AD AM401 Industrial voltage amplifier ic Datasheet

INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
PRINCIPLE FUNCTION
Amplification and conversion of differential signals referenced to ground
to adjustable industrial voltages (0...Vcc-5V, e.g. 0...5/10V etc.)
Variable current/voltage source and integrated protective circuitry
VCC = 6…35V
Differential
input voltage 400mV
AM401
Single-ended
input voltage 0...5V
VREF= 5/10V
VOUT = 0...VCC- 5V
adjustable e.g. 0...10V
IS = 0...10mA
TYPICAL APPLICATIONS
•
•
•
•
•
•
Transducer for sensor applications, for example
Analog output stage for microprocessors
Impedance converter
Voltage regulator with voltage and current sources
Analog front-end and back-end IC (Frame ASIC concept [1])
Adjustable output stage IC
analog microelectronics
Analog Microelectronics GmbH
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Internet: http://www.analogmicro.de
Phone:
Fax:
Email:
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March 2006
1/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
CONTENTS
GENERAL DESCRIPTION .................................................................................................3
BLOCK DIAGRAM .............................................................................................................3
ELECTRICAL SPECIFICATIONS......................................................................................4
BOUNDARY CONDITIONS ................................................................................................6
DETAILED DESCRIPTION OF FUNCTIONS.....................................................................7
AM401’s transfer function............................................................................................................................................... 8
Setting the instrumentation amplifier............................................................................................................................. 8
Setting the voltage amplification ..................................................................................................................................... 9
Selecting the supply voltage ............................................................................................................................................. 9
Points to note: initial operation of AM401 ................................................................................................................... 10
APPLICATIONS................................................................................................................10
Application 1 – Differential input signal, voltage output signal of 0...5/10V............................................................. 10
Application 2 – Voltage output signal of 0...5/10V, current-driven sensing element................................................ 10
Application 3 – Differential input signal, voltage output signal of 0.5...4.5V............................................................ 10
Application 4 – Input voltage (referenced to ground) of 0...1V and output voltage of 0...10V................................ 10
Application 5 – Connecting up OP2 as a voltage reference ........................................................................................ 10
CIRCUIT TOPOLOGY......................................................................................................10
Topology of the 0...5/10V application ........................................................................................................................... 10
Topology of the 0.5...4.5V application........................................................................................................................... 10
BLOCK DIAGRAM AND PINOUT....................................................................................10
EXAMPLE APPLICATIONS .............................................................................................10
DELIVERY........................................................................................................................10
PACKAGE DIMENSIONS .................................................................................................10
FURTHER READING .......................................................................................................10
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Mars 2006
2/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
FEATURES
GENERAL DESCRIPTION
• Supply voltage range: 6...35V
• Wide operating temperature range:
–40°C...+85°C
• Adjustable voltage reference:
5 to 10V
• Additional current/voltage source
• Instrumentation amplifier input
CMVI: 1.5...Vcc-3V
• Operational amplifier input
Vin: 0...Vcc-5V
• Adjustable gain and offset
• Adjustable output voltage range:
0...Vcc-5V, e.g. 0.5...4.5V, 0...5/10V
• Individually configurable function
modules
• Protection against reverse polarity
• Output current limitation
• Short-circuit protection
• Protection against ESD
• RoHS compliant
AM401 and AM401P [2] are universal voltage
transmitters designed for differential bridge signal
conditioning. The two devices differ in their offset
and offset drift values. The ICs are modular and
their functional units individually accessible. Both
ICs consist of a high-precision instrumentation
amplifier for differential input signals and an
operational amplifier for input signals referenced
to ground. A robust reference voltage source
(adjustable between 5 and 10V) can be used to
power external components. An operational
amplifier stage whose gain is also adjustable acts
as an output. The devices also contain an
additional operational amplifier which can be used
as a current or voltage source. The IC is protected
against reverse polarity and has an integrated
output current limit. Standard industrial voltages
(e.g. 0–5/10V, 0.5–4.5V) can be easily generated
using transmitter ICs AM401 and AM401P.
