27LV256 256K (32K x 8) Low-Voltage CMOS EPROM 28 27 26 25 24 23 22 21 20 19 18 17 16 15 VCC A14 A13 A8 A9 A11 OE A10 CE O7 O6 O5 O4 O3 30 1 31 32 2 5 29 6 28 7 27 8 9 10 11 26 25 24 23 A8 A9 A11 NC OE A10 CE O7 O6 20 19 18 17 21 16 22 13 15 12 14 A6 A5 A4 A3 A2 A1 A0 NC O0 3 4 A7 A12 VPP NU Vcc A14 A13 PLCC •1 2 3 4 5 6 7 8 9 10 11 12 13 14 SOIC VPP A12 A7 A6 A5 A4 A3 A2 A1 A0 O0 O1 O2 VSS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 27LV256 The Microchip Technology Inc. 27LV256 is a low voltage (3.0 volt) CMOS EPROM designed for battery powered applications. The device is organized as a 32K x 8 (32K-Byte) non-volatile memory product. The 27LV256 consumes only 8 mA maximum of active current during a 3.0 volt read operation therefore improving battery performance. This device is designed for very low voltage applications where conventional 5.0 volt only EPROMS can not be used. Accessing individual bytes from an address transition or from power-up (chip enable pin going low) is accomplished in less than 200 ns at 3.0V. This device allows systems designers the ability to use low voltage non-volatile memory with today’s' low voltage microprocessors and peripherals in battery powered applications. VPP A12 A7 A6 A5 A4 A3 A2 A1 A0 O0 O1 O2 VSS 27LV256 DESCRIPTION PDIP 27LV256 • Wide voltage range 3.0V to 5.5V • High speed performance - 200 ns access time available at 3.0V • CMOS Technology for low power consumption - 8 mA Active current at 3.0V - 20 mA Active current at 5.5V - 100 µA Standby current • Factory programming available • Auto-insertion-compatible plastic packages • Auto ID aids automated programming • Separate chip enable and output enable controls • High speed “Express” programming algorithm • Organized 32K x 8: JEDEC standard pinouts - 28-pin Dual-in-line package - 32-pin PLCC package - 28-pin SOIC package - Tape and reel • Data Retention > 200 years • Available for the following temperature ranges: - Commercial: 0˚C to +70˚C - Industrial: -40˚C to +85˚C PACKAGE TYPES O1 O2 VSS NU O3 O4 O5 FEATURES 28 27 26 25 24 23 22 21 20 19 18 17 16 15 VCC A14 A13 A8 A9 A11 OE A10 CE O7 O6 O5 O4 O3 A complete family of packages is offered to provide the most flexibility in applications. For surface mount applications, PLCC or SOIC packaging is available. Tape and reel packaging is also available for PLCC or SOIC packages. 1998 Microchip Technology Inc. DS11020G-page 1 27LV256 1.0 ELECTRICAL CHARACTERISTICS 1.1 Maximum Ratings* TABLE 1-1: PIN FUNCTION TABLE Name Function A0-A14 Address Inputs VCC and input voltages w.r.t. VSS ........ -0.6V to +7.25V CE Chip Enable VPP voltage w.r.t. VSS during programming ......................................... -0.6V to +14V OE Output Enable Voltage on A9 w.r.t. VSS ....................... -0.6V to +13.5V VPP Programming Voltage Output voltage w.r.t. VSS .................-0.6V to VCC +1.0V O0 - O7 Storage temperature .......................... -65˚C to +150˚C VCC +5V or +3V Power Supply Ambient temp. with power applied...... -65˚C to +125˚C VSS Ground NC No Connection; No Internal Connection NU Not Used; No External Connection Is Allowed *Notice: Stresses above those listed under “Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. TABLE 1-2: Data Output READ OPERATION DC CHARACTERISTICS VCC = +5V ±10% or 3.0V where indicated Commercial: Tamb = 0˚C to +70˚C Industrial: Tamb = -40˚C to +85˚C Parameter Part* Status Symbol Min. Max. Units Conditions Input Voltages all Logic "1" Logic "0" VIH VIL 2.0 -0.5 VCC+1 0.8 V V Input Leakage all ILI -10 10 µA VIN = 0 to VCC Output Voltages all Logic "1" Logic "0" VOH VOL 2.4 0.45 V V IOH = -400 µA IOL = 2.1 mA 10 µA VOUT = 0V to VCC Output Leakage all — ILO -10 Input Capacitance all — CIN — 6 pF VIN = 0V; Tamb = 25°C; f = 1 MHz Output Capacitance all — COUT — 12 pF VOUT = 0V; Tamb = 25°C; f = 1 MHz Power Supply Current, Active C TTL input ICC1 — I TTL input ICC2 — 20 @ 5.0V 8 @ 3.0V 25 @ 5.0V 10 @ 3.0V mA mA mA mA VCC = 5.5V; VPP = VCC f = 1 MHz; OE = CE = VIL; IOUT = 0 mA; VIL = -0.1 to 0.8V; VIH = 2.0 to VCC; Note 1 C I all TTL input TTL input CMOS input ICC(S) — 1 @ 3.0V 2 @ 3.0V 100 @ 3.0V mA mA µA