GS2984 Datasheet, PDF (1/20 Pages) Gennum Corporation – GS2984 Adaptive Cable Equalizer

GS2984 Adaptive Cable Equalizer
Key Features
• SMPTE 424M, SMPTE 292M and SMPTE 259M
compliant
• Automatic cable equalization
• Multi-standard operation from 143Mb/s to 2.97Gb/s
• Performance optimized for 270Mb/s, 1.485Gb/s and
2.97Gb/s. Typical equalized length of Belden 1694A
cable:
Š 140m at 2.97Gb/s
Š 200m at 1.485Gb/s
Š 400m at 270Mb/s
• Supports DVB-ASI at 270Mb/s
• Manual bypass (useful for low data rates with slow
rise/fall times)
• Programmable carrier detect with squelch threshold
adjustment
• Differential outputs support DC coupling to 3.3V and
2.5V CML logic
• 0/6 dB gain boost selection pin
• Standard EIA/JEDEC logic control and status signal
levels
• Single 3.3V power supply operation
• 195mW power consumption (typical)
• Wide temperature range of -40ºC to +85ºC
• Small footprint QFN package (4mm x 4mm)
Š Drop-in compatible with the GS2974
• Pb-free and RoHS compliant
Applications
• SMPTE 424M, SMPTE 292M and SMPTE 259M coaxial
cable serial digital interfaces
Description
The GS2984 is a high-speed BiCMOS integrated circuit
designed to equalize and restore signals received over 75Ω
coaxial cable.
The device is designed to support SMPTE 424M,
SMPTE292M and SMPTE 259M, and is optimized for
performance at 270Mb/s, 1.485Gb/s and 2.97Gb/s.
The GS2984 features DC restoration to compensate for the
DC content of SMPTE pathological test patterns.
The Carrier Detect output pin (CD) indicates whether a
valid input signal has been detected. It can be connected
directly to the MUTE pin to mute the output on loss of
carrier. A voltage programmable threshold, which can be
changed via the SQ_ADJ pin, forces CD high when the
input signal amplitude falls below the threshold. This
allows the GS2984 to distinguish between low-amplitude
SDI signals and noise at the input of the device.
The equalizing and DC restore stages are disengaged when
the BYPASS pin is HIGH. No equalization occurs in Bypass
mode.
The GS2984 includes a gain selection pin (GAIN_SEL)
which, when tied HIGH, compensates for 6dB flat
attenuation.
The differential outputs can be DC-coupled to Gennum
3.3V cable drivers and reclockers and to industry-standard
3.3V and 2.5V CML logic using the CMSET pin.
The GS2984 is footprint and drop-in compatible with
existing GS2974 designs, with no additional application
changes required.
The device is available in a 16-pin, 4mm x 4mm QFN
package.
Power consumption of the GS2984 is typically 195mW.
The GS2984 is Pb-free, and the encapsulation compound
does not contain halogenated flame retardant.
This component and all homogeneous subcomponents are
RoHS compliant.
GS2984 Adaptive Cable Equalizer
Data Sheet
50985 - 3
March 2010
www.gennum.com
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