Linear Technology LT1793 Datasheet

FEATURES

LT1793

Low Noise,

Picoampere Bias Current,

JFET Input Op Amp

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DESCRIPTIO

■

Input Bias Current, Warmed Up: 10pA Max

■

100% Tested Low Voltage Noise: 8nV/√Hz Max

■

A Grade 100% Temperature Tested

■

Offset Voltage Over Temp: 1mV Max

■

Input Resistance: 1013Ω

■

Very Low Input Capacitance: 1.5pF

■

Voltage Gain: 1 Million Min

■

Gain-Bandwidth Product: 4.2MHz Typ

■

Guaranteed Specifications with ±5V Supplies

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APPLICATIO 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

, LTC and LT are registered trademarks of Linear Technology Corporation.

The LT®1793 achieves a new standard of excellence in
noise performance for a JFET op amp. For the first time low
voltage noise (6nV/√Hz) is simultaneously offered with
extremely low current noise (0.8fA/√Hz), providing the
lowest total noise for high impedance transducer applica­tions. Unlike most JFET op amps, the very low input bias
current (3pA typ) is maintained over the entire common
mode range which results in an extremely high input resis­tance (1013Ω). When combined with a very low input ca­pacitance (1.5pF) an extremely high input impedance
results, making the LT1793 the first choice for amplifying
low level signals from high impedance transducers. The
low input capacitance also assures high gain linearity when
buffering AC signals from high impedance transducers.

The LT1793 is unconditionally stable for gains of 1 or more,
even with 1000pF capacitive loads. Other key features are
250µV VOS and a voltage gain over 4 million. Each indi­vidual amplifier is 100% tested for voltage noise, slew rate
(3.4V/µs) and gain-bandwidth product (4.2MHz).

Specifications at ±5V supply operation are also provided.
For an even lower voltage noise please see the LT1792 data
sheet.

TYPICAL APPLICATIO

Low Noise Light Sensor with DC Servo

–

2

LT1793

+

3

D1

1N914

R5

R4

10k

1k

R2C2 > C1R1
C

–

V

D

V

OUT

330mV/µWATT FOR 633nm WAVE LENGTH

HAMAMATSU

S1336-5BK

[phone]

1N914

C

D

2N3904

D2

U

C1

2pF

+

V

7

6

4

–

V

R3
1k

= PARASITIC PHOTODIODE CAPACITANCE

= 100mV/µWATT FOR 200nm WAVE LENGTH

C2 0.022µF

+

V

LT1097

–

V

R1
1M

–

+

R2

100k

1793 TA01

1kHz Output Voltage Noise

Density vs Source Resistance

10k

–

1k

10

1

100 10k 100k 1M1k

R

SOURCE

V

N

VN = √(V

+

V

OUT

100

TOTAL 1kHz VOLTAGE NOISE DENSITY (nV/√Hz)

V

N

SOURCE
RESISTANCE
ONLY

SOURCE RESISTANCE (Ω)

OP AMP

10M

)2 + 4kTRS + 2qIBR

TA = 25°C

= ±15V

V

S

100M

2

S

1793 TA02

1G

1

LT1793

A

W

O

LUTEXI TIS

S

A

WUW

U

ARB

G

(Note 1)

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

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/

PACKAGE

VOS ADJ

–IN A
+IN A

–

V

T

JMAX

Consult factory for Military grade parts.

O

RDER I FOR ATIO

TOP VIEW

1
2

A

3
4

N8 PACKAGE
8-LEAD PDIP

= 150°C, θJA = 80°C/W

ORDER PART

NUMBER

NC

8

+

V

7

OUT

6

ADJ

V

5

OS

LT1793ACN8
LT1793CN8
LT1793AIN8
LT1793IN8

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

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ORDER PART

NUMBER

LT1793ACS8
LT1793CS8
LT1793AIS8
LT1793IS8

S8 PART MARKING

1793A
1793

VOS ADJ

–IN A
+IN A

TOP VIEW

1

2

A

3

–

V

4

S8 PACKAGE

8-LEAD PLASTIC SO

T

= 160°C, θJA = 190°C/W

JMAX

NC

8

V+

7

OUT

6

ADJ

V

5

OS

1793AI
1793I

T

LECTRICAL C CHARA TERIST

E

SYMBOL PARAMETER CONDITIONS (Note 2) MIN TYP MAX MIN TYP MAX UNITS

V

OS

I

OS

I

B

e

n

i

n

R

IN

C

IN

V

CM

CMRR Common Mode Rejection Ratio V
PSRR Power Supply Rejection Ratio VS = ±4.5V to ± 20V 85 98 83 95 dB

