M87C257 STMICROELECTRONICS | Alldatasheet
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256K (32K x 8) UV EPROM and OTP EPROM June 1996 1/13 AI00928B A0-A14 ASV PP Q0-Q7 VCC M87C257 G E VSS Figure 1. Logic Diagram PROGRAMMING TIMES of AROUND 3sec.
DESCRIPTION
The M87C257 is a high speed 262,144 bit UV erasable and electrically programmable EPROM. The M87C257 incorporates latches for all address inputs to minimize chip count, reduce cost, and simplify the design of multiplexed bus systems. The Window Ceramic Frit-Seal Dual-in-Line pack- age has a transparent lid which allows the user to expose the chip to ultraviolet light to erase the bit pattern. A new pattern can then be written to the device by following the programming procedure. For applications where the content is programmed only one time and erasure is not required, the M87C257 is offered in Plastic Leaded Chip Carrier, package. A0 - A14 Address Inputs Q0 - Q7 Data Outputs E Chip Enable G Output Enable ASV PP Address Strobe / Program Supply VCC Supply Voltage VSS Ground Table 1. Signal Names
Warning: NC = Not Connected, DU = Dont’t Use.
1 ASV PP
control and should be used for device selection.
- Minimum DC voltage on Input or Output is –0.5V with possible undershoot to –2.0V for a period less than 20ns. Maximum DC
voltage on Output is VCC +0.5V with possible overshoot to VCC +2V for a period less than 20ns. Table 2. Absolute Maximum Ratings (1)
Table 3. Operating Modes Table 4. Electronic Signature dresses have been stable for at least tAVQV -tGLQV . is desired from a particular memory device.
Notes:1. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP .
- Maximum DC voltage on Output is VCC +0.5V.
Table 7. Read Mode DC Characteristics (1) Notes:1. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP .
- Sampled only, not 100% tested.
- In case of 45ns speed see High Speed AC measurement conditions.
Notes:1. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP .
- Sampled only, not 100% tested.
Figure 5. Read Mode AC Waveforms
Note: 1. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP . Table 9. Programming Mode DC Characteristics (1) Table 10. Programming Mode AC Characteristics (1)
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 V CC = VPP = 5V. Two identifier bytes may then be sequenced from the device outputs by toggling address line A0 from V IL 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/cm 2. The erasure time with this dos- age is approximately 15 to 20 minutes using an ultraviolet lamp with 12000 µW/cm 2 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. M87C257
ORDERING INFORMATION SCHEME Note: 1. High Speed, see AC Characteristics section for further information. For a list of available options (Speed, VCC Tolerance, Package, etc...) refer to the current Memory Shortform catalogue. For further information on any aspect of this device, please contact the SGS-THOMSON Sales Office nearest to you. Speed -45 (1) 45 ns -60 60 ns -70 70 ns -80 80 ns -90 90 ns -10 100 ns -12 120 ns -15 150 ns -20 200 ns VCC Tolerance X ± 5% blank ± 10% Package F FDIP28W C PLCC32 Temperature Range 1 0 to 70 °C 6 –40 to 85 °C 7 –40 to 105 °C 3 –40 to 125 °C Option X Additional Burn-in TR Tape & Reel Packing Example: M87C257 -70 X C 1 X M87C257
FDIP28W - 28 pin Ceramic Frit-seal DIP , with window FDIPW-a A L B1 B e1 D S E1 E N Cα eA Symb mm inches Typ Min Max Typ Min Max A 5.71 0.225 A1 0.50 1.78 0.020 0.070 A2 3.90 5.08 0.154 0.200 B 0.40 0.55 0.016 0.022 B1 1.17 1.42 0.046 0.056 C 0.22 0.31 0.009 0.012 D 38.10 1.500 E 15.40 15.80 0.606 0.622 E1 13.05 13.36 0.514 0.526 eA 16.17 18.32 0.637 0.721 L 3.18 4.10 0.125 0.161 S 1.52 2.49 0.060 0.098 α 4° 15° 4° 15° N2 8 2 8 FDIP28W Drawing is not to scale M87C257
PLCC32 - 32 lead Plastic Leaded Chip Carrier, rectangular PLCC D Ne E1 E 1 N Nd CP B D2/E2 e A Symb mm inches Typ Min Max Typ Min Max A 2.54 3.56 0.100 0.140 A1 1.52 2.41 0.060 0.095 B 0.33 0.53 0.013 0.021 B1 0.66 0.81 0.026 0.032 D 12.32 12.57 0.485 0.495 D1 11.35 11.56 0.447 0.455 D2 9.91 10.92 0.390 0.430 E 14.86 15.11 0.585 0.595 E1 13.89 14.10 0.547 0.555 E2 12.45 13.46 0.490 0.530 N3 2 3 2 Nd 7 7 Ne 9 9 CP 0.10 0.004 PLCC32 Drawing is not to scale M87C257
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics. © 1996 SGS-THOMSON Microelectronics - All Rights Reserved SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco - The Netherlands - Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. M87C257