LT1678CS8#TR [Linear]
LT1678 - Dual/Quad Low Noise, Rail-to-Rail, Precision Op Amps; Package: SO; Pins: 8; Temperature Range: 0°C to 70°C;型号: | LT1678CS8#TR |
厂家: | Linear |
描述: | LT1678 - Dual/Quad Low Noise, Rail-to-Rail, Precision Op Amps; Package: SO; Pins: 8; Temperature Range: 0°C to 70°C 运算放大器 放大器电路 光电二极管 |
文件: | 总16页 (文件大小:297K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
LT1678/LT1679
Dual/Quad Low Noise,
Rail-to-Rail, Precision Op Amps
U
FEATURES
DESCRIPTIO
The LT®1678/LT1679 are dual/quad rail-to-rail op amps
offering both low noise and precision: 3.9nV/√Hz wideband
noise, 1/f corner frequency of 4Hz and 90nV peak-to-peak
0.1Hz to 10Hz noise are combined with outstanding
precision: 100µV maximum offset voltage, greater than
100dB common mode and power supply rejection and
20MHz gain bandwidth product. The LT1678/LT1679 bring
precisionaswellaslownoisetosinglesupplyapplicationsas
low as 3V. The input range exceeds the power supply by
100mV with no phase inversion while the output can swing
to within 170mV of either rail.
■
Rail-to-Rail Input and Output
100% Tested Low Voltage Noise:
■
3.9nV/√Hz Typ at 1kHz
5.5nV/√Hz Max at 1kHz
■
Single Supply Operation from 2.7V to 36V
■
Offset Voltage: 100µV Max
■
Low Input Bias Current: 20nA Max
■
High AVOL: 3V/µV Min, RL = 10k
■
High CMRR: 100dB Min
High PSRR: 106dB Min
■
■
Gain Bandwidth Product: 20MHz
Operating Temperature Range: –40°C to 85°C
Matching Specifications
No Phase Inversion
8-Lead SO and 14-Lead SO Packages
■
The LT1678/LT1679 are offered in the SO-8 and SO-14
packages. A full set of matching specifications are also
provided, facilitating their use in matching dependent appli-
cations such as a two op amp instrumentation amplifier
design. The LT1678/LT1679 are specified for supply volt-
ages of ±15V, single 5V as well as single 3V. For a single
amplifier with similiar performance, see the LT1677 data
sheet.
■
■
■
U
APPLICATIO S
■
Strain Gauge Amplifiers
■
Portable Microphones
■
Battery-Powered Rail-to-Rail Instrumentation
, LTC and LT are registered trademarks of Linear Technology Corporation.
■
Low Noise Signal Processing
■
Microvolt Accuracy Threshold Detection
■
Infrared Detectors
U
TYPICAL APPLICATIO
Instrumentation Amplifier with Shield Driver
3
0.1Hz to 10Hz Voltage Noise
+
1k
30k
1
1/4
V
= ±2.5V
S
LT1679
–
2
R
F
15V
4
3.4k
5
6
GUARD
+
R
G
7
1/4
LT1679
100Ω
OUTPUT
30k
10
+
–
+
–
11
8
1/4
LT1679
R
G
INPUT
100Ω
9
–15V
–
GUARD
GAIN = 1000
0
2
4
6
8
10
R
F
13
12
–
TIME (sec)
3.4k
14
1/4
LT1679
16789 TA01
16789 TA01b
1k
+
sn16789 16789fs
1
LT1678/LT1679
W W
U W
ABSOLUTE AXI U RATI GS
(Note 1)
Lead Temperature (Soldering, 10 sec.)................. 300°C
Operating Temperature Range
Supply Voltage ...................................................... ±18V
Input Voltages (Note 2) ............ 0.3V Beyond Either Rail
Differential Input Current (Note 2) ..................... ±25mA
Output Short-Circuit Duration (Note 3)............ Indefinite
Storage Temperature Range ................. –65°C to 150°C
(Note 4)............................................. –40°C to 85°C
Specified Temperature Range
(Note 5)............................................. –40°C to 85°C
U W
U
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
ORDER PART
TOP VIEW
NUMBER
TOP VIEW
A
OUT A
–IN A
+IN A
1
2
3
4
5
6
7
14
13
12
11
10
9
OUT D
–IN D
+IN D
+
OUT A
1
2
3
4
8
7
6
5
V
A
B
D
C
LT1678CS8
LT1678IS8
LT1679CS
LT1679IS
OUT B
–IN B
+IN B
–IN A
+IN A
+
–
V
V
B
+IN B
–IN B
+IN C
–IN C
OUT C
–
V
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
OUT B
8
1678
1678I
TJMAX = 150°C, θJA = 190°C/ W
S PACKAGE
14-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 160°C/ W
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. VS = 3V, VCM = VO = 1.7V; VS = 5V, VCM = VO = 2.5V unless
otherwise noted.
