M27C256B 256 Kbit (32Kb × 8) UV EPROM and OTP EPROM Feature summary ■5V ± 10% supply voltage in Read operation ■Access time: 45ns 28 ■Low power consumption: – Active Current 30mA at 5MHz 1 – Standby Current 100µA FDIP28W (F) ■Programming voltage: 12.75V ± 0.25V ■Programming time: 100µs/Word ■Electronic signature 28 – Manufacturer Code: 20h – Device Code: 8Dh 1 ■ECOPACK® packages available PDIP28 (B) PLCC32 (C) May 2006 Rev 2 1/24 www.st.com 1 Obsolete Product(s) - Obsolete Product(s) Contents M27C256B Contents 1 Summary description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 Device operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.1 Read mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2 Standby mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3 Two-line output control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.4 System considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.5 Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.6 PRESTO II programming algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.7 Program inhibit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.8 Program Verify . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.9 Electronic signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.10 Erasure operation (applies for UV EPROM) . . . . . . . . . . . . . . . . . . . . . . . 11 3 Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4 DC and AC parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5 Package mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 6 Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2/24 Obsolete Product(s) - Obsolete Product(s) M27C256B List of tables List of tables Table 1. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Table 2. Operating modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Table 3. Electronic signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Table 4. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Table 5. AC measurement conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Table 6. Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Table 7. Read mode DC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Table 8. Programming mode DC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 9. Read mode AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Table 10. Read mode AC characteristics 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Table 11. Programming mode AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Table 12. FDIP28WB - 28 pin Ceramic Frit-seal DIP, with window (round 0.280"), package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Table 13. PDIP28 - 28 pin Plastic DIP, 600 mils width, package mechanical data . . . . . . . . . . . . . . 20 Table 14. PLCC32 - 32 pin Rectangular Plastic Leaded Chip Carrier, package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Table 15. Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Table 16. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3/24 Obsolete Product(s) - Obsolete Product(s) List of figures M27C256B List of figures Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 2. DIP connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 3. LCC connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 4. Programming flowchart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 5. AC testing input output waveform. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Figure 6. AC testing load circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 7. Read mode AC waveforms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Figure 8. Programming and Verify modes AC waveforms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 9. FDIP28WB - 28 pin Ceramic Frit-seal DIP, with window, package outline. . . . . . . . . . . . . 19 Figure 10. PDIP28 - 28 pin Plastic DIP, 600 mils width, package outline . . . . . . . . . . . . . . . . . . . . . . 