M27W256 256 Kbit (32Kb x 8) Low Voltage UV EPROM and OTP EPROM ■ 2.7V to 3.6V SUPPLY VOLTAGE in READ OPERATION ■ ACCESS TIME: – 70ns at VCC = 3.0V to 3.6V – 80ns at VCC = 2.7V to 3.6V 28 28 ■ PIN COMPATIBLE with M27C256B ■ LOW POWER CONSUMPTION: 1 1 – 15µA max Standby Current FDIP28W (F) PDIP28 (B) – 15mA max Active Current at 5MHz ■ PROGRAMMING TIME 100µs/byte ■ HIGH RELIABILITY CMOS TECHNOLOGY – 2,000V ESD Protection – 200mA Latchup Protection Immunity ■ PLCC32 (K) TSOP28 (N) 8 x 13.4mm ELECTRONIC SIGNATURE – Manufacturer Code: 20h – Device Code: 3Dh DESCRIPTION The M27W256 is a low voltage 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 M27W256 operates in the read mode with a supply voltage as low as 3V. The decrease in operating power allows either a reduction of the size of the battery or an increase in the time between battery recharges. 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 M27W256 is offered in PDIP28, PLCC32 and TSOP28 (8 x 13.4 mm) packages. Figure 1. Logic Diagram VCC VPP 15 8 A0-A14 E Q0-Q7 M27W256 G VSS AI03629 March 2000 1/15 M27W256 VCC A14 A13 A8 A9 A11 G A10 E Q7 Q6 Q5 Q4 Q3 1 28 2 27 3 26 4 25 5 24 6 23 7 22 M27W256 8 21 9 20 10 19 11 18 12 17 13 16 14 15 1 32 A6 A5 A4 A3 A2 A1 A0 NC Q0 9 M27W256 25 17 AI03627 AI03626 Figure 2C. TSOP Connections G A11 A9 A8 A13 A14 VCC VPP A12 A7 A6 A5 A4 A3 22 28 1 7 Table 1. Signal Names 21 M27W256 15 14 8 AI03628 2/15 A8 A9 A11 NC G A10 E Q7 Q6 Q1 Q2 VSS DU Q3 Q4 Q5 VPP A12 A7 A6 A5 A4 A3 A2 A1 A0 Q0 Q1 Q2 VSS Figure 2B. LCC Connections A7 A12 VPP DU VCC A14 A13 Figure 2A. DIP Connections A10 E Q7 Q6 Q5 Q4 Q3 VSS Q2 Q1 Q0 A0 A1 A2 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 M27W256 Table 2. Absolute Maximum Ratings (1) Symbol Parameter Value Unit Ambient Operating Temperature (3) –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 TA VCC VA9 (2) A9 Voltage Program Supply Voltage VPP Note: 1. Except for the rating ”Operating Temperature Range”, stresses above those listed in the Table ”Absolute Maximum Ratings” 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. 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. 3. Depends on range. Table 3. Operating Modes E G A9 VPP Q7-Q0 Read V IL VIL X VCC Data Out Output Disable V IL 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 V IL VIL VID VCC Codes Mode Program Note: X = VIH or VIL, VID = 12V ± 0.5V. Table 4. 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 3/15 M27W256 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 3. AC Testing Input Output Waveform Figure 4. AC Testing Load Circuit 1.3V High Speed 1N914 3V 1.5V 3.3kΩ 0V DEVICE UNDER TEST Standard 2.4V OUT CL 2.0V 0.8V 0.4V AI01822 CL = 30pF for High Speed CL = 100pF for Standard CL includes JIG capacitance AI01823B Table 6. Capacitance (1) (TA = 25 °C, f = 1 MHz) Symbol C IN COUT Parameter Input Capacitance Output Capacitance Test Condit ion Min Max Unit VIN = 0V 6 pF VOUT = 0V 12 pF Note: 1. Sampled only, not 100% tested. DEVICE OPERATION The modes of operation of the M27W256 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. Read Mode The M27W256 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, indepen- 4/15 dent 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 t GLQV from the falling edge of G, assuming that E has been