The Genesys Logic GL823 is a USB 2.0 SD/MMC flash card reader single chip. It supports USB 2.0 high-speed transmission to Secure DigitalTM (SD), SDHC, SDXC, miniSD, microSD (T-Flash), MultiMediaCardTM (MMC), RS-MMC, MMCmicro, and MMCmobile on one chip. As a single chip solution for the USB 2.0 flash card reader, GL823 complies with universal serial bus specification rev. 2.0, USB storage class specification ver.1.0, and SD/MMC card interface specification. This Circuit Analysis Report provides hierarchical schematics of the Controlled Oscillator Core, the Clock Level Shifter and Frequency Divider and the CML-to-CMOS Converter.