LT1792
Low Noise, Precision,
JFET Input Op Amp
FEATURES
s
s
s
s
s
s
DESCRIPTIO
100% Tested Low Voltage Noise: 6nV/√Hz Max
A Grade 100% Temperature Tested
Voltage Gain: 1.2 Million Min
Offset Voltage Over Temp: 800µV Max
Gain-Bandwidth Product: 5.6MHz Typ
Guaranteed Specifications with
±5V
Supplies
The LT
®
1792 achieves a new standard of excellence in
noise performance for a JFET op amp. The 4.2nV/√Hz
voltage noise combined with low current noise and
picoampere bias currents make the LT1792 an ideal choice
for amplifying low level signals from high impedance
capacitive transducers.
The LT1792 is unconditionally stable for gains of 1 or more,
even with load capacitances up to 1000pF. Other key
features are 600µV V
OS
and a voltage gain of over 4 million.
Each individual amplifier is 100% tested for voltage noise,
slew rate and gain bandwidth.
The design of the LT1792 has been optimized to achieve
true precision performance with an industry standard
pinout in the SO-8 package. Specifications are also pro-
vided for
±5V
supplies.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
s
s
s
s
s
s
Photocurrent Amplifiers
Hydrophone Amplifiers
High Sensitivity Piezoelectric Accelerometers
Low Voltage and Current Noise Instrumentation
Amplifier Front Ends
Two and Three Op Amp Instrumentation Amplifiers
Active Filters
TYPICAL APPLICATIO
Low Noise Hydrophone Amplifier with DC Servo
5V TO 15V
1kHz Input Noise Voltage Distribution
V
S
=
±15V
T
A
= 25°C
270 OP AMPS TESTED
LT1792
R2 C1*
200Ω
6
C2
0.47µF
R4
1M
R5
1M
OUTPUT
PERCENT OF UNITS (%)
–5V TO –15V
C
T
HYDRO-
PHONE
R6
100k
6
LT1097
3
R7
1M
DC OUTPUT
≤
2.5mV FOR T
A
< 70°C
OUTPUT VOLTAGE NOISE = 128nV/√Hz AT 1kHz (GAIN = 20)
C1
≈
C
T
≈
100pF TO 5000pF; R4C2 > R8C
T
; *OPTIONAL
–
R8
100M
+
+
3
–
R1*
100M
R3
3.9k
40
2
7
30
4
20
2
10
0
3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6
INPUT VOLTAGE NOISE (nV/√Hz)
1792 TA02
1792 TA01
U
U
U
1
LT1792
ABSOLUTE
AXI U
RATI GS
Supply Voltage .....................................................
±20V
Differential Input Voltage ......................................
±40V
Input Voltage (Equal to Supply Voltage) ...............
±20V
Output Short-Circuit Duration ........................ Indefinite
Operating Temperature Range ............... – 40°C to 85°C
PACKAGE/ORDER I FOR ATIO
TOP VIEW
V
OS
ADJ 1
–IN A 2
+IN A 3
V
–
4
N8 PACKAGE
8-LEAD PDIP
T
JMAX
= 140°C,
θ
JA
= 130°C/W
A
ORDER PART
NUMBER
8 NC
7 V
+
6 OUT
5 V
OS
ADJ
LT1792ACN8
LT1792CN8
LT1792AIN8
LT1792IN8
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
SYMBOL
V
OS
I
OS
I
B
e
n
PARAMETER
Input Offset Voltage
V
S
=
±
5V
Input Offset Current
Input Bias Current
Input Noise Voltage
Input Noise Voltage Density
i
n
R
IN
Input Noise Current Density
Input Resistance
Differential Mode
Common Mode
Input Capacitance
V
S
=
±5V
Input Voltage Range (Note 5)
Common Mode Rejection Ratio
Power Supply Rejection Ratio
T
A
= 25°C, V
S
=
±15V,
V
CM
= 0V, unless otherwise noted. (Note 9)
LT1792AC/LT1792AI
MIN
TYP
MAX
0.2
0.4
100
300
2.4
8.3
4.2
10
10
11
10
11
10
10
14
27
13.0
–10.5
13.5
–11.0
105
105
13.0
–10.5
82
83
6.0
0.6
1.0
400
800
LT1792C/LT1792I
MIN
TYP
MAX
0.2
0.4
100
300
2.4
8.3
4.2
10
10
11
10
11
10
10
14
27
13.5
–11.0
100
98
6.0
0.8
1.3
400
800
UNITS
mV
mV
pA
pA
µV
P-P
nV/√Hz
nV/√Hz
fA/√Hz
Ω
Ω
Ω
pF
pF
V
V
dB
dB
CONDITIONS (Note 2)
Warmed Up (Note 3)
Warmed Up (Note 3)
0.1Hz to 10Hz
f
O
= 10Hz
f
O
= 1000Hz
f
O
= 10Hz, f
O
= 1000Hz (Note 4)
V
CM
= –10V to 8V
V
CM
= 8V to 11V
C
IN
V
CM
CMRR
PSRR
V
CM
= –10V to 13V
V
S
=
±4.5V
to
±20V
2
U
U
W
W W
U
W
(Note 1)
Specified Temperature Range
Commercial (Note 8) ......................... – 40°C to 85°C
Industrial ........................................... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec) ................ 300°C
TOP VIEW
V
OS
ADJ 1
–IN A 2
+IN A 3
V
–
4
A
ORDER PART
NUMBER
8 NC
7 V+
6 OUT
5 V
OS
ADJ
LT1792ACS8
LT1792CS8
LT1792AIS8
LT1792IS8
S8 PART MARKING
1792A
1792
1792AI
1792I
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 160°C,
θ
JA
= 190°C/W
85
88
LT1792
ELECTRICAL CHARACTERISTICS
SYMBOL
A
VOL
V
OUT
SR
GBW
I
S
PARAMETER
Large-Signal Voltage Gain
Output Voltage Swing
Slew Rate
Gain-Bandwidth Product
Supply Current
V
S
=
±5V
Offset Voltage
Adjustment Range
CONDITIONS
T
A
= 25°C, V
S
=
±15V,
V
CM
= 0V, unless otherwise noted.
