LT1490/LT1491
Dual and Quad
Micropower Rail-to-Rail
Input and Output Op Amps
U
FEATURES
■
■
■
■
■
■
■
■
■
■
■
■
■
DESCRIPTIO
Rail-to-Rail Input and Output
Single Supply Input Range: – 0.4V to 44V
µA/Amplifier Max
Micropower: 50µ
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
Gain Bandwidth Product: 200kHz
U
APPLICATIO S
■
■
■
■
■
Battery- or Solar-Powered Systems
Portable Instrumentation
Sensor Conditioning
Supply Current Sensing
Battery Monitoring
Micropower Active Filters
4mA to 20mA Transmitters
, LTC and LT are registered trademarks of Linear Technology Corporation.
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
amplifiers are reverse supply protected; they draw no current
for reverse supply up to 18V. The input range of the LT1490/
LT1491 includes both supplies and the output swings to both
supplies. Unlike most micropower op amps, the LT1490/
LT1491 can drive heavy loads; their rail-to-rail outputs drive
20mA. The LT1490/LT1491 are unity-gain stable and drive all
capacitive loads up to 10,000pF when optional 0.22µF and
150Ω compensation is used.
The LT1490/LT1491 have a unique input stage that operates 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 resistors protect the inputs for faults below the negative supply
up to 22V. There is no phase reversal of the output for inputs
22V below V – or 44V above V –, independent of V +.
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.
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.
U
TYPICAL APPLICATIO
Battery Monitor
RS
0.2Ω
CHARGER
VOLTAGE
RA
2k
RA'
2k
IBATT
+
A
1/4 LT1491
Q1
2N3904
–
C
1/4 LT1491
–
LOGIC
+
RB
2k
RB'
2k
LOAD
+
Q2
2N3904
–
+
+
RG
10k
VBATT = 12V
S1
IBATT =
LOGIC HIGH (5V) = CHARGING
LOGIC LOW (0V) = DISCHARGING
B
1/4 LT1491
V
VOUT
= OUT AMPS
(RS)(RG /RA)(GAIN) GAIN
D
1/4 LT1491
VOUT
–
10k
90.9k
S1 = OPEN, GAIN = 1
S1 = CLOSED, GAIN = 10
RA = RB
VS = 5V, 0V
1490/91 TA01
1
LT1490/LT1491
W W
W
AXI U
U
ABSOLUTE
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
NUMBER
TOP VIEW
OUT A
–IN A
8
1
2
V+
7
OUT B
6
–IN B
5
+IN B
A
+IN A
V–
3
B
4
MS8 PACKAGE
N8 PACKAGE
8-LEAD MSOP
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 250°C/ W (MS8)
TJMAX = 150°C, θJA = 130°C/ W (N8)
TJMAX = 150°C, θJA = 190°C/ W (S8)
LT1490CMS8
LT1490CN8
LT1490CS8
LT1490IN8
LT1490IS8
OUT A
1
–IN A
2
+IN A
3
V+
4
+IN B
5
–IN B
6
MS8 PART MARKING
OUT B
7
LTBB
S8 PART MARKING
ORDER PART
NUMBER
TOP VIEW
14 OUT D
A
D
LT1491CN
LT1491CS
LT1491IN
LT1491IS
13 –IN D
12 +IN D
11 V –
10 +IN C
B
C
9
– IN C
8
OUT C
N PACKAGE
S PACKAGE
14-LEAD PDIP 14-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 110°C/ W (N)
TJMAX = 150°C, θJA = 150°C/ W (S)
1490 1490I
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
VOS
PARAMETER
Input Offset Voltage
CONDITIONS
LT1490 N Package
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
LT1490 S Package
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
LT1491 N Package
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
VOS TC
Input Offset Voltage Drift
IOS
Input Offset Current
IB
2
TYP
220
MAX
800
1000
1100
UNITS
µV
µV
µV
220
950
1200
1300
1100
1350
1450
µV
µV
µV
µV
µV
µV
350
1450
1650
1750
µV
µV
µV
●
●
●
●
300
●
●
LT1490CMS8 Package, LT1491 S Package
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
●
●
0°C ≤ TA ≤ 70°C (Note 7)
–40°C ≤ TA ≤ 85°C (Note 7)
●
●
2
2
4
4
●
●
0.2
VCM = 44V (Note 4)
0.8
0.8
nA
µA
●
●
4
4
0.1
1
8
10
nA
µA
nA
Input Bias Current
Input Noise Voltage
MIN
VCM = 44V (Note 4)
VS = 0V
0.1Hz to 10Hz
µV/°C
