VCA8617_14 Datasheet, PDF (1/35 Pages) Texas Instruments – 8-Channel VARIABLE GAIN AMPLIFIER

VCA8617
www.ti.com
SBOS308F – AUGUST 2004 – REVISED NOVEMBER 2009
8-Channel VARIABLE GAIN AMPLIFIER
Check for Samples: VCA8617
FEATURES
1
•23 3V OPERATION
• LOW INPUT NOISE:
– 1.05nV/√Hz at f_IN = 5MHz
• EXTREMELY LOW POWER OPERATION:
– 103mW/CHANNEL
• INTEGRATED LOW-PASS, ANTI-ALIASING
BUTTERWORTH FILTER
– 14.5MHz BANDWIDTH
• INTEGRATED INPUT CLAMP DIODES
• DIFFERENTIAL OUTPUT
• INTEGRATED INPUT LNA
• READABLE CONTROL REGISTERS
• INTEGRATED CONTINUOUS WAVE (CW)
PROCESSOR
DESCRIPTION
The VCA8617 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 20dB gain 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 vary between
four discrete settings of 25dB, 30dB, 35dB, and
40dB. 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 low-pass filter.
VCA8617
D_OUT
D_IN
CLK
CS
5x8
FIFO
Serial PG
Interface _ATN
IN1
LNA
·
·
V_LNA
·
IN8
LNA
CW Processor
CW(0-9)
(8 x 10)
10
Analog
Control
VCA
VCA
PGA
PGA
2-Pole
Filter
·
·
·
2-Pole
Filter
V_CNTRL
OUT1
OUT1
OUT8
OUT8
V_LNA
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Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SPI is a trademark of Motorola, Inc.
2
All other trademarks are the property of their respective owners.
3
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2004–2009, Texas Instruments Incorporated