AD8270 Analog Devices, AD8270 Datasheet
AD8270
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AD8270 Summary of contents
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... It can also be configured in over 40 single- ended configurations, with gains ranging from −2 to +3. The AD8270 is the first dual-difference amplifier in the small 4 mm × LFCSP. It requires the same board area as a typical single-difference amplifier. The smaller package allows a 2× ...
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... Maximum Power Dissipation ..................................................... 5 ESD Caution.................................................................................. 5 Pin Configuration and Function Descriptions............................. 6 Typical Performance Characteristics ............................................. 7 Theory of Operation ...................................................................... 13 REVISION HISTORY 1/08—Revision 0: Initial Version Circuit Information.................................................................... 13 Driving the AD8270................................................................... 13 Package Considerations............................................................. 13 Power Supplies............................................................................ 13 Input Voltage Range................................................................... 14 Applications Information .............................................................. 15 Difference Amplifier Configurations ...................................... 15 Single-Ended Configurations ................................................... 15 Differential Output .................................................................... 17 Driving an ADC ...
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... AD8270 Unit MHz V/μ μV p-p nV/√Hz % ppm/°C μV μV/°C dB μV/V V kΩ ...
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... AD8270 V = ± 25° REF A LOAD Table 3. Parameter DYNAMIC PERFORMANCE Bandwidth Slew Rate Settling Time to 0.01% Settling Time to 0.001% NOISE/DISTORTION Harmonic Distortion 1 Voltage Noise GAIN Gain Error Gain Drift INPUT CHARACTERISTICS 2 Offset Average Temperature Drift Common-Mode Rejection Ratio Power Supply Rejection Ratio ...
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... MAXIMUM POWER DISSIPATION Rating The maximum safe power dissipation for the AD8270 is limited ± the associated rise in junction temperature (T See derating approximately 130°C, which is the glass transition temperature, curve in Figure 2 the plastic changes its properties ...
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... Resistor Connected to Negative Terminal of Op Amp B. 13 −V Negative Supply OUTB Op Amp B Output. 15 OUTA Op Amp A Output Positive Supply. S PIN 1 INDICATOR 12 –IN1B –IN1A 1 AD8270 11 –IN2B –IN2A 2 TOP VIEW +IN2A 3 10 +IN2B (Not to Scale) +IN1A 4 9 +IN1B Figure 3. Pin Configuration Rev Page ...
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... Figure 8. Common-Mode Input Voltage vs. Output Voltage, Gain = 0.5, ±5 V and ±2.5 V Supplies 20 (0, +15) 15 (–14.3, +7.85 –5 –10 (–14.3, –7.85) –15 (0, –15) –20 –20 –15 –10 – OUTPUT VOLTAGE (V) Figure 9. Common-Mode Input Voltage vs. Output Voltage, Gain = 1, ±15 V Supplies AD8270 (+7.5, +7.5) (+7.5, –7.5) 10 (+2.5, +2.5) = ±5 S (+2.5, –2. (+14.3, +7.85) (+14.3, –7.85 ...
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... AD8270 6 (0, +5) 4 (–4.3, +2.85) (0, +2.5) 2 (–1.6, +1. ±2 (–1.6, –1.7) –2 (0, –2.5) (–4.3, –2.85) (–4.3, +2.85) –4 (0, –5) –6 –5 –4 –3 –2 – OUTPUT VOLTAGE (V) Figure 10. Common-Mode Input Voltage vs. Output Voltage, Gain = 1, ±5 V and ±2.5 V Supplies 20 (0, +15) 15 (–14.3, +11.4) ...
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... TEMPERATURE (°C) +125°C +85°C –40°C +25°C +125°C +85°C +25° (Ω) LOAD Figure 20. Output Voltage Swing vs. R LOAD –40°C +125°C +85°C +125°C +85°C +25°C –40° CURRENT (mA) OUT AD8270 120 10k +25° ...
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... AD8270 V = ±15V S 100pF 18pF 0pF 1µs/DIV Figure 22. Small Signal Step Response, Gain = 0 ±15V S 220pF 33pF 0pF 1µs/DIV Figure 23. Small Signal Step Response, Gain = ±15V S 470pF 0pF 100pF 1µs/DIV Figure 24. Small Signal Step Response, Gain = 2 160 140 120 V = ± ...
