15
SNAU210A – March 2017 – Revised March 2020
Copyright © 2017–2020, Texas Instruments Incorporated
SYSREF Feature
Appendix G
SNAU210A – March 2017 – Revised March 2020
SYSREF Feature
1. Configure TICS Pro
PLL
tab for SYSREF.
•
Check the
SYSREF_EN
box and
VCO_PHASE_SYNC
box.
•
Change
OUTB_MUX
to
SysRef
and uncheck the
OUT_PD
box.
•
Confirm the
Interpolator frequency
is between 800 MHz and 1500 MHz. If not, change the
SYSREF_DIV_PRE
drop-down to
Div2
or
Div4
.
•
To modify SYSREF frequency, change the value in the
SYSREF_DIV
box.
•
Go to
User Controls
in the side bar, make sure the
INPIN_IGNORE
box is unchecked.
2. Click the
Toggle SysRefReq Pin
box to initiate SYSREF.
Figure 20. SYSREF Example
Table 9. SYSREF Modes
MODE NAME
DESCRIPTION
TICS PRO - SYS REF SETTINGS
Master -
Continuos
LMX2594 generates SysRef pulses as long as
SysRefReq pin is held high.
Default mode. See quick start instructions
Master - Pulse
LMX2594 generates a finite number of pulses as long
as the SysRefReq pin is held high.
Note: SysRefReq
must be held high for the duration of the pulses.
• Uncheck
SysRefReq
under
Pins
in
User Controls
tab
• Check
SYSREF_PULSE
• Set
SYSREF_PULSE_CNT
to desired number of pulses
• Check
SysRefReq
under
Pins
in
User Controls
tab
Repeater
RFOUTB will repeat external input to SysRefReq pin.
Output will be reclocked to LMX2594 internal
frequency
• Uncheck
SysRefReq
• Check
SysRef_Repeat
