Precision Instrumentation Amplifier with Signal Processing Amplifiers AD8295
The AD8295 contains all the components necessary for a precision instrumentation amplifier front end in one small 4 mm × 4 mm package. It contains a high perbbbbance instrumentation amplifier, two general-purpose operational amplifiers, and two precisely matched 10 kΩ resistors.
The AD8295 is designed to make PCB routing easy and efficient. The AD8295 components are arranged in a logical way so that typical application circuits have short routes and few vias. Unlike most chip scale packages, the AD8295 does not have an exposed bbbbl pad on the back of the part, which frees additional space for routing and vias. The AD8295 comes in a 4 mm × 4 mm LFCSP that requires half the board space of an 8-pin SOIC package.
The AD8295 includes a high perbbbbance, programmable gain instrumentation amplifier. Gain is set from 1 to 1000 with a single resistor. The low noise and excellent common-mode rejection of the AD8295 enable the part to easily detect small signals even in the presence of large common-mode interference. For a similar instrumentation amplifier without the associated signal conditioning circuitry, see the AD8221 or AD8222 data sheet.
The AD8295 operates on both single and dual supplies and is well suited for applications where ±10 V bbbbb voltages are encountered. Perbbbbance is specified over the entire industrial temperature range of −40°C to +85°C for all grades. The AD8295 is operational from −40°C to +125°C; see the Typical Perbbbbance Characteristics section for expected operation up to 125°C.
AD8295主要特性:
Saves board space
Includes precision in-amp, 2 op amps, and 2 matched resistors
4 mm × 4 mm LFCSP
No heat slug for more routing room
Differential output fully specified
In-amp specifications
Gain set with 1 external resistor (gain range: 1 to 1000)
8 nV/√Hz @ 1 kHz, maximum bbbbb voltage noise
90 dB minimum CMRR (G = 1)
0.8 nA maximum bbbbb bias current
1.2 MHz, −3 dB bandwidth (G = 1)
2 V/μs slew rate
Wide power supply range: ±2.3 V to ±18 V
1 ppm/°C, 0.03% resistor matching
AD8295应用:
Industrial process controls
Wheatstone bridges
Precision data acquisition systems
Medical instrumentation
Strain gages
Transducer interfaces
Differential output
图1.AD8295功能方框图
图2.AD8295电源去耦电路及REF与输出对地连接图
图3.AD8295对RFI抑制电路图
图4.AD8295差分输出最少元件连接图
图5.AD8295带缓冲基准的单电源连接图
图6.采用AD8295的2极点Sallen-Key滤波器电路
图7.AD8295AC耦合连接图
图8.AD8295驱动差分ADC电路图