OP495GSZ [ADI]
Dual/Quad Rail-to-Rail Operational Amplifiers; 双/四路轨到轨运算放大器
| 型号： | OP495GSZ |
| 厂家： | 
ADI |
| 描述： | Dual/Quad Rail-to-Rail Operational Amplifiers |
| 文件： | 总16页 (文件大小：397K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Dual/Quad Rail-to-Rail
Operational Amplifiers
OP295/OP495
PIN CONFIGURATIONS
FEATURES
Rail-to-rail output swing
Single-supply operation: 3 V to 36 V
Low offset voltage: 300 μV
Gain bandwidth product: 75 kHz
High open-loop gain: 1000 V/mV
Unity-gain stable
OUT A
–IN A
+IN A
V–
1
2
3
4
8
7
6
5
V+
OP295
OUT B
–IN B
+IN B
TOP VIEW
(Not to Scale)
Figure 1. 8-Lead Narrow-Body SOIC_N
(S Suffix)
Low supply current/per amplifier: 150 μA maximum
OUT A
–IN A
+IN A
V–
1
2
3
4
8
7
6
5
V+
OP295
APPLICATIONS
Battery-operated instrumentation
Servo amplifiers
OUT B
–IN B
+IN B
Actuator drives
Sensor conditioners
Power supply control
Figure 2. 8-Lead PDIP
(P Suffix)
OUT A
–IN A
+IN A
V+
1
2
3
4
5
6
7
14 OUT D
13 –IN D
12 +IN D
11 V–
GENERAL DESCRIPTION
Rail-to-rail output swing combined with dc accuracy are the
key features of the OP495 quad and OP295 dual CBCMOS
operational amplifiers. By using a bipolar front end, lower noise
and higher accuracy than those of CMOS designs have been
achieved. Both input and output ranges include the negative
supply, providing the user with zero-in/zero-out capability. For
users of 3.3 V systems such as lithium batteries, the OP295/OP495
are specified for 3 V operation.
OP495
+IN B
–IN B
OUT B
10 +IN C
9
8
–IN C
OUT C
Figure 3. 14-Lead PDIP
(P Suffix)
Maximum offset voltage is specified at 300 μV for 5 V operation,
and the open-loop gain is a minimum of 1000 V/mV. This yields
performance that can be used to implement high accuracy systems,
even in single-supply designs.
OUT A
–IN A
+IN A
V+
1
2
3
4
5
6
7
8
16 OUT D
15 –IN D
14 +IN D
13 V–
OP495
TOP VIEW
(Not to Scale)
+IN B
–IN B
OUT B
NC
12 +IN C
11 –IN C
10 OUT C
The ability to swing rail-to-rail and supply 15 mA to the load
makes the OP295/OP495 ideal drivers for power transistors and
H bridges. This allows designs to achieve higher efficiencies and
to transfer more power to the load than previously possible
without the use of discrete components.
9
NC
NC = NO CONNECT
Figure 4. 16-Lead SOIC_W
(S Suffix)
For applications such as transformers that require driving
inductive loads, increases in efficiency are also possible.
Stability while driving capacitive loads is another benefit of this
design over CMOS rail-to-rail amplifiers. This is useful for
driving coax cable or large FET transistors. The OP295/OP495
are stable with loads in excess of 300 pF.
The OP295 and OP495 are specified over the extended indus-
trial (−40°C to +125°C) temperature range. The OP295 is
available in 8-lead PDIP and 8-lead SOIC_N surface-mount
packages. The OP495 is available in 14-lead PDIP and 16-lead
SOIC_W surface-mount packages.
Rev. E
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registeredtrademarks arethe property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©2006 Analog Devices, Inc. All rights reserved.
OP295/OP495
TABLE OF CONTENTS
Features .............................................................................................. 1
Driving Heavy Loads ................................................................. 10
Direct Access Arrangement ...................................................... 10
Single-Supply Instrumentation Amplifier .............................. 10
Single-Supply RTD Thermometer Amplifier ......................... 11
Applications....................................................................................... 1
General Description......................................................................... 1
Pin Configurations ........................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Electrical Characteristics............................................................. 3
Absolute Maximum Ratings............................................................ 5
Thermal Resistance ...................................................................... 5
ESD Caution.................................................................................. 5
Typical Performance Characteristics ............................................. 6
Applications....................................................................................... 9
Rail-to-Rail Application Information........................................ 9
Low Drop-Out Reference............................................................ 9
Low Noise, Single-Supply Preamplifier..................................... 9
Cold Junction Compensated, Battery-Powered
Thermocouple Amplifier .......................................................... 11
5 V Only, 12-Bit DAC That Swings 0 V to 4.095 V.................... 11
4 to 20 mA Current-Loop Transmitter.................................... 12
3 V Low Dropout Linear Voltage Regulator............................. 12
Low Dropout, 500 mA Voltage Regulator with Foldback
Current Limiting ........................................................................ 12
Square Wave Oscillator.............................................................. 13
Single-Supply Differential Speaker Driver.............................. 13
High Accuracy, Single-Supply, Low Power Comparator ...... 13
Outline Dimensions....................................................................... 14
Ordering Guide .......................................................................... 16
REVISION HISTORY
5/06—Rev. D to Rev. E
3/02—Rev. B to Rev. C
Updated Format..................................................................Universal
Changes to Features.......................................................................... 1
Changes to Pin Connections........................................................... 1
Updated Outline Dimensions....................................................... 14
Changes to Ordering Guide .......................................................... 15
Figure changes to Pin Connections ................................................1
Deleted OP295GBC and OP495GBC from Ordering Guide ......3
Deleted Wafer Test Limits Table......................................................3
Changes to Absolute Maximum Ratings........................................4
Deleted Dice Characteristics............................................................4
2/04—Rev. C to Rev. D
Changes to General Description .................................................... 1
Changes to Specifications................................................................ 2
Changes to Absolute Maximum Ratings....................................... 4
Changes to Ordering Guide ............................................................ 4
Updated Outline Dimensions....................................................... 12
Rev. E | Page 2 of 16
OP295/OP495
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
VS = 5.0 V, VCM = 2.5 V, TA = 25°C, unless otherwise noted.
