AM460

AM460 ANALOGMICRO | Alldatasheet

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Industrial Converter and Protector IC AM460 analog microelectronics April 2003 Analog Microelectronics GmbH Phone: +49 (0)6131/91 073 – 0 1/18 An der Fahrt 13, D – 55124 Mainz Fax: +49 (0)6131/91 073 – 30 Rev. 1.1 Internet: http://www. analogmicro.de E–mail: info@analogmicro .de PRINCIPLE FUNCTION Amplification and conversion of voltage signals referenced to ground Integrated protection for IC and external components Integrated, adjustable current/voltage sources for external components VREF = 5/10V AM460 VS = 6...35V VOUT = 0...5/10V IS = e.g. 1.5mA Single-ended input signal IOUT = 0/4...20mA TYPICAL APPLICATIONS

• Peripheral processor IC (see Figure 12 on page 17)
• Industrial protector and output IC for microprocessors (Frame ASIC concept [ 1])
• Impedance converter
• Adjustable voltage and current source (supply unit)
• Voltage regulator with additional functions

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 Analog Microelectronics GmbH Phone: +49 (0)6131/91 073 – 0 3/18 An der Fahrt 13, D – 55124 Mainz Fax: +49 (0)6131/91 073 – 30 Rev. 1.1 Internet: http://www. analogmicro.de E–mail: info@analogmicro .de

FEATURES

• Supply voltage: 6...35V
• Wide working temperature range: –40°C...+85°C
• Adjustable integrated reference voltage source: 4.5 to 10V
• Additional voltage/current source
• Operational amplifier with integrated driver stage
• Adjustable amplification
• Analogue parallel voltage (0...5/10V) and current output (0/4...20mA)
• Protection against reverse polarity and short-circuiting
• Output current limit
• Low-cost device: replaces a number of discrete elements
• 2- and 3-wire operation GENERAL DESCRIPTION AM460 is a universal converter and amplifier IC with a number of additional functions. The IC basi- cally consists of an amplifier, whose gain can be set externally, and parallel output stages which can con- dition signals referenced to ground in industrial voltage and current signals. An additional reference voltage source for the supply of external components is also included in the device. A further operational amplifier can be connected up as a current source, voltage reference or comparator. One of the main features of the IC is its integrated protective circuitry. The device is protected against reverse polarity, short-circuiting and has a built-in output current limit. Amplifier IC AM460 enables industrial standard voltage (e.g. 0–5/10V) and cur- rent loop (e.g. 0/ 4–20mA) signals to be pr oduced relatively easily. BLOCK DIAGRAM VREF VOUT SET OUTAD INDAI GND VSET INDAVINN INP IOUT RS+ VCC CVREF CVSET VBG 7 14 V I 13 15 V oltage Reference OP1 AM460 OP3 OP2 RS-9 Figure 1: Block diagram of AM460

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 ELECTRICAL SPECIFICATIONS Tamb = 25°C, VCC = 24V, VREF = 5V, IREF = 1mA (unless otherwise stated), currents flowing into the IC are negative Parameter Symbol Conditions Min. Typ. Max. Unit Supply Voltage Range VCC 63 5 V Quiescent Current ICC Tamb = – 40...+85°C, IREF = 0mA 1.5 mA Temperature Specifications Operating Tamb –40 85 °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 Voltage Reference Voltage VREF VSET not connected 4.75 5.00 5.25 V VREF10 VSET = GND, VCC ≥ 11V 9.5 10.0 10.5 V Trim Range VREFADJ 4.5 VREF10 V Current IREF* 0 10.0 mA VREF vs. Temperature d VREF/dTT amb = – 40...+85°C ±90 ±140 ppm/°C Line Regulation d VREF/dVV CC = 6V...35V 30 80 ppm/V dVREF/dV VCC = 6V...35V, IREF ≈ 5mA 60 150 ppm/V Load Regulation d VREF/dI 0.05 0.10 %/mA dVREF/dI IREF ≈ 5mA 0.06 0.15 %/mA Load Capacitance CL 1.9 2.2 5.0 µF Current/Voltage Source OP2 Internal Reference VBG 1.20 1.27 1.35 V VBG vs. Temperature d VBG/dTT amb = – 40...+85°C ±60 ±140 ppm/°C Current Source: ICV = VBG/RSET, from Figure 5 Adjustable Current Range ICV*0 1 0 m A Output Voltage VCV VCC < 19V VBG VCC – 4 V VCV VCC ≥ 19V VBG 15 V Voltage Source: VCV = VBG (1 + R7 / R6), from Figure 6 Adjustable Voltage Range VCV VCC < 19V 0.4 VCC – 4 V VCV VCC ≥ 19V 0.4 15 V Output Current ICV*S o u r c e 1 0 m A ICV Sink –100 µA Load Capacitance CL Source mode 0 1 10 nF Operational Amplifier Gain Stage (OP1) Adjustable Gain GGAIN 1 Input Range IR V CC < 10V 0 VCC – 5 V IR VCC ≥ 10V 05 V Power Supply Rejection Ratio PSRR 80 90 dB Offset Voltage VOS ±0.5 ±2m V VOS vs. Temperature d VOS/dT ±3 ±7µ V / ° C

