Datasheet

ManualsBrandsANALOG DEVICES ManualsLinear ICsLinear IC - Op-amp Multi-purpose MSOP 8

Micropower, RRIO, CMOS, 18 V

Operational Amplifier

AD8546

Rev. A

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FEATURES

Micropower at high voltage (18 V): 22 µA max

Low input bias current: 20 pA max

Gain bandwidth product: 200 kHz

Slew rate: 70 V/ms

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

PIN CONFIGURATION

OUT A

–IN A

+IN A

V–

V+

OUT B

–IN B

+IN B

AD8546

TOP VIEW

(Not to Scale)

09585-001

Figure 1. 8-Lead MSOP

GENERAL DESCRIPTION

The AD8546 is a dual, micropower, high input impedance

amplifier optimized for low power and wide operating supply

voltage range applications.

The AD8546 RRIO provides increased dynamic range to drive

low frequency data converters, which is ideal for dc gain and

buffering of sensor front ends or high impedance input sources

in wireless or remote sensors or transmitters.

The AD8546 specification of low supply current (22 µA) over

the wide range of operating voltage 2.7 V to 18 V or dual

supplies (±1.35 V to ±9 V) makes it 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 is specified over the extended industrial temperature

range of −40°C to +125°C and is available in an 8-lead MSOP.

Table 1. Micropower Op Amps

Amplifier

Supply Voltage

5 V 12 V to 16 V 36 V

Single AD8500 AD8663

ADA4505-1

AD8505

AD8541

AD8603

Dual AD8502 AD8667 OP295

ADA4505-2 AD8657 ADA4062-2

AD8506 OP281

AD8542

AD8607

Quad AD8504 AD8669 OP495

ADA4505-4 ADA4062-4

AD8508 OP481

AD8544

AD8609

See www.analog.com for the latest selection of micropower op amps.

Summary of content (24 pages)