Table 1.
Parameter
Symbol
Conditions
Min
Typ
30
8
Max
Unit
INPUT CHARACTERISTICS
Offset Voltage
VOS
IB
300
800
20
30
3
μA
μA
nA
nA
nA
nA
−40°C ≤ TA ≤ +125°C
−40°C ≤ TA ≤ +125°C
−40°C ≤ TA ≤ +125°C
Input Bias Current
Input Offset Current
IOS
1
5
Input Voltage Range
VCM
0
4.0
V
Common-Mode Rejection Ratio
Large Signal Voltage Gain
CMRR
AVO
0 V ≤ VCM ≤ 4.0 V, −40°C ≤ TA ≤ +125°C
RL = 10 kΩ, 0.005 ≤ VOUT ≤ 4.0 V
RL = 10 kΩ, −40°C ≤ TA ≤ +125°C
90
1000
500
110
10,000
dB
V/mV
V/mV
μV/°C
Offset Voltage Drift
ΔVOS/ΔT
VOH
1
5
OUTPUT CHARACTERISTICS
Output Voltage Swing High
RL = 100 kΩ to GND
RL = 10 kΩ to GND
IOUT = 1 mA, −40°C ≤ TA ≤ +125°C
RL = 100 kΩ to GND
RL = 10 kΩ to GND
4.98
4.90
5.0
4.94
4.7
0.7
0.7
90
V
V
V
mV
mV
mV
mA
Output Voltage Swing Low
VOL
2
2
IOUT = 1 mA, −40°C ≤ TA ≤ +125°C
Output Current
IOUT
PSRR
ISY
11
18
POWER SUPPLY
Power Supply Rejection Ratio
1.5 V ≤ VS ≤ 15 V
1.5 V ≤ VS ≤ 15 V, –40°C ≤ TA ≤ +125°C
VOUT = 2.5 V, RL = ∞, −40°C ≤ TA ≤ +125°C
90
85
110
dB
dB
μA
Supply Current per Amplifier
DYNAMIC PERFORMANCE
Skew Rate
150
SR
GBP
θO
RL = 10 kΩ
0.03
75
86
V/μs
kHz
Degrees
Gain Bandwidth Product
Phase Margin
NOISE PERFORMANCE
Voltage Noise
en p-p
en
in
0.1 Hz to 10 Hz
f = 1 kHz
f = 1 kHz
1.5
51
<0.1
μV p-p
nV/√Hz
pA/√Hz
Voltage Noise Density
Current Noise Density
VS = 3.0 V, VCM = 1.5 V, TA = 25°C, unless otherwise noted.
Table 2.
Parameter
Symbol Conditions
Min
Typ
Max
Unit
INPUT CHARACTERISTICS
Offset Voltage
VOS
IB
IOS
VCM
100
8
1
500
20
3
μV
nA
nA
V
Input Bias Current
Input Offset Current
Input Voltage Range
0
2.0
Common-Mode Rejection Ration CMRR
0 V ≤ VCM ≤ 2.0 V, −40°C ≤ TA ≤ +125°C
RL = 10 kΩ
90
110
750
1
dB
V/mV
μV/°C
Large Signal Voltage Gain
Offset Voltage Drift
AVO
∆VOS/∆T
Rev. E | Page 3 of 16
OP295/OP495
Parameter
Symbol Conditions
Min
Typ
Max
Unit
OUTPUT CHARACTERISTICS
Output Voltage Swing High
Output Voltage Swing Low
POWER SUPPLY
VOH
VOL
RL = 10 kΩ to GND
RL = 10 kΩ to GND
2.9
V
mV
0.7
2
Power Supply Rejection Ratio
PSRR
ISY
1.5 V ≤ VS ≤ 15 V
1.5 V ≤ VS ≤ 15 V, −40°C ≤ TA ≤ +125°C
VOUT = 1.5 V, RL = ∞, −40°C ≤ TA ≤ +125°C
90
85
110
dB
dB
μA
Supply Current per Amplifier
DYNAMIC PERFORMANCE
Slew Rate
150
SR
GBP
θO
RL = 10 kΩ
0.03
75
85
V/μs
kHz
Degrees
Gain Bandwidth Product
Phase Margin
NOISE PERFORMANCE
Voltage Noise
en p-p
en
in
0.1 Hz to 10 Hz
f = 1 kHz
f = 1 kHz
1.6
53
<0.1
μV p-p
nV/√Hz
pA/√Hz
Voltage Noise Density
Current Noise Density
VS = 15.0 V, TA = 25°C, unless otherwise noted.
Table 3.
