SNLS558C April 2017 – May 2020 LMH0397
PRODUCTION DATA.
SDI_IO (in EQ Mode) and IN0 have a carrier detect circuit to monitor the presence or absence of an input signal. When the input signal amplitude for the selected input exceeds the carrier detect assert threshold, the LMH0397 operates in normal operation mode.
In the absence of an input signal, the LMH0397 automatically goes into Power Save Mode to conserve power dissipation. When a valid signal is detected, the LMH0397 automatically exits Power Save Mode and returns to the normal operation mode. If the ENABLE pin is pulled low, the LMH0397 is forced into Power-Down Mode. In Power Save Mode, both the carrier detect circuit and the serial interface remain active. In Power-Down Mode, only the serial interface remains active.
Users can monitor the status of the carrier detect through register programming. This can be done either by configuring the LOCK_N pin to output the CD_N status or by monitoring the carrier detect status register. See Table 4 for more details.
ENABLE | EQ/CD_SEL | SIGNAL INPUT | OPERATING MODE |
---|---|---|---|
H | L | 75-Ω video input at SDI_IO+ | EQ Mode, normal operation
Carrier detector at SDI_IO+ Serial interface active OUT0 automatically enabled, regardless of OUT0_SEL setting |
H | L | No signal at SDI_IO+ | Power Save Mode
Carrier detector at SDI_IO+ Serial interface active |
H | H | 100-Ω signal input at IN0± | CD Mode, normal operation
Carrier detector at IN0± Serial interface active |
H | H | No signal at IN0± | Power Save Mode
Carrier detector at IN0± Serial interface active |
L | X | Input signal ignored | Power-Down Mode
Forced device power down Serial interface active |