M27C256B 256 Kbit (32Kb × 8) UV EPROM and OTP EPROM Feature summary ■ 5V ± 10% supply voltage in Read operation ■ Access time: 45ns ■ Low power consumption: – Active Current 30mA at 5MHz – Standby Current 100µA ■ Programming voltage: 12.75V ± 0.25V ■ Programming time: 100µs/Word ■ Electronic signature – Manufacturer Code: 20h – Device Code: 8Dh 28 1 FDIP28W (F) 28 1 ■ ECOPACK® packages available PDIP28 (B) PLCC32 (C) May 2006 Rev 2 1/24 www.st.com 1 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 M27C256B List of tables List of tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Table 10. Table 11. Table 12. Table 13. Table 14. Table 15. Table 16. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Operating modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Electronic signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 AC measurement conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Read mode DC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Programming mode DC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Read mode AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Read mode AC characteristics 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Programming mode AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 FDIP28WB - 28 pin Ceramic Frit-seal DIP, with window (round 0.280"), package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 PDIP28 - 28 pin Plastic DIP, 600 mils width, package mechanical data . . . . . . . . . . . . . . 20 PLCC32 - 32 pin Rectangular Plastic Leaded Chip Carrier, package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3/24 List of figures M27C256B List of figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. 4/24 Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 DIP connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 LCC connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Programming flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 AC testing input output waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 AC testing load circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Read mode AC waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Programming and Verify modes AC waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 FDIP28WB - 28 pin Ceramic Frit-seal DIP, with window, package outline . . . . . . . . . . . . . 19 PDIP28 - 28 pin Plastic DIP, 600 mils width, package outline . . . . . . . . . . . . . . . . . . . . . . 20 PLCC32 - 32 pin Rectangular Plastic Leaded Chip Carrier, package outline. . . . . . . . . . . 21 M27C256B 1 Summary description 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 VCC VPP 15 8 A0-A14 E Q0-Q7 M27C256B G VSS AI00755B 5/24 Summary description Table 1. M27C256B Signal names A0-A14 Address Inputs Q0-Q7 Data Outputs E Chip Enable G Output Enable VPP Program Supply VCC Supply Voltage VSS Ground NC Not Connected Internally DU Don’t Use Figure 2. DIP connections VPP A12 A7 A6 A5 A4 A3 A2 A1 A0 Q0 Q1 Q2 VSS 1 28 2 27 3 26 4 25 5 24 6 23 7 22 M27C256B 8 21 9 20 10 19 11 18 12 17 13 16 14 15 AI00756 6/24 VCC A14 A13 A8 A9 A11 G A10 E Q7 Q6 Q5 Q4 Q3 M27C256B Summary description A7 A12 VPP DU VCC A14 A13 LCC connections 1 32 9 M27C256B 25 A8 A9 A11 NC G A10 E Q7 Q6 17 VSS DU Q3 Q4 Q5 A6 A5 A4 A3 A2 A1 A0 NC Q0 Q1 Q2 Figure 3. AI00757 7/24 Device operation 2 M27C256B 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 VPP and 12V on A9 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 (tAVQV) is equal to the delay from E to output (tELQV). Data is available at the output after delay of tGLQV from the falling edge of G, assuming that E has been low and the addresses have been stable for at least tAVQV-tGLQV. 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 M27C256B 2.4 Device operation System considerations The power switching characteristics of Advance CMOS EPROMs require careful decoupling of the devices. The supply current, ICC, has three segments 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 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 VCC 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 VCC and VSS for every eight devices. The 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 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 VPP input is at 12.75V, G is at VIH and E is pulsed to VIL. The data to be programmed is applied to 8 bits in parallel to the data output pins. The levels required for the address and data inputs are TTL. VCC is specified to be 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 Device operation Figure 4. M27C256B Programming flowchart VCC = 6.25V, VPP = 12.75V n=0 E = 100µs Pulse NO ++n = 25 YES FAIL NO ++ Addr VERIFY YES Last Addr NO YES CHECK ALL BYTES 1st: VCC = 6V 2nd: VCC = 4.2V 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 VPP at 12.75V, will 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 VIL, E at VIH, VPP at 12.75V and VCC at 6.25V. 