4.3.1 Slew Rate Selection (Rise/Fall Time Requirement)
The GS2988 supports two user-selectable output slew rates.
Control of the slew rate is determined by the setting of the SD/HD input pin.
Table 4-2: Slew Rate Selection
SD/HD
Rise/Fall Time
0
1
SMPTE 424M & 292M compliant
SMPTE 259M compliant
Floating
SMPTE 259M compliant
4.4 Output Disable
The GS2988 supports an output disable function for the serial data differential output.
Control of this function is determined by the setting of the DISABLE control pin.
The serial output disable (DISABLE), disables power to the entire device. When asserted
LOW, the SDO/SDO output driver is powered-down.
Table 4-3: Output Disable
DISABLE
SDO/SDO
0
1
All chip power-down
Operational
Floating
Operational
4.5 Output Signal Presence Indicator (OSP)
The GS2988 supports an output signal presence indicator function.
The output signal presence pin (OSP) is an active-low output that indicates when a valid
output signal has been detected at the pre-driver output.
The output signal presence function measures signal-edge energy to indicate that the
pre-driver to the serial data outputs is toggling.
GS2988
Final Data Sheet
11 of 18
Semtech
www.semtech.com
Rev.6
GENDOC-052131 July 2015
SEMTECH [ SEMTECH CORPORATION ]
