The LMH1982 device is a multi-rate video clock generator ideal for use in a wide range of
3-Gbps (3G), high-definition (HD), and standard-definition (SD) video applications, such as video
synchronization, serial digital interface (SDI) serializer and deserializer (SerDes), video
conversion, video editing, and other broadcast and professional video systems.
The LMH1982 can generate two simultaneous SD and HD clocks and a Top of Frame (TOF)
pulse. In genlock mode, the device's phase locked loops (PLLs) can synchronize the output signals
to H sync and V sync input signals applied to either of the reference ports. The input reference
can have analog timing from Texas Instrument's LMH1981 multi-format video sync separator or digital
timing from an SDI deserializer and should conform to the major SD and HD standards. When a loss of
reference occurs, the device can default to free run operation where the output timing accuracy
will be determined by the external bias on the free run control voltage input.
The LMH1982 can replace discrete PLLs and field-programmable gate array (FPGA) PLLs with
multiple voltage controlled crystal oscillators (VCXOs). Only one 27.0000 MHz VCXO and loop filter
are externally required for genlock mode. The external loop filter as well as programmable PLL
parameters can provide narrow loop bandwidths to minimize jitter transfer. HD clock output jitter
as low as 40 ps peak-to-peak can help designers using FPGA SerDes meet stringent SDI output jitter
The LMH1982 is offered in a space-saving 5 mm × 5 mm 32-pin WQFN package and provides low
total power consumption of about 250 mW (typical).
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