SYMBOL
PARAMETER
CONDITIONS (Note 6)
MIN
TYP
MAX
UNITS
V
Input Offset Voltage
(Note 11)
35
55
75
100
270
350
µV
µV
µV
OS
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V =5V, V = V + 0.1V
150
180
200
550
750
1000
µV
µV
µV
S
CM
S
V =5V, V = V – 0.3V, 0°C ≤ T ≤ 70°C
●
●
S
CM
S
A
V =5V, V = V – 0.3V, –40°C ≤ T ≤ 85°C
S
CM
S
A
V =5V, V = –0.1V
1.5
1.8
2.0
30
45
50
mV
mV
mV
S
CM
V =5V, V = 0V, 0°C ≤ T ≤ 70°C
●
●
S
CM
A
V =5V, V = 0V, –40°C ≤ T ≤ 85°C
S
CM
A
∆V
∆Temp
Average Input Offset Drift (Note 10)
Input Bias Current
●
0.40
3
µV/°C
OS
I
(Note 11)
±2
±3
±7
±20
±35
±50
nA
nA
nA
B
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V = 5V, V = V + 0.1V
0.19
0.19
0.25
0.40
0.60
0.75
µA
µA
µA
S
CM
S
V = 5V, V = V – 0.3V, 0°C ≤ T ≤ 70°C
●
●
S
CM
S
A
V = 5V, V = V – 0.3V, –40°C ≤ T ≤ 85°C
S
CM
S
A
V = 5V, V = –0.1V
–5
–8.4
–10
–0.41
–0.45
–0.47
µA
µA
µA
S
CM
V = 5V, V = 0V, 0°C ≤ T ≤ 70°C
●
●
S
CM
A
V = 5V, V = 0V, –40°C ≤ T ≤ 85°C
S
CM
A
sn16789 16789fs
2
LT1678/LT1679
ELECTRICAL CHARACTERISTICS
otherwise noted.
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 3V, VCM = VO = 1.7V; VS = 5V, VCM = VO = 2.5V unless
SYMBOL
PARAMETER
CONDITIONS (Note 6)
MIN
TYP
MAX
UNITS
I
Input Offset Current
(Note 11)
4
5
8
25
35
55
nA
nA
nA
OS
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V = 5V, V = V + 0.1V
6
10
15
30
40
65
nA
nA
nA
S
CM
S
V = 5V, V = V – 0.3V, 0°C ≤ T ≤ 70°C
●
●
S
CM
S
A
V = 5V, V = V – 0.3V, –40°C ≤ T ≤ 85°C
S
CM
S
A
V = 5V, V = –0.1V
0.1
0.1
0.15
1.6
2.0
2.4
µA
µA
µA
S
CM
V = 5V, V = 0V, 0°C ≤ T ≤ 70°C
●
●
S
CM
A
V = 5V, V = 0V, –40°C ≤ T ≤ 85°C
S
CM
A
e
Input Noise Voltage
0.1Hz to 10Hz (Note 7)
90
nV
P-P
nV
P-P
nV
P-P
n
V
V
= V
180
CM
CM
S
= 0V
1600
Input Noise Voltage Density (Note 8)
f = 10Hz
4.4
6.6
19
nV/√Hz
nV/√Hz
nV/√Hz
O
V
V
= V , f = 10Hz
CM
CM
S O
= 0V, f = 10Hz
O
f = 1kHz
3.9
5.3
9
5.5
nV/√Hz
nV/√Hz
nV/√Hz
O
V
V
= V , f = 1kHz
CM
CM
S O
= 0V, f = 1kHz
O
i
Input Noise Current Density
Input Voltage Range
f = 10Hz
O
1.2
0.3
pA/√Hz
pA/√Hz
n
O
f = 1kHz
V
–0.1
0
V + 0.1V
S
V
V
CM
S
●
V – 0.3V
R
IN
Input Resistance
Common Mode
2
GΩ
C
Input Capacitance
4.2
pF
IN
CMRR
Common Mode Rejection Ratio
V = 5V, V = 1.9V to 3.9V
98
92
120
120
dB
dB
S
CM
V = 5V, V = 1.9V to 3.9V
●
●
●
S
CM
PSRR
Power Supply Rejection Ratio
Large-Signal Voltage Gain
V = 2.7V to 36V, V = V = 1.7V
100
98
125
120
dB
dB
S
CM
O
V = 3.1V to 36V, V = V = 1.7V
S
CM
O
A
V = 3V, R = 10k, V = 2.5V to 0.7V
0.6
0.3
3
2
V/µV
V/µV
VOL
S
L
O
V = 3V, R = 2k, V = 2.2V to 0.7V
0.5
0.4
0.4
3
0.9
0.8
V/µV
V/µV
V/µV
S
L
O
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V = 3V, R = 600Ω, V = 2.2V to 0.7V
0.20
0.15
0.10
0.43
0.40
0.35
V/µV
V/µV
V/µV
S
L
O
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V = 5V, R = 10k, V = 4.5V to 0.7V
1
0.6
0.3
3.8
2
2
V/µV
V/µV
V/µV
S
L
O
O°C < T < 70°C
●
●
A
–40 < T < 85°C
A
V = 5V, R = 2k, V = 4.2V to 0.7V
0.7
0.6
0.5
3.5
3.2
3.0
V/µV
V/µV
V/µV
S
L
O
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V = 5V, R = 600Ω, V = 4.2V to 0.7V
0.6
0.5
0.4
3.0
2.8
2.5
V/µV
V/µV
V/µV
S
L
O
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V
Output Voltage Swing Low (Note 11)
Above GND
SINK
OL
I
= 0.1mA
80
125
130
170
200
250
mV
mV
mV
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
sn16789 16789fs
3
LT1678/LT1679
ELECTRICAL CHARACTERISTICS
otherwise noted.
