VCA2612 Datasheet, PDF (1/19 Pages) Burr-Brown (TI) – TMDual, VARIABLE GAIN AMPLIFIER with Low Noise Preamp

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VCA2612
VCA2612
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TM _{Dual, VARIABLE GAIN AMPLIFIER}
with Low Noise Preamp
FEATURES
DESCRIPTION
q LOW NOISE PREAMP:
• Low Input Noise: 1.25nV/√Hz
• Active Termination Noise Reduction
• Switchable Termination Value
• 80MHz Bandwidth
• 5dB to 25dB Gain
• Differential Input /Output
q LOW NOISE VARIABLE GAIN AMPLIFIER:
• Low Noise VCA: 3.3nV/√Hz, Differential
Programming Optimizes Noise Figure
• 24dB to 45dB Gain
• 40MHz Bandwidth
• Differential Input /Output
q LOW CROSSTALK: 52dB at Max Gain, 5MHz
q HIGH-SPEED VARIABLE GAIN ADJUST
q SWITCHABLE EXTERNAL PROCESSING
APPLICATIONS
q ULTRASOUND SYSTEMS
q WIRELESS RECEIVERS
q TEST EQUIPMENT
The VCA2612 is a highly integrated, dual receive chan-
nel, signal processing subsystem. Each channel of the
product consists of a low noise pre-amplifier (LNP) and
a Variable Gain Amplifier (VGA). The LNP circuit
provides the necessary connections to implement Active
Termination (AT), a method of cable termination which
results in up to 4.6dB noise figure improvement. Differ-
ent cable termination characteristics can be accommo-
dated by utilizing the VCA2612’s switchable LNA feed-
back pins. The LNP has the ability to accept both
differential and single ended inputs, and generates a
differential output signal. The LNP provides strappable
gains of 5dB, 17dB, 22dB and 25dB.
The output of the LNP can be accessed externally for
further signal processing, or fed directly into the VGA.
The VCA2612’s VGA section consists of two parts, the
Voltage Controlled Attenuator (VCA) and the Program-
mable Gain Amplifier (PGA). The gain and gain range
of the Programmable Gain Amplifier can be digitally
programmed. The combination of these two program-
mable elements results in a variable gain ranging from
0dB up to a maximum gain as defined by the user
through external connections. The output of the VGA
can be used in either a single-ended or differential mode
to drive high performance analog-to-digital converters.
The VCA2612 also features low crosstalk and outstand-
ing distortion performance. The combination of low
noise, and gain range programmability make the
VCA2612 a versatile building block in a number of
applications where noise performance is critical. The
VCA2612 is available in a TQFP-48 package.
FB_CNTL
LNP_OUTN VCA_INN
RF_{2 FBSW}
RF_{1 FB}
VCA2612
(1 of 2 Channels)
VCA_CNTL
Analog
Control
Maximum Gain Select
MGS₁ MGS₂ MGS₃
Maximum Gain
Select
Input
LNP_INP
LNP_GS1
LNP LNP_GS2
Gain Set
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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© 2000 Burr-Brown Corporation
PDS-11541B
V^PC^rinA^ted2ⁱⁿ6^U1^.S.2^{A. March, 2000}