Datasheet AD8220 (Analog Devices) - 25
| 制造商 | Analog Devices |
| 描述 | JFET Input Instrumentation Amplifier with Rail-to-Rail Output in MSOP Package |
| 页数 / 页 | 28 / 25 — Data Sheet. AD8220. ELECTROCARDIOGRAM SIGNAL CONDITIONING. G = +50. … |
| 修订版 | C |
| 文件格式/大小 | PDF / 794 Kb |
| 文件语言 | 英语 |
Data Sheet. AD8220. ELECTROCARDIOGRAM SIGNAL CONDITIONING. G = +50. LOW-PASS FIFTH ORDER FILTER AT 157Hz. INSTRUMENTATION
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Data Sheet AD8220 ELECTROCARDIOGRAM SIGNAL CONDITIONING
In addition, the AD8220 JFET inputs have ultralow input The AD8220 makes an excellent input amplifier for next bias current and no current noise, making it useful for ECG generation ECGs. Its small size, high CMRR over frequency, applications where there are often large impedances. The MSOP rail-to-rail output, and JFET inputs are well suited for this and the optimal pinout of the AD8220 allow smaller footprints application. Potentials measured on the skin range from 0.2 mV and more efficient layout, paving the way for next-generation to 2 mV. The AD8220 solves many of the typical challenges of portable ECGs. measuring these body surface potentials. The high CMRR of Figure 67 shows an example ECG schematic. Following the the AD8220 helps reject common-mode signals that come in AD8220 is a 0.033 Hz high-pass filter, formed by the 4.7 µF the form of line noise or high frequency EMI from equipment capacitor and the 1 MΩ resistor, which removes the dc offset in the operating room. Its rail-to-rail output offers a wide that develops between the electrodes. An additional gain of 50, dynamic range al owing for higher gains than would be possible provided by the AD8618, makes use of the 0 V to 5 V input using other instrumentation amplifiers. JFET inputs offer a range of the ADC. An active, fifth-order, low-pass Bessel filter large input capacitance of 5 pF. A natural RC filter is formed removes signals greater than approximately 160 Hz. An OP2177 reducing high frequency noise when series input resistors are buffers, inverts, and gains the common-mode voltage taken at used in front of the AD8220 (see the RF Interference section). the midpoint of the AD8220 gain setting resistors. This right- leg drive circuit helps cancel common-mode signals by inverting the common-mode signal and driving it back into the body. A 499 kΩ series resistor at the output of the OP2177 limits the current driven into the body.
G = +50 LOW-PASS FIFTH ORDER FILTER AT 157Hz INSTRUMENTATION AMPLIFIER 1.18k G = +14 Ω 57.6kΩ 14kΩ 14k 19.3k Ω Ω 33nF 14.5kΩ 68nF +5V 2.5V 2.2pF 47nF AD8220 HIGH-PASS FILTER 0.033Hz AD8618 AD8618 15kΩ +5V AD7685 +5V +5V +5V +5V A B 10kΩ 500Ω 24.9kΩ 19.3kΩ 14.5kΩ ADC 4.12k 10pF Ω –5V AD8618 +5V 2.7nF 24.9kΩ 4.7µF 4.7µF AD8618 REF 1.15k 10kΩ Ω +5V –5V 220pF 1MΩ 2.2pF 33nF +5V 4.99kΩ 22nF REFERENCE ADR435 –5V 2.5V 2.5V 2.5V 2.5V OP2177 C –5V OP AMPS 68pF 12.7kΩ 866kΩ +5V 499kΩ OP2177
032
–5V
03579- Figure 67. Example ECG Schematic Rev. C | Page 25 of 28 Document Outline FEATURES APPLICATIONS PIN CONFIGURATION GENERAL DESCRIPTION REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION GAIN SELECTION LAYOUT Common-Mode Rejection Ratio (CMRR) Grounding REFERENCE TERMINAL POWER SUPPLY REGULATION AND BYPASSING INPUT BIAS CURRENT RETURN PATH INPUT PROTECTION RF INTERFERENCE COMMON-MODE INPUT VOLTAGE RANGE DRIVING AN ADC APPLICATIONS INFORMATION AC-COUPLED INSTRUMENTATION AMPLIFIER DIFFERENTIAL OUTPUT ELECTROCARDIOGRAM SIGNAL CONDITIONING OUTLINE DIMENSIONS ORDERING GUIDE AUTOMOTIVE PRODUCTS