Parameter
Symbol Conditions
VOS
IB
Min
Typ
300
7
Max
Unit
INPUT CHARACTERISTICS
Offset Voltage
500
800
20
μV
μV
nA
−40°C ≤ TA ≤ +125°C
VCM = 0 V
Input Bias Current
VCM = 0 V, −40°C ≤ TA ≤ +125°C
VCM = 0 V
30
3
nA
nA
Input Offset Current
IOS
1
VCM = 0 V, −40°C ≤ TA ≤ +125°C
5
nA
Input Voltage Range
VCM
CMRR
AVO
−15
90
1000
+13.5
V
dB
V/mV
μV/°C
Common-Mode Rejection Ratio
Large Signal Voltage Gain
Offset Voltage Drift
−15.0 V ≤ VCM ≤ +13.5 V, −40°C ≤ TA ≤ +125°C
RL = 10 kΩ
110
4000
1
ΔVOS/ΔT
OUTPUT CHARACTERISTICS
Output Voltage Swing High
VOH
RL = 100 kΩ to GND
RL = 10 kΩ to GND
RL = 100 kΩ to GND
RL = 10 kΩ to GND
14.95
14.80
V
V
V
V
Output Voltage Swing Low
VOL
−14.95
−14.85
Output Current
IOUT
15
25
mA
POWER SUPPLY
Power Supply Rejection Ratio
PSRR
VS = 1.5 V to 15 V
VS = 1.5 V to 15 V, −40°C ≤ TA ≤ +125°C
VO = 0 V, RL = ∞, VS = 18 V, −40°C ≤ TA ≤ +125°C
90
85
110
dB
dB
μA
V
Supply Current per Amplifier
Supply Voltage Range
DYNAMIC PERFORMANCE
Slew Rate
ISY
VS
175
36 ( 18)
3 ( 1.5)
SR
GBP
θO
RL = 10 kΩ
0.03
85
83
V/μs
kHz
Degrees
Gain Bandwidth Product
Phase Margin
NOISE PERFORMANCE
Voltage Noise
en p-p
en
in
0.1 Hz to 10 Hz
f = 1 kHz
f = 1 kHz
1.25
45
<0.1
μV p-p
nV/√Hz
pA/√Hz
Voltage Noise Density
Current Noise Density
Rev. E | Page 4 of 16
OP295/OP495
ABSOLUTE MAXIMUM RATINGS
Table 4.
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Parameter1
Rating
18 V
Supply Voltage
Input Voltage
18 V
Differential Input Voltage2
Output Short-Circuit Duration
Storage Temperature Range
P, S Package
Operating Temperature Range
OP295G, OP495G
36 V
Indefinite
−65°C to +150°C
–40°C to +125°C
THERMAL RESISTANCE
θJA is specified for worst case mounting conditions; that is, θJA
is specified for device in socket for PDIP; θJA is specified for
device soldered to printed circuit board for SOIC package.
Junction Temperature Range
P, S Package
Lead Temperature (Soldering, 60 sec)
–65°C to +150°C
300°C
Table 5. Thermal Resistance
1 Absolute maximum ratings apply to packaged parts, unless otherwise noted.
2 For supply voltages less than 18 V, the absolute maximum input voltage is
equal to the supply voltage.
Package Type
θJA
103
158
83
θJC
43
43
39
30
Unit
°C/W
°C/W
°C/W
°C/W
8-Lead PDIP (P Suffix)
8-Lead SOIC_N (S Suffix)
14-Lead PDIP (P Suffix)
16-Lead SOIC_W (S Suffix)
98
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. E | Page 5 of 16
OP295/OP495
TYPICAL PERFORMANCE CHARACTERISTICS
140
200
175
150
125
100
75
BASED ON 600 OP AMPS
V
T
= 5V
= 25°C
S
A
120
100
80
60
40
20
V = 36V
S
V
= 5V
= 3V
S
S
V
50
25
0
–50
–25
0
25
50
75
100
–250 –200 –150 –100 –50
0
50
100 150 200 250
TEMPERATURE (°C)
INPUT OFFSET VOLTAGE (µV)
Figure 5. Supply Current Per Amplifier vs. Temperature
Figure 8. OP295 Input Offset (VOS) Distribution
15.2
15.0
14.8
14.6
14.4
14.2
250
225
200
175
150
125
100
75
BASED ON 600 OP AMPS
V
= 5V
V
= ±15V
R
= 100kΩ
S
S
L
–40°C ≤ T ≤ +85°C
A
R
R
= 10kΩ
= 2kΩ
L
L
–14.4
–14.6
–14.8
–15.0
–15.2
R
R
R
= 2kΩ
L
L
L
50
= 10kΩ
= 100kΩ
25
0
0
0.4
0.8
1.2
1.6
V (µV/°C)
OS
2.0
2.4
2.8
3.2
–50
–25
0
25
50
75
100
TEMPERATURE (°C)
T
C
Figure 9. OP295 TCVOS Distribution
Figure 6. Output Voltage Swing vs. Temperature
5.1
5.0
4.9
4.8
4.7
4.6
4.5
3.1
3.0
2.9
2.8
2.7
2.6
2.5
V
= 3V
S
V
= 5V
S
R
R
= 100kΩ
= 10kΩ
R
R
= 100kΩ
L
L
L
= 10kΩ
L
R
= 2kΩ
L
R
= 2kΩ
L
–50
–25
0
25
50
75
100
–50
–25
0
25
50
75
100
TEMPERATURE (°C)
TEMPERATURE (°C)
Figure 7. Output Voltage Swing vs. Temperature
Figure 10. Output Voltage Swing vs. Temperature
Rev. E | Page 6 of 16
OP295/OP495
500
450
400
350
300
250
200
150
100
50
40
35
30
25
20
15
10
5
BASED ON 1200 OP AMPS
V
T
= 5V
= 25°C
S
SOURCE
A
SINK
V
= ±15V
S
SOURCE
SINK
V
= +5V
S
0
–100
0
–50
–50
0
50
100
150
200
250
300
–25
0
25
50
75
100
INPUT OFFSET VOLTAGE (µV)
TEMPERATURE (°C)
Figure 11. OP495 Input Offset (VOS) Distribution
Figure 14. Output Current vs. Temperature
100
10
1
500
450
400
350
300
250
200
150
100
50
BASED ON 1200 OP AMPS
V
= 5V
V
V
= ±15V
= ±10V
S
S
–40°C ≤ T ≤ +85°C
A
O
R
= 100kΩ
= 10kΩ
L
R
R
L
= 2kΩ
L
0
0
0.4
0.8
1.2
1.6
V (µV/°C)
OS
2.0
2.4
2.8
3.2
–50
–25
0
25
50
75
100
TEMPERATURE (°C)
T
C
Figure 15. Open-Loop Gain vs. Temperature
Figure 12. OP495 TCVOS Distribution
20
16
12
8
12
10
8
V
V
= 5V
= 4V
V
= 5V
S
S
O
R
R
= 100kΩ
= 10kΩ
L
6
L
4
R
= 2kΩ
L
4
2
0
–50
0
–50
–25
0
25
50
75
100
–25
0
25
50
75
100
TEMPERATURE (°C)
TEMPERATURE (°C)
Figure 16. Open-Loop Gain vs. Temperature
