ON NE5230 Low voltage operational amplifier Datasheet

NE5230, SA5230, SE5230
Low Voltage Operational
Amplifier
The NE5230 is a very low voltage operational amplifier that can
perform with a voltage supply as low as 1.8 V or as high as 15 V.
In addition, split or single supplies can be used, and the output will
swing to ground when applying the latter. There is a bias adjusting pin
which controls the supply current required by the device and thereby
controls its power consumption. If the part is operated at ±0.9 V
supply voltages, the current required is only 110 mA when the current
control pin is left open. Even with this low power consumption, the
device obtains a typical unity gain bandwidth of 250 kHz. When the
bias adjusting pin is connected to the negative supply, the unity gain
bandwidth is typically 600 kHz while the supply current is increased
to 600 mA. In this mode, the part will supply full power output beyond
the audio range.
The NE5230 also has a unique input stage that allows the
common−mode input range to go above the positive and below the
negative supply voltages by 250 mV. This provides for the largest
possible input voltages for low voltage applications. The part is also
internally−compensated to reduce external component count.
The NE5230 has a low input bias current of typically ±40 nA, and a
large open−loop gain of 125 dB. These two specifications are
beneficial when using the device in transducer applications. The large
open−loop gain gives very accurate signal processing because of the
large “excess” loop gain in a closed−loop system.
The output stage is a class AB type that can swing to within 100 mV
of the supply voltages for the largest dynamic range that is needed in
many applications. The NE5230 is ideal for portable audio equipment
and remote transducers because of its low power consumption, unity
gain bandwidth, and 30 nV/√Hz noise specification.
Features
•
•
•
•
•
•
Works Down to 1.8 V Supply Voltages
Adjustable Supply Current
Low Noise
Common−mode Includes Both Rails
VOUT Within 100 mV of Both Rails
These are Pb−Free Devices
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8
8
1
1
SOIC−8
D SUFFIX
CASE 751
PDIP−8
N SUFFIX
CASE 626
PIN CONNECTIONS
N, D Packages
NC
1
8
NC
−IN
2
7
VCC
+IN
3
6
OUTPUT
5
BIAS ADJ.
VEE
−
+
4
(Top View)
DEVICE MARKING INFORMATION
See general marking information in the device marking
section on page 16 of this data sheet.
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 16 of this data sheet.
Applications
•
•
•
•
•
•
Portable Precision Instruments
Remote Transducer Amplifier
Portable Audio Equipment
Rail−to−Rail Comparators
Half−wave Rectification without Diodes
Remote Temperature Transducer with 4.0 to 20 mA Output
Transmission
© Semiconductor Components Industries, LLC, 2010
August, 2010 − Rev. 5
1
Publication Order Number:
NE5230/D
NE5230, SA5230, SE5230
MAXIMUM RATINGS
Rating
Symbol
Value
Unit
VCC
18
V
Dual Supply Voltage
VS
±9
V
Input Voltage (Note 1)
VIN
±9 (18)
V
±VS
V
V
Single Supply Voltage
Differential Input Voltage (Note 1)
Common−Mode Voltage (Positive)
VCM
VCC + 0.5
Common−Mode Voltage (Negative)
VCM
VEE − 0.5
V
PD
500
mW
Power Dissipation (Note 2)
Thermal Resistance, Junction−to−Ambient
N Package
D Package
Operating Junction Temperature (Note 2)
RqJA
TJ
Operating Temperature Range
NE
SA
SE
TA
80 Output Short−Circuit Duration to Either Power Supply Pin (Notes 2 and 3)
130
182
150
0 to 70
−40 to 85
−40 to 125
°C/W
°C
°C
Indefinite
s
Storage Temperature
Tstg
−65 to 150
°C
Lead Soldering Temperature (10 sec max)
Tsld
230
°C
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. Can exceed the supply voltages when VS ≤ ±7.5 V (15 V).
2. The maximum operating junction temperature is 150°C. At elevated temperatures, devices must be derated according to the package thermal
resistance and device mounting conditions.
Derate above 25°C at the following rates:
N package at 7.7 mW/°C
D package at 5.5 mW/°C.
3. Momentary shorts to either supply are permitted in accordance to transient thermal impedance limitations determined by the package and
device mounting conditions.
RECOMMENDED OPERATING CONDITIONS
Characteristic
Value
Unit
1.8 to 15
V
Dual Supply Voltage
±0.9 to ±7.5
V
Common−Mode Voltage (Positive)
VCC + 0.25
V
Single Supply Voltage
Common−Mode Voltage (Negative)
Temperature
NE Grade
SA Grade
SE Grade
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2
VEE − 0.25
V
0 to +70
−40 to +85
−40 to +125
°C
NE5230, SA5230, SE5230
DC AND AC ELECTRICAL CHARACTERISTIC Unless otherwise specified, ±0.9V ≤ Vs ≤ ±7.5 V or equivalent single supply,
RL = 10 kW, full input common−mode range, over full operating temperature range.