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 3V, VCM = VO = 1.7V; VS = 5V, VCM = VO = 2.5V unless
SYMBOL
PARAMETER
CONDITIONS (Note 6)
MIN
TYP
MAX
UNITS
V
Output Voltage Swing Low (Note 11)
Above GND
OL
I
= 2.5mA
170
195
205
250
320
350
mV
mV
mV
SINK
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
Above GND
I
= 10mA
370
440
465
600
720
770
mV
mV
mV
SINK
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V
Output Voltage Swing High (Note 11)
Below V
OH
S
I
= 0.1mA
A
75
85
93
150
200
250
mV
mV
mV
SOURCE
0°C ≤ T ≤ 70°C
–40°C ≤ T ≤ 85°C
●
●
A
Below V
S
I
= 2.5mA
A
110
195
205
250
350
375
mV
mV
mV
SOURCE
0°C ≤ T ≤ 70°C
–40°C ≤ T ≤ 85°C
●
●
A
Below V
S
I
= 10mA
A
170
200
230
400
500
550
mV
mV
mV
SOURCE
0°C ≤ T ≤ 70°C
●
●
–40°C ≤ T ≤ 85°C
A
I
Output Short-Circuit Current (Note 3)
Slew Rate (Note 13)
V = 3V
15
13
22
19
mA
mA
SC
S
●
●
V = 5V
S
18
14
29
25
mA
mA
SR
A = –1, R = 10k
4
3.5
3
6
5.8
5.5
V/µs
V/µs
V/µs
V
L
R = 10k, 0°C ≤ T ≤ 70°C
●
●
L
A
R = 10k, –40°C ≤ T ≤ 85°C
L
A
GBW
Gain Bandwidth Product (Note 11)
Settling Time
f = 100kHz
f = 100kHz
O
13
12.5
20
19
MHz
MHz
O
●
t
2V Step 0.1%, A = +1
2V Step 0.01%, A = +1
1.4
2.4
µs
µs
S
V
V
R
Open-Loop Output Resistance
Closed-Loop Output Resistance
I
= 0
OUT
V
100
1
Ω
Ω
O
A = 100, f = 10kHz
I
Supply Current per Amplifier (Note 12)
2
2.5
3.4
3.8
mA
mA
S
●
∆V
Offset Voltage Match
(Notes 11, 15)
35
55
75
150
400
525
µV
µV
µV
OS
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
∆IB+
Noninverting Bias Current Match
(Notes 11, 15)
±2
±3
±7
±30
±55
±75
nA
nA
nA
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
∆CMRR
∆PSRR
Common Mode Rejection Match
(Notes 11, 14, 15)
V = 5V, V = 1.9V to 3.9V
94
88
110
110
dB
dB
S
CM
●
●
Power Supply Rejection Match
(Notes 11, 14, 15)
V = 2.7V to 36V, V = V = 1.7V
96
94
120
120
dB
dB
S
CM
O
V = 3.1V to 36V, V = V = 1.7V
S
CM
O
sn16789 16789fs
4
LT1678/LT1679
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = ±15V, VCM = VO = 0V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS (Note 6)
MIN
TYP
MAX
UNITS
V
Input Offset Voltage
20
30
45
150
350
420
µV
µV
µV
OS
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
∆V
∆Temp
Average Input Offset Drift (Note 10)
Input Bias Current
●
0.40
3
µV/°C
OS
I
±2
±3
±7
±20
±35
±50
nA
nA
nA
B
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
I
Input Offset Current
3
5
8
25
35
55
nA
nA
nA
OS
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
e
Input Noise Voltage
0.1Hz to 10Hz (Note 7)
90
180
1600
nV
P-P
nV
P-P
nV
P-P
n
V
V
= 15V
= –15V
CM
CM
Input Noise Voltage Density
f = 10Hz
4.4
6.6
19
nV/√Hz
nV/√Hz
nV/√Hz
O
V
= 15V, f = 10Hz
= –15V, f = 10Hz
CM
CM
O
V
O
f = 1kHz
3.9
5.3
9
5.5
14
nV/√Hz
nV/√Hz
nV/√Hz
O
V
V
= 15V, f = 1kHz
= –15V, f = 1kHz
CM
CM
O
O
i
Input Noise Current Density
f = 10Hz
1.2
0.3
pA/√Hz
pA/√Hz
n
O
f = 1kHz
O
V
Input Voltage Range (Note 16)
Input Resistance
●
–13.3
V
GΩ
pF
CM
R
Common Mode
2
IN
C
Input Capacitance
4.2
IN
CMRR
Common Mode Rejection Ratio
V
= –13.3V to 14V
100
96
130
124
dB
dB
CM
●
●
PSRR
Power Supply Rejection Ratio
Large-Signal Voltage Gain
V = ±1.7V to ±18V
106
100
130
125
dB
dB
S
A
R = 10k, V = ±14V
0°C ≤ T ≤ 70°C
–40°C ≤ T ≤ 85°C
3
2
1
7
6
4
V/µV
V/µV
V/µV
VOL
L
O
●
●
A
A
R = 2k, V = ±13.5V
0.8
0.5
0.4
1.7
1.4
1.1
V/µV
V/µV
V/µV
L
O
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
sn16789 16789fs
5
LT1678/LT1679
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = ±15V, VCM = VO = 0V unless otherwise noted.