Data Sheet AD8220 ELECTROCARDIOGRAM SIGNAL CONDITIONING
In addition, the AD8220 JFET inputs have ultralow input The AD8220 makes an excellent input amplifier for next bias current and no current noise, making it useful for ECG generation ECGs. Its small size, high CMRR over frequency, applications where there are often large impedances. The MSOP rail-to-rail output, and JFET inputs are well suited for this and the optimal pinout of the AD8220 allow smaller footprints application. Potentials measured on the skin range from 0.2 mV and more efficient layout, paving the way for next-generation to 2 mV. The AD8220 solves many of the typical challenges of portable ECGs. measuring these body surface potentials. The high CMRR of Figure 67 shows an example ECG schematic. Following the the AD8220 helps reject common-mode signals that come in AD8220 is a 0.033 Hz high-pass filter, formed by the 4.7 µF the form of line noise or high frequency EMI from equipment capacitor and the 1 MΩ resistor, which removes the dc offset in the operating room. Its rail-to-rail output offers a wide that develops between the electrodes. An additional gain of 50, dynamic range al owing for higher gains than would be possible provided by the AD8618, makes use of the 0 V to 5 V input using other instrumentation amplifiers. JFET inputs offer a range of the ADC. An active, fifth-order, low-pass Bessel filter large input capacitance of 5 pF. A natural RC filter is formed removes signals greater than approximately 160 Hz. An OP2177 reducing high frequency noise when series input resistors are buffers, inverts, and gains the common-mode voltage taken at used in front of the AD8220 (see the RF Interference section). the midpoint of the AD8220 gain setting resistors. This right- leg drive circuit helps cancel common-mode signals by inverting the common-mode signal and driving it back into the body. A 499 kΩ series resistor at the output of the OP2177 limits the current driven into the body.
G = +50 LOW-PASS FIFTH ORDER FILTER AT 157Hz INSTRUMENTATION AMPLIFIER 1.18k G = +14 Ω 57.6kΩ 14kΩ 14k 19.3k Ω Ω 33nF 14.5kΩ 68nF +5V 2.5V 2.2pF 47nF AD8220 HIGH-PASS FILTER 0.033Hz AD8618 AD8618 15kΩ +5V AD7685 +5V +5V +5V +5V A B 10kΩ 500Ω 24.9kΩ 19.3kΩ 14.5kΩ ADC 4.12k 10pF Ω –5V AD8618 +5V 2.7nF 24.9kΩ 4.7µF 4.7µF AD8618 REF 1.15k 10kΩ Ω +5V –5V 220pF 1MΩ 2.2pF 33nF +5V 4.99kΩ 22nF REFERENCE ADR435 –5V 2.5V 2.5V 2.5V 2.5V OP2177 C –5V OP AMPS 68pF 12.7kΩ 866kΩ +5V 499kΩ OP2177
032
–5V
03579- Figure 67. Example ECG Schematic Rev. C | Page 25 of 28 Document Outline FEATURES APPLICATIONS PIN CONFIGURATION GENERAL DESCRIPTION REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION GAIN SELECTION LAYOUT Common-Mode Rejection Ratio (CMRR) Grounding REFERENCE TERMINAL POWER SUPPLY REGULATION AND BYPASSING INPUT BIAS CURRENT RETURN PATH INPUT PROTECTION RF INTERFERENCE COMMON-MODE INPUT VOLTAGE RANGE DRIVING AN ADC APPLICATIONS INFORMATION AC-COUPLED INSTRUMENTATION AMPLIFIER DIFFERENTIAL OUTPUT ELECTROCARDIOGRAM SIGNAL CONDITIONING OUTLINE DIMENSIONS ORDERING GUIDE AUTOMOTIVE PRODUCTS