Input Offset Voltage 0.25 0.8 0.25 0.9 mV

V

S

Input Offset Current Warmed Up (Note 3) 1.5 7 2.5 15 pA

T

J

Input Bias Current Warmed Up (Note 3) 3 10 4.0 20 pA

T

J

Input Noise Voltage 0.1Hz to 10Hz 2.4 2.4 µV
Input Noise Voltage Density fO = 10Hz 11.5 11.5 nV/√Hz

f

O

Input Noise Current Density fO = 10Hz, fO = 1kHz (Note 4) 0.8 1 fA/√Hz
Input Resistance

Differential Mode 10
Common Mode V

Input Capacitance 1.5 1.5 pF

Input Voltage Range (Note 5) 13.0 13.5 13.0 13.5 V

CM

V

S

CM

ICS

= ±5V 0.45 1.4 0.45 1.6 mV

= 25°C (Note 6) 0.5 2 0.7 4 pA

= 25°C (Note 6) 1 3 1.5 5 pA

= 1000Hz 6 8 6 8 nV/√Hz

= –10V to 13V 10

= ±5V 2.0 2.0 pF

= –10V to 13V 83 102 81 96 dB

= 25°C, VS = ±15V, V

A

= 0V, unless otherwise noted.

CM

LT1793AC/LT1793AI

14
13

–10.5 –11.0 – 10.5 – 11.0 V

LT1793C/LT1793I

14

10

13

10

P-P

Ω
Ω

2

LT1793

T

LECTRICAL C CHARA TERIST

E

SYMBOL PARAMETER CONDITIONS (Note 2) MIN TYP MAX MIN TYP MAX UNITS

A

VOL

V

OUT

SR Slew Rate RL ≥ 2k (Note 7) 2.3 3.4 2.3 3.4 V/µs
GBW Gain-Bandwidth Product fO = 100kHz 2.5 4.2 2.5 4.2 MHz
I

S

Large-Signal Voltage Gain VO = ±12V, RL = 10k 1000 4500 900 4400 V/mV

V

O

Output Voltage Swing RL = 10k ±13.0 ±13.2 ±13.0 ±13.2 V

R

L

Supply Current 4.2 5.20 4.2 5.20 mA

V

S

Offset Voltage R
Adjustment Range

POT

ICS

= ±10V, RL = 1k 500 3500 400 3000 V/mV

= 1k ±12.0 ±12.3 ±12.0 ±12.3 V

= ±5V 4.2 5.15 4.2 5.15 mA

(to VEE) = 10k 13 13 mV

= 25°C, VS = ±15V, V

A

The ● denotes specifications which apply over the temperature range 0°C ≤ TA ≤ 70°C, otherwise specifications are at TA = 25°C.

V

= ±15V, V

S

SYMBOL PARAMETER CONDITIONS (Note 2) MIN TYP MAX MIN TYP MAX UNITS

V

OS

∆V

OS

∆Temp Voltage Drift
I

OS

I

B

V

CM

CMRR Common Mode Rejection Ratio V
PSRR Power Supply Rejection Ratio VS = ±4.5V to ± 20V ● 83 97 81 94 dB
A

VOL

V

OUT

SR Slew Rate RL ≥ 2k (Note 7) ● 2.2 3.3 2.2 3.3 V/µs
GBW Gain-Bandwidth Product fO = 100kHz ● 2.2 3.3 2.2 3.3 MHz
I