Figure 13. Input Bias Current vs. Temperature
Rev. E | Page 7 of 16
OP295/OP495
V
T
= 5V
= 25°C
S
A
1V
100mV
10mV
1mV
SOURCE
SINK
100µV
1µA
10µA
100µA
1mA
10mA
LOAD CURRENT
Figure 17. Output Voltage to Supply Rail vs. Load Current
Rev. E | Page 8 of 16
OP295/OP495
APPLICATIONS
R5 and R6 set the gain of 1000, making this circuit ideal for
maximizing dynamic range when amplifying low level signals in
single-supply applications. The OP295/OP495 provide rail-to-
rail output swings, allowing this circuit to operate with 0 V to
5 V outputs. Only half of the OP295/OP495 is used, leaving the
other uncommitted op amp for use elsewhere.
RAIL-TO-RAIL APPLICATION INFORMATION
The OP295/OP495 have a wide common-mode input range
extending from ground to within about 800 mV of the positive
supply. There is a tendency to use the OP295/OP495 in buffer
applications where the input voltage could exceed the common-
mode input range. This can initially appear to work because of
the high input range and rail-to-rail output range. But above the
common-mode input range, the amplifier is, of course, highly
nonlinear. For this reason, there must be some minimal amount
of gain when rail-to-rail output swing is desired. Based on the
input common-mode range, this gain should be at least 1.2.
0.1µF
LED
R1
10µF
+
–
Q2
2N3906
3
1
5
7
R6
V
IN
10Ω
2
6
LOW DROP-OUT REFERENCE
Q1 MAT03 Q2
The OP295/OP495 can be used to gain up a 2.5 V or other low
voltage reference to 4.5 V for use with high resolution ADCs
that operate from 5 V only supplies. The circuit in Figure 18
supplies up to 10 mA. Its no-load drop-out voltage is only
20 mV. This circuit supplies over 3.5 mA with a 5 V supply.
C2
10µF
R5
10kΩ
2
3
–
+
8
4
V
OUT
R7
510Ω
1
OP295/OP495
C1
1500pF
R2
27kΩ
R3
R4
R8
100Ω
16kΩ
0.001µF
5V
5V
Figure 19. Low Noise Single-Supply Preamplifier
20kΩ
–
+
V
= 4.5V
The input noise is controlled by the MAT03 transistor pair and
the collector current level. Increasing the collector current
reduces the voltage noise. This particular circuit was tested with
1.85 mA and 0.5 mA of current. Under these two cases, the
input voltage noise was 3.1 nV/√Hz and 10 nV/√Hz, respectively.
The high collector currents do lead to a tradeoff in supply
current, bias current, and current noise. All of these parameters
increase with increasing collector current. For example,
typically the MAT03 has an hFE = 165. This leads to bias
currents of 11 μA and 3 μA, respectively. Based on the high bias
currents, this circuit is best suited for applications with low
source impedance such as magnetic pickups or low impedance
strain gauges. Furthermore, a high source impedance degrades
the noise performance. For example, a 1 kΩ resistor generates
4 nV/√Hz of broadband noise, which is already greater than the
noise of the preamp.
OUT
10Ω
2
REF43
4
+
6
1µF TO
10µF
1/2
OP295/OP495
Figure 18. 4.5 V, Low Drop-Out Reference
LOW NOISE, SINGLE-SUPPLY PREAMPLIFIER
Most single-supply op amps are designed to draw low supply
current at the expense of having higher voltage noise. This tradeoff
may be necessary because the system must be powered by a
battery. However, this condition is worsened because all circuit
resistances tend to be higher; as a result, in addition to the op
amp’s voltage noise, Johnson noise (resistor thermal noise) is
also a significant contributor to the total noise of the system.
The choice of monolithic op amps that combine the character-
istics of low noise and single-supply operation is rather limited.
Most single-supply op amps have noise on the order of 30 nV/√Hz
to 60 nV/√Hz, and single-supply amplifiers with noise below
5 nV/√Hz do not exist.
The collector current is set by R1 in combination with the LED
and Q2. The LED is a 1.6 V Zener diode that has a temperature
coefficient close to that of the Q2 base-emitter junction, which
provides a constant 1.0 V drop across R1. With R1 equal to
270 Ω, the tail current is 3.7 mA and the collector current is half
that, or 1.85 mA. The value of R1 can be altered to adjust the
collector current. When R1 is changed, R3 and R4 should also
be adjusted. To maintain a common-mode input range that
includes ground, the collectors of the Q1 and Q2 should not go
above 0.5 V; otherwise, they could saturate. Thus, R3 and R4
must be small enough to prevent this condition. Their values
and the overall performance for two different values of R1 are
summarized in Table 6.