20 Figure 11. PLCC32 - 32 pin Rectangular Plastic Leaded Chip Carrier, package outline. . . . . . . . . . . 21 4/24 Obsolete Product(s) - Obsolete Product(s) M27C256B Summary description 1 Summary description The M27C256B is a 256 Kbit EPROM offered in the two ranges UV (ultra violet erase) and OTP (one time programmable). It is ideally suited for microprocessor systems and is organized as 32,768 by 8 bits. The FDIP28W (window ceramic frit-seal 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 programmed only one time and erasure is not required, the M27C256B is offered in PDIP28 and PLCC32 packages. In order to meet environmental requirements, ST offers the M27C256B in ECOPACK® packages. ECOPACK packages are Lead-free. The category of second Level Interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com. Figure 1. Logic diagram V V CC PP 15 8 A0-A14 Q0-Q7 E M27C256B G V SS AI00755B 5/24 Obsolete Product(s) - Obsolete Product(s) Summary description M27C256B Table 1. Signal names A0-A14 Address Inputs Q0-Q7 Data Outputs E Chip Enable G Output Enable V Program Supply PP V Supply Voltage CC V Ground SS NC Not Connected Internally DU Don’t Use Figure 2. DIP connections V 1 28 V PP CC A12 2 27 A14 A7 3 26 A13 A6 4 25 A8 A5 5 24 A9 A4 6 23 A11 A3 7 22 G M27C256B A2 8 21 A10 A1 9 20 E A0 10 19 Q7 Q0 11 18 Q6 Q1 12 17 Q5 Q2 13 16 Q4 V 14 15 Q3 SS AI00756 6/24 Obsolete Product(s) - Obsolete Product(s) M27C256B Summary description Figure 3. LCC connections 1 32 A6 A8 A5 A9 A4 A11 A3 NC A2 9 M27C256B 25 G A1 A10 A0 E NC Q7 Q0 Q6 17 AI00757 7/24 Obsolete Product(s) - Obsolete Product(s) Q1 A7 Q2 A12 V V SS PP DU DU Q3 V CC Q4 A14 Q5 A13 Device operation M27C256B 2 Device operation The operating modes of the M27C256B are listed in the Operating Modes. A single power supply is required in the read mode. All inputs are TTL levels except for V and 12V on A9 PP for Electronic Signature. 2.1 Read mode The M27C256B 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 be used to gate data to the output pins, independent of device selection. Assuming that the addresses are stable, the address access time (t ) is equal to the delay from E to output (t ). Data is AVQV ELQV available at the output after delay of t from the falling edge of G, assuming that E has GLQV been low and the addresses have been stable for at least t -t . AVQV GLQV 2.2 Standby mode The M27C256B has a standby mode which reduces the supply current from 30mA to 100µA. The M27C256B is placed in the standby mode by applying a CMOS high signal to the E input. When in the standby mode, the outputs are in a high impedance state, independent of the G input. 2.3 Two-line output control Because EPROMs are usually used in larger memory arrays, this product features a 2 line control function which accommodates the use of multiple memory connection. The two line control function allows: ●the lowest possible memory power dissipation, ●complete assurance that output bus contention will not occur. For the most efficient use of these two control lines, E should be decoded and used as the primary 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 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. 8/24 Obsolete Product(s) - Obsolete Product(s) M27C256B Device operation 2.4 System considerations The power switching characteristics of Advance CMOS EPROMs require careful decoupling of the devices. The supply current, I , has three segments that are of interest to the system CC 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 voltage peaks can be suppressed by complying with the two line output control and by properly selected decoupling capacitors. It is recommended that a 0.1µF ceramic capacitor be used on every device between V and V . This should be a high CC SS frequency capacitor of low inherent inductance and should be placed as close to the device as possible. In addition, a 4.7µF bulk elec trolytic capacitor should be used between V and CC V for every eight devices. The bulk capacitor should be located near the power supply SS connection point. The purpose of the bulk capacitor is to overcome the voltage drop caused by the inductive effects of PCB traces. 