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 VCC = VPP = 5V. 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 Electronic Signature mode. Byte 0 (A0 = VIL) represents the manufacturer code and byte 1 (A0 = VIH) the device identifier code. For the STMicroelectronics M27C256B, these two identifier bytes are given in Table 3 and can be read-out on outputs Q7 to Q0. 10/24 M27C256B 2.10 Device operation 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 should be a minimum of 15 W-sec/cm2. The erasure time with this dosage is approximately 15 to 20 minutes using an ultraviolet lamp with 12000 µW/cm2 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. Operating modes(1) Table 2. Mode E G A9 VPP Q7-Q0 Read VIL VIL X VCC Data Out Output Disable VIL VIH X VCC Hi-Z VIL Pulse VIH X VPP Data In Verify VIH VIL X VPP Data Out Program Inhibit VIH VIH X VPP Hi-Z Standby VIH X X VCC Hi-Z Electronic Signature VIL VIL VID VCC Codes Program 1. X = VIH or VIL, VID = 12V ± 0.5V. Table 3. Electronic signature Identifier A0 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 Hex Data Manufacturer’s Code VIL 0 0 1 0 0 0 0 0 20h Device Code VIH 1 0 0 0 1 1 0 1 8Dh 11/24 Maximum rating 3 M27C256B 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 TA Parameter Ambient Operating Temperature(1) Value Unit –40 to 125 °C TBIAS Temperature Under Bias –50 to 125 °C TSTG Storage Temperature –65 to 150 °C VIO(2) Input or Output Voltage (except A9) –2 to 7 V Supply Voltage –2 to 7 V –2 to 13.5 V –2 to 14 V VCC VA9(2) VPP A9 Voltage Program Supply Voltage 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 VCC +0.5V with possible overshoot to VCC +2V for a period less than 20ns. 12/24 M27C256B 4 DC and AC parameters 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 1.5V 0.8V and 2V Input and Output Timing Ref. Voltages Figure 5. AC testing input output waveform High Speed 3V 1.5V 0V Standard 2.4V 0.4V 2.0V 0.8V AI01822 13/24 DC and AC parameters Figure 6. M27C256B AC testing load circuit 1.3V 1N914 3.3kΩ DEVICE UNDER TEST OUT CL CL = 30pF for High Speed CL = 100pF for Standard CL includes JIG capacitance Table 6. Capacitance(1) (2) Symbol CIN COUT AI01823B Parameter Input Capacitance Output Capacitance Test Condition Min Max Unit VIN = 0V 6 pF VOUT = 0V 12 pF 1. Sampled only, not 100% tested. 2. (TA = 25 °C, f = 1 MHz) Table 7. Symbol Read mode DC characteristics(1) (2) Parameter Test Condition Min Max Unit 0V ≤VIN ≤VCC ±10 µA 0V ≤VOUT ≤VCC ±10 µA E = VIL, G = VIL, IOUT = 0mA, f = 5MHz 30 mA E = VIH 1 mA E > VCC – 0.2V 100 µA VPP = VCC 100 µA ILI Input Leakage Current ILO Output Leakage Current ICC Supply Current ICC1 Supply Current (Standby) TTL ICC2 Supply Current (Standby) CMOS IPP Program Current VIL Input Low Voltage –0.3 0.8 V VIH(3) Input High Voltage 2 VCC + 1 V VOL Output Low Voltage IOL = 2.1mA 0.4 V Output High Voltage TTL IOH = –1mA 3.6 V IOH = –100µA VCC – 0.7V V VOH Output High Voltage CMOS 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. 2. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP. 3. Maximum DC voltage on Output is VCC +0.5V. 14/24 M27C256B DC and AC parameters Table 8. Symbol Programming mode DC characteristics(1) (2) Parameter Test Condition Min VIL ≤VIN ≤VIH Max Unit ±10 µA 50 mA 50 mA ILI Input Leakage Current ICC Supply Current IPP Program Current VIL Input Low Voltage –0.3 0.8 V VIH Input High Voltage 2 VCC + 0.5 V VOL Output Low Voltage IOL = 2.1mA 0.4 V VOH Output High Voltage TTL IOH = –1mA VID A9 Voltage E = VIL 3.6 11.5 V 12.5 V 1. TA = 25 °C; VCC = 6.25V ± 0.25V; VPP = 12.75V ± 0.25V. 2. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP. 15/24 DC and AC parameters Figure 7. M27C256B Read mode AC waveforms VALID A0-A14 VALID tAVQV tAXQX E tEHQZ tGLQV G tGHQZ tELQV Hi-Z Q0-Q7 AI00758B ) Table 9. Read mode AC characteristics(1) (2) M27C256B Symbol Alt Parameter Test Condition -45(3) -60 -70 -80 Unit Min Max Min Max Min Max Min Max tAVQV tACC Address Valid to Output Valid E = VIL, G = VIL 45 60 70 80 ns tELQV tCE Chip Enable Low to Output Valid G = VIL 45 60 70 80 ns tGLQV tOE Output Enable Low to Output Valid E = VIL 25 30 35 40 ns tEHQZ(4) tDF Chip Enable High to Output Hi-Z G = VIL 0 25 0 30 0 30 0 30 ns tGHQZ(4) tDF Output Enable High to Output Hi-Z E = VIL 0 25 0 30 0 30 0 30 ns E = VIL, G = VIL 0 tAXQX Address Transition tOH to Output Transition 0 0 0 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 2. