LTC6911-1 View Datasheet(PDF) - Linear Technology

Part Name

Description

Manufacturer

LTC6911-1

Dual Matched Amplifiers with Digitally Programmable Gain in MSOP

Linear Technology 

LTC6911-1/LTC6911-2

APPLICATIO S I FOR ATIO

Construction and Instrumentation Cautions

Electrically clean construction is important in applications

seeking the full dynamic range of the LTC6911 family of

dual amplifiers. It is absolutely critical to have AGND either

AC bypassed or wired directly, using the shortest possible

wiring, to a low impedance ground return for best channel-

to-channel isolation. Short, direct wiring will minimize

parasitic capacitance and inductance. High quality supply

bypass capacitors of 0.1µF near the chip provide good

decoupling from a clean, low inductance power source.

But several cm of wire (i.e., a few microhenrys of induc-

tance) from the power supplies, unless decoupled by

substantial capacitance (>10µF) near the chip, can create

a high-Q LC resonance in the hundreds of kHz in the chip’s

supplies or ground reference. This may impair circuit

performance at those frequencies. A compact, carefully

laid out printed circuit board with a good ground plane

makes a significant difference in minimizing distortion and

maximizing channel isolation. Finally, equipment to mea-

sure amplifier performance can itself add to distortion or

noise floors. Checking for these limits with wired shorts

from INA to OUTA and INB to OUTB in place of the chip is

a prudent routine procedure.

sn691112 691112fs

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