Electronic Components Datasheet Search |
|
M87C257-20XF3TR Datasheet(PDF) 9 Page - STMicroelectronics |
|
M87C257-20XF3TR Datasheet(HTML) 9 Page - STMicroelectronics |
9 / 13 page Electronic Signature The Electronic Signature (ES) mode allows the reading out of a binary code from an EPROM that will identify its manufacturer and type. This mode is intended for use by programming equipment to automatically match the device to be programmed with its corresponding programming algorithm. The ES mode is functional in the 25 °C ± 5°C ambient temperature range that is required when program- ming the M87C257. To activate the ES mode, the programming equip- ment must force 11.5V to 12.5V on address line A9 of the M87C257, with VCC = VPP = 5V. Two identifier bytes may then be sequenced from the device outputs by toggling address line A0 from VIL to VIH. All other address lines must be held at VIL during Electronic Signature mode. Byte 0 (A0=VIL) repre- sents the manufacturer code and byte 1 (A0=VIH) the device identifier code. When A9 = VID, AS need not be toggled to latch each identifier address. For the SGS-THOMSON M87C257, these two identi- fier bytes are given in Table 4 and can be read-out on outputs Q0 to Q7. ERASURE OPERATION (applies for UV EPROM) The erasure characteristics of the M87C257 is such that erasure begins when the cells are exposed to light with wavelengths shorter than approximately 4000 Å. It should be noted that sunlight and some type of fluorescent lamps have wavelengths in the 3000-4000 Å range. Research shows that constant exposure to room level fluorescent lighting could erase a typical M87C257 in about 3 years, while it would take approximately 1 week to cause erasure when exposed to direct sunlight. If the M87C257 is to be exposed to these types of lighting conditions for extended periods of time, it is suggested that opaque labels be put over the M87C257 window to prevent unintentional erasure. The recommended erasure procedure for the M87C257 is exposure to short wave ultraviolet light which has wavelength 2537Å. The integrated dose (i.e. UV intensity x exposure time) for erasure should be a minimum of 15 W-sec/cm2. The erasure time with this dos- age is approximately 15 to 20 minutes using an ultraviolet lamp with 12000 µW/cm2 power rating. The M87C257 should be placed within 2.5 cm (1 inch) of the lamp tubes during the erasure. Some lamps have a filter on their tubes which should be removed before erasure. 9/13 M87C257 |
Similar Part No. - M87C257-20XF3TR |
|
Similar Description - M87C257-20XF3TR |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |