MXIC MX27L256QC-12, MX27L256QC-15, MX27L256QC-20, MX27L256QC-25, MX27L256QI-12 Datasheet

FEATURES

CONTROL

LOGIC

OUTPUT

BUFFERS

Q0~Q7

CE
OE

A0~A14

ADDRESS

INPUTS

Y-DECODER

X-DECODER

Y-SELECT

256K BIT

CELL

MAXTRIX

VCC
GND

VPP

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MX27L256

256K-BIT [32Kx8] LOW VOLTAGE OPERATION

CMOS EPROM

• 32K x 8 organization

• Wide Voltage range, 2.7V to 3.6V DC

• +12.5V programming voltage

• Fast access time: 120/150/200/250 ns

• Totally static operation

GENERAL DESCRIPTION

The MX27L256 is a 256K-bit, ultraviolet Erasable Pro­grammable Read Only Memory. It is organized as 32K
by 8 bits, operates from a single + 3volt supply, has a
static standby mode, and features fast single address
location programming. All programming signals are TTL
levels, requiring a single pulse. For programming from
outside the system, existing EPROM programmers

PIN CONFIGURATIONS

VCC
A14
A13
A8
A9
A11
OE
A10
CE
Q7
Q6
Q5
Q4
Q3

PLCC

A7

A12

4

5

A6
A5
A4
A3

9

A2
A1
A0

NC

13

Q0

14 17 20

Q1

Q2

VPPNCVCC

1

32

MX27L256

NC

GND

A14

A13

30

29

25

21

Q3Q4Q5

PDIP

VPP

A12

A7
A6
A5
A4
A3
A2
A1
A0
Q0
Q1
Q2

GND

1
2
3
4
5
6
7
8
9
10
11
12
13
14

28
27
26
25
24
23
22
21
20

MX27L256

19
18
17
16
15

• Completely TTL compatible

• Operating current: 10mA @ 3.6V, 5MHz

• Standby current: 10uA

• Package type:

- 28 pin plastic DIP

- 32 pin PLCC

- 28 pin 8 x 13.4mm TSOP(I)

may be used. The MX27L256 supports intelligent fast
programming algorithm which can result in program­ming time of less than ten seconds.

This EPROM is packaged in industry standard 28 pin
dual-in-line packages, 32 lead PLCC, and 28 lead
TSOP(I) packages.

BLOCK DIAGRAM

A8
A9
A11
NC
OE
A10
CE
Q7
Q6

8 x 13.4mm 28 -TSOP(I)

22

OE

23

A11

24

A9

25

A8

26

A13

27

A14
VCC
VPP

P/N: PM0248

A12

A7
A6
A5
A4
A3

28
1
2
3
4
5
6
7

PIN DESCRIPTION

21

A10

20

CE

19

Q7

18

Q6

17

Q5

16

Q4

15

MX27L256

Q3

14

GND

13

Q2

12

Q1

11

Q0

10

A0

9

A1

8

A2

1

SYMBOL PIN NAME

A0~A14 Address Input
Q0~Q7 Data Input/Output
CE Chip Enable Input
OE Output Enable Input
VPP Program Supply Voltage
NC No Internal Connection
VCC Power Supply Pin
GND Ground Pin

REV. 3.3, SEP. 19, 2001

MX27L256

FUNCTIONAL DESCRIPTION

THE PROGRAMMING OF THE MX27L256

When the MX27L256 is delivered, or it is erased, the
chip has all 256K bits in the "ONE" or HIGH state.
"ZEROs" are loaded into the MX27L256 through the
procedure of programming.

For programming, the data to be programmed is applied
with 8 bits in parallel to the data pins.

VCC must be applied simultaneously or before VPP, and
removed simultaneously or after VPP. When
programming an MXIC EPROM, a 0.1uF capacitor is
required across VPP and ground to suppress spurious
voltage transients which may damage the device.

FAST PROGRAMMING

The device is set up in the fast programming mode when
the programming voltage VPP = 12.75V is applied, with
VCC = 6.25 V and OE = VIH (Algorithm is shown in
Figure 1). The programming is achieved by applying a
single TTL low level 100us pulse to the CE input after
addresses and data line are stable. If the data is not
verified, an additional pulse is applied for a maximum of
25 pulses. This process is repeated while sequencing
through each address of the device. When the
programming mode is completed, the data in all address
is verified at VCC = VPP = 5V ± 10%.

PROGRAM INHIBIT MODE

Programming of multiple MX27L256s in parallel with
different data is also easily accomplished by using the
Program Inhibit Mode. Except for CE and OE, all like
inputs of the parallel MX27L256 may be common. A
TTL low-level program pulse applied to an MX27L256
CE input with VPP = 12.5 ± 0.5 V and OE HIGH will
program that MX27L256. A high-level CE input inhibits
the other MX27L256s from being programmed.

PROGRAM VERIFY MODE

Verification should be performed on the programmed
bits to determine that they were correctly programmed.
The verification should be performed with CE and OE
at VIL, and VPP at its programming voltage.

