Specifications

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The maximum theoretical capacity of a Compact Flash card is 137GB, but technical problems and
costs preclude any move to that capacity any time soon. There is pressure, however, to increase
the Compact Flash capacity to 16GB and beyond so that the cards can hold enough data to
replace miniDV digital video cassettes in digital camcorders. There are some significant
advantages of using flash memory in digital camcorders:
• Simpler mechanical requirements eliminate complex tape guidance and transport systems
and helical scanning heads.
• Transfer rates of video data are measured in seconds rather than real-time hours for tape.
• Flash memory cards are more tolerant of tough environmental conditions than tape.
• A 5-GB capacity matches that of recordable DVD discs.
The remaining problem is that eliminating the expensive tape mechanics of a digital video
camcorder would make the entire recording device far less expensive than the Compact Flash
medium it would use. Today’s 4GB Compact Flash cards are often more expensive than many of
today’s entry-level digital camcorders.
The Compact Flash card itself is a rugged plastic shell with two stainless-steel faces front and
back. The shell contains a small circuit board with a number of flash-memory chips as well as a
controller chip. The controller chip can speed up the transfer of data to and from the chip as well
as manage defects and correct errors that might occur during any transfer. The number of memory
chips on the internal circuit board determines the capacity of the card so that externally all of the
cards of the same type are the same physical size. Compact Flash has two rows of 25 pinholes on
the insertion end of the card into which contact pins reach the circuitry. The card has no pins that
can be bent and no exposed contacts that can be damaged.
The Compact Flash card also excels in writing speeds. The latest specification 4.1 supports data
writing speeds up to 133 MB/s. CF cards operate on a power supply of either 3.3 volts or 5.0 volts
and use only 5% of the power required for a small 1.8-inch or 2.5-inch disc drive. The cards are
five to ten times more rugged than disc drives, too: they can withstand a 10-foot drop to a hard
floor, a shock measured as 2,000 Gs of force. In terms of the ideal storage medium, Compact
Flash seemed to fill all the requirements except for its high initial cost when it was introduced. As
digital cameras grew in popularity, the popularity of the CF card grew along with them; and the
future points to their use as recording media for digital video.
CF+ is a design for other devices such as wireless communication cards and micro hard drives
such as the IBM Microdrive to use CompactFlash Type II slots and take advantage of the CF
protocol.
X-Ray of CompactFlash Card
Controller chip
Contact pins
NAND memory
chip