LTC6081/LTC6082
Precision Dual/Quad
CMOS Rail-to-Rail Input/
Output Amplifiers
Description
Features
■
■
■
■
■
■
■
■
■
■
■
■
■
Maximum Offset Voltage: 70µV (25°C)
Maximum Offset Drift: 0.8µV/°C
Maximum Input Bias: 1pA (25°C) 40pA (TA ≤ 85°C)
Open Loop Voltage Gain: 120dB Typ
Gain Bandwidth Product: 3.6MHz
CMRR: 100dB Min
PSRR: 98dB Min
0.1Hz to 10Hz Noise: 1.3µVP-P
Supply Current: 330µA
Rail-to-Rail Inputs and Outputs
Unity Gain Stable
2.7V to 5.5V Operation Voltage
Dual LTC6081 in 8-Lead MSOP and 10-Lead DFN10
Packages; Quad LTC6082 in 16-Lead SSOP and DFN
Packages
The LTC®6081/LTC6082 are dual/quad low offset, low drift,
low noise CMOS operational amplifiers with rail-to-rail
input/output swing.
The 70µV maximum offset, 1pA input bias current, 120dB
open loop gain and 1.3µVP-P 0.1Hz to 10Hz noise make
it perfect for precision signal conditioning. The LTC6081/
LTC6082 features 100dB CMRR and 98dB PSRR.
Each amplifier consumes only 330µA of current on a 3V
supply. The 10-lead DFN has an independent shutdown
function that reduces each amplifier’s supply current
to 1µA.
LTC6081/LTC6082 is specified for power supply voltages
of 3V and 5V from –40°C to 125°C. The dual LTC6081 is
available in 8-lead MSOP and 10-lead DFN10 packages.
The quad LTC6082 is available in 16-lead SSOP and DFN
packages.
Applications
■
■
■
■
■
■
Photodiode Amplifier
Strain Gauge
High Impedance Sensor Amplifier
Microvolt Accuracy Threshold Detection
Instrumentation Amplifiers
Thermocouple Amplifiers
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
VOS Drift Histogram
Shock Sensor Amplifier (Accelerometer)
1G
2M
2M
3.9pF
3.9pF
+
1/2
LTC6081
VOUT = 109mV/g
BW ~ 2.2kHz
–
1M
V–
0.1µF
10k
1M
60812 TA01
NUMBER OF AMPLIFIERS (OUT OF 100)
8.2pF
MURATA
PKGS-00LD
770pF
0° SENSOR
30
V+ 0.1µF
47pF
25
LTC6081MS8
TA = –40°C TO 125°C
VS = 3V
VCM = 0.5V
20
15
10
5
0
–0.20
–0.10
0
0.10
VOSDRIFT (µV/°C)
0.20
0.30
60812 TA01b
60812fd
For more information www.linear.com/LTC6081
1
LTC6081/LTC6082
Absolute Maximum Ratings
(Note 1)
Total Supply Voltage (V+ to V–)....................................6V
Input Voltage....................................................... V– to V+
Output Short Circuit Duration (Note 2)............. Indefinite
Operating Temperature Range (Note 3)
LTC6081C, LTC6082C........................... –40°C to 85°C
LTC6081I, LTC6082I.............................. –40°C to 85°C
LTC6081H, LTC6082H......................... –40°C to 125°C
(H Temperature Range Not Available in DFN Package)
Specified Temperature Range (Note 4)
LTC6081C, LTC6082C............................... 0°C to 70°C
