The SSTUH32866 is a 1.8 V configurable register specifically designed for use on DDR2 memory modules requiring a parity checking function. It is defined in accordance with the JEDEC JESD82-7 standard for the SSTU32864 registered buffer, while adding the parity checking function in a compatible pinout. The JEDEC standard for SSTUH32866 is pending publication. The register is configurable (using configuration pins C0 and C1) to two topologies: 25-bit 1 : 1 or 14-bit 1 : 2, and in the latter configuration can be designated as Register A or Register B on the DIMM. The SSTUH32866 accepts a parity bit from the memory controller on its parity bit (PAR_IN) input, compares it with the data received on the DIMM-independent D-inputs and indicates whether a parity error has occurred on its open-drain QERR pin (active LOW). The convention is even parity, that is, valid parity is defined as an even number of ones across the DIMM-independent data inputs combined with the parity input bit.