LT1491IS [ETC]
Voltage-Feedback Operational Amplifier ; 电压反馈运算放大器\n
| 型号： | LT1491IS |
| 厂家： | 
ETC |
| 描述： | Voltage-Feedback Operational Amplifier
|
| 文件： | 总12页 (文件大小：250K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT1490/LT1491
Dual and Quad
Micropower Rail-to-Rail
Input and Output Op Amps
U
FEATURES
DESCRIPTIO
The dual LT®1490 and quad LT1491 op amps operate on all
single and split supplies with a total voltage of 2V to 44V
drawing only 40µA of quiescent current per amplifier. These
amplifiersarereversesupplyprotected;theydrawnocurrent
for reverse supply up to 18V. The input range of the LT1490/
LT1491includesbothsuppliesandtheoutputswingstoboth
supplies. Unlike most micropower op amps, the LT1490/
LT1491 can drive heavy loads; their rail-to-rail outputs drive
20mA.TheLT1490/LT1491areunity-gainstableanddriveall
capacitive loads up to 10,000pF when optional 0.22µF and
150Ω compensation is used.
■
Rail-to-Rail Input and Output
■
Single Supply Input Range: –0.4V to 44V
■
Micropower: 50µA/Amplifier Max
■
MSOP Package
■
Specified on 3V, 5V and ±15V Supplies
■
High Output Current: 20mA
■
Output Drives 10,000pF with Output Compensation
■
Reverse Battery Protection to 18V
■
No Supply Sequencing Problems
■
High Voltage Gain: 1500V/mV
■
High CMRR: 98dB
No Phase Reversal
■
The LT1490/LT1491 have a unique input stage that oper-
ates and remains high impedance when above the positive
supply. The inputs take 44V both differential and common
mode even when operating on a 3V supply. Built-in resis-
tors protect the inputs for faults below the negative supply
upto22V.Thereisnophasereversaloftheoutputforinputs
22V below V– or 44V above V–, independent of V+.
■
Gain Bandwidth Product: 200kHz
U
APPLICATIO S
■
Battery- or Solar-Powered Systems
Portable Instrumentation
Sensor Conditioning
The LT1490 dual op amp is available in the 8-pin MSOP,
SO and PDIP packages. The quad LT1491 is available in
the 14-pin SO and PDIP packages.
■
Supply Current Sensing
■
Battery Monitoring
■
Micropower Active Filters
For new designs it is recommended that the LT1490A/
LT1491A be used instead of the LT1490/LT1491. See the
LT1490A/LT1491A data sheet for details.
■
4mA to 20mA Transmitters
, LTC and LT are registered trademarks of Linear Technology Corporation.
U
TYPICAL APPLICATIO
Battery Monitor
R
R
S
A
0.2Ω
2k
Q1
2N3904
CHARGER
VOLTAGE
+
A
R
I
A
'
BATT
–
1/4 LT1491
2k
C
LOGIC
–
1/4 LT1491
+
R
B
Q2
2k
LOGIC HIGH (5V) = CHARGING
2N3904
+
LOGIC LOW (0V) = DISCHARGING
B
R
B
'
1/4 LT1491
2k
–
LOAD
+
D
+
R
G
V
1/4 LT1491
OUT
10k
V
BATT
= 12V
–
S1
10k
90.9k
V
V
=
OUT
OUT
S1 = OPEN, GAIN = 1
S1 = CLOSED, GAIN = 10
R
= R
A
S
B
I
=
AMPS
BATT
1490/91 TA01
(R )(R /R )(GAIN) GAIN
V
= 5V, 0V
S
G
A
1
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LT1490/LT1491
W W
U W
ABSOLUTE AXI U RATI GS (Note 1)
Total Supply Voltage (V+ to V–) .............................. 44V
Input Differential Voltage ......................................... 44V