µV/°C
µVP-P
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
en
in
Input Noise Voltage Density
Input Noise Current Density
f = 1kHz
f = 1kHz
RIN
Input Resistance
Differential
Common Mode, VCM = 0V to 44V
CIN
Input Capacitance
Input Voltage Range
Common Mode Rejection Ratio
(Note 4)
VCM = 0V to VCC – 1V
VCM = 0V to 44V
AVOL
Large-Signal Voltage Gain
VS = 3V, VO = 500mV to 2.5V, RL = 10k
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
VS = 5V, VO = 500mV to 4.5V, RL = 10k
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
VOH
ISC
PSRR
IS
GBW
SR
Output Voltage Swing Low
Output Voltage Swing High
Short-Circuit Current (Note 2)
MAX
50
0.03
6
4
17
11
●
0
●
●
84
80
98
98
200
133
100
400
250
200
1500
●
●
●
●
UNITS
nV/√Hz
pA/√Hz
MΩ
MΩ
44
pF
V
dB
dB
V/mV
V/mV
V/mV
V/mV
V/mV
V/mV
1500
VS = 3V, No Load
VS = 3V, ISINK = 5mA
●
●
22
250
50
450
mV
mV
VS = 5V, No Load
VS = 5V, ISINK = 5mA
VS = 5V, ISINK = 10mA
VS = 3V, No Load
VS = 3V, ISOURCE = 5mA
VS = 5V, No Load
VS = 5V, ISOURCE = 10mA
●
●
22
250
330
2.978
2.6
4.978
4.6
50
500
500
mV
mV
mV
V
V
V
V
●
●
●
●
2.95
2.55
4.95
4.30
VS = 3V, Short to GND
VS = 3V, Short to VCC
10
10
15
30
mA
mA
VS = 5V, Short to GND
VS = 5V, Short to VCC
15
15
25
30
mA
mA
84
98
2
dB
V
18
27
40
Power Supply Rejection Ratio
Minimum Operating Supply Voltage
VS = 2.5V to 12.5V, VCM = VO = 1V
Reverse Supply Voltage
Supply Current per Amplifier
(Note 5)
Gain Bandwidth Product
(Note 4)
IS = – 100µA per Amplifier
Slew Rate
(Note 6)
TYP
4.6
CMRR
VOL
MIN
●
●
●
●
f = 1kHz
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
110
100
90
180
●
●
AV = – 1, RL = ∞
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
0.035
0.031
0.030
0.06
●
●
2.5
50
55
V
µA
µA
kHz
kHz
kHz
V/µs
V/µs
V/µs
3
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
PARAMETER
CONDITIONS
VOS
Input Offset Voltage
LT1490 N, S Package
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
MIN
TYP
MAX
UNITS
250
1200
1400
1500
●
●
µV
µV
µV
LT1491 N Package
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
●
●
350
1250
1500
1600
µV
µV
µV
LT1490CMS8 Package, LT1491 S Package
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
●
●
400
1600
1850
1950
µV
µV
µV
0°C ≤ TA ≤ 70°C (Note 7)
– 40°C ≤ TA ≤ 85°C (Note 7)
●
●
3
3
6
6
µV/°C
µV/°C
VOS TC
Input Offset Voltage Drift
IOS
Input Offset Current
●
0.2
0.8
nA
IB
Input Bias Current
●
4
8
nA
Input Noise Voltage
0.1Hz to 10Hz
1
µVP-P
en
Input Noise Voltage Density
f = 1kHz
50
nV/√Hz
in
Input Noise Current Density
f = 1kHz
0.03
pA/√Hz
RIN
Input Resistance
Differential
Common Mode, VCM = – 15V to 14V
CIN
Input Capacitance
Input Voltage Range
6
17
15000
MΩ
MΩ
4.6
pF
●
– 15
CMRR
Common Mode Rejection Ratio
VCM = – 15V to 29V
●
80
98
29
dB
V
AVOL
Large-Signal Voltage Gain
VO = ±14V, RL = 10k
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
100
75
50
250
●
●
V/mV
V/mV
V/mV
±14.9
±14.5
±14.5
±14.978
±14.750
±14.670
VO
Output Voltage Swing
No Load
IOUT = ±5mA
IOUT = ±10mA
ISC
Short-Circuit Current (Note 2)
Short to GND
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
±20
±15
±10
±25
●
●
mA
mA
mA
VS = ±1.25V to ±22V
●
88
98
dB
PSRR
Power Supply Rejection Ratio
IS
Supply Current per Amplifier
●
●
50
●
GBW
SR
Gain Bandwidth Product
Slew Rate
f = 1kHz
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
AV = – 1, RL = ∞, VO = ±10V,
Measure at VO = ±5V
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
Note 1: Absolute Maximum Ratings are those values beyond which the
life of the device may be impaired.