PAGE 1
Micropower, RRIO, CMOS, 18 V Operational Amplifier AD8546 PIN CONFIGURATION Micropower at high voltage (18 V): 22 µA max Low input bias current: 20 pA max Gain bandwidth product: 200 kHz Slew rate: 70 V/ms Single-supply operation: 2.7 V to 18 V Dual-supply operation: ±1.35 V to ±9 V Unity-gain stable OUT A 1 –IN A 2 AD8546 +IN A 3 TOP VIEW (Not to Scale) V– 4 8 V+ 7 OUT B 6 –IN B 5 +IN B 09585-001 FEATURES Figure 1.
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AD8546 TABLE OF CONTENTS Features .............................................................................................. 1 Typical Performance Characteristics ..............................................7 Applications ....................................................................................... 1 Applications Information .............................................................. 17 Pin Configuration .............................................................................
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AD8546 SPECIFICATIONS ELECTRICAL CHARACTERISTICS—2.7 V OPERATION VSY = 2.7 V, VCM = VSY/2, TA = 25°C, unless otherwise specified. Table 2. Parameter INPUT CHARACTERISTICS Offset Voltage Input Bias Current Symbol Test Conditions/Comments VOS VCM = 0 V to 2.7 V VCM = 0.3 V to 2.4 V; −40°C ≤ TA ≤ +85°C VCM = 0 V to 2.7 V; −40°C ≤ TA ≤ +85°C VCM = 0.3 V to 2.4 V; −40°C ≤ TA ≤ +125°C VCM = 0 V to 2.7 V; −40°C ≤ TA ≤ +125°C Min Typ 3 10 CINDM CINCM 3.5 3.
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AD8546 ELECTRICAL CHARACTERISTICS—10 V OPERATION VSY = 10 V, VCM = VSY/2, TA = 25°C, unless otherwise specified. Table 3. Parameter INPUT CHARACTERISTICS Offset Voltage Input Bias Current Symbol Test Conditions/Comments VOS VCM = 0 V to 10 V VCM = 0.3 V to 9.7 V; −40°C ≤ TA ≤ +85°C VCM = 0 V to 10 V; −40°C ≤ TA ≤ +85°C VCM = 0.3 V to 9.7 V; −40°C ≤ TA ≤ +125°C VCM = 0 V to 10 V; −40°C ≤ TA ≤ +125°C Min Typ 3 10 CINDM CINCM 3.5 3.
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AD8546 ELECTRICAL CHARACTERISTICS—18 V OPERATION VSY = 18 V, VCM = VSY/2, TA = 25°C, unless otherwise specified. Table 4. Parameter INPUT CHARACTERISTICS Offset Voltage Input Bias Current Symbol Test Conditions/Comments VOS VCM = 0 V to 18 V VCM = 0.3 V to 17.7 V; −40°C ≤ TA ≤ +85°C VCM = 0 V to 18 V; −40°C ≤ TA ≤ +85°C VCM = 0.3 V to 17.7 V; −40°C ≤ TA ≤ +125°C VCM = 0 V to 18 V; −40°C ≤ TA ≤ +125°C Min Typ 3 10 CINDM CINCM 3.5 10.
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AD8546 ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE Table 5. Parameter Supply Voltage Input Voltage Input Current1 Differential Input Voltage Output Short-Circuit Duration to GND Storage Temperature Range Operating Temperature Range Junction Temperature Range Lead Temperature (Soldering, 60 sec) 1 Rating 20.
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AD8546 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. 40 40 NUMBER OF AMPLIFIERS 30 25 20 15 10 30 25 20 15 10 0 0 VOS (mV) 09585-002 5 –2.4 –2.2 –2.0 –1.8 –1.6 –1.4 –1.2 –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 5 VOS (mV) Figure 2. Input Offset Voltage Distribution Figure 5. Input Offset Voltage Distribution 12 12 VSY = 18V –40°C ≤ TA ≤ +125°C VSY = 2.7V –40°C ≤ TA ≤ +125°C 4.0 Figure 6. Input Offset Voltage Drift Distribution 3.
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AD8546 3.0 3.0 VSY = 2.7V –40°C ≤ TA ≤ +85°C 2.0 2.0 1.5 1.5 1.0 1.0 0.5 0.5 0 –0.5 –1.0 0 –0.5 –1.5 –1.5 –2.0 –2.0 –2.5 –2.5 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 VCM (V) –3.0 09585-008 0 0 4 6 8 10 12 14 16 18 VCM (V) Figure 8. Input Offset Voltage vs. Common-Mode Voltage Figure 11. Input Offset Voltage vs. Common-Mode Voltage 3.0 8.0 7.0 VSY = 2.7V –40°C ≤ TA ≤ +125°C 2.5 2 09585-011 –1.0 –3.0 VSY = 18V –40°C ≤ TA ≤ +125°C 6.0 2.0 5.0 1.5 4.0 1.0 3.
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AD8546 4 4 VSY = 18V 3 2 2 1 1 125°C 85°C 25°C –1 –2 –2 –3 –3 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 VCM (V) –4 0 2 4 6 8 10 12 14 16 Figure 17. Input Bias Current vs. Common-Mode Voltage 10 10 OUTPUT VOLTAGE (VOH) TO SUPPLY RAIL (V) Figure 14. Input Bias Current vs. Common-Mode Voltage VSY = 2.7V 1 –40°C +25°C +85°C +125°C 100m 10m 1m 0.1m 0.01m 0.001 0.01 0.1 1 LOAD CURRENT (mA) 10 100 18 VCM (V) VSY = 18V 1 –40°C +25°C +85°C +125°C 100m 10m 1m 0.1m 0.
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AD8546 18.000 2.700 RL = 1MΩ RL = 1MΩ OUTPUT VOLTAGE, VOH (V) 2.698 2.697 RL = 100kΩ 17.990 17.985 RL = 100kΩ 17.980 2.696 –25 0 25 50 75 100 09585-020 2.695 –50 17.975 –50 125 TEMPERATURE (°C) 0 25 75 100 125 Figure 23. Output Voltage (VOH) vs. Temperature 6 12 VSY = 18V VSY = 2.7V 5 4 3 RL = 100kΩ 2 RL = 100kΩ 8 6 4 2 RL = 1MΩ RL = 1MΩ –25 0 25 50 75 100 125 TEMPERATURE (°C) 0 –50 09585-021 0 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) Figure 21.
