Introduction
7
SLAU579D – June 2014 – Revised August 2018
Copyright © 2014–2018, Texas Instruments Incorporated
ADC3xxxEVM and ADC3xJxxEVM
Table 2. Power Supply Options
Device
Description
ADC32xx
JP6: 1-2, JP7: 1-2
Default connection for LDO 1.8-V supply, switch both to 2-3 to use the switcher U4, install R79 for 1.8-V
switcher output
ADC34xx
JP6: 1-2, JP7: 1-2
Default connection for LDO 1.8-V supply, switch both to 2-3 to use the switcher U4, install R79 for 1.8-V
switcher output
ADC342J/34Jxx
JP9: 1-2, JP10: 1-2
Default connection for LDO 1.8-V supply, switch both to 2-3 to use the switcher U8, install R152 for 1.8-V
switcher output
JP12: 1-2, JP13: 1-2
Default connection for LDO 3.3 V for LMK04828 power and onboard SPI/CPLD, switch both to 2-3 to use
U11 switcher output, install R163 for 3.3-V switcher output
The default power path has an efficient, dual-output, DC/DC switching power supply to first step down the
input supplies from 5 V to 4 V, and 2.8 V for the subsequent low-noise LDOs. The 4 V is used by an LDO
to derive 3.3 V for the LMK04828 clock circuits on the ADC3xJxx EVMs. The 2.8 V is used by an LDO to
derive a 1.8-V supply for the ADC and USB circuits.
The low-noise LDOs can be bypassed to allow the DC/DC power supply to directly provide the ADC
power. Note that the feedback resistors of the DC/DC converter must be adjusted accordingly. See the
respective ADC EVM user's guide schematic for details.