LINER LT1881 Dual and quad rail-to-rail output, picoamp input precision op amp Datasheet

LT1881/LT1882
Dual and Quad
Rail-to-Rail Output,
Picoamp Input Precision Op Amps
U
FEATURES
DESCRIPTIO
■
The LT®1881 and LT1882 op amps bring high accuracy
input performance to amplifiers with rail-to-rail output
swing. Input bias currents and capacitive load driving
capabilities are superior to the similar LT1884 and LT1885
amplifiers, at the cost of a slight loss in speed. Input
offset voltage is trimmed to less than 50μV and the low
drift maintains this accuracy over the operating temperature range. Input bias currents are an ultralow 200pA
maximum.
■
■
■
■
■
■
■
■
■
Offset Voltage: 50μV Maximum (LT1881A)
Input Bias Current: 200pA Maximum (LT1881A)
Offset Voltage Drift: 0.8μV/°C Maximum
Rail-to-Rail Output Swing
Supply Range: 2.7V to 36V
Operates with Single or Split Supplies
Open-Loop Voltage Gain: 1 Million Minimum
1mA Maximum Supply Current Per Amplifier
Stable at AV = 1, CL = 1000pF
Standard Pinouts
U
APPLICATIO S
■
■
■
■
■
Thermocouple Amplifiers
Bridge Transducer Conditioners
Instrumentation Amplifiers
Battery-Powered Systems
Photo Current Amplifiers
The amplifiers work on any total power supply voltage
between 2.7V and 36V (fully specified from 5V to ±15V).
Output voltage swings to within 40mV of the negative
supply and 220mV of the positive supply make these
amplifiers good choices for low voltage single supply
operation.
Capacitive loads up to 1000pF can be driven directly in
unity-gain follower applications.
The dual LT1881 and LT1881A are available with standard
pinouts in S8 and PDIP packages. The quad LT1882 is in
a 14-pin SO package. For a higher speed device with
similar DC specifications, see the LT1884/LT1885.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
U
TYPICAL APPLICATIO
16-Bit Voltage Output DAC on ±5V Supply
TC VOS Distribution, Industrial Grade
5V
5V
PERCENT OF UNITS (%)
1.65k
+
LT1881
–
LT1634
4.096V
–5V
R1
RCOM
REF
ROFS
33pF
5V
DAC
–
LT1881
LTC®1597
+
VOUT
– 4.096V
TO 4.096V
26
24
22
20
18
16
14
12
10
8
6
4
2
0
VS = ±15V
40 N8 (1 LOT)
144 S8 (2 LOTS)
184 TOTAL PARTS
1 –0.9–0.8–0.7–0.6–0.5–0.4–0.3–0.2–0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
INPUT OFFSET VOLTAGE DRIFT (μV/°C)
1881/2 TA01a
–5V
1881/2 TA01
18812fa
1
LT1881/LT1882
W W
U
W
ABSOLUTE
AXI U RATI GS
(Note 1)
Supply Voltage (V + to V –) ....................................... 40V
Differential Input Voltage (Note 2) ......................... ±10V
Input Voltage .................................................... V + to V –
Input Current (Note 2) ........................................ ±10mA
Output Short-Circuit Duration (Note 3) ............ Indefinite
Operating Temperature Range (Note 4) .. – 40°C to 85°C
Specified Temperature Range (Note 5) ... – 40°C to 85°C
Maximum Junction Temperature .......................... 150°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
U
W
U
PACKAGE/ORDER I FOR ATIO
ORDER PART NUMBER
TOP VIEW
OUT A 1
8
V+
–IN A 2
7
OUT B
6
–IN B
+IN A 3
A
B
V– 4
5
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
LT1881CN8
LT1881IN8
LT1881CS8
LT1881IS8
LT1881ACN8
LT1881AIN8
LT1881ACS8
LT1881AIS8
+IN B
TJMAX = 150°C, θJA = 130°C/W (N8)
TJMAX = 150°C, θJA = 190°C/W (S8)
ORDER PART NUMBER
TOP VIEW
14 OUT D
OUT A 1
–IN A 2
A
D
12 +IN D
+IN A 3
V+ 4
+IN B 5
13 –IN D
LT1882CS
LT1882IS
11 V –
B
C
10 +IN C
–IN B 6
9
–IN C
OUT B 7
8
OUT C
S PACKAGE
14-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 150°C/W
S8 PART MARKING
1881
1881I
1881A
1881AI
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
Single supply operation VS = 5V, 0V; VCM = VS/2 unless otherwise noted. (Note 5)
SYMBOL
PARAMETER
VOS