BLOCK DIAGRAM
AM401
CVSET
VSET
VREF
1
12
15
_
2
VBG
IN+
_
IN
CVREF
OP2
+
Voltage Reference
11
VCC
+
_OP1
8
VOUT
+
3
_ IA
4
14
GND
13
5
6
7
ZA OUTIA INOP GAIN
Figure 1: Block diagram of AM401 (individually configurable function)
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March 2006
3/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
ELECTRICAL SPECIFICATIONS
Tamb = 25°C, VCC = 24V, VREF = 5V, IREF = 1mA (unless otherwise stated)
Parameter
Symbol
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
SSOP plastic package
120
°C/W
Θja
SO16 narrow plastic package
140
°C/W
VREF
VSET not connected
4.90
5.00
5.10
VREF
VSET = GND, VCC ≥ 11V
9.8
10.0
10.2
V
10.0
mA
ppm/°C
150
°C
Voltage Reference
Voltage
Current
IREF
VREF vs. Temperature
dVREF/dT
Tamb = – 40...+85°C
±90
±140
Line Regulation
dVREF/dV
VCC = 6V...35V
30
80
ppm/V
dVREF/dV
VCC = 6V...35V, IREF ≈ 5mA
60
150
ppm/V
Load Regulation
dVREF/dI
dVREF/dI
Load Capacitance
0.2
V
0.05
0.10
%/mA
0.06
0.15
%/mA
1.9
2.2
5.0
µF
1.20
1.27
1.35
V
±60
±140
ppm/°C
0
10
mA
IREF ≈ 5mA
CL
Current/Voltage Source (OP2)
Internal Reference
VBG
VBG vs. Temperature
dVBG/dT
Tamb = – 40...+85°C
Current Source: ICV = VBG/REXT (see page 10 for details)
Adjustable Current Range
ICV
Output Voltage
VCV
VCC < 18V
VBG
VCC – 5
V
VCV
VCC ≥ 18V
VBG
13
V
Voltage Source: VCV = VBG (1+R4/R3) (see page 13 for details)
Adjustable Voltage Range
Output Current
Load Capacitance
VCV
VCC < 18V
0.4
VCC – 5
V
VCV
VCC ≥ 18V
0.4
13
V
ICV
Source
ICV
Sink
CL
Source mode
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0
1
10
mA
–100
µA
10
nF
Mars 2006
4/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
ELECTRICAL SPECIFICATIONS
Parameter
Symbol
Conditions
Min.
Typ.
Max.
4.9
5
5.1
Unit
Instrumentation Amplifier (IA) AM401
Internal Gain
GIA
Differential Input Voltage Range
VIN
0
±400
Common Mode Input Range
CMIR
VCC < 9V, ICV < 2mA
1.5
VCC – 3
V
CMIR
VCC ≥ 9V, ICV < 2mA
1.5
6.0
V
Common Mode Rejection Ratio
CMRR
80
90
Power Supply Rejection Ratio
PSRR
80
90
Offset Voltage
VOS
VOS vs. Temperature
dVOS/dT
Input Bias Current
IB
IB vs. Temperature
dIB/dT
Output Voltage Range*
VOUTIA
±1.5
dB
dB
±6
–0.35
VCC < 9V, RLIA ≤ 10kΩ
0*
0*
VOUTIA
VCC ≥ 9V, RLIA ≤ 10kΩ
Minimum Output Voltage
VOUTIAmin
Without external load resistance RLIA
Load Capacitance
CL
5
mV
µV/°C
±5
–120
mV
–300
nA
–0.8
nA/°C
VCC – 3
V
6
V
17
mV
250
pF
Instrumentation Amplifier (IA) AM401P
Internal Gain
GIA
4.9
5
5.1
Differential Input Voltage Range
VIN
0
±400
mV
Common Mode Input Range
CMIR
VCC < 9V, ICV < 2mA
1.5
VCC – 3
V
CMIR
VCC ≥ 9V, ICV < 2mA
1.5
6.0
V
Common Mode Rejection Ratio
CMRR
80
90
dB
Power Supply Rejection Ratio
PSRR
80
90
dB
Offset Voltage
VOS
VOS vs. Temperature
dVOS/dT
Input Bias Current
IB
IB vs. Temperature
dIB/dT
Output Voltage Range*
VOUTIA
–120
–0.35
VCC < 9V, RLIA ≤ 10kΩ
0*
0*
VOUTIA
VCC ≥ 9V, RLIA ≤ 10kΩ
Minimum Output Voltage
VOUTIAmin
Without external load resistance RLIA
Load Capacitance
CL
5
±1,5
mV
±5
µV/°C
–300
nA
–0.8
nA/°C
VCC – 3
V
6
V
17
mV
250
pF
VOUTIA
V
Zero Adjust Stage (IA)
Internal Gain
GZA
Input Voltage
VZA
1
VZA ≤ VOUTIA – GIA VIN
0
Offset Voltage
VOS
±0.5
±2.0
mV
VOS vs. Temperature
dVOS/dT
±1.6
±5
µV/°C
Input Bias Current
IB
38
100
nA
IB vs. Temperature
dIB/dT
24
75
pA/°C
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Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
ELECTRICAL SPECIFICATIONS
Parameter
Symbol
Conditions
Min.