2.5 Programming When delivered (and after each erasure for UV EPROM), all bits of the M27C256B are in the "1" 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 present in the data word. The only way to change a '0' to a '1' is by die exposure to ultraviolet light (UV EPROM). The M27C256B is in the programming mode when V input is at 12.75V, G is at V and E is PP IH pulsed to V . The data to be programmed is applied to 8 bits in parallel to the data output IL pins. The levels required for the address and data inputs are TTL. V is specified to be CC 6.25V ± 0.25 V. 2.6 PRESTO II programming algorithm PRESTO II Programming Algorithm allows to program the whole array with a guaranteed margin, in a typical time of 3.5 seconds. Programming with PRESTO II involves the application of a sequence of 100µs program pulses to each byte until a correct verify occurs (see Figure 4.). During programming and verify operation, a MARGIN MODE circuit is automatically activated in order to guarantee that each cell is programmed with enough margin. No overprogram pulse is applied since the verify in MARGIN MODE provides necessary margin to each programmed cell. 9/24 Obsolete Product(s) - Obsolete Product(s) Device operation M27C256B Figure 4. Programming flowchart V = 6.25V, V = 12.75V CC PP n = 0 E = 100µs Pulse NO NO ++n VERIFY ++ Addr = 25 YES YES Last NO FAIL Addr YES CHECK ALL BYTES 1st: V = 6V CC 2nd: V = 4.2V CC AI00760B 2.7 Program inhibit Programming of multiple M27C256Bs in parallel with different data is also easily accomplished. Except for E, all like inputs including G of the parallel M27C256B may be common. A TTL low level pulse applied to a M27C256B's E input, with V at 12.75V, will PP program that M27C256B. A high level E input inhibits the other M27C256Bs from being programmed. 2.8 Program Verify A verify (read) should be performed on the programmed bits to determine that they were correctly programmed. The verify is accomplished with G at V , E at V , V at 12.75V and IL IH PP V at 6.25V. CC 2.9 Electronic signature The Electronic Signature (ES) mode allows the reading out of a binary code from an EPROM that will identify its manufacturer and type. This mode is intended for use by programming equipment to automatically match the device to be programmed with its corresponding programming algorithm. The ES mode is functional in the 25°C ± 5°C ambient temperature range that is required when programming the M27C256B. To activate the ES mode, the programming equipment must force 11.5V to 12.5V on address line A9 of the M27C256B, with V = V = 5V. Two identifier bytes may then be sequenced from the CC PP device outputs by toggling address line A0 from V to V . All other address lines must be IL IH held at V during Electronic Signature mode. Byte 0 (A0 = V ) represents the manufacturer IL IL code and byte 1 (A0 = V ) the device identifier code. For the STMicroelectronics IH M27C256B, these two identifier bytes are given in Table 3 and can be read-out on outputs Q7 to Q0. 10/24 Obsolete Product(s) - Obsolete Product(s) M27C256B Device operation 2.10 Erasure operation (applies for UV EPROM) The erasure characteristics of the M27C256B is such that erasure begins when the cells are exposed to light with wavelengths shorter than approximately 4000 Å. It should be noted that sunlight and some type of fluorescent lamps have wavelengths in the 3000-4000 Å range. Research shows that constant exposure to room level fluorescent lighting could erase a typical M27C256B in about 3 years, while it would take approximately 1 week to cause erasure when exposed to direct sunlight. If the M27C256B is to be exposed to these types of lighting conditions for extended periods of time, it is suggested that opaque labels be put over the M27C256B window to prevent