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January 2000

M27W400

4 Mbit (512Kb x8 or 256Kb x16)

Low Voltage UV EPROM and OTP EPROM

s

2.7 to 3.6V LOW VOLTAGE in READ

OPERATION

s

READ ACCESS TIME:

s

BYTE-WIDE or WORD-WIDE

CONFIGURABLE

s

4 Mbit MASK ROM REPLACEMENT

s

LOW POWER CONSUMPTION

– Active Current 20mA at 8MHz

– Stand-by Current 15µA

s

PROGRAMMING VOLTAGE: 12.5V ± 0.25V

s

PROGRAMMING TIME: 50µs/word

s

ELECTRONIC SIGNATURE

– Manufacturer Code: 20h

– Device Code: B8h

DESCRIPTION

The M27W400 is a low voltage 4 Mbit EPROM of-

fered in the two range UV (Ultra Violet Erase) and

OTP (one time programmable). It is ideally suited

for microprocessor systems requiring large data or

program storage. It is organised as either 512

Kwords of 8 bit or 256 Kwords of 16 bit. The pin-

out is compatible with the most common 4 Mbit

Mask ROM.

The M27W400 operates in the read mode with a

supply voltage as low as 2.7V at –40 to 85°C tem-

perature range. The decrease in operating power

allows either a reduction of the size of the battery

or an increase in the time between battery re-

charges.

The FDIP40W (window ceramic frit-seal package)

has a transparent lid which allows the user to ex-

pose the chip to ultraviolet light to erase the bit pat-

tern. A new pattern can then be written to the

device by following the programming procedure.

For application where the content is programmed

only one time and erasure is not required, the

M27W400 is offered in PDIP40 and PLCC44 pack-

ages.

1

40

1

40

FDIP40W (F)

PDIP40 (B)

PLCC44 (K)

Figure 1. Logic Diagram

AI03096

18

A0-A17

BYTEVPP

Q0-Q14

VCC

M27W400

G

E

VSS

15

Q15A–1