GS2994 Adaptive Cable Equalizer
1 of 3GS2994 Adaptive Cable Equalizer
Product Brief
53071 - B June 2010
www.gennum.com
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:
140m at 2.97Gb/s
200m at 1.485Gb/s
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
• Automatic power-down on loss of signal
Standby power <30mW (typical)
• Differential outputs support DC-coupling to 1.2V, 2.5V
and 3.3V CML logic
• 0/6 dB gain boost selection pin
• Selectable de-emphasis: 2dB, 4dB and 6dB
• Standard EIA/JEDEC logic control and status signal
levels
• Single 3.3V power supply operation
• 167mW power consumption (typical)
• Wide operating temperature range of -40ºC to +85ºC
• Small footprint QFN package (4mm x 4mm)
Footprint compatible with the GS2974 and the
GS2984
• Pb-free and RoHS compliant
Applications
• SMPTE 424M, SMPTE 292M and SMPTE 259M coaxial
cable serial digital interfaces
Description
The GS2994 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 GS2994 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 SLEEP pin to enable automatic power-down
upon loss of carrier. In the manual sleep mode, 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 GS2994
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 GS2994 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
1.2V, 2.5V and 3.3V CML logic using the VCC_O pin. In
general, DC-coupling to any termination voltage between
1.2V and 3.3V is supported.
The GS2994 also includes programmable de-emphasis with
three operating levels in order to support long PCB traces.
The GS2994 is footprint and drop-in compatible with
existing GS2974 and GS2984 designs.
The device is available in a 16-pin, 4mm x 4mm QFN
package.
Power consumption of the GS2994 is typically 167mW
when DC-coupled at 1.2V.
The GS2994 is Pb-free, and the encapsulation compound
does not contain halogenated flame retardant.
This component and all homogeneous subcomponents are
RoHS compliant.
