JAJSHR0E March 2017 – July 2022 LMH1297
PRODUCTION DATA
The EQ/CD_SEL pin selects the I/O as either an input (EQ mode) or an output (CD mode). The logic level applied to the EQ/CD_SEL pin automatically powers down the unused I/O direction. For example, if the LMH1297 is in EQ mode (EQ/CD_SEL = L), then the SDI_IO cable driver is powered down.
EQ/CD_SEL | INPUT | MODE | NOTES |
---|---|---|---|
L | SDI_IO+ | EQ mode | 75-Ω video input to SDI_IO+. OUT0± automatically enabled. SDI_IO Cable Driver powered down. |
H | IN0± | CD mode | 100-Ω input to IN0±. SDI_IO+ enabled as a cable driver output. SDI_OUT programmable as a secondary cable driver output. SDI_IO Equalizer powered down. |
The EQ/CD_SEL pin should be strapped at power up for normal operation. After power up, the EQ/CD_SEL pin state can be dynamically changed from EQ mode to CD mode and vice versa. When changing the EQ/CD_SEL state after power up, the signal flow to the reclocker is momentarily disturbed, and the chip automatically initiates a CDR reset to relock to the new input signal.