LTC6081I, LTC6082I.............................. –40°C to 85°C
LTC6081H, LTC6082H......................... –40°C to 125°C
Junction Temperature
DFN Packages.................................................... 125°C
All Other Packages............................................. 150°C
Storage Temperature Range
DFN Packages..................................... –65°C to 125°C
All Other Packages.............................. –65°C to 150°C
Lead Temperature (Soldering, 10 Sec)................... 300°C
pIN CONFIGURATION
TOP VIEW
OUTA
1
10 V+
–INA
2
9 OUTB
+INA
3
V–
4
SHDN_A
5
A
B
TOP VIEW
8 –INB
7 +INB
6 SHDN_B
DD PACKAGE
10-LEAD (3mm × 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 43°C/W
UNDERSIDE METAL CONNECTED TO V–
OUTA 1
–INA 2
+INA 3
V4–
1
16 OUTD
–INA
2
+INA
3
14 +IND
V+
4
13 V–
+INB
5
12 +INC
–INB
6
11 –INC
OUTB
7
10 OUTC
NC
8
9
B
C
15 –IND
NC
DHC PACKAGE
16-LEAD (5mm × 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 43°C/W
UNDERSIDE METAL CONNECTED TO V–
2
V+
OUTB
–INB
+INB
TOP VIEW
OUTA
D
B
8
7
6
5
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 200°C/W
TOP VIEW
A
A
OUTA
1
–INA
2
+INA
3
14 +IND
V+
4
13 V–
+INB
5
16 OUTD
A
B
D
C
15 –IND
12 +INC
–INB
6
11 –INC
OUTB
7
10 OUTC
NC
8
9
NC
GN PACKAGE
16-LEAD PLASTIC SSOP
TJMAX = 150°C, θJA = 110°C/W
60812fd
For more information www.linear.com/LTC6081
LTC6081/LTC6082
order information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING* PACKAGE DESCRIPTION
SPECIFIED TEMPERATURE RANGE
LTC6081CDD#PBF
LTC6081CDD#TRPBF
LCJP
10-Lead (3mm × 3mm) Plastic DFN
0°C to 70°C
LTC6081IDD#PBF
LTC6081IDD#TRPBF
LCJP
10-Lead (3mm × 3mm) Plastic DFN
–40°C to 85°C
LTC6081CMS8#PBF
LTC6081CMS8#TRPBF
LTCJN
8-Lead Plastic MSOP
0°C to 70°C
LTC6081IMS8#PBF
LTC6081IMS8#TRPBF
LTCJN
8-Lead Plastic MSOP
–40°C to 85°C
LTC6081HMS8#PBF
LTC6081HMS8#TRPBF
LTCJN
8-Lead Plastic MSOP
–40°C to 125°C
LTC6082CDHC#PBF
LTC6082CDHC#TRPBF
6082
16-Lead (5mm × 3mm) Plastic DFN
0°C to 70°C
LTC6082IDHC#PBF
LTC6082IDHC#TRPBF
6082
16-Lead (5mm × 3mm) Plastic DFN
–40°C to 85°C
LTC6082CGN#PBF
LTC6082CGN#TRPBF
6082
16-Lead Plastic SSOP
0°C to 70°C
LTC6082IGN#PBF
LTC6082IGN#TRPBF
6082I
16-Lead Plastic SSOP
–40°C to 85°C
LTC6082HGN#PBF
LTC6082HGN#TRPBF
6082H
16-Lead Plastic SSOP
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
60812fd
For more information www.linear.com/LTC6081
3
LTC6081/LTC6082
Electrical
Characteristics
The
● denotes the specifications which apply over the full operating
+
–
temperature range, otherwise specifications are at TA = 25°C. Test conditions are V = 3V, V = 0V, VCM = 0.5V unless otherwise noted.
