Industrial Converter and Protector IC AM460 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 VS = 6...35V Single-ended input signal IOUT = 0/4...20mA AM460 VOUT = 0...5/10V e.g. 0...5V, 0...1V VREF = 5/10V IS = e.g. 1.5mA 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 analog microelectronics Analog Microelectronics GmbH An der Fahrt 13, D – 55124 Mainz Internet: http://www.analogmicro.de Phone: +49 (0)6131/91 073 – 0 Fax: +49 (0)6131/91 073 – 30 E–mail: [email protected] April 2003 1/18 Rev. 1.1 Industrial Converter and Protector IC AM460 TABLE OF CONTENTS Features General Description Block Diagram Electrical Specifications Boundary Conditions Detailed Description of Functions Operating AM460 General information on 2- and 3-wire applications and the use of the current output Setting the voltage gain using the voltage output Setting the output current range using the current output Selecting the supply voltage Connecting OP2 as a current source Connecting OP2 as a voltage reference Operating AM460: Important Points to Note Applications Typical 3-wire application with an input signal referenced to ground Typical 2-wire application with an input signal referenced to ground Block Diagram and Pinout Examples of Possible Applications Delivery Further Reading 3 3 3 4 6 6 8 8 9 9 9 10 11 12 12 12 14 16 17 18 18 TABLE OF FIGURES Table 1: AM460 pinout 16 Figure 1: Block diagram of AM460 Figure 2: Block diagram of AM460 with external components (3-wire circuit for current output) Figure 3: Difference between 2- and 3-wire operation Figure 4: Working range in conjunction with the load resistor Figure 5: Connecting up a constant current source Figure 6: Connecting up a voltage reference Figure 7: Typical application for input signals referenced to ground Figure 8: Typical 2-wire application for input signals referenced to ground Figure 9: Block diagram of AM460 Figure 10: Pinout Figure 11: Application for input signals referenced to ground (protected output stage, impedance converter etc.) Figure 12: Complex configuration as a peripheral processor IC Figure 13: Conversion of a 0.5...4.5V sensor signal 3 7 8 10 10 11 13 14 16 16 17 17 17 analog microelectronics April 2003 2/18 Industrial Converter and Protector IC AM460 FEATURES GENERAL DESCRIPTION • 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 AM460 is a universal converter and amplifier IC with a number of additional functions. The IC basically consists of an amplifier, whose gain can be set externally, and parallel output stages which can condition 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 current loop (e.g. 0/4–20mA) signals to be produced relatively easily. BLOCK DIAGRAM VREF SET 16 15 VSET 13 CVREF 1 AM460 CVSET I 2 OP2 11 10 Voltage Reference 9 VBG V INP RS+ VCC RS- 8 IOUT 3 OP1 4 INN OP3 5 OUTAD 6 7 INDAI INDAV 12 VOUT 14 GND Figure 1: Block diagram of AM460 analog microelectronics Analog Microelectronics GmbH An der Fahrt 13, D – 55124 Mainz Internet: http://www.analogmicro.de Phone: +49 (0)6131/91 073 – 0 Fax: +49 (0)6131/91 073 – 30 E–mail: [email protected] April 2003 3/18 Rev. 1.1 Industrial Converter and Protector IC AM460 ELECTRICAL SPECIFICATIONS Tamb = 25°C, VCC = 24V, VREF = 5V, IREF = 1mA (unless otherwise stated), currents flowing into the IC are negative Parameter Symbol Supply Voltage Range VCC Quiescent Current ICC Conditions Min. Typ. 6 Tamb = – 40...+85°C, IREF = 0mA Max. Unit 35 V 1.5 mA Temperature Specifications Operating Tamb –40 85 °C Storage Tst –55 125 °C Junction TJ Thermal Resistance Θja DIL16 plastic package 70 °C/W Θja SO16 narrow plastic package 140 °C/W VREF VSET not connected 4.75 5.00 5.25 V VREF10 VSET = GND, VCC ≥ 11V 9.5 10.0 10.5 V VREF10 V 150 °C Voltage Reference Voltage Trim Range VREFADJ Current IREF* VREF vs. Temperature dVREF/dT Line Regulation Load Regulation 4.5 0 Tamb = – 40...+85°C ±90 10.0 mA ±140 ppm/°C dVREF/dV VCC = 6V...35V 30 80 ppm/V dVREF/dV VCC = 6V...35V, IREF ≈ 5mA 60 150 ppm/V 0.05 0.10 %/mA dVREF/dI dVREF/dI IREF ≈ 5mA 0.06 0.15 %/mA CL 1.9 2.2 5.0 µF Internal Reference VBG 1.20 1.27 1.35 V VBG vs. Temperature dVBG/dT ±60 ±140 ppm/°C Load Capacitance Current/Voltage Source OP2 Tamb = – 40...+85°C Current Source: ICV = VBG/RSET, from Figure 5 Adjustable Current Range ICV* 0 10 mA Output Voltage VCV VCC < 19V VBG VCC – 4 V VCV VCC ≥ 19V VBG 15 V VCV VCC < 19V 0.4 VCC – 4 V VCV VCC ≥ 19V 0.4 15 V Voltage Source: VCV = VBG (1 + R7 / R6), from Figure 6 Adjustable Voltage Range Output Current Load Capacitance ICV* Source ICV Sink CL Source mode 0 1 10 mA –100 µA 10 nF Operational Amplifier Gain Stage (OP1) Adjustable Gain GGAIN Input Range IR VCC < 10V 0 VCC – 5 V IR VCC ≥ 10V 0 5 V ±0.5 ±2 mV ±3 ±7 µV/°C Power Supply Rejection Ratio PSRR Offset Voltage VOS VOS vs. Temperature dVOS/dT 1 analog microelectronics 80 90 dB April 2003 4/18 Industrial Converter and Protector IC Parameter Symbol Conditions AM460 Min. Typ. Max. Unit 10 25 nA 7 20 pA/°C Operational Amplifier Gain Stage (OP1) (cont.) Input Bias Current IB IB vs. Temperature dIB/dT Output Voltage Limit VLIM Output Voltage Range Load Capacitance VREF V VOUTAD VCC < 10V 0 VCC – 5 VOUTAD VCC ≥ 10V 0 VREF V 250 pF CL V Operational Amplifier Output Stage (OP3) Internal Gain GOP Input Range IR VCC < 11V 0 VCC – 5 V IR VCC ≥ 11V 0 6 V ±0.5 ±2 mV Power Supply Rejection Ratio PSRR Offset Voltage VOS 2.15 80 2.20 2.25 90 dB VOS vs. Temperature dVOS/dT ±3 ±7 µV/°C Input Bias Current IB 10 25 nA IB vs. Temperature dIB/dT 20 pA/°C Output Voltage Range VOUT VCC < 19V 0 7 VCC – 5 V VOUT VCC ≥ 19V 0 14 V Output Current Limitation ILIM VOUT ≥ 10V 5 10 mA Output Current IOUT 0 ILIM mA Load Resistance RL 2 Load Capacitance CL 7 kΩ 500 nF V/I Converter Internal Gain GVI Trim Range 0.125 Adjustable by R0 0.75 1.00 350 1.25 Voltage Range at R0 FS VR0FS Offset Voltage VOS β F ≥ 100 ±2 ±4 mV VOS vs. Temperature dVOS/dT β F ≥ 100 ±7 ±14 µV/°C Input Resistance RIN 120 160 kΩ RIN vs. Temperature dRIN/dT 0.2 0.3 kΩ/°C Output Offset Current IOUTOS 3-wire operation –25 –35 µA IOUTOS vs. Temperature dIOUTOS/dT 3-wire operation 16 26 nA/°C Output Offset Current IOUTOS 2-wire operation 9.5 14 µA IOUTOS vs. Temperature dIOUTOS/dT 2-wire operation 6 8 nA/°C Output Control Current IOUTC 2-wire operation, VR0/100mV 6 8 µA IOUTC vs. Temperature dIOUTC/dT 2-wire operation –15 nA/°C Output Voltage Range VOUT VOUT = RL IOUT, VCC < 18V 0 VCC – 6 V VOUT VOUT = RL IOUT, VCC ≥ 18V 0 12 V Output Current Range FS IOUTFS IOUT = VR0/R0, 3-wire operation Output Resistance ROUT Load Capacitance CL analog microelectronics 750 –10 0.5 0 mV 20 mA 1.0 MΩ 500 nF April 2003 5/18 Industrial Converter and Protector IC Parameter Symbol Conditions AM460 Min. Typ. Max. Unit SET Stage Internal Gain GSET Input Voltage VSET 0.5 1.15 V Offset Voltage VOS ±0.5 ±1.5 mV VOS vs. Temperature dVOS/dT ±1.6 ±5 µV/°C Input Bias Current IB 8 20 nA IB vs. Temperature dIB/dT 7 18 pA/°C 0 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 35 V Protection against reverse polarity Ground vs. VS vs. VOUT Ground vs. VS vs. IOUT Current with reverse polarity 35 V Ground = 35V, VS = IOUT = 0 4.5 mA Ideal input 0.05 0.15 %FS Typ. Max. Unit System Parameters Nonlinearity * In 2-wire operation a maximum current of IOUTmin – ICC is valid BOUNDARY CONDITIONS Parameter Sense Resistor Stabilisation Resistor Load Resistor Symbol R0 IOUTFS = 20mA R0 c = 20mA/IOUTFS R5 IOUTFS = 20mA R5 c = 20mA/IOUTFS RL Only for 3-wire operation Sum Gain Resistors R1 + R2 Sum Offset Resistors R3 + R4 VREF Capacitor Conditions Min. 17 27 38 Ω c ⋅ 17 c ⋅ 27 c ⋅ 38 Ω 35 40 45 Ω c ⋅ 35 c ⋅ 40 c ⋅ 45 Ω 0 600 Ω 20 200 kΩ 20 C1 Ceramic Output Capacitor C2 Only for 2-wire operation D1 Breakdown Voltage VBR T1 Forward Current Gain βF BCX54/55/56, for example 200 kΩ 1.9 2.2 5.0 µF 250 nF 90 100 35 50 50 150 V DETAILED DESCRIPTION OF FUNCTIONS AM460 is a modular, universal converter and protector IC which has been specially developed for the conditioning of voltage signals referenced to ground. It has been conceived for both 2- and 3-wire operation1 in industrial applications (cf. application on page 8). The functions of AM460 are depicted in the block diagram (Figure 2) which also illustrates how few external components are required for the operation of this particular device. Electrical specifications for the external components are given on page 6. 