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 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.
4
●
●
●
●
V
V
V
70
85
µA
µA
125
110
100
200
kHz
kHz
kHz
0.0375
0.07
V/µs
0.0330
0.0300
V/µs
V/µs
The LT1490I/LT1491I are guaranteed to meet specified performance from
– 40°C to 85°C.
Note 4: VS = 5V limits are guaranteed by correlation to VS = 3V and
VS = ±15V tests.
Note 5: VS = 3V limits are guaranteed by correlation to VS = 5V and
VS = ±15V tests.
Note 6: Guaranteed by correlation to slew rate at VS = ±15V and GBW
at VS = 3V and VS = ±15V tests.
Note 7: This parameter is not 100% tested.
LT1490/LT1491
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current vs Supply Voltage
TA = 125°C
60
TA = 25°C
50
40
TA = –55°C
30
20
10
0
5
0
10 15 20 25 30 35 40
TOTAL SUPPLY VOLTAGE (V)
400
6000
300
4000
200
100
TA = –55°C
TA = 25°C
0
–100
–200
–300
– 400
45
TA = – 55°C
0.01
0.1
1
SOURCING LOAD CURRENT (mA)
TA = 125°C
0.1
TA = 25°C
TA = – 55°C
0.01
0.1
1
SINKING LOAD CURRENT (mA)
2
7
8
50
40
30
9
10
1490 G07
OUTPUT HIGH
20
OUTPUT LOW
10
0
10 20 30 40 50 60 70 80 90 100
INPUT OVERDRIVE (mV)
Input Noise Current vs Frequency
0.35
INPUT NOISE CURRENT DENSITY (pA/√Hz)
INPUT NOISE VOLTAGE DENSITY (nV/√Hz)
4 5 6
TIME (SEC)
60
1490/91 G06
80
3
70
Noise Voltage Density
vs Frequency
70
60
50
40
30
1
80
0
10
VS = ± 2.5V
NO LOAD
90
1490/90 G05
0.1Hz to 10Hz Noise Voltage
44
1490/91 G03
100
1490/90 G04
0
4.4
5.2
5.6
4.8
COMMON MODE VOLTAGE (V)
Output Saturation Voltage
vs Input Overdrive
VS = ± 2.5V
VOD = 30mV
0.01
0.001
10
VS = ±2.5V
TA = 25°C
TA = 125°C
–10
4.0
5
OUTPUT SATURATION VOLTAGE (mV)
OUTPUT SATURATION VOLTAGE (V)
TA = 25°C
NOISE VOLTAGE (400nV/DIV)
OUTPUT SATURATION VOLTAGE (V)
1
TA = 125°C
0.01
0.001
10
Output Saturation Voltage
vs Load Current (Output Low)
VS = ± 2.5V
VOD = 30mV
TA = –55°C
20
1490/91 G02
Output Saturation Voltage
vs Load Current (Output High)
0.1
30
0
1
3
4
2
TOTAL SUPPLY VOLTAGE (V)
0
VS = 5V, 0V
2000
TA = 125°C
1490/91 G01
1
INPUT BIAS CURRENT (nA)
CHANGE IN INPUT OFFSET VOLTAGE (µV)
SUPPLY CURRENT PER AMPLIFIER (µA)
80
70
Input Bias Current
vs Common Mode Voltage
Minimum Supply Voltage
1
10
100
FREQUENCY (Hz)
1k
1490/91 G08
0.30
0.25
0.20
0.15
0.10
0.05
0
1
10
100
FREQUENCY (Hz)
1k
1490/91 G09
5
LT1490/LT1491
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Gain and Phase Shift
vs Frequency
Gain Bandwidth Product
vs Temperature
40
30
20
20
0
GAIN
10
–20
0
– 40
–10
– 60
–20
– 80
10
100
FREQUENCY (kHz)
200
VS = ±15V
180
VS = ±3V
160
50
25
0
75
TEMPERATURE (°C)
40
200
30
180
170
20
RL = 10k
f = 1kHz
160
COMMON MODE REJECTION RATIO (dB)
220
PHASE MARGIN (DEG)
GAIN BANDWIDTH PRODUCT (kHz)
50
GAIN BANDWIDTH
0
5
10 15 20 25 30 35 40
TOTAL SUPPLY VOLTAGE (V)
100
VS = ±15V
80
VS = ±1.5V
60
40
10
FREQUENCY (kHz)
PHASE MARGIN
250
40
30
20
NEGATIVE SUPPLY
10
0
–10
10
FREQUENCY (kHz)
1
100
1490/91 G15
Output Impedance vs Frequency
10k
VS = ±15V
VS = ± 2.5V
120
70
60
200
