IFPA300, IFPA301

Monolithic JFET Preamplifier

Description & Features

The IFPA300 series is an inverting transimpedance

amplifier featuring extremely low noise and a wide

gain-bandwidth suitable as a charge-sensitive pre-

amplifier for a broad range of applications.

The monolithic IFPA300 series contain 8 n-channel

epitaxial-channel diffused-gate JFETs to achieve

optimally low 1/f noise performance over a wide

temperature range (120K-300K).

DC open loop gain

85 dB

GBW

200 MHz

3.0 nV/

√Hz

General Specifications

Power Dissipation at VDD = 12 V

<100 mW

Input Leakage Current (T = 300 K)

10 pA

Input-Referred Noise Voltage (f = 10 kHz)

0.6 nV/

√Hz

Input-Referred Noise Voltage (f = 10 Hz)

3.0 nV/

√Hz

Output Range at VDD = 12 V

4.0 V (5.0 V Max)

Designed to drive 50

Ω load.

Charge Sensitive

Preamplifier Specifications

The IFPA300 Series is actually tailored to detector

capacitance in the 100 Ð 1000 pF range.

Input Open-Loop Capacitance

60 pF

Rise Time (CD = 500 pF, Cf = 33 pF)

20 ns

Equivalent Noise Charge

(Measured with semigaussian shaping, peaking

Absolute maximum ratings at TA = 25°C

All pins (except Input) referenced to Bias 3

85 dB

Input to Bias 3

Ø V

Power Dissipation

225 mW

Derating Factor

1.8 mW/°C

Operating Temperature

150°C

At this time, there are two units in this family.

The 300/301 Series gives more flexibility with respect

to output transistor drain.

The 310/311 Series ties the output transistor drain to

Simplified Schematic Circuit

Packages & Test Circuit Overside

x

01/99

1000 N. Shiloh Road, Garland, TX 75042

www.interfet.com

J5

J6

J7

J1

J2

J3

J4

J8

VSS

VDD

Open

Substrate

Source

Output

Open

Drain

Output

Bias 1

Bias 2

Bias 3

Input

Databook.fxp

1/13/99 2:09 PM

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