1 The principle of AM460 is such that only the current output can be used in 2-wire operation. analog microelectronics April 2003 6/18 Industrial Converter and Protector IC VREF VCVREF R3 C1 AM460 R4 VS VSET 1 15 13 16 AM460 VCVSET I 2 OP2 11 R0 10 Voltage Reference 9 VBG V VINP 8 T1 D1 3 OP1 OP3 5 4 6 R1 R2 VOUTAD 7 VOUT 12 14 R5 IOUT VINDAI VINDAV Ground Figure 2: Block diagram of AM460 with external components (3-wire circuit for current output) AM460 consist of several modular function blocks (operational 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: VOUTAD = VINP ⋅ GGAIN with GGAIN = 1 + R1 R2 (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 polarity 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: VOUT = GOP ⋅ VINDAV (2) with VINDAV the voltage at pin INDAV (OP3 input). 3. The voltage-to-current converter (V/I converter) provides 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 analog microelectronics April 2003 7/18 Industrial Converter and Protector IC AM460 reduce power dissipation the transistor 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 internal voltage reference and an external voltage divider as shown in Figure 2, for example). External resistor R0 permits the output current to be finely adjusted with parallel operation of current and the voltage output. For the output current provided by T1 the following ratio applies: I OUT = V VINDAI + I SET with I SET = SET 8R0 2R 0 (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 sensors, 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 external 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-wire system signal source and conditioning IC GND ≠ Ground VCC ≠ VS 3-wire system signal source and conditioning IC VCC IOUT GND RL VS Ground GND = Ground VCC = VS IOUT RL VCC = VS Ground = GND Figure 3: Difference between 2- and 3-wire operation 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 amplification of the transistors used are compensated for internally by the V/I converter. 2 analog microelectronics April 2003 8/18 Industrial Converter and Protector IC AM460 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: VCC = VS − I OUT (VIN ) RL (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 external resistors R1 and R2. The transfer function for the output voltage is calculated by multiplying Equations 1 and 2 as follows: VOUT = VINP ⋅ GGAIN ⋅ GOP (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 converter pin VSET as shown in Figure 2 the values of the output current according to Equation 3 are as follows: I OUT (VINDAI = 0 ) = I SET = VREF R4 ⋅ 2R0 R3 + R4 (6) and thus for the ratio of the resistors R3/R4: R3 VREF = −1 R4 2R0 I SET (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 : I OUT = VINP GGAIN R + I SET with GGAIN = 1 + 1 8 R0 R2 (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: VS ≥ VOUT max + 5V analog microelectronics (9) April 2003 9/18 Industrial Converter and Protector IC RL [Ω] RL ≤ VS − VCCmin IOUTmax AM460 VCCmin = 6V RLmax = 600Ω IOUTmax = 20mA 600 300 Operating range 0 0 6 12 18 24 35 VS [V] Figure 4: Working range in conjunction with the load resistor • When using current output pin IOUT (in conjunction with the external transistor) the value of VS is dependent on that of the relevant load resistor RL (max. 600Ω) used by the application. The minimum system supply voltage VS is then: VS ≥ I OUT max RL + VCC min (10) Here, IOUTmax stands for the maximum output current and VCCmin