Typ.
Max.
Unit
VCC – 5
V
Voltage Output Stage (OP1)
Adjustable Gain
GOP
Input Range
IR
VCC < 10V
IR
VCC ≥ 10V
Power Supply Rejection Ratio
1
0
0
PSRR
80
5
90
V
dB
Offset Voltage
VOS
VOS vs. Temperature
dVOS/dT
±0.5
±2
mV
±3
±7
µV/°C
Input Bias Current
IB
5
12
nA
IB vs. Temperature
dIB/dT
Output Voltage Range
VOUT
VCC < 18V
0
VCC – 5
10
pA/°C
V
VOUT
VCC ≥ 18V
0
13
V
Output Current Limitation
ILIM
VOUT ≥ 10V
Output Current
IOUT
0
Load Resistance
RL
2
Load Capacitance
CL
3.5
5
7
10
mA
ILIM
mA
kΩ
500
nF
Ground vs. VS vs. VOUT R1≥20 kΩ
35
V
VOUT ≥ 10V
10
mA
0.15
%FS
Protection Functions
Protection against reverse polarity
Output current limitation
ILIM
System Parameters
Nonlinearity
Ideal input
0.05
* Depending on external load resistance at output IA (RLIA ≤ 10kΩ ⇒ VOUTIA < 3mV); internal load resistance is ≈ 100kΩ
Currents flowing into the IC are negative
BOUNDARY CONDITIONS
Parameter
Symbol
Max.
Unit
Sum Gain Resistors
R1 + R2
Conditions
Min.
90
Typ.
200
kΩ
Sum Reference Adjustment Resistors
R3 + R4
20
200
kΩ
Stabilization Capacitance @ VREF
C1
1.9
5.0
µF
VIA Capacitance
C2
10
100
pF
2.2
IMPORTANT CONDITION:
*The reference output always has to source 1mA.
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Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
DETAILED DESCRIPTION OF FUNCTIONS
AM401 is a monolithically integrated voltage transmitter which has been designed for the
conditioning of differential bridge voltages and for the conversion of voltage signals referenced to
ground. By varying just a few external components the output voltage can be adjusted over a wide
range. All of the function blocks are individually accessible, enabling them to be used as functional
units or, using the relevant external circuitry, configured as an application-specific device. Typical
applications and values for external components are given in the examples described in the
following.
In essence AM401 consists of 4 functional blocks as shown in Figure 1. The individual blocks are
as follows:
1. The core element of AM401 is its high-precision instrumentation amplifier (IA) with an internal
gain of GIA and the ability to set the reference potential of the amplifier externally (pin ZA). The
IA acts as an input stage for differential voltage signals.
2. There is also an operational amplifier stage (OP1). OP1’s gain of GOP1 can be set using external
resistors R1 and R2 (see Figure 2). The operational amplifier output has been designed in such a
way that with certain loads it can be set down to zero. In addition, the output stage can drive up
to a maximum of 10mA without an external transistor having to be connected. An output current
limit has been implemented as a protective feature which guards the IC at the output in the event
of a short-circuit.
3. AM401’s voltage reference permits voltage to be supplied by external components (such as
sensors, microprocessors, etc.). The reference voltage VREF has a value of either 5V or 10V.
External capacitance C1 acts as a reference voltage stabilizer. It must also be connected when
the voltage reference is not in use (see: Figure 2).
4. An additional operational amplifier (OP2) can be used as a current or voltage source for the
supply of external components. OP2’s positive input is connected internally to voltage VBG so
that the output current or voltage can be set across a wide range using one or two external
resistors. Descriptions of the relevant applications can be found on the following pages. The
operational amplifier output has a sufficiently high drive power.
One of AM401’s main features is its range of integrated protective circuits which make the IC an
effective output stage.
•
Pins VOUT, VCC and GND are protected against reverse polarity across the entire supply
voltage range without the need for any additional external components.
