VCA8613 Datasheet, PDF (1/21 Pages) Texas Instruments – 8-Channel VARIABLE GAIN AMPLIFIER

VCA8613 ®
VCA8613
SBOS200C – APRIL 2003 – REVISED MARCH 2004
8-Channel
VARIABLE GAIN AMPLIFIER
FEATURES
q 3V OPERATION
q LOW INPUT NOISE: 1.2nV√Hz at f_IN = 5MHz
q EXTREMELY LOW POWER OPERATION:
75mW/CHANNEL
q INTEGRATED LOW-PASS, 2-POLE FILTER
14MHz BANDWIDTH
q INTEGRATED INPUT CLAMP DIODES
q DIFFERENTIAL OUTPUT
q INTEGRATED INPUT LNA
q READABLE CONTROL REGISTERS
q INTEGRATED CONTINUOUS WAVE (CW)
PROCESSOR
DESCRIPTION
The VCA8613 is an 8-channel variable gain amplifier ideally
suited to portable ultrasound applications. Excellent dynamic
performance enables use in low-power, high-performance
portable applications. Each channel consists of a Low-Noise
pre-Amplifier (LNA) and a Variable Gain Amplifier (VGA). The
differential outputs of the LNA can be switched through the
8x10 cross-point switch, which is programmable through the
serial interface input port.
The output of the LNA is fed directly into the VGA stage. The
VGA consists of two parts, a Voltage Controlled Attenuator
(VCA) and a Programmable Gain Amplifier (PGA). The gain and
gain range of the PGA can be digitally configured separately. The
gain of the PGA can be varied between two discrete settings of
21dB and 26dB. The VCA has four programmable maximum
attenuation settings: 29dB, 33dB, 36.5dB, and 40dB. Also, the
VCA can be continuously varied by a control voltage from 0dB to
a maximum of 29dB, 33dB, 36.5dB, and 40dB.
The output of the PGA feeds directly into an integrated
2-pole, low-pass filter, allowing for direct connection to a
differential input Analog-to-Digital Converter (ADC), such as
the ADS5121 or ADS5122 from Texas Instruments. The
VCA8613 is available in a TQFP-64 package.
DATA
CLK
CS
D^(0-3)
Serial
Interface
5x8
FIFO
LNAIN1
LNAIN8
LNA
V_LNA
•
•
•
LNA
CW Processor
CW^(1-10)
Analog
Control
Attenuator
Attenuator
PGA
PGA
2-Pole
Filter
•
•
•
2-Pole
Filter
OutP⁽¹⁾
OutN⁽¹⁾
OutP⁽⁸⁾
OutN⁽⁸⁾
V_LNA
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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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