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FINAL
AM27C256
256 Kilobit (32 K x 8-Bit) CMOS EPROM
DISTINCTIVE CHARACTERISTICS
s Fast access time -- Speed options as fast as 45 ns s Low power consumption -- 20 A typical CMOS standby current s JEDEC-approved pinout s Single +5 V power supply s 10% power supply tolerance standard s 100% FlashriteTM programming -- Typical programming time of 4 seconds s Latch-up protected to 100 mA from -1 V to VCC + 1 V s High noise immunity s Versatile features for simple interfacing -- Both CMOS and TTL input/output compatibility -- Two line control functions s Standard 28-pin DIP, PDIP, and 32-pin PLCC packages
GENERAL DESCRIPTION
The AM27C256 is a 256-Kbit, ultraviolet erasable programmable read-only memory. It is organized as 32K words by 8 bits per word, operates from a single +5 V supply, has a static standby mode, and features fast single address location programming. Products are available in windowed ceramic DIP packages, as well as plastic one time programmable (OTP) PDIP and PLCC packages. Data can be typically accessed in less than 55 ns, allowing high-performance microprocessors to operate without any WAIT states. The device offers separate Output Enable (OE#) and Chip Enable (CE#) controls, thus eliminating bus contention in a multiple bus microprocessor system. AMD's CMOS process technology provides high speed, low power, and high noise immunity. Typical power consumption is only 80 mW in active mode, and 100 W in standby mode. All signals are TTL levels, including programming signals. Bit locations may be programmed singly, in blocks, or at random. The device supports AMD's Flashrite programming algorithm (100 s pulses), resulting in a typical programming time of 4 seconds.
BLOCK DIAGRAM
VCC VSS VPP OE# CE# Output Enable Chip Enable and Prog Logic Y Decoder A0-A14 Address Inputs Output Buffers Data Outputs DQ0-DQ7
Y Gating
X Decoder
262,144 Bit Cell Matrix
08007I-1
Publication# 08007 Rev: I Issue Date: May 1998 Amendment/0
PRODUCT SELECTOR GUIDE
Family Part Number Speed Options VCC = 5.0 V 5% VCC = 5.0 V 10% -45 45 45 30 -55 55 55 35 -70 70 70 40 -90 90 90 40 -120 120 120 50 -150 150 150 50 -200 200 200 50 250 250 50 AM27C256 -255
Max Access Time (ns) CE# (E#) Access (ns) OE# (G#) Access (ns)
CONNECTION DIAGRAMS Top View
DIP
A7 A12
PLCC
VCC A14 A13 VPP DU
VPP A12 A7 A6 A5 A4 A3 A2 A1 A0 DQ0 DQ1 DQ2 VSS
1 2 3 4 5 6 7 8 9 10 11 12 13 14
28 27 26 25 24 23 22 21 20 19 18 17 16 15
VCC A14 A13 A8 A9 A11 OE# (G#) A10 CE# (E#) DQ7 DQ6 DQ5 DQ4 DQ3
08007I-2
4 3 2 1 32 31 30 A6 A5 A4 A3 A2 A1 A0 NC DQ0 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 VSS DU DQ3 DQ4 DQ1 DQ2 DQ5 29 28 27 26 25 24 23 22 21 A8 A9 A11 NC OE# (G#) A10 CE# (E#) DQ7 DQ6
08007I-3
Notes: 1. JEDEC nomenclature is in parenthesis. 2. Don't use (DU) for PLCC.
