Dual output sine wave to logic converter has under 200 fsec jitter

April 09, 2013 // By Graham Prophet
Linear Technology's LTC6957 is a DC to 300MHz dual output buffer/driver/logic translator, 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, Linear says.

The LTC6957 converts any DC to 300MHz reference frequency into dual LVPECL, LVDS or CMOS outputs with low additive jitter of 45 fsecRMS (LVPECL) over the 12 kHz to 20 MHz integration bandwidth and less than 200 fsecRMS 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 4-7 dB.

While the LTC6957 can be used to convert any signal type to a logic level signal, it performs particularly well with sine waves. The selectable, band-limited input stage enables optimal conversion of sine waves with the lowest additive jitter. Use it in systems that distribute system clock references for board level synchronisation, and as a clock driver for analogue-to-digital converters (ADCs), digital-to-analogue converters (DACs) or DDS (direct digital synthesis) ICs with clock rates up to 300MHz.

LTC6957-1 provides two LVPECL outputs, LTC6957-2 provides two LVDS logic outputs, and LTC6957-3 and LTC6957-4 offer two in-phase CMOS or complementary CMOS outputs, respectively, with output skew as low as 3 psec (typ). Each device is available in small 12-pin MSOP or 3 x 3mm 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 costs $3.60 (1,000). More at www.linear.com/product/LTC6957