To achieve both low noise and low supply voltage operation,
discrete designs may provide the best solution. The circuit in
Figure 19 uses the OP295/OP495 rail-to-rail amplifier and a
matched PNP transistor pair—the MAT03—to achieve zero-
in/zero-out single-supply operation with an input voltage noise
of 3.1 nV/√Hz at 100 Hz.
Rev. E | Page 9 of 16
OP295/OP495
Finally, the potentiometer, R8, is needed to adjust the offset
voltage to null it to zero. Similar performance can be obtained
using an OP90 as the output amplifier with a savings of about
185 ꢀA of supply current. However, the output swing does not
include the positive rail, and the bandwidth reduces to approxi-
mately 250 Hz.
100
90
Table 6. Single-Supply Low Noise Preamp Performance
IC = 1.85 mA
IC = 0.5 mA
10
R1
270 Ω
1.0 kΩ
0%
R3, R4
200 Ω
910 Ω
1ms
2V
2V
en @ 100 Hz
en @ 10 Hz
ISY
3.15 nV/√Hz
4.2 nV/√Hz
4.0 mA
11 ꢀA
1 kHz
1000
8.6 nV/√Hz
10.2 nV/√Hz
1.3 mA
3 μA
1 kHz
1000
Figure 21. H Bridge Outputs
IB
DIRECT ACCESS ARRANGEMENT
Bandwidth
Closed-Loop Gain
The OP295/OP495 can be used in a single-supply direct access
arrangement (DAA), as shown in Figure 22. This figure shows
a portion of a typical DM capable of operating from a single 5 V
supply, and it may also work on 3 V supplies with minor modi-
fications. Amplifier A2 and Amplifier A3 are configured so that
the transmit signal, TxA, is inverted by A2 and is not inverted
by A3. This arrangement drives the transformer differentially so
the drive to the transformer is effectively doubled over a single
amplifier arrangement. This application takes advantage of the
ability of the OP295/OP495 to drive capacitive loads and to save
power in single-supply applications.
DRIVING HEAVY LOADS
The OP295/OP495 are well suited to drive loads by using a
power transistor, Darlington, or FET to increase the current to
the load. The ability to swing to either rail can assure that the
device is turned on hard. This results in more power to the load
and an increase in efficiency over using standard op amps with
their limited output swing. Driving power FETs is also possible
with the OP295/OP495 because of their ability to drive capaci-
tive loads of several hundred picofarads without oscillating.
390pF
Without the addition of external transistors, the OP295/OP495
can drive loads in excess of 15 mA with 15 V or +30 V
supplies. This drive capability is somewhat decreased at lower
supply voltages. At 5 V supplies, the drive current is 11 mA.
37.4kΩ
OP295/
OP495 20kΩ
0.1µF
–
A1
+
RxA
0.0047µF
Driving motors or actuators in two directions in a single-supply
application is often accomplished using an H bridge. The
principle is demonstrated in Figure 20. From a single 5 V
supply, this driver is capable of driving loads from 0.8 V to
4.2 V in both directions. Figure 21 shows the voltages at the
inverting and noninverting outputs of the driver. There is a
small crossover glitch that is frequency-dependent; it does not
cause problems unless used in low distortion applications, such
as audio. If this is used to drive inductive loads, diode clamps
should be added to protect the bridge from inductive kickback.
3.3kΩ
20kΩ
+
475Ω
A2
–
OP295/
OP495
22.1kΩ
0.1µF
750pF
20kΩ
TxA
1:1
0.033µF
20kΩ
20kΩ
–
OP295/
OP495
5V
A3
+
2.5V REF
2N2222
2N2222
Figure 22. Direct Access Arrangement
10kΩ
OUTPUTS
2N2907
SINGLE-SUPPLY INSTRUMENTATION AMPLIFIER
0 ≤ V ≤ 2.5V
IN
5kΩ
–
The OP295/OP495 can be configured as a single-supply
instrumentation amplifier, as shown in Figure 23. For this
example, VREF is set equal to V+/2, and VO is measured with
respect to VREF. The input common-mode voltage range
includes ground, and the output swings to both rails.
+
1.67V
2N2907
10kΩ 10kΩ
–
+
Figure 20. H Bridge
Rev. E | Page 10 of 16
OP295/OP495
1/2
V+
8
COLD JUNCTION COMPENSATED, BATTERY-
POWERED THERMOCOUPLE AMPLIFIER
OP295/
OP495
5
6
+
–
+
–
V
7
O
1/2
V
The 150 μA quiescent current per amplifier consumption of the
OP295/OP495 makes them useful for battery-powered temperature
measuring instruments. The K-type thermocouple terminates
into an isothermal block where the terminated junctions’ ambient
temperatures can be continuously monitored and corrected by
summing an equal but opposite thermal EMF to the amplifier,
thereby canceling the error introduced by the cold junctions.
IN
4
OP295/
OP495
3
2
+
–
1
R1
100kΩ
R2
20kΩ
R3
R4
100kΩ
20kΩ
V
REF
R
G
24.9kΩ
1.235V
200kΩ
AD589
V
=
5 +
V
IN
)
+ V
REF
+
–
O
(
R
9V
G
SCALE
ADJUST
ISOTHERMAL
BLOCK
1N914
Figure 23. Single-Supply Instrumentation Amplifier
7.15kΩ
1%
24.3kΩ
1%
20kΩ
1.5MΩ
24.9kΩ
4.99kΩ
Resistor RG sets the gain of the instrumentation amplifier.
Minimum gain is 6 (with no RG). All resistors should be matched
in absolute value as well as temperature coefficient to maximize
common-mode rejection performance and minimize drift. This
instrumentation amplifier can operate from a supply voltage as
low as 3 V.
