1

LT1793

Low Noise,

Picoampere Bias Current,

JFET Input Op Amp

1kHz Output Voltage Noise

Density vs Source Resistance

SOURCE RESISTANCE (

Ω)

10k

1k

100

10

1

100

10k

100k

1M

1k

10M

1793 TA02

100M 1G

–

+

SOURCE

RESISTANCE

ONLY

The LT

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 applica-

tions. 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 resis-

Ω). When combined with a very low input ca-

pacitance (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

250

vidual 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.

s

Input Bias Current, Warmed Up: 10pA Max

s

100% Tested Low Voltage Noise: 8nV/

√Hz Max

s

A Grade 100% Temperature Tested

s

Offset Voltage Over Temp: 1mV Max

s

Ω

s

Very Low Input Capacitance: 1.5pF

s

Voltage Gain: 1 Million Min

s

Gain-Bandwidth Product: 4.2MHz Typ

s

Guaranteed Specifications with

±5V Supplies

s

Photocurrent Amplifiers

s

Hydrophone Amplifiers

s

High Sensitivity Piezoelectric Accelerometers

s

Low Voltage and Current Noise Instrumentation

Amplifier Front Ends

s

Two and Three Op Amp Instrumentation Amplifiers

s

Active Filters

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

1793 TA01

R1

1M

C1

2pF

LT1097

R2C2 > C1R1

330mV/

µWATT FOR 633nm WAVE LENGTH

R5

10k

D2

1N914

R4

1k

D1

1N914

R3

1k

6

7

4

3

2

LT1793

C2 0.022

µF

HAMAMATSU

S1336-5BK

(908) 231-0960

R2

100k

2N3904

Low Noise Light Sensor with DC Servo

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO