AM417 AME | Alldatasheet

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RATIOMETRIC VOLTAGE TRANSMITTER AM417 analog microelectronics April 99 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

  • Supply Voltage 5V±±±±5% (Ratio Range)
  • Wide Operating Temperature Range: –40°C...+100°C
  • Ratiometrical Current Source for Transducer Excitation
  • Instrumentation Amplifier Input
  • Voltage Output Driver Open Collector: V OUT = 0.5–4.5V IOUT = +10mA
  • Adjustable Gain, Offset, and Output Voltage Range
  • Small Package Dimensions: SO8
  • Low Cost

APPLICATIONS

  • Industrial Process Control
  • Automotive Applications
  • Sensor Transmitter GENERAL DESCRIPTION The AM417 is a low cost ratiometrical voltage transmitter, designed for flexible bridge input signal conditioning. The IC contains a ra- tiometric current source for transducer excita- tion, a high accuracy instrumentation amplifier for differential input signals, and a voltage out- put driver. Gain, offset, and output voltage range are adjustable by external resistors. The voltage output stage is designed as an open col- lector stage. The output current is +10mA. A simple current limitation is possible by adding an external resistor. With its functional blocks and possibilities to adjust all important pa- rameters for sensor calibration, the small pack- age dimensions (SO8), and the low costs the AM417 is ideally suited for automotive sensor interface applications. DELIVERY
  • DIL8 packages (samples)
  • SOP8 packages
  • Dice on 5“ blue foil BLOCK DIAGRAM IA RB VOUT IN+ IN− AM417 IB 2 Output Stage GND VCC9R IBR OP VR VCC Figure 1

RATIOMETRIC VOLTAGE TRANSMITTER AM417 analog microelectronics April 99 ELECTRICAL SPECIFICATIONS Tamb = 25°C, VCC = 5V (unless otherwise noted) Parameter Symbol Conditions Min. Typ. Max. Unit Voltage Range (Ratio Range) VCC 4.75 5 5.25 V Maximum Supply Voltage VCCmax 6V Quiescent Current ICC RRB = 500Ω, IIB = 1mA 6.2 mA Temperature Specifications Operating Tamb –40 100 °C Storage Tst –55 125 °C Junction TJ 150 °C Thermal Resistance Θja DIL8 plastic package 110 °C/W Θja SO8 plastic package 180 °C/W Ratiometric Current Source – Transducer Internal Sense Voltage VRB ratiometric with VCC, VVCC = 5V 0.5 V Output Current Range IIB 0.50 1.25 mA Output Current IIB ratiometric with VCC, RRB = 500Ω, VVCC = 5V 0.98 1 1.02 mA Ratiometric Error RAT@IB V VCC = 5.25V, RAT@IB = 1.05 VRB (VVCC = 5V) – VRB (VVCC = 5.25V) ±1 mV IRB vs. Temperature d IRB/dTI IB = 1mA ±20 ppm/°C Output Voltage Range VIB IIB = 1.25mA 1.5 VCC–0.5 V Output Resistance RIB IIB = 1mA, RIB = ∆UIB/∆IIB, VVIB = 5V, IIB = 1mA 1.5 4.5 MΩ Power Supply Rejection Ratio ∆IIB ∆VCC = 4.75V – 5.25V, VVIB = 5V, IIB = 1mA 76 90 dB Instrumentation Amplifier Input Voltage Range VIN+;– 1.5 VCC–2 V Internal Gain GIA VIN– = 2V, ∆VIN = 200mV GIA = ∆VVIA/∆VIN 9.8 10.0 10.2 Common Mode Rejection Ratio CMRR 80 90 dB Power Supply Rejection Ratio PSRR 74 80 dB Offset Voltage VOS ±3 mV VOS vs. Temperature d VOS/dT ±10 µV/°C Input Bias Current IB VIN = 2V 25 75 nA Output Voltage Range VVIA 0 VCC–2 V Output Resistance ROUT 20 kΩ Nonlinearity ∆VIN = 200mV, ideal input 0.1 % FS Voltage Output Stage Adjustable Gain GOUT 21 1 Input Voltage Range VVR 0 VCC–2.5 V Power Supply Rejection Ratio PSSR –72 –90 dB Offset Voltage VOS ±3.0 mV VOS vs. Temperature d VOS/dT ∆VIN = 50mV ±15 µV/°C Input Current IIN ∆VIN = 50mV 20 75 nA Output Voltage Range VOUT with transistor BCW68H IOUT = 10mA (see figure 5) 0.5 4.5 V