Characteristic
Symbol
Test Conditions
Bias
TA = 25°C
TA = Tlow to Thigh
Min
Typ
Max
Unit
Any
0.4
3.0
mV
Any
3.0
4.0
Any
2.0
5.0
mV/°C
High
3.0
50
nA
Low
3.0
30
NE5230, SA5230
Offset Voltage
VOS
Drift
VOS
Offset Current
IOS
TA = 25°C
TA = Tlow to Thigh
Drift
Bias Current
0.5
Low
0.3
1.4
IB
High
40
150
Low
20
TA = 25°C
IS
TA = 25°C
VS = ±0.9 V
TA = Tlow to Thigh
TA = 25°C
VS = ±7.5 V
TA = Tlow to Thigh
Common−Mode Input Range
Common−Mode Rejection Ratio
VCM
PSRR
Source
IL
150
High
2.0
4.0
Low
2.0
4.0
Low
110
160
High
600
750
Low
High
320
550
High
1100
1600
Low
mA
mA
600
High
1700
V−
RS = 10 kW; VCM = ±7.5 V;
TA = 25°C
Any
85
RS = 10 kW; VCM = ±7.5 V;
TA = Tlow to Thigh
Any
80
High
Low
High
75
V+
− 0.25
+ 0.25
V
V+
95
dB
90
105
dB
85
95
Low
80
VS = ±0.9 V; TA = 25°C
High
4.0
5.0
6
Sink
VS = ±0.9 V; TA = 25°C
High
Source
VS = ±7.5 V; TA = 25°C
High
16
Sink
VS = ±7.5 V; TA = 25°C
High
32
Source
VS = ±0.9 V; TA = Tlow to Thigh
Any
1.0
5
Sink
VS = ±0.9 V; TA = Tlow to Thigh
Any
2.0
6
Source
VS = ±7.5 V; TA = Tlow to Thigh
Any
4.0
10
Sink
VS = ±7.5 V; TA = Tlow to Thigh
Any
5.0
15
For NE5230 devices, Tlow = 0°C and Thigh = +70°C. For SA5230 devices, Tlow = −40°C and Thigh = +85°C.
3
nA/°C
800
Low
V−
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nA
250
Any
VOS v 6 mV, TA = Tlow to Thigh
Load Current
Low
Any
TA = 25°C
nA/°C
60
200
VOS ≤ 6 mV, TA = 25°C
CMRR
1.4
High
VOS ≤ 6 mV, TA = Tlow to Thigh
VS = ±7.5 V
Power Supply Rejection Ratio
60
High
IB
Supply Current
100
Low
IOS
TA = Tlow to Thigh
Drift
High
7
mA
NE5230, SA5230, SE5230
DC AND AC ELECTRICAL CHARACTERISTIC Unless otherwise specified, ±0.9V ≤ Vs ≤ ±7.5 V or equivalent single supply,
RL = 10 kW, full input common−mode range, over full operating temperature range.
Characteristic
Symbol
Test Conditions
Bias
TA = 25°C
TA = Tlow to Thigh
Min
Typ
Max
Unit
Any
0.4
3.0
mV
Any
3.0
4.0
Any
2.0
5.0
mV/°C
High
3.0
50
nA
Low
3.0
30
SE5230
Offset Voltage
VOS
Drift
VOS
Offset Current
IOS
TA = 25°C
TA = Tlow to Thigh
Drift
Bias Current
Low
0.3
1.4
IB
High
40
150
Low
20
60
TA = 25°C
TA = 25°C
VS = ±0.9 V
TA = Tlow to Thigh
TA = 25°C
VS = ±7.5 V
TA = Tlow to Thigh
Common−Mode Rejection Ratio
VCM
High
300
Low
300
High
2.0
4.0
Low
2.0
4.0
Low
110
160
High
600
750
Low
High
320
550
High
1100
1600
Low
600
High
1700
V+ + 0.25
VOS ≤ 20 mV, TA = Tlow to Thigh
Any
V−
V+
RS = 10 kW; VCM = ±7.5 V;
TA = 25°C
Any
85
RS = 10 kW; VCM = ±7.5 V;
TA = Tlow to Thigh
Any
80
High
PSRR
TA = 25°C
dB
Low
85
95
High
75
80
6
Sink
VS = ±0.9 V; TA = 25°C
High
5.0
7
Source
VS = ±7.5 V; TA = 25°C
High
16
Sink
VS = ±7.5 V; TA = 25°C
High
32
Source
VS = ±0.9 V; TA = Tlow to Thigh
Any
1.0
5
Sink
VS = ±0.9 V; TA = Tlow to Thigh
Any
2.0
6
Source
VS = ±7.5 V; TA = Tlow to Thigh
Any
4.0
10
Sink
VS = ±7.5 V; TA = Tlow to Thigh
Any
5.0
15
4
V
105
4.0
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mA
90
Low
For SE5230 devices, Tlow = −40°C and Thigh = +125°C.
mA
dB
High
IL
nA/°C
95
VS = ±0.9 V; TA = 25°C
Source
nA
850
Low
V− − 0.25
CMRR
nA/°C
275
Any
TA = Tlow to Thigh
Load Current
1.4
VOS ≤ 6 mV, TA = 25°C
VS = ±7.5 V
Power Supply Rejection Ratio
60
0.5
IS
Common−Mode Input Range
Low
High
IB
Supply Current
100
IOS
TA = Tlow to Thigh
Drift
High
mA
NE5230, SA5230, SE5230
DC AND AC ELECTRICAL CHARACTERISTIC Unless otherwise specified, ±0.9V ≤ Vs ≤ ±7.5 V or equivalent single supply,
RL = 10 kW, full input common−mode range, over full operating temperature range.