PIN DESIGNATIONS
A0-A14 CE# (E#) DQ0-DQ7 OE# (G#) VCC VPP VSS NC = Address Inputs = Chip Enable Input = Data Input/Outputs = Output Enable Input = VCC Supply Voltage = Program Voltage Input = Ground = No Internal Connection
LOGIC SYMBOL
15 A0-A14 DQ0-DQ7 CE# (E#) 8
OE# (G#)
08007I-4
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AM27C256
ORDERING INFORMATION UV EPROM Products
AMD standard products are available in several packages and operating ranges. The order number (Valid Combination) is formed by a combination of the following:
AM27C256
-45
D
C
B
OPTIONAL PROCESSING Blank = Standard Processing B = Burn-In TEMPERATURE RANGE C = Commercial (0C to +70C) I = Industrial (-40C to +85C) E = Extended (-55C to +125C) PACKAGE TYPE D = 28-Pin Ceramic DIP (CDV028) SPEED OPTION See Product Selector Guide and Valid Combinations
DEVICE NUMBER/DESCRIPTION AM27C256 256 Kilobit (32 K x 8-Bit) CMOS UV EPROM
Valid Combinations AM27C256-45 DC, DCB, DI, DIB AM27C256-55 AM27C256-70 AM27C256-90 AM27C256-120 AM27C256-150 AM27C256-200 AM27C256-255 VCC = 5.0 V 5% DC, DCB, DI, DIB DC, DCB, DI, DIB, DE, DEB
Valid Combinations Valid Combinations list configurations planned to be supported in volume for this device. Consult the local AMD sales office to confirm availability of specific valid combinations and to check on newly released combinations.
AM27C256
3
ORDERING INFORMATION OTP EPROM Products
AMD standard products are available in several packages and operating ranges. The order number (Valid Combination) is formed by a combination of the following:
AM27C256
-55
P
C
OPTIONAL PROCESSING Blank = Standard Processing TEMPERATURE RANGE C = Commercial (0C to +70C) I = Industrial (-40C to +85C) PACKAGE TYPE P = 28-Pin Plastic DIP (PD 028) J = 32-Pin Square Plastic Leaded Chip Carrier (PL 032) SPEED OPTION See Product Selector Guide and Valid Combinations
DEVICE NUMBER/DESCRIPTION AM27C256 256 Kilobit (32 K x 8-Bit) CMOS OTP EPROM
Valid Combinations AM27C256-55 AM27C256-70 AM27C256-90 AM27C256-120 JC, PC, JI, PI AM27C256-150 AM27C256-200 AM27C256-255 JC, PC
Valid Combinations Valid Combinations list configurations planned to be supported in volume for this device. Consult the local AMD sales office to confirm availability of specific valid combinations and to check on newly released combinations.
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AM27C256
FUNCTIONAL DESCRIPTION Device Erasure
In order to clear all locations of their programmed contents, the device must be exposed to an ultraviolet light source. A dosage of 15 W seconds/cm2 is required to completely erase the device. This dosage can be obtained by exposure to an ultraviolet lamp--wavelength of 2537 A--with intensity of 12,000 W/cm2 for 15 to 20 minutes. The device should be directly under and about one inch from the source, and all filters should be removed from the UV light source prior to erasure. Note that all UV erasable devices will erase with light sources having wavelengths shorter than 4000 A, such as fluorescent light and sunlight. Although the erasure process happens over a much longer time period, exposure to any light source should be prevented for maximum system reliability. Simply cover the package window with an opaque label or substance.
VPP = 12.75 V 0.25 V and OE# HIGH will program that particular device. A high-level CE# input inhibits the other devices from being programmed.
Program Verify
A verification should be performed on the programmed bits to determine that they were correctly programmed. The verify should be performed with OE# at VIL, CE# at VIH, and VPP between 12.5 V and 13.0 V.
Autoselect Mode
The autoselect mode provides manufacturer and device identification through identifier codes on DQ0- DQ7. This mode is primarily intended for programming equipment to automatically match a device to be programmed with its corresponding programming algorithm. This mode is functional in the 25C 5C ambient temperature range that is required when programming the device. To activate this mode, the programming equipment must force VH on address line A9. Two identifier bytes may then be sequenced from the device outputs by toggling address line A0 from VIL to VIH (that is, changing the address from 00h to 01h). All other address lines must be held at VIL during the autoselect mode. Byte 0 (A0 = VIL) represents the manufacturer code, and Byte 1 (A0 = VIH), the device identifier code. Both codes have odd parity, with DQ7 as the parity bit.