unintentional erasure. The recommended erasure procedure for the M27C256B is exposure to short wave ultraviolet light which has wavelength 2537Å. The integrated dose (i.e. UV intensity x exposure time) for erasure 2 should be a minimum of 15 W-sec/cm . The erasure time with this dosage is approximately 2 15 to 20 minutes using an ultraviolet lamp with 12000 µW/cm power rating. The M27C256B should be placed within 2.5 cm (1 inch) of the lamp tubes during the erasure. Some lamps have a filter on their tubes which should be removed before erasure. (1) Table 2. Operating modes Mode E G A9 V Q7-Q0 PP Read V V XV Data Out IL IL CC Output Disable V V XV Hi-Z IL IH CC Program V Pulse V XV Data In IL IH PP Verify V V XV Data Out IH IL PP Program Inhibit V V XV Hi-Z IH IH PP Standby V XX V Hi-Z IH CC Electronic Signature V V V V Codes IL IL ID CC 1. X = V or V , V = 12V ± 0.5V. IH IL ID Table 3. Electronic signature Identifier A0 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 Hex Data Manufacturer’s V 00 10 00 00 20h IL Code Device Code V 10 00 11 01 8Dh IH 11/24 Obsolete Product(s) - Obsolete Product(s) Maximum rating M27C256B 3 Maximum rating Stressing the device above the rating listed in the Absolute Maximum Ratings table 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 specification is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Refer also to the STMicroelectronics SURE Program and other relevant quality documents. Table 4. Absolute maximum ratings Symbol Parameter Value Unit (1) T Ambient Operating Temperature –40 to 125 °C A T Temperature Under Bias –50 to 125 °C BIAS T Storage Temperature –65 to 150 °C STG (2) V Input or Output Voltage (except A9) –2 to 7 V IO V Supply Voltage –2 to 7 V CC (2) V A9 Voltage –2 to 13.5 V A9 V Program Supply Voltage –2 to 14 V PP 1. Depends on range. 2. Minimum DC voltage on Input or Output is –0.5V with possible undershoot to –2.0V for a period less than 20ns. Maximum DC voltage on Output is V +0.5V with possible overshoot to V +2V for a period less CC CC than 20ns. 12/24 Obsolete Product(s) - Obsolete Product(s) M27C256B DC and AC parameters 4 DC and AC parameters This section summarizes the operating and measurement conditions, and the DC and AC characteristics of the device. The parameters in the DC and AC Characteristic tables that follow are derived from tests performed under the Measurement Conditions summarized in the relevant tables. Designers should check that the operating conditions in their circuit match the measurement conditions when relying on the quoted parameters. Table 5. AC measurement conditions 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. 1.5V 0.8V and 2V Voltages Figure 5. AC testing input output waveform High Speed 3V 1.5V 0V Standard 2.4V 2.0V 0.8V 0.4V AI01822 13/24 Obsolete Product(s) - Obsolete Product(s) DC and AC parameters M27C256B Figure 6. AC testing load circuit 1.3V 1N914 3.3kΩ DEVICE UNDER OUT TEST C L C = 30pF for High Speed L C = 100pF for Standard L C includes JIG capacitance AI01823B L (1) (2) Table 6. Capacitance Symbol Parameter Test Condition Min Max Unit C Input Capacitance V = 0V 6 pF IN IN C Output Capacitance V = 0V 12 pF OUT OUT 1. Sampled only, not 100% tested. 2. (T = 25 °C, f = 1 MHz) A (1) (2) Table 7. Read mode DC characteristics Symbol Parameter Test Condition Min Max Unit I Input Leakage Current 0V ≤V ≤ V ±10µA LI IN CC I Output Leakage Current 0V ≤ V ≤ V ±10µA LO OUT CC E = V , G = V , IL IL I Supply Current 30 mA CC I = 0mA, f = 5MHz OUT I Supply Current (Standby) TTL E = V 1mA CC1 IH Supply Current (Standby) I E > V – 0.2V 100 µA CC2 CC CMOS I Program Current V = V 100 µA PP PP CC V Input Low Voltage –0.3 0.8 V IL (3) V Input High Voltage 2 V + 1 V IH CC V Output Low Voltage I = 2.1mA 0.4 V OL OL Output High Voltage TTL I = –1mA 3.6 V OH V OH Output High Voltage CMOS I = –100µA V – 0.7V V OH CC 1. T = 0 to 70°C, –40 to 85°C, –40 to 105°C or –40 to 125°C; V = 5V ± 5% or 5V ± 10%; V = V . A CC PP