Characteristic
Symbol
Test Conditions
Bias
Min
Typ
High
120
2000
Low
60
750
High
100
Max
Unit
NE5230, SA5230, SE5230
Large−Signal Open−Loop Gain
AVOL
VS = ±7.5 V
RL = 10 kW; TA = 25°C
TA = Tlow to Thigh
Output Voltage Swing
VOUT
VS = ±0.9 V
VS = ±7.5 V
Slew Rate
SR
Inverting Unity Gain Bandwidth
BW
Phase Margin
qM
Settling Time
tS
Input Noise
VINN
Total Harmonic Distortion
THD
Low
50
TA = 25°C +SW
Any
750
800
800
TA = 25°C −SW
Any
750
TA = Tlow to Thigh; +SW
Any
700
TA = Tlow to Thigh; −SW
Any
700
TA = 25°C +SW
Any
7.30
7.35
TA = 25°C −SW
Any
−7.32
−7.35
TA = Tlow to Thigh; +SW
Any
7.25
7.30
TA = Tlow to Thigh; −SW
Any
−7.30
−7.35
TA = 25°C
CL = 100 pF; TA = 25°C
CL = 100 pF; TA = 25°C
CL = 100 pF, 0.1%
RS = 0 W; f = 1.0 kHz
High
0.25
V
V/ms
Low
0.09
V/ms
0.6
MHz
Low
0.25
MHz
Any
70
°
High
2.0
ms
Low
5.0
ms
High
30
nV/√Hz
nV/√Hz
Low
60
High
0.003
VS = ±0.9 V
AV = 1, VIN = 500 mV; f = 1.0 kHz
High
0.002
For NE5230 devices, Tlow = 0°C and Thigh = +70°C. For SA5230 devices, Tlow = −40°C and Thigh = +85°C.
For SE5230 devices, Tlow = −40°C and Thigh = +125°C.
5
mV
High
VS = ±7.5 V
AV = 1; VIN = 500 mV; f = 1.0 kHz
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V/mV
%
%
NE5230, SA5230, SE5230
THEORY OF OPERATION
voltage moves from the range where only the NPN pair was
Operational amplifiers which are able to function at
operating to where both of the input pairs were operating, the
minimum supply voltages should have input and output
effective transconductance would change by a factor of two.
stage swings capable of reaching both supply voltages
Frequency compensation for the ranges where one input pair
within a few millivolts in order to achieve ease of quiescent
was operating would, of course, not be optimal for the range
biasing and to have maximum input/output signal handling
where both pairs were operating. Secondly, fast changes in
capability. The input stage of the NE5230 has a
the common−mode voltage would abruptly saturate and
common−mode voltage range that not only includes the
restore the emitter current sources, causing transient
entire supply voltage range, but also allows either supply to
distortion. These problems were overcome by assuring that
be exceeded by 250 mV without increasing the input offset
only the input transistor pair which is able to function
voltage by more than 6.0 mV. This is unequalled by any
properly is active. The NPN pair is normally activated by the
other operational amplifier today.
current source IB1 through Q5 and the current mirror Q6 and
In order to accomplish the feat of rail−to−rail input
Q7, assuming the PNP pair is non−conducting. When the
common−mode range, two emitter−coupled differential
common−mode input voltage passes below the reference
pairs are placed in parallel so that the common−mode
voltage, VB1 − 0.8 V at the base of Q5, the emitter current is
voltage of one can reach the positive supply rail and the other
gradually steered toward the PNP pair, away from the NPN
can reach the negative supply rail. The simplified schematic
pair. The transfer of the emitter currents between the
of Figure 1 shows how the complementary emitter−coupler
complementary input pairs occurs in a voltage range of
transistors are configured to form the basic input stage cell.
about 120 mV around the reference voltage VB1. In this way
Common−mode input signal voltages in the range from
the sum of the emitter currents for each of the NPN and PNP
0.8 V above VEE to VCC are handled completely by the NPN
transistor pairs is kept constant; this ensures that the
pair, Q3 and Q4, while common−mode input signal voltages
transconductance of the parallel combination will be
in the range of VEE to 0.8 V above VEE are processed only
constant, since the transconductance of bipolar transistors is
by the PNP pair, Q1 and Q2. The intermediate range of input
proportional to their emitter currents.
voltages requires that both the NPN and PNP pairs are
An essential requirement of this kind of input stage is to
operating. The collector currents of the input transistors are
minimize the changes in input offset voltage between that of
summed by the current combiner circuit composed of
the NPN and PNP transistor pair which occurs when the
transistors Q8 through Q11 into one output current.
input common−mode voltage crosses the internal reference
Transistor Q8 is connected as a diode to ensure that the
voltage, VB1. Careful circuit layout with a cross−coupled
outputs of Q2 and Q4 are properly subtracted from those of
quad for each input pair has yielded a typical input offset
Q1 and Q3.
voltage of less than 0.3 mV and a change in the input offset
The input stage was designed to overcome two important
voltage of less than 0.1 mV.
problems for rail−to−rail capability. As the common−mode
Input Stage
VCC
R11
R10
VIN−
Q3
Q2
Q1
Q4
VIN+
Q6
IOUT
Q9
Q8
Q5
+
V Vb1
Q11
Q10
Ib1
Q7
+
V Vb2
R8
R9
VEE
Figure 1. Input Stage
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NE5230, SA5230, SE5230
Output Stage
combined voltages across diodes D1 and D2 are
proportional to the logarithm of the square of the reference
current IB1. When the diode characteristics and
temperatures of the pairs Q1, D1 and Q3, Q2 are equal, the
relation IOP × ION − IB1 × IB1 is satisfied.