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 Parameter Symbol Conditions Min. Typ. Max. Unit Operational Amplifier Gain Stage (OP1) (cont.) Input Bias Current IB 10 25 nA IB vs. Temperature d IB/dT 72 0 p A / ° C Output Voltage Limit VLIM VREF V Output Voltage Range VOUTAD VCC < 10V 0 VCC – 5 V VOUTAD VCC ≥ 10V 0 VREF V Load Capacitance CL 250 pF Operational Amplifier Output Stage (OP3) Internal Gain GOP 2.15 2.20 2.25 Input Range IR V CC < 11V 0 VCC – 5 V IR VCC ≥ 11V 06 V Power Supply Rejection Ratio PSRR 80 90 dB Offset Voltage VOS ±0.5 ±2m V VOS vs. Temperature d VOS/dT ±3 ±7µ V / ° C Input Bias Current IB 10 25 nA IB vs. Temperature d IB/dT 72 0 p A / ° C Output Voltage Range VOUT VCC < 19V 0 VCC – 5 V VOUT VCC ≥ 19V 01 4 V Output Current Limitation ILIM VOUT ≥ 10V 57 1 0 m A Output Current IOUT 0 ILIM mA Load Resistance RL 2 kΩ Load Capacitance CL 500 nF V/I Converter Internal Gain GVI 0.125 Trim Range Adjustable by R0 0.75 1.00 1.25 Voltage Range at R0 FS VR0FS 350 750 mV Offset Voltage VOS βF ≥ 100 ±2 ±4m V VOS vs. Temperature d VOS/dT βF ≥ 100 ±7 ±14 µV/°C Input Resistance RIN 120 160 kΩ RIN vs. Temperature d RIN/dT 0.2 0.3 kΩ/°C Output Offset Current IOUTOS 3-wire operation –25 –35 µA IOUTOS vs. Temperature d IOUTOS/dT 3-wire operation 16 26 nA/°C Output Offset Current IOUTOS 2-wire operation 9.5 14 µA IOUTOS vs. Temperature d IOUTOS/dT 2-wire operation 6 8 nA/°C Output Control Current IOUTC 2-wire operation, VR0/100mV 6 8 µA IOUTC vs. Temperature d IOUTC/dT 2-wire operation –10 –15 nA/°C Output Voltage Range VOUT VOUT = RL IOUT, VCC < 18V 0 VCC – 6 V VOUT VOUT = RL IOUT, VCC ≥ 18V 01 2 V Output Current Range FS IOUTFS IOUT = VR0/R0, 3-wire operation 20 mA Output Resistance ROUT 0.5 1.0 MΩ Load Capacitance CL 0 500 nF