Device Programming
Upon delivery, or after each erasure, the device has all of its bits in the "ONE", or HIGH state. "ZEROs" are loaded into the device through the programming procedure. The device enters the programming mode when 12.75 V 0.25 V is applied to the VPP pin, OE# is at VIH and CE# is at VIL. For programming, the data to be programmed is applied 8 bits in parallel to the data pins. The flowchar t in the Programming section of the EPROM Products Data Book (Section 5, Figure 5-1) shows AMD's Flashrite algorithm. The Flashrite algorithm reduces programming time by using a 100 s programming pulse and by giving each address only as many pulses to reliably program the data. After each pulse is applied to a given address, the data in that address is verified. If the data does not verify, additional pulses are given until it verifies or the maximum pulses allowed is reached. This process is repeated while sequencing through each address of the device. This part of the algorithm is done at VCC = 6.25 V to assure that each EPROM bit is programmed to a sufficiently high threshold voltage. After the final address is completed, the entire EPROM memory is verified at VCC = VPP = 5.25 V. Please refer to Section 5 of the EPROM Products Data Book for additional programming information and specifications.
Read Mode
To obtain data at the device outputs, Chip Enable (CE#) and Output Enable (OE#) must be driven low. CE# controls the power to the device and is typically used to select the device. OE# enables the device to output data, independent of device selection. Addresses must be stable for at least tACC -tOE. Refer to the Switching Waveforms section for the timing diagram.
Standby Mode
The device enters the CMOS standby mode when CE# is at VCC 0.3 V. Maximum VCC current is reduced to 100 A. The device enters the TTL-standby mode when CE# is at VIH. Maximum VCC current is reduced to 1.0 mA. When in either standby mode, the device places its outputs in a high-impedance state, independent of the OE# input.
Output OR-Tieing
To accommodate multiple memory connections, a two-line control function provides: s Low memory power dissipation, and s Assurance that output bus contention will not occur. CE# should be decoded and used as the primary device-selecting function, while OE# be made a common
Program Inhibit
Programming different data to multiple devices in parallel is easily accomplished. Except for CE#, all like inputs of the devices may be common. A TTL low-level program pulse applied to one device's CE# input with
AM27C256
5
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 memory device.
System Applications
During the switch between active and standby conditions, transient current peaks are produced on the rising and falling edges of Chip Enable. The magnitude of
these transient current peaks is dependent on the output capacitance loading of the device. At a minimum, a 0.1 F ceramic capacitor (high frequency, low inherent inductance) should be used on each device between VCC and VSS 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 F bulk electrolytic capacitor should be used between VCC and VSS for each eight devices. The location of the capacitor should be close to where the power supply is connected to the array.
MODE SELECT TABLE
Mode Read Output Disable Standby (TTL) Standby (CMOS) Program Program Verify Program Inhibit Autoselect (Note 3) Manufacturer Code Device Code CE# VIL X VIH VCC 0.3 V VIL VIL VIH VIL VIL OE# VIL VIH X X X VIL VIH VIL VIL A0 X X X X X X X VIL VIH A9 X X X X X X X VH VH VPP X X X X VPP VPP VPP X X Outputs DOUT High Z High Z High Z DIN DOUT High Z 01h 10h
Notes: 1. VH = 12.0 V 0.5 V. 2. X = Either VIH or VIL. 3. A1-A8 and A10-14 = VIL 4. See DC Programming Characteristics for VPP voltage during programming.
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AM27C256
ABSOLUTE MAXIMUM RATINGS
Storage Temperature OTP Products. . . . . . . . . . . . . . . . . . -65C to +125C All Other Products . . . . . . . . . . . . . . -65C to +150C Ambient Temperature with Power Applied. . . . . . . . . . . . . . -55C to +125C Voltage with Respect to VSS All pins except A9, VPP, VCC . . -0.6 V to VCC + 0.6 V A9 and VPP (Note 2) . . . . . . . . . . . . . -0.6 V to 13.5 V VCC (Note 1). . . . . . . . . . . . . . . . . . . . . -0.6 V to 7.0 V
OPERATING RANGES
Commercial (C) Devices Ambient Temperature (TA) . . . . . . . . . . .0C to +70C Industrial (I) Devices Ambient Temperature (TA) . . . . . . . . .-40C to +85C Extended (E) Devices Ambient Temperature (TA) . . . . . . . .-55C to +125C Supply Read Voltages VCC for 5% devices . . . . . . . . . . +4.75 V to +5.25 V VCC for 10% devices . . . . . . . . . +4.50 V to +5.50 V
Operating ranges define those limits between which the functionality of the device is guaranteed.