Separating the functions of biasing and driving prevents
the driving signals from becoming delayed by the biasing
circuit. The output Darlington transistors are directly
accessible for in−phase driving signals on the bases of Q5
and Q2. This is very important for simple high−frequency
compensation. The output transistors can be high−frequency
compensated by Miller capacitors CM1A and CM1B
connected from the collectors to the bases of the output
Darlington transistors.
A general−purpose op amp of this type must have enough
open−loop gain for applications when the output is driving
a low resistance load. The NE5230 accomplishes this by
inserting an intermediate common−emitter stage between
the input and output stages. The three stages provide a very
large gain, but the op amp now has three natural dominant
poles − one at the output of each common−emitter stage.
Frequency compensation is implemented with a simple
scheme of nested, pole−splitting Miller integrators. The
Miller capacitors CM1A and CM1B are the first part of the
nested structure, and provide compensation for the output
and intermediate stages. A second pair of Miller integrators
provide pole−splitting compensation for the pole from the
input stage and the pole resulting from the compensated
combination of poles from the intermediate and output
stages. The result is a stable, internally−compensated op
amp with a phase margin of 70°.
Processing output voltage swings that nominally reach to
less than 100 mV of either supply voltage can only be
achieved by a pair of complementary common−emitter
connected transistors. Normally, such a configuration
causes complex feed−forward signal paths that develop by
combining biasing and driving which can be found in
previous low supply voltage designs. The unique output
stage of the NE5230 separates the functions of driving and
biasing, as shown in the simplified schematic of Figure 2 and
has the advantage of a shorter signal path which leads to
increasing the effective bandwidth.
This output stage consists of two parts: the Darlington
output transistors and the class AB control regulator. The
output transistor Q3 connected with the Darlington
transistors Q4 and Q5 can source up to 10 mA to an output
load. The output of NPN Darlington connected transistors
Q1 and Q2 together are able to sink an output current of
10 mA. Accurate and efficient class AB control is necessary
to insure that none of the output transistors are ever
completely cut off. This is accomplished by the differential
amplifier (formed by Q8 and Q9) which controls the biasing
of the output transistors. The differential amplifier compares
the summed voltages across two diodes, D1 and D2, at the
base of Q8 with the summed voltages across the
base−emitter diodes of the output transistors Q1 and Q3. The
base−emitter voltage of Q3 is converted into a current by Q6
and R6 and reconverted into a voltage across the
base−emitter diode of Q7 and R7. The summed voltage
across the base−emitter diodes of the output transistors Q3
and Q1 is proportional to the logarithm of the product of the
push and pull currents IOP and ION, respectively. The
VCC
R6
Ib1
Ib2
Ib3
Q3
Q6
Vb5
Q5
IOP
Q4
CM1B
VOUT
CM1A
Q2
Vb2
Q8
ION
Q9
R7
D1
Ib4
Q7
Q1
Ib5
D2
VEE
Figure 2. Output Stage
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NE5230, SA5230, SE5230
THERMAL CONSIDERATIONS
When using the NE5230, the internal power dissipation
capabilities of each package should be considered.
ON Semiconductor does not recommend operation at die
temperatures above 110°C in the SO package because of its
inherently smaller package mass. Die temperatures of
150°C can be tolerated in all the other packages. With this
in mind, the following equation can be used to estimate the
die temperature:
Tj + Tamb ) (PD
qJA)
negative supply. The resistor can be selected between 1.0 W
to 100 kW to provide any required supply current over the
indicated range. In addition, a small varying voltage on the
bias current control pin could be used for such exotic things
as changing the gain−bandwidth for voltage controlled low
pass filters or amplitude modulation. Furthermore, control
over the slew rate and the rise time of the amplifier can be
obtained in the same manner. This control over the slew rate
also changes the settling time and overshoot in pulse
response applications. The settling time to 0.1% changes
from 5.0 ms at low bias to 2.0 ms at high bias. The supply
current control can also be utilized for wave−shaping
applications such as for pulse or triangular waveforms. The
gain−bandwidth can be varied from between 250 kHz at low
bias to 600 kHz at high bias current. The slew rate range is
0.08 V/ms at low bias and 0.25 V/ms at high bias.
(eq. 1)
POWER SUPPLY CURRENT (mA)
Where
Tamb = Ambient Temperature
Tj = Die Temperature
PD = Power Dissipation
= (ICC x VCC)
qJA = Package Thermal Resistance
= 270°C/W for SO−8 in PC Board Mounting
See the packaging section for information regarding other
methods of mounting.
qJA − 100°C/W for the plastic DIP.
The maximum supply voltage for the part is 15 V and the
typical supply current is 1.1 mA (1.6 mA max). For
operation at supply voltages other than the maximum, see
the data sheet for ICC versus VCC curves. The supply current
is somewhat proportional to temperature and varies no more
than 100 mA between 25°C and either temperature extreme.