Input Offset Voltage (LT1881A)
CONDITIONS
MIN
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
Input Offset Voltage (LT1881/LT1882)
ΔVOS/ΔT
Input Offset Voltage Drift
(Note 6)
ΔVOS/ΔTIME Long-Term Input Offset Voltage Stability
IOS
TYP
MAX
UNITS
25
50
85
110
μV
μV
μV
30
80
125
150
μV
μV
μV
0.3
0.3
0.8
0.8
μV/°C
μV/°C
μV/month
0.3
Input Offset Current (LT1881A)
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
Input Offset Current (LT1881/LT1882)
100
200
250
300
pA
pA
pA
150
500
600
700
pA
pA
pA
18812fa
2
LT1881/LT1882
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
Single supply operation VS = 5V, 0V; VCM = VS/2 unless otherwise noted. (Note 5)
SYMBOL
PARAMETER
IB
Input Bias Current (LT1881A)
CONDITIONS
MIN
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
Input Bias Current (LT1881/LT1882)
Input Noise Voltage
0.1Hz to 10Hz
TYP
MAX
UNITS
100
200
250
300
pA
pA
pA
150
500
600
700
pA
pA
pA
μVP-P
0.5
en
Input Noise Voltage Density
f = 1kHz
14
nV/√Hz
in
Input Noise Current Density
f = 1kHz
0.03
pA/√Hz
RIN
Input Resistance
Differential Mode
Common Mode
20
100
MΩ
GΩ
CIN
Input Capacitance
VCM
CMRR
PSRR
●
Input Voltage Range
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Large-Signal Voltage Gain
2
V–
1V < VCM < 4V
1.2V < VCM < 3.8V
V – = 0V, VCM = 1.5V
0°C < TA < 85°C, 2.7V < V + < 32V
TA = –40°C, 3V < V + < 32V
pF
V+
●
+ 1.0
V – + 1.2
106
104
128
●
dB
dB
106
106
132
132
dB
dB
●
●
Minimum Operating Supply Voltage
AVOL
●
●
RL = 10k; 1V < VOUT < 4V
– 1.0
V + – 1.2
2.4
2.7
V
V
V
500
350
1600
●
V/mV
V/mV
300
250
800
●
V/mV
V/mV
250
200
400
●
V/mV
V/mV
RL = 2k; 1V < VOUT < 4V
RL = 1k; 1V < VOUT < 4V
VOL
Output Voltage Swing Low
No Load
ISINK = 100μA
ISINK = 1mA
ISINK = 5mA
●
●
●
●
20
25
70
270
40
50
150
600
mV
mV
mV
mV
VOH
Output Voltage Swing High
(Referred to V +)
No Load
ISOURCE = 100μA
ISOURCE = 1mA
ISOURCE = 5mA
●
●
●
●
120
130
180
360
220
230
300
600
mV
mV
mV
mV
IS
Supply Current Per Amplifier
VS = 3V, 0V
0.45
0.65
0.85
1.2
mA
mA
0.5
0.65
0.9
1.4
mA
mA
0.5
0.70
1.0
1.5
mA
mA
15
15
30
30
mA
mA
0.35
1.0
MHz
●
VS = 5V, 0V
●
VS = 12V, 0V
●
●
●
ISC
Short-Circuit Current
VOUT Short to GND
VOUT Short to V +
GBW
Gain Bandwidth Product
f = 20kHz
Channel Separation
f = 1kHz
120
dB
Settling Time
0.01%, VOUT = 1.5V to 3.5V,
AV = –1, RL = 2k
30
μs
tS
18812fa
3
LT1881/LT1882
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
Single supply operation VS = 5V, 0V; VCM = VS/2 unless otherwise noted. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
SR +
Slew Rate Positive
AV = – 1
0.35
●
0.15
0.12
V/μs
V/μs
0.11
0.08
0.18
●
V/μs
V/μs
VOUT = 4VP-P
(Note 10)
8.75
6.35
14
●
kHz
kHz
(Note 7)
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
(Note 7)
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
Offset Voltage Match Drift
(Notes 6, 7)
●
Noninverting Bias Current Match
(LT1881A)
(Notes 7, 8)
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
Noninverting Bias Current Match
(LT1881/LT1882)
(Notes 7, 8)
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
ΔCMRR
Common Mode Rejection Match
(Notes 7, 9)
●
102
125
dB
ΔPSRR
Power Supply Rejection Match
(Notes 7, 9)
V – = 0V, VCM = 1.5V
0°C < TA < 85°C, 2.7V < V + < 32V
TA = –40°C, 3V < V + < 32V
●
104
104
126
126
dB
dB
SR –
FPBW
ΔVOS
Slew Rate Negative
Full-Power Bandwidth
Offset Voltage Match (LT1881A)
Offset Voltage Match (LT1881/LT1882)
ΔIB+
AV = – 1
MAX
UNITS
30
70
125
160
μV
μV
μV
35
125
175
235
μV
μV
μV
0.4
1.2
μV/°C
200
300
400
500
pA
pA
pA
250
700
900
1000
pA
pA
pA
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
Split supply operation VS = ±15V, VCM = 0V unless otherwise noted. (Note 5)
SYMBOL
PARAMETER
VOS
Input Offset Voltage (LT1881A)
CONDITIONS