POSITIVE SUPPLY
50
100
50
GAIN BANDWIDTH
150
40
100
30
110
OUTPUT IMPEDANCE (Ω)
300
130
CHANNEL SEPARATION (dB)
VS = ± 2.5V
AV = –1
RF = RG = 100k
f = 1kHz
60
Channel Separation vs Frequency
80
PHASE MARGIN (DEG)
GAIN BANDWIDTH PRODUCT (kHz)
350
VS = ±2.5V
70
1490 G14
1490/91 G13
Gain Bandwidth Product and
Phase Margin vs Load Resistance
125
–20
1
45
100
PSRR vs Frequency
80
20
10
150
50
25
0
75
TEMPERATURE (°C)
1490/91 G12
120
240
190
0.04
–50 –25
125
100
CMRR vs Frequency
210
FALLING, VS = ±1.5V
1490/91 G11
60
230
FALLING, VS = ±15V
120
Gain Bandwidth Product and
Phase Margin vs Supply Voltage
PHASE MARGIN
RISING, VS = ±1.5V
0.08
0.06
140
1490/91 G10
250
RISING, VS = ±15V
0.10
220
100
–50 –25
–100
1000
–30
1
f = 1kHz
PHASE SHIFT (DEG)
GAIN (dB)
240
60
PHASE
40
80
POWER SUPPLY REJECTION RATIO (dB)
50
100
Slew Rate vs Temperature
0.12
SLEW RATE (V/µs)
VS = ±2.5V
GAIN BANDWIDTH PRODUCT (kHz)
70
60
260
100
90
80
70
60
1k
AV = 100
100
AV = 10
10
1
AV = 1
50
50
1
10
LOAD RESISTANCE (kΩ)
20
100
1490/91 G16
6
40
0.1
1
10
FREQUENCY (kHz)
100
1490/91 G17
0.1
0.1
1
10
FREQUENCY (kHz)
100
1490/91 G18
LT1490/LT1491
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Undistorted Output Swing
vs Frequency
35
10
VS = ±2.5V
0
–2
–4
–6
1
10
FREQUENCY (kHz)
50
40
AV = 1
AV = 2
AV = 10
AV = 5
30
10
20
40
60 80 100 120 140 160
SETTLING TIME (µs)
10
100
1000
CAPACITIVE LOAD (pF)
10000
1490/91 G19
1490/91 F20
1490/91 G21
Total Harmonic Distortion + Noise
vs Frequency
Total Harmonic Distortion + Noise
vs Load Resistance
Total Harmonic Distortion + Noise
vs Output Voltage
0.01
1
RL = 10k
VCM = HALF SUPPLY
f = 1kHz
1
VS = ±1.5V
VIN = ±1V
0.1
VS = 3V, 0V
VIN = 0.5V TO 2.5V
AV = –1
VS = ±1.5V
0.1
AV = 1
VS = 3V, 0V
VS = 3V, 0V
VIN = 0.2V TO 2.2V
AV = 1
1
0.1
FREQUENCY (kHz)
10
0.001
0.1
AV = –1
VS = 3V, 0V
0.001
10
1
LOAD RESISTANCE TO GROUND (kΩ)
1490/91 G22
Open-Loop Gain
AV = 1
VS = ±1.5V
0.01
0.01
AV = –1
0.001
0.01
10
VS = 3V TOTAL
AV = 1
VIN = 2VP-P AT 1kHz
THD + NOISE (%)
10
VS = 3V, 0V
VOUT = 2VP-P
VCM = 1.2V
RL = 50k
0.1
CHANGE IN INPUT OFFSET VOLTAGE
(100µV/DIV)
60
0
0
100
70
20
AV = –1
AV = 1
–10
THD + NOISE (%)
1
2
–8
0
0.1
10
80
AV = 1
4
VS = 5V, 0V
ISOURCE = 170µA
90
OVERSHOOT (%)
OUTPUT STEP (V)
OUTPUT SWING (VP-P)
15
100
AV = –1
6
20
Capacitive Load Handling,
Overshoot vs Capacitive Load
VS = ±15V
8
25
5
THD + NOISE (%)
10
DISTORTION ≤1%
VS = ±15V
30
Settling Time to 0.1%
vs Output Step
100
0
1
2
OUTPUT VOLTAGE (VP-P)
1490/91 G24
1490/91 G23
Large-Signal Response
3
Small-Signal Response
VS = ±15V
RL = 2k
RL = 10k
RL = 50k
–10V
0V
10V
OUTPUT VOLTAGE (5V/DIV)
1490/91 G25
VS = ±15V
AV = –1
1490/91 G26
VS = ±15V
AV = 1
1490/91 G27
7
LT1490/LT1491
U
W
U U
APPLICATIO S I FOR ATIO
Supply Voltage
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
voltages up to 18V. In the event a reverse battery condition
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.
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.