•
The output of the IC is protected against short-circuiting.
•
All pins (with the exception of VOUT, VCC and GND) are protected by internal ESD diodes.
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Mars 2006
7/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
AM401’s transfer function
In compliance with Figure 2 the transfer function for AM401 when used as an amplifier for
differential signals with a voltage output is:
where:
VOUT = GOP (G IAVIN + VZA )
(1)
G = G IAGOP = G IA (1 + R1 R2 )
(2)
C1
R3
VOFFSET
R4
AM401
2
12
1
VSET
CVREF
Voltage Reference
OP2
RIN
VIN
4
IN+
+
IN _
_
RB
VCC
11
VCC
8
VOUT
+
VBG
3
VREF
_
CVSET
RA
15
+
IA
GND
14
VOUT
OP1
_
OUTIA
ZA
13
6
5
C2
INOP GAIN
7
R2
R1
Ground
Figure 2: The general functions of AM401
Setting the instrumentation amplifier
The transfer function of the instrumentation amplifier is determined by:
VOUTIA = GIAVIN + VZA
with an offset voltage of VZA which can be set at pin ZA. With the circuitry shown in Figure 2 and
using the additional operational amplifier the offset voltage is determined thus:
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Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
VOFFSET = VBG −
R4
(VREF − VBG )
R3
(3)
The following applies to the IC’s actual output voltage VOUT (transfer function of OP1):
VOUT = GOP ⋅VINOP
(4)
R
with an adjustable gain of GOP: GOP = 1 + 1
R2
(5)
Setting the voltage amplification
The gain of operational amplifier stage OP1 can be set using the suitably selected external resistors
R1 and R2. If OP1 is connected up as a non-inverting amplifier (see: Figure2) output voltage VOUT at
pin VOUT is calculated as follows:
VOUT = VIN ⋅ GOP1 with GOP1 =
R1
+1
R2
where VIN is the voltage at OP1’s input pin INOP.
Selecting the supply voltage
In principle AM401 can be used across the entire supply voltage range defined herein. However,
depending on the output voltage selected and the circuitry of the remaining components certain
boundary conditions apply when selecting VCC:
•
When using voltage output pin VOUT the IC’s minimum supply voltage VCC necessary for the
operation of the device depends on the maximum output voltage VOUTmax required by the
application. The following applies:
VCC ≥ VOUT max + 5V
•
(6)
If the additional operational amplifier OP2 is used as a voltage reference or current source, the
minimum supply voltage selected (VCC) depends on the maximum voltage at pin CVREF. The
following applies:
VCC ≥ VCVREF max + 5V
(7)
When using pin VOUT and operational amplifier OP2 as a voltage reference or current source the
higher value of Vcc must be set.
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Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
Points to note: initial operation of AM401
1. When operating AM401 it is imperative that external stabilization capacitance C1 (a high-grade
ceramic capacitor) is must always connected. Care must be taken that the value of the
capacitance does not lie beyond its given range, even across the range of temperature (see
Boundary Conditions). The maximum current drawn from the reference must not exceed a value
of IREF = 10mA.
2. All of the AM401 function blocks not used by the application (e.g. OP2) must be connected up
to a defined (and permitted) potential. Unused blocks, such as the additional operational
amplifier (see Figure 3), must be configured. The two capacitances C1 and C2 must be
connected up in any event, even if the reference voltage source is not used.
3. When OP1 is in operation the load resistance at pin VOUT must be at least 2kΩ.
The values of external resistors R1, R2, R3 and R4 must be selected so that they lie within the
permitted range specified in the boundary conditions on.