LT1792AC/LT1792AI
MIN
TYP
MAX
1200
600
±13.0
±12.0
2.3
4.0
4800
4000
±13.2
±12.3
3.4
5.6
4.2
4.2
10
5.20
5.15
LT1792C/LT1792I
MIN
TYP
MAX
1000
500
±13.0
±12.0
2.3
4.0
4500
3000
±13.2
±12.3
3.4
5.6
4.2
4.2
10
5.20
5.15
UNITS
V/mV
V/mV
V
V
V/µs
MHz
mA
mA
mV
V
O
=
±12V,
R
L
= 10k
V
O
=
±10V,
R
L
= 1k
R
L
= 10k
R
L
= 1k
R
L
≥
2k (Note 7)
f
O
= 100kHz
R
POT
(to V
EE
) = 10k
The
q
denotes specifications which apply over the temperature range 0°C
≤
T
A
≤
70°C. V
S
=
±15V,
V
CM
= 0V,
unless otherwise noted. (Note 9)
SYMBOL
V
OS
∆V
OS
∆Temp
I
OS
I
B
V
CM
CMRR
PSRR
A
VOL
V
OUT
SR
GBW
I
S
PARAMETER
Input Offset Voltage
Average Input Offset
Voltage Drift
Input Offset Current
Input Bias Current
Input Voltage Range
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Large-Signal Voltage Gain
Output Voltage Swing
Slew Rate
Gain-Bandwidth Product
Supply Current
V
S
=
±5V
V
CM
= –10V to 12.9V
V
S
=
±4.5V
to
±20V
V
O
=
±12V,
R
L
= 10k
V
O
=
±10V,
R
L
= 1k
R
L
= 10k
R
L
= 1k
R
L
≥
2k (Note 7)
f
O
= 100kHz
CONDITIONS (Note 2)
V
S
=
±
5V
(Note 6)
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
LT1792AC
MIN
TYP
MAX
0.4
0.6
4
180
500
12.9
–10.0
81
85
900
500
13.4
–10.8
104
99
3600
2600
0.8
1.2
10
500
1800
LT1792C
MIN
TYP
MAX
0.8
1.2
7
180
500
12.9
–10.0
79
81
800
400
13.4
–10.8
99
97
3400
2400
2.7
3.2
40
500
1800
UNITS
mV
mV
µV/°C
pA
pA
V
V
dB
dB
V/mV
V/mV
V
V
V/µs
MHz
±12.9 ±13.2
±11.9 ±12.15
2.1
3.2
3.1
4.5
4.2
4.2
5.30
5.25
±12.9 ±13.2
±11.9 ±12.15
2.1
3.2
3.1
4.5
4.2
4.2
5.30
5.25
mA
mA
3
LT1792
ELECTRICAL CHARACTERISTICS
SYMBOL
V
OS
∆V
OS
∆Temp
I
OS
I
B
V
CM
CMRR
PSRR
A
VOL
V
OUT
SR
GBW
I
S
PARAMETER
Input Offset Voltage
Average Input Offset
Voltage Drift
Input Offset Current
Input Bias Current
Input Voltage Range
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Large-Signal Voltage Gain
Output Voltage Swing
Slew Rate
Gain-Bandwidth Product
Supply Current
V
S
=
±5V
The
q
denotes specifications which apply over the temperature range
– 40°C
≤
T
A
≤
85°C. V
S
=
±
15V, V
CM
= 0V, unless otherwise noted. (Notes 8, 9)
LT1792AC/LT1792AI
MIN
TYP
MAX
q
q
q
q
q
q
q
CONDITIONS (Note 2)
V
S
=
±5V
(Note 6)
LT1792C/LT1792I
MIN
TYP
MAX
1.2
1.5
7
300
1200
12.6
–10.0
78
79
750
300
±12.8
±11.8
2.0
2.9
13.0
–10.5
98
96
3000
2000
±13.1
±12.1
3.0
4.3
4.2
4.2
5.40
5.35
3.7
4.2
40
800
4000
UNITS
mV
mV
µV/°C
pA
pA
V
V
dB
dB
V/mV
V/mV
V
V
V/µs
MHz
mA
mA
0.5
0.8
4
300
1200
12.6
–10.0
80
83
850
400
±12.8
±11.8
2.0
2.9
13.0
–10.5
103
98
3300
2200
±13.1
±12.1
3.0
4.3
4.2
4.2
1.0
1.4
10
800
4000
V
CM
= –10V to 12.6V
V
S
=
±4.5V
to
±
20V
V
O
=
±12V,
R
L
= 10k
V
O
=
±10V,
R
L
= 1k
R
L
= 10k
R
L
= 1k
R
L
≥
2k
f
O
= 100kHz
q
q
q
q
q
q
q
q
q
q
5.40
5.35
Note 1:
Absolute Maximum Ratings are those values beyond which the
life of a device may be impaired.