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AD8546 60 35 30 50 VSY = 2.7V VSY = 18V 40 ISY PER AMP (µA) ISY PER AMP (µA) 25 20 15 30 20 10 –40°C +25°C 5 10 +85°C 9 12 15 18 VSY (V) 0 –50 135 0 –45 –20 CL = 10pF –90 CL = 100pF 10k –135 1M 100k 100 VSY = 18V RL = 1MΩ 40 90 20 45 0 0 GAIN –45 –20 CL = 10pF FREQUENCY (Hz) –90 CL = 100pF –60 1k 10k –135 1M 100k FREQUENCY (Hz) Figure 30. Open-Loop Gain and Phase vs. Frequency Figure 27. Open-Loop Gain and Phase vs. Frequency 60 60 VSY = 2.
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AD8546 1000 1000 AV = +100 AV = +100 AV = +10 AV = +10 100 100 AV = +1 ZOUT (Ω) ZOUT (Ω) AV = +1 10 10 VSY = 2.7V 1k 10k FREQUENCY (Hz) 100k 09585-032 100 1 100 Figure 32. Output Impedance vs. Frequency 140 VSY = 2.7V VCM = 2.4V 80 60 80 60 40 40 20 20 1k 10k 100k 1M FREQUENCY (Hz) 0 100 1k 10k 100k Figure 33. CMRR vs. Frequency Figure 36. CMRR vs.
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AD8546 70 70 VSY = 2.7V VIN = 10mV p-p RL = 1MΩ 60 60 50 OVERSHOOT (%) 50 40 30 OS+ OS– 20 40 30 20 OS+ OS– 100 1000 CAPACITANCE (pF) 0 10 09585-038 100 1000 CAPACITANCE (pF) Figure 38. Small Signal Overshoot vs. Load Capacitance Figure 41. Small Signal Overshoot vs. Load Capacitance VSY = ±1.35V AV = +1 RL = 1MΩ CL = 100pF TIME (100µs/DIV) 09585-042 09585-039 VOLTAGE (5V/DIV) VOLTAGE (500mV/DIV) VSY = ±9V AV = +1 RL = 1MΩ CL = 100pF TIME (100µs/DIV) Figure 39.
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AD8546 INPUT INPUT 0 2 INPUT VOLTAGE (V) VSY = ±1.35V AV = –10 RL = 1MΩ –0.4 OUTPUT VOLTAGE (V) –1 –2 10 1 5 OUTPUT OUTPUT 0 TIME (40µs/DIV) TIME (40µs/DIV) Figure 44. Positive Overload Recovery Figure 47. Positive Overload Recovery VSY = ±1.35V AV = –10 RL = 1MΩ 0.4 VSY = ±9V AV = –10 RL = 1MΩ 2 0.2 0 INPUT 0 OUTPUT 0 –5 –2 –10 09585-045 –1 TIME (40µs/DIV) TIME (40µs/DIV) Figure 45. Negative Overload Recovery Figure 48.
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AD8546 VSY = 18V RL = 100kΩ CL = 10pF VOLTAGE (500mV/DIV) VOLTAGE (500mV/DIV) VSY = 2.7V RL = 100kΩ CL = 10pF INPUT +5mV OUTPUT 0 ERROR BAND INPUT +5mV OUTPUT –5mV TIME (10µs/DIV) Figure 50. Negative Settling Time to 0.1% Figure 53. Negative Settling Time to 0.1% 1000 1000 VSY = 18V 100 1 100 1k 10k FREQUENCY (Hz) 100k 1M 1 10 Figure 51. Voltage Noise Density vs. Frequency 100 1k 10k FREQUENCY (Hz) 100k 1M Figure 54. Voltage Noise Density vs.
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AD8546 20 3.0 VSY = 2.7V VIN = 2.6V RL = 1MΩ AV = +1 16 OUTPUT SWING (V) OUTPUT SWING (V) 2.5 VSY = 18V VIN = 17.9V RL = 1MΩ AV = +1 18 2.0 1.5 1.0 14 12 10 8 6 4 0.5 100 1k 10k 100k 1M FREQUENCY (Hz) 0 09585-056 0 10 10 100 Figure 56. Output Swing vs. Frequency 100k 1M 100 VSY = 18V VIN = 0.5V rms RL = 1MΩ AV = +1 VSY = 2.7V VIN = 0.2V rms RL = 1MΩ AV = +1 10 THD + N (%) 10 1 0.1 100 1k 10k 100k FREQUENCY (Hz) 0.01 10 09585-057 0.
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AD8546 APPLICATIONS INFORMATION The AD8546 is a low input bias current, micropower CMOS amplifier that operates over a wide supply voltage range of 2.7 V to 18 V. The AD8546 also employs unique input and output stages to achieve a rail-to-rail input and output range with a very low supply current. drain impedances contributes to the offset voltage of the amplifier. This problem is exacerbated at high temperatures due to the decrease in the threshold voltage of the input transistors.
PAGE 18
AD8546 The AD8546 features a complementary output stage consisting of the M16 and M17 transistors (see Figure 62). These transistors are configured in Class AB topology and are biased by the voltage source, VB2. This topology allows the output voltage to go within millivolts of the supply rails, achieving a rail-to-rail output swing. The output voltage is limited by the output impedance of the transistors, which are low RON MOS devices.
PAGE 19
AD8546 The AD8546 has input devices that are protected from large differential input voltages by Diode D1 and Diode D2 (see Figure 62). These diodes consist of substrate PNP bipolar transistors and conduct whenever the differential input voltage exceeds approximately 600 mV; however, these diodes also allow a current path from the input to the lower supply rail, thus resulting in an increase in the total supply current of the system. As shown in Figure 70, both configurations yield the same result.
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AD8546 With a zero-scale input, a current of VREF/RNULL flows through R. This creates a current flowing through the sense resistor, ISENSE, determined by the following equation: ISENSE, MIN = (VREF × R)/(RNULL × RSENSE) The AD8546 and ADR125 together consume only 160 µA quiescent current, making 3.34 mA current available to power additional signal conditioning circuitry or to power a bridge circuit.
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AD8546 OUTLINE DIMENSIONS 3.20 3.00 2.80 8 3.20 3.00 2.80 1 5.15 4.90 4.65 5 4 PIN 1 IDENTIFIER 0.65 BSC 0.95 0.85 0.75 15° MAX 1.10 MAX 0.40 0.25 6° 0° 0.23 0.09 COMPLIANT TO JEDEC STANDARDS MO-187-AA 0.80 0.55 0.40 10-07-2009-B 0.15 0.05 COPLANARITY 0.10 Figure 72.
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AD8546 NOTES Rev.
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AD8546 NOTES Rev.