Operation at higher junction temperatures than that
recommended is possible but will result in lower Mean Time
Between Failures (MTBF). This should be considered
before operating beyond recommended die temperature
because of the overall reliability degradation.
800
700
600
500
400
300
200
100
100
200
300
400 500 600700
UNITY GAIN BANDWIDTH (kHz)
Figure 3. Unity Gain Bandwidth vs. Power Supply
Current for VCC = ±0.9 V
DESIGN TECHNIQUES AND APPLICATIONS
The NE5230 is a very user−friendly amplifier for an
engineer to design into any type of system. The supply
current adjust pin (Pin 5) can be left open or tied through a
pot or fixed resistor to the most negative supply (i.e., ground
for single supply or to the negative supply for split supplies).
The minimum supply current is achieved by leaving this pin
open. In this state it will also decrease the bandwidth and
slew rate. When tied directly to the most negative supply, the
device has full bandwidth, slew rate and ICC. The
programming of the current−control pin depends on the
trade−offs which can be made in the designer’s application.
The graphs in Figures 3 and 4 will help by showing
bandwidth versus ICC. As can be seen, the supply current can
be varied anywhere over the range of 100 mA to 600 mA for
a supply voltage of 1.8 V. An external resistor can be
inserted between the current control pin and the most
1.4
ICC CURRENT (mA)
1.2
VCC − 15V
1.0
VCC − 9V
0.8
VCC − 6V
VCC − 3V
0.6
VCC − 2V
0.4
TA − 25°C
VCC − 12V
VCC − 1.8V
0.2
0.0 0
10
101
102
103
104
105
RADJ (W)
Figure 4. ICC Current vs. Bias Current Adjusting
Resistor for Several Supply Voltages
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8
NE5230, SA5230, SE5230
swing less than 100 mV of either supply voltage. Many
competitive parts will show severe clipping caused by input
common−mode limitations. The NE5230 in this
configuration offers more freedom for quiescent biasing of
the inputs close to the positive supply rail where similar op
amps would not allow signal processing.
There are not as many considerations when designing
with the NE5230 as with other devices. Since the NE5230
is internally−compensated and has a unity gain−bandwidth
of 600 kHz, board layout is not so stringent as for very high
frequency devices such as the NE5205. The output
capability of the NE5230 allows it to drive relatively high
capacitive loads and small resistive loads. The power supply
pins should be decoupled with a low−pass RC network as
close to the supply pins as possible to eliminate 60 Hz and
other external power line noise, although the power supply
rejection ratio (PSRR) for the part is very high. The pinout
for the NE5230 is the same as the standard single op amp
pinout with the exception of the bias current adjusting pin.
The full output power bandwidth range for VCC equals
2.0 V, is above 40 kHz for the maximum bias current setting
and greater than 10 kHz at the minimum bias current setting.
If extremely low signal distortion (<0.05%) is required at
low supply voltages, exclude the common−mode crossover
point (VB1) from the common−mode signal range. This can
be accomplished by proper bias selection or by using an
inverting amplifier configuration.
Most single supply designs necessitate that the inputs to
the op amp be biased between VCC and ground. This is to
assure that the input signal swing is within the working
common−mode range of the amplifier. This leads to another
helpful and unique property of the NE5230 that other CMOS
and bipolar low voltage parts cannot achieve. It is the simple
fact that the input common−mode voltage can go beyond
either the positive or negative supply voltages. This benefit
is made very clear in a non−inverting voltage−follower
configuration. This is shown in Figure 5 where the input sine
wave allows an undistorted output sine wave which will
V+
V+
+
−
V−
V−
V+
NE5230
V−
V+
OTHER
PARTS
V−
Figure 5. In a non−inverting voltage−follower configuration, the NE5230 will give full rail−to−rail swing.
Other low voltage amplifiers will not because they are limited by their input common−mode
range and output swing capability.
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9
NE5230, SA5230, SE5230
REMOTE TRANSDUCER WITH CURRENT
TRANSMISSION
There are many ways to transmit information along two
wires, but current transmission is the most beneficial when
the sensing of remote signals is the aim. It is further
enhanced in the form of 4.0 to 20 mA information which is
used in many control−type systems. This method of
transmission provides immunity from line voltage drops,
large load resistance variations, and voltage noise pickup.
The zero reference of 4mA not only can show if there is a
break in the line when no current is flowing, but also can
power the transducer at the remote location. Usually the
transducer itself is not equipped to provide for the current
transmission. The unique features of the NE5230 can
provide high output current capability coupled with low
power consumption. It can be remotely connected to the
transducer to create a current loop with minimal external
components. The circuits for this are shown in Figures 6
and 7. Here, the part is configured as a voltage−to−current,
or transconductance amplifier. This is a novel circuit that
takes advantage of the NE5230’s large open−loop gain. In
AC applications, the load current will decrease as the
open−loop gain rolls off in magnitude. The low offset
voltage and current sinking capabilities of the NE5230 must
also be considered in this application.