Note 2:
Typical parameters are defined as the 60% yield of parameter
distributions of individual amplifiers.
Note 3:
Warmed-up I
B
and I
OS
readings are extrapolated to a chip
temperature of 32°C from 25°C measurements and 32°C characterization
data.
Note 4:
Current noise is calculated from the formula:
i
n
= (2qI
B
)
1/2
where q = 1.6 • 10
–19
coulomb. The noise of source resistors up to 200M
swamps the contribution of current noise.
Note 5:
Input voltage range functionality is assured by testing offset
voltage at the input voltage range limits to a maximum of 2.3mV
(A grade), to 2.8mV (C grade).
Note 6:
This parameter is not 100% tested.
Note 7:
Slew rate is measured in A
V
= – 1; input signal is
±7.5V,
output
measured at
±2.5V.
Note 8:
The LT1792AC and LT1792C are guaranteed to meet specified
performance from 0°C to 70°C and are designed, characterized and
expected to meet these extended temperature limits, but are not tested at
– 40°C and 85°C. The LT1792I is guaranteed to meet the extended
temperature limits. The LT1792AC and LT1792AI grade are 100%
temperature tested for the specified temperature range.
Note 9:
The LT1792 is measured in an automated tester in less than one
second after application of power. Depending on the package used,
power dissipation, heat sinking, and air flow conditions, the fully
warmed-up chip temperature can be 10°C to 50°C higher than the
ambient temperature.
4
LT1792
TYPICAL PERFOR A CE CHARACTERISTICS
0.1Hz to 10Hz Voltage Noise
100
RMS VOLTAGE NOISE DENSITY (nV/√Hz)
VOLTAGE NOISE (AT 1kHz) (nV/√Hz)
VOLTAGE NOISE (1µV/DIV)
0
2
6
4
TIME (SEC)
Input Bias and Offset Current
Over the Common Mode Range
400
INPUT BIAS AND OFFSET CURRENTS (pA)
INPUT BIAS AND OFFSET CURRENT (nA)
COMMON MODE LIMIT
REFERRED TO POWER SUPPLY (V)
T
A
= 25°C
V
S
=
±15V
NOT WARMED UP
300
200
BIAS CURRENT
100
OFFSET CURRENT
0
–15
10
–10
–5
0
5
COMMON-MODE RANGE (V)
15
1792 G22
Common Mode Rejection Ratio
vs Frequency
120
COMMON MODE REJECTION RATIO (dB)
POWER SUPPLY REJECTION RATIO (dB)
100
80
60
40
20
0
1k
10k
80
+PSRR
60
–PSRR
40
20
0
VOLTAGE GAIN (dB)
100k
1M
FREQUENCY (Hz)
U W
8
10
1792 G01
Voltage Noise vs Frequency
V
S
=
±15V
T
A
= 25°C
10
9
8
7
6
5
4
3
2
1
Voltage Noise
vs Chip Temperature
V
S
=
±15V
10
1/f CORNER
30Hz
1
1
10
100
1k
FREQUENCY (Hz)
10k
1792 G02
0
–75 –50 –25 0 25 50 75
TEMPERATURE (°C)
100 125
1792 G03
Input Bias and Offset Current
vs Chip Temperature
100
30
10
3
1
I
B
0.3
I
OS
0.1
0.03
0.01
– 75 – 50 – 25 0
25 50 75
TEMPERATURE (°C)
100 125
1792 G04
Common Mode Limit
vs Temperature
V
+
0
– 0.5
–1.0
–1.5
– 2.0
V
+
= 5V TO 20V
V
S
=
±15V
4.0
3.5
3.0
2.5
V
–
= – 5V TO – 20V
V
–
+ 2.0
– 60
–20
60
100
20
TEMPERATURE (°C)
140
1792 G05
Power Supply Rejection Ratio
vs Frequency
120
T
A
= 25°C
100
180
160
140
120
100
80
60
40
20
0
Voltage Gain vs Frequency
T
A
= 25°C
V
S
=
±
15V
10M
1792 G06
10
100
1k
10k 100k
FREQUENCY (Hz)
1M
10M
1792 G07
– 20
0.01
1
10k
100
FREQUENCY (Hz)
1M
100M
1792 G08
5
51单片机
