ST M87C257 User Manual

256K (32K x 8) UV EPROM and OTP EPROM

INTEGRA TE D ADDRE SS LATCH
FA ST ACCESS TIME: 45ns
LOW POWER “CMOS” CONSUMPTION:
– Active Current 30mA
– Standby Current 100µA
PROGRAMMING VOLTAGE: 12.75V
ELECTRONI C S IG NATURE for AUTOM ATED

PROGRAMMING
PROGRAM MING T IM ES of ARO UND 3sec.

(PRESTO II ALGORITHM)

DESCRIP TION

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 pack­age 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 pr ogrammed
only one time and erasure is not required, the
M87C257 is offered in Plas tic Leaded Chip Carrier ,
package.

ADDRESS LATCHED

28

1

FDIP28W (F)

Figure 1. Logic Diag ra m

V

CC

15

A0-A14

E

M87C257

M87C257

PLCC32 (C)

8

Q0-Q7

G

T able 1. Signal Names

A0 - A14 Address Inputs
Q0 - Q7 Data Outputs
E Chip Enable
G Output Enable
ASV

PP

V

CC

V

SS

June 1996 1/13

Address Strobe / Program Supply
Supply Voltage
Ground

ASV

PP

V

SS

AI00928B

M87C257

Figure 2A. DIP Pin Connecti on s

ASV

PP

A12

A7
A6
A5
A4
A3
A2
A1
A0

Q0

Q2
SS

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

M87C257

28
27
26
25
24
23
22
21
20
19
18
17
16
15

AI00929

V

CC

A14
A13
A8
A9
A11
G
A10
E
Q7
Q6
Q5Q1
Q4
Q3V

Figure 2B. LCC Pin Conn ecti ons

PP

CC

A13

DU

32

DU

V

Q3

A14

Q4

25

Q5

A8
A9
A11
NC
G
A10
E
Q7
Q6

AI00930

ASV

A7

A12

1

A6
A5
A4
A3
A2

9

M87C257
A1
A0

NC

Q0

17

Q1

Q2

SS

V

Warning: NC = Not Connected, DU = Dont’t Use.

Tab l e 2. Absolu te Maxi mu m Ratin gs

Symbol Parameter Value Unit

T

A

T

BIAS

T

STG

(2)

V

IO

V

CC

(2)

V

A9

V

PP

Notes: 1. Except for the rating "Operating Temperature Range", stresses above those lis ted in the Table "Absolute Maximum Ratings"

2. Minimum DC voltage on Input or Output is –0.5V with possible undershoot to –2.0V for a period less than 20 ns. Maximum DC

Ambient Operating Temperature –40 to 125 °C
Temperature Under Bias –50 to 125 °C
Storage Temperature –65 to 150 °C
Input or Output Voltages (except A9) –2 to 7 V
Supply Voltage –2 to 7 V
A9 Voltage –2 to 13.5 V
Program Supply Voltage –2 to 14 V

may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other
conditions above those indicated in the Operating sections of this specificat ion is not implied. Exposure to Abs olute Maxi mum
Rating conditions for extended periods may affect device reliability . Refer also to the SGS-THOMS O N SURE Program and other
relevant quality documents.

voltage on Output is V

+0.5V with possible ove rshoot to VCC +2V for a period less than 20ns.

CC

DEVICE OPER ATION

The modes of operation of the M87C257 are listed
in the Operating Modes. A single power supply is
required in the read mode. All inputs are T TL levels
except for V

and 12V on A9 for Elect ronic S igna-

PP

ture.

(1)

Read Mode
The M87C257 has two control functions, both of

which must be logically active in order to obtain
data at the outputs. Chip Enable (

E) is the power
control and should be used for device selection.
Output Enable (

G) is the output control and should

2/13

T ab le 3. Operating Modes

M87C257

Mode E GA9ASV

Read (Latched Address) V
Read (Applied Address) V
Output Disable V
Program V
Verify V
Program Inhibit V
Standby V
Electronic Signature V

Note: X = VIH or VIL, VID = 12V ± 0.5V

IL

IL

IL

Pulse V

IL

IH

IH

IH

IL

V

IL

V

IL

V

IH

IH

V

IL

V

IH

X X X Hi-Z

V

IL

XVILData Out
XVIHData Out
X X Hi-Z
XVPPData In
XVPPData Out
XVPPHi-Z

V

ID

PP

V

IL

T ab le 4. Electron ic Sig natu r e

Identifier A0 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 Hex Data

Manufacturer’s Code V
Device Code V

IL

IH

be used to gate data to the output pins, inde­pendent of device selection. Assuming that the
addresses are stable (

), the address access time (t

V

IL

delay from

E to output (t

the output after delay of t

G, assuming that E has been low and the ad-

of

AS = VIH) or latched (AS =

ELQV

GLQV

dresses have been stable for at least t
The M87C257 reduces the hardware interface in

multiplexed address-data bus systems. The proc­essor multiplexed bus (AD0-AD7) may be tied to
the M87C257’s address and data pins. No sepa­rate address latch is needed because the
M87C257 latches all address inputs when
low.

Standby Mode
The M87C257 has a standby mode which reduces

the active current from 30mA to 100µA (Address
Stable). The M87C257 is placed in the standby
mode by applying a CMOS high signal to the

00100000 20h
10000000 80h

Two Line Output Control
Because EPROMs are usually used in larger mem-

) is equal to the

AVQV

). Data is available at

from the falling edge

AVQV-tGLQV

ory arrays, this product features a 2 line control
function which accommodates the use of multiple
memory connection. The two line control function
allows:

.

a. the lowest possible memory power dissipation,
b. complete assuranc e that output bus cont entio n

will not occur.
For the most efficient use of thes e two control lines,

E should be decoded and used as the primary

AS is

device selecting function, while

G should be made
a common connection to all devices in the array
and connected to the

READ line from the system
control bus. This ensures that all dese lected mem­ory devices are in their low power standby mode
and that the output pins are only active when data
is desired from a particular memory device.