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... Figure 31. Output Slew Rate vs. Temperature 1k GAIN = 2 100 GAIN = 0 Figure 32. Voltage Noise Spectral Density vs. Frequency, Referred to Output GAIN = 2 GAIN = 1 GAIN = 1/2 1µV/DIV Figure 33. 0 Voltage Noise, Referred to Output Rev Page AD8270 105 115 125 GAIN = 1 100 1k 10k ...
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... AD8270 210 180 150 120 –600 –400 –200 0 V (µV) OSI Figure 34. Typical Distribution of Op Amp Voltage Offset 100 310 315 320 325 330 I (nA) BIAS Figure 35. Typical Distribution of Op Amp Bias Current 160 140 120 100 ...
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... It can be farther away from the supply pins and, typically, it can be shared by other precision integrated circuits. The AD8270 is specified at ±15 V and ±5 V, but it can be used with unbalanced supplies, as well. For example, −V The difference between the two supplies must be kept below 36 V. ...
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... AD8270 INPUT VOLTAGE RANGE The AD8270 has a true rail-to-rail input range for the majority of applications. Because most AD8270 configurations divide down the voltage before they reach the internal op amp, the op amp sees only a fraction of the input voltage. Figure 41 shows an example of how the voltage division works in the difference amplifier configuration ...
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... Gain of 2, Referenced to Midsupply −IN SINGLE-ENDED CONFIGURATIONS The AD8270 can be configured for a wide variety of single- ended configurations with gains ranging from −2 to +3. Table 8 shows a subset of the possible configurations. Many signal gains have more than one configuration choice, which allows freedom in choosing the op amp closed-loop gain. ...
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... AD8270 Table 8. Selected Single-Ended Configurations Electrical Performance Op Amp Closed-Loop Gain Signal Gain −2 3 −1.5 3 −1.4 3 −1.25 3 −1 3 −0.8 3 −0.667 2 −0.6 2 −0.5 2 −0.333 2 −0.25 1.5 −0.2 1.5 −0.125 1.5 +0.1 1.5 +0.2 2 +0.25 1.5 +0.3 1.5 +0.333 2 +0.375 1.5 +0.4 2 +0.5 3 +0.5 1.5 +0.6 3 +0.6 1.5 +0.625 1.5 +0.667 2 +0.7 1.5 +0.75 3 +0.75 1.5 +0.8 2 +0.9 1.5 +1 1 +1.125 1.5 +1.2 3 +1.2 1.5 +1.25 1.5 +1.333 2 +1.5 3 +1.5 1.5 +1.6 2 +1.667 2 +1 ...
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... Gain of 1 Configuration The AD8270 is designed to be stable for loop gains of 1.5 and greater. Because a typical voltage follower configuration has a loop gain may be unstable. Several stable configu- rations are listed in Table 8. DIFFERENTIAL OUTPUT The AD8270 can easily be configured for differential output. ...
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... AD8270 is operating in a gain of 0.5. –IN +IN 5V_REF 0.1µF –IN +IN To reduce the peaking, use a resistor between the AD8270 and the cable. Because cable capacitance and desired output response vary widely, this resistor is best determined empirically. A good starting point is 20 Ω. AD7688 ADC. The +12V –12V ...
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... Figure 52. 16-Lead Lead Frame Chip Scale Package [LFCSP_VQ × Body, Very Thin Quad (CP-16-10) Dimensions are shown in millimeters Package Description 16-Lead LFCSP_VQ 16-Lead LFCSP_VQ 16-Lead LFCSP_VQ Rev Page 0.60 MAX PIN 1 INDICATOR 2.50 EXPOSED 2.35 SQ PAD (BOTTOM VIEW) 2. 0.25 MIN 1.95 BSC Package Option CP-16-10 CP-16-10 CP-16-10 AD8270 ...
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... AD8270 NOTES ©2008 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D06979-0-1/08(0) Rev Page ...