1
AM401
C1
2
4
VSET
15
VREF
_
CVSET
Voltage Reference
OP2
+
VBG
3
12
CVREF
IN+
+
IN _
_ IA
GND
14
+
_OP1
OUTIA
ZA
13
6
5
C2
VCC
VOUT
11
VCC
8
VOUT
INOP GAIN
7
R2
R1
Ground
Figure 3: AM401 used as an industrial bridge amplifier
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Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
APPLICATIONS
Application 1 – Differential input signal, voltage output signal of 0...5/10V
With applications which require an output voltage of 0...5/10V the pin used to configure the
instrumentation amplifier offset (ZA) is connected to the IC’s Ground. Gain G is set using the two
external resistors R1 and R2:
G = G IA GOP = G IA (1 + R1 R2 )
(2)
If no offset voltage is present, the transfer function of the output voltage (Gl.1) is:
VOUT = G VIN
Using these equations the values of resistors R1 and R2 can be set as follows:
V
R1
= OUT − 1
R2 GIA VIN
Example 1: Input voltage (differential) of 0...50mV and output voltage range of 0...10V
If VIN = 0...50mV, R1/R2 = 39 and IREF ≥ 1mA the values of the external components are as follows:
R1 ≈ 117kΩ
R2 ≈ 3kΩ
GIA = 5
C1 = 2.2µF
C2 = 10nF
Example 2: Input voltage (differential) of 0...100mV and output voltage range of 0...5V
If VIN = 0...100mV, R1/R2 = 9 and IREF ≥ 1mA the values of the external components are as follows:
R1 ≈ 90kΩ
R2 ≈ 10kΩ
GIA = 5
C1 = 2.2µF
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C2 = 10nF
Mars 2006
11/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
Application 2 – Voltage output signal of 0...5/10V, current-driven sensing element
RREF
C1
1
AM401
2
VIN
4
15
VREF
IN+
+
IN _
_ IA
GND
14
+
_OP1
OUTIA
ZA
13
VCC
Voltage Reference
OP2
+
VBG
3
VSET
_
CVSET
RSET
12
CVREF
6
5
C2
VOUT
11
VCC
8
VOUT
INOP GAIN
7
R2
R1
Ground
Figure 4: Application for current-driven sensing elements
In this application the additional OP is used as a current source for a resistor measuring bridge. The
values of the external components have been calculated for an output voltage of 0...5V; the pin used
to configure the instrumentation amplifier offset (ZA) is connected to the IC’s Ground. Gain G is
set using the two external resistors R1 and R2:
G = G IA GOP = G IA (1 + R1 R2 )
(2)
If no offset voltage is present, the transfer function of the output voltage (Gl.1) is:
VOUT = G VIN
(1)
Using these equations the values of resistors R1 and R2 can be set as follows:
V
R1
= OUT − 1
R2 G IAV IN
Supply current IS for the sensor bridge can be determined using resistance RSET:
IS =
VBG
RSET
(8)
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Mars 2006
12/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
Example 3: Input voltage (differential) of 0...100mV and output voltage range of 0...5V
If VIN = 0...100mV, R1/R2 = 9, IS = 1.5mA VBG = 1.27V and IREF = 1mA the values of the external
components are as follows:
R1 ≈ 90kΩ
R2 ≈ 10kΩ
GIA = 5
C1 = 2.2µF
C2 = 10nF
RREF ≈ 5kΩ
RSET ≈ 846.7Ω
Application 3 – Differential input signal, voltage output signal of 0.5...4.5V
With applications which require an output voltage of 0.5...4.5V the pin used to configure the
instrumentation amplifier offset (ZA) is connected to voltage VOFFSET (Figure 5). Gain G is set using
the two external resistors R1 and R2:
G = G IA GOP = GIA (1 + R1 R2 )
(2)
The transfer function of output voltage VOUT is:
VOUT = G VIN + VOFFSET
(1)
The offset voltage (Equation 3) is calculated as:
R
VOFFSET = VBG − 4 ( VREF − VBG )
R3
⇒
VREF − VBG
R3
=
R4 VBG − VOFFSET
Using these equations the values of resistors R1 and R2 can be set as follows:
R1 VOUT − VOFFSET
=
−1
R2
GIA VIN
analog microelectronics
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
Internet: http://www.analogmicro.de
Phone:
Fax:
Email:
+49 (0)6131/91 073 – 0
+49 (0)6131/91 073 – 30
[email protected]
Mars 2006
13/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
C1
R3
VOFFSET
R4
1
AM401
2
VIN
4
VSET
15
VREF
_
CVSET
Voltage Reference
OP2
+
VBG
3
12
CVREF
IN+
+
IN _
_ IA
GND
14
+
_OP1
OUTIA
ZA
13
6
5
VOUT
11
VCC
8
VOUT
INOP GAIN
7
R2
C2
VCC
R1
Ground
Figure 5: Application as a bridge amplifier for an output voltage of 0.5...4.5V
Example 4: Input voltage (differential) of 0...250mV and output voltage range of 0.5...4.5V
If VIN = 0...250mV, IREF ≥ 1mA, R1/R2 = 2.2 and R3/R4 = 4.8 the values of the external components
are as follows:
R1 ≈ 100kΩ
R2 ≈ 47kΩ
R3 ≈ 75kΩ
R4 ≈ 15.5kΩ
C1 = 2.2µF
C2 = 10nF
VOFFSET = 0.5V
analog microelectronics
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
Internet: http://www.analogmicro.de
Phone:
Fax:
Email:
+49 (0)6131/91 073 – 0
+49 (0)6131/91 073 – 30
[email protected]
Mars 2006
14/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
Application 4 – Input voltage (referenced to ground) of 0...1V and output voltage of 0...10V
RREF
1
AM401
C1
2
4
15
VSET
VREF
_
CVSET
Voltage Reference
OP2
+
VBG
3
12
CVREF
IN+
+
IN _
_ IA
GND
14
+
_OP1
OUTIA
ZA
13
6
5
VCC
VOUT
11
VCC
8
VOUT
INOP GAIN
7
R2
R1
Ground
INOP = IN
Figure 6: AM401 with an OP input stage
For a signal of VIN = 0...1V at the OP1 input the external components are to be dimensioned in such
a way that there is an output voltage range of VOUT = 0...10V. Using the values in Equation 4 the
settable gain has a value of:
GOP1 =
VOUT max 10V
=
= 10
VIN max
1V
where VIN is the voltage at OP1 input pin INOP.