Input Current ...................................................... ±25mA
Output Short-Circuit Duration (Note 2).........Continuous
Operating Temperature Range ................ –40°C to 85°C
Junction Temperature........................................... 150°C
Specified Temperature Range (Note 3) .. –40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
U
W U
PACKAGE/ORDER INFORMATION(For new designs, use the LT1490A or LT1491A)
ORDER PART
ORDER PART
NUMBER
TOP VIEW
NUMBER
TOP VIEW
OUT A
–IN A
+IN A
1
2
3
4
5
6
7
14 OUT D
13 –IN D
+
LT1490CMS8
LT1490CN8
LT1490CS8
LT1490IN8
LT1490IS8
1
2
3
4
8
7
6
5
OUT A
–IN A
+IN A
V
LT1491CN
LT1491CS
LT1491IN
LT1491IS
A
B
OUT B
–IN B
+IN B
D
C
12 +IN D
–
A
+
V
11
V
B
–
V
+IN B
–IN B
OUT B
10 +IN C
9
8
– IN C
OUT C
MS8 PACKAGE
8-LEAD MSOP
N8 PACKAGE
8-LEAD PDIP
MS8 PART MARKING
LTBB
S8 PACKAGE
8-LEAD PLASTIC SO
N PACKAGE
S PACKAGE
14-LEAD PDIP 14-LEAD PLASTIC SO
T
JMAX = 150°C, θJA = 250°C/ W (MS8)
TJMAX = 150°C, θJA = 130°C/ W (N8)
TJMAX = 150°C, θJA = 110°C/ W (N)
S8 PART MARKING
1490 1490I
T
JMAX = 150°C, θJA = 190°C/ W (S8)
T
JMAX = 150°C, θJA = 150°C/ W (S)
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. VS = 3V, 0V; VS = 5V, 0V; VCM = VOUT = half supply, unless otherwise noted. (Note 3)
SYMBOL
V
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Offset Voltage
LT1490 N Package
220
800
1000
1100
µV
µV
µV
OS
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
LT1490 S Package
220
300
350
950
1200
1300
µV
µV
µV
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
LT1491 N Package
1100
1350
1450
µV
µV
µV
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
LT1490CMS8 Package, LT1491 S Package
1450
1650
1750
µV
µV
µV
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V
TC
Input Offset Voltage Drift
Input Offset Current
Input Bias Current
0°C ≤ T ≤ 70°C (Note 7)
●
●
2
2
4
4
µV/°C
µV/°C
OS
A
–40°C ≤ T ≤ 85°C (Note 7)
A
I
I
●
●
0.2
0.8
0.8
nA
µA
OS
V
= 44V (Note 4)
= 44V (Note 4)
CM
●
●
4
4
0.1
8
10
nA
µA
nA
B
V
CM
S
V = 0V
Input Noise Voltage
0.1Hz to 10Hz
1
µV
P-P
2
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LT1490/LT1491
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. VS = 3V, 0V; VS = 5V, 0V; VCM = VOUT = half supply, unless otherwise noted. (Note 3)
SYMBOL
PARAMETER
CONDITIONS
f = 1kHz
MIN
TYP
50
MAX
UNITS
nV/√Hz
pA/√Hz
e
Input Noise Voltage Density
Input Noise Current Density
Input Resistance
n
i
f = 1kHz
0.03
n
R
IN
Differential
Common Mode, V = 0V to 44V
6
4
17
11
MΩ
MΩ
CM
C
Input Capacitance
4.6
pF
V
IN
Input Voltage Range
●
0
44
CMRR
Common Mode Rejection Ratio
(Note 4)
V
V
= 0V to V – 1V
●
●
84
80
98
98
dB
dB
CM
CM
CC
= 0V to 44V
A
Large-Signal Voltage Gain
V = 3V, V = 500mV to 2.5V, R = 10k
200
133
100
1500
V/mV
V/mV
V/mV
VOL
S
O
L
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V = 5V, V = 500mV to 4.5V, R = 10k
400
250
200
1500
V/mV
V/mV
V/mV
S
O
L
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V
V
Output Voltage Swing Low