C, I SUFFIXES
SYMBOL PARAMETER
VOS
Offset Voltage
CONDITIONS
MIN
LTC6081MS8, LTC6082GN
LTC6081MS8, LTC6082GN
LTC6081DD, LTC6082DHC
LTC6081DD, LTC6082DHC
VCM = 0.5V, 2.5V
VCM = 0.5V, 2.5V
VCM = 0.5V, 2.5V
VCM = 0.5V, 2.5V
ΔVOS ⁄ΔT Input Offset Voltage Drift
(Note 5)
IB
Input Bias Current
(Note 6)
IOS
Input Offset Current
en
Input Referred Noise
In
Input Noise Current Density
(Note 7)
●
●
TYP
–70
–90
–70
–90
●
–70
–90
MAX
70
90
UNITS
μV
μV
μV
μV
±0.2
±0.8
μV/°C
0.2
1
40
0.2
1
500
pA
pA
100
pA
pA
0.1
0.1
15
13
1.3
13
1.3
nV/√Hz
µVP-P
0.5
0.5
fA/√Hz
V–
●
70
90
70
90
TYP
±0.8
●
Input Common Mode Range
MIN
±0.2
●
Noise Density at f = 1kHz
Integrated Noise From 0.1Hz to 10Hz
H SUFFIX
MAX
V+
V–
V+
V
CDIFF
Differential Input Capacitance
3
3
pF
CCM
Common Mode Input
Capacitance
7
7
pF
CMRR
Common Mode Rejection
Ratio
PSRR
VCM = 0V to 1.5V
VCM = 0V to 1.5V
VCM = 0V to 3V
VCM = 0V to 3V
Power Supply Rejection Ratio VS = 2.7V to 5.5V
●
95
88
93
88
105
100
105
100
95
86
93
86
105
100
105
100
dB
dB
dB
dB
98
96
110
98
96
110
●
dB
dB
–32
–320
1
mV
mV
mV
●
Output Voltage, High, Either
Output Pin
No Load
ISOURCE = 0.5mA
ISOURCE = 5mA
●
●
Output Voltage, Low, Either
Output Pin (Referred to V–)
No Load
ISINK = 0.5mA
ISINK = 5mA
●
●
AVOL
Large-Signal Voltage Gain
RLOAD = 10k, 0.5V < VOUT < 2.5V
●
110
ISC
Output Short-Circuit Current
Source
Sink
●
●
17
17
SR
Slew Rate
AV = 1
GBW
Gain-Bandwidth Product
(fTEST = 50kHz)
RL = 100k
VOUT
1
1
–35
–350
1
33
300
120
110
2.5
1.8
120
3.6
2.5
1.5
mV
mV
mV
dB
15
15
1
●
40
360
mA
mA
1
V/μs
3.6
MHz
MHz
F0
Phase Margin
RL = 10k
70
70
Deg
tS
Settling Time 0.1%
AV = 1, 1V Step
6
6
μs
IS
Supply Current
(Per Amplifier)
No Load
Shutdown Current
(Per Amplifier)
Shutdown, VSHDN ≤ 0.8V
Supply Voltage Range
Guaranteed by the PSRR Test
Channel Separation
fs = 10kHz, RL = 10k
VS
4
330
●
0.5
●
●
2.7
400
435
400
460
μA
μA
μA
μA
2
5.5
–120
330
2.7
5.5
–120
V
dB
60812fd
For more information www.linear.com/LTC6081
LTC6081/LTC6082
Electrical
Characteristics
The
● denotes the specifications which apply over the full operating
+
–
temperature range, otherwise specifications are at TA = 25°C. Test conditions are V = 3V, V = 0V, VCM = 0.5V unless otherwise noted.
C, I SUFFIXES
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
2
H SUFFIX
MAX
MIN
TYP
2
MAX
UNITS
V
V
Shutdown Logic
SHDN High
SHDN Low
THD
Total Harmonic Distortion
f = 10kHz, V+ = 3V, VOUT = 1VP-P , RL = 10k
–90
–90
dB
tON
Turn-On Time
VSHDN = 0.8V to 2V
10
10
µs
tOFF
Turn-Off Time
VSHDN = 2V to 0.8V
SHDN Pin Current
VSHDN = 0V
●
●
0.8
2
0.8
2
µs
2
●
μA
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Test
conditions are V+ = 5V, V– = 0V, VCM = 0.5V unless otherwise noted.