1.33MΩ
ALUMEL
–
1%
1%
1%
8
4
–
2
AL
COLD
JUNCTIONS
500Ω
10-TURN
1
V
O
3
+
OP295/
OP495
+
ZERO
ADJUST
CR
5V = 500°C
0V = 0°C
CHROMEL
475Ω
1%
2.1kΩ
1%
K-TYPE
THERMOCOUPLE
40.7µV/°C
Figure 25. Battery-Powered, Cold-Junction Compensated Thermocouple
Amplifier
SINGLE-SUPPLY RTD THERMOMETER AMPLIFIER
This RTD amplifier takes advantage of the rail-to-rail swing of
the OP295/OP495 to achieve a high bridge voltage in spite of a
low 5 V supply. The OP295/OP495 amplifier servos a constant
200 ꢀA current to the bridge. The return current drops across
the parallel resistors 6.19 kΩ and 2.55 Mꢁ, developing a voltage
that is servoed to 1.235 V, which is established by the AD589
band gap reference. The 3-wire RTD provides an equal line
resistance drop in both 100 ꢁ legs of the bridge, thus improving
the accuracy.
To calibrate, immerse the thermocouple measuring junction in
a 0°C ice bath and adjust the 500 Ω zero-adjust potentiometer
to 0 V out. Then immerse the thermocouple in a 250°C tem-
perature bath or oven and adjust the scale-adjust potentiometer
for an output voltage of 2.50 V, which is equivalent to 250°C.
Within this temperature range, the K-type thermocouple is
quite accurate and produces a fairly linear transfer characteristic.
Accuracy of 3°C is achievable without linearization.
Even if the battery voltage is allowed to decay to as low as 7 V,
the rail-to-rail swing allows temperature measurements to 700°C.
However, linearization may be necessary for temperatures above
250°C, where the thermocouple becomes rather nonlinear. The
circuit draws just under 500 ꢀA supply current from a 9 V
battery.
The AMP04 amplifies the differential bridge signal and converts
it to a single-ended output. The gain is set by the series resis-
tance of the 332 ꢁ resistor plus the 50 ꢁ potentiometer. The
gain scales the output to produce a 4.5 V full scale. The 0.22 ꢀF
capacitor to the output provides a 7 Hz low-pass filter to keep
noise at a minimum.
5 V ONLY, 12-BIT DAC THAT SWINGS 0 V TO 4.095 V
ZERO ADJ
50Ω
200Ω
Figure 26 shows a complete voltage output DAC with wide
output voltage swing operating off a single 5 V supply. The
serial input, 12-bit DAC is configured as a voltage output device
10-TURNS
5V
7
332Ω
26.7kΩ
0.5%
26.7kΩ
0.5%
1
3
2
0.22µF
6
+
8
with the 1.235 V reference feeding the current output pin (IOUT
)
V
AMP04
O
100Ω
RTD
5
–
of the DAC. The VREF, which is normally the input, now becomes
the output.
1/2
4
1
100Ω
0.5%
4.5V = 450°C
0V = 0°C
OP295/
OP495
–
2
+
3
The output voltage from the DAC is the binary weighted voltage
of the reference, which is gained up by the output amplifier such
that the DAC has a 1 mV per bit transfer function.
1.235
5V
37.4kΩ
2.55MΩ
6.19kΩ
1%
1%
AD589
Figure 24. Low Power RTD Amplifier
Rev. E | Page 11 of 16
OP295/OP495
5V
5V
I
< 50mA
+
L
8
MJE 350
5V
8
V
R1
O
2
1
V
DD
R
FB
17.8kΩ
+
44.2kΩ
D
V
100µF
IN
5V TO 3.2V
1%
V
=
(4.096V)
O
3
I
3
2
V
+
–
4096
REF
1.23V
8
4
DAC8043
OUT
3
2
+
–
1
30.9kΩ
1%
1
4
GND CLK SRI LD
OP295/
OP495
AD589
4
7
6
5
1/2
OP295/
OP495
1000pF
R4
100kΩ
R2
41.2kΩ
1.235V
DIGITAL
CONTROL
R3
5kΩ
43kΩ
AD589
TOTAL POWER DISSIPATION = 1.6mW
Figure 28. 3 V Low Dropout Voltage Regulator
Figure 26. A 5 V 12-Bit DAC with 0 V to 4.095 Output Swing
Figure 29 shows the regulator’s recovery characteristic when its
output underwent a 20 mA to 50 mA step current change.
4 TO 20 mA CURRENT-LOOP TRANSMITTER
Figure 27 shows a self-powered 4 to 20 mA current-loop
transmitter. The entire circuit floats up from the single-supply
(12 V to 36 V) return. The supply current carries the signal
within the 4 to 20 mA range. Thus, the 4 mA establishes the
baseline current budget within which the circuit must operate.
This circuit consumes only 1.4 mA maximum quiescent
current, making 2.6 mA of current available to power additional
signal conditioning circuitry or to power a bridge circuit.
2V
100
50mA
90
STEP
CURRENT
CONTROL
WAVEFORM
20mA
NULL ADJ
REF02
6
2
OUTPUT
10
+
GND
4
100kΩ
10-TURN
SPAN ADJ
0%
5V
20mV
1ms
1.21MΩ
10kΩ
10-TURN
100Ω
1%
–
V
8
4
IN
0V + 3V
3
2
+
–
12V
TO
36V
220Ω
182kΩ
1%
Figure 29. Output Step Load Current Recovery
1
2N1711
1/2
OP295/
OP495
LOW DROPOUT, 500 mA VOLTAGE REGULATOR
WITH FOLDBACK CURRENT LIMITING
4mA
TO
20mA
R
100Ω
L
220pF
Adding a second amplifier in the regulation loop, as shown in
Figure 30, provides an output current monitor as well as
foldback current limiting protection.
