DAC5670-SP Datasheet, PDF (21/30 Pages) Texas Instruments – 14-BIT 2.4-GSPS DIGITAL-TO-ANALOG CONVERTER

DAC5670-SP
www.ti.com
SGLS386A – JANUARY 2009 – REVISED DECEMBER 2009
Clock Input
The DAC5670 features differential, LVPECL compatible clock inputs (DACCLK_P, DACCLK_N). Figure 16shows
the equivalent schematic of the clock input buffer. The internal biasing resistors set the input common-mode
voltage to AVDD/2, while the input resistance is typically 1 kΩ. A variety of clock sources can be ac-coupled to
the device, including a sine wave source (see Figure 17).
Figure 16. Clock Equivalent Input
Figure 17. Driving the DAC5670 with a Single-Ended Clock Source Using a Transformer
To obtain best ac performance the DAC5670 clock input should be driven with a differential LVPECL or sine
wave source as shown in Figure 18and Figure 19. Here, the potential of VTT should be set to the termination
voltage required by the driver along with the proper termination resistors (RT). The DAC5670 clock input can also
be driven single-ended for slower clock rates using TTL/CMOS levels; this is shown in Figure 20.
Copyright © 2009, Texas Instruments Incorporated
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