MIN
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
Input Offset Voltage (LT1881/LT1882)
ΔVOS/ΔT
Input Offset Voltage Drift
(Note 6)
ΔVOS/ΔTIME Long-Term Input Offset Voltage Stability
IOS
TYP
MAX
UNITS
25
50
85
110
μV
μV
μV
30
80
125
150
μV
μV
μV
0.3
0.3
0.8
0.8
μV/°C
μV/°C
μV/month
0.3
Input Offset Current (LT1881A)
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
Input Offset Current (LT1881/LT1882)
150
200
250
300
pA
pA
pA
150
500
600
700
pA
pA
pA
18812fa
4
LT1881/LT1882
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
Split supply operation VS = ±15V, VCM = 0V unless otherwise noted. (Note 5)
SYMBOL
PARAMETER
IB
Input Bias Current (LT1881A)
CONDITIONS
MIN
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
Input Bias Current (LT1881/LT1882)
Input Noise Voltage
0.1Hz to 10Hz
TYP
MAX
UNITS
150
200
250
300
pA
pA
pA
150
500
600
700
pA
pA
pA
μVP-P
0.5
en
Input Noise Voltage Density
f = 1kHz
14
nV/√Hz
in
Input Noise Current Density
f = 1kHz
0.03
pA/√Hz
RIN
Input Resistance
Differential Mode
Common Mode
20
100
MΩ
GΩ
CIN
Input Capacitance
VCM
CMRR
+PSRR
–PSRR
●
●
●
Input Voltage Range
Common Mode Rejection Ratio
–13.5V < VCM < 13.5V
Positive Power Supply Rejection Ratio
V–
Negative Power Supply Rejection Ratio
V+
= 15V, VCM
Large-Signal Voltage Gain
+ 1.0
V – + 1.2
●
114
130
dB
132
dB
< 18V
●
110
= 0V; –1.5V < V –
< –18V
●
106
= –15V, VCM
pF
V+
●
= 0V; 1.5V < V +
RL = 10k; –13.5V < VOUT < 13.5V
– 1.0
V + – 1.2
132
±1.2
●
Minimum Operating Supply Voltage
AVOL
2
V–
V
V
dB
±1.35
V
1000
700
1600
●
V/mV
V/mV
175
125
420
●
V/mV
V/mV
90
65
230
●
V/mV
V/mV
RL = 2k; –13.5V < VOUT < 13.5V
RL = 1k; –12V < VOUT < 12V
VOL
Output Voltage Swing Low
(Referred to VEE)
No Load
ISINK = 100μA
ISINK = 1mA
ISINK = 5mA
●
●
●
●
20
25
70
270
40
50
150
600
mV
mV
mV
mV
VOH
Output Voltage Swing High
(Referred to VCC)
No Load
ISOURCE = 100μA
ISOURCE = 1mA
ISOURCE = 5mA
●
●
●
●
160
160
180
360
220
230
300
600
mV
mV
mV
mV
IS
Supply Current Per Amplifier
VS = ±15V
0.5
0.85
1.1
1.6
mA
mA
●
20
15
40
40
mA
mA
●
20
15
30
30
mA
mA
0.4
0.85
MHz
●
ISC
Short-Circuit Current
VOUT Short to V –
VOUT Short to V +
GBW
Gain Bandwidth Product
f = 20kHz
Channel Separation
f = 1kHz
120
dB
tS
Settling Time
0.01%, VOUT = – 5V to 5V,
AV = –1, RL = 2k
35
μs
SR +
Slew Rate Positive
AV = – 1
0.4
V/μs
V/μs
●
0.21
0.18
18812fa
5
LT1881/LT1882
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
Split supply operation VS = ±15V, VCM = 0V unless otherwise noted. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
SR –
Slew Rate Negative
AV = – 1
FPBW
ΔVOS
MIN
TYP
0.13
0.1
0.20
●
V/μs
V/μs
VOUT = 28VP-P
(Note 10)
1.47
1.13
2.25
●
kHz
kHz
(Note 5)
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
Offset Voltage Match Drift
(Notes 6, 7)
●
Noninverting Bias Current Match
(LT1881/LT1882)
(Notes 7, 8)
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
0°C < TA < 70°C
– 40°C < TA < 85°C
●
●
Full-Power Bandwidth
Offset Voltage Match (LT1881/LT1882)
Offset Voltage Match (LT1881A)
ΔIB+
Noninverting Bias Current Match
(LT1881A)
MAX
UNITS
42
125
175
235
μV
μV
μV
35
70
125
160
μV
μV
μV
μV/°C
0.4
1.1
240
700
900
1000
pA
pA
pA
200
300
400
500
pA
pA
pA
ΔCMRR
Common Mode Rejection Match
(Notes 7, 9)
●
110
125
dB
Δ+PSRR
Positive Power Supply Rejection Match
V – = – 15V, VCM = 0V,
1.5V < V + < 18V, (Notes 7, 9)
●
108
130
dB
Δ –PSRR
Negative Power Supply Rejection Match
V + = 15V, VCM = 0V,
– 1.5V < V – < – 18V, (Notes 7, 9)
●
104
130
dB
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: The inputs are protected by internal resistors and back-to-back
diodes. If the differential input voltage exceeds ±0.7V, the input current
should be limited externally to less than 10mA.