C, I SUFFIXES
SYMBOL PARAMETER
VOS
Offset Voltage
CONDITIONS
MIN
LTC6081MS8, LTC6082GN
LTC6081MS8, LTC6082GN
LTC6081DD, LTC6082DHC
LTC6081DD, LTC6082DHC
VCM = 0.5V
VCM = 0.5V
VCM = 0.5V
VCM = 0.5V
ΔVOS ⁄ΔT Input Offset Voltage Drift
(Note 8)
IB
Input Bias Current
IOS
Input Offset Current
en
Input Referred Noise
In
Input Noise Current Density
(Note 7)
●
●
TYP
–70
–90
–70
–90
±0.2
●
0.2
●
0.1
●
f = 1kHz
0.1Hz to 10Hz
Input Common Mode Range
MIN
70
90
70
90
–70
–90
±0.8
TYP
70
90
±0.2
0.2
40
0.1
15
MAX
UNITS
μV
μV
μV
μV
±0.8
μV/°C
500
pA
pA
100
pA
pA
13
1.3
13
1.3
nV/√Hz
µVP-P
0.5
0.5
fA/√Hz
V–
●
H SUFFIX
MAX
V+
V–
V+
V
CDIFF
Differential Input Capacitance
3
3
pF
CCM
Common Mode Input
Capacitance
7
7
pF
CMRR
Common Mode Rejection
Ratio
PSRR
VOUT
AVOL
VCM = 0V to 3.5V
VCM = 0V to 3.5V
VCM = 0V to 5V
Power Supply Rejection Ratio VS = 2.7V to 5.5V
●
●
100
95
86
110
110
95
100
94
86
110
110
95
dB
dB
dB
98
96
110
98
96
110
●
dB
dB
–24
–200
1
mV
mV
mV
Output Voltage, High, Either
Output Pin (Referred to V+)
No Load
ISOURCE = 0.5mA
ISOURCE = 5mA
●
●
Output Voltage, Low, Either
Output Pin (Referred to V–)
No Load
ISINK = 0.5mA
ISINK = 5mA
●
●
Large-Signal Voltage Gain
RLOAD = 10k, 0.5V < VOUT < 4.5V
●
1
1
110
120
–25
–220
1
27
210
110
120
32
240
mV
mV
mV
dB
60812fd
For more information www.linear.com/LTC6081
5
LTC6081/LTC6082
Electrical
Characteristics
The
● denotes the specifications which apply over the full operating
+
–
temperature range, otherwise specifications are at TA = 25°C. Test conditions are V = 5V, V = 0V, VCM = 0.5V unless otherwise noted.
C, I SUFFIXES
SYMBOL PARAMETER
CONDITIONS
MIN
ISC
Output Short-Circuit Current
Source
Sink
SR
Slew Rate
AV = 1
GBW
Gain-Bandwidth Product
(fTEST = 50kHz)
RL = 100k
F0
Phase Margin
RL = 10k
tS
Settling Time 0.1%
AV = 1, 1V Step
IS
Supply Current
(Per Amplifier)
No Load
Shutdown Current
(Per Amplifier)
Supply Voltage Range
VS
●
●
TYP
H SUFFIX
MAX
24
24
MIN
2.5
1.8
MAX
21
21
1
●
TYP
UNITS
mA
mA
1
V/μs
3.5
MHz
MHz
70
70
Deg
6
6
μs
3.5
340
2.5
1.5
●
425
465
Shutdown, VSHDN ≤ 1.2V
●
6
Guaranteed by the PSRR Test
●
2.7
●
●
3.5
5.5
340
425
490
μA
μA
μA
2.7
Channel Separation
fs = 10kHz, RL = 10k
SHDN High
SHDN Low
THD
Total Harmonic Distortion
f = 10kHz, V+ = 5V, VOUT = 2VP-P , RL = 10k
–90
–90
dB
tON
Turn-On Time
VSHDN = 1.2V to 3.5V
10
10
µs
tOFF
Turn-Off Time
VSHDN = 3.5V to 1.2V
2
2
µs
SHDN Pin Current
VSHDN = 0V
●
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: A heat sink may be required to keep the junction temperature
below the absolute maximum. This depends on the power supply voltage
and how many amplifiers are shorted.
Note 3: The LTC6081C/LTC6082C and LTC6081I/LTC6082I are guaranteed
functional over the operating temperature range of –40°C to 85°C.
The LTC6081H/LTC6082H are guaranteed functional over the operating
temperature range of –40°C to 125°C.
Note 4: The LTC6081C/LTC6082C are guaranteed to meet specified
performance from 0°C to 70°C. The LTC6081C/LTC6082C are designed,
–120
V
Shutdown Logic
6
–120
5.5
1.2
2
3.5
dB
1.2
V
V
μA
characterized and expected to meet specified performance from –40°C
to 85°C but are not tested or QA sampled at these temperatures. The
LTC6081I/LTC6082I are guaranteed to meet specified performance from
–40°C to 85°C. The LTC6081H/LTC6082H are guaranteed to meet specified
performance from –40°C to 125°C.