The NE5230 circuit shown in Figure 6 is a pseudo
transistor configuration. The inverting input is equivalent to
the “base,” the point where VEE and the non−inverting input
meet is the “emitter,” and the connection after the output
diode meets the VCC pin is the collector. The output diode
is essential to keep the output from saturating in this
configuration. From here it can be seen that the base and
emitter form a voltage−follower and the voltage present at
RC must equal the input voltage present at the inverting
input. Also, the emitter and collector form a
current−follower and the current flowing through RC is
equivalent to the current through RL and the amplifier. This
sets up the current loop. Therefore, the following equation
can be formulated for the working current transmission line.
The load current is:
V
IL + IN
RC
Where VCC min is the worst−case power supply voltage
(approximately 1.8 V) that will still keep the part
operational. As an example, when using a 15 V remote
power supply, a current sensing resistor of 1.0 W, and an
input voltage (VIN) of 20 mV, the output current (IL) is
20 mA. Furthermore, a load resistance of zero to
approximately 650 W can be inserted in the loop without any
change in current when the bias current−control pin is tied
to the negative supply pin. The voltage drop across the load
and line resistance will not affect the NE5230 because it will
operate down to 1.8 V. With a 15 V remote supply, the
voltage available at the amplifier is still enough to power it
with the maximum 20 mA output into the 650 W load.
3
2
T
R
A
N
S
D
U
C
E
R
− 4
IOUT
V
6
+REMOTE
POWER
− SUPPLY
5
VEE
RL
VIN
RC
NOTES:
1. IOUT = VIN/RC
* 1.8V * V INMAX
V
2. RL MAX ≈ REMOTE
I OUT
For RC = 1.0 W
I OUT
V IN
4mA
4mV
20mA 20mV
Figure 6. The NE5230 as a Remote Transducer
Transconductance Amp with 4.0 − 20 mA Current
Transmission Output Capability
+
RC
VIN
(eq. 2)
−
3
+
7
VCC
− 4
+
−
6
NE5230
2
VCC
5
VEE
+ IOUT
RL
Figure 7. The Same Type of Circuit as Figure 6, but
for Sourcing Current to the Load
ƪVremote supply * VCC min * VIN maxƫ
IL
VCC
NE5230
and proportional to the input voltage for a set RC. Also, the
current is constant no matter what load resistance is used
while within the operating bandwidth range of the op amp.
When the NE5230’s supply voltage falls past a certain point,
the current cannot remain constant. This is the “voltage
compliance” and is very good for this application because of
the near rail output voltage. The equation that determines the
voltage compliance as well as the largest possible load
resistor for the NE5230 is as follows:
RLmax +
+
7
(eq. 3)
http://onsemi.com
10
NE5230, SA5230, SE5230
ground to convert the current back to voltage. Again, the
current sensing resistor will set up the transconductance and
the part will receive power from the line.
What this means is that several instruments, such as a chart
recorder, a meter, or a controller, as well as a long cable, can
be connected in series on the loop and still obtain accurate
readings if the total resistance does not exceed 650 W.
Furthermore, any variation of resistance in this range will
not change the output current.
Any voltage output type transducer can be used, but one
that does not need external DC voltage or current excitation
to limit the maximum possible load resistance is preferable.
Even this problem can be surmounted if the supply power
needed by the transducer is compatible with the NE5230.
The power goes up the line to the transducer and amplifier
while the transducer signal is sent back via the current output
of the NE5230 transconductance configuration.
The voltage range on the input can be changed for
transducers that produce a large output by simply increasing
the current sense resistor to get the corresponding 4.0 to
20 mA output current. If a very long line is used which
causes high line resistance, a current repeater could be
inserted into the line. The same configuration of Figure 7 can
be used with exception of a resistor across the input and line
3
+
7
VCC
−
V
4 EE
10W
IOUT
V
6
NE5230
2
TEMPERATURE TRANSDUCER
A variation on the previous circuit makes use of the supply
current control pin. The voltage present at this pin is
proportional to absolute temperature (PTAT) because it is
produced by the amplifier bias current through an internal
resistor divider in a PTAT cell. If the control pin is connected
to the input pin, the NE5230 itself can be used as a
temperature transducer. If the center tap of a resistive pot is
connected to the control pin with one side to ground and the
other to the inverting input, the voltage can be changed to
give different temperature versus output current conditions
(Figure 8). For additional control, the output current is still
proportional to the input voltage differential divided by the
current sense resistor.
When using the NE5230 as a temperature transducer, the
thermal considerations in the previous section must be kept
in mind.
+REMOTE
POWER
− SUPPLY
5
RL
200
RC
NOTES:
1. IOUT = VIN/RC
* 1.8V * V INMAX
V
2. RL MAX ≈ REMOTE
I OUT
For RC = 1W
I OUT
V IN
4mA
4mV
20mA 20mV
Figure 8. NE5230 remote temperature transducer utilizing 4.0 − 20 mA current transmission. This application
shows the use of the accessibility of the PTAT cell in the device to make the part, itself, a transducer.
http://onsemi.com
11
NE5230, SA5230, SE5230
HALF−WAVE RECTIFIER WITH
RAIL−TO−GROUND OUTPUT SWING
Since the NE5230 input common−mode range includes
both positive and negative supply rails and the output can
also swing to either supply, achieving half−wave rectifier
functions in either direction becomes a simple task. All that
is needed are two external resistors; there is no need for
diodes or matched resistors. Moreover, it can have either
positive− or negative−going outputs, depending on the way
the bias is arranged. In Figure 9, the circuit is biased to
ground, while circuit (Figure 10) is biased to the positive
supply. This rather unusual biasing does not cause any
problems with the NE5230 because of the unique internal
saturation detectors incorporated into the part to keep the
PNP and NPN output transistors out of “hard” saturation. It
is therefore relatively quick to recover from a saturated
output condition. Furthermore, the device does not have
parasitic current draw when the output is biased to either rail.
