FM27C256
262,144-Bit (32K x 8) High Performance CMOS EPROM
FM27C256 262,144-Bit (32K x 8) High Performance CMOS EPROM
General Description
The FM27C256 is a 256K Electrically Programmable Read Only
Memory. It is manufactured in Fairchild’s latest CMOS split gate
EPROM technology which enables it to operate at speeds as fast
as 90 ns access time over the full operating range.
The FM27C256 provides microprocessor-based systems extensive storage capacity for large portions of operating system and
application software. Its 90 ns access time provides high speed
operation with high-performance CPUs. The FM27C256 offers a
single chip solution for the code storage requirements of 100%
firmware-based equipment. Frequently-used software routines
are quickly executed from EPROM storage, greatly enhancing
system utility.
The FM27C256 is configured in the standard EPROM pinout
which provides an easy upgrade path for systems which are
currently using standard EPROMs.
Block Diagram
V
CC
GND
V
PP
OE
CE/PGM
Output Enable
and Chip Enable Logic
The FM27C256 is one member of a high density EPROM Family
which range in densities up to 4 Mb.
Features
■ High performance CMOS
—90, 120, 150 ns access time
Note: Compatible EPROM pin configurations are shown in the blocks adjacent to the FM27C256 pins.
27C51227C512
27C01027C010
XX/V
PP
PP
A
16
A
15
A
12
A
A
A
A
A
A
A
A
O
O
O
GND
7
6
5
4
3
2
1
0
0
1
2
A
15
A
12
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
O
O
O
GND
V
PP
A
12
A
A
A
A
A
A
A
A
O
0
O
1
O
2
GND
FM27C256
1
2
3
7
4
6
5
5
6
4
7
3
8
2
9
1
10
0
11
0
12
1
13
2
14
DlP
28
V
CC
27
A
14
26
A
13
25
A
8
24
A
9
23
A
11
22
OE
21
A
10
20
CE/PGM
19
O
7
18
O
6
17
O
5
16
O
4
15
O
3
V
CC
A
14
A
13
A
8
A
9
A
11
OE/V
PP
A
10
CE/PGM
O
7
O
6
O
5
O
4
O
3
V
CC
XX/PGM
XX
A
14
A
13
A
8
A
9
A
11
OE
A
10
CE
O
7
O
6
O
5
O
4
O
3
V
CC
A
18
A
17
A
14
A
13
A
8
A
9
A
11
OE
A
10
CE/PGM
O
7
O
6
O
5
O
4
O
3
FM27C256 262,144-Bit (32K x 8) High Performance CMOS EPROM
Commercial Temp. Range (0°C to +70°C)
VCC = 5V ±10%
Parameter/Order NumberAccess Time (ns)
FM27C256 Q, V 9090
FM27C256 Q, V 120120
FM27C256 Q, V 150150
Extended Temp. Range (-40°C to +85°C)
VCC = 5V ±10%
Parameter/Order NumberAccess Time (ns)
FM27C256 QE, VE 9090
FM27C256 QE, VE 120120
FM27C256 QE, VE 150150
Package Types: FM27C256 Q, V XXX
Q = Quartz-Windowed Ceramic DIP
V = Surface-Mount PLCC
• All Packages conform to the JEDEC standard.
• All versions are guaranteed to function for slower speeds.