low and the addresses have been stable for at least tAVQV-tGLQV. Standby Mode The M27W256 has a standby mode which reduces the supply current from 10mA to 10µA with low voltage operation VCC ≤ 3.6V, see Read Mode DC Characteristics table for details. The M27W256 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. M27W256 Table 7. Read Mode DC Characteristics (1) (TA = –40 to 85°C; VCC = 2.7V to 3.6V; VPP = VCC) Symbol Parameter ILI Input Leakage Current ILO Output Leakage Current ICC Supply Current Test Condition Min Max Unit 0V ≤ VIN ≤ V CC ±10 µA 0V ≤ VOUT ≤ VCC ±10 µA E = VIL, G = VIL, IOUT = 0mA, f = 5MHz, 15 mA E = VIH 1 mA E > VCC – 0.2V, VCC ≤ 3.6V 15 µA VPP = VCC 100 µA VCC ≤ 3.6V ICC1 Supply Current (Standby) TTL ICC2 Supply Current (Standby) CMOS IPP Program Current VIL Input Low Voltage –0.6 0.2 VCC V VIH (2) Input High Voltage 0.7 VCC VCC + 0.5 V VOL Output Low Voltage 0.4 V VOH Output High Voltage TTL IOL = 2.1mA IOH = –400µA 2.4 V Note: 1. VCC must be applied simultaneously with or before VPP and removed simultaneously or after V PP. 2. Maximum DC voltage on Output is VCC +0.5V. Table 8. Read Mode AC Characteristics (1) (TA = –40 to 85°C; VCC = 2.7V to 3.6V; VPP = VCC) M27W256 Symbol Alt Parameter -100 (-120/-150/-200) -80 (3) Test Condition Unit VCC = 3.0V to 3.6V VCC = 2.7V to 3.6V VCC = 2.7V to 3.6V Min Max Min Max Min Max tAVQV tACC Address Valid to Output Valid E = VIL, G = VIL 70 80 100 ns tELQV tCE Chip Enable Low to Output Valid G = VIL 70 80 100 ns tGLQV tOE Output Enable Low to Output Valid E = VIL 40 50 60 ns tEHQZ (2) tDF Chip Enable High to Output Hi-Z G = VIL 0 40 0 50 0 60 ns tGHQZ (2) tDF Output Enable High to Output Hi-Z E = VIL 0 40 0 50 0 60 ns tAXQX tOH Address Transition to Output Transition E = VIL, G = VIL 0 0 0 ns Note: 1. VCC must be applied simultaneously with or before VPP and removed simultaneously or after V PP. 2. Sampled only, not 100% tested. 3. Speed obtained with High Speed AC measurement conditions. 5/15 M27W256 Figure 5. Read Mode AC Waveforms A0-A14 VALID tAVQV VALID tAXQX E tGLQV tEHQZ G tELQV Q0-Q7 tGHQZ Hi-Z AI00758B 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: a. the lowest possible memory power dissipation, b. 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 hat the output pins are only active when data is desired from a particular memory device. 6/15 System Considerations The power switching characteristics of Advance CMOS EPROMs require careful decoupling of the devices. The supply current, I CC, 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. M27W256 Table 9. Programming Mode DC Characteristics (1) (TA = 25 °C; VCC = 6.25V ± 0.25V; VPP = 12.75V ± 0.25V) Symbol Parameter Test Condition ILI Input Leakage Current VIL ≤ VIN ≤ VIH ICC Supply Current IPP Program Current VIL Input Low Voltage VIH Input High Voltage VOL Output Low Voltage IOL = 2.1mA VOH Output High Voltage TTL IOH = –1mA VID A9 Voltage Min Max Unit ±10 µA 50 mA 50 mA –0.3 0.8 V 2 VCC + 0.5 V 0.4 V E = VIL 3.6 11.5 V 12.5 V Note: VCC must be applied simultaneously with or before V PP and removed simultaneously or after VPP. Table 10. Programming Mode AC Characteristics (1) (TA = 25 °C; VCC = 6.25V ± 0.25V; VPP = 12.75V ± 0.25V Symbol Alt Parameter 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 t