This makes it possible to bias the NE5230 into “saturation”
and obtain half−wave rectification with good recovery. The
simplicity of biasing and the rail−to−ground half−sine wave
swing are unique to this device. The circuit gain can be
changed by the standard op amp gain equations for an
inverting configuration.
It can be seen in these configurations that the op amp
cannot respond to one−half of the incoming waveform. It
cannot respond because the waveform forces the amplifier
to swing the output beyond either ground or the positive
supply rail, depending on the biasing, and, also, the output
cannot disengage during this half cycle. During the other
half cycle, however, the amplifier achieves a half−wave that
can have a peak equal to the total supply voltage. The
photographs in Figure 11 show the effect of the different
biasing schemes, as well as the wide bandwidth (it works
over the full audio range), that the NE5230 can achieve in
this configuration.
Half−Wave Rectifier With Positive−Going Output Swings
10W
VIN
10W
VCC
2
7
−
6
3
+
4
VOUT
VCC
5
O
t
Figure 9. Rail−to−Ground Output Swing Referenced to Ground
VCC
3
10W
2
VIN
7
+
−
6
4
VOUT
5
VCC
10W
VCC
t
Figure 10. Negative−Going Output Referenced to VCC
http://onsemi.com
12
NE5230, SA5230, SE5230
500 mV/Div 200mS /Div
Biased to Ground
500 mV/Div 20 mS/Div
Biased to Ground
500 mV/Div 20 mS/Div
Biased to Positive Rail
Figure 11. Performance Waveforms for the Circuits in Figures 9 and 10.
Good response is shown at 1.0 and 10 kHz for both circuits under full swing with a 2.0 V supply.
http://onsemi.com
13
NE5230, SA5230, SE5230
waveform can be referenced to the supply or ground,
depending on the half−wave configuration. Again, no
diodes are needed to achieve the rectification.
This circuit could be used in conjunction with the remote
transducer to convert a received AC output signal into a DC
level at the full−wave output for meters or chart recorders
that need DC levels.
By adding another NE5230 in an inverting summer
configuration at the output of the half−wave rectifier, a
full−wave can be realized. The values for the input and
feedback resistors must be chosen so that each peak will
have equal amplitudes. A table for calculating values is
included in Figure 12. The summing network combines the
input signal at the half−wave and adds it to double the
half−wave’s output, resulting in the full−wave. The output
500mV
500mV
520ms
INPUT
HALF-WAVE
OUTPUT
+VIN
FULL-WAVE
OUTPUT
a
500mV
b
−VIN
R3
3
+VIN
−VIN
2 −
b
NOTES:
R2 = 2 R1
R4 = R5 = R3
+VB will vary output reference.
For single supply operation VEE
can be grounded on A2.
VCC
7
+
6
A1
R1
a
R5
4
R2
R4
2
5
VEE
3
+VB
−
6
A2
+
+VIN
7
4
5
+VB
a
b
FULL-WAVE
VEE
0
2a
−2VIN
HALF-WAVE
Figure 12. Adding an Inverting Summer to the Input and Output of the Half−Wave will Result in Full−Wave
http://onsemi.com
14
NE5230, SA5230, SE5230
REFERENCES
1. Johan H. Huijsing, Multi−stage Amplifier with
Capacitive Nesting for Frequency Compensation,
U.S. Patent Application Serial No. 602.234, filed
April 19, 1984.
2. Bob Blauschild, Differential Amplifier with
Rail−to−Rail Capability, U.S. Patent Application
Serial No. 525.181, filed August 23, 1983.
3. Operational Amplifiers − Characteristics and
Applications, Robert G. Irvine, Prentice−Hall, Inc.,
Englewood Cliffs, NJ 07632, 1981.
4. Transducer Interface Handbook − A Guide to
Analog Signal Conditioning, Edited by Daniel H.
Sheingold, Analog Devices, Inc., Norwood, MA
02062, 1981.
CONCLUSION
The NE5230 is a versatile op amp in its own right. The part
was designed to give low voltage and low power operation
without the limitations of previously available amplifiers
that had a multitude of problems. The previous application
examples are unique to this amplifier and save the user
money by excluding various passive components that would
have been needed if not for the NE5230’s special input and
output stages.
The NE5230 has a combination of novel specifications
which allows the designer to implement it easily into
existing low−supply voltage designs and to enhance their
performance. It also offers the engineer the freedom to
achieve greater amplifier system design goals. The low input
referenced noise voltage eases the restrictions on designs
where S/N ratios are important. The wide full−power
bandwidth and output load handling capability allow it to fit
into portable audio applications. The truly ample open−loop
gain and low power consumption easily lend themselves to
the requirements of remote transducer applications. The
low, untrimmed typical offset voltage and low offset
currents help to reduce errors in signal processing designs.
