Common-Mode Voltage Figure 10. Power Supply Rejection vs. Frequency Rev. F | Page 7 of 20 00935-009 -4.0 -55 -1 -55 AD8541/AD8542/AD8544 10k VS = 2.7V TA = 25C SMALL SIGNAL OVERSHOOT (%) 50 60 1k OUTPUT VOLTAGE (mV) VS = 2.7V RL = 10k TA = 25C +OS 100 SOURCE 10 SINK 40 30 -OS 1 20 0.1 10 0.01 0.1 1 LOAD CURRENT (mA) 10 100 10 100 1k CAPACITANCE (pF) 10k Figure 11. Output Voltage to Supply Rail vs. Load Current 3.0 Figure 14. Small Signal Overshoot vs. Load Capacitance 60 VS = 2.7V RL = 2k TA = 25C SMALL SIGNAL OVERSHOOT (%) 2.5 VS = 2.7V VIN = 2.5V p-p RL = 2k TA = 25C 50 OUTPUT SWING (V p-p) 2.0 40 +OS 1.5 30 -OS 1.0 20 0.5 10 1k 10k 100k FREQUENCY (Hz) 1M 10M 10 100 1k CAPACITANCE (pF) 10k Figure 12. Closed-Loop Output Voltage Swing vs. Frequency 60 VS = 2.7V RL = TA = 25C +OS Figure 15. Small Signal Overshoot vs. Load Capacitance SMALL SIGNAL OVERSHOOT (%) 50 40 VS = 2.7V RL = 100k CL = 300pF AV = 1 TA = 25C 30 -OS 1.35V 20 10 10 100 1k CAPACITANCE (pF) 10k 00935-013 0 50mV 10s Figure 13. Small Signal Overshoot vs. Load Capacitance Figure 16. Small Signal Transient Response Rev. F | Page 8 of 20 00935-016 00935-015 00935-012 0 0 00935-014 00935-011 0.01 0.001 0 AD8541/AD8542/AD8544 VS = 2.7V RL = 2k AV = 1 TA = 25C 90 80 COMMON-MODE REJECTION (dB) VS = 5V TA = 25C 70 60 50 40 30 20 10 0 1k 10k 100k FREQUENCY (Hz) 1M 10M 00935-020 1.35V 500mV 10s 00935-017 -10 Figure 17. Large Signal Transient Response 5 4 INPUT OFFSET VOLTAGE (mV) Figure 20. Common-Mode Rejection vs. Frequency VS = 2.7V RL = NO LOAD TA = 25C 80 3 2 1 0 -1 -2 -3 -4 VS = 5V RL = NO LOAD TA = 25C GAIN (dB) 60 40 20 0 45 90 135 180 PHASE SHIFT (Degrees) 00935-018 1k 10k 100k FREQUENCY (Hz) 1M 10M -5 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 COMMON-MODE VOLTAGE (V) Figure 18. Open-Loop Gain and Phase vs. Frequency 160 POWER SUPPLY REJECTION RATIO (dB) Figure 21. Input Offset Voltage vs. Common-Mode Voltage 10k 140 120 100 80 60 40 20 0 -20 VS = 5V TA = 25C OUTPUT VOLTAGE (mV) 1k VS = 5V TA = 25C 100 SOURCE SINK -PSRR +PSRR 10 1 0.1 00935-019 1k 10k 100k FREQUENCY (Hz) 1M 10M 0.01 0.1 1 LOAD CURRENT (mA) 10 100 Figure 19. Power Supply Rejection Ratio vs. Frequency Figure 22. Output Voltage to Supply Rail vs. Load Current Rev. F | Page 9 of 20 00935-021 -40 100 0.01 0.001 00935-040 AD8541/AD8542/AD8544 5.0 4.5 4.0 VS = 5V VIN = 4.9V p-p RL = NO LOAD TA = 25C 60 VS = 5V RL = 2k TA = 25C 3.5 3.0 2.5 2.0 1.5 1.0 0.5 00935-022 SMALL SIGNAL OVERSHOOT (%) 50 OUTPUT SWING (V p-p) 40 +OS 30 -OS 20 10 1k 10k 100k FREQUENCY (Hz) 1M 10M 10 100 1k CAPACITANCE (pF) 10k Figure 23. Closed-Loop Output Voltage Swing vs. Frequency, 5.0 4.5 4.0 Figure 26. Small Signal Overshoot vs. Load Capacitance 60 VS = 5V RL = TA = 25C 3.5 3.0 2.5 2.0 1.5 1.0 0.5 00935-023 SMALL SIGNAL OVERSHOOT (%) VS = 5V VIN = 4.9V p-p RL = 2k TA = 25C 50 OUTPUT SWING (V p-p) 40 +OS 30 -OS 20 10 1k 10k 100k FREQUENCY (Hz) 1M 10M 100 1k CAPACITANCE (pF) 10k Figure 24. Closed-Loop Output Voltage Swing vs. Frequency Figure 27. Small Signal Overshoot vs. Load Capacitance 60 VS = 5V RL = 10k TA = 25C SMALL SIGNAL OVERSHOOT (%) 50 VS = 5V RL = 100k CL = 300pF AV = 1 TA = 25C 40 +OS 30 -OS 20 2.5V 50mV 10 100 1k CAPACITANCE (pF) 10k 00935-024 10s 0 Figure 25. Small Signal