Datasheet AD8224 (Analog Devices)

Precision, Dual-Channel, JFET Input, Rail-to-Rail Instrumentation Amplifier Data Sheet AD8224 FEATURES FUNCTIONAL BLOCK DIAGRAM Two channels in a small 4 mm × 4 mm LFCSP S T1 T2 S Custom LFCSP package with hidden paddle +V OU OU –V Permits routing and vias underneath package 16 15 14 13 Allows full bias current performance AD8224 Low input currents –IN1 1 12 –IN2 10 pA maximum input bias current (B grade) R 2 11 G1 RG2 0.6 pA maximum input offset current (B grade) R 3 10 G1 RG2 High CMRR +IN1 4 9 +IN2 100 dB CMRR (minimum), G = 10 (B grade) 90 dB CMRR (minimum) to 10 kHz, G = 10 (B grade) 5 6 7 8 S 1 2 S
001
Excellent ac specifications and low power F F +V –V RE RE
06286-
1.5 MHz bandwidth (G = 1)
Figure 1.
14 nV/√Hz input noise (1 kHz) Slew rate: 2 V/µs Table 1. In Amps and Difference Amplifiers by Category 750 µA quiescent current per amplifier High Low High Mil Low Digital Versatility Perform Cost Voltage Grade Power Gain Rail-to-rail output
AD82201 AD85531 AD628 AD620 AD6271 AD82311
Input voltage range to below negative supply rail
AD8221 AD6231 AD629 AD621 AD8250
4 kV ESD protection
AD8222 AD524 AD8251
4.5 V to 36 V single supply
AD526 AD85551
±2.25 V to ±18 V dual supply
AD624 AD85561
Gain set with single resistor (G = 1 to 1000)
AD85571
APPLICATIONS
1 Rail-to-rail output.
Medical instrumentation Precision data acquisition Transducer interfaces Differential drives for high resolution input ADCs Remote sensors GENERAL DESCRIPTION
The AD8224 is the first single-supply, JFET input instrumentation to alleviate this problem, the AD8224 can operate on a ±18 V amplifier available in the space-saving 16-lead, 4 mm × 4 mm dual supply, as well as on a single +5 V supply. The device’s rail- LFCSP. It requires the same board area as a typical single to-rail output stage maximizes dynamic range on the low voltage instrumentation amplifier yet doubles the channel density supplies common in portable applications. Its ability to run on a and offers a lower cost per channel without compromising single 5 V supply eliminates the need for higher voltage, dual performance. supplies. The AD8224 draws 750 µA of quiescent current per amplifier, making it ideal for battery powered devices. Designed to meet the needs of high performance, portable instrumentation, the AD8224 has a minimum common-mode In addition, the AD8224 can be configured as a single-channel, rejection ratio (CMRR) of 86 dB at dc and a minimum CMRR differential output, instrumentation amplifier. Differential of 80 dB at 10 kHz for G = 1. Maximum input bias current is 10 pA outputs provide high noise immunity, which can be useful when and typical y remains below 300 pA over the entire industrial the output signal must travel through a noisy environment, such temperature range. Despite the JFET inputs, the AD8224 as with remote sensors. The configuration can also be used to typical y has a noise corner of only 10 Hz. drive differential input ADCs. For a single-channel version, use the AD8220. With the proliferation of mixed-signal processing, the number of power supplies required in each system has grown. Designed
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Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE Maximum Power Dissipation ESD CAUTION PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION GAIN SELECTION REFERENCE TERMINAL LAYOUT Package Considerations Hidden Paddle Package Exposed Pad Package Common-Mode Rejection over Frequency Reference Power Supplies SOLDER WASH INPUT BIAS CURRENT RETURN PATH INPUT PROTECTION RF INTERFERENCE COMMON-MODE INPUT VOLTAGE RANGE APPLICATIONS INFORMATION DRIVING AN ADC DIFFERENTIAL OUTPUT Setting the Common-Mode Voltage 2-Channel Differential Output Using a Dual Op Amp DRIVING A DIFFERENTIAL INPUT ADC First Antialiasing Filter Second Antialiasing Filter Reference DRIVING CABLING OUTLINE DIMENSIONS ORDERING GUIDE