M27V801 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

M27V801

8 Mbit (1Mb x8) Low Voltage UV EPROM and OTP EPROM

STMicroelectronics 

M27V801

On-Board Programming

The M27V801 can be directly programmed in the

application circuit. See the relevant Application

Note AN620.

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 am-

bient temperature range that is required when pro-

gramming the M27V801. To activate the ES mode,

the programming equipment must force 11.5V to

12.5V on address line A9 of the M27V801. 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) represents the manufacturer code

and byte 1 (A0=VIH) the device identifier code. For

the STMicroelectronics M27V801, these two iden-

tifier bytes are given in Table 4 and can be read-

out on outputs Q0 to Q7. Note that the M27V801

and M27C801 have the same identifier bytes.

ERASURE OPERATION (applies to UV EPROM)

The erasure characteristics of the M27V801 is

such that erasure begins when the cells are ex-

posed to light with wavelengths shorter than ap-

proximately 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

M27V801 in about 3 years, while it would take ap-

proximately 1 week to cause erasure when ex-

posed to direct sunlight. If the M27V801 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 M27V801 window to

prevent unintentional erasure. The recommended

erasure procedure for the M27V801 is exposure to

short wave ultraviolet light which has wavelength

2537 Å. The integrated dose (i.e. UV intensity x

exposure time) for erasure should be a minimum

of 30 W-sec/cm2. The erasure time with this dos-

age is approximately 30 to 40 minutes using an ul-

traviolet lamp with 12000 µW/cm2 power rating.

The M27V801 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.

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