GS1674 Datasheet, PDF (1/16 Pages) Semtech Corporation – Adaptive Cable Equalizer

GS1674
GS1674 Adaptive Cable Equalizer
The GS1674 is a high-speed BiCMOS integrated circuit designed to equalize and restore signals received over 75Ω coaxial
cable. The device is optimized for performance at 270Mb/s and 1.485Gb/s, and 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. The sensitivity of the carrier detect can be easily programmed to allow
the GS1674 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 GS1674 is footprint and drop-in compatible with existing GS1574A and LMH0044 designs, with no additional
application changes required.
Key Features
• Replaces the LMH0044
• SMPTE 292M, SMPTE 344M and SMPTE 259M
compliant
• Automatic cable equalization
• Performance optimized for 270Mb/s and 1.485Gb/s.
Typical equalized length of Belden 1694A cable:
Š 220m 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
• 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)
• Drop-in compatible with the GS1574A. Forward
compatible with Gennum's 3G EQ products.
• Pb-free and RoHS compliant
Typical Application Circuit
CD
MUTE
VCC
VCC
6.8nH*
SDI
75Ω
10nF
1µF
1µF
16 15 14 13
1
VEE_A
2 _SDI
3
SDI
GS1674
VEE_D ¹²
11
SDO
10
SDO
10nF
75Ω
37.4Ω
4
VEE_A
9
VEE_D
4.7µF
+
+
4.7µF
56
78
1µF
SQ_ADJ
BYPASS
NOTE: All resistors in Ohms, capacitors in Farads,
and inductors in Henrys, unless otherwise noted.
* Value dependent on layout
SDO
SDO
GS1674 Adaptive Cable Equalizer
Data Sheet
54168 - 2
September 2012
www.semtech.com
1 of 16