RATIOMETRIC VOLTAGE TRANSMITTER AM417 analog microelectronics April 99 Parameter Symbol Conditions Min. Typ. Max. Unit Voltage Output Stage (cont.) Output Current IOUT with transistor BCW68H 12.5 mA Output Current Pin VOUT I VOUT pin VOUT 100 200 300 µA Current Limitation Threshold VTHRESH VTHRESH = VVCC – VVOUTmin, R2 = 27Ω, IOUT ≈ 14mA 120 150 180 mV Output Resistance ROUT virtual 0.1 0.85 Ω Linearity ideal input 0.01 %FS BOUNDARY CONDITIONS Parameter Symbol Conditions Min. Typ. Max. Unit Resistor Adjustment Current Source (Transducer) R1 400 1000 Ω Gain Resistor Sum R3 + R4 2.0 kΩ Capacitor Power Supply C1 100 nF Capacitor Frequency Compensation (Output Stage) C2 4.3 5.8 nF Capacitor Load (Output Stage) C3 1.0 10.0 nF Resistor Sense Current Limitation R2 05 0 Ω FUNCTIONAL DIAGRAM AMP IBR VS Ground VOUT GAIN = 20...110 (ratriometrical) Figure 2

RATIOMETRIC VOLTAGE TRANSMITTER AM417 analog microelectronics April 99 FUNCTIONAL DESCRIPTION The AM417 is an integrated low cost ratiometric voltage transmitter specially designed for bridge input signals in automotive applications. With its integrated, ratiometrical current source the AM417 is ideally suited for the signal conditioning of piezoresistive pressure transducers and allows an easy temperature compensation and span adjustment of a these kinds of sensors. The AM417 consists of 3 basic functional blocks: 1. A Ratiometrical Current Source for transducer excitation: The current IIB can be adjusted by the variation of the resistor R1 by the following relation: I V RIB VCC= 10 1 2. An Instrumentation Amplifier Input Stage with a fixed gain GIA = 10 for pre–amplifiing the bridge input signal. 3. An Open Collector Output Stage with the following functions:

  • Voltage Output: As output is used a voltage amplifier which has an external PNP–open col- lector stage T1 which is able to push a maximum current of IOUT = 5mA. The gain GOUT is ad- justable by the external resistors R3 and R4 between GOUT = 2...11: G R RROUT = + The gain G of the complete system becomes then G = GIA GOUT.
  • Current Limitation: A simple clamp stage for the output pin VOUT limits the voltage drop against VCC to ()VV V TOUT VCC BEmax .=− 15 1 . The maximum current can be set by adding a resistor in series to the Emitter of the transistor T1 at the output stage (see figure 4). For the maximum output current is valid: ()I VV T RROUT TRESH BE max = 370mV . If no current limitation is required, the Emitter of the transistor T1 has to be directly connected to VCC ( R2 = 0Ω). A proper thermic coupling of the Transistor T1 ( VBE–Drift: –2mV/°C typ.) and the AM417 reduces the resulting temperature drift of IOUT and increases the performance of the current limitation. Adjustment of Output Voltage Range The span of the output voltage could be adjusted by the gain GOUT of the output stage. The offset of the output voltage can be adjusted in the same way as the adjustment of the sensor offset using the resistors R O1 and RO2 (figure 4).

RATIOMETRIC VOLTAGE TRANSMITTER AM417 analog microelectronics April 99 PINOUT GND IB RB IN+ VCC VR IN VOUT Figure 3 DELIVERY The AM417 is available in:

  • 8 pin DIL packages (samples)
  • SO 8 packages
  • Dice on 5“ blue foil PACKAGE DIMENSIONS SOP8 PIN NAME DESIGNATION

1 GND IC Ground

2 IB Output Current Source

3 RB Adjustment Current Source

4 IN+ Input Positive

5 IN– Input Negative

6 VR Adjustment Gain Output Stage

7 VOUT Out Output Stage

8 VCC Supply Voltage

0°-10°≥ 0,3 1,27 ≤ 2,00 4,98 ± 0,1 1,45 ± 0,1 0,2 ± 0,1 6,2 ± 0,2 4,0 + 0,2 - 0,1 0,2 ± 0,05 Figure 4

RATIOMETRIC VOLTAGE TRANSMITTER AM417 analog microelectronics April 99 The current application shows the basic functions of the AM417. With the given values of the ex- ternal components (see List of External Components ) the following application features are ad- justed:

  • VIN = 100mV
  • G = GIA GOUT = 40
  • VOUT = 0.5 – 4.5V
  • IOUT = +10mA – 0.25mA
  • IBR = 1mA (ratiometrical supply current for the pressure transducer) LIST OF EXTERNAL COMPONENTS Symbol Description Value Unit T1 BCW68H, BC557C (or similar) low drop, high β at10mA PNP R1 IBR = 1 mA 500 Ω R2 IOUT = 10mA min (100°C) 15 Ω R3 Span (Gain adjustment) 500 Ω R4 VOUT = R3 / (R3 + R4) G 1.5 kΩ RS typical transducer resistor 3.0 (typ.) kΩ RTCS TC span compensation 10 – 120 kΩ RO1, RO2 Offset adjustment 0 – 500 Ω RTCO1, RTCO2 TC offset adjustment 0.1 – 10.0 MΩ C1 330 nF C2 ± 10% 4.7 nF C3 ± 10% 1.0 nF R1 R4 RO1RO2 RTCS RTCO1 VOUT VS Ground RTCO2 VIN RS RS RS RS IA AM417 Output Stage IBR OP VCC 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.