The Texas Instruments THS1041 is a 10-bit, 40-MSPS, high-speed analog-to-digital converter (ADC). For many years because of its low power dissipation and extended life, it has been used in various applications such as programmable gain amplifier and built-in clamp. With recent FPGA development, some application systems have been upgraded with a direct interface of the THS1041 to an FPGA, for example, by connecting I/O pins of the THS1041 to the I/O pins of Xilinx™ Spartan-3 or Altera™ program logic device (PLD). For such an interface, a power-on initial state should be considered in the interface design. Otherwise, the power-on initial state of the FPGA can affect the initial state of THS1041 and in some cases, affect the entire application system. In order to ensure the successful interfacing of the THS1041 to an FPGA, a test was conducted, and this application report presents those results.