VCA2611 Datasheet, PDF (1/19 Pages) Burr-Brown (TI) – Dual, Variable-Gain Amplifier with Low-Noise Preamp

VCA2616
VCA2616
VCA2611
SBOS234E – MARCH 2002 – REVISED NOVEMBER 2004
Dual, Variable-Gain Amplifier
with Low-Noise Preamp
FEATURES
q LOW-NOISE PREAMP:
– Low Input Noise: 0.95nV/√Hz
– Active Termination Noise Reduction
– Switchable Termination Value
– 80MHz Bandwidth
– 5dB to 25dB Gain
– Differential In and Out
q LOW-NOISE VARIABLE GAIN AMPLIFIER:
– Low-Noise VCA
– Up to 40dB Gain Range
– 40MHz Bandwidth
– Differential In and Out
q LOW CROSSTALK: 66dB at Max Gain, 5MHz
q HIGH-SPEED VARIABLE GAIN ADJUST
q SWITCHABLE EXTERNAL PROCESSING
APPLICATIONS
q ULTRASOUND SYSTEMS
q WIRELESS RECEIVERS
q TEST EQUIPMENT
FB_CNTL
LNP_OUTN VCA_INN VCA_CNTL
RF_{2 FBSW}
RF_{1 FB}
VCA2616
(1 of 2 Channels)
Analog
Control
Maximum Gain Select
MGS₁ MGS₂ MGS₃
Maximum Gain
Select
DESCRIPTION
The VCA2616 and VCA2611 are dual, Low-Noise Preamplifiers
(LNP), plus low-noise Variable Gain Amplifiers (VGA). The
VCA2611 is an upgraded version of the VCA2616. The only
difference between the VCA2616 and the VCA2611 is the input
structure to the LNP. The VCA2616 is limited to –0.3V negative-
going input spikes; the VCA2611 is limited to –2.0V negative-
going input spikes. This change allows the user to use slower
and less expensive input clamping diodes prior to the LNP input.
In some designs, input clamping may not be required.
The combination of Active Termination (AT) and Maximum
Gain Select (MGS) allow for the best noise performance. The
VCA2616 and VCA2611 also feature low crosstalk and out-
standing distortion performance.
The LNP has differential input and output capability and is
strappable for gains of 5dB, 17dB, 22dB, or 25dB. Low input
impedance is achieved by AT, resulting in as much as a 4.6dB
improvement in noise figure over conventional shunt termina-
tion. The termination value can also be switched to accommo-
date different sources. The output of the LNP is available for
external signal processing.
The variable gain is controlled by an analog voltage whose
gain varies from 0dB to the gain set by the MGS. The ability
to program the variable gain also allows the user to optimize
dynamic range. The VCA input can be switched from the LNP
to external circuits for different applications. The output can be
used in either a single-ended or differential mode to drive high-
performance Analog-to-Digital (A/D) converters, and is cleanly
limited for optimum overdrive recovery.
The combination of low noise, gain, and gain range program-
mability makes the VCA2616 and VCA2611 versatile building
blocks in a number of applications where noise performance
is critical. The VCA2616 and VCA2611 are available in a
TQFP-48 package.
Input
LNP_INP
LNP
Gain
Set
LNP_GS1
LNP_GS2
LNP_GS3
LNP_INN
Low Noise
Preamp
5dB to 25dB
Voltage
Controlled
Attenuator
Programmable
Gain Amplifier
24 to 45dB
VCA_OUTN
VCA_OUTP
LNP_OUTP VCA_INP SEL
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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