Note 5: Input offset drift is computed from the limits of the VOS test
divided by the temperature range. This is a conservative estimate of worst
case drift. Consult the Typical Performance Characteristics section for
more information on input offset drift.
Note 6: IB guaranteed by the VS = 5V test.
Note 7: Current noise is calculated from In = √2qIB , where q = 1.6 • 10–19
coulomb.
Note 8: VOS drift is guaranteed by the VS = 3V test.
60812fd
For more information www.linear.com/LTC6081
LTC6081/LTC6082
Typical Performance Characteristics
VOS Drift Histogram
25
20
15
10
5
0
–0.20
–0.10
0
0.10
VOSDRIFT (µV/°C)
20
10
5
–15
60812 G02
60812 G03
VOS vs VCM
140
100
80
0
4
–20
2
–30
0
–9.5
–40
–1.5
2.5
VOS (µV)
6.5
10.5
0
SOURCING CURRENT
–4
–20
0
0.5
1.0
1.5
2.0
VCM (V)
2.5
–40
3.0
SINKING
CURRENT
0
2
–2
OUTPUT CURRENT (mA)
4
VS = 3V
60812 G07
60812 G06
80
70
60
50
40
VS = 5V
VCM = 0.5V
30
20
0
5
90
0
–5
4
TA = 25°C
100
VS = 3V
VCM = 0.5V
10
6
3
Noise Voltage vs Frequency
10
5
2
110
VS = 5V
15
1
60812 G05
TA = 25°C
VCM = 0.5V
20
0
VCM (V)
NOISE VOLTAGE (nV/√Hz)
TA = 55°C
–6
0
25
TA = 125°C
50
–50
40
Warm-Up Drift vs Time
TA = 25°C
100
60
20
60812 G04
CHANGE IN OFFSET VOLTAGE (µV)
VS = 5V
VCM = 2.5V
VS = 5V
TA = 25°C
REPRESENTATIVE PARTS
120
10
VOS vs Output Current
VOS (µV)
–20
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
0.20
–10
6
–100
–0.10
0
0.10
VOSDRIFT (µV/°C)
20
8
150
–0.20
VS = 3V
TA = 25°C
REPRESENTATIVE PARTS
30
10
200
–5
40
12
–5.5
0
VOS vs VCM
VOS (µV)
NUMBER OF AMPS (OUT OF 100)
14
5
–10
60812 G01
LTC6081MS8
TA = 25°C
VS = 3V
VCM = 0.5V
16
15
10
VOS Histogram
18
LTC6081MS8
VS = 3V
VCM = 0.5V
REPRESENTATIVE PARTS
20
15
0
–0.30
0.30
0.20
25
LTC6081DFN
TA = –40°C TO 125°C
VS = 3V
VCM = 0.5V
VOS (µV)
25
VOS vs Temperature
VOS (µV)
LTC6081MS8
TA = –40°C TO 125°C
VS = 3V
VCM = 0.5V
NUMBER OF AMPS (OUT OF 100)
NUMBER OF AMPS (OUT OF 100)
30
VOS Drift Histogram
5 10 15 20 25 30 35 40 45 50 55 60
TIME AFTER POWER UP (s)
60812 G08
0
1
10
100
1k
FREQUENCY (Hz)
10k
100k
60812 G09
60812fd
For more information www.linear.com/LTC6081
7
LTC6081/LTC6082
Typical Performance Characteristics
0.1Hz to 10Hz Output
Voltage Noise
Noise Voltage vs Frequency
NMOS INPUTS
VCM = 2.5V
1
10
100
1k
FREQUENCY (Hz)
0
100k
10k
60812 G10
5
10 15 20 25 30 35 40 45 50
TIME (s)
0
40
IBIAS vs VCM
500
LTC6081MS8
VS = 5V
30
300
200
TA = 70°C
0
–10
40
60
80
100
TEMPERATURE (°C)
120
140
100
0
–100
–20
20
IBIAS (pA)
10
0.1
TA = 85°C
–200
–30
–300
–40
–400
–50
60812 G13
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
VCM (V)
–500
60812 G15
Small Signal Transient
Overshoot vs CL
55
50
45
TA = 25°C
VS = ±1.5V
RL = 10k
CL = 100pF
200µs/DIV
20mV/DIV
GND
60812 G16
TA = 25°C
VS = ±1.5V
RL = 10k
CL = 100pF
20µs/DIV
60812 G17
AV = 1
35
30
AV = 10
25
20
15
10
5
0
8
TA = 25°C
VS = 3V
VCM = 0.5V
40
OVERSHOOT (%)
GND
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
