GS3140 Datasheet, PDF (15/40 Pages) Semtech Corporation – Multi-Rate Adaptive 3G SDI Equalizer

4.6 Rate Detection
The GS3140 will differentiate between 2.97Gb/s, 1.485Gb/s, 270Mb/s,
125Mb/s, and <125Mb/s. The detected data rate is reported using the
DETECTED_INPUT_RATE bits in STATUS_REG_0 accessible through the device’s host
interface.
Indication of the detected rate is also available on the interrupt (INT) status pin, as
selected using the INT_SOURCE_SELECT and INT_CD_MODE_SELECT bits in
INT_OUT_CONF_REG_0 accessible through the device‘s host interface.
4.7 Interrupt (INT)/ Status Output
The GS3140‘s programmable interrupt (INT) pin flags internal states, or changes of state
to the host system. The default function of this pin is Loss of Signal (LOS). Other
functions are programmed via the device‘s host interface. The additional functions
include:
• Rate change detection
• Detection of a specific data rate or set of rates
These functions are chosen using bits INT_SOURCE_SELECT, INT_CD_MODE_SELECT,
and DATA_RATE_DETECTION in the INT_OUT_CONF_REG_0 register.
4.8 Power Modes
4.8.1 Bypass
The GS3140 supports a mode of operation where the equalizer core and DC restoration
stages are bypassed. This mode is controlled by the settings of the BYPASS and
AUTO_BYPASS bits in EQ_CONF_REG_0 of the host interface.
No equalization or DC restoration occurs in BYPASS mode. These functions are disabled
in order to reduce power consumption of the device for signals that do not require
equalization and DC restoration. When the device is in BYPASS, the LOS continues to
function based on carrier detect.
In addition to Manual-BYPASS, Auto-BYPASS is also available. When the AUTO_BYPASS
bit in EQ_CONF_REG_0 is set to 1, BYPASS is initiated by detection of an input signal with
a data rate below MADI.
4.8.2 Sleep
The GS3140 features a SLEEP function that is controlled through the host interface.
When the part is in SLEEP mode, only carrier based Loss of Signal (LOS) detection
remains active. All other sections of the part are powered down.
When in SLEEP mode, the part consumes 13mW of total power.
GS3140
Final Data Sheet
PDS-060939
Rev.1
May 2015
www.semtech.com
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