Overshoot vs. Load Capacitance Figure 28. Small Signal Transient Response Rev. F | Page 10 of 20 00935-027 10 00935-026 0 0 10 00935-025 0 0 AD8541/AD8542/AD8544 VS = 5V RL = 2k AV = 1 TA = 25C VIN VOUT VS = 5V RL = 10k AV = 1 TA = 25C 2.5V 2.5V 00935-028 1V 10s 1V 20s Figure 29. Large Signal Transient Response 60 TA = 25C Figure 31. No Phase Reversal PHASE SHIFT (Degrees) 80 SUPPLY CURRENT/AMPLIFIER (A) VS = 5V RL = NO LOAD TA = 25C 50 GAIN (dB) 60 40 20 0 40 45 90 135 180 30 20 10 00935-029 1k 10k 100k FREQUENCY (Hz) 1M 10M 0 1 2 3 4 SUPPLY VOLTAGE (V) 5 6 Figure 30. Open-Loop Gain and Phase vs. Frequency Figure 32. Supply Current per Amplifier vs. Supply Voltage Rev. F | Page 11 of 20 00935-031 0 00935-030 AD8541/AD8542/AD8544 55 50 VS = 5V 45 40 VS = 2.7V 35 30 25 20 -55 00935-034 SUPPLY CURRENT/AMPLIFIER (A) VS = 5V MARKER SET @ 10kHz MARKER READING: 37.6nV/ Hz TA = 25C 00935-032 15nV/DIV 0 -35 -15 5 25 45 65 85 TEMPERATURE (C) 105 125 145 5 10 15 FREQUENCY (kHz) 20 25 Figure 33. Supply Current per Amplifier vs. Temperature 1000 900 800 700 VS = 2.7V AND 5V AV = 1 TA = 25C Figure 35. Voltage Noise IMPEDANCE () 600 500 400 300 200 100 10k 100k 1M FREQUENCY (Hz) 10M 100M 00935-033 0 1k Figure 34. Closed-Loop Output Impedance vs. Frequency Rev. F | Page 12 of 20 AD8541/AD8542/AD8544 THEORY OF OPERATION 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, including lower supply current for 1 MHz gain bandwidth, higher output current, and better performance at lower voltages. Higher Output Current 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 a 30 mA output current, sourcing, or sinking. Sourcing and sinking are strong at lower voltages, with 15 mA available at 2.7 V and 18 mA at 3.0 V. For even higher output currents, see the AD8531/AD8532/AD8534 parts for output currents to 250 mA. Information on these parts is available from your Analog Devices, Inc. representative, and data sheets are available at www.analog.com. Lower Supply Current for 1 MHz Gain Bandwidth The AD854x series typically uses 45 A of current per amplifier, which 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. Better Performance at Lower Voltages The AD854x family of parts was 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. Rev. F | Page 13 of 20 AD8541/AD8542/AD8544 APPLICATIONS NOTCH FILTER The AD854x have very high open-loop gain (especially with a supply voltage below 4 V), which makes it useful for active filters of all types. For example, Figure 36 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 can be designed with only one op amp if Q adjustment is not required. Simply remove U2 as illustrated in Figure 37. 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 causes 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 R 100k 3 2 R/2 50k C 26.7nF C 26.7nF 8 U1 4 Figure 38 is an example of the AD8544 in a notch filter circuit. The frequency dependent negative resistance (FDNR) notch filter has fewer critical matching requirements than the twin-T notch, where as the Q of the FDNR is directly proportional to a single resistor R1. Although matching component values is still important, it is also much easier and/or less expensive to accomplish in the FDNR circuit. For example, the twin-T notch uses three capacitors with two unique values, whereas the FDNR 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 9 10 1/4 AD8544 U3 8 VOUT VIN 2.5VREF C1 1F R 2.61k C2 1F R 2.61k R 2.61k R 2.61k 2.5VREF 13 12 3 2 4 U1 11 1/4 AD8544 1 1/4 AD8544 7 U2 6 5 1/2 AD8542 1 VIN 2.5VREF 2C 53.6F VOUT f= 1 2 LC1 1/4 AD8544 U4 14 NC 00935-037 L = R2C2 VIN 1/2 AD8542 7 U2 f0 = f0 = 1 2RC 1 5 6 R2 2.5k 2.5VREF Figure 38. FDNR 60 Hz Notch Filter with Output Buffer 2.5VREF Figure 36. 