100Ω
1%
100kΩ
HP
5082-2800
1%
Figure 27. 4 to 20 mA Current Loop Transmitter
I
I
(NORM) = 0.5A
(MAX) = 1A
O
O
RSENSE
0.1Ω
1/4W
3 V LOW DROPOUT LINEAR VOLTAGE REGULATOR
IRF9531
S
D
5V V
O
Figure 28 shows a simple 3 V voltage regulator design. The
regulator can deliver 50 mA load current while allowing a
0.2 V dropout voltage. The OP295/OP495 rail-to-rail output
swing drives the MJE350 pass transistor without requiring
special drive circuitry. At no load, its output can swing less than
the pass transistor’s base-emitter voltage, turning the device
nearly off. At full load, and at low emitter-collector voltages, the
transistor beta tends to decrease. The additional base current is
easily handled by the OP295/OP495 output.
+
6V
–
210kΩ
205kΩ
G
1%
1%
8
5
6
+
1N4148
A2
7
–
1/2
45.3kΩ
1%
45.3kΩ
1%
OP295/
OP495
100kΩ
5%
0.01µF
3
2
+
–
124kΩ
1%
124kΩ
1%
A1
1
1/2
OP295/
OP495
4
The amplifier servos the output to a constant voltage, which
feeds a portion of the signal to the error amplifier.
2.5V
REF43
2
6
4
Higher output current, to 100 mA, is achievable at a higher
dropout voltage of 3.8 V.
Figure 30. Low Dropout, 500 mA Voltage Regulator
with Foldback Current Limiting
Rev. E | Page 12 of 16
OP295/OP495
V+
Amplifier A1 provides error amplification for the normal
voltage regulation loop. As long as the output current is less
than 1 A, the output of Amplifier A2 swings to ground, reverse-
biasing the diode and effectively taking itself out of the circuit.
However, as the output current exceeds 1 A, the voltage that
develops across the 0.1 ꢁ sense resistor forces the output of
Amplifier A2 to go high, forward-biasing the diode, which in
turn closes the current-limit loop. At this point, the A2’s lower
output resistance dominates the drive to the power MOSFET
transistor, thereby effectively removing the A1 voltage regula-
tion loop from the circuit.
100kΩ
58.7kΩ
8
4
3
2
+
–
1
FREQ OUT
1/2
OP295/
OP495
1
F
=
< 350Hz @ V+ = 5V
OSC
100kΩ
RC
+
R
C
Figure 31. Square Wave Oscillator Has Stable Frequency Regardless of
Supply Changes
If the output current greater than 1 A persists, the current limit
loop forces a reduction of current to the load, which causes a
corresponding drop in output voltage. As the output voltage
drops, the current-limit threshold also drops fractionally,
resulting in a decreasing output current as the output voltage
decreases, to the limit of less than 0.2 A at 1 V output. This fold-
back effect reduces the power dissipation considerably during a
short circuit condition, thus making the power supply far more
forgiving in terms of the thermal design requirements. Small
heat sinking on the power MOSFET can be tolerated.
90.9kΩ
10kΩ
10kΩ
V+
–
2.2µF
+
+
1/4
OP295/
OP495
V
+
IN
100kΩ
SPEAKER
–
+
–
+
1/4
1/4
OP295/
OP495
OP295/
OP495
20kΩ
20kΩ
V+
The rail-to-rail swing of the OP295 exacts higher gate drive to
the power MOSFET, providing a fuller enhancement to the tran-
sistor. The regulator exhibits 0.2 V dropout at 500 mA of load
current. At 1 A output, the dropout voltage is typically 5.6 V.
Figure 32. Single-Supply Differential Speaker Driver
HIGH ACCURACY, SINGLE-SUPPLY, LOW POWER
COMPARATOR
SQUARE WAVE OSCILLATOR
The OP295/OP495 make accurate open-loop comparators.
With a single 5 V supply, the offset error is less than 300 ꢀV.
Figure 33 shows the response time of the OP295/OP495 when
operating open-loop with 4 mV overdrive. They exhibit a 4 ms
response time at the rising edge and a 1.5 ms response time at
the falling edge.
The circuit in Figure 31 is a square wave oscillator (note the
positive feedback). The rail-to-rail swing of the OP295/OP495
helps maintain a constant oscillation frequency even if the supply
voltage varies considerably. Consider a battery-powered system
where the voltages are not regulated and drop over time. The
rail-to-rail swing ensures that the noninverting input sees the
full V+/2, rather than only a fraction of it.
1V
100
The constant frequency comes from the fact that the 58.7 kꢁ
feedback sets up Schmitt trigger threshold levels that are directly
proportional to the supply voltage, as are the RC charge voltage
levels. As a result, the RC charge time, and therefore, the frequency,
remain constant independent of supply voltage. The slew rate of
the amplifier limits oscillation frequency to a maximum of about
800 Hz at a 5 V supply.
90
INPUT
(5mV OVERDRIVE
@ OP295 INPUT)
OUTPUT
10
SINGLE-SUPPLY DIFFERENTIAL SPEAKER DRIVER
0%
2V
5ms
Connected as a differential speaker driver, the OP295/OP495
can deliver a minimum of 10 mA to the load. With a 600 ꢁ load,
the OP295/OP495 can swing close to 5 V p-p across the load.