Note 3: A heat sink may be required to keep the junction temperature
below absolute maximum.
Note 4: The LT1881C, LT1882C, LT1881I and LT1882I are guaranteed
functional over the operating temperature range of – 40°C to 85°C.
Note 5: The LT1881C and LT1882C 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. The LT1881I and LT1882I are
guaranteed to meet specified performance from – 40°C to 85°C.
Note 6: This parameter is not 100% tested.
Note 7: Matching parameters are the difference between amplifiers
A and B in the LT1881; and between amplifiers A and D and B and C in the
LT1882.
Note 8: This parameter is the difference between the two noninverting
input bias currents.
Note 9: ΔCMRR and ΔPSRR are defined as follows: CMRR and PSRR are
measured in μV/V on each amplifier. The difference is calculated in μV/V
and then converted to dB.
Note 10: Full power bandwidth is calculated from the slew rate: FPBW =
SR/2πVP.
18812fa
6
LT1881/LT1882
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current per Amplifier vs
Supply Voltage
Slew Rate vs Supply Voltage
0.45
0.45
AV = –1
0.40
RISING
AV = –1
RISING
FALLING
0.20
0.15
0.30
0.25
0.15
0.10
0.05
0.05
4
8 12 16 20 24 28 32
TOTAL SUPPLY VOLTAGE (V)
FALLING
0.20
0.10
0
0
4
8 12 16 20 24 28 32
TOTAL SUPPLY VOLTAGE (V)
1881/2 G02
0
–2
–4
0.1%
0.01%
4
0.01%
0
–2
0.1%
0.01%
–4
–6
–8
–8
–10
0 5 10 15 20 25 30 35 40 45 50 55 60 65
SETTLING TIME (μs)
0.1%
2
–6
–10
1881/2 G03
GAIN BANDWIDTH PRODUCT (kHz)
2
25 50 75 100 125 150
TEMPERATURE (°C)
900
6
0.01%
0
Gain Bandwidth Product vs
Supply Voltage
VS = ±15V
AV = 1
8
OUTPUT STEP (V)
OUTPUT STEP (V)
0.1%
VS = ±5V
0.2
0
–50 –25
36
10
VS = ±15V
AV = –1
4
VS = ±15V
FALLING
Settling Time vs Output Step
10
6
0.3
1881/2 G02
Settling Time vs Output Step
8
VS = ±5V
0.1
0
36
SLEW RATE (V/μs)
SLEW RATE (V/μs)
0.25
VS = ±15V
RISING
0.4
0.35
0.30
850
125°C
800
25°C
750
–55°C
700
650
600
0 5 10 15 20 25 30 35 40 45 50 55 60 65
SETTLING TIME (μs)
1881/2 G04
0
4
8 12 16 20 24 28 32
TOTAL SUPPLY VOLTAGE (V)
1881/2 G05
Phase Margin vs Supply Voltage
36
1881/2 G06
Gain vs Frequency, AV = –1
60
Gain vs Frequency, AV = 1
10
10
0
0
–10
–10
58
–55°C
125°C
54
125°C
52
GAIN (dB)
56
GAIN (dB)
PHASE MARGIN (DEG)
SLEW RATE (V/μs)
0.5
AV = –1
0.40
0.35
0
Slew Rate vs Temperature
–20
VS = ±2.5V
50
VS = ±2.5V
VS = ±15V
–20
VS = ±15V
–30
–30
48
46
0
4
8 12 16 20 24 28 32
TOTAL SUPPLY VOLTAGE (V)
36
1881/2 G07
–40
1k
10k
100k
1M
FREQUENCY (Hz)
10M
100M
1881/2 G08
–40
1k
10k
100k
1M
FREQUENCY (Hz)
10M
100M
1881/2 G09
18812fa
7
LT1881/LT1882
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Gain vs Frequency with CLOAD,
AV = 1
Gain vs Frequency with CLOAD,
AV = –1
10
10
VS = ±15V
VS = ±15V
0
0
1500pF
1800pF
–10
GAIN (dB)
GAIN (dB)
1000pF
500pF
–20
–10
1000pF
–20
500pF
0pF
–30
–40
–30
1k
10k
100k
1M
FREQUENCY (Hz)
10M
–40
100M
0pF
1k
10k
100k
1M
FREQUENCY (Hz)
1881/2 G10
VOUT (20mV/DIV)
TIME (50μs/DIV)