V = 3V, No Load
●
●
22
50
mV
mV
OL
OH
S
V = 3V, I
= 5mA
250
450
S
SINK
V = 5V, No Load
●
●
22
250
330
50
500
500
mV
mV
mV
S
V = 5V, I
= 5mA
= 10mA
S
SINK
SINK
V = 5V, I
S
Output Voltage Swing High
V = 3V, No Load
●
●
2.95
2.55
2.978
2.6
V
V
S
V = 3V, I
= 5mA
S
SOURCE
V = 5V, No Load
●
●
4.95
4.30
4.978
4.6
V
V
S
V = 5V, I
= 10mA
S
SOURCE
I
Short-Circuit Current (Note 2)
V = 3V, Short to GND
10
10
15
30
mA
mA
SC
S
V = 3V, Short to V
S
CC
V = 5V, Short to GND
15
15
25
30
mA
mA
S
V = 5V, Short to V
S
CC
PSRR
Power Supply Rejection Ratio
Minimum Operating Supply Voltage
Reverse Supply Voltage
V = 2.5V to 12.5V, V = V = 1V
●
●
●
84
98
2
dB
V
S
CM
O
2.5
I = –100µA per Amplifier
S
18
27
40
V
I
Supply Current per Amplifier
(Note 5)
50
55
µA
µA
S
●
GBW
SR
Gain Bandwidth Product
(Note 4)
f = 1kHz
110
100
90
180
kHz
kHz
kHz
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
Slew Rate
(Note 6)
A = –1, R = ∞
0.035
0.031
0.030
0.06
V/µs
V/µs
V/µs
V
L
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
3
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LT1490/LT1491
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. VS = ±15V, VCM = 0V, VOUT = 0V, unless otherwise noted. (Note 3)
SYMBOL
V
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Offset Voltage
LT1490 N, S Package
250
1200
1400
1500
µV
µV
µV
OS
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
LT1491 N Package
350
400
1250
1500
1600
µV
µV
µV
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
LT1490CMS8 Package, LT1491 S Package
1600
1850
1950
µV
µV
µV
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V
TC
Input Offset Voltage Drift
0°C ≤ T ≤ 70°C (Note 7)
●
●
3
3
6
6
µV/°C
µV/°C
OS
A
–40°C ≤ T ≤ 85°C (Note 7)
A
I
I
Input Offset Current
Input Bias Current
●
●
0.2
4
0.8
8
nA
nA
OS
B
Input Noise Voltage
Input Noise Voltage Density
Input Noise Current Density
Input Resistance
0.1Hz to 10Hz
f = 1kHz
1
µV
P-P
e
50
0.03
nV/√Hz
pA/√Hz
n
i
f = 1kHz
n
R
Differential
Common Mode, V = –15V to 14V
6
17
15000
MΩ
MΩ
IN
CM
C
Input Capacitance
4.6
pF
V
IN
Input Voltage Range
●
●
–15
80
29
CMRR
Common Mode Rejection Ratio
Large-Signal Voltage Gain
V
= –15V to 29V
98
dB
CM
A
V = ±14V, R = 10k
0°C ≤ T ≤ 70°C
–40°C ≤ T ≤ 85°C
100
75
50
250
V/mV
V/mV
V/mV
VOL
O
L
●
●
A
A
V
Output Voltage Swing
No Load
●
●
±14.9
±14.5
±14.5
±14.978
±14.750
±14.670
V
V
V
O
I
I
= ±5mA
= ±10mA
OUT
OUT
I
Short-Circuit Current (Note 2)
Short to GND
0°C ≤ T ≤ 70°C
±20
±15
±10
±25
mA
mA
mA
SC
●
●
A
–40°C ≤ T ≤ 85°C
A
PSRR
Power Supply Rejection Ratio
Supply Current per Amplifier
V = ±1.25V to ±22V
S
●
88
98
50
dB
I
70
85
µA
µA
S
●
GBW
SR
Gain Bandwidth Product
Slew Rate
f = 1kHz
125
110
100
200
kHz
kHz
kHz
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
A = –1, R = ∞, V = ±10V,
0.0375
0.07
V/µs
V
L
O
Measure at V = ±5V
O
0°C ≤ T ≤ 70°C
●
●
0.0330
0.0300
V/µs
V/µs
A
–40°C ≤ T ≤ 85°C
A
Note 1: Absolute Maximum Ratings are those values beyond which the
life of the device may be impaired.