CC 2. V must be applied simultaneously with or before V and removed simultaneously or after V . CC PP PP 3. Maximum DC voltage on Output is V +0.5V. CC 14/24 Obsolete Product(s) - Obsolete Product(s) M27C256B DC and AC parameters (1) (2) Table 8. Programming mode DC characteristics Symbol Parameter Test Condition Min Max Unit I Input Leakage Current V ≤V ≤V ±10µA LI IL IN IH I Supply Current 50 mA CC I Program Current E = V 50 mA PP IL V Input Low Voltage –0.3 0.8 V IL V Input High Voltage 2 V + 0.5 V IH CC V Output Low Voltage I = 2.1mA 0.4 V OL OL V Output High Voltage TTL I = –1mA 3.6 V OH OH V A9 Voltage 11.5 12.5 V ID 1. T = 25 °C; V = 6.25V ± 0.25V; V = 12.75V ± 0.25V. A CC PP 2. V must be applied simultaneously with or before V and removed simultaneously or after V . CC PP PP 15/24 Obsolete Product(s) - Obsolete Product(s) DC and AC parameters M27C256B Figure 7. Read mode AC waveforms VALID VALID A0-A14 tAVQV tAXQX E tEHQZ tGLQV G tGHQZ tELQV Hi-Z Q0-Q7 AI00758B ) (1) (2) Table 9. Read mode AC characteristics M27C256B Test (3) Symbol Alt Parameter -45 -60 -70 -80 Unit Condition Min Max Min Max Min Max Min Max Address Valid to E = V , IL t t 45 60 70 80 ns AVQV ACC Output Valid G = V IL Chip Enable Low t t G = V 45 60 70 80 ns ELQV CE IL to Output Valid Output Enable Low t t E = V 25 30 35 40 ns GLQV OE IL to Output Valid Chip Enable High (4) t t G = V 0 25 0 300300 30 ns EHQZ DF IL to Output Hi-Z Output Enable (4) t t E = V 0 25 0 300300 30 ns GHQZ DF IL High to Output Hi-Z Address Transition E = V , IL t t to Output 0 000ns AXQX OH G = V IL Transition 1. T = 0 to 70°C, –40 to 85°C, –40 to 105°C or –40 to 125°C; V = 5V ± 5% or 5V ± 10%; V = V A CC PP CC 2. V must be applied simultaneously with or before V and removed simultaneously or after V . CC PP PP 3. Speed obtained with High Speed AC measurement conditions. 4. Sampled only, not 100% tested. 16/24 Obsolete Product(s) - Obsolete Product(s) M27C256B DC and AC parameters ) (1) (2) Table 10. Read mode AC characteristics 2 M27C256B Test Symbol Alt Parameter -90 -10 -12 -15/-20/-25 Unit Condition Min Max Min Max Min Max Min Max Address Valid to E = V , IL t t 90 100 120 150 ns AVQV ACC Output Valid G = V IL Chip Enable Low t t G = V 90 100 120 150 ns ELQV CE IL to Output Valid Output Enable t t Low to Output E = V 40 50 60 65 ns GLQV OE IL Valid Chip Enable High (3) t t G = V 0 30 0 30 0 40 0 50 ns EHQZ DF IL to Output Hi-Z Output Enable (3) t t High to Output E = V 0 30 0 30 0 40 0 50 ns GHQZ DF IL Hi-Z Address E = V , IL t t Transition to 00 0 0 ns AXQX OH G = V IL Output Transition 1. T = 0 to 70°C, –40 to 85°C, –40 to 105°C or –40 to 125°C; V = 5V ± 5% or 5V ± 10%; V = V A CC PP CC 2. V must be applied simultaneously with or before V and removed simultaneously or after V . CC PP PP 3. Sampled only, not 100% tested. 17/24 Obsolete Product(s) - Obsolete Product(s) DC and AC parameters M27C256B Figure 8. Programming and Verify modes AC waveforms VALID A0-A14 tAVEL Q0-Q7 DATA IN DATA OUT tQVEL tEHQX V PP tVPHEL tGLQV tGHQZ V CC tVCHEL tGHAX E tELEH tQXGL G PROGRAM VERIFY AI00759 (1) (2) Table 11. Programming mode AC characteristics Test Symbol Alt Parameter Min Max Unit Condition t t Address Valid to Chip Enable Low 2µs AVEL AS t t Input Valid to Chip Enable Low 2µs QVEL DS t t V High to Chip Enable Low 2µs VPHEL VPS PP t t V High to Chip Enable Low 2 µs VCHEL VCS CC t t Chip Enable Program Pulse Width 95 105µs ELEH PW t t Chip Enable High to Input Transition 2µs EHQX DH t t Input Transition to Output Enable Low 2µs QXGL OES t t Output Enable Low to Output Valid 100 ns GLQV OE t t Output Enable High to Output Hi-Z 0 130 ns GHQZ DFP t t Output Enable High to Address Transition 0 ns GHAX AH 1. T = 25 °C; V = 6.25V ± 0.25V; V = 12.75V ± 0.25V. A CC PP 2. V must be applied simultaneously with or before V and removed simultaneously or after V . CC PP PP 18/24 Obsolete Product(s) - Obsolete Product(s) M27C256B Package mechanical 5 Package mechanical Figure 