SYMBOL
V
PARAMETER
CONDITIONS (Note 6)
Above –V
MIN
TYP
MAX
UNITS
Output Voltage Swing Low
OL
S
I
= 0.1mA
110
125
130
200
230
260
mV
mV
mV
SINK
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
Above –V
S
I
= 2.5mA
170
195
205
280
350
380
mV
mV
mV
SINK
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
Above –V
S
I
= 10mA
370
440
450
600
700
750
mV
mV
mV
SINK
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
V
Output Voltage Swing High
Below +V
S
OH
I
= 0.1mA
80
90
100
150
200
250
mV
mV
mV
SOURCE
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
Below +V
S
I
= 2.5mA
A
110
120
120
200
300
350
mV
mV
mV
SOURCE
0°C ≤ T ≤ 70°C
–40°C ≤ T ≤ 85°C
●
●
A
Below +V
S
I
= 10mA
A
200
250
250
450
500
550
mV
mV
mV
SOURCE
0°C ≤ T ≤ 70°C
●
●
–40°C ≤ T ≤ 85°C
A
I
Output Short-Circuit Current (Note 3)
Slew Rate
20
15
35
28
mA
mA
SC
●
SR
R = 10k (Note 9)
4
3.5
3
6
5.8
5.5
V/µs
V/µs
V/µs
L
R = 10k (Note 9) 0°C ≤ T ≤ 70°C
●
●
L
A
R = 10k (Note 9) –40°C ≤ T ≤ 85°C
L
A
GBW
THD
Gain Bandwidth Product
f = 100kHz
f = 100kHz
O
13
12.5
20
19
MHz
MHz
O
●
Total Harmonic Distortion
Settling Time
R = 2k, A = 1, f = 1kHz, V = 20V
P-P
0.00025
%
L
V
O
O
t
10V Step 0.1%, A = +1
10V Step 0.01%, A = +1
2.7
3.9
µs
µs
S
V
V
R
O
Open-Loop Output Resistance
Closed-Loop Output Resistance
I
= 0
OUT
V
100
1
Ω
Ω
A = 100, f = 10kHz
I
Supply Current per Amplifier
2.5
3
3.5
4.5
mA
mA
S
●
Channel Separation
f = 10Hz, V = ±10V, R = 10k
132
dB
O
L
∆V
OS
Offset Voltage Match
(Note 15)
5
30
45
225
525
630
µV
µV
µV
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
∆IB+
Noninverting Bias Current Match
(Note 15)
±2
±3
±7
±30
±55
±75
nA
nA
nA
0°C ≤ T ≤ 70°C
●
●
A
–40°C ≤ T ≤ 85°C
A
∆CMRR
∆PSRR
Common Mode Rejection Match
(Notes 14, 15)
V
= –13.3V to 14V
96
92
120
115
dB
dB
CM
●
●
Power Supply Rejection Match
(Notes 14, 15)
V = ±1.7V to ±18V
100
96
123
120
dB
dB
S
sn16789 16789fs
6
LT1678/LT1679
ELECTRICAL CHARACTERISTICS
Note 1: Absolute Maximum Ratings are those values beyond which the life
Note 8: Noise is 100% tested at ±15V supplies.
of the device may be impaired.
Note 9: Slew rate is measured in A = –1; input signal is ±10V, output
V
measured at ±5V.
Note 10: This parameter is not 100% tested.
Note 2: The inputs are protected by back-to-back diodes. Current limiting
resistors are not used in order to achieve low noise. If differential input
voltage exceeds ±1.4V, the input current should be limited to 25mA. If the
common mode range exceeds either rail, the input current should be
limited to 10mA.
Note 3: A heat sink may be required to keep the junction temperature
below absolute maximum.
Note 11: V = 5V limits are guaranteed by correlation to V = 3V and
S
S
V = ±15V tests.
S
Note 12: V = 3V limits are guaranteed by correlation to V = 5V and
S
S
V = ±15V tests.
S
Note 13: Guaranteed by correlation to slew rate at V = ±15V and GBW at
S
Note 4: The LT1678C/LT1679C and LT1678I/LT1679I are guaranteed
functional over the Operating Temperature Range of –40°C to 85°C.
V = 3V and V = ±15V tests.
S
S
Note 14: ∆CMRR and ∆PSRR are defined as follows:
1. CMRR and PSRR are measured in µV/V on the individual amplifiers.
2. The difference is calculated between the matching sides in µV/V.
3. The result is converted to dB.
Note 15: Matching parameters are the difference between amplifiers A and
B on the LT1678 and between amplifiers A and D and B and C in the
LT1679.
Note 5: The LT1678C/LT1679C are guaranteed to meet specified
performance from 0°C to 70°C. The LT1678C/LT1679C are designed,
characterized and expected to meet specified performance from –40°C to
85°C but is not tested or QA sampled at these temperatures. The LT1678I/
LT1679I are guaranteed to meet specified performance from –40°C to
85°C.
Note 6: Typical parameters are defined as the 60% yield of parameter
distributions of individual amplifier; i.e., out of 100 LT1678/LT1679s,
typically 60 op amps will be better than the indicated specification.
Note 16: Input range guaranteed by the common mode rejection ratio test.
Note 7: See the test circuit and frequency response curve for 0.1Hz to10Hz
tester in the Applications Information section.
