AM447 ETC | Alldatasheet

Document overview

  • Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
  • PDF pages: 6

Technical content

High Precision Instrumentation Amplifier AM447 analog microelectronics April 2000 Analog Microelectronics GmbH Phone: +49 (0)6131/91 073 – 0 1/6 An der Fahrt 13, D – 55124 Mainz Fax: +49 (0)6131/91 073 – 30 Rev. 2.1 Internet: www.analogmicro.de E–Mail: info@analogmicro .de

FEATURES

  • Very Low Offset Voltage: < 25µV
  • Low Input Bias Current: ≤≤≤≤ 5nA
  • High Input Sensitivity
  • High CMRR: > 90dB min
  • Wide Operating Temperature Range: –40°C...+140°C
  • Adjustable Rail–to–Rail Voltage Out-
  • Single Supply Device (ratiometric)
  • Integrated Source and Sink Capabil- ity: ±±±±2mA
  • Low Noise Behaviour

APPLICATIONS

  • Small Signal (Bridge) Amplifier Low Pressure Sensors Automotive Applications DMS Interface Interface for Ceramic Sensors
  • High Precision Amplifier Medical Instrumentation Data Acquisition GENERAL DESCRIPTION The AM447 is a high precision amplifier, de- signed for amplification of sensor bridge sig- nals up to 35mV full scale. The single supply circuit consists of a high precision instrumen- tation amplifier (IA) and an integrated ra- tiometric output stage. Input offset voltages less than ±25µV (±1µV/°C) are adjustable by only two externally trimmable resistors. The monitoring of the amplified signal is possible at the output of the IA and makes the adjust- ment easier. With the externally adjustable gain of the output stage, the AM447 can be used for different signal sources. The 2mA sink and source capability makes it ideal for high precision applications specially in the field of automotive sensors. DELIVERY
  • DIL16 packages (samples, small quantities)
  • SO16(n) packages
  • Dice on 5“ blue foil BLOCK DIAGRAM AM447 IA Output Stage 6 7 1412 5 8 OC2OC1 IN- IN+ VCC OUT GAIN GNDIAOUTVREFVREFINRSET VSET VCC 19k Figure 1

High Precision Instrumentation Amplifier AM447 analog microelectronics April 2000 ELECTRICAL SPECIFICATIONS VCC = 5V, Tamb = 25°C (unless otherwise noted) Parameter Symbol Conditions RM Min. Typ. Max. Unit Supply Voltage Range VCC yes 4.75 5 5.25 V Maximum Supply Voltage VCCmax 7V Quiescent Current ICC VIN = 0 2.2 3.3 4.6 mA Temperature Specifications Life Time LT 2500/10 h/a Operating Tamb T85% = 100°C for 85% of LT T15% = 120°C for 15% of LT Tmax = 140°C for t ≤ 50h –40 140 °C Storage Tst –55 125 °C Junction TJ 150 °C Thermal Resistance Θja DIL16 plastic package 70 °C/W Θja SO16 narrow plastic package 140 °C/W Instrumentation Amplifier Internal Gain GINT 100 102 104 Gain Drift(1) dGIINT /dT 30 ppm/°C Differential Input Voltage VIN VIN = VIN+ – VIN– 73 5 m V Common Mode Input Range CMIR 2.1 2.5 2.9 V Common Mode Rejection Ratio CMRR DC, RG = 0, VIN = 5mV 90 ≥ 105 dB Power Supply Rejection Ratio PSRR DC, RG = 0, VIN = 5mV 96 ≥ 105 dB Input Offset Voltage VOS RG = 0, compensated ± 25 µV VOS RG = 0, uncompensated ± 500 µV VOS vs. Temperature(1) dVOS /dTR G = 0, compensated ± 1 µV/°C dVOS /dTR G = 0, uncompensated ± 5 µV/°C Input Offset Current IOS yes ± 1 ± 5 nA IOS vs. Temperature d IOS /dT yes ± 5 ± 20 pA/°C Input Bias Current IB yes ± 15 ± 25 nA IB vs. Temperature d IB /dT yes ± 50 pA/°C Input-Referred Voltage Noise en 10Hz 25 60 nV/√Hz 0.1 ... 10Hz 1 µVPP Input-Referred Current Noise 10Hz 1.6 pA/√Hz 0.1 ... 10Hz 70 pA PP Output Voltage Range VIAOUT 0.15 VCC – 1.25 V Output Current IIAOUT Sourcing, VIAOUT = max. 50 µA Sinking, VIAOUT = min 20 µA Capacitive Load Stability CIAOUT 100 pF Nonlinearity End-point Method 20 40 ppm FS Reference Voltage Adjustable Voltage Range VREF yes 0.15 0.25 1.00 V Output Current IREF Sourcing 80 µA Sinking 80 µA Note: (1) No statistic measurements RM: Ratiometrical RG: Generator Source Resistance FS: Full Scale