AUTO IDENTIFY MODE

The auto identify mode allows the reading out of a binary
code from an EPROM that will identify its manufacturer
and device type. This mode is intended for use by
programming equipment for the purpose of
automatically matching the device to be programmed
with its corresponding programming algorithm. This
mode is functional in the 25°C ± 5°C ambient
temperature range that is required when programming
the MX27L256.

To activate this mode, the programming equipment
must force 12.0 ± 0.5 (VH) on address line A9 of the
device. 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 auto identify mode.

Byte 0 ( A0 = VIL) represents the manufacturer code,
and byte 1 (A0 = VIH), the device identifier code. For the
MX27L256, these two identifier bytes are given in the
Mode Select Table. All identifiers for manufacturer and
device codes will possess odd parity, with the MSB (Q7)
defined as the parity bit.

READ MODE

The MX27L256 has two control functions, both of which
must be logically satisfied in order to obtain data at the
outputs. Chip Enable (CE) is the power control and
should be used for device selection. Output Enable
(OE) is the output control and should be used to gate
data to the output pins, independent of device selection.
Assuming that addresses are stable, address access
time (tACC) is equal to the delay from CE to output (tCE).
Data is available at the outputs tOE after the falling edge
of OE, assuming that CE has been LOW and addresses
have been stable for at least tACC - tOE.

STANDBY MODE

The MX27L256 has a CMOS standby mode which
reduces the maximum Vcc current to 10 uA. It is placed
in CMOS standby when CE is at VCC ± 0.3 V. The
MX27L 256 also has a TTL-standby mode which
reduces the maximum VCC current to 0.25 mA. It is
placed in TTL-standby when CE is at VIH. When in
standby mode, the outputs are in a high-impedance
state, independent of the OE input.

P/N:PM0248

2

REV.3.3, SEP. 19, 2001

MX27L256

TWO-LINE OUTPUT CONTROL FUNCTION

To accommodate multiple memory connections, a two­line control function is provided to allow for:

SYSTEM CONSIDERATIONS

During the switch between active and standby
conditions, transient current peaks are produced on the
rising and falling edges of Chip Enable. The magnitude

1. Low memory power dissipation,

2. Assurance that output bus contention will not
occur.

of these transient current peaks is dependent on the
output capacitance loading of the device. At a minimum,
a 0.1 uF ceramic capacitor (high frequency, low inherent

inductance) should be used on each device between
It is recommended that CE be decoded and used as the
primary device-selecting function, while OE be made a
common connection to all devices in the array and
connected to the READ line from the system control bus.
This assures that all deselected memory devices are in
their low-power standby mode and that the output pins
are only active when data is desired from a particular

VCC and GND to minimize transient effects. In addition,

to overcome the voltage drop caused by the inductive

effects of the printed circuit board traces on EPROM

arrays, a 4.7 uF bulk electrolytic capacitor should be

used between Vcc and GND for each eight devices. The

location of the capacitor should be close to where the

power supply is connected to the array.
memory device.

MODE SELECT TABLE

PINS

MODE CE OE A0 A9 VPP OUTPUTS

Read VIL VIL X X VCC DOUT
Output Disable VIL VIH X X VCC High Z
Standby (TTL) VIH X X X VCC High Z
Standby (CMOS) VCC±0.3V X X X VCC High Z
Program VIL VIH X X VPP DIN
Program Verify VI H VIL X X VPP DOUT
Program Inhibit VIH VIH X X V PP High Z
Manufacturer Code(3) VIL VIL VIL VH VCC C2H
Device Code(3) VIL VIL VIH VH VCC 10H

NOTES: 1. VH = 12.0 V ± 0.5 V

2. X = Either VIH or VIL

3. A1 - A8 = A10 - A14 = VIL(For auto select)

P/N:PM0248

4. See DC Programming characteristics for VPP voltage during
programming.

3

REV.3.3, SEP. 19, 2001

FIGURE 1. FAST PROGRAMMING FLOW CHART

MX27L256

ST AR T

ADDRESS = FIRST LOCATION

VCC = 6.25V
VPP = 12.75V

X = 0

PROGRAM ONE 100us PULSE

INTERACTIVE
SECTION

VERIFY SECTION

INCREMENT ADDRESS

FAIL

NO

INCREMENT X

X = 25?

NO

VERIFY BYTE

?

PASS

LAST ADDRESS

YES

VCC = VPP = 5.25V

VERIFY ALL BYTES

?

PASS

DEVICE PASSED

YES

FAIL

FAIL

DEVICE FAILED

P/N:PM0248

4

REV.3.3, SEP. 19, 2001

SWITCHING TEST CIRCUITS

MX27L256

DEVICE
UNDER

TEST

CL = 100 pF including jig capacitance

SWITCHING TEST WAVEFORMS

AC driving levels

AC TESTING: AC driving levels are 2.4V/0.4V for both commercial grade and industrial grade.

CL

6.2K ohm

2.0V
TEST POINTS

0.8V

INPUT

Input pulse rise and fall times are < 20ns.

1.8K ohm
+5V

DIODES = IN3064
OR EQUIVALENT

2.0V

0.8V

OUTPUT

P/N:PM0248

5

REV.3.3, SEP. 19, 2001