VCM (V)
0
60812 G14
Large Signal Transient
0.5V/DIV
LTC6081MS8
VS = 5V
TA = 125°C
400
20
100
1
10 15 20 25 30 35 40 45 50
TIME (s)
60812 G12
IBIAS vs VCM
VS = 5V
VCM = 2.5V
10
5
60812 G11
IBIAS (pA)
INPUT BIAS CURRENT (pA)
TA = 25°C
VS = 3V
VCM = 2.5V
OUTPUT NOISE (1µV/DIV)
PMOS INPUTS
VCM = 0.5V
Input Bias Current vs Temperature
1000
TA = 25°C
VS = 3V
VCM = 0.5V
VS = 3V
TA = 25°C
OUTPUT NOISE (500nV/DIV)
NOISE VOLTAGE (nV/√Hz)
300
280
260
240
220
200
180
160
140
120
100
80
60
40
20
0
0.1Hz to 10Hz Output
Voltage Noise
10
100
1000
CAPACITIVE LOAD (pF)
10000
60812 G18
60812fd
For more information www.linear.com/LTC6081
LTC6081/LTC6082
Typical Performance Characteristics
TA = 25°C
NO BYPASS CAPACITOR
VS = 5V
VS = 3V
330
310
290
270
1200
800
2
400
1
0
100
0
200
300
TIME (µs)
Open Loop Gain
INPUT VOLTAGE (µV)
RL = 2k
0
0.5
1.0
1.5
2.0
OUTPUT VOLTAGE (V)
2.5
3.0
RL = 100k
–10
RL = 10k
–20
RL = 2k
0
80
–180
GAIN
–40
100
–90
0
–20
VS = 5V
VCM = 0.5V
TA = 25°C
CL = 200pF
1k
10k
1M
100k
FREQUENCY (Hz)
10M
0
–90
0
–40
1k
10k
–270
1M
100k
FREQUENCY (Hz)
10M
VS = 5V
VCM = 0.5V
TA = 25°C
RL = 1k
60
40
80
60
40
20
–360
0
0
1k
10k 100k
1M
FREQUENCY (Hz)
60812 G24
10M
100M
60812 G26
VS = 5V
VCM = 0.5V
TA = 25°C
100
20
–20
100
–360
100M
PSRR vs Frequency
120
–270
–450
100M
60812 G25
–180
VS = 5V
VCM = 0.5V
TA = 25°C
PSRR (dB)
20
90
PHASE (DEG)
GAIN (dB)
40
RL = 10k
RL = 100k
CMRR (dB)
PHASE
20
CMRR vs Frequency
120
180
90
60812 G23
180
100M
270
GAIN
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT VOLTAGE (V)
Open Loop Gain vs Frequency
10M
PHASE
–20
0
10k 100k
1M
FREQUENCY (Hz)
RL = 10k
RL = 100k
40
60812 G22
60
1k
60
VS = 5V
TA = 25°C
0
–40
VS = 3V
VCM = 0.5V
TA = 25°C
60812 G21
–30
–30
AV = 1
PHASE (DEG)
RL = 10k
–20
0.1
Open Loop Gain vs Frequency
10
RL = 100k
–10
AV = 10
1
60812 G20
20
VS = 3V
TA = 25°C
0
AV = 100
10
0.01
100
Open Loop Gain
10
INPUT VOLTAGE (µV)
0
500
400
60812 G19
20
100
SUPPLY CURRENT
250
–40 –25 –10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
–40
3
SUPPLY VOLTAGE
1000
4
SUPPLY VOLTAGE (V)
350
Output Impedance vs Frequency
GAIN (dB)
370
SUPPLY CURRENT (µA)
1600
VCM = 0.5V
PER AMPLIFIER
SUPPLY CURRENT OPAMP (µA)
390
Supply Current vs Time
OUTPUT IMPEDANCE (Ω)
Supply Current vs Temperature
–20
100
1k
10k 100k
1M
FREQUENCY (Hz)
10M
100M
60812 G27
60812fd
For more information www.linear.com/LTC6081
9
LTC6081/LTC6082
Typical Performance Characteristics
Output Voltage Swing
vs Load Current
Channel Separation vs Frequency
CHANNEL SEPARATION (dB)
–20
–40
–60
–80
–100
–120
–140
100
1k
10k 100k
1M
FREQUENCY (Hz)
10M
100M
60812 G28
–20
+VS
VS = 3V
+VS –0.5 V = 0.5V
CM
+VS –1.0
SOURCE
–40
+VS –1.5
+VS –2.0
–VS 2.0
–VS 1.5
–VS 1.0
–VS 0.5
–VS 0
0.01
VS = 5V
AV = 1
RL = 10k
VOUT = 2VP-P
–30
DISTORTION (dBc)
VS = 3V
VCM = 0.5V
RL = 10k
OUTPUT VOLTAGE SWING (V)
(REFERRED TO SUPPLY VOLTAGE)
0
Distortion vs Frequency
TA = 125°C
TA = 25°C
