SNAS750B November 2020 – March 2021 LMK5C33216
PRODUCTION DATA
The programmable differential output driver can be programmed to achieve VOD swing compatible with LVDS, CML, LVPECL, and other differential receivers, respectively, across a 100-Ω differential termination. The differential output drivers can all be DC coupled or AC coupled.
The LVDS and HSDS differential drivers have internal biasing so external pullup or pulldown resistors should not be applied. External pulldown resistors are needed for LVPECL driver format. External pullup inductors and/or resistors are required for the open collector CML outputs.
The device has the ability to adjust DC offsets at the clock outputs for LVPECL, LVDS, and HSDS output formats. The range of DC common modes supported does vary some for each output type, due to internal output buffer structure limitations. DC common mode output voltages have a step size of around 100 mV. Some of the lower DC common mode voltages (0.4 to 0.6 V) may only be possible for LVPECL configured outputs. The ability to be able to DC couple was directly aimed at SYSREF output modes to support pulsed mode operation. Typically the differential output should be interfaced through external AC-coupling to a differential receiver with proper input termination and biasing for most clocking applications.
The differential multi-format drivers are available on all output channels (LVPECL, LVDS, HSDS formats) and can work up to 1 GHz. There will be minimal time delay offset change over temperature for all of the differential multi-format driver output modes, since they are all derived from roughly the same output buffer critical speed paths.
Open collector CML output modes of up to 2975 MHz are only supported on output channels 4 and 6, either in bypass mode from the VCO3 or VCO2 divide by 2 or 3 straight to those outputs.