60 Hz Twin-T Notch Filter, Q = 10 5.0V R R 3 2 2C 7 U1 4 AD8541 6 VIN 2.5VREF VOUT 00935-035 R1 4 1- R1 + R2 R1 97.5k COMPARATOR FUNCTION A comparator function is a common application for a spare op amp in a quad package. Figure 39 illustrates 1/4 of the AD8544 as a comparator in a standard overload detection application. Unlike many op amps, the AD854x family can double as comparators because this op amp family has a 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 at 5 V and 5 s overload recovery time. R2 1M R1 1k R/2 00935-036 C C VIN 2.5VREF 2.5VDC VOUT 00935-038 Figure 37. 60 Hz Twin-T Notch Filter, Q = (Ideal) 1/4 AD8541 Figure 39. AD854x Comparator Application--Overload Detector Rev. F | Page 14 of 20 AD8541/AD8542/AD8544 PHOTODIODE APPLICATION The AD854x family has very high impedance with an 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 that can be removed by capacitive coupling or software calibration. Figure 40 illustrates a photodiode or current measurement application. The feedback resistor is limited to 10 M to avoid excessive output offset. In addition, 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 best performance, follow the standard high impedance layout techniques, which include the following: * * * * Shielding the circuit. Cleaning the circuit board. Putting a trace connected to the noninverting input around the inverting input. Using separate analog and digital power supplies. C 100pF R 10M OR V+ 2 3 D 4 7 6 VOUT AD8541 00935-039 2.5VREF 2.5VREF Figure 40. High Input Impedance Application--Photodiode Amplifier Rev. F | Page 15 of 20 AD8541/AD8542/AD8544 OUTLINE DIMENSIONS 2.90 BSC 5.10 5.00 4.90 4 5 1.60 BSC 1 2 3 2.80 BSC 4.50 4.40 4.30 14 8 PIN 1 0.95 BSC 1.30 1.15 0.90 1.90 BSC 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 1.45 MAX 0.22 0.08 10 5 0 0.60 0.45 0.30 0.20 0.09 0.15 MAX 0.50 0.30 SEATING PLANE SEATING COPLANARITY PLANE 0.10 8 0 0.75 0.60 0.45 COMPLIANT TO JEDEC STANDARDS MO-153-AB-1 COMPLIANT TO JEDEC STANDARDS MO-178-A A Figure 41. 5-Lead Small Outline Transistor Package [SOT-23] (RJ-5) Dimensions shown in millimeters Figure 42. 14-Lead Thin Shrink Small Outline Package [TSSOP] (RU-14) Dimensions shown in millimeters 2.20 2.00 1.80 1.35 1.25 1.15 PIN 1 1.00 0.90 0.70 5 1 2 4 3 8.75 (0.3445) 8.55 (0.3366) 14 1 8 7 2.40 2.10 1.80 4.00 (0.1575) 3.80 (0.1496) 6.20 (0.2441) 5.80 (0.2283) 0.65 BSC 1.10 0.80 0.40 0.10 0.46 0.36 0.26 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0039) COPLANARITY 0.10 0.51 (0.0201) 0.31 (0.0122) 1.75 (0.0689) 1.35 (0.0531) SEATING PLANE 0.50 (0.0197) 0.25 (0.0098) 8 0 0.25 (0.0098) 0.17 (0.0067) 1.27 (0.0500) 0.40 (0.0157) 45 0.10 MAX 0.30 0.15 SEATING PLANE 0.22 0.08 0.10 COPLANARITY COMPLIANT TO JEDEC STANDARDS MO-203-AA COMPLIANT TO JEDEC STANDARDS MS-012-AB 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 43. 