The LT1490I/LT1491I are guaranteed to meet specified performance from
–40°C to 85°C.
Note 2: A heat sink may be required to keep the junction temperature
below absolute maximum. This depends on the power supply voltage
and how many amplifiers are shorted.
Note 4: V = 5V limits are guaranteed by correlation to V = 3V and
S S
V = ±15V tests.
S
Note 5: V = 3V limits are guaranteed by correlation to V = 5V and
S
S
Note 3: The LT1490C/LT1491C are guaranteed to meet specified
performance from 0°C to 70°C. The LT1490C/LT1491C are designed,
characterized and expected to meet specified performance from –40°C
to 85°C but are not tested or QA sampled at these temperatures.
V = ±15V tests.
S
Note 6: Guaranteed by correlation to slew rate at V = ±15V and GBW
S
at V = 3V and V = ±15V tests.
S
S
Note 7: This parameter is not 100% tested.
4
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LT1490/LT1491
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Input Bias Current
vs Common Mode Voltage
Supply Current vs Supply Voltage
Minimum Supply Voltage
80
70
60
50
40
30
20
10
0
400
300
6000
4000
V
S
= 5V, 0V
T
= 125°C
A
T
200
100
2000
= 25°C
A
T
A
= –55°C
T
= 25°C
A
0
30
20
T
A
= –55°C
T
A
= –55°C
–100
–200
–300
10
0
T
= 25°C
A
T
= 125°C
T
A
= 125°C
A
–400
–10
0
5
10 15 20 25 30 35 40 45
TOTAL SUPPLY VOLTAGE (V)
0
1
2
3
4
5
4.0
4.4
4.8
5.2
5.6
44
TOTAL SUPPLY VOLTAGE (V)
COMMON MODE VOLTAGE (V)
1490/91 G01
1490/91 G02
1490/91 G03
Output Saturation Voltage
Output Saturation Voltage
Output Saturation Voltage
vs Input Overdrive
vs Load Current (Output High)
vs Load Current (Output Low)
1
1
100
90
80
70
60
50
40
30
20
10
0
V
V
= ±2.5V
OD
V
V
= ±2.5V
S
= 30mV
OD
V
= ±2.5V
S
S
= 30mV
NO LOAD
T
= 125°C
T
= 125°C
A
A
0.1
0.1
T
= 25°C
A
T
= 25°C
A
T
= –55°C
T
= –55°C
A
A
OUTPUT HIGH
OUTPUT LOW
0.01
0.01
0.001
0.01
0.1
1
10
0.001
0.01
0.1
1
10
0
10 20 30 40 50 60 70 80 90 100
INPUT OVERDRIVE (mV)
1490/91 G06
SOURCING LOAD CURRENT (mA)
SINKING LOAD CURRENT (mA)
1490/90 G04
1490/90 G05
Noise Voltage Density
vs Frequency
0.1Hz to 10Hz Noise Voltage
Input Noise Current vs Frequency
80
70
60
50
40
30
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
V
= ±2.5V
S
1
10
100
1k
0
1
2
3
4
5
6
7
8
9
10
1
10
100
1k
TIME (SEC)
FREQUENCY (Hz)
FREQUENCY (Hz)
1490/91 G08
1490/91 G09
1490 G07
5
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LT1490/LT1491
TYPICAL PERFOR A CE CHARACTERISTICS
U W
Gain and Phase Shift
vs Frequency
Gain Bandwidth Product
vs Temperature
Slew Rate vs Temperature
0.12
0.10
0.08
0.06
0.04
260
240
220
200
180
160
140
120
100
70
60
50
40
100
80
V
= ±2.5V
f = 1kHz
S
RISING, V = ±15V
S
60
PHASE
40
30
20
20
0
V
S
= ±15V
RISING, V = ±1.5V
S
FALLING, V = ±15V
GAIN
V
= ±3V
S
S
10
0
–20
–40
–60
–80
–100
FALLING, V = ±1.5V
S
–10
–20
–30
50
75 100 125
–50
0
25
50
75 100 125
–50
0
25
–25
–25
1
10
