5V
VDD: Select
3.3 V LDO1
LDO2 Output
Voltage (1.8 V)
VCCXO:
Select 3.3 V
from LDO3
VDDO:
Select LDO2
Out Voltage
EVM Configuration
14
SNAU236A – June 2018 – Revised December 2018
Copyright © 2018, Texas Instruments Incorporated
LMK05318EVM User's Guide
On the EVM, the default power configuration uses the onboard LDO regulators to power all VDD and
VDDO pins from an external 5-V supply input VIN1 to J1 (or J2). A Dual LDO regulator (U3) is used to
power the VDD and VDDO rails of the DUT and its peripheral circuitry. A separate LDO regulator (U4),
also supplied from VIN1, is used to power the onboard XO circuits.
NOTE:
Not every power connection is used or required to operate the EVM. Other power
configurations are possible. See the power schematics in
,
, and
shows the default power jumper locations and settings.
Figure 4. Default Power Jumper Configuration
shows the suggested power configurations for the DUT.
(1)
The SMA ports J2 or J3 can be used to power VIN1 or VIN2, respectively, through a coaxial cable instead of using power cables
to J1.
Table 6. Suggested DUT Power Configurations
CONNECTION
NAME
ONBOARD LDO REGULATORS
(DEFAULT)
DIRECT EXTERNAL SUPPLIES
VDD = 3.3 V (LDO1)
VDDO = 1.8 / 2.5 / 3.3 V (LDO2)
VDD = 3.3 V (EXT. VIN1)
VDDO = 1.8 / 2.5 / 3.3 V (EXT. VIN2)
J1
(1)
PWR
Pin 1 (VIN1): Connect to external 5-V supply
Pin 2 (VIN2): n/a
Pin 3 (VIN3): n/a
Pin 4 (GND): Connect to supply ground
Pin 1 (VIN1): Connect to external 3.3-V supply
Pin 2 (VIN2): Connect to external 1.8-V, 2.5-V,
or 3.3-V supply
Pin 3 (VIN3): n/a
Pin 4 (GND): Connect to supply ground
JP1
VDD
Tie pins 1-2: Selects 3.3 V from LDO1 to VDD
Plane
Tie pins 2-3:
Selects ext. 3.3V supply from VIN1 to VDD
Plane
JP2
VDDO
Tie pins 1-2: Selects LDO2 output to VDDO
Plane
Tie pins 2-3:
Selects ext. supply from VIN2 to VDDO Plane
JP4
VOUT2
Tie pins 1-2: LDO2 out = 1.8 V (default)
Tie pins 3-4: LDO2 out = 2.5 V
Tie pins 5-6: LDO2 out = 3.3 V
n/a