High Precision Instrumentation Amplifier AM447 analog microelectronics April 2000 Parameter Symbol Conditions RM Min. Typ. Max. Unit Output Stage Adjustable Gain GADJ 1.2 1.65 4 Gain Drift d GADJ /dT 5 ppm/°C Common Mode Input Range CMIR 0.05 VCC – 1 V Common Mode Rejection Ratio CMRR DC 80 90 dB Power Supply Rejection Ratio PSRR 70 80 dB Input Offset Voltage VOS RG = 0 ± 0.6 ± 2.8 mV VOS vs. Temperature d VOS /dTR G = 0 ± 15 ± 25 µV/°C Input Bias Current IB yes –5 –10 –30 nA IB vs. Temperature d IB /dT yes 5 10 25 pA/°C Output Voltage Range VOUT,min Sinking, IOUT = 2mA 100 200 mV VOUT,max Sourcing, IOUT = 2mA VCC – 0.2 V Output Resistance ROUT 1 Ω Capacitive Load Stability CLOAD 04 7 n F Slew Rate SR C LOAD= 5nF yes 0.027 V/µs Sink Capability ISink VOUT = 2.5V, GADJ = 1 2 mA Source Capability ISource VOUT = 2.5V, GADJ = 1 2 mA ESD: This integrated circuit can be damaged by ESD. Analog Microelectronics recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. BOUNDARY CONDITIONS Parameter Symbol Conditions Min. Typ. Max. Unit Offset Compensation Resistor (IA) 1 1) ROC1 27 33 kΩ Offset Compensation Resistor (IA) 2 1) ROC2 27 33 kΩ Gain Resistor 1 RG1 67.3 68.7 kΩ Gain Resistor 2 RG2 14 210 kΩ Offset Compensation Resistor (Bridge) 1 RO1 19 kΩ Offset Compensation Resistor (Bridge) 2 RO2 1 kΩ Set Resistor 2) RSET 75.0 76.8 78.7 kΩ Sensor Bridge Resistor 3) RBRIDGE 71 3 kΩ Differential Input Voltage VIN VCC = 5V 7 35 mV Notes: 1) The offset adjustment is described in the Functional Description. An offset compensation over temperature can only be achieved by choosing the resistors ROC1 and ROC2 with the same temperature coefficient and a very close placement of them in the circuit. 2) A good matching of the resistor RSET with the bridge resistors is forced. 3) The symmetry of the two resistor half bridges has to be better than 2%.

High Precision Instrumentation Amplifier AM447 analog microelectronics April 2000 FUNCTIONAL DESCRIPTION The IC AM447 is an integrated high precision amplifier for low bridge output signals. Basically the AM447 is composed of 2 functional sections as shown in Figure 1: 1. A high accuracy instrumentation amplifier (IA) allows amplification with a high signal-to-noise ratio. The two offset compensation resistors ROC1 and ROC2 offer the possibility to make the input offset voltage of the instrumentation amplifier to nearly zero. But offset compensation over tem- perature is only given if the resistors R OC1 and ROC2 have the same temperature coefficients. Fur- thermore, these resistors have to be placed together very close. It is also necessary to use similar metals for the connection of the sensor bridge and the AM447 to avoid thermocouple effects. The internal gain of the IA is fixed to the value 102 = INTG . The output voltage VIAOUT (pin 10) of the IA is given by the following equation: ()VG V V VIAOUT INT IN IN VREF=⋅− + +− 2. An output stage de–couples the IA and thus improves the performance of the AM447. The gain factor G is fixed by the two external resistors RG1 and RG2. The gain factor of the output stage is defined by G R RADJ G G =+1 2 The output signal VOUT (pin 10) can be calculated with () () { rs transducekalibrated for adjustmentOffset adjustmentSpan VREFININADJINTVREFININOUT VVVGGVVVGV +−⋅=+−= −+−+ 44443444421 The AM447 is suited for two types of transducers. The IC is designed for usage with non- compensated and non-calibrated sensors using resistors R1 and R2 for offset calibration as well as for sensor systems with calibrated transducers. The remaining offset of the transducers can be cali- brated by variation of V VREF. The adjustment of the offset is then: CC OO O VREF VRR RV The entire sensor systems realised with the different types of AM447 and only a few external com- ponents are shown in Figures 2 and 3. Offset calibration of the instrumentation amplifier The offset compensation has to be handled with care because the entire system performance de- pends on it. Please note, that this offset adjustment doesn't include the bridge offset. The offset compensation has to be done in the following order:

  • T =°25 C and VCC = 5V
  • VVVIN IN REF+−=== 25.V
  • The voltage between VIAOUT (pin 12) and VREF (pin 6) has to be adjusted to zero Volt.
  • VIAOUT is increased by increasing ROC1 and is decreased by increasing ROC2.

High Precision Instrumentation Amplifier AM447 analog microelectronics April 2000 PINOUT 8 9 OC1 OC2 IN RSET VREF GND VREFIN I.C. VCC N.C. IAOUT GAIN OUT VSET I.C. IN+ Figure 4 DELIVERY The AM447 is available in version:

  • 16 pin DIL packages (samples)
  • SO 16 (n) packages
  • Dice on 5“ blue foil PINOUT PIN NAME DESIGNATION

1 OC1 Offset Compensation Resistor 1

2 OC2 Offset Compensation Resistor 2

3 IN– Inverting Input (IA)

4 IN+ Non–inverting Input (IA)

5 RSET Set Resistor

6 VREF Reference Voltage

7 GND Ground

8 VREFIN Reference Voltage Input

9 VSET Choice of Application

10 OUT Output

11 GAIN Gain Adjustment

12 IAOUT Output (IA)

13 N.C. Not Connected

14 VCC Supply Voltage

15 I.C. Internally Connected 16 I.C. Internally Connected 0°-10°≥ 0,3 6,2 ± 0,2 4,0 + 0,2 - 0,1 0,2 ± 0,05 1,27 ≤ 2,00 10,06 ± 0,1 1,45 ± 0,1 0,2 ± 0,1 Figure 5 The information provided herein is believed to be reliable; however, Analog Microelectronics assumes no responsibility for inaccuracies or omissions. Analog Microelectronics assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user's own risk. Prices and specifications are subject to change without notice. No patent rights or licences to any of the circuits described herein are implied or granted to any third party. Analog Microelectronics does not authorise or warrant any Analog Microelectronics product use in life support devices and/or systems.