Diff. RF
Output A
Diff. RF
Output B
LMX2594
Reference input
SE or Diff
Power supply
3.3 Volt
SYNC
SYSREF
Lock
indicator
LED
1: SPI read block
2: Lock indicator
Upper position = ON
Lower position = OFF
Loop filter
components
(*_LF)
Serial Interface Pin-out
2
4
6
8
10
1
3
5
7
9
(Optional)
Add a XO here
3.3 V supply
RFoutAP
Connect to
an analyzer
50
termination
Connect to
a PC
Clean 100 MHz
clock source
Reference Pro
board
LMX2594EVM
board
Conn
ect b
oth
seria
l inte
rface
toge
ther
OSCinM can be left
open
Evaluation Board Setup
3
SNAU210A – March 2017 – Revised March 2020
Copyright © 2017–2020, Texas Instruments Incorporated
LMX2594 EVM Instructions – 15-GHz Wideband Low Noise PLL With
Integrated VCO
1
Evaluation Board Setup
Figure 2. LMX2594EVM Setup
1. Power:
a. Set power supply to 3.3 V with 600-mA current limit and connect to V
CC
SMA.
2. Input Signal:
a. Connect a clean 100-MHz clock source to the OSCinP SMA.
3. Programming Interface:
•
Reference Pro will provide SPI interface to program LMX2594.
a. Connect USB cable from laptop or PC to USB port in Reference Pro. This provides power to
Reference Pro board and communication with TICS GUI.
b. Connect 10 pin ribbon cable from Reference Pro to LMX2594EVM as shown above.
4. Output:
a. Connect RFoutAM or RFoutAP to a phase noise analyzer. Connect a 50-
Ω
resistor on the unused
pin if you are using a single-ended output. Use a balun if you are using a differential output.
2
EVM Description
The LMX2594 is populated on a 4-layer PCB. This brief description should help you use the EVM:
Figure 3. LMX2594EVM Description