Pin Names
SymbolDescription
A0–A14Addresses
CE/PGMChip Enable/Program
OEOutput Enable
O0–O7Outputs
XXDon’t Care (during Read)
PLCC
VCCA14A
13
29
28
27
26
25
24
23
22
21
A
A
A
A
A
A
A
XX
O
A7A12VPPXX
4 3 2 1 32 31 30
5
6
6
5
7
4
8
3
9
2
10
1
11
0
12
13
0
14 15 16 17 18 19 20
A
8
A
9
A
11
XX
OE
A
10
CE/PGM
O
7
O
6
FM27C256 Rev. A
GND
XX
3O4O5
O
O1O
2
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Page 3
FM27C256 262,144-Bit (32K x 8) High Performance CMOS EPROM
Absolute Maximum Ratings (Note 1)
Storage Temperature-65°C to +150°C
ESD Protection> 2000V
All Output Voltages with
Respect to GroundVCC + 1.0V to GND -0.6V
All Input Voltages except A9 with
Respect to Ground-0.6V to +7V
VPP and A9 with Respect
to Ground-0.7V to +14V
VCC Supply Voltage with
Respect to Ground-0.6V to +7V
Operating Range
RangeTemperatureV
Comm’l0°C to +70°C+5V ±10%
Industrial-40°C to +85°C+5V ±10%
Read Operation
DC Electrical Characteristics Over Operating Range with V
SymbolParameterTest ConditionsMinMaxUnits
V
IL
V
IH
V
OL
V
OH
I
SB1
(Note 11)(CMOS)
I
SB2
I
CC1
I
PP
V
PP
I
LI
I
LO
Input Low Level-0.50.8V
Input High Level2.0VCC +1V
Output Low VoltageIOL = 2.1 mA0.4V
Output High VoltageIOH = -2.5 mA3.5V
VCC Standby CurrentCE = VCC ±0.3V100µA
VCC Standby Current (TTL)CE = V
IH
VCC Active CurrentCE = OE = VIL,f=5 MHz35mA
TTL InputsInputs = VIH or VIL, I/O = 0 mA
VPP Supply CurrentVPP = V
CC
VPP Read VoltageVCC - 0.7V
Input Load CurrentVIN = 5.5V or GND-11µA
Output Leakage CurrentV
= 5.5V or GND-1010µA
OUT
PP
= V
CC
1mA
10µA
CC
CC
V
AC Electrical Characteristics Over Operating Range with V
PP
= V
CC
SymbolParameter90120150Units
MinMaxMinMaxMinMax
t
ACC
t
CE
t
OE
t
DF
(Note 2)Output Float
t
OH
(Note 2)Addresses,
Capacitance (Note 2) T
Address to Output Delay
90120150ns
CE to Output Delay90120150
OE to Output Delay355050
Output Disable to303545
Output Hold from000
CE or OE, Whichever
Occurred First
= +25˚C, f = 1 MHz
A
SymbolParameterConditions Typ Max Units
C
IN
C
OUT
Input CapacitanceVIN = 0V612pF
Output Capacitance V
= 0V912pF
OUT
FM27C256 Rev. A
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Page 4
AC Test Conditions
Output Load1 TTL Gate and CL = 100 pF (Note 8)
Input Rise and Fall Times≤ 5 ns
Input Pulse Levels0.45 to 2.4V
Timing Measurement Reference Level (Note 10)
Inputs0.8V and 2.0V
Outputs0.8V and 2.0V
AC Waveforms (Note 6) (Note 7) (Note 9)
FM27C256 262,144-Bit (32K x 8) High Performance CMOS EPROM
OUTPUT
CE
OE
2.0V
0.8V
2.0V
0.8V
2.0V
0.8V
2.0V
0.8V
ADDRESSES VALID
t
CE
t
OE
(Note 3)
t
ACC
(Note 3)
VALID OUTPUT
t
OH
t
CE
(Notes 4, 5)
t
DF
(Notes 4, 5)
Hi-ZHi-Z
ADDRESSES
Note 1: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is stress rating only and functional operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
Note 2: This parameter is only sampled and is not 100% tested.
Note 3: OE may be delayed up to t
Note 4: The tDF and tCF compare level is determined as follows:
High to TRI-STATE®, the measured V
Low to TRI-STATE, the measured V
- tOE after the falling edge of CE without impacting t
ACC
(DC) - 0.10V;
OH1
(DC) + 0.10V.
OL1
ACC
.
Note 5: TRI-STATE may be attained using OE or CE.
Note 6: The power switching characteristics of EPROMs require careful device decoupling. It is recommended that at least a 0.1 µF ceramic capacitor be used on every device
between VCC and GND.
Note 7: The outputs must be restricted to VCC + 1.0V to avoid latch-up and device damage.
Note 8: TTL Gate: IOL = 1.6 mA, IOH = -400 µA.
CL = 100 pF includes fixture capacitance.
Note 9: VPP may be connected to VCC except during programming.
Note 10: Inputs and outputs can undershoot to -2.0V for 20 ns Max.