TA = –55°C
–50
2ND
–60
3RD
–70
–80
SINK
1
10
0.1
LOAD CURRENT (mA)
–90
100
–100
1
60789 G29
10
100
FREQUENCY (kHz)
1000
60812 G30
Pin Functions
OUT: Amplifier Output
–IN: Inverting Input
+IN: Noninverting Input
V+: Positive Supply
V–: Negative Supply
SHDN_A: Shutdown Pin of Amplifier A, active low and only
valid for LTC6081DD. An internal current source pulls the
pin to V+ when floating.
SHDN_B: Shutdown Pin of Amplifier B, active low and only
valid for LTC6081DD. An internal current source pulls the
pin to V+ when floating.
NC: Not internally connected.
Exposed Pad: Connected to V–.
10
60812fd
For more information www.linear.com/LTC6081
LTC6081/LTC6082
Applications Information
Preserving Input Precision
Rail-to-Rail Input
Preserving input accuracy of the LTC6081/LTC6082 requires that the application circuit and PC board layout do
not introduce errors comparable or greater than the 5µV
typical offset of the amplifiers. Temperature differentials
across the input connections can generate thermocouple
voltages of 10’s of microvolts so the connections to the
input leads should be short, close together and away from
heat dissipating components. Air current across the board
can also generate temperature differentials.
The input stage of LTC6081/LTC6082 combines both PMOS
and NMOS differential pairs, extending its input common
mode voltage range to both positive and negative supply
voltages. At high input common mode range, the NMOS
pair is on. At low common mode range, the PMOS pair is
on. The transition happens when the common voltage is
between 1.3V and 0.9V below the positive supply. LTC6081
has better low frequency noise performance with PMOS
input on due to its lower flicker noise (see Voltage Noise
vs Frequency and 0.1Hz to 10Hz Input Voltage Noise in
Typical Performance Characteristics).
Capacitive Load
LTC6081/LTC6082 can drive capacitive load up to 200pF in
unity gain. The capacitive load driving capability increases
as the amplifier is used in higher gain configurations. A
small series resistance between the output and the load
further increases the amount of capacitance the amplifier
can drive.
SHDN Pins
Pins 5 and 6 are used for power shutdown on the LTC6081
in the DD package. If they are floating, internal current
sources pull Pins 5 and 6 to V+ and the amplifiers operate
normally. In shutdown, the amplifier output is high impedance, and each amplifier draws less than 2µA current.
Thermal Hysteresis
Figure 1 shows the input offset voltage hysteresis of the
LTC6081IMS8 for 3 thermal cycles from –45°C to 90°C.
The typical offset shift is ±4µV. The data was taken with
the ICs in stress free sockets. Mounting to PC boards
may cause additional hysteresis due to mechanical stress.
The LTC6081 will meet offset voltage specifications in the
electrical characteristics table even after 15µV of additional
error from thermal hysteresis.