According to Equation 5 the below value is calculated for the resistance ratio of the adjustment
resistors:
R1
= GOP1 − 1 = 9
R2
With reference to the boundary conditions for external components given on page 6 the following
values are obtained:
R1 ≈ 90kΩ
R2 = 10kΩ
RREF = 5kΩ
C1 = 2.2µF
analog microelectronics
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
Internet: http://www.analogmicro.de
Phone:
Fax:
Email:
+49 (0)6131/91 073 – 0
+49 (0)6131/91 073 – 30
[email protected]
Mars 2006
15/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
Application 5 – Connecting up OP2 as a voltage reference
R4
In addition to the integrated voltage
reference of the AM401, the OP2 can also
be used as a voltage supply for external
components, such as A/D converters or
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.
If in addition to the 5/10V reference a
further voltage source is required to power
external
components
the
second
operational amplifier OP2 can be used to
this end.
VCVREF
OP2 connected as
voltage reference
AM401
_
2
R3
VBG
+
11
OP2
3
VIN
Figure 7: AM401’s OP2 as a voltage reference
This operational amplifier can be easily configured as a voltage reference. Using the circuit in
Figure 7 the following equation is given:

R 
V CVREF = V BG  1 + 4  = 1 . 27 V
R3 


R 
 1 + 4 
R3 

(9)
A voltage of VCVREF = 3.3V is to be set. With reference to Equation 9 the following ratio is obtained
for the external resistors R3 and R4:
R 4 V CVREF
=
− 1 ≈ 2 .6 − 1 = 1 .6
R3
V BG
With reference to the boundary conditions for external components given on page 6 the following
values are obtained for the resistors:
R3 = 10kΩ
R4 = 16kΩ
analog microelectronics
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
Internet: http://www.analogmicro.de
Phone:
Fax:
Email:
+49 (0)6131/91 073 – 0
+49 (0)6131/91 073 – 30
[email protected]
Mars 2006
16/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
CIRCUIT TOPOLOGY
Topology of the 0...5/10V application
VCC
C1
N.C. N.C.
N.C.
16 15 14 13
12
11
10
9
7
8
AM401
1
2
3
5
4
6
VOUT
R1
C2
R2
Ground
Figure 8: Circuit topology of a 0...5/10V output
Topology of the 0.5...4.5V application
VCC
C1
N.C. N.C.
N.C.
16
15 14 13
12
11
10
9
7
8
AM401
1
2
3
4
5
6
VOUT
R3
R1
R4
C2
R2
Ground
Figure 9: Circuit topology of a 0.5...4.5V output
analog microelectronics
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
Internet: http://www.analogmicro.de
Phone:
Fax:
Email:
+49 (0)6131/91 073 – 0
+49 (0)6131/91 073 – 30
[email protected]
Mars 2006
17/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
BLOCK DIAGRAM AND PINOUT
AM401
CVSET
VSET
VREF
1
12
15
_
2
VBG
IN+
_
IN
CVREF
OP2
+
Voltage Reference
11
VCC
+
_OP1
8
VOUT
+
3
_ IA
4
14
GND
13
6
5
7
ZA OUTIA INOP GAIN
Figure 10: Block diagram of AM401 (individually configurable function modules)
PIN
NAME
DESIGNATION
1
CVREF
Current/Voltage Reference
2
CVSET
Current/Voltage Reference Set
3
IN+
Positive Input
4
IN–
Negative Input
5
OUTIA
Instrumentation Amplifier Output
6
INOP
Operational Amplifier Input
7
GAIN
Gain Adjustment
8
VOUT
Voltage Output
9
N.C.
