
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
Fine: He leak rate < 5 x 1
x
0
–8
atm cc/s, 30PSiG
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.
N
Source Resistance (
)
10
100
1k
10k
25
20
15
10
5
0
100k
NF = 10 LOG 1 +
e
n2
+ (I
n
R
S
)
2
4KTR
S