U W
TYPICAL PERFOR A CE CHARACTERISTICS
0.01Hz to 1Hz Voltage Noise
0.1Hz to 10Hz Voltage Noise
Voltage Noise vs Frequency
100
10
1
V
= ±15V
= 25°C
V
= 5V, 0V
V
= 5V, 0V
S
A
S
S
T
V
= 14.5V
CM
V
= 0V
CM
0
2
4
6
8
10
0
20
40
60
80
100
0.1
1
10
FREQUENCY (Hz)
100
1000
TIME (sec)
TIME (sec)
16789 G01
16789 G02
16789 G03
sn16789 16789fs
7
LT1678/LT1679
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Voltage Noise vs Temperature
Input Bias Current vs Temperature
Current Noise vs Frequency
6
5
4
3
2
1
10
16
14
12
10
8
V
V
= ±15V
CM
V
T
= ±15V
= 25°C
V
V
= ±15V
CM
S
S
A
S
= 0V
= 0V
10Hz
V
V
= 0V
CM
6
1
1kHz
4
2
= 14.5V
CM
0
–2
–4
–6
0.1
50
TEMPERATURE (°C)
100 125
–50 –25
0
25
75
–50
0
25
50
75 100 125
–25
0.01
0.1
1
10
FREQUENCY (kHz)
TEMPERATURE (°C)
16789 G05
16789 G06
16789 G04
Input Bias Current Over the
Common Mode Range
Offset Voltage Shift vs
Common Mode
Input Bias Current vs Temperature
1400
1200
1000
800
600
400
200
0
900
700
5
4
500
400
300
200
100
0
V
= ±15V
S
V
= –14V
V
= ±15V
= 25°C
CM
S
A
CURRENT OUT OF DUT
T
3
V
IS REFERRED TO
CM
500
OS
V
= 0V
2
V
= 14.5V
300
CM
V
CM
= –13.5V
1
100
INPUT BIAS CURRENT
0
–100
–300
–500
–700
–900
–1
–2
–3
–4
–5
–100
–200
–300
–400
–500
V
= 14.1V
CM
V
CM
= 14.7V
V
T
= ±1.5V TO ±15V
= 25°C
S
A
CURRENT INTO DUT
V
= –15.2V
–4
5 TYPICAL PARTS
+
CM
–
–50 –25
0
25
50
75 100 125
0
1.0
–16
–12
4
8
16
–1.0
V
2.0 –0.8 –0.4
V
0.4
–8
12
–
+
TEMPERATURE (°C)
COMMON MODE INPUT VOLTAGE (V)
V
– V (V)
V
– V (V)
CM
CM
16789 G09
16789 G07
16789 G08
V
OS vs Temperature of
Distribution of Input Offset
Voltage Drift (SO-8)
Representive Units
Warm-Up Drift vs Time
200
100
0
30
25
20
15
10
5
10
8
V
= 5V, 0V
S
A
V
V
= 5V, 0V
CM
S
V
= ±15V
= 25°C
S
A
T
= –40°C TO 85°C
= 0V
T
111 PARTS (2 LOTS)
SO PACKAGE
6
–100
–200
–300
4
2
0
0
–1.0
1.0
–3.0 –2.0
0
2.0
3.0
1
2
3
–55 –35 –15
5
25
45
65
85 105 125
0
4
INPUT OFFSET VOLTAGE DRIFT (µV/°C)
TEMPERATURE (°C)
TIME (min)
16789 G11
16789 G10
16789 G12
sn16789 16789fs
8
LT1678/LT1679
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Common Mode Rejection Ratio
vs Frequency
Common Mode Range vs
Temperature
Supply Current vs Supply Voltage
5
4
500
400
300
200
100
0
4.0
3.5
3.0
2.5
2.0
1.5
1.0
160
140
120
100
80
V
= ±2.5V TO ±15V
S
V
T
= ±15V
= 25°C
CM
S
A
V
= 0V
3
2
25°C
–55°C
1
T
= 125°C
A
–55°C
25°C
125°C
0
–1
–2
–3
–4
–5
–100
–200
–300
–400
–500
T
= 25°C
A
60
V
IS REFERRED TO
CM
OS
V
= 0V
40
T
= –55°C
A
125°C
20
0
–
–
1.0
–1.0
V
2.0 –0.8 –0.4
V
0.4
0
±5
±10
±15
±20
10k
100k
1M
10M
–
+
FREQUENCY (Hz)
SUPPLY VOLTAGE (V)
V
– V (V)
V
– V (V)
CM S
CM
S
16789 G14
16789 G15
16789 G09
Power Supply Rejection Ratio
vs Frequency
Voltage Gain vs Supply Voltage
% Overshoot vs Capacitive Load
10
60
50
40
30
20
10
0
160
140
120
100
80
V
= ±15V
= 2k TO 10k
= 1
V
T
= ±15V
= 25°C
S
L
S
A
R
A
R
= 10k
L
V
A
T
= 25°C
R
= 2k
L
NEGATIVE SUPPLY
1
RISING EDGE
60
POSITIVE SUPPLY
40
FALLING EDGE
T
= 25°C
A
L
20
R
TO GND
V
= V = V /2
CM
O S
0.1
0
100
0
0.001 0.01
0.1
1
10
1000
10
SUPPLY VOLTAGE (V)
30
20
10
100
CAPACITIVE LOAD (pF)
1000
FREQUENCY (kHz)
16789 G18
16789 G16
16789 G17
Phase Margin, Gain Bandwidth
Product and Slew Rate vs
Temperature
Small Signal
Large Signal
Transient Response
Transient Response
90
80
70
60
50
V
C
A
= ±15V
= 15pF
= –1
S
L
V
50mV
PHASE MARGIN
10V
R
= R = 1k
G
F
30
25
20
15
10
0V
GAIN BANDWIDTH PRODUCT
40
8
–10V
–50mV
+SR
–SR
6
A
V
= –1
A
V
C
= 1
VCL
5µs/DIV
0.5µs/DIV
VCL
S
= ±15V
= ±15V
S
L
= 15pF
4
16789 G20
16789 G21
–55 –35 –15
5
25 45 65 85 105 125
TEMPERATURE (°C)
16789 G19
sn16789 16789fs
9
LT1678/LT1679
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Settling Time vs Output
Step (Inverting)
Settling Time vs Output
Step (Noninverting)
Gain, Phase Shift vs Frequency
6
5
4
3
2
1
0
6
5
4
3
2
1
0
50
40
30
20
10
0
100
2k
5k
V
V
C
= ±15V
V
A
T
= ±15V
= –1
= 25°C
V
A
T
= ±15V
= 1
= 25°C
S
S
V
A
S
V
A
= 0V
5k
CM
PHASE
V
–
+
IN
–
+
= 10pF 80