5-Lead Thin Shrink Small Outline Transistor Package [SC70] (KS-5) Dimensions shown in millimeters Figure 44. 14-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-14) Dimensions shown in millimeters and (inches) Rev. F | Page 16 of 20 060606-A AD8541/AD8542/AD8544 3.20 3.00 2.80 3.10 3.00 2.90 3.20 3.00 2.80 PIN 1 8 5 1 5.15 4.90 4.65 8 5 4 4.50 4.40 4.30 1 4 6.40 BSC 0.65 BSC 0.95 0.85 0.75 0.15 0.00 0.38 0.22 SEATING PLANE 1.10 MAX 8 0 0.80 0.60 0.40 PIN 1 0.65 BSC 0.15 0.05 COPLANARITY 0.10 0.30 0.19 1.20 MAX SEATING 0.20 PLANE 0.09 0.23 0.08 8 0 COPLANARITY 0.10 0.75 0.60 0.45 COMPLIANT TO JEDEC STANDARDS MO-153-AA COMPLIANT TO JEDEC STANDARDS MO-187-AA Figure 45. 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions shown in millimeters 5.00 (0.1968) 4.80 (0.1890) Figure 46. 8-Lead Thin Shrink Small Outline Package [TSSOP] (RU-8) Dimensions shown in millimeters 4.00 (0.1574) 3.80 (0.1497) 8 1 5 4 6.20 (0.2441) 5.80 (0.2284) 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) COPLANARITY 0.10 SEATING PLANE 1.75 (0.0688) 1.35 (0.0532) 0.50 (0.0196) 0.25 (0.0099) 8 0 0.25 (0.0098) 0.17 (0.0067) 1.27 (0.0500) 0.40 (0.0157) 45 0.51 (0.0201) 0.31 (0.0122) COMPLIANT TO JEDEC STANDARDS MS-012-A A 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 47. 8-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-8) Dimensions shown in millimeters and (inches) Rev. F | Page 17 of 20 012407-A AD8541/AD8542/AD8544 ORDERING GUIDE Model AD8541AKS-R2 AD8541AKS-REEL7 AD8541AKSZ-R2 1 AD8541AKSZ-REEL71 AD8541ART-R2 AD8541ART-REEL AD8541ART-REEL7 AD8541ARTZ-R21 AD8541ARTZ-REEL1 AD8541ARTZ-REEL71 AD8541AR AD8541AR-REEL AD8541AR-REEL7 AD8541ARZ1 AD8541ARZ-REEL1 AD8541ARZ-REEL71 AD8542AR AD8542AR-REEL AD8542AR-REEL7 AD8542ARZ1 AD8542ARZ-REEL1 AD8542ARZ-REEL71 AD8542ARM-R2 AD8542ARM-REEL AD8542ARMZ-R21 AD8542ARMZ-REEL1 AD8542ARU AD8542ARU-REEL AD8542ARUZ1 AD8542ARUZ-REEL1 AD8544AR AD8544AR-REEL AD8544AR-REEL7 AD8544ARZ1 AD8544ARZ-REEL1 AD8544ARZ-REEL71 AD8544ARU AD8544ARU-REEL AD8544ARUZ1 AD8544ARUZ-REEL1 1 Temperature Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package Description 5-Lead SC70 5-Lead SC70 5-Lead SC70 5-Lead SC70 5-Lead SOT-23 5-Lead SOT-23 5-Lead SOT-23 5-Lead SOT-23 5-Lead SOT-23 5-Lead SOT-23 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead MSOP 8-Lead MSOP 8-Lead MSOP 8-Lead MSOP 8-Lead TSSOP 8-Lead TSSOP 8-Lead TSSOP 8-Lead TSSOP 14-Lead SOIC_N 14-Lead SOIC_N 14-Lead SOIC_N 14-Lead SOIC_N 14-Lead SOIC_N 14-Lead SOIC_N 14-Lead TSSOP 14-Lead TSSOP 14-Lead TSSOP 14-Lead TSSOP Package Option KS-5 KS-5 KS-5 KS-5 RJ-5 RJ-5 RJ-5 RJ-5 RJ-5 RJ-5 R-8 R-8 R-8 R-8 R-8 R-8 R-8 R-8 R-8 R-8 R-8 R-8 RM-8 RM-8 RM-8 RM-8 RU-8 RU-8 RU-8 RU-8 R-14 R-14 R-14 R-14 R-14 R-14 RU-14 RU-14 RU-14 RU-14 Branding A4B A4B A12 A12 A4A A4A A4A A4A# A4A# A4A# AVA AVA AVA# AVA# Z = RoHS Compliant Part; # denotes RoHS compliant product may be top or bottom marked. Rev. F | Page 18 of 20 AD8541/AD8542/AD8544 NOTES Rev. F | Page 19 of 20 AD8541/AD8542/AD8544 NOTES (c)2008 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D00935-0-1/08(F) Rev. F | Page 20 of 20 |
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