EHQX 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 t GHAX tAH Output Enable High to Address Transition 0 105 Unit µs 100 ns 130 ns ns Note: VCC must be applied simultaneously with or before V PP and removed simultaneously or after VPP. Programming The M27W256 has been designed to be fully compatible with the M27C256B and has the same electronic signature. As a result the M27W256 can be programmed as the M27C256B on the same programming equipments applying 12.75V on VPP and 6.25V on VCC by the use of the same PRESTO II algorithm. When delivered (and after each erasure for UV EPROM), all bits of the M27W256 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 M27W256 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 6.25 V ± 0.25 V. 7/15 M27W256 Figure 6. Programming and Verify Modes AC Waveforms VALID A0-A14 tAVEL Q0-Q7 DATA IN tQVEL DATA OUT tEHQX VPP tGLQV tVPHEL tGHQZ VCC tVCHEL tGHAX E tELEH tQXGL G PROGRAM VERIFY AI00759 Figure 7. Programming Flowchart VCC = 6.25V, VPP = 12.75V n=0 P = 100µs Pulse NO ++n = 25 YES FAIL NO VERIFY ++ Addr YES Last Addr NO YES CHECK ALL WORDS 1st: VCC = 5V 2nd: VCC = 2.7V AI00707D 8/15 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 7). 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 at VCC much higher than 3.6V provides necessary margin to each programmed cell. Program Inhibit Programming of multiple M27W256s in parallel with different data is also easily accomplished. Except for E, all like inputs including G of the parallel M27W256 may be common. A TTL low level pulse applied to a M27W256’s E input, with VPP at 12.75 V, will program that M27W256. A high level E input inhibits the other M27W256s from being programmed. 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. M27W256 On-Board Programming The M27W256 can be directly programmed in the application circuit. See the relevant Application Note AN620. 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 M27W256. To activate the ES mode, the programming equipment must force 11.5V to 12.5V on address line A9 of the M27W256, 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 V IL during Electronic Signature mode. Byte 0 (A0 = VIL) represents the manufacturer code and byte 1 (A0 = VIH) the device identifier code. For the STMicroelectronics M27W256, these two identifier bytes are given in Table 4 and can be read-out on outputs Q7 to Q0. Note that the M27W256 and M27C256B have the same identifier bytes. ERASURE OPERATION (applies for UV EPROM) The erasure characteristics of the M27W256 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 M27W256 in about 3 years, while it would take approximately 1 week to cause erasure when exposed to direct sunlight. If the M27W256 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 M27W256 window to prevent unintentional erasure. The recommended erasure procedure for the M27W256 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 M27W256 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. 9/15 M27W256 Table 11. Ordering Information Scheme Example: M27W256 -80 K 6 TR Device Type M27 Supply Voltage W = 2.7V to 3.6V Device Function 256 = 256 Kbit (32Kb x 8) Speed -80 (1,2) = 80 ns -100 = 100 ns Not For New Design (3) -120 = 120 ns -150 = 150 ns -200 = 200 ns Package F = FDIP28W (4) B = PDIP28 K = PLCC32 N = TSOP28: 8 x 13.4 mm (4) Temperature Range 6 = –40 to 85 °C Optio ns TR = Tape & Reel Packing Note: 1. 