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 Parameter Symbol Conditions Min. Typ. Max. Unit SET Stage Internal Gain GSET 0.5 Input Voltage VSET 01 . 1 5 V Offset Voltage VOS ±0.5 ±1.5 mV VOS vs. Temperature d VOS/dT ±1.6 ±5µ V / ° C Input Bias Current IB 82 0 n A IB vs. Temperature d IB/dT 71 8 p A / ° C Protection Functions Voltage Limitation at R0 VLIMR0 VR0 = VINDAI GVI, SET = GND 580 635 690 mV VLIMR0 VINDAI = 0, VR0 = GSET VSET 580 635 690 mV Protection against reverse polarity Ground vs. VS vs. VOUT 35 V Ground vs. VS vs. IOUT 35 V Current with reverse polarity Ground = 35V, VS = IOUT = 0 4.5 mA System Parameters Nonlinearity Ideal input 0.05 0.15 %FS * In 2-wire operation a maximum current of IOUTmin – ICC is valid BOUNDARY CONDITIONS Parameter Symbol Conditions Min. Typ. Max. Unit Sense Resistor R0 IOUTFS = 2 0 m A 1 72 73 8 Ω R0 c = 20mA/IOUTFS c ⋅ 17 c ⋅ 27 c ⋅ 38 Ω Stabilisation Resistor R5 IOUTFS = 2 0 m A 3 54 04 5 Ω R5 c = 20mA/IOUTFS c ⋅ 35 c ⋅ 40 c ⋅ 45 Ω Load Resistor RL Only for 3-wire operation 0 600 Ω Sum Gain Resistors R1 + R2 20 200 kΩ Sum Offset Resistors R3 + R4 20 200 kΩ VREF Capacitor C1 Ceramic 1.9 2.2 5.0 µF Output Capacitor C2 Only for 2-wire operation 90 100 250 nF D1 Breakdown Voltage VBR 35 50 V T1 Forward Current Gain βF BCX54/55/56, for example 50 150 DETAILED DESCRIPTION OF FUNCTIONS AM460 is a modular, universal converte r and protector IC which has been specially developed for the condi- tioning of voltage signals referenced to ground. It has been conceived for both 2- and 3-wire operation 1 in in- dustrial applications (cf. application on page 8). The functions of AM460 are depict ed in the block diagram (Figure 2) which also illustrates how few external com ponents are required for the operation of this particular device. Electrical specifications for the external components are given on page 6. 1The principle of AM460 is such that only the current output can be used in 2-wire operation.

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 AM460 consist of several modular function blocks (opera tional amplifiers, voltage-to-current converters and references) which depending on external configurations can either be switched together or operated separately (see the basic circuitry in Figure 2): 1. Operational amplifier stage OP1 enables a positive voltage signal to be amplified. OP1 gain GGAIN can be set via external resistors R1 and R2. Protective circuitry against overvoltage is integrated into the chip, limiting the voltage to the set value of the reference voltage. Output voltage VOUTAD at pin OUTAD is calculated as: GAININPOUTAD GVV ⋅= with 11 R RGGAIN += (1) where VINP is the voltage at OP1 input pin INP. 2. Using the current-limited operational amplifier stage OP3 with its integrated protection against reverse po- larity an industrial voltage signal ( VOUT) can be realised. The internal amplification of OP3 is set to a fixed value of GOP = 2.2. The output is configured as a driver so that OP3 is particularly suitable as an output stage. For OP3 output voltage VOUT at pin VOUT of the IC the following applies: INDAVOPOUT VGV ⋅= (2) with VINDAV the voltage at pin INDAV (OP3 input). 3. The voltage-to-current converter (V/I converter) prov ides a voltage-controlled current signal at IC output IOUT (pin 8) which activates an external transistor T1; this in turn supplies the actual output current IOUT. To VBG Ground VS IOUT VOUT VINP VSET VOUTAD VCVREF VCVSET VBG OP1 AM460 OP2 VREF 13 15 V oltage Reference 1 16 VINDAI VINDAV 71 4 V I OP3 Figure 2: Block diagram of AM460 with external components (3-wire circuit for current output)

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 reduce power dissipation the tr ansistor is an external component and protected against reverse polarity by an additional diode D1. Via pin SET an offset current ISET can be set at output IOUT (with the help of the inter- nal voltage reference and an external voltage divider as shown in Figure 2, for example). External resistor R0 permits the output current to be fine ly adjusted with parallel operation of current and the voltage output. For the output current provided by T1 the following ratio applies: SET INDAI OUT IR VI += 08 with 02R VI SET SET = (3) with VINDAI the voltage at INDAI and VSET the voltage at pin SET (V/I converter inputs, Figure 2)2. 4. The AM460 reference voltage source enables voltage to be supplied to external components (such as sen- sors, microprocessors, etc.). The reference voltage value VREF can be set via pin 13 VSET. If pin VSET is not connected, VREF = 5V; if VSET is switched to ground, VREF = 10V. Values between these can be set if two external resistors are used (inserted between pin VREF and pin VSET and between pin VSET and GND). External (ceramic) capacitor C1 at pin VREF stabilises the reference voltage. It must be connected even if the voltage reference is not in use. 5. The additional operational amplifier stage OP2 can be used as a current or voltage source to supply external components. OP2's positive input is connected internally to voltage VBG so that the output current or output voltage can be set across a wide range using one or two external resistors. OPERATING AM460 General information on 2- and 3-wire applications and the use of the current output In 3-wire operation (cf. Figure 3 right and Figure 7) the ground of the IC (pin GND) is connected up to the ex- ternal mass of the system Ground. The system's supply voltage VS is connected to pin VCC and pin VCC to pin RS+. In 2-wire operation (cf. Figure 3 left and Figure 7) system supply voltage VS is connected to pin RS+ and pin VCC to RS-. The ground of the IC (pin GND) is connected to the node between resistor R5 and load resistor RL (current output IOUT). IC ground (GND) is not the same as system ground (Ground)!! The output signal is picked up via load resistor RL which connects current output IOUT to the system ground. 2 The construction of the V/I converter is such that output current IOUT is largely independent of the current amplification βF of external transistor T1. Production-specific variations in the current amp lification of the transistors used are compensated for internally by the V/I converter. RL VS 2-wire system signal source and conditioning IC GND Ground ≠ VCC ≠ VS Ground RL 3-wire system signal source and conditioning IC GND Ground = VCC = VS Ground GND = GND VCC IOUT IOUT VVCC S = Figure 3: Difference between 2- and 3-wire operation

