EPROM

What is EPROM?
EPROM stands for erasable programmable read only memory and is a type of solid state memory chip that retains its memory contents without the help of a power supply.
The basic transistor device in an EPROM is different from the normal MOS transistor. A floating gate avalanche injection MOS transistor is used. There are two gates to this MOS transistor. One is a floating gate, meaning that it has no electrical connection to that gate.
Types of solid state memory available with different desirable characteristics:
ROM
Read Only Memory, non-volatile (memory contents are retained even without the help of a power supply), are low power and high density.
RAM
Random Access Memory is volatile.
PROM
Programmable ROM allows you to write your own content or program. It cannot be erased so you can only program it once.
EPROM
You can erase whatever you have programmed and can reprogram it thus allowing it to be reused. It can be erased with ultra violet (UV) light which basically means that you have to take the chip out from the circuit and expose the memory chip to UV lights. These memory chips come with a particular package which enables this to happen. Standard room lighting cannot be used to erase the chip as it does not have enough UV light, however bright sunlight can cause erasure therefore this is why the window is protected with a label. There is a glass window on top which you can expose these memory cells to UV light. Once this happens the electrons which are in the floating gate, get excited because of the high energy they acquire and they overcome the silicon dioxide barrier and move over to the silicon substrate or the control gate and once they do this you are reducing the threshold voltage. This can take up to 30 minutes in which you have to expose it to UV light, after which the electrons move out from the floating gate and then it is ready for reprogramming.
Disadvantages of EPROM is that it takes time to erase the entire content. You don’t have control over which bits you want erased.
Differences between EPROM and EEPROM
EEPROM (electrically erasable programmable ROM) can be erased electrically and can be reprogrammed. The device it uses is called FLOTOX (Floating Gate Tunnelling Oxide) MOS. It is more flexible than EPROM, for example you can erase a single bit of memory internally at a time without removing the chip. There are also two transistors per cell instead of one so the density of an EEPROM is slightly less compared to the normal EPROM.

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Description Price Memory Size Organisation Interface Type Maximum Random Access Time Programming Voltage Reprogramming Technique In System Programmability Mounting Type Package Type Pin Count Dimensions Height Length Maximum Operating Supply Voltage
RS庫存編號 540-4845
製造零件編號DS2505+
HK$24.46
單位
16kbit - - - - - - Through Hole TO-92 3 - 4.95mm - -
RS庫存編號 169-8319