100
1000
TEMPERATURE (°C)
TEMPERATURE (°C)
FREQUENCY (kHz)
1490/91 G10
1490/91 G11
1490/91 G12
Gain Bandwidth Product and
Phase Margin vs Supply Voltage
CMRR vs Frequency
PSRR vs Frequency
250
240
230
220
210
200
190
180
170
160
150
60
50
40
30
20
10
120
100
80
80
70
V
S
= ±2.5V
PHASE MARGIN
60
50
V
= ±15V
POSITIVE SUPPLY
S
40
V
S
= ±1.5V
30
GAIN BANDWIDTH
60
20
NEGATIVE SUPPLY
10
0
40
R
= 10k
L
–10
–20
f = 1kHz
20
0
5
10 15 20 25 30 35 40 45
TOTAL SUPPLY VOLTAGE (V)
1
10
100
1
10
FREQUENCY (kHz)
100
FREQUENCY (kHz)
1490 G14
1490/91 G15
1490/91 G13
Gain Bandwidth Product and
Phase Margin vs Load Resistance
Channel Separation vs Frequency
Output Impedance vs Frequency
350
300
250
200
150
100
50
80
10k
1k
130
120
110
100
90
V
S
= ±2.5V
V
A
= ±2.5V
V
S
= ±15V
S
V
F
= –1
R = R = 100k 70
G
f = 1kHz
A
A
= 100
= 10
V
V
PHASE MARGIN
60
50
40
30
20
100
10
80
GAIN BANDWIDTH
70
A
V
= 1
60
1
50
0.1
40
1
10
LOAD RESISTANCE (kΩ)
100
0.1
1
10
100
0.1
1
10
100
FREQUENCY (kHz)
FREQUENCY (kHz)
1490/91 G16
1490/91 G17
1490/91 G18
6
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LT1490/LT1491
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Undistorted Output Swing
vs Frequency
Settling Time to 0.1%
vs Output Step
Capacitive Load Handling,
Overshoot vs Capacitive Load
10
8
100
90
80
70
60
50
40
30
20
10
0
35
30
25
20
15
10
5
V
S
= ±15V
V = 5V, 0V
S
DISTORTION ≤1%
V
= ±15V
S
I
= 170µA
SOURCE
A
= –1
V
6
A
V
= 1
4
2
0
A
V
= 10
–2
–4
–6
–8
–10
A
V
= 1
A
V
= 2
A
V
= 5
V
= ±2.5V
A = –1
V
S
A
V
= 1
0
0
80
120 140
160
10
100
1000
10000
20 40 60
100
0.1
1
10
100
SETTLING TIME (µs)
CAPACITIVE LOAD (pF)
FREQUENCY (kHz)
1490/91 G21
1490/91 G19
1490/91 F20
Total Harmonic Distortion + Noise
vs Frequency
Total Harmonic Distortion + Noise
vs Load Resistance
Total Harmonic Distortion + Noise
vs Output Voltage
10
1
10
1
10
1
V
V
V
= 3V, 0V
= 2V
CM
= 50k
V
A
V
= 3V TOTAL
= 1
R
V
= 10k
CM
f = 1kHz
S
OUT
S
V
L
= HALF SUPPLY
P-P
= 1.2V
= 2V AT 1kHz
IN
P-P
R
L
V
V
= ±1.5V
= ±1V
S
IN
A
V
= 1
= ±1.5V
V
S
A
S
= –1
V
V
= ±1.5V
0.1
0.1
0.1
V
V
= 3V, 0V
IN
S
= 0.5V TO 2.5V
A
S
= –1
0.01
0.01
0.01
0.001
V
A
= –1
V
V
= 3V, 0V
A
= 1
V
V
V
= 3V, 0V
IN
S
A
= 1
V
V
= 3V, 0V
S
= 0.2V TO 2.2V
0.001
0.001
0
1
2
3
0.01
0.1
1
10
0.1
1
10
100
OUTPUT VOLTAGE (V
)
P-P
FREQUENCY (kHz)
LOAD RESISTANCE TO GROUND (kΩ)
1490/91 G24
1490/91 G22
1490/91 G23
Open-Loop Gain
Large-Signal Response
Small-Signal Response
VS = ±15V
RL = 2k
R
= 10k
L
RL = 50k
VS = ±15V
AV = –1
V
S = ±15V
1490/91 G27
–10V
0V
10V
1490/91 G25
1490/91 G26
AV = 1
OUTPUT VOLTAGE (5V/DIV)
7
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LT1490/LT1491
W U U
U
APPLICATIO S I FOR ATIO
Supply Voltage
The inputs are protected against excursions as much as
22V below V– by an internal 1k resistor in series with each
input and a diode from the input to the negative supply.