Figure 33. Open-Loop Comparator Response Time with 5 mV Overdrive
Rev. E | Page 13 of 16
OP295/OP495
OUTLINE DIMENSIONS
0.400 (10.16)
0.365 (9.27)
0.355 (9.02)
8
5
4
0.280 (7.11)
0.250 (6.35)
0.240 (6.10)
1
0.325 (8.26)
0.310 (7.87)
0.300 (7.62)
PIN 1
0.100 (2.54)
BSC
0.060 (1.52)
MAX
0.195 (4.95)
0.130 (3.30)
0.115 (2.92)
0.210
(5.33)
MAX
0.015
(0.38)
MIN
0.150 (3.81)
0.130 (3.30)
0.115 (2.92)
0.015 (0.38)
GAUGE
0.014 (0.36)
0.010 (0.25)
0.008 (0.20)
PLANE
SEATING
PLANE
0.022 (0.56)
0.018 (0.46)
0.014 (0.36)
0.430 (10.92)
MAX
0.005 (0.13)
MIN
0.070 (1.78)
0.060 (1.52)
0.045 (1.14)
COMPLIANT TO JEDEC STANDARDS MS-001-BA
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
CORNER LEADS MAY BE CONFIGURED AS WHOLE OR HALF LEADS.
Figure 34. 8-Lead Plastic Dual In-Line Package [PDIP]
(N-8) P Suffix
Dimensions shown in inches and (millimeters)
5.00 (0.1968)
4.80 (0.1890)
8
1
5
4
6.20 (0.2440)
5.80 (0.2284)
4.00 (0.1574)
3.80 (0.1497)
1.27 (0.0500)
BSC
0.50 (0.0196)
0.25 (0.0099)
× 45°
1.75 (0.0688)
1.35 (0.0532)
0.25 (0.0098)
0.10 (0.0040)
8°
0.51 (0.0201)
0.31 (0.0122)
0° 1.27 (0.0500)
COPLANARITY
0.10
0.25 (0.0098)
0.17 (0.0067)
SEATING
PLANE
0.40 (0.0157)
COMPLIANT TO JEDEC STANDARDS MS-012-AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 35. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body (R-8) S Suffix
Dimensions shown in millimeters and (inches)
Rev. E | Page 14 of 16
OP295/OP495
0.775 (19.69)
0.750 (19.05)
0.735 (18.67)
14
1
8
7
0.280 (7.11)
0.250 (6.35)
0.240 (6.10)
0.325 (8.26)
0.310 (7.87)
0.300 (7.62)
PIN 1
0.100 (2.54)
BSC
0.060 (1.52)
MAX
0.195 (4.95)
0.130 (3.30)
0.115 (2.92)
0.210
(5.33)
MAX
0.015
(0.38)
MIN
0.150 (3.81)
0.130 (3.30)
0.110 (2.79)
0.015 (0.38)
GAUGE
0.014 (0.36)
0.010 (0.25)
0.008 (0.20)
PLANE
SEATING
PLANE
0.022 (0.56)
0.018 (0.46)
0.014 (0.36)
0.430 (10.92)
MAX
0.005 (0.13)
MIN
0.070 (1.78)
0.050 (1.27)
0.045 (1.14)
COMPLIANT TO JEDEC STANDARDS MS-001-AA
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
CORNER LEADS MAY BE CONFIGURED AS WHOLE OR HALF LEADS.
Figure 36. 14-Lead Plastic Dual In-Line Package [PDIP]
(N-14) P Suffix
Dimensions shown in inches and (millimeters)
10.50 (0.4134)
10.10 (0.3976)
16
1
9
8
7.60 (0.2992)
7.40 (0.2913)
10.65 (0.4193)
10.00 (0.3937)
1.27 (0.0500)
0.75 (0.0295)
0.25 (0.0098)
2.65 (0.1043)
2.35 (0.0925)
BSC
×
45°
0.30 (0.0118)
0.10 (0.0039)
8°
0°
0.51 (0.0201)
0.31 (0.0122)
SEATING
PLANE
COPLANARITY
0.10
1.27 (0.0500)
0.40 (0.0157)
0.33 (0.0130)
0.20 (0.0079)
COMPLIANT TO JEDEC STANDARDS MS-013-AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 37. 16-Lead Standard Small Outline Package [SOIC_W]
Wide Body (RW-16) S Suffix
Dimensions shown in millimeters and (inches)
Rev. E | Page 15 of 16
OP295/OP495
ORDERING GUIDE
Model
OP295GP
OP295GPZ1
Temperature Range
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
Package Description
8-Lead Plastic DIP
8-Lead Plastic DIP
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
Package Option
P-Suffix (N-8)
P-Suffix (N-8)
S-Suffix (R-8)
S-Suffix (R-8)
S-Suffix (R-8)
S-Suffix (R-8)
S-Suffix (R-8)
S-Suffix (R-8)
OP295GS
OP295GS-REEL
OP295GS-REEL7
OP295GSZ1
OP295GSZ-REEL1
OP295GSZ-REEL71
OP495GP
OP495GPZ1
OP495GS
OP495GS-REEL
OP495GSZ1
OP495GSZ-REEL1
14-Lead Plastic DIP
14-Lead Plastic DIP
16-Lead SOIC_W
16-Lead SOIC_W
16-Lead SOIC_W
16-Lead SOIC_W
P-Suffix (N-14)
P-Suffix (N-14)
S-Suffix (RW-16)
S-Suffix (RW-16)
S-Suffix (RW-16)
S-Suffix (RW-16)
1 Z = Pb-free part.
©2006 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
C00331-0-5/06(E)
Rev. E | Page 16 of 16
相关型号：
OP496GBC
IC QUAD OP-AMP, 300 uV OFFSET-MAX, 0.35 MHz BAND WIDTH, UUC14, 0.062 X 0.092 INCH, DIE-14, Operational Amplifier
ADI
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