E
input. When in the standby mode, the outputs are
in a high impedance state, independent of the

G

input.

Q0 - Q7

Codes

3/13

M87C257

T ab le 5. AC Measurement Con ditions

High Speed Standard

Input Rise and Fall Times ≤ 10ns ≤ 20ns
Input Pulse Voltages 0 to 3V 0.4V to 2.4V
Input and Output Timing Ref. Voltages 1.5V 0.8V and 2V

Figure 3. AC Test ing Input Outp ut W avefo rm

High Speed

3V

1.5V

0V

Standard

2.4V

0.4V

T ab le 6. Capacitance

Symbol Parameter Test Condition Min Max Unit

C

IN

C

OUT

Note: 1. Sampled only , not 100% tested.

(1)

(TA = 25 °C, f = 1 MHz )

Input Capacitance VIN = 0V 6 pF
Output Capacitance V

2.0V

0.8V

AI01822

Figure 4. AC T est ing Load Circu it

1.3V

1N914

3.3kΩ

DEVICE

UNDER

TEST

CL = 30pF or 100pF

CL = 30pF for High Speed
CL = 100pF for Standard
CL includes JIG capacitance

= 0V 12 pF

OUT

OUT

AI01823

System Consi der atio n s

The power switching characteristics of Advance
CMOS EPROMs require careful decoupling of the
devices. The supply current, I

, has three seg-

CC

ments that are of interest to the system designer:
the standby current level, the active current level,
and transient current peaks that are produced by
the falling and rising edges of

E. The magnitude of
this transient current peaks is dependent on the
capacitive and inductive loading of the device at the
output. The associated transient vo ltage peaks can
be suppressed by complying with the two line

4/13

output control and by properly select ed decoupling
capacitors. It is recommended that a 0.1µF ceramic
capacitor be used on every device between V

CC

and VSS. This should be a high frequency capacitor
of low inherent inductance and should be placed
as close to the device as possible. In addition, a

4.7µF bulk electrolytic capacitor should be used
between V

and VSS for every eight devices. The

CC

bulk capacitor should be located near the power
supply connection point. The purpose of the bulk
capacitor is to overcome the voltage drop caused
by the inductive effects of PCB trac es.

M87C257

T ab le 7. Read Mode DC Characteristic s

(1)

(TA = 0 to 70°C, –40 to 85°C, –40 to 105°C or –40 to 125°C; VCC = 5V ± 5% or 5V ± 10%; VPP = VCC)

Symbol Parameter Test Condition Min Max Unit

Input Leakage Current 0V ≤ VIN ≤ V

LI

Output Leakage Current 0V ≤ V
Supply Current

Supply Current
(Standby) TTL

E = VIH, ASVPP = VIH, Address Switching 10 mA

E = VIH, ASVPP = VIL, Address Stable 1 mA

OUT

E = VIL, G = VIL,

I

= 0mA, f = 5MHz

OUT

≤ V

CC

CC

I
I

I

CC1

I

LO

CC

E ≥ VCC – 0.2V, ASVPP ≥ VCC – 0.2V,

I

CC2

Supply Current (Standby)
CMOS

Address Switching

E ≥ VCC – 0.2V, ASVPP = VSS,

Address Stable

I

PP

V

V

IH

V
V

Notes: 1. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP.

Program Current VPP = V
Input Low Voltage –0.3 0.8 V

IL

(2)

Input High Voltage 2 VCC + 1 V
Output Low Voltage IOL = 2.1mA 0.4 V

OL

Output High Voltage IOH = –1mA VCC – 0.8V V

OH

2. Maximum DC voltage on Output is V

+0.5V .

CC

CC

±10 µA
±10 µA

30 mA

6mA

100 µA
100 µA

T ab le 8A. Read Mode AC Charact eristi cs

(1)

(TA = 0 to 70°C, –40 to 85°C, –40 to 105°C or –40 to 125°C; VCC = 5V ± 5% or 5V ± 10%; VPP = VCC)

M87C257

-60 -70 -80

Symbol Alt Parameter

Test

Condition

-45

(3)

Min Max Min Max Min Max Min Max

Address Valid to

t

AVQV

t

AVASL

t

ASHASLtLL

t

ASLAX

t

ASLGLtLOE

t

ELQV

t

GLQV

t

EHQZ

t

GHQZ

t

AXQX

Notes: 1. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP.

t

ACC

Output Valid
Address Valid to

t

AL

Address Strobe Low
Address Strobe High

to Address Strobe Low
Address Strobe Low to

t

LA

Address Transition
Address Strobe Low to

Output Enable Low
Chip Enable Low to

t

CE

Output Valid
Output Enable Low to

t

OE

Output Valid

(2)

(2)

2. Sampled only, n ot 100% tested.

3. In case of 45ns speed see High Speed AC measurement conditions.

Chip Enable High to

t

DF

Output Hi-Z
Output Enable High to

t

DF

Output Hi-Z
Address Transition to

t

OH

Output Transition

E = VIL, G = V

G = V

IL

E = V

IL

G = V

IL

E = V

IL

E = VIL,

G = V

IL

IL

45 60 70 80 ns

7777ns

35 35 35 35 ns

20 20 20 20 ns

20 20 20 20 ns

45 60 70 80 ns

25 30 35 40 ns

025030030040ns

025030030040ns

0000ns

Unit

5/13