Output
The output voltage swing of the LT1490/LT1491 is affected by input overdrive as shown in the typical performance 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 capacitors 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
beyond V + with less than 1nA of leakage current, provided
that V + is less than 0.5V.
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
these amplifiers for larger capacitive loads, up to 10,000pF,
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
PNP stage to the NPN stage to move towards V +. The input
offset voltage of the NPN stage is untrimmed and is
typically 600µV.
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
above V + the NPN input transistor is fully saturated and the
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
The normally reverse-biased substrate diode from the
output to V – will cause unlimited currents to flow when the
output is forced below V –. If the current is transient and
limited to 100mA, no damage will occur.
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. For lowest distortion the LT1490/LT1491 should
be operated single supply, with the output always sourcing current and with the input voltage swing between
ground and (V + – 0.8V). See the Typical Performance
Characteristics curves.
LT1490/LT1491
U
W
U U
APPLICATIO S I FOR ATIO
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
+
VIN
1/2 LT1490
1/2 LT1490
VOUT
CL ≤ 10,000pF
–
–
R
50k
C
0.1µF
1490/91 TA02
0.22µF
150Ω
f= 1
2RC
VOUT = 5VP-P WITH 5V SUPPLY
IS = 200µA
1490/91 TA04
AT VS = 5V, R = 50k, C = 1nF
OUTPUT IS 5kHz SLEW LIMITED TRIANGLE WAVE
W
W
SI PLIFIED SCHE ATIC
V+
Q2
Q1
D1
R1
30k
Q3
Q22
D3
D2
R2
1k
Q4
Q19
– IN
Q17
Q7
R3
1k
+
Q8
Q11
OUT
Q12
Q16
+IN
2µA
Q6
Q18
Q15
Q9
Q5
Q20
D4
D5
Q10
Q13
Q14
R4
40k
Q21
R5
40k
V–
ONE AMPLIFIER
1490/91 SS
9
LT1490/LT1491
U
PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
MS Package
8-Lead Plastic MSOP
(LTC DWG # 05-08-1660)
0.040 ± 0.006
(1.02 ± 0.15)
0.007
(0.18)
0.118 ± 0.004*
(3.00 ± 0.102)
0.034 ± 0.004
(0.86 ± 0.102)
8
7 6
5
0° – 6° TYP
SEATING
PLANE 0.012
(0.30)
0.0256
REF
(0.65)
BSC
0.021 ± 0.006
(0.53 ± 0.015)
0.118 ± 0.004**
(3.00 ± 0.102)
0.193 ± 0.006
(4.90 ± 0.15)
0.006 ± 0.004
(0.15 ± 0.102)
MSOP (MS8) 1098
1
* 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
4
2 3
N8 Package
8-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
0.300 – 0.325
(7.620 – 8.255)
0.009 – 0.015
(0.229 – 0.381)
(
0.045 – 0.065
(1.143 – 1.651)
+0.889
8.255
–0.381
0.130 ± 0.005
(3.302 ± 0.127)
0.065
(1.651)
TYP
+0.035
0.325 –0.015
)
0.400*
(10.160)
MAX
8
7
6
5
1
2
3
4
0.255 ± 0.015*
(6.477 ± 0.381)
0.125
(3.175) 0.020
MIN
(0.508)
MIN
0.018 ± 0.003
(0.457 ± 0.076)
0.100
(2.54)
BSC
N8 1098
*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
× 45°
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
0.053 – 0.069
(1.346 – 1.752)
0°– 8° TYP
0.016 – 0.050
(0.406 – 1.270)