for the minimum IC supply voltage which is dependent on the selected reference voltage: VCC min ≥ VREF + 1V (11) The working range resulting from Equation 10 is described in Figure 4. Example calculations and typical values for the external components can be found in the example applications from page 12 onwards. Connecting OP2 as a current source The additional operational amplifier OP2 can easily be connected up as a constant current source. Using the cir- OP2 connected as current source IS 1 AM460 2 OP2 RSET VBG Figure 5: Connecting up a constant current source analog microelectronics April 2003 10/18 Industrial Converter and Protector IC AM460 cuit in Figure 5 the following applies: IS = V BG 1 . 27 V = R SET R SET (12) The bridge symbol represents the component to be supplied with current (e.g. a piezoresistive sensing element or temperature sensor). Example 1: A supply current of IS = 1mA is to be set. Using Equation 12 the following value is calculated for external resistor RSET, which in turn stipulates the size of the current: R SET = V BG 1 . 27 V = = 1 . 27 k Ω 1mA IS Connecting OP2 as a voltage reference In addition to the integrated voltage reference OP2 can also be used to supply voltage to external components such as A/D converters and microprocessors, for example. Lower voltages can be generated (e.g. 3.3V) which with the increasing miniaturisation of devices and need for ever lower levels of power dissipation in digital components is today of growing importance. The additional operational amplifier OP2 can easily be connected up as a voltage reference. Using the circuit in Figure 6 the following applies: R V CVREF = V BG 1 + 6 = 1 . 27 V R7 R 1 + 6 R 7 (13) Example 2: A voltage of VCVREF = 3.3V is to be set. Using Equation 13 the following ratio is calculated for external resistors OP2 connected as voltage reference VCVREF 1 µP AM460 R6 2 OP2 R7 VBG Figure 6: Connecting up a voltage reference analog microelectronics April 2003 11/18 Industrial Converter and Protector IC AM460 R6 and R7: R 6 V CVREF = − 1 ≈ 2 .6 − 1 = 1 .6 R7 V BG The following example values are produced for the resistors: R7 = 10kΩ R6 = 16kΩ OPERATING AM460: IMPORTANT POINTS TO NOTE 1. When using AM460 it is imperative that external capacitor C1 (a top-grade ceramic capacitor) is always connected (cf. Figure 2). Care must be taken that the value of the capacitor, also 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 C2 must also be used (cf. Figure 8) 2. In a 2-wire setup the power consumption of the entire system (AM460 plus all external components, including the configuration resistors) must not exceed the sum of IOUTmin (usually 4mA). 3. All AM460 function blocks not required 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 referenced to ground. The unused blocks (e.g. OP2) have been set to defined operating points. 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: R VOUT = GV VINP with GV = GGAIN GOP = 1 + 1 ⋅ 2.2 R2 (14) For output current IOUT the following applies according to Equation 3: I OUT = VINP ⋅ R GI + I SET with GI = GGAIN = 1 + 1 and I SET = 0 8 R0 R2 analog microelectronics April 2003 12/18 Industrial Converter and Protector IC AM460 3-wire connection C1 1 16 15 13 VS ISET = 0 AM460 I 2 OP2 11 R0 10 Voltage Reference 9 VBG V VINP 8 T1 D1 3 OP1 6 5 4 Single-ended input voltage 7 VOUT 12 OP3 14 R5 IOUT R1 R2 RL Connections setting unused function blocks to a defined operating point Ground Figure 7: Typical application for input signals referenced to ground Example 3: To obtain a signal of VINP = 0...1V at the OP1 input the external components are to be dimensioned in such a way that the output current has a range of 0...20mA (i.e. ISET = 0 ⇒ SET = GND) and the output voltage one of 0...10V. Using Equation 14 the output voltage is defined as follows: R VOUT R 10V VOUT = VINP ⋅ 1 + 1 ⋅ 2.2 ⇒ 1 = −1= − 1 ≈ 3.55 R2 2.2 ⋅ 1V R2 2.2 ⋅ VINP i.e. GGAIN = 1 + R1 = 4.55 R2 