9. FDIP28WB - 28 pin Ceramic Frit-seal DIP, with window, package outline A2 A3 A A1 L α B1 B e C eA D2 eB D S N ∅ E1 E 1 FDIPW-a 1. Drawing is not to scale. Table 12. FDIP28WB - 28 pin Ceramic Frit-seal DIP, with window (round 0.280"), package mechanical data millimeters inches Symbol Typ Min Max Typ Min Max A 5.72 0.225 A1 0.51 1.40 0.020 0.055 A2 3.91 4.57 0.154 0.180 A3 3.89 4.50 0.153 0.177 B 0.41 0.56 0.016 0.022 B1 1.45 – – 0.057 – – C 0.23 0.30 0.009 0.012 D 36.50 37.34 1.437 1.470 D2 33.02 – – 1.300 – – E 15.24 – – 0.600 – – E1 13.06 13.36 0.514 0.526 e2.54– – 0.100 – – eA 14.99 – – 0.590 – – eB 16.18 18.03 0.637 0.710 L 3.18 4.10 0.125 0.161 S 1.52 2.49 0.060 0.098 ∅ 7.11 – – 0.280 – – α 4° 11° 4° 11° N28 28 19/24 Obsolete Product(s) - Obsolete Product(s) Package mechanical M27C256B Figure 10. PDIP28 - 28 pin Plastic DIP, 600 mils width, package outline A2 A A1 L α C B1 B e1 eA D2 eB D S N E1 E 1 PDIP 1. Drawing is not to scale. Table 13. PDIP28 - 28 pin Plastic DIP, 600 mils width, package mechanical data millimeters inches Symbol Typ Min Max Typ Min Max A 4.445 0.1750 A1 0.630 0.0248 A2 3.810 3.050 4.570 0.1500 0.1201 0.1799 B 0.450 0.0177 B1 1.270 0.0500 C 0.230 0.310 0.0091 0.0122 D 36.830 36.580 37.080 1.4500 1.4402 1.4598 D2 33.020 – – 1.3000 – – E 15.240 0.6000 E1 13.720 12.700 14.480 0.5402 0.5000 0.5701 e1 2.540 – – 0.1000 – – eA 15.000 14.800 15.200 0.5906 0.5827 0.5984 eB 15.200 16.680 0.5984 0.6567 L 3.300 0.1299 S 1.78 2.08 0.070 0.082 α 0° 10° 0° 10° N28 28 20/24 Obsolete Product(s) - Obsolete Product(s) M27C256B Package mechanical Figure 11. PLCC32 - 32 pin Rectangular Plastic Leaded Chip Carrier, package outline D A1 D1 A2 1 N B1 E2 e E3 E1 E F B 0.51 (.020) E2 1.14 (.045) D3 A R CP D2 D2 PLCC-A 1. Drawing is not to scale. Table 14. PLCC32 - 32 pin Rectangular Plastic Leaded Chip Carrier, package mechanical data millimeters inches Symbol Typ Min Max Typ Min Max A 3.17 3.56 0.125 0.140 A1 1.53 2.41 0.060 0.095 A2 0.38 – 0.015 – B 0.33 0.53 0.013 0.021 B1 0.66 0.81 0.026 0.032 CP 0.10 0.004 D 12.32 12.57 0.485 0.495 D1 11.35 11.51 0.447 0.453 D2 4.78 5.66 0.188 0.223 D3 7.62 – – 0.300 – – E 14.86 15.11 0.585 0.595 E1 13.89 14.05 0.547 0.553 E2 6.05 6.93 0.238 0.273 E3 10.16– –0.400 – – e1.27– – 0.050 – – F 0.00 0.13 0.000 0.005 R0.89 – – 0.035 – – N32 32 21/24 Obsolete Product(s) - Obsolete Product(s) Part numbering M27C256B 6 Part numbering Table 15. Ordering information scheme Example: M27C256B -70 X C 1 TR Device Type M27 Supply Voltage C = 5V Device Function 256B = 256 Kbit (32Kb x 8) Speed (1) -45 = 45 ns -60 = 60 ns -70 = 70 ns -80 = 80 ns -90 = 90 ns -10 = 100 ns -12 = 120 ns -15 = 150 ns -20 = 200 ns -25 = 250 ns V Tolerance CC blank = ± 10% X = ± 5% Package F = FDIP28W B = PDIP28 C = PLCC32 Temperature Range 1 = 0 to 70 °C 3 = –40 to 125 °C 6 = –40 to 85 °C Options TR = Tape & Reel Packing 1. High Speed, see AC Characteristics section for further information. For a list of available options (Speed, Package, etc) or for further information on any aspect of this device, please contact the STMicroelectronics Sales Office nearest to you. 22/24 Obsolete Product(s) - Obsolete Product(s) M27C256B Revision history 7 Revision history Table 16. Document revision history Date Version Revision Details July 1998 1.0 First Issue 20-Sep-2000 1.1 AN620 Reference removed 29-Nov-2000 1.2 PLCC codification changed (Table 15.) 02-Apr-2001 1.3 FDIP28W mechanical dimensions changed (Table 12.) Package mechanical data clarified for PDIP28 (Table 13.), 29-Aug-2002 1.4 PLCC32 (Table 14., Figure 11.) and TSOP28 (Table 15., Figure 13.) Document converted to new template (sections added, information moved). 18-May-2006 2 TSOP28 package removed. Packages are ECOPACK® compliant. X option removed from Table 15: Ordering information scheme. 23/24 Obsolete Product(s) - Obsolete Product(s) M27C256B Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. 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