Amplifier Process and Trimming Technology
JFET Input Amplifiers
Process Technology
Bipolar
JFET input amplifiers have the advantage over bipolar devices by having
an extremely high input impedance along with low noise performance,
making them very useful in amplifier circuits using very small signals
such as high source impedance sensors and photodiodes. A typical JFET
has a voltage noise slightly larger than a BJT, but its current noise is
significantly lower.
Bipolar technology delivers the best overall performance amplifiers. It
offers high output current drive, high voltage operation, and low noise.
Extremely Fast Complementary Bipolar (XFCB 1.5)
Analog Device’s XFCB 1.5 technology is a suite of advanced bipolar
fabrication processes that features dielectric isolation, high speed
complementary NPNs and PNPs with 3 GHz to 8 GHz frequency transition,
precision capacitors, and low temperature-coefficient thin film resistors
that can be trimmed at the wafer level. Dielectric isolation allows much
tighter spacing between components and removes the possibility of latch-
up. Nonlinear device-to-substrate capacitance that limits device speed and
distortion performance is eliminated. XFCB1.5 has supply voltage options
from 8 V to 26 V; this allows the selection of the fastest devices possible
for the required input and output voltage ranges.
Trimming Technology
Laser Trim
When extremely fine adjustment is required, laser trimming is most
effective. By controlling the path and speed of the laser beam, the
resistor’s value can be adjusted to very precise values. Analog Devices
pioneered the use of thin film resistors and laser trimming and uses
this technology extensively in precision amplifiers, references,
and converters.
XFCB3
Zener Zapping
Analog Devices’ XFCB3 technology features full dielectric isolation, silicon-
germanium hetero-junction NPNs with frequency transition up to 50 GHz
and double-poly PNPs with frequency transition up to 18 GHz, precision
capacitors, and low temperature coefficient thin film resistors. Minimum
feature size is a factor of three less than XFCB1.5. This process family has
enabled a new generation of high speed, ultralow distortion differential
amplifiers and op amps.
With each zap removing a predefined resistance value, the nature of
the trims is discrete. It is most cost-effective for fairly large geometry
processes. Analog Devices pioneered the use of Zener-zap trimming and
created the industry standard OP07 precision amplifier.
DigiTrim
Analog Devices’ DigiTrim™ is a patented in-package trimming process that
delivers guaranteed high accuracy. This in-package process technology
eliminates the need for laser trimming during manufacturing and
minimizes the input offset of operational amplifiers.
36 V iPolar
Analog Devices’ iPolar™ 36 V precision bipolar process is highly optimized
for linear circuits, yielding new levels of performance, size, and value. The
iPolar process combines the advantages of precision bipolar and JFET
with lateral dielectric isolation and modular processing. The transistors
on iPolar devices have been redesigned from the ground up and are
optimized for speed, noise, matching, linearity, and stability at lower power
levels. This enables greater signal chain integration without compromising
performance.
16 V iCMOS Amplifiers
Analog Devices’ iCMOS® industrial manufacturing process technology
combines submicron CMOS with high voltage complementary bipolar
technologies. It enables the development of a wide range of high
performance analog ICs capable of 30 V operation in a smaller footprint.
Unlike analog ICs using conventional CMOS processes, iCMOS components
can tolerate high supply voltages, while providing increased performance,
dramatically lower power consumption, and reduced package size. iCMOS
components tolerate high voltages (greater than 6 V regular CMOS amps)
while employing digital design techniques such as auto-zero and DigiTrim
technologies.
Operational Amplifier Selection Guide
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ADI [ ADI ]