L
V
V
2k
OUT
OUT
T
= –55°C
A
V
IN
T
= 25°C
A
R
= 1k
L
60
40
20
0
T
= 125°C
A
0.01% OF
FULL SCALE
0.01% OF
FULL SCALE
0.01% OF
FULL SCALE
0.01% OF
FULL SCALE
T
= 125°C
A
0.1% OF
FULL SCALE
GAIN
0.1% OF
FULL SCALE
T
= 25°C
A
0.1% OF
FULL SCALE
0.1% OF
FULL SCALE
T
= –55°C
A
–10
–20
–10 –8 –6 –4 –2
0
2
4
6
8
10
–10 –8 –6 –4 –2
0
2
4
6
8
10
0.1
1
10
100
OUTPUT STEP (V)
OUTPUT STEP (V)
FREQUENCY (MHz)
16789 G22
16789 G23
16789 G24
Output Voltage Swing vs
Load Current
Gain, Phase Shift vs Frequency
Gain, Phase Shift vs Frequency
100
80
60
40
20
0
+V
100
80
60
40
20
0
50
40
30
20
10
0
50
40
30
20
10
0
S
0
V
= ±15V
V
V
C
= ±15V
CM
= 10pF
V
V
C
= ±15V
CM
= 10pF
S
S
S
T
= –55°C
A
–0.1
–0.2
–0.3
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
= 14.7V
= –14V
T
= 125°C
L
L
A
T
= 25°C
T
= –55°C
A
PHASE
A
T
= 25°C
A
PHASE
T
= 125°C
A
T
= 125°C
T
= –55°C
A
A
T
= 125°C
A
T
= –55°C
A
T
= 25°C
A
T
= 125°C
= 25°C
A
GAIN
T
= 25°C
T
= 25°C
A
A
GAIN
T
A
T
= –55°C
A
T
= –55°C
A
–20
100
–20
–10
–10
–V
S
0.1
1
10
100
0.1
1
10
–10 –8 –6 –4 –2
0
2
4
6
8
10
FREQUENCY (MHz)
FREQUENCY (MHz)
OUTPUT CURRENT (mA)
16789 G25
16789 G26
16789 G27
Total Harmonic Distortion and
Noise vs Frequency for
Noninverting Gain
Total Harmonic Distortion and
Noise vs Frequency for
Noninverting Gain
Closed-Loop Output
Impedance vs Frequency
0.1
0.1
100
10
Z
= 2k/15pF
Z
= 2k/15pF
L
L
V
= ±15V
S
V
V
A
= ±15V
V
V
A
= ±15V
S
O
V
S
O
V
= 20V
= 20V
P-P
P-P
= 1, 10, 100
= –1, –10, –100
MEASUREMENT BANDWIDTH
= 10Hz TO 80kHz
MEASUREMENT BANDWIDTH
= 10Hz TO 80kHz
0.01
0.001
0.01
1
A
= –100
V
A
= 100
A
= 100
V
V
0.1
A
= 1
V
0.001
A
= –10
= –1
V
V
A
= 10
= 1
V
V
0.01
0.001
A
A
0.0001
0.0001
20
10
100
1k
10k
100k
1M
20
100
1k
10k
50k
100
1k
10k
50k
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
16789 G29
16789 G30
16789 G28
sn16789 16789fs
10
LT1678/LT1679
W U U
APPLICATIO S I FOR ATIO
U
Rail-to-Rail Operation
inputandacurrent, limitedonlybytheoutputshort-circuit
protection, will be drawn by the signal generator. With
RF ≥ 500Ω, the output is capable of handling the current
requirements (IL ≤ 20mA at 10V) and the amplifier stays
in its active mode and a smooth transition will occur.
To take full advantage of an input range that can exceed
thesupply, theLT1678/LT1679aredesignedtoeliminate
phase reversal. Referring to the photographs shown in
Figure 1, the LT1678/LT1679 are operating in the fol-
lower mode (AV = +1) at a single 3V supply. The output
of the LT1678/LT1679 clips cleanly and recovers with no
phasereversal. Thishasthebenefitofpreventinglock-up
inservosystemsandminimizingdistortioncomponents.
As with all operational amplifiers when RF > 2k, a pole will
be created with RF and the amplifier’s input capacitance,
creating additional phase shift and reducing the phase
margin.Asmallcapacitor(20pFto50pF)inparallelwithRF
will eliminate this problem.
R
F
Input = –0.5V to 3.5V
–
+
6V/µs
3
2
1
OUTPUT
LT1678
16789 F02
Figure 2. Pulsed Operation
Noise Testing
0
The 0.1Hz to 10Hz peak-to-peak noise of the LT1678/
LT1679 are measured in the test circuit shown (Figure 3).
The frequency response of this noise tester (Figure 4)
indicates that the 0.1Hz corner is defined by only one zero.
The test time to measure 0.1Hz to 10Hz noise should not
exceed ten seconds, as this time limit acts as an additional
zero to eliminate noise contributions from the frequency
band below 0.1Hz.
–0.5
16789 F01a
50µs/DIV
LT1678 Output
3
2
1
Measuring the typical 90nV peak-to-peak noise perfor-
mance of the LT1678/LT1679 requires special test pre-
cautions:
0
1. The device should be warmed up for at least five
minutes. As the op amp warms up, its offset voltage
changes typically 3µV due to its chip temperature
increasing 10°C to 20°C from the moment the power
suppliesareturnedon. Intheten-secondmeasurement
interval these temperature-induced effects can easily
exceed tens of nanovolts.