Note 11: CMOS inputs: VIL = GND ±0.3V, VIH = VCC ±0.3V.
Address Setup Time1µs
OE Setup Time1µs
VPP Setup Time1µs
VCC Setup Time1µs
Data Setup Time1µs
Address Hold Time0µs
Data Hold Time1µs
Output Enable to OutputCE = V
IL
060ns
Float Delay
Program Pulse Width4550105µs
Data Valid from OECE = V
VPP Supply CurrentCE = V
during Programming Pulse
IL
IL
100ns
30mA
VCC Supply Current50mA
Temperature Ambient202530°C
Power Supply Voltage6.256.56.75V
Programming Supply Voltage12.512.7513.0V
Input Rise, Fall Time5ns
Input Low Voltage0.00.45V
Input High Voltage2.44.0V
Input Timing Reference Voltage0.82.0V
Output Timing Reference Voltage0.82.0V
FM27C256 262,144-Bit (32K x 8) High Performance CMOS EPROM
Programming Waveforms (Note 14)
t
OE
PROGRAM
VERIFY
DATA OUT VALID
ADD N
t
AH
t
DF
PROGRAM
DATA
V
V
CE
OE
2.0V
0.8V
2.0V
0.8V
5.25V
CC
12.75V
PP
2.0V
0.8V
2.0V
0.8V
t
AS
DATA IN STABLE
t
DS
t
VCS
t
VPS
ADD N
t
ADDRESS N
t
DH
t
PW
OES
ADDRESSES
Note 12: Fairchild’s standard product warranty applies to devices programmed to specifications described herein.
Note 13: VCC must be applied simultaneously or before VPP and removed simultaneously or after VPP. The EPROM must not be inserted into or removed from a board with
voltage applied to VPP or VCC.
Note 14: The maximum absolute allowable voltage which may be applied to the VPP pin during programming is 14V. Care must be taken when switching the VPP supply to
prevent any overshoot from exceeding this 14V maximum specification. At least a 0.1 µF capacitor is required across VPP, VCC to GND to suppress spurious voltage transients
which may damage the device.
Note 15: During power up the PGM pin must be brought high (≥ VIH) either coincident with or before power is applied to VPP.
FM27C256 Rev. A
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Page 6
Turbo Programming Algorithm Flow Chart
VCC = 6.5V VPP = 12.75V
n = 0
ADDRESS = FIRST LOCATION
PROGRAM ONE 50µs PULSE
INCREMENT n
NO
FM27C256 262,144-Bit (32K x 8) High Performance CMOS EPROM
DEVICE
FAILED
YES
n = 10?
INCREMENT
ADDRESS
FAIL
VERIFY
BYTE
PASS
LAST
ADDRESS
NO
?
YES
ADDRESS = FIRST LOCATION
VERIFY
FAIL
BYTE
PASS
LAST
NO
ADDRESS
?
YES
INCREMENT
ADDRESS
n = 0
PROGRAM ONE
50 µs
PULSE
CHECK ALL BYTES
= VPP = 6.0V
1ST: V
CC
2ND: V
Note: The standard National Semiconductor algorithm may also be used but it will have longer programming time.
= VPP = 4.3V
CC
FIGURE 1.
6
FM27C256 Rev. A
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Page 7
FM27C256 262,144-Bit (32K x 8) High Performance CMOS EPROM
Functional Description
DEVICE OPERATION
The six modes of operation of the EPROM are listed in Table 1. It
should be noted that all inputs for the six modes are at TTL levels.
The power supplies required are V
supply must be at 12.75V during the three programming modes,
and must be at 5V in the other three modes. The V
must be at 6.5V during the three programming modes, and at 5V
in the other three modes.
Read Mode
The EPROM has two control functions, both of which must be
logically active in order to obtain data at the outputs. Chip Enable
(CE/PGM) 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 (t
available at the outputs t
that CE/PGM has been low and addresses have been stable for
at least t
) is equal to the delay from CE to output (tCE). Data is
ACC
ACC
–tOE.
after the falling edge of OE, assuming
OE
Standby Mode
The EPROM has a standby mode which reduces the active power
dissipation by over 99%, from 385 mW to 0.55 mW. The EPROM
is placed in the standby mode by applying a CMOS high signal to
the CE/PGM input. When in standby mode, the outputs are in a
high impedance state, independent of the OE input.
