Texas Instruments LMK61E2EVM, User Manual

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Using the USB Interface Connection
7 Using the USB Interface Connection
The on-board MSP430F5529 USB microcontroller (U4) provides an I
2
C host interface to the LMK61E2
slave device. The device registers can be controlled via USB using the GUI platform running on a Host
PC.
8 EVM Quick Start Guide
The following guide allows the user to quickly configure the LMK61E2 to evaluate performance and device
flexibility
• 1. Set the Control Pin jumpers to the default configuration as noted in Table 1Table 3.
• 2. Confirm the EVM Default power configuration is set per Table 2 to power the LMK61E2 in USB
POWER mode using the on-board LDO regulators and power supplied over USB.
• 3. Observe any active output clock on OUTN and OUTP SMA ports.
– 3.1. Default EVM configuration is AC coupled LVPECL as noted in Table 4.
– 3.2. Use 50-ohm coax cables to connect the test equipment to the output SMA ports. If making a
single-ended measurement, terminate the unused SMA port with a 50-ohm load.
– 3.3. Power LEDs, D3 & D5 should be illuminated when the EVM is connected to power
– 3.4. I
2
C activity can be seen on LED D4 (active with activity).
• 4. Refer to Table 5 for recommended device configurations configurable via the GUI.
Table 5. Recommended Device Configurations
(1)
PARAMETER 156.25 MHz
(2)
100 MHz 161.1328125 MHz
PLL Reference Doubler Enabled
N Divider 50 48 51
Fractional Numerator 22500
Fractional Denominator 40000
VCO frequency 5000 MHz 4800 MHz 5162.25 MHz
Output Divider 32 16 32
Loop Filter Charge Pump Gain 6.4 mA 2.8 mA
Loop Filter Order 2nd Order 3rd Order
C1 5 pF 105 pF
C2 10 nF
C3 0 pF 35 pF
R2 800 Ω 1.1 k Ω
R3 18 Ω 1.3 k Ω
Modulator Order Integer Mode 1st Order
Dithering Disable Weak
Charge Pump Bleed None 8.5 k Ω 1 ns
(1)
Termination schemes should match device settings. See Table 4 .
(2)
Device default
9 Recommended Test Instruments
For making accurate measurements on ultra-low noise/jitter, high-speed clock signals, the following
instruments are recommended:
• Source Signal Analyzer: Keysight/Agilent E5052 for phase noise/jitter measurements
• Oscilloscope: Agilent DSA90000A series (or equivalent) for AC measurements and time-domain jitter
analysis with jitter software package
• Balun: M/A-COM H-183-4 (30-3000 MHz) 180° coupler, or equivalent
11 SNAU188 – October 2015 LMK61E2EVM User's Guide
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