There is no output phase reversal for inputs up to 22V
below V–. There are no clamping diodes between the
inputs and the maximum differential input voltage is 44V.
The positive supply pin of the LT1490/LT1491 should be
bypassed with a small capacitor (about 0.01µF) within an
inch of the pin. When driving heavy loads an additional
4.7µF electrolytic capacitor should be used. When using
split supplies, the same is true for the negative supply pin.
The LT1490/LT1491 are protected against reverse battery
voltagesupto18V. Intheeventareversebatterycondition
occurs, the supply current is less than 1nA.
The LT1490/LT1491 can be shut down by removing V+. In
this condition the input bias current is less than 0.1nA,
even if the inputs are 44V above the negative supply.
Output
The output voltage swing of the LT1490/LT1491 is af-
fected by input overdrive as shown in the typical perfor-
mance curves. When monitoring voltages within 100mV
of either rail, gain should be taken to keep the output from
clipping.
When operating the LT1490/LT1491 on total supplies of
30V or more, the supply must not be brought up faster
than 1µs. This is especially true if low ESR bypass capaci-
tors are used. A series RLC circuit is formed from the
supply lead inductance and the bypass capacitor. 5Ω of
resistance in the supply or the bypass capacitor will
dampen the tuned circuit enough to limit the rise time.
The output of the LT1490/LT1491 can be pulled up to 18V
beyondV+ withlessthan1nAofleakagecurrent, provided
that V+ is less than 0.5V.
The normally reverse-biased substrate diode from the
outputtoV– willcauseunlimitedcurrentstoflowwhenthe
output is forced below V–. If the current is transient and
limited to 100mA, no damage will occur.
Inputs
The LT1490/LT1491 is internally compensated to drive at
least 200pF of capacitance under any output loading
conditions. A 0.22µF capacitor in series with a 150Ω
resistor between the output and ground will compensate
theseamplifiersforlargercapacitiveloads,upto10,000pF,
at all output currents.
The LT1490/LT1491 have two input stages, NPN and PNP
(see the Simplified Schematic), resulting in three distinct
operating regions as shown in the Input Bias Current vs
Common Mode typical performance curve.
For input voltages about 0.8V or more below V+, the PNP
input stage is active and the input bias current is typically
–4nA. When the input voltage is about 0.5V or less from
V+, the NPN input stage is operating and the input bias
current is typically 18nA. Increases in temperature will
cause the voltage at which operation switches from the
PNPstagetotheNPNstagetomovetowardsV+. Theinput
offset voltage of the NPN stage is untrimmed and is
typically 600µV.
Distortion
There are two main contributors of distortion in op amps:
output crossover distortion as the output transitions from
sourcing to sinking current and distortion caused by
nonlinear common mode rejection. Of course, if the op
amp is operating inverting there is no common mode
induced distortion. When the LT1490 switches between
input stages there is significant nonlinearity in the CMRR.
Lower load resistance increases the output crossover
distortion, but has no effect on the input stage transition
distortion.ForlowestdistortiontheLT1490/LT1491should
be operated single supply, with the output always sourc-
ing current and with the input voltage swing between
ground and (V+ – 0.8V). See the Typical Performance
Characteristics curves.