The amplifier is well isolated from changes on the supply
lines by its typical power supply rejection ratio of 105 dB.
http://onsemi.com
15
NE5230, SA5230, SE5230
MARKING DIAGRAMS
8
1
8
N5230
ALYW
G
1
8
S5230
ALYW
G
1
NE5230N
AWL
YYWWG
S5230
ALYWE
G
SOIC−8
D SUFFIX
CASE 751
SA5230N
AWL
YYWWG
PDIP−8
N SUFFIX
CASE 626
A
WL, L
YY, Y
WW, W
G or G
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
ORDERING INFORMATION
Description
Temperature Range
Shipping†
NE5230DG
8−Pin Plastic Small Outline (SO−8) Package
(Pb−Free)
0°C to +70°C
98 Units / Rail
NE5230DR2G
8−Pin Plastic Small Outline (SO−8) Package
(Pb−Free)
0°C to +70°C
2500 / Tape & Reel
NE5230NG
8−Pin Plastic Dual In−Line Package (PDIP−8)
(Pb−Free)
0°C to +70°C
50 Units / Rail
SA5230DG
8−Pin Plastic Small Outline (SO−8) Package
(Pb−Free)
−40°C to +85°C
98 Units / Rail
SA5230DR2G
8−Pin Plastic Small Outline (SO−8) Package
(Pb−Free)
−40°C to +85°C
2500 / Tape & Reel
SA5230NG
8−Pin Plastic Dual In−Line Package (PDIP−8)
(Pb−Free)
−40°C to +85°C
50 Units / Rail
SE5230DG
8−Pin Plastic Small Outline (SO−8) Package
(Pb−Free)
−40°C to +125°C
98 Units / Rail
SE5230DR2G
8−Pin Plastic Small Outline (SO−8) Package
(Pb−Free)
−40°C to +125°C
2500 / Tape & Reel
Device
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
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16
NE5230, SA5230, SE5230
PACKAGE DIMENSIONS
PDIP−8
CASE 626−05
ISSUE M
D
A
D1
E
8
5
E1
1
4
NOTE 5
F
c
E2
END VIEW
TOP VIEW
NOTE 3
e/2
A
L
A1
C
SEATING
PLANE
E3
e
8X
SIDE VIEW
b
0.010
M
C A
END VIEW
http://onsemi.com
17
NOTES:
1. DIMENSIONING AND TOLERANCING PER ASME
Y14.5M, 1994.
2. CONTROLLING DIMENSION: INCHES.
3. DIMENSION E IS MEASURED WITH THE LEADS RESTRAINED PARALLEL AT WIDTH E2.
4. DIMENSION E1 DOES NOT INCLUDE MOLD FLASH.
5. ROUNDED CORNERS OPTIONAL.
DIM
A
A1
b
C
D
D1
E
E1
E2
E3
e
L
INCHES
NOM
MAX
−−−− 0.210
−−−− −−−−
0.018 0.022
0.010 0.014
0.365 0.400
−−−− −−−−
0.310 0.325
0.250 0.280
0.300 BSC
−−−−
−−−− 0.430
0.100 BSC
0.115 0.130 0.150
MIN
−−−−
0.015
0.014
0.008
0.355
0.005
0.300
0.240
MILLIMETERS
MIN
NOM
MAX
−−−−
−−−−
5.33
0.38
−−−− −−−−
0.35
0.46
0.56
0.20
0.25
0.36
9.02
9.27 10.02
0.13
−−−− −−−−
7.62
7.87
8.26
6.10
6.35
7.11
7.62 BSC
−−−−
−−−− 10.92
2.54 BSC
2.92
3.30
3.81
NE5230, SA5230, SE5230
PACKAGE DIMENSIONS
SOIC−8 NB
CASE 751−07
ISSUE AJ
−X−
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DIMENSION A AND B DO NOT INCLUDE
MOLD PROTRUSION.
4. MAXIMUM MOLD PROTRUSION 0.15 (0.006)
PER SIDE.
5. DIMENSION D DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR
PROTRUSION SHALL BE 0.127 (0.005) TOTAL
IN EXCESS OF THE D DIMENSION AT
MAXIMUM MATERIAL CONDITION.
6. 751−01 THRU 751−06 ARE OBSOLETE. NEW
STANDARD IS 751−07.
A
8
5
S
B
0.25 (0.010)
M
Y
M
1
4
−Y−
K
G
C
N
DIM
A
B
C
D
G
H
J
K
M
N
S
X 45 _
SEATING
PLANE
−Z−
0.10 (0.004)
H
D
0.25 (0.010)
M
Z Y
S
X
M
J
S
MILLIMETERS
MIN
MAX
4.80
5.00
3.80
4.00
1.35
1.75
0.33
0.51
1.27 BSC
0.10
0.25
0.19
0.25
0.40
1.27
0_
8_
0.25
0.50
5.80
6.20
INCHES
MIN
MAX
0.189
0.197
0.150
0.157
0.053
0.069
0.013
0.020
0.050 BSC
0.004
0.010
0.007
0.010
0.016
0.050
0 _
8 _
0.010
0.020
0.228
0.244
SOLDERING FOOTPRINT*
1.52
0.060
7.0
0.275
4.0
0.155
0.6
0.024
1.270
0.050
SCALE 6:1
mm Ǔ
ǒinches
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer
purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates,
and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal
Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
PUBLICATION ORDERING INFORMATION
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Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada
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18
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For additional information, please contact your local
Sales Representative
NE5230/D