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 In 2-wire operation the IC ground is "virtual" (floating), as with a constant load resistance the supply voltage of the device VCC changes according to the current. As a rule, the following equation applies to 2-wire operation: () LINOUTSCC RVIVV −= (4) The reason for this is that in 2-wire operation the IC is connected in series to the actual load resistor RL. This is illustrated in Figure 3. In 3-wire operation VCC = VS, as the IC ground is connected to the ground of the system. Setting the voltage gain using the voltage output Using amplifier stages OP1 and OP3 for signal conditioning the overall gain can be set by selecting suitable ex- ternal resistors R1 and R2. The transfer function for the output voltage is calculated by multiplying Equations 1 and 2 as follows: OPGAININPOUT GGVV ⋅⋅= (5) with GGAIN = 1 + R1/R2 and GOP = 2.2. Setting the output current range using the current output When using amplification stage OP1 together with the V/ I converter for signal conditioning the offset of the output current should first be compensated for by suitable selection of resistors R3 and R4. To this end the OP1 input must be connected to ground ( VINP = 0). With the short circuit at the input and by connecting up V/I con- verter pin VSET as shown in Figure 2 the values of the output current according to Equation 3 are as follows: 020 RR R R VIVI REF SETINDAIOUT +⋅=== (6) and thus for the ratio of the resistors R3/R4: 12 04 3 −= SET REF IR V R R (7) The output current area is set in conjunction with the selection of external resistors R1 and R2 (or fine adjustment with R0 ). With Equations 1 and 3 the following is calculated for output current IOUT : SET GAIN INPOUT IR GVI += 08 with 11 R RGGAIN += (8) Selecting the supply voltage System supply voltage VS needed to operate AM460 is dependent on the selected mode of operation.

• When using voltage output pin VOUT the minimum VS needed for operation is determined by the maximum output voltage VOUTmax required by the application. This is expressed as follows: V5max +≥ OUTS VV (9)

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 R6 and R7: 6.116.21 6 =−≈−= BG CVREF V V R R The following example values are produced for the resistors: R7 = 10kΩ R 6 = 16kΩ OPERATING AM460: IMPORTANT POINTS TO NOTE 1. When using AM460 it is impera tive that external capacitor C1 (a top-grade ceramic capacitor) is always connected (cf. Figure 2). Care must be taken that th e value of the capacitor, al so within the temperature range, does not exceed the range of values given in the boundary conditions on page 6. In 2-wire operation ceramic capacitor C 2 must also be used (cf. Figure 8) 2. In a 2-wire setup the power consumption of the entir e system (AM460 plus all external components, in- cluding the configuration resistors) must not exceed the sum of IOUTmin (usually 4mA). 3. All AM460 function blocks not require d by the application must be connected to a defined (and allowed) potential. 4. With operation of the voltage output the load resistance at pin VOUT must be at least 2kΩ. 5. When operating the current output a maximum load resistance of 600Ω is permitted. 6. The values of external resistors R0, R1, R2, R3, R4 and R5 must be selected within the permissible range given in the boundary conditions on page 6.