Notes:
1. Minimum DC voltage on input or I/O pins -0.5 V. During voltage transitions, the input may overshoot VSS to -2.0 V for periods of up to 20 ns. Maximum DC voltage on input and I/O pins is VCC + 5 V. During voltage transitions, input and I/O pins may overshoot to VCC + 2.0 V for periods up to 20 ns. 2. Minimum DC input voltage on A9 is -0.5 V. During voltage transitions, A9 and VPP may overshoot VSS to -2.0 V for periods of up to 20 ns. A9 and VPP must not exceed +13.5 V at any time. Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only; 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 of the device to absolute maximum ratings for extended periods may affect device reliability.
AM27C256
7
DC CHARACTERISTICS over operating range (unless otherwise specified)
Parameter Symbol VOH VOL VIH VIL ILI ILO ICC1 ICC2 ICC3 IPP1 Parameter Description Output HIGH Voltage Output LOW Voltage Input HIGH Voltage Input LOW Voltage Input Load Current Output Leakage Current VCC Active Current (Note 2) VCC TTL Standby Current VCC CMOS Standby Current VPP Supply Current (Read) VIN = 0 V to VCC C/I Devices VOUT = 0 V to VCC CE# = VIL, f = 10 MHz, IOUT = 0 mA CE# = VIH CE# = VCC 0.3 V CE# = OE# = VIL, VPP = VCC E Devices Test Conditions IOH = -400 A IOL = 2.1 mA 2.0 -0.5 Min 2.4 0.45 VCC + 0.5 +0.8 1.0 1.0 A 5.0 25 1.0 100 100 mA mA A A Max Unit V V V V A
Caution: The device must not be removed from (or inserted into) a socket when VCC or VPP is applied. Notes: 1. VCC must be applied simultaneously or before VPP, and removed simultaneously or after VPP.. 2. ICC1 is tested with OE# = VIH to simulate open outputs. 3. Minimum DC Input Voltage is -0.5 V. During transitions, the inputs may overshoot to -2.0 V for periods less than 20 ns. Maximum DC Voltage on output pins is VCC + 0.5 V, which may overshoot to VCC + 2.0 V for periods less than 20 ns.
30 25 20 15 10 1 2 3 4 5 6 7 Frequency in MHz 8 9 10
30 25 20 15 10 -75 -50 -55
Supply Current in mA
Supply Current in mA
0 25 50 75 100 125 150 Temperature in C
08007I-6
08007I-5
Figure 1.
Typical Supply Current vs. Frequency VCC = 5.5 V, T = 25C
Figure 2. Typical Supply Current vs. Temperature VCC = 5.5 V, f = 10 MHz
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AM27C256
TEST CONDITIONS
5.0 V
Table 1.
Test Condition Output Load
Test Specifications
-45, -55 and -70 All others Unit
Device Under Test CL 6.2 k
2.7 k
1 TTL gate 30 20 0.0-3.0 1.5 1.5 0.45-2.4 0.8, 2.0 0.8, 2.0 100 pF ns V V V
Output Load Capacitance, CL (including jig capacitance) Input Rise and Fall Times Input Pulse Levels
Note: Diodes are IN3064 or equivalents.
08007I-7
Input timing measurement reference levels Output timing measurement reference levels
Figure 3.
Test Setup
SWITCHING TEST WAVEFORM
3V 1.5 V 0V Input Output Test Points 1.5 V 0.8 V 0.45 V Input Output 2.4 V 2.0 V Test Points 0.8 V 2.0 V
Note: For CL = 30 pF.
Note: For CL = 100 pF.
08007I-8
KEY TO SWITCHING WAVEFORMS
WAVEFORM INPUTS Steady Changing from H to L Changing from L to H Don't Care, Any Change Permitted Does Not Apply Changing, State Unknown Center Line is High Impedance State (High Z) OUTPUTS
KS000010-PAL
AM27C256
9
AC CHARACTERISTICS
Parameter Symbols JEDEC tAVQV tELQV tGLQV tEHQZ tGHQZ Standard tACC tCE tOE tDF (Note 2) Description Address to Output Delay Chip Enable to Output Delay Output Enable to Output Delay Chip Enable High or Output Enable High to Output High Z, Whichever Occurs First Output Hold Time from Addresses, CE# or OE#, Whichever Occurs First Test Setup CE#, Max OE# = VIL OE# = VIL Max CE# = VIL Max -45 45 45 30 -55 55 55 35 -70 70 70 40 AM27C256 -90 90 90 40 -120 -150 -200 -255 Unit 120 120 50 150 150 50 200 200 50 250 250 50 ns ns ns
Max
25
25
25
25
30
30
30
30
ns
tAXQX
tOH
Min
0
0
0
0
0
0
0
0
ns
Caution: Do not remove the device from (or insert it into) a socket or board that has VPP or VCC applied.
