The LTC6957, a DC to 300MHz dual output buffer/driver/logic translator from Linear Technology Corporation, is suited for converting sine waves into low phase noise logic level signals. Prior solutions were unable to perform this conversion without introducing a significant amount of jitter. The LTC6957 converts any DC to 300MHz reference frequency into dual LVPECL, LVDS or CMOS outputs with exceptionally low additive jitter of 45fsRMS (LVPECL) over the 12 kHz to 20 MHz integration bandwidth and less than 200 fsRMS total jitter. The device also features a proprietary, selectable, input stage bandwidth-limiting feature, which substantially improves the additive phase noise for slow slewing signals by 4 to 7 dB.
While the LTC6957 can be used to convert any signal type to a logic level signal, it particularly excels with sine waves. The selectable, band-limited input stage enables optimal conversion of sine waves with the lowest additive jitter. The device is ideal for systems that distribute system clock references for board level synchronization. It can also be used as a clock driver for analog-to-digital converters (ADCs), digital-to-analog converters (DACs) or DDS (direct digital synthesis) ICs with clock rates up to 300MHz.
The LTC6957 is offered in four output logic signal types: the LTC6957-1 provides two LVPECL outputs, the LTC6957-2 provides two LVDS logic outputs, and the LTC6957-3 and LTC6957-4 offer two in-phase CMOS or complementary CMOS outputs, respectively, with output skew as low as 3ps (typ). Each device is available in small RoHS-compliant 12-pin MSOP or 3 mm x 3 mm DFN packages and can be ordered in industrial and automotive grades, supporting operating temperature ranges from -40 °C to 85 °C and -40 °C to 125 °C, respectively. The LTC6957 is in production, priced starting at $3.60 each in 1,000-piece quantities.