APPLICATIONS

Typical 3-wire application with an input signal referenced to ground Figure 7 shows a 3-wire application in which AM460 amplifies and converts a positive voltage signal refer- enced to ground. The unused blocks (e.g. OP2) have been set to defined operating point s. Alternatively, these function groups can also be used here (e.g. to supply external components). In this particular application, using Equations 1 and 2 output voltage VOUT is calculated as: INPVOUT VGV = with 2.21 1 ⋅  +== R RGGG OPGAINV (14) For output current IOUT the following applies according to Equation 3: SET I INPOUT IR GVI +⋅= 08 with 11 R RGG GAINI +== and 0=SETI

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 Example 3: To obtain a signal of VINP = 0...1V at the OP1 input the external com ponents are to be dimensioned in such a 0...10V. Using Equation 14 the output voltage is defined as follows: 2.21 1 ⋅  +⋅= R RVV INPOUT ⇒ 55.31V12.2 V1012.22 INP OUT V V R R i.e. 55.41 1 =+= R RGGAIN The following then applies to the output current: 00 88 R GVIR GVI GAIN INPSET I INPOUT ⋅=+⋅= ⇒ Ω≈⋅=⋅= 44.28mA208 55.4V18 OUT GAIN INP I GVR Observing the boundary conditions, the following values are obtained for the external components: R0 ≈ 28.44Ω R1 ≈ 35.5kΩ R 2 = 10kΩ R5 = 39Ω RL = 0...600Ω C1 = 2.2µF Ground RL Single-ended input voltage Connections setting unused function blocks to a defined operating point ISET = 0 VBG AM460 OP3 OP2 OP1 V oltage Reference 71 46 13 15 16 V I 3-wire connection VINP VS VOUT IOUT Figure 7: Typical application for input signals referenced to ground

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 Typical 2-wire application with an input signal referenced to ground In 2-wire operation (cf. Figure 8) system supply voltage VS is connected up to pin RS+ and pin VCC to pin RS-. The ground of the IC (pin GND) is connected to the node between resistor R5 and load resistor RL (current output IOUT). IC ground (GND) is not the same as system ground (Ground)!! The output signal is picked up via load re- sistor RL which connects current output IOUT to the system ground. For output current IOUT the following applies according to Equation 3: SET I INPOUT IR GVI +⋅= 08 with 11 R RGG GAINI +== and 02 RR R R VI REF SET +⋅= Example 4: To obtain a signal of VINP = 0...1V at the OP1 input the external com ponents are to be dimensioned in such a way that the output current has a range of 4...20mA. mA488 00 +⋅=+⋅= R GVIR GVI GAIN INPSET I INPOUT With R0 = 27Ω Equation 7 produces the following: 15.221mA4272 V512 04 SET REF IR V R R and thus the following value for the gain to be set: Ground RL Single-ended input voltage AM460 OP3 OP2 OP1 R3C1 V oltage Reference 71 46 13 15 16 IC ground: GND System ground: Ground} Different potentials! GND 2-wire connection V I VINP VS IOUT VBG Connections setting unused function blocks to a defined operating point Figure 8: Typical 2-wire application for input signals referenced to ground

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 456.3V1 mA162788 max 0 =⋅Ω⋅=−= INP SETOUT GAIN V IIRG ⇒ 456.21456.3 1 =−=R R Observing the boundary conditions, the following values are obtained for the external components: R1 ≈ 24.56kΩ R 2 = 10kΩ R3 ≈ 44.3kΩ R4 = 2kΩ R0 = 27Ω R5 = 39Ω RL = 0...600Ω C1 = 2.2µF C2 = 100nF

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 BLOCK DIAGRAM AND PINOUT 8 9 CVREF CVSET INP OUTAD INDAI INDAV IOUT SET GND VSET VOUT RS+ VCC RS− VREF INN Figure 10: Pinout VREF VOUT SET OUTAD INDAI GND VSET INDAVINN INP IOUT RS+ VCC CVREF CVSET VBG 7 14 V I 13 15 V oltage Reference OP1 AM460 OP3 OP2 RS-9 Figure 9: Block diagram of AM460 PIN NAME EXPLANATION

1 CVREF Current/Voltage reference

2 CVSET Current/Voltage reference set

3 INP Positive input

4 INN Negative input

5 OUTAD System amplification output

6 INDAI Current output stage input

7 INDAV Voltage output stage input

8 IOUT Current output

9 RS- Sensing resistor -

10 VCC Supply voltage

11 RS+ Sensing resistor +

12 VOUT Voltage output

13 VSET Reference voltage source set

14 GND IC ground

15 VREF Reference voltage source output

16 SET Output offset current set

Table 1: AM460 pinout

Industrial Converter and Protector IC AM460 analog microelectronics April 2003 DELIVERY The AM460 converter and protector IC is available as the following packages:

• DIP16
• SO16(n) (maximum power dissipation PD = 300mW)
• Dice on 5" blue foil FURTHER READING [1] The Frame ASIC concept: http://www.Frame-ASIC.de/ [2] The Analog Microel ectronics GmbH website: http://www.analogmicro.de/ NOTES Analog Microelectronics reserves the right to make amendments to any dimensions, technical data or other information herein without further notice.