A Schottky diode in the collector of each NPN transistor of
the NPN input stage allows the LT1490/LT1491 to operate
with either or both of its inputs above V+. At about 0.3V
aboveV+ theNPNinputtransistorisfullysaturatedandthe
input bias current is typically 4µA at room temperature.
The input offset voltage is typically 700µV when operating
above V+. The LT1490/LT1491 will operate with its inputs
44V above V– regardless of V+.
8
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LT1490/LT1491
W U U
APPLICATIO S I FOR ATIO
U
Gain
mance in single supply applications where the load is
returned to ground. The typical performance photo of
Open-Loop Gain for various loads shows the details.
The open-loop gain is almost independent of load when
the output is sourcing current. This optimizes perfor-
U
TYPICAL APPLICATIO S
Square Wave Oscillator
Optional Output Compensation for
Capacitive Loads Greater Than 200pF
59k
5V
100k
100k
V
IN
+
+
1/2 LT1490
1/2 LT1490
V
OUT
C
L
≤ 10,000pF
–
–
R
50k
C
1490/91 TA02
0.22µF
150Ω
0.1µF
1
2RC
f =
1490/91 TA04
V
= 5V WITH 5V SUPPLY
OUT
= 200µA
P-P
I
S
AT V = 5V, R = 50k, C = 1nF
S
OUTPUT IS 5kHz SLEW LIMITED TRIANGLE WAVE
W
W
SI PLIFIED SCHE ATIC
+
V
Q2
Q1
Q3
Q22
D1
D2
D3
R1
30k
R2
1k
Q19
Q4
–IN
+IN
Q17
Q18
Q20
OUT
Q7
Q8
Q11 Q12
R3
1k
+
Q16
2µA
Q15
Q9
Q10
Q13
Q14
Q21
R4
40k
R5
40k
Q5
Q6
D4
D5
–
V
ONE AMPLIFIER
1490/91 SS
9
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LT1490/LT1491
U
PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
MS Package
8-Lead Plastic MSOP
(LTC DWG # 05-08-1660)
0.118 ± 0.004*
(3.00 ± 0.102)
8
7
6
5
0.040 ± 0.006
(1.02 ± 0.15)
0.034 ± 0.004
(0.86 ± 0.102)
0.007
(0.18)
0° – 6° TYP
0.118 ± 0.004**
(3.00 ± 0.102)
SEATING
PLANE
0.193 ± 0.006
(4.90 ± 0.15)
0.012
(0.30)
REF
0.021 ± 0.006
(0.53 ± 0.015)
0.006 ± 0.004
(0.15 ± 0.102)
0.0256
(0.65)
BSC
MSOP (MS8) 1098
1
2
3
4
* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,
PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
N8 Package
8-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
0.400*
(10.160)
MAX
0.130 ± 0.005
0.300 – 0.325
0.045 – 0.065
(3.302 ± 0.127)
(1.143 – 1.651)
(7.620 – 8.255)
8
1
7
6
5
4
0.065
(1.651)
TYP
0.255 ± 0.015*
(6.477 ± 0.381)
0.009 – 0.015
(0.229 – 0.381)
0.125
0.020
(0.508)
MIN
(3.175)
MIN
+0.035
–0.015
2
3
0.325
0.018 ± 0.003
0.100
(2.54)
BSC
N8 1098
+0.889
8.255
(0.457 ± 0.076)
(
)
–0.381
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
0.010 – 0.020
(0.254 – 0.508)
7
5
8
6
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0°– 8° TYP
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
0.016 – 0.050
(0.406 – 1.270)
0.050
(1.270)
BSC
0.014 – 0.019
(0.355 – 0.483)
TYP
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
SO8 1298
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
1
3
4
2
10
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LT1490/LT1491
U
PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
N Package
14-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