–0.5
16789 F01b
50µs/DIV
Figure 1. Voltage Follower with Input Exceeding the Supply
Voltage (VS = 3V)
Unity-Gain Buffer Application
When RF ≤ 100Ω and the input is driven with a fast, large-
signal pulse (>1V), the output waveform will look as
shown in the pulsed operation diagram (Figure 2).
2. For similar reasons, the device must be well shielded
from air currents to eliminate the possibility of
thermoelectric effects in excess of a few nanovolts,
which would invalidate the measurements.
During the fast feedthrough-like portion of the output, the
input protection diodes effectively short the output to the
sn16789 16789fs
11
LT1678/LT1679
W U U
U
APPLICATIO S I FOR ATIO
100
90
80
70
60
50
40
30
0.1µF
100k
10Ω
–
2k
*
+
22µF
LT1678
SCOPE
× 1
IN
4.3k
+
LT1001
4.7µF
R
= 1M
–
110k
2.2µF
VOLTAGE GAIN
100k
= 50,000
0.1µF
0.01
0.1
1
10
100
*DEVICE UNDER TEST
NOTE: ALL CAPACITOR VALUES ARE FOR
NONPOLARIZED CAPACITORS ONLY
24.3k
FREQUENCY (Hz)
16789 F03
16789 F04
Figure 4. 0.1Hz to 10Hz Peak-to-Peak
Noise Tester Frequency Response
Figure 3. 0.1Hz to 10Hz Noise Test Circuit
3. Sudden motion in the vicinity of the device can also
“feedthrough” to increase the observed noise.
Total Noise = [(op amp voltage noise)2 + (resistor noise)2
+ (current noise RS)2]1/2
Current noise is measured in the circuit shown in Figure 5
and calculated by the following formula:
Three regions can be identified as a function of source
resistance:
1/2
(i) R ≤ 400Ω. Voltage noise dominates
S
⎡
⎢
2⎤
)
2
)
− 130nV
e
•101
⎥
⎦
(
(
no
Resistor Noise
400Ω ≤ R ≤ 8k at 10Hz Dominates
(ii) 400Ω ≤ R ≤ 50k at 1kHz
S
⎣
i =
n
S
1MΩ 101
(
)(
)
(iii) R > 50k at 1kHz Current Noise
S
S
100k
R > 8k at 10Hz
Dominates
100Ω
500k
500k
Clearly the LT1678/LT1679 should not be used in region
(iii), where total system noise is at least six times higher
than the voltage noise of the op amp, i.e., the low voltage
noisespecificationiscompletelywasted. Inthisregionthe
LT1113 or LT1169 are better choices.
–
LT1678
e
no
+
16789 F05
Figure 5.
1000
R
V
= ±15V
= 25°C
S
A
T
The LT1678/LT1679 achieve their low noise, in part, by
operatingtheinputstageat100µAversusthetypical10µA
of most other op amps. Voltage noise is inversely propor-
tional while current noise is directly proportional to the
square root of the input stage current. Therefore, the
LT1678/LT1679’s current noise will be relatively high. At
low frequencies, the low 1/f current noise corner fre-
quency(≈200Hz)minimizescurrentnoisetosomeextent.
R
SOURCE RESISTANCE = 2R
100
10
1
AT 1kHz
AT 10Hz
RESISTOR
NOISE ONLY
0.1
1
10
100
In most practical applications, however, current noise will
not limit system performance. This is illustrated in the
Total Noise vs Source Resistance plot (Figure 6) where:
SOURCE RESISTANCE (kΩ)
16789 F06
Figure 6. Total Noise vs Source Resistance
sn16789 16789fs
12
LT1678/LT1679
W U U
APPLICATIO S I FOR ATIO
U
Rail-to-Rail Input
Rail-to-Rail Output
The input common mode range for the LT1678/LT1679
can exceed the supplies by at least 100mV. As the
common mode voltage approaches the positive rail (+VS
– 0.7V), the tail current for the input pair (Q1, Q2) is
reduced, which prevents the input pair from saturating
(refer to the Simplified Schematic). The voltage drop
across the load resistors RC1, RC2 is reduced to less than
200mV, degrading the slew rate, bandwidth, voltage
noise, offset voltage and input bias current (the cancella-
tion is shut off).
The rail-to-rail output swing is achieved by using transis-
tor collectors (Q28, Q29 referring to the Simplified Sche-
matic)insteadofcustomaryclassA-Bemitterfollowersfor
theoutputstage.TheoutputNPNtransistor(Q29)sinksthe
currentnecessarytomovetheoutputinthenegativedirec-
tion. The change in Q29’s base emitter voltage is reflected
directly to the gain node (collectors of Q20 and Q16). For
large sinking currents, the delta VBE of Q29 can dominate
the gain. Figure 7 shows the change in input voltage for a
change in output voltage for different load resistors con-
nected between the supplies. The gain is much higher for
outputvoltagesaboveground(Q28sourcescurrent)since
the change in base emitter voltage of Q28 is attenuated by
the gain in the PNP portion of the output stage. Therefore,
for positive output swings (output sourcing current) there
ishardlyanychangeininputvoltageforanyloadresistance.
Highestgainandbestlinearityareachievedwhentheoutput
is sourcing current, which is the case in single supply op-
erationwhentheloadisgroundreferenced.Figure8shows
gains for both sinking and sourcing load currents for a
worst-case load of 600Ω.