S

= 0V, unless otherwise noted. (Note 9)

CM

Input Offset Voltage ● 0.50 1.0 1.0 3.5 mV

= ±5V ● 0.75 1.6 1.6 4.2 mV

V

S

Average Input Offset (Note 6) ● 513 850 µV/°C

Input Offset Current ● 15 100 20 130 pA
Input Bias Current ● 130 400 150 500 pA
Input Voltage Range (Note 5) ● 12.9 13.4 12.9 13.4 V

● – 10.0 –10.8 – 10.0 – 10.8 V

= –10V to 12.9V ● 79 100 77 95 dB

CM

Large-Signal Voltage Gain VO = ±12V, RL = 10k ● 900 3600 800 3400 V/mV

= ±10V, RL = 1k ● 500 2600 400 2400 V/mV

V

O

Output Voltage Swing RL = 10k ● ±12.9 ±13.2 ±12.9 ±13.2 V

R

= 1k ● ±11.9 ±12.15 ±11.9 ±12.15 V

L

Supply Current ● 4.2 5.30 4.2 5.30 mA

V

= ±5V ● 4.2 5.25 4.2 5.25 mA

S

= 0V, unless otherwise noted.

CM

LT1793AC/LT1793AI

LT1793AC LT1793C

LT1793C/LT1793I

3

LT1793

LECTRICAL C CHARA TERIST

E

–40°C ≤ TA ≤ 85°C. VS = ±15V, V

SYMBOL PARAMETER CONDITIONS (Note 2) MIN TYP MAX MIN TYP MAX UNITS

V

OS

∆V
∆Temp Voltage Drift

I

OS

I

B

V

CM

CMRR Common Mode Rejection Ratio V
PSRR Power Supply Rejection Ratio VS = ±4.5V to ± 20V ● 81 96 79 93 dB
A

VOL

V

OUT

SR Slew Rate RL ≥ 2k ● 2.1 3.2 2.1 3.2 V/µs
GBW Gain-Bandwidth Product fO = 100kHz ● 23.1 23.1 MHz
I

S

OS

Input Offset Voltage ● 0.65 1.3 1.6 4.8 mV

Average Input Offset (Note 6) ● 513 950 µV/°C

Input Offset Current ● 80 300 100 400 pA
Input Bias Current ● 700 2400 800 3000 pA
Input Voltage Range (Note 5) ● 12.6 13.0 12.6 13.0 V

Large-Signal Voltage Gain VO = ±12V, RL = 10k ● 850 3300 750 3000 V/mV

Output Voltage Swing RL = 10k ● ±12.8 ±13.1 ±12.8 ±13.1 V

Supply Current ● 4.2 5.40 4.2 5.40 mA

= 0V, unless otherwise noted. (Notes 8, 9)

CM

V

S

CM

V

O

R

L

V

S

ICS

= ±5V ● 1.00 1.9 2.0 5.5 mV

= –10V to 12.6V ● 78 99 76 94 dB

= ±10V, RL = 1k ● 400 2200 300 2000 V/mV

= 1k ● ±11.8 ±12.1 ±11.8 ±12.1 V

= ±5V ● 4.2 5.35 4.2 5.35 mA

The ● denotes specifications which apply over the temperature range

LT1793AC/LT1793AI LT1793C/LT1793I

● – 10.0 –10.5 – 10.0 – 10.5 V

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: I
from 25°C measurements and 32°C characterization data.

Note 4: Current noise is calculated from the formula:

where q = 1.6 • 10
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).

and IOS readings are extrapolated to a warmed-up temperature

B

1/2

= (2qIB)

i

n

–19

coulomb. The noise of source resistors up to 200M

Note 6: This parameter is not 100% tested.
Note 7: Slew rate is measured in A

measured at ±2.5V.
Note 8: The LT1793AC and LT1793C 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 LT1793I is guaranteed to meet the extended
temperature limits. The LT1793AC and LT1793AI grade are 100%
temperature tested for the specified temperature range.

Note 9: The LT1793 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.

= –1; input signal is ±7.5V, output

V

4