製造零件編號DS2505+
HK$20.54
毎管:10 個
單位
16kbit - - - - - - Through Hole TO-92 3 - 4.95mm - -
RS庫存編號 127-4051
製造零件編號AT27C020-55JU
BrandMicrochip
HK$21.15
/個 (每包:2個)
單位
2Mbit 256K x 8 bit - 55ns - OTP - Through Hole PLCC 32 14.04 x 11.5 x 3.17mm 3.17mm 14.04mm -
RS庫存編號 127-6561
製造零件編號AT27C4096-90JU
BrandMicrochip
HK$44.46
單位
4Mbit 256K x 16 bit - 90ns - OTP - Through Hole PLCC 44 16.66 x 16.66 x 4.06mm 4.06mm 16.66mm -
RS庫存編號 540-4839
製造零件編號DS2502+
HK$18.59
單位
1kbit - - - - - - Through Hole TO-92 3 4.95 (Dia.) x 3.94mm 3.94mm - -
RS庫存編號 127-6565
製造零件編號AT27C512R-70JU
BrandMicrochip
HK$13.19
/個 (每包:5個)
單位
512kbit 64K x 8 bit - 70ns - OTP - Through Hole PLCC 32 14.04 x 11.5 x 3.17mm 3.17mm 14.04mm -
RS庫存編號 127-4058
製造零件編號AT27C020-55PU
BrandMicrochip
HK$23.335
/個 (每包:2個)
單位
2Mbit 256K x 8 bit - 55ns - OTP - Through Hole PDIP 32 42.29 x 13.97 x 4.44mm 4.44mm 42.29mm -
RS庫存編號 127-6566
製造零件編號AT27C512R-70PU
BrandMicrochip
HK$12.722
/個 (每包:5個)
單位
512kbit 64K x 8 bit - 70ns - OTP - Through Hole PDIP 28 37.33 x 13.97 x 4.44mm 4.44mm 37.33mm -
RS庫存編號 177-1855
製造零件編號AT27LV512A-90JU
BrandMicrochip
HK$16.10
/個 (每包:5個)
單位
512kbit 64K x 8 bit Parallel 90ns - OTP - Surface Mount PLCC 32 14.04 x 11.5 x 3.17mm 3.17mm 14.04mm 3.6 (Low Voltage) V, 5 (Standard) V
RS庫存編號 172-9358
製造零件編號DS1982-F5+
HK$24.00
毎管:100 個
單位
- - - - - - - - F5 MicroCan 2 17.35 (Dia.) x 5.89mm 5.89mm - -
RS庫存編號 146-1071
製造零件編號DS2502P+
HK$15.49
毎管:120 個
單位
1kbit - - - - - - Surface Mount TSOC 6 4 x 3.89 x 1.5mm 1.5mm - -
RS庫存編號 127-4049
製造零件編號AT27C010-70PU
BrandMicrochip
HK$15.928
/個 (每包:5個)
單位
1Mbit 128K x 8 bit - 70ns - OTP - Through Hole PDIP 32 42.29 x 13.97 x 4.44mm 4.44mm 42.29mm -
全新
RS庫存編號 192-1254
製造零件編號DS1982-F3+
HK$29.671
個 (以毎袋:100)
單位
- - - - - - - - F3 MicroCan 2 17.36 (Dia.) x 3.1mm 3.1mm - -
RS庫存編號 177-1720
製造零件編號AT27C2048-55JU
BrandMicrochip
HK$30.31
/個 (每包:2個)
單位
2Mbit 128K x 16 bit Parallel 55ns - OTP - Surface Mount PLCC 44 16.66 x 16.66 x 4.06mm 4.06mm 16.66mm 5 V
RS庫存編號 127-6563
製造零件編號AT27C512R-45JU
BrandMicrochip
HK$13.19
/個 (每包:5個)
單位
512kbit 64K x 8 bit - 45ns - OTP - Through Hole PLCC 32 14.04 x 11.5 x 3.17mm 3.17mm 14.04mm -
全新
RS庫存編號 192-1488
製造零件編號DS1982-F3+
HK$39.53
/個 (每包:2個)
單位
- - - - - - - - F3 MicroCan 2 17.36 (Dia.) x 3.1mm 3.1mm - -
RS庫存編號 127-6551
製造零件編號AT27C1024-45JU
BrandMicrochip
HK$21.58
/個 (每包:2個)
單位
1Mbit 64K x 16 bit - 45ns - OTP - Through Hole PLCC 44 16.66 x 16.66 x 4.06mm 4.06mm 16.66mm -
RS庫存編號 127-6564
製造零件編號AT27C512R-45PU
BrandMicrochip
HK$12.898
/個 (每包:5個)
單位
512kbit 64K x 8 bit - 45ns - OTP - Through Hole PDIP 28 37.33 x 13.97 x 4.44mm 4.44mm 37.33mm -
RS庫存編號 127-4061
製造零件編號AT27C020-90JU
BrandMicrochip
HK$23.38
/個 (每包:2個)
單位
2Mbit 256K x 8 bit - 90ns - OTP - Through Hole PLCC 32 14.04 x 11.5 x 3.17mm 3.17mm 14.04mm -
RS庫存編號 127-6562
製造零件編號AT27C4096-90PU
BrandMicrochip
HK$50.19
單位
4Mbit 256K x 16 bit - 90ns - OTP - Through Hole PDIP 40 52.57 x 13.97 x 4.44mm 4.44mm 52.57mm -