2. DEFINITION OF PENDRIVE
• A USB flash drive is a data storage device that
contains flash memory with an integrated Universal
Serial Bus (USB) interface.USB flash drives are
typically removable,and physically much smaller than
an optical disc
3. DESCRIPTION
1.A pen drive, or a USB flash drive, is a portable data-
storage device.
2.Most weight less than 30 grams
3.USB flash drives are often used for the same purposes
for which floppy disks or CDs were used, i.e., for
storage, back-up and transfer of computer files.
4. 4.USB flash drives use the USB mass storage
standard, supported natively by modern operating
systems such as Linux,OS X,Windows and other
Unix-like systems, as well as many BIOS boot ROMs.
It can be read by many other systems such as the
Xbox 360,PlayStation 3,4
5. COMPONENTS INVOLVED
• A flash drive consists of a small printed circuit
board carrying the circuit elements and a USB
connector, insulated electrically and protected inside
a plastic or metal.
• There are typically four parts to a flash drive:
• Standard-A USB plug.
6. • USB mass storage controller
• NAND flash memorychip(s)
• Crystal oscillator
• Cover -Made of plastic or metal-to protect
the electronics against mechanical stress and shortcircuit
• /
7. ADDITIONAL COMPONENTS
• The typical device may also include:
• Jumpers and test pins - for testing during the flash drive's
manufacturing or loading code into the microprocessor.
• LEDs - indicate data transfers or data reads and writes.
• Write-protect switches - Enable or disable writing of data
into memory.
• Unpopulated space - provides space to include a second
memory chip.
9. CONTROLLER
• PC/Laptop and the flash memory (EEPROM) of the pendrive.
• It is fully compatible with USB 2.0 protocols and USB Mass storage
classV1.0 specification and it is IC SK6211 controller
• The devices like memorycard, hard disk, pendrive etc with high data
storage capacity fall under the category of Mass Storage Devices
•
10. MEMORY CHIP 1
• The chip which is shown in the image is a NAND type
flash memory which has fast read, write and erase
cycles. The data is stored in memory cells of the
EEPROM. The storage capacity of this memory is
based capacity bit.There is another similar chip with
storage capacity
11. MEMORY CHIP
• The image shows the other side of PCB. The second
memory chip, a crystal oscillator and a number of
surface mount components are soldered which are
required for the operation of the pen drive.
12. CRYSTAL OSCILLATOR
• The crystal oscillator produces the clock signal for the
correct operation of the device. The crystal oscillator
used here runs at a clock frequency at 12 MHz.
13. ADVANTAGES
• Lightweight and portable
• Shock and scratch resistant
• Ineffective by magnetic fields.
• Memory is non Volatile
• Plug-in friendly
• Data transfer friendly
14. DISADVANTAGES
• Small easy to lost
• Can be infected by computer virus
• Limited time of use
• Flash drive can physically be worn out.
