11

®

OPA641

NOISE FIGURE

The OPA641 voltage and current noise spectral densities are

specified in the Typical Performance Curves. For RF appli-

cations, however, Noise Figure (NF) is often the preferred

noise specification since it allows system noise performance

to be more easily calculated. The OPA641’s Noise Figure vs

Source Resistance is shown in Figure 7.

ENVIRONMENTAL (Q) SCREENING

The inherent reliability of a semiconductor device is con-

trolled by the design, materials and fabrication of the device

—it cannot be improved by testing. However, the use of

environmental screening can eliminate the majority of those

units which would fail early in their lifetimes (infant mortal-

ity) through the application of carefully selected accelerated

stress levels. Burr-Brown “Q-Screening” provides environ-

mental screening to our standard industrial products, thus

enhancing reliability. The screening illustrated in the follow-

ing table is performed to selected stress levels similar to

those of MIL-STD-883.

FIGURE 7. Noise Figure vs Source Resistance.

SPICE MODELS

Computer simulation using SPICE is often useful when

analyzing the performance of analog circuits and systems.

This is particularly true for Video and RF amplifier circuits

where parasitic capacitance and inductance can have a major

effect on circuit performance. SPICE models are available

for the OPA641. Contact Burr-Brown Applications Depart-

ment to receive a spice diskette.

SCREEN

METHOD

Internal Visual

Burr-Brown QC4118

Stabilization Bake

Temperature = 150

°C, 24 hrs

Temperature Cycling

Temperature = –65

°C to 150°C, 10 cycles

Burn-In Test

Temperature = 125

°C, 160 hrs minimum

Centrifuge

20,000G

Hermetic Seal

Gross: per Fluorocarbon bubble test, 60PSiG

Electrical Tests

As described in specifications tables.

External Visual

Burr-Brown QC5150

NOTE: Q-Screening is available on the HSQ package only.

DEMONSTRATION BOARDS

Demonstration boards to speed prototyping are available.

Refer to the DEM-OPA64X Datasheet for details.

Source Resistance (

Ω)

10

100

1k

10k

25

20

15

10

5

0

100k

NF = 10 LOG 1 +

e

n

2

4KTR

S