1881/2 G12
1881/2 G15
TIME (2μs/DIV)
1881/2 G13
Small Signal Response, AV = 1,
RL = 2k
VOUT (20mV/DIV)
VOUT (20mV/DIV)
Small Signal Response, AV = –1,
CL = 1000pF
TIME (2μs/DIV)
Small Signal Response, AV = –1,
No Load
Large Signal Response, AV = 1
1881/2 G14
Small Signal Response, AV = 1,
CL = 500pF
VOUT (20mV/DIV)
VOUT (5V/DIV)
TIME (50μs/DIV)
100M
1881/2 G11
VOUT (5V/DIV)
Large Signal Response, AV = –1
10M
TIME (2μs/DIV)
1881/2 G16
TIME (2μs/DIV)
1881/2 G17
18812fa
8
LT1881/LT1882
U W
TYPICAL PERFOR A CE CHARACTERISTICS
200
150
40 N8 (1 LOT)
144 S8 (2 LOTS)
184 TOTAL PARTS
5
VS = ±15V
0
OFFSET VOLTAGE DRIFT (μV)
VS = ±15V
100
50
0
–50
–100
–60
–40 –20
0
20
40
OUTPUT OFFSET VOLTAGE (μV)
–200
–55 –35 –15
60
–15
N8 VS = ±15V
–30
5 25 45 65 85 105 125
TEMPERATURE (°C)
INPUT COMMON MODE RANGE (V)
INPUT BIAS CURRENT (pA)
0
200
400
600
140
V+ – 0
100
200
40
60
80 100 120
TIME AFTER POWER UP (s)
LT1881 Input Common Mode
Range vs Supply Voltage
VS = ±15V
VS = ±15V
400
20
0
1881/2 G20
150
600
S8 VS = 5V, ±15V
–20
LT1881 Input Bias Current vs
Temperature
1000
+IBIAS
50
0
–IBIAS
–50
–100
800
ΔVOS < 1mV
V+ – 0.5
85°C
V+ – 1.0
V+ – 1.5
–40°C
25°C
V – + 1.5
–40°C
25°C
V – + 1.0
V – + 0.5
85°C
1000
–20 –15 –10
–5
0
5
VCM (V)
10
15
20
–150
–40
–20
0
20
40
60
TEMPERATURE (°C)
LT1881 Input Common Mode
Voltage vs Temperature
OUTPUT VOLTAGE SWING (V)
2
1
VS = ±5V
–1
–2
–3
V+ – 0.5
RL = 2k
V+ – 1.0
AV = –1
TA = 25°C
V
– + 1.0
RL = 2k
V – + 0.5
RL = 10k
–4
V
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1881/2 G24
4
6
8
10 12
SUPPLY VOLTAGE (±V)
14
16
1
RL = 10k
3
2
LT1881 Output Saturation Voltage
vs Load Current (Output High)
V+ – 0
4
–5
–50
0
1881/2 G23
LT1881 Output Voltage Swing vs
Supply Voltage
5
0
80
V– + 0
1881/2 G22
1881/2 G21
INPUT COMMON MODE VOLTAGE (V)
–10
1881/2 G19
LT1881 Input Bias Current vs
Common Mode Voltage
800
N8 VS = 5V
–5
–25
–150
1881/2 G18
IBIAS (pA)
Warm-Up Drift vs Time
–+0
0
2
4
6 8 10 12 14 16 18 20
SUPPLY VOLTAGE (±V)
1881/2 G25
OUTPUT SATURATION VOLTAGE (V)
26
24
22
20
18
16
14
12
10
8
6
4
2
0
LT1881IS8 Voltage Offset vs
Temperature
VOLTAGE OFFSET (μV)
PERCENT OF UNITS (%)
LT1881 VOS Distribution,
TA = 25°C
VS = ±15V
VOD = 30mV
TA = 85°C
TA = 25°C
0.1
0.01
0.001
TA = –40°C
0.01
0.1
1
SOURCING LOAD CURRENT (mA)
10
1881/2 G26
18812fa
9
LT1881/LT1882
U W
TYPICAL PERFOR A CE CHARACTERISTICS
LT1881 Output Saturation Voltage
vs Load Current (Output Low)
LT1881 Output Short-Circuit
Current vs Temperature
60
56
52
48
44
40
36
32
28
24
20
16
12
8
4
0
– 55 –35 –15
TA = 85°C
0.1
TA = 25°C
TA = –40°C
0.01
0.001
0.001
0.1
1
0.01
SINKING LOAD CURRENT (mA)
10
AV = 1
VS = ±2.5V
VIN = ±5V
RIN = 10k
5 25 45 65 85 105 125
TEMPERATURE (°C)
LT1881 Open-Loop Gain and
Phase vs Frequency
70
VS = ±15V
175
VS = ±5V
LOOP GAIN (dB)
60
120
40
100
30
75
PHASE
20
50
10
25
LOOP GAIN
0
–10
–25
–20
–50
–30
1k
–20
10k
100k
1M
FREQUENCY (Hz)
–100
10M
–40
–60
–80
–100
–120
–140