Notes:
1. VCC must be applied simultaneously or before VPP, and removed simultaneously or after VPP. 2. This parameter is sampled and not 100% tested. 3. Switching characteristics are over operating range, unless otherwise specified. 4. See Figure 3 and Table 1 for test specifications.
SWITCHING WAVEFORMS
2.4 Addresses 0.45 CE# tCE OE# tOE High Z tACC (Note 1) tOH Valid Output High Z
08007I-9
2.0 0.8
Addresses Valid
2.0 0.8
tDF (Note 2)
Output
Notes: 1. OE# may be delayed up to tACC - tOE after the falling edge of the addresses without impact on tACC. 2. tDF is specified from OE# or `CE#, whichever occurs first.
PACKAGE CAPACITANCE
Parameter Description Input Capacitance Output Capacitance CDV028 Test Conditions VIN = 0 VOUT = 0 Typ 8 8 Max 12 12 PL 032 Typ 8 8 Max 12 12 PD 028 Typ 6 8 Max 10 10 Unit pF pF
Parameter Symbol CIN COUT
Notes: 1. This parameter is only sampled and not 100% tested. 2. TA = +25C, f = 1 MHz.
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AM27C256
PHYSICAL DIMENSIONS* CDV028--28-Pin Ceramic Dual In-Line Package, UV Lens (measured in inches)
DATUM D CENTER PLANE
1
UV Lens .565 .605
INDEX AND TERMINAL NO. 1 I.D. AREA
TOP VIEW DATUM D CENTER PLANE 1.435 1.490 BASE PLANE SEATING PLANE .160 .220 .015 .060 .125 .200 .300 BSC .045 .065 .014 .026 .600 BSC .100 BSC .008 .018 .700 MAX
94 105
.005 MIN
SIDE VIEW
END VIEW
16-000038H-3 CDV028 DF10 3-30-95 ae
* For reference only. BSC is an ANSI standard for Basic Space Centering.
PD 028--28-Pin Plastic Dual In-Line Package (measured in inches)
1.440 1.480 28 15 .530 .580 14 .045 .065 .140 .225 .005 MIN 0 10 .630 .700 .008 .015 .600 .625
Pin 1 I.D.
SEATING PLANE .120 .160 .090 .110 .014 .022 .015 .060
16-038-SB-AG PD 028 DG75 7-13-95 ae
AM27C256
11
PHYSICAL DIMENSIONS PL 032--32-Pin Plastic Leaded Chip Carrier (measured in inches)
.447 .453 .485 .495 .009 .015 .125 .140 .080 .095 SEATING PLANE .400 REF. .013 .021 .026 .032 TOP VIEW .050 REF. .490 .530 .042 .056
.585 .595 .547 .553
Pin 1 I.D.
SIDE VIEW
16-038FPO-5 PL 032 DA79 6-28-94 ae
l
REVISION SUMMARY FOR AM27C256 Revision I
Global Changed formatting to match current data sheets. Distinctive Characteristics
Ordering Information
UV EPROM Products: Added the AM27C256-45 Valid Combination.
Test Conditions
Fast access time: Changed "Speed options as fast as 55 ns" to "Speed options as fast as 45 ns".
Product Selector Guide Added the -45 speed option.
Table 1. Test Specifications: Added the -45 speed option.
AC Characteristics Added the -45 speed option.
Trademarks Copyright (c) 1998 Advanced Micro Devices, Inc. All rights reserved. AMD, the AMD logo, and combinations thereof are trademarks of Advanced Micro Devices, Inc. Flashrite is a trademark of Advanced Micro Devices, Inc. Product names used in this publication are for identification purposes only and may be trademarks of their respective companies.
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AM27C256

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