Output Disable
The EPROM is placed in output disable by applying a TTL high
signal to the OE input. When in output disable all circuitry is
enabled, except the outputs are in a high impedance state (TRISTATE).
Output OR-Typing
Because the EPROM is usually used in larger memory arrays,
Fairchild has provided a 2-line control function that accommodates this use of multiple memory connections. The 2-line control
function allows for:
1. the lowest possible memory power dissipation, and
2. complete assurance that output bus contention will not
occur.
To most efficiently use these two control lines, it is recommended
that CE/PGM 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 modes and that the output
pins are active only when data is desired from a particular memory
device.
Programming
CAUTION: Exceeding 14V on pin 1 (VPP) will damage the EPROM.
Initially, and after each erasure, all bits of the EPROM are in the
“1’s” state. Data is introduced by selectively programming “0’s”
into the desired bit locations. Although only “0’s” will be programmed, both “1’s” and “0’s” can be presented in the data word.
The only way to change a “0” to a “1” is by ultraviolet light erasure.
and VPP. The VPP power
CC
power supply
CC
The EPROM is in the programming mode when the VPP power
supply is at 12.75V and OE is at V
0.1 µF capacitor be placed across V
spurious voltage transients which may damage the device. The
data to be programmed is applied 8 bits in parallel to the data
output pins. The levels required for the address and data inputs
are TTL.
When the address and data are stable, an active low, TTL program
pulse is applied to the CE/PGM input. A program pulse must be
applied at each address location to be programmed. The EPROM
is programmed with the Turbo Programming Algorithm shown in
Figure 1. Each Address is programmed with a series of 50 µs
pulses until it verifies good, up to a maximum of 10 pulses. Most
memory cells will program with a single 50 µs pulse. (The standard
National Semiconductor Algorithm may also be used but it will
have longer programming time.)
The EPROM must not be programmed with a DC signal applied to
the CE/PGM input.
Programming multiple EPROM in parallel with the same data can
be easily accomplished due to the simplicity of the programming
requirments. Like inputs of the parallel EPROM may be connected
together when they are programmed with the same data. A low
level TTL pulse applied to the CE/PGM input programs the
paralleled EPROM.
. It is required that at least a
IH
, VCC to ground to suppress
PP
Program Inhibit
Programming multiple EPROMs in parallel with different data is
also easily accomplished. Except for CE/PGM, all like inputs
(including OE) of the parallel EPROMs may be common. A TTL
low level program pulse applied to an EPROM’s CE/PGM input
with VPP at 12.75V will program that EPROM. A TTL high level CE/
PGM input inhibits the other EPROMs from being programmed.
Program Verify
A verify should be performed on the programmed bits to determine
whether they were correctly programmed. The verify may be
performed with VPP at 12.75V. VPP must be at VCC, except during
programming and program verify.
AFTER PROGRAMMING
Opaque labels should be placed over the EPROM window to
prevent unintentional erasure. Covering the window will also
prevent temporary functional failure due to the generation of photo
currents.
MANUFACTURER’S IDENTIFICATION CODE
The EPROM has a manufacturer’s identification code to aid in
programming. When the device is inserted in an EPROM programmer socket, the programmer reads the code and then
automatically calls up the specific programming algorithm for the
part. This automatic programming control is only possible with
programmers which have the capability of reading the code.
The Manufacturer’s Identification code, shown in Table 2, specifically identifies the manufacturer and device type. The code for
FM27C256 is “8F04”, where “8F” designates that it is made by
Fairchild Semiconductor, and “04” designates a 256K part.
The code is accessed by applying 12V ±0.5V to address pin A9.
Addresses A1–A8, A10–A16, and all control pins are held at VIL.
Address pin A0 is held at VIL for the manufacturer’s code, and held
at VIH for the device code. The code is read on the eight data pins,
O0 –O7. Proper code access is only guaranteed at 25°C to ±5°C.