10
Output Impedance vs Frequency
VS = ±15V
VS = ± 2.5V
850
AV = 100
650
1
PSSR (dB)
OUTPUT IMPEDANCE (Ω)
700
AV = 10
0.1
AV = 1
0.01
600
550
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
1881/2 G33
10k 100k 1M
FREQUENCY (Hz)
0.001
100
1k
10k
FREQUENCY (Hz)
100k
1881/2 G34
10M 100M
LT1881 PSRR vs Frequency
10
VS = ± 2.5V
1k
1881/2 G32
100
900
800
100
1881/2 G31
Gain Bandwidth Product vs
Temperature
750
VS = ±15V
AV = 10
150
50
0
10 100 1k 10k 100k 1M 10M100M
FREQUENCY (Hz)
1881 G29.tif
LT1881 Channel Separation vs
Frequency
PHASE (DEG)
LOOP GAIN (dB)
GND
SOURCING
1881/2 G30
GAIN BANDWIDTH PRODUCT (KHz)
VOUT
1881/2 G28
LT1881 Open-Loop Gain vs
Frequency
1
GND
SINKING
1881/2 G27
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
–10
–20
0.1
VIN
CHANNEL SEPARATION (dB)
VS = ±15V
VOD = 30mV
OUTPUT SHORT-CIRCUIT CURRENT (mA)
OUTPUT SATURATION VOLTAGE (V)
1
LT1881 Output Voltage vs Large
Input Voltage
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
–10
VS = ±15V
–PSSR
+PSSR
1
10
100
1k
10k
FREQUENCY (Hz)
100k
1M
1881/2 G35
18812fa
10
LT1881/LT1882
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Common Mode Rejection Ratio vs
Frequency
LT1881 Noise Voltage vs
Frequency
LT1881 0.1Hz to 10Hz Noise
120
NOISE VOLTAGE (0.2μV/DIV)
100
80
CMRR (dB)
NOISE VOLTAGE DENSITY (nV/VHz)
50
60
40
20
0
0.1
1
10 100 1k 10k
FREQUENCY (Hz)
100k
0
1M
5
10
15
1s/DIV
20
LT1881 Noise Current Density vs
Frequency
100
80
60
40
20
10
100
FREQUENCY (Hz)
10
10
100
1k
RS (Ω)
10k
100k
20
0
2000
4000
6000
8000
CAPACITIVE LOAD (pF)
10000
1881/2 G42
AV = –1
10
LT1881 Undistorted Output Swing
vs Frequency
100
1k
CAPACITIVE LOAD (pF)
10k
LT1881 THD + Noise vs Frequency
10
30
1
AV = –1
TA = 25°C
VS = ±15V
25
20
15
AV = –1
TA = 25°C
VS = ±2.5V
10
5
VS = ±15V
VIN = 2VP-P
0.1
0.01
AV = –1
0.001
AV = 1
0
0
AV = 1
15
1881/2 G41
THD + NOISE (%)
40
20
1881/2 G36
PEAK-TO-PEAK OUTPUT VOLTAGE (V)
60
1k
VS = ±15V
RL = 10k
0
10
1M
35
VS = ±15V
10
100
FREQUENCY (Hz)
5
1
120
80
5
LT1881 Overshoot vs Capacitive
Load
100
1000
VS = ±2.5V
10
25
LT1881 Series Output Resistance
vs Capacitive Load
AV = 1
TA = 25°C
15
30
1881/2 G39
100
20
1881/2 G38
1
0
1
25
1
OVERSHOOT (%)
120
TOTAL INPUT REFERRED NOISE (nV/√Hz)
NOISE CURRENT DENSITY (fA/√Hz)
140
30
0
30
1000
160
35
LT1881A Total Noise vs Source
Resistance
180
VS = ±15V
40
1881/2 G37
1881/2 G36
SERIES OUTPUT RESISTANCE (Ω)
25
VS = ±5V
AV = 1
45
1
10
FREQUENCY (kHz)
100
1881/2 G43
0.0001
10
100
1k
10k
FREQUENCY (Hz)
100k
1881/2 G44
18812fa
11
LT1881/LT1882
U W
TYPICAL PERFOR A CE CHARACTERISTICS
LT1881 Total Harmonic Distortion
+ Noise vs Output Voltage
Amplitude
LT1881 Open-Loop Gain
CHANGE IN INPUT OFFSET VOLTAGE
(20μV/DIV)
10
f = 1kHz
RF = RG = 10k
AV = –1
VS = ±2.5V
THD + NOISE (%)
1
AV = –1
VS = ±15V
0.1
AV = 2
VS = ±2.5V
0.01
RL = 10k
RL = 2k
RL = 50k
OUTPUT VOLTAGE (5V/DIV)
0.001
10m
1881 G46.tif
VS = ±15V
AV = 2
VS = ±15V
0.1
1
10