When the input common mode range goes below 1.5V
above the negative rail, the NPN input pair (Q1, Q2) shuts
off and the PNP input pair (Q8, Q9) turns on. The offset
voltage, input bias current, voltage noise and bandwidth
are also degraded. The graph of Offset Voltage Shift vs
Common Mode shows where the knees occur by display-
ing the change in offset voltage. The change-over points
aretemperaturedependent;seethegraphCommonMode
Range vs Temperature.
VOLTAGE GAIN SINGLE SUPPLY
V
= 5V
= 600Ω
S
L
R
R
= 600Ω
L
MEASURED ON TEKTRONIX 577
CURVE TRACER
R
= 1k
L
R
TO 0V
L
R
= 10k
L
INPUT VOLTAGE
(50µV/DIV)
INPUT VOLTAGE
(10µV/DIV)
R
TO 5V
L
T
= 25°C
= ±15V
CONNECTED TO 0V
A
S
V
R
L
MEASURED ON
TEKTRONIX 577
CURVE TRACER
–15 –10 –5
0
5
10 15
0
1
2
3
4
5
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
16789 F07
16789 F08
Figure 7. Voltage Gain Split Supply
Figure 8. Voltage Gain Single Supply
sn16789 16789fs
13
LT1678/LT1679
W
W
SI PLIFIED SCHE ATIC
+
+
sn16789 16789fs
14
LT1678/LT1679
U
PACKAGE DESCRIPTIO
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
.189 – .197
(4.801 – 5.004)
.045 ±.005
NOTE 3
.050 BSC
7
5
8
6
.245
MIN
.160 ±.005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
.030 ±.005
TYP
1
3
4
2
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
(0.254 – 0.508)
× 45°
.053 – .069
(1.346 – 1.752)
.004 – .010
(0.101 – 0.254)
.008 – .010
(0.203 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
.050
(1.270)
BSC
.014 – .019
(0.355 – 0.483)
TYP
NOTE:
INCHES
1. DIMENSIONS IN
(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 .150 Inch)
(Reference LTC DWG # 05-08-1610)
.337 – .344
.045 ±.005
(8.560 – 8.738)
.050 BSC
NOTE 3
14
N
13
12
11
10
9
8
N
1
.245
MIN
.160 ±.005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
2
3
N/2
N/2
.030 ±.005
TYP
RECOMMENDED SOLDER PAD LAYOUT
7
1
2
3
4
5
6
.010 – .020
(0.254 – 0.508)
× 45°
.053 – .069
(1.346 – 1.752)
.004 – .010
(0.101 – 0.254)
.008 – .010
(0.203 – 0.254)
0° – 8° TYP
.050
(1.270)
BSC
.014 – .019
(0.355 – 0.483)
TYP
.016 – .050
(0.406 – 1.270)
S14 0502
NOTE:
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
1. DIMENSIONS IN
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
sn16789 16789fs
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.
15
LT1678/LT1679
U
TYPICAL APPLICATIO
Bridge Reversal Eliminates 1/f Noise and Offset Drift of a Low Noise, Non-autozeroed, Bipolar Amplifier.
Circuit Gives 14nV Noise Level or 19 Effective Bits Over a 10mV Span
V
REF
3
V
7V
REF
4
φ1
5,6,7,8
LT1461-5
2
10µF
0.1µF
5V
+
100k
10Ω
1
1/2 LT1678
–
+
REF
0.047µF
350Ω
350Ω
350Ω
1k
0.1%
100Ω
+
IN
1µF
1µF
350Ω
100Ω
0.1%
LTC2440
1k
100Ω
0.1%
–
IN
–
0.047µF
–
REF
V
REF
3
10Ω
100k
1/2 LT1678
+
4
2
φ1
φ2
2X
SILICONIX
Si9801
φ2
5,6,7,8
1
≈2s
16789 TA02
RELATED PARTS
PART NUMBER
LT1028/LT1128
LT1115
DESCRIPTION
COMMENTS
Lowest Noise 0.85nV/√Hz
Ultralow Noise Precision Op Amps
Ultralow Noise, Low distortion Audio Op Amp
0.002% THD, Max Noise 1.2nV/√Hz
Similar to LT1007
LT1124/LT1125
LT1126/LT1127
LT1226
Dual/Quad Low Noise, High Speed Precision Op Amps
Dual/Quad Decompensated Low Noise, High Speed Precision Op Amps
Low Noise, Very High Speed Op Amp
Similar to LT1037
1GHz, 2.6nV/√Hz, Gain of 25 Stable
Precision C-LoadTM Stable
Rail-to-Rail 3.2nV/√Hz
LT1498/LT1499
LT1677
10MHz, 5V/µs, Dual/Quad Rail-to-Rail Input and Output Op Amps
Single Version of LT1678/LT1679
LT1792
Low Noise, Precision JFET Input Op Amp
4.2nV/√Hz, 10fA/√Hz
LT1793
Low Noise, Picoampere Bias Current Op Amp
6nV/√Hz, 1fA/√Hz, I = 10pA Max
B
LT1806
Low Noise, 325MHz Rail-to-Rail Input and Output Op Amp
Dual/Quad Rail-to-Rail Output Picoamp Input Precision Op Amps
Dual/Quad Rail-to-Rail Output Picoamp Input Precision Op Amps
3.5nV/√Hz
LT1881/LT1882
LT1884/LT1885
C
to 1000pF, I = 200pA Max
LOAD B
2.2MHz Bandwidth, 1.2V/µs SR
C-Load is a trademark of Linear Technology Corporation.
sn16789 16789fs
LT/TP 0104 1K • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
16
●
●
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
©LINEAR TECHNOLOGY CORPORATION 2003
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