compact flash card (CF)
Compact Flash cards (protected spelling: CompactFlash) are small memory cards with dimensions of 36.4 mm x 42.8 mm, with thicknesses of 3.3 mm (Type I) and 5.0 mm (Type II). These cards are available with storage capacities of up to 512 gigabytes and data transfer rates of 167 MB/s. Their service life is more than 1,000,000 memory cycles.
CF cards with storage capacities below 2 GB operate with the FAT 16 file system, and above that with FAT 32. Data is erased, saved and read in small data blocks, which makes storage more flexible. The current consumption is about 0.5 mA in idle mode, and an average of 50 mA in read and write mode. The supply voltage is 3.3 V and 5 V and can be switched between the two voltages. As an interface, the CF card uses Parallel Advanced Technology Attachment( PATA) with a 50- pin connector.
CF memory card applications include personal computers, notebooks, PDAs, MP3 players, digital cameras, and industrial and medical applications.
Compact Flash cards can be inserted into a PC card adapter type I and type II (5 mm thickness) and thus be connected to the PC card bus. In addition, there are special card readers for flash memory that can handle several formats and can be connected directly to the USB bus
The different CF card versions
The CompactFlash specifications are published by the CompactFlash Association( CFA). The first version in 1994 CF 1.0 had a data rate of 8.3 megabytes per second (MB/s) and a storage capacity of 128 GB. It was followed by CF 2.0, which had a data transfer rate of 16.6 MB/s. CF 3.0 provides for faster transfer rates and has FAT32 as the file allocation table. In addition, Ultra- DMA( UDMA) with 33 MB/s and 66 MB/s are achieved with this version. The CF 3.0 card can also be password protected. The 2006 version of CF 4.0 features a data rate of 133 MB/s, UDMA-133. In the CF 5.0 version, the CompactFlash Association has removed the 137 gigabyte (GB) storage capacity limit. Theoretically, CF 5.0 can have a storage capacity of 144 petabytes( PB). In addition, the data rate has been increased to 450 MB/s. CF 6.0 dates from 2010 and has a data rate of 167 MB/s with Ultra-DMA (UDMA 7). Higher data rates are offered by the CFast card.
The Compact Flash card is manufactured by Xircom, SanDisk, 3Com, TDK, SimpleTech, Viking and others.