2. 3. 4. High Speed, see AC Characteristics section for further information. This speed also guarantees 70ns access time at VCC = 3.0V to 3.6V. These speeds are replaced by the 100ns. Packages option available on request. Please contact STMicroelectronics local Sales Office. 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. 10/15 M27W256 Table 12. FDIP28W - 28 pin Ceramic Frit-seal DIP, with window, Package Mechanical Data mm Symb Typ inches Min Max A 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 B1 – – – – C 1.45 0.23 0.30 0.009 0.012 D 36.50 37.34 1.437 1.470 – – 1.300 – – 0.600 D2 33.02 E 15.24 E1 0.057 – – 13.06 13.36 – – 0.514 0.526 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 Figure 8. FDIP28W - 28 pin Ceramic Frit-seal DIP, with window, Package Outline A2 A3 A1 B1 B A L e α eA D2 C eB D S N ∅ E1 E 1 FDIPW-a Drawing is not to scale. 11/15 M27W256 Table 13. PDIP28 - 28 pin Plastic DIP, 600 mils width, Package Mechanical Data mm inches Symb Typ Min Max A – A1 Min Max 5.08 – 0.200 0.38 – 0.015 – A2 3.56 4.06 0.140 0.160 B 0.38 0.51 0.015 0.020 – – – – C 0.20 0.30 0.008 0.012 D 36.83 37.34 1.450 1.470 B1 1.52 Typ 0.060 D2 33.02 – – 1.300 – – E 15.24 – – 0.600 – – 13.59 13.84 0.535 0.545 E1 e1 2.54 – – 0.100 – – eA 14.99 – – 0.590 – – eB 15.24 17.78 0.600 0.700 L 3.18 3.43 0.125 0.135 S 1.78 2.08 0.070 0.082 α 0° 10° 0° 10° N 28 28 Figure 9. PDIP28 - 28 pin Plastic DIP, 600 mils width, Package Outline A2 A1 B1 B A L e1 α eA D2 C eB D S N E1 E 1 PDIP Drawing is not to scale. 12/15 M27W256 Table 14. PLCC32 - 32 lead Plastic Leaded Chip Carrier, Package Mechanical Data mm Symb Typ inches Min Max A 2.54 A1 Min Max 3.56 0.100 0.140 1.52 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 D 12.32 12.57 0.485 0.495 D1 11.35 11.56 0.447 0.455 D2 9.91 10.92 0.390 0.430 E 14.86 15.11 0.585 0.595 E1 13.89 14.10 0.547 0.555 E2 12.45 13.46 0.490 0.530 – – – – 0.00 0.25 0.000 0.010 – – – – e 1.27 F R 0.89 Typ 0.050 0.035 N 32 32 Nd 7 7 Ne 9 9 CP 0.10 0.004 Figure 10. PLCC32 - 32 lead Plastic Leaded Chip Carrier, Package Outline D D1 A1 A2 1 N B1 E1 E Ne e D2/E2 F B 0.51 (.020) 1.14 (.045) A Nd R CP PLCC Drawing is not to scale. 13/15 M27W256 Table 15. TSOP28 - 28 lead Plastic Thin Small Outline, 8 x 13.4 mm, Package Mechanical Data mm inch Symbol Typ Min Max Typ Min A 1.250 0.0492 A1 0.200 0.0079 A2 0.950 1.150 0.0374 0.0453 B 0.170 0.270 0.0067 0.0106 C 0.100 0.210 0.0039 0.0083 D 13.200 13.600 0.5197 0.5354 D1 11.700 11.900 0.4606 0.4685 – – – – E 7.900 8.100 0.3110 0.3189 L 0.500 0.700 0.0197 0.0276 α 0° 5° 0° 5° e 0.550 CP 0.0217 0.100 N 0.0039 28 28 Figure 11. TSOP28 - 28 lead Plastic Thin Small Outline, 8 x 13.4 mm, Package Outline A2 22 21 e 28 1 E B 7 8 D1 A CP D DIE C TSOP-c Drawing is not to scale 14/15 Max A1 α L M27W256 Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in lif e support devices or systems without express written approval of STMicroelectronics. The ST logo is registered trademark of STMicroelectronics 2000 STMicroelectronics - All Rights Reserved All other names are the property of their respective owners. STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A . http://w ww.st.com 15/15