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
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
10
8
7
6
5
0.004 – 0.010
(0.101 – 0.254)
0.050
(1.270)
BSC
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
SO8 1298
1
2
3
4
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
1
2
3
4
5
6
7
0.255 ± 0.015*
(6.477 ± 0.381)
0.130 ± 0.005
(3.302 ± 0.127)
0.300 – 0.325
(7.620 – 8.255)
0.045 – 0.065
(1.143 – 1.651)
0.020
(0.508)
MIN
0.065
(1.651)
TYP
0.009 – 0.015
(0.229 – 0.381)
+0.035
0.325 –0.015
0.005
(0.125)
MIN 0.100
(2.54)
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
BSC
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
(
+0.889
8.255
–0.381
)
0.018 ± 0.003
(0.457 ± 0.076)
0.125
(3.175)
MIN
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)
14
13
12
11
10
9
8
0.228 – 0.244
(5.791 – 6.197)
0.150 – 0.157**
(3.810 – 3.988)
1
0.010 – 0.020
× 45°
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
2
3
4
5
6
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0° – 8° TYP
0.016 – 0.050
(0.406 – 1.270)
0.014 – 0.019
(0.355 – 0.483)
TYP
7
0.050
(1.270)
BSC
*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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
S14 1298
11
LT1490/LT1491
U
TYPICAL APPLICATIO
Ring-Tone Generator
60V
R16
100k
R2
47k
R3
10k
C2
0.47µF
3
+
R1
1/4 LT1491
33k 2
1
D1
1N4148
R5
100k
5
–
7
R9
300k
R7
16k
–
R11
10k
10
Z1
15V
100k
+
1/4 LT1491
C4
0.068µF
9
8
13
–
C1
1µF
R8
620k
CADENCE OSCILLATOR
R10
620k
R12
SMOOTHING FILTER 10k
R14
10k
R13
130k
R15
47k
20Hz OSCILLATOR
C5
0.01µF
+
R24
11 420
14
C7
47µF
R18
100Ω
R26
2k
R23
4.7k
OPTO1*
R25
4.7k
Q5
2N3904
Z2
15V
*LED OF OPTO1 ILLUMINATES WHEN THE PHONE IS OFF THE HOOK
SEE DESIGN NOTE DN134 FOR AN EXPLANATION OF THE CIRCUIT
R17
620Ω
4
–
1/4 LT1491
12
R4
1.6M
Q3
2N3904
C3
0.047µF
+
1/4 LT1491
6
Q1
IRF628
R6
10k
Q2
IRF9620
POWER AMPLIFIER
–180V
R20
100k
R19
620Ω
UP TO
LOAD TEN
PHONES
Q4
2N3906
R21
150Ω
C6
0.033µF
1490/1491 TA03
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1078/LT1079
Dual/Quad 55µA Max, Single Supply, Precision Op Amps
Input/Output Common Mode Includes Ground, 70µV VOS(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 VOS(MAX), 100nV/°C, 1MHz GBW,
1V/µs Slew Rate, Supply Current 2.2mA (Max), Single Supply,
Can Be Configured for C-LoadTM Operation
LT1178/LT1179
Dual/Quad 17µA Max, Single Supply, Precison Op Amps
Input/Output Common Mode Includes Ground, 70µV VOS(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
475µV VOS(MAX), 500V/mV AVOL(MIN), 400kHz GBW
LT1490A/LT1491A
Dual/Quad Micropower Rail-to-Rail Precision Op Amps
500µV VOS(MAX), Improved Version of the LT1490/LT1491
C-Load is a trademark of Linear Technology Corporation.
12
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417 ● (408) 432-1900
FAX: (408) 434-0507● TELEX: 499-3977 ● www.linear-tech.com
14901fb LT/LCG 0600 2K REV B • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 1996
工商网监
湘ICP备2023018690号