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP. 3. Speed obtained with High Speed AC measurement conditions. 4. Sampled only, not 100% tested. 16/24 ns M27C256B DC and AC parameters ) Table 10. Read mode AC characteristics 2(1) (2) M27C256B Symbol Alt Parameter Test Condition -90 -10 -12 -15/-20/-25 Unit Min Max Min Max Min Max Min Max tAVQV tACC Address Valid to Output Valid E = VIL, G = VIL 90 100 120 150 ns tELQV tCE Chip Enable Low to Output Valid G = VIL 90 100 120 150 ns tGLQV Output Enable tOE Low to Output Valid E = VIL 40 50 60 65 ns tEHQZ(3) tDF tGHQZ(3) tAXQX Chip Enable High to Output Hi-Z G = VIL 0 30 0 30 0 40 0 50 ns Output Enable tDF High to Output Hi-Z E = VIL 0 30 0 30 0 40 0 50 ns Address tOH Transition to Output Transition E = VIL, G = VIL 0 0 0 0 ns 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 2. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP. 3. Sampled only, not 100% tested. 17/24 DC and AC parameters Figure 8. M27C256B Programming and Verify modes AC waveforms VALID A0-A14 tAVEL Q0-Q7 DATA IN tQVEL DATA OUT tEHQX VPP tVPHEL tGHQZ tGLQV VCC tVCHEL tGHAX E tELEH tQXGL G PROGRAM VERIFY AI00759 Table 11. Programming mode AC characteristics(1) (2) Parameter Test Condition Symbol Alt Min Max tAVEL tAS Address Valid to Chip Enable Low 2 µs tQVEL tDS Input Valid to Chip Enable Low 2 µs tVPHEL tVPS VPP High to Chip Enable Low 2 µs tVCHEL tVCS VCC High to Chip Enable Low 2 µs tELEH tPW Chip Enable Program Pulse Width 95 tEHQX tDH Chip Enable High to Input Transition 2 µs tQXGL tOES Input Transition to Output Enable Low 2 µs tGLQV tOE Output Enable Low to Output Valid tGHQZ tDFP Output Enable High to Output Hi-Z 0 tGHAX tAH Output Enable High to Address Transition 0 105 µs 100 ns 130 ns 1. TA = 25 °C; VCC = 6.25V ± 0.25V; VPP = 12.75V ± 0.25V. 2. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP. 18/24 Unit ns M27C256B 5 Package mechanical Package mechanical Figure 9. FDIP28WB - 28 pin Ceramic Frit-seal DIP, with window, package outline A2 A3 A A1 B1 B L α e eA D2 C 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 A Max Typ Min 5.72 Max 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 – – – – C 0.23 0.30 0.009 0.012 D 36.50 37.34 1.437 1.470 B1 1.45 0.057 D2 33.02 – – 1.300 – – E 15.24 – – 0.600 – – 13.06 13.36 0.514 0.526 E1 e 2.54 – – 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 – – – – α 4° 11° 4° 11° N 28 ∅ 7.11 0.280 28 19/24 Package mechanical M27C256B Figure 10. PDIP28 - 28 pin Plastic DIP, 600 mils width, package outline A2 A A1 B1 B L α e1 eA D2 C 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 Max Typ A 4.445 0.1750 A1 0.630 0.0248 A2 3.810 B 0.450 0.0177 B1 1.270 0.0500 C 3.050 4.570 0.230 0.310 0.1500 Min Max 0.1201 0.1799 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 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 15.200 16.680 0.5984 0.6567 eB L 20/24 Min 0.6000 3.300 0.1299 S 1.78 2.08 0.070 0.082 α 0° 10° 0° 10° N 28 28 M27C256B Package mechanical Figure 11. PLCC32 - 32 pin Rectangular Plastic Leaded Chip Carrier, package outline D D1 A1 A2 1 N B1 E2 e E1 E E3 F B 0.51 (.020) E2 1.14 (.045) A D3 R D2 CP 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 A 3.17 A1 Min Max 3.56 0.125 0.140 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 Typ 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 – – – – 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 D3 7.62 0.300 E3 10.16 – – 0.400 – – e 1.27 – – 0.050 – – 0.00 0.13 0.000 0.005 – – – – F R N 0.89 32 0.035 32 21/24 Part numbering 6 M27C256B 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 -45 (1)= 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 VCC Tolerance 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 M27C256B 7 Revision history Revision history Table 16. Date Document revision history 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.) 29-Aug-2002 1.4 Package mechanical data clarified for PDIP28 (Table 13.), PLCC32 (Table 14., Figure 11.) and TSOP28 (Table 15., Figure 13.) 2 Document converted to new template (sections added, information moved). TSOP28 package removed. Packages are ECOPACK® compliant. X option removed from Table 15: Ordering information scheme. 18-May-2006 23/24 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. All ST products are sold pursuant to ST’s terms and conditions of sale. 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