SDAA294 March   2026 LMK6B

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2The LMK6Bx BAW Oscillator
  6. 3TI Clock Buffers
    1. 3.1 The LMKDB1x LP-HCSL Buffer Family
    2. 3.2 The LMK1Dx LVDS Buffer Family
  7. 4Clocking LMKDB1x with LMK6Bx
    1. 4.1 Clocking LMKDB1x Buffer with a LP-HCSL Oscillator
  8. 5Clocking the LMK1Dx with the LMK6Bx
    1. 5.1 Clocking LMK1Dx Buffer with a LP-HCSL Oscillator
  9. 6Summary
  10. 7References

4 Clocking LMKDB1x with LMK6Bx

When clocking the LMKDB1x LP-HCSL buffer with the LMK6Bx, the LMKDB1x achieves best performance when using the LMK6BGx. The G in the OPN refers to HS-LVDS output type (VCM = 1.2V) with a custom swing of 1.6Vppd. Figure 4-1 demonstrates the correct termination to clock the LMKDB1x with the LMK6BGx. The LMK6BGx can replace any LVDS-type oscillator already on the board without any required changes.

LMK6BGx Termination Required to Drive the LMKDB1x LP-HCSL Buffer Figure 4-1 LMK6BGx Termination Required to Drive the LMKDB1x LP-HCSL Buffer

When clocking the LMKDB1x with the LMK6BGx, the total jitter of the clock tree results in 32.4fs at 312.5MHz and 22.4fs when using a 4MHz HPF. Table 4-1 summarizes the jitter of the LMK6BGx, the total jitter of the LMK6BGx clocking the LMKDB1x, and respective 4MHz high-pass filter (HPF) jitter. Figure 4-2 and Figure 4-3 showcase the respective phase noise curves.

Table 4-1 LMK6BGx and LMKDB1x Performance Summary (3.3V Supply)
Output Frequency (MHz) LMK6BGx RMS Jitter (fs)(1) LMK6BGx + LMKDB1x RMS Jitter (fs)(1) LMK6BGx 4MHz HPF RMS Jitter (fs)(1) LMK6BGx + LMKDB1x RMS Jitter (fs)(1)
156.25 39.7 49.7 30.5 37.0
312.5 25.3 32.4 16.0 22.4
(1) RMS jitter calculated from 12kHz to 20MHz integrated bandwidth.
LMK6BGx and LMK6BGx + LMKDB1x Phase Noise Curves at 156.25MHz and 3.3V Figure 4-2 LMK6BGx and LMK6BGx + LMKDB1x Phase Noise Curves at 156.25MHz and 3.3V
LMK6BGx and LMK6BGx + LMKDB1x Phase Noise Curves at 312.5MHz and 3.3V Figure 4-3 LMK6BGx and LMK6BGx + LMKDB1x Phase Noise Curves at 312.5MHz and 3.3V