0.770*
(19.558)
MAX
14
13
12
11
10
9
8
7
0.255 ± 0.015*
(6.477 ± 0.381)
1
2
3
5
6
4
0.300 – 0.325
(7.620 – 8.255)
0.045 – 0.065
(1.143 – 1.651)
0.130 ± 0.005
(3.302 ± 0.127)
0.020
(0.508)
MIN
0.065
(1.651)
TYP
0.009 – 0.015
(0.229 – 0.381)
+0.035
0.325
0.005
(0.125)
MIN
–0.015
0.125
(3.175)
MIN
0.018 ± 0.003
+0.889
8.255
(0.457 ± 0.076)
0.100
(
)
–0.381
(2.54)
BSC
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
N14 1098
S Package
14-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.337 – 0.344*
(8.560 – 8.738)
13
12
11
10
8
14
9
0.228 – 0.244
0.150 – 0.157**
(5.791 – 6.197)
(3.810 – 3.988)
1
2
3
4
5
6
7
0.010 – 0.020
(0.254 – 0.508)
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0° – 8° TYP
0.050
(1.270)
BSC
0.014 – 0.019
(0.355 – 0.483)
TYP
0.016 – 0.050
(0.406 – 1.270)
S14 1298
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
11
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LT1490/LT1491
U
TYPICAL APPLICATIO
Ring-Tone Generator
60V
R16
100k
R2
47k
Q1
R3
R5
IRF628
R6
10k
Q3
2N3904
10k
100k
C3
C2
0.047µF
0.47µF
R17
620Ω
Z1
15V
100k
5
R9
300k
R11
+
10k
10
3
2
7
D1
1N4148
1/4 LT1491
+
+
1
6
8
R1
33k
1/4 LT1491
1/4 LT1491
–
4
13
12
R7
16k
–
9
C4
0.068µF
–
–
14
C7
R18
1/4 LT1491
100Ω
+
R26
2k
R24
420
R23
4.7k
R12
10k
R14
10k
R4
R8
620k
C1
1µF
11
47µF
R10
620k
1.6M
SMOOTHING FILTER
OPTO1*
R25
4.7k
R13
130k
R15
47k
C5
0.01µF
CADENCE OSCILLATOR
20Hz OSCILLATOR
Q5
2N3904
UP TO
LOAD TEN
PHONES
Z2
15V
R19
620Ω
Q4
2N3906
Q2
IRF9620
R21
150Ω
*LED OF OPTO1 ILLUMINATES WHEN THE PHONE IS OFF THE HOOK
SEE DESIGN NOTE DN134 FOR AN EXPLANATION OF THE CIRCUIT
C6
0.033µF
POWER AMPLIFIER
R20
100k
–180V
1490/1491 TA03
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
Input/Output Common Mode Includes Ground, 70µV V
LT1078/LT1079
Dual/Quad 55µA Max, Single Supply, Precision Op Amps
OS(MAX)
and 2.5µV/°C Drift (Max), 200kHz GBW, 0.07V/µs Slew Rate
LTC1152
Rail-to-Rail Input, Rail-to-Rail Output, Zero-Drift Amplifier
High DC Accuracy, 10µV V , 100nV/°C, 1MHz GBW,
OS(MAX)
1V/µs Slew Rate, Supply Current 2.2mA (Max), Single Supply,
Can Be Configured for C-LoadTM Operation
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Dual/Quad 17µA Max, Single Supply, Precison Op Amps
Input/Output Common Mode Includes Ground, 70µV V
OS(MAX)
and 4µV/°C Drift (Max), 85kHz GBW, 0.04V/µs Slew Rate
LT1366/LT1367
Dual/Quad Precision, Rail-to-Rail Input and Output Op Amps
Dual/Quad Micropower Rail-to-Rail Precision Op Amps
475µV V
500µV V
, 500V/mV A
, 400kHz GBW
OS(MAX)
OS(MAX)
VOL(MIN)
LT1490A/LT1491A
, Improved Version of the LT1490/LT1491
C-Load is a trademark of Linear Technology Corporation.
14901fb LT/LCG 0600 2K REV B • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 1996
Linear Technology Corporation
●
1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900
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●
FAX: (408) 434-0507 TELEX: 499-3977 www.linear-tech.com
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