The following then applies to the output current: I OUT = VINP ⋅ G GI + I SET = VINP ⋅ GAIN 8R0 8R0 ⇒ R0 = VINP ⋅ GGAIN 4.55 = 1V ≈ 28.44Ω 8I OUT 8 ⋅ 20mA Observing the boundary conditions, the following values are obtained for the external components: R0 ≈ 28.44Ω R5 = 39Ω R1 ≈ 35.5kΩ RL = 0...600Ω R2 = 10kΩ C1 = 2.2µF analog microelectronics April 2003 13/18 Industrial Converter and Protector IC AM460 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 resistor RL which connects current output IOUT to the system ground. For output current IOUT the following applies according to Equation 3: I OUT = VINP ⋅ R GI V R4 + I SET with GI = GGAIN = 1 + 1 and I SET = REF ⋅ 8 R0 2R0 R3 + R4 R2 Example 4: To obtain a signal of VINP = 0...1V at the OP1 input the external components are to be dimensioned in such a way that the output current has a range of 4...20mA. I OUT = VINP ⋅ G GI + I SET = VINP ⋅ GAIN + 4mA 8 R0 8R0 With R0 = 27Ω Equation 7 produces the following: R3 VREF 5V = −1 = − 1 ≈ 22.15 R4 2R0 I SET 2 ⋅27Ω ⋅ 4mA and thus the following value for the gain to be set: C1 1 R3 15 13 R4 VS 16 AM460 I 2 OP2 C2 R0 11 10 Voltage Reference 9 VBG V VINP 8 T1 D1 3 OP1 OP3 5 4 Single-ended input voltage R1 R2 IC ground: GND 6 7 } System ground: Ground 12 14 Different potentials! Connections setting unused function blocks to a defined operating point 2-wire connection R5 IOUT RL GND Ground Figure 8: Typical 2-wire application for input signals referenced to ground analog microelectronics April 2003 14/18 Industrial Converter and Protector IC GGAIN = 8R0 I OUT max − I SET 16mA = 8 ⋅ 27Ω ⋅ = 3.456 1V VINP ⇒ AM460 R1 = 3.456 − 1 = 2.456 R2 Observing the boundary conditions, the following values are obtained for the external components: R1 ≈ 24.56kΩ R0 = 27Ω R2 = 10kΩ R5 = 39Ω R3 ≈ 44.3kΩ RL = 0...600Ω analog microelectronics R4 = 2kΩ C1 = 2.2µF C2 = 100nF April 2003 15/18 Industrial Converter and Protector IC AM460 BLOCK DIAGRAM AND PINOUT VREF SET 16 15 VSET 13 CVREF 1 AM460 CVSET I 2 OP2 11 10 Voltage Reference 9 VBG V INP RS+ VCC RS- 8 IOUT 3 OP1 4 INN OP3 5 6 OUTAD 7 12 VOUT 14 INDAI INDAV GND Figure 9: Block diagram of AM460 CVREF 1 16 SET CVSET 2 15 VREF INP 3 14 GND INN 4 13 VSET OUTAD 5 12 VOUT INDAI 6 11 RS+ INDAV 7 10 VCC IOUT 8 9 RS− Figure 10: Pinout PIN NAME 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 CVREF CVSET INP INN OUTAD INDAI INDAV IOUT RSVCC RS+ VOUT VSET GND VREF SET EXPLANATION Current/Voltage reference Current/Voltage reference set Positive input Negative input System amplification output Current output stage input Voltage output stage input Current output Sensing resistor Supply voltage Sensing resistor + Voltage output Reference voltage source set IC ground Reference voltage source output Output offset current set Table 1: AM460 pinout analog microelectronics April 2003 16/18 Industrial Converter and Protector IC AM460 EXAMPLES OF POSSIBLE APPLICATIONS • Conditioning signals referenced to ground (protected output stage, impedance converter etc.) 6...35V 0/4...20mA VIN = 0...1, 0...5V others Protection agains short-circuiting and reverse polarity AM460 0...5/10V Figure 11: Application for input signals referenced to ground (protected output stage, impedance converter etc.) • Complex configuration as a peripheral processor IC VCVREF = 3.3V µP 6...35V VREF = 5V 0/4...20mA D Protection agains short-circuiting and reverse polarity AM460 A 0...5/10V Figure 12: Complex configuration as a peripheral processor IC • Conversion of a 0.5...4.5V sensor signal 6...35V VREF = 5V 4...20mA Protection agains short-circuiting and reverse polarity VOUT = 0.5...4.5V Sensor AM460 1...6V Figure 13: Conversion of a 0.5...4.5V sensor signal analog microelectronics April 2003 17/18 Industrial Converter and Protector IC AM460 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 Microelectronics 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. analog microelectronics April 2003 18/18