0.30
PERCENTAGE OF UNITS
The extremely low input bias currents (0.1pA typical) allow high accuracy to be maintained with high impedance
sources and feedback resistors. Leakage currents on the
PC board can be higher than the input bias current. For
example, 10GΩ of leakage between a 5V supply lead and
an input lead will generate 500pA! Surround the input
leads with a guard ring driven to the same potential as the
input common mode voltage to avoid excessive leakage
in high impedance applications.
VOS CHANGE AFTER 3 THERMAL CYCLES
VCM = 0.5V
+
0.25 V = 3V
300 UNITS
0.20
0.15
0.10
0.5
0
–15 –12 –9 –6 –3 0 3 6
VOS CHANGE (µV)
9
12 15
60812 F01
Figure 1. VOS Thermal Hysteresis of LTC6081MS8
60812fd
For more information www.linear.com/LTC6081
11
LTC6081/LTC6082
Applications Information
PC Board Layout
Mechanical stress on a PC board and soldering-induced
stress can cause the VOS and VOS drift to shift. The DD
and DHC packages are more sensitive to stress. A simple
way to reduce the stress-related shifts is to mount the IC
near the short edge of the PC board, or in a corner. The
board edge acts as a stress boundary, or a region where
the flexure of the board is minimum. The package should
always be mounted so that the leads absorb the stress
and not the package. The package is generally aligned
with the leads perpendicular to the long side of the PC
board (see Figure 2).
The most effective technique to relieve the PC board stress
is to cut slots in the board around the op amp. These slots
can be cut on three sides of the IC and the leads can exit on
the fourth side. Figure 2 shows the layout of a LTC6081DD
with slots at three sides.
LONG DIMENSION
SLOTS
60812 F02
Figure 2. Vertical Orientation of LTC6081DD with Slots
Simplified Schematic
Simplified Schematic of the Amplifier
V+
R1
M10
R2
M11
M8
V–
VBIAS
D4
C1
+
I2
V+
–
I1
1µA
A1
M5
V+
+IN
V+
D3
V+
CLAMP
V–
D7
M1
OUTPUT
CONTROL
M6 M7
M2
D6
D8
–IN
V–
D5
D2
A2
+
V–
–
BIAS
GENERATION
SHDN
C2
D1
V–
NOTE: SHDN IS ONLY AVAILABLE
IN THE DFN10 PACKAGE
M3
M9
M4
R3
V–
12
OUT
R4
60812 SS
60812fd
For more information www.linear.com/LTC6081
LTC6081/LTC6082
Typical Applications
Low Side Current Sense
15pF
VDD
V+
I
100k
–
LOAD
1/2
LTC6081
+
RSH
1k
VOUT = RSH • I • 101
eNOISE = 3µVP-P, RTI
BW ~ 1kHz
60812 TA03
Two Op-Amp Instrumentation Amplifier
GAIN
TRIM
1.96k
100k
100k
V+ 0.1µF
CMRR
TRIM
976k
1M
–
50k
1/2
LTC6081
–
VIN
+
+
100k
–
1/2
LTC6081
VOUT = 1011 • VIN
+
V–
0.1µF
60812 TA04
60812fd
For more information www.linear.com/LTC6081
13
LTC6081/LTC6082
Typical Applications
Thermocouple Amplifier
5V 0.1µF
1M
+
1µF
1M
1/2
LTC6081
VOUT = 10mV/°C
0°C TO 500°C
–
5V
LT1025
2.49M
K
R–
10k
100pF
SENSOR: OMEGA 5TC-TT-K-30-36 K-TYPE THERMOCOUPLE
1M RESISTORS PROTECT CIRCUIT TO ±350V WITH NO PHASE REVERSAL OF AMPLIFIER OUTPUT
1pA MAX IBIAS TRANSLATES TO 0.05°C ERROR
60812 TA05
20µV VOS → 0.5°C OFFSET
Precision Nanoamp Bidirectional Current Source
VIN
100k
+
1/4
LTC6082
100Ω
–
1k
GAIN
TRIM
100Ω
0.01µF
5k
97.6k
100k
10-TURN
0.1µF
2.5V
10MΩ
+
1/4
LTC6082
–
IOUT = –1nA → 1nA FOR
VIN = –10V → 10V
TOTAL ERROR
工商网监
湘ICP备2023018690号