FM27C256 Rev. A
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Page 8
FM27C256 262,144-Bit (32K x 8) High Performance CMOS EPROM
Functional Description (Continued)
ERASURE CHARACTERISTICS
The erasure characteristics of the device are such that erasure
begins to occur when exposed to light with wavelengths shorter
than approximately 4000 Angstroms (Å). It should be noted that
sunlight and certain types of fluorescent lamps have wavelengths
in the 3000Å–4000Å range.
The recommended erasure procedure for the EPROM is exposure to short wave ultraviolet light which has a wavelength of
2537Å. The integrated dose (i.e., UV intensity x exposure time) for
erasure should be a minimum of 15W-sec/cm2.
The EPROM should be placed within 1 inch of the lamp tubes
during erasure. Some lamps have a filter on their tubes which
should be removed before erasure
An erasure system should be calibrated periodically. The distance
from lamp to device should be maintained at one inch. The erasure
time increases as the square of the distance from the lamp (if
distance is doubled the erasure time increases by factor of 4).
Lamps lose intensity as they age. When a lamp is changed, the
distance has changed, or the lamp has aged, the system should
be checked to make certain full erasure is occurring. Incomplete
erasure will cause symptoms that can be misleading. Programmers, components, and even system designs have been erroneously suspected when incomplete erasure was the problem.
SYSTEM CONSIDERATION
The power switching characteristics of EPROMs require careful
decoupling of the devices. The supply current, I
segments that are of interest to the system designer: the standby
current level, the active current level, and the transient current
peaks that are produced by voltage transitions on input pins. The
magnitude of these transient current peaks is dependent of the
output capacitance loading of the device. The associated V
transient voltage peaks can be suppressed by properly selected
decoupling capacitors. It is recommended that at least a 0.1 µF
ceramic capacitor be used on every device between V
GND. This should be a high frequency capacitor of low inherent
inductance. In addition, at least a 4.7 µF bulk electrolytic capacitor
should be used between VCC and GND for each eight devices. The
bulk capacitor should be located near where the power supply is
connected to the array. The purpose of the bulk capacitor is to
overcome the voltage drop caused by the inductive effects of the
PC board traces.
has three
CC,
CC
and
CC
Mode Selection
The modes of operation of FM27C256 listed in Table 1. A single 5V power supply is required in the read mode. All inputs are TTL levels
except for VPP and A9 for device signature.
FM27C256 262,144-Bit (32K x 8) High Performance CMOS EPROM
S
S
Max
0.0100
[0.254]
0.118-0.129
[3.00-3.28]
0.010[0.25]
0.026-0.032
[0.66-0.81]
0.007[0.18]
B A
D-E, F-G
B
H
D-E, F-G
45
°X
B
S
0.042-0.048
[1.07-1.22]
S
Min
0.006-0.012
[0.15-0.30]
0.019-0.025
[0.48-0.64]
0.025
[0.64]
L
Typ
S
0.025
[0.64]
0.021-0.027
[0.53-0.69]
0.027-0.033
[0.69-0.84]
Section B-B
Typical
Min
0.031-0.037
[0.79-0.94]
0.065-0.071
[1.65-1.80]
0.053-0.059
[1.65-1.80]
0.045
[1.14]
Detail A
Typical
Rotated 90°
0.030-0.040
R
[0.76-1.02]
32-Lead Plastic Leaded Chip Carrier (PLCC)
Order Number FM27C256VXXX
Package Number VA32A
Life Support Policy
Fairchild's products are not authorized for use as critical components in life support devices or systems without the express written
approval of the President of Fairchild Semiconductor Corporation. As used herein:
1. Life support devices or systems are devices or systems which,
(a) are intended for surgical implant into the body, or (b) support
or sustain life, and whose failure to perform, when properly
used in accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a significant
injury to the user.
2. A critical component is any component of a life support device
or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system,
or to affect its safety or effectiveness.
Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications.
EnglishTel: +44 (0) 1793-856856Kowloon. Hong KongTokyo, 113-0034 Japan
Français Tel: +33 (0) 1-6930-3696Tel; +852-2722-8338Tel: 81-3-3818-8840
ItalianoTel: +39 (0) 2-249111-1Fax: +852-2722-8383Fax: 81-3-3818-8841
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FM27C256 Rev. A
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