Not Connected
10
N.C.
Not Connected
11
VCC
Supply Voltage
12
VSET
Voltage Select
13
ZA
Zero Adjustment (Offset)
Pinout
AM401
Abbildung
11:
14
GND
IC Ground
15
VREF
Reference Voltage
16
N.C.
Not Connected
CVREF
CVSET
IN+
INOUTIA
INOP
GAIN
VOUT
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
N.C.
VREF
GND
ZA
VSET
VCC
N.C.
N.C.
Figure 11: AM401 Pin out
Table 1: Pin out
analog microelectronics
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
Internet: http://www.analogmicro.de
Phone:
Fax:
Email:
+49 (0)6131/91 073 – 0
+49 (0)6131/91 073 – 30
[email protected]
Mars 2006
18/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
EXAMPLE APPLICATIONS
•
Application as a voltage converter [3]
VCC=6...35V
Single-ended signal
0...VCC-5V
Protection against
short circuiting and
reverse polarity
0...VCC -5V
(adjustable)
e.g. 0..5/10V
AM401
Figure 12: Application as a voltage converter for signals referenced to ground
•
Application as an amplifier IC and impedance converter
I=1,5mA
VCC=6...35V
Protection against
short circuiting and
reverse polarity
0...VCC -5V
(adjustable)
e.g. 0..5/10V
AM401
Figure 13: Application as an amplifier IC and impedance converter for differential signals
•
Application as a processor interface
VREF=5/10V
VCC=6...35V
D
Protection against
short circuiting and
reverse polarity
0...VCC -5V
(adjustable)
e.g. 0..5/10V
AM401
A
Figure 14: Application as a processor interface
analog microelectronics
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
Internet: http://www.analogmicro.de
Phone:
Fax:
Email:
+49 (0)6131/91 073 – 0
+49 (0)6131/91 073 – 30
[email protected]
Mars 2006
19/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
•
Application as a processor periphery IC
VCV REF = 3.3V
VCC=6...35V
VR EF = 5V
µP
D
AM401
A
Protection against
short circuiting and
reverse polarity
0...VCC -5V
(adjustable)
e.g. 0..5/10V
Figure 15: Application as a processor periphery IC
•
Application as a front-end/back-end IC for microprocessors
I=1.5mA
VCC=6...35V
0...VCC -5V
(adjustable)
e.g. 0..5/10V
AM401
VREF = 5V
Protection against
short circuiting and
reverse polarity
µP
Figure 16: Application as an analog front end and back end for microprocessors
(the Frame ASIC concept)
analog microelectronics
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
Internet: http://www.analogmicro.de
Phone:
Fax:
Email:
+49 (0)6131/91 073 – 0
+49 (0)6131/91 073 – 30
[email protected]
Mars 2006
20/21
Rev. 2.3
INDUSTRIAL VOLTAGE AMPLIFIER IC
AM401
DELIVERY
AM401 is available as the following packages:
•
•
•
•
16-pin DIL (samples, small series)
SO 16 (n): please see our website (data sheets: package.pdf)
SSOP 16: please see our website (data sheets: package.pdf)
Dice on 5” blue foil (on request)
PACKAGE DIMENSIONS
Please see our website (data sheets: package.pdf).
FURTHER READING
[1] The Frame ASIC concept: http://www.Frame-ASIC.de/
[2] The Analog Microelectronics GmbH website: http://www.analogmicro.de/
[3] Available also for the AM401: Application notes AN1013 on the Analog Microelectronics
website: http://www.analogmicro.de/
Analog Microelectronics reserves the right to make amendments to any dimensions, technical data or other information contained herein without further
notice.
analog microelectronics
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
Internet: http://www.analogmicro.de
Phone:
Fax:
Email:
+49 (0)6131/91 073 – 0
+49 (0)6131/91 073 – 30
[email protected]
Mars 2006
21/21
Rev. 2.3
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