OUTPUT VOLTAGE AMPLITUDE (VP-P)
100
1881/2 G45
LT1881 Settling Time/
Output Step 0.01%
LT1881 Settling Time/
Output Step 0.01%
0.5mV/DIV
10V
10V
GND
GND
0.5mV/DIV
AV = 1
VS = ±15V
20μs/DIV
AV = 1
VS = ±15V
1881 G47.tif
LT1881 Gain vs Temperature
1881 G48.tif
LT1881 Gain vs Load Resistance
5.0
4.5
50μs/DIV
10.0
VS = ±5V
+AVOL (0V TO 10V)
4.0
– AVOL (0V TO –10V)
3.0
GAIN (V/μV)
GAIN (V/μV)
3.5
RL = 10k
2.5
2.0
0V TO 10V
0V TO –10V
1.5
1.0
1.0
RL = 2k
VS = ±15V
0.5
0
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1881/2 G49
0.1
0
5
10
15
20
25
LOAD RESISTANCE (kΩ)
30
1881/2 G50
18812fa
12
LT1881/LT1882
U
W
U
U
APPLICATIO S I FOR ATIO
The LT1881 dual and LT1882 quad op amps feature
exceptional input precision with rail-to-rail output swing.
The amplifiers are similar to the LT1884 and LT1885
devices. The LT1881 and LT1882 offer superior capacitive
load driving capabilities over the LT1884 and LT1885 in
low voltage gain configurations. Offset voltages are trimmed
to less than 50μV and input bias currents are less than
200pA on the “A” grade devices. Obtaining beneficial
advantage of these precision input characteristics depends upon proper applications circuit design and board
layout.
Preserving Input Precision
Preserving the input voltage accuracy of the LT1881/
LT1882 requires that the applications circuit and PC board
layout do not introduce errors comparable to or greater
than the 30μV offset. Temperature differentials across the
input connections can generate thermocouple voltages of
10’s of microvolts. PC board layouts should keep connections to the amplifier’s input pins close together and away
from heat dissipating components. Air currents across the
board can also generate temperature differentials.
The extremely low input bias currents, 150pA, allow high
accuracy to be maintained with high impedance sources
and feedback networks. The LT1881/LT1882’s low input
bias currents are obtained by using a cancellation circuit
on-chip. This causes the resulting IBIAS + and IBIAS – to be
uncorrelated, as implied by the IOS specification being
greater than the IBIAS. The user should not try to balance
the input resistances in each input lead, as is commonly
recommended with most amplifiers. The impedance at
either input should be kept as small as possible to minimize total circuit error.
PC board layout is important to insure that leakage currents do not corrupt the low IBIAS of the amplifier. In high
precision, high impedance circuits, the input pins should
be surrounded by a guard ring of PC board interconnect,
with the guard driven to the same common mode voltage
as the amplifier inputs.
Input Common Mode Range
The LT1881 and LT1882 outputs are able to swing nearly
to each power supply rail, but the input stage is limited to
operating between V – +1V and V + –1V. Exceeding this
common mode range will cause the gain to drop to zero;
however, no phase reversal will occur.
Input Protection
The inverting and noninverting input pins of the LT1881
and LT1882 have limited on-chip protection. ESD protection is provided to prevent damage during handling. The
input transistors have voltage clamping and limiting resistors to protect against input differentials up to 10V. Short
transients above this level will also be tolerated. If the input
pins can see a sustained differential voltage above 10V,
external limiting resistors should be used to prevent
damage to the amplifier. A 1k resistor in each input lead
will provide protection against a 30V differential voltage.
Capacitive Loads
The LT1881 and LT1882 can drive capacitive loads up to
1000pF in unity-gain. The capacitive load driving increases as the amplifier is used in higher gain configurations. Capacitive load driving may be increased by
decoupling the capacitance from the output with a small
resistance.
18812fa
13
LT1881/LT1882
U
PACKAGE DESCRIPTIO
N8 Package
8-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
.400*
(10.160)
MAX
8
7
6
5
1
2
3
4
.255 ± .015*
(6.477 ± 0.381)
.300 – .325
(7.620 – 8.255)
.008 – .015
(0.203 – 0.381)
(
+.035
.325 –.015
8.255
+0.889
–0.381
)
.045 – .065
(1.143 – 1.651)
.130 ± .005
(3.302 ± 0.127)
.065
(1.651)
TYP
.100
(2.54)
BSC
.120
.020
(3.048)
MIN
(0.508)
MIN
.018 ± .003
(0.457 ± 0.076)
N8 1002
NOTE:
1. DIMENSIONS ARE
INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
18812fa
14
LT1881/LT1882
U
PACKAGE DESCRIPTIO
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
.189 – .197
(4.801 – 5.004)
NOTE 3
.045 ±.005
.050 BSC
7
8
.245
MIN
5
6
.160 ±.005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
.030 ±.005
TYP
1
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
× 45°
(0.254 – 0.508)
.008 – .010
(0.203 – 0.254)
3
2
4
.053 – .069
(1.346 – 1.752)
.004 – .010
(0.101 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
.050
(1.270)
BSC
.014 – .019
(0.355 – 0.483)
TYP
NOTE:
1. DIMENSIONS IN
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
SO8 0303
S Package
14-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
.337 – .344
(8.560 – 8.738)
NOTE 3
.045 ±.005
.050 BSC
14
N
12
11
10
9
8
N
.245
MIN
.160 ±.005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
1
.030 ±.005
TYP
13
2
3
N/2
N/2
RECOMMENDED SOLDER PAD LAYOUT
1
.010 – .020
× 45°
(0.254 – 0.508)
.008 – .010
(0.203 – 0.254)
2
3
4
5
6
.053 – .069
(1.346 – 1.752)
.004 – .010
(0.101 – 0.254)
0° – 8° TYP
.016 – .050
(0.406 – 1.270)
NOTE:
1. DIMENSIONS IN
.014 – .019
(0.355 – 0.483)
TYP
7
.050
(1.270)
BSC
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
S14 0502
18812fa
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.
15
LT1881/LT1882
U
TYPICAL APPLICATIO
–50°C to 600°C Digital Thermometer Operates on 3.3V
VCC = 3.3V
RF
1k
R1
4k
R2
4k
VCC
–
RT
VCC
R3
1k
A2
1/2 LT1881
VREF
VCC
+IN
CLK
+
–IN
GND
–
10k
0.1%
A1
1/2 LT1881
+
10k
0.1%
LTC1287
1μF
DOUT
CS/SHDN
V
V = CC + 1.588mV/°C
2
RT: OMEGA F4132 1000Ω RTD
R1, R2, R3, RF: USE BI 698-3 2k × 8 RESISTOR NETWORK
1881/2 TA02
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1112/LT1114
Dual/Quad Picoamp Input Op Amp
VOS = 60μV Max
LT1167
Gain Programmable Instrumentation Amp
Gain Error = 0.08% Max
LT1677
Low Noise, Rail-to-Rail Precision Op Amp
en = 3.2nV/√Hz
LT1793
Low Noise JFET Op Amp
IB = 10pA Max
LT1880
SOT-23 Picoamp Input Precision Op Amp
150μV Max VOS, – 40°C to 85°C Operation Guaranteed, SOT-23 Package
LT1884/LT1885
Dual/Quad Picoamp Input Op Amp
3 Times Faster than LT1881/LT1882
LTC2050
Zero Drift Op Amp in SOT-23
VOS = 3μV Max, Rail-to-Rail Output
18812fa
16
Linear Technology Corporation
LT 0407 REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
© LINEAR TECHNOLOGY CORPORATION 2000