Power Supply Current, Standby CE=VCC ± 0.2V * Parts: C=Commercial Temperature Range I =Industrial Temperature Ranges Note 1: Typical active current increases .75 mA per MHz up to operating frequency for all temperature ranges. DS11020G-page 2 1998 Microchip Technology Inc. 27LV256 TABLE 1-3: READ OPERATION AC CHARACTERISTICS AC Testing Waveform: Output Load: Input Rise and Fall Times: Ambient Temperature: Parameter VIH = 2.4V and VIL = 0.45V; VOH = 2.0V VOL = 0.8V 1 TTL Load + 100 pF 10 ns Commercial: Tamb = 0˚C to +70˚C Industrial: Tamb = -40˚C to +85˚C 27HC256-20 27HC256-25 27HC256-30 Min Max Min Max Min Max Sym Units Conditions Address to Output Delay tACC — 200 — 250 — 300 ns CE = OE = VIL CE to Output Delay tCE — 200 — 250 — 300 ns OE = VIL OE to Output Delay tOE — 100 — 125 — 125 ns CE = VIL CE or OE to O/P High Impedance tOFF 0 50 0 50 0 50 ns Output Hold from Address CE or OE, whichever goes first tOH 0 — 0 — 0 — ns FIGURE 1-1: READ WAVEFORMS VIH Address valid Address VIL VIH CE VIL t CE(2) VIH OE VIL Outputs O0 - O7 VOH t OFF(1,3) t OH t OE(2) High Z Valid Output High Z VOL t ACC Notes: (1) tOFF is specified for OE or CE, whichever occurs first (2) OE may be delayed up to t CE - tOE after the falling edge of CE without impact on tCE (3) This parameter is sampled and is not 100% tested. 1998 Microchip Technology Inc. DS11020G-page 3 27LV256 TABLE 1-4: PROGRAMMING DC CHARACTERISTICS Ambient Temperature: Tamb = 25°C ± 5°C VCC = 6.5V ± 0.25V, VPP = 13.0V ± 0.25V Parameter Status Symbol Min Max. Units Input Voltages Logic”1” Logic”0” VIH VIL 2.0 -0.1 VCC+1 0.8 V V Input Leakage — ILI -10 10 µA VIN = 0V to VCC Logic”1” Logic”0” VOH VOL 2.4 0.45 V V IOH = -400 µA IOL = 2.1 mA VCC Current, program & verify — ICC2 — 20 mA Note 1 VPP Current, program — IPP2 — 25 mA Note 1 A9 Product Identification — VH 11.5 12.5 V Output Voltages Conditions Note 1: VCC must be applied simultaneously or before VPP and removed simultaneously or after VPP. TABLE 1-5: PROGRAMMING AC CHARACTERISTICS for Program, Program Verify and Program Inhibit Modes Parameter AC Testing Waveform: VIH=2.4V and VIL=0.45V; VOH=2.0V; VOL=0.8V Output Load: 1 TLL Load + 100pF Ambient Temperature: Tamb=25°C±5°C VCC= 6.5V ± 0.25V, VPP =13.0V ± 0.25V Symbol Min. Max. Units Address Set-Up Time tAS 2 — µs Data Set-Up Time tDS 2 — µs Data Hold Time tDH 2 — µs Address Hold Time tAH 0 — µs Float Delay (2) tDF 0 130 ns VCC Set-Up Time tVCS 2 — µs Program Pulse Width (1) tPW 95 105 µs CE Set-Up Time tCES 2 — µs OE Set-Up Time tOES 2 — µs VPP Set-Up Time tVPS 2 — µs Data Valid from OE tOE — 100 ns Remarks 100 µs typical Note 1: For express algorithm, initial programming width tolerance is 100 µs ±5%. 2: This parameter is only sampled and not 100% tested. Output float is defined as the point where data is no longer driven (see timing diagram). DS11020G-page 4 1998 Microchip Technology Inc. 27LV256 FIGURE 1-2: PROGRAMMING WAVEFORMS Program Verify VIH Address Address Stable VIL t AS t AH VIH High Z Data Data Stable VIL t DS Data Out Valid t DF (1) t DH 13.0V(2) VPP t VPS 5.0V 6.5V(2) VCC t VCS 5.0V VIH CE VIL OE t OPW VIL Notes: TABLE 1-6: t OES t PW VIH t OE (1) (1) t DF and tOE are characteristics of the device but must be accommodated by the programmer (2) VCC = 6.5V ±0.25V, VPP = VH = 13.0V ±0.25V for express algorithm MODES Operation Mode CE OE VPP A9 O0 - O7 Read VIL VIL VCC X DOUT Program VIL VIH VH X DIN Program Verify VIH VIL VH X DOUT Program Inhibit VIH VIH VH X High Z Standby VIH X VCC X High Z Output Disable VIL VIH VCC X High Z Identity VIL VIL VCC VH Identity Code X = Don’t Care 1.2 Read Mode (See Timing Diagrams and AC Characteristics) Read Mode is accessed when: a) b) For Read operations, if the addresses are stable, the address access time (tACC) is equal to the delay from CE to output (tCE). Data is transferred to the output after a delay from the falling edge of OE (tOE). the CE pin is low to power up (enable) the chip the OE pin is low to gate the data to the output pins 1998 Microchip Technology Inc. DS11020G-page 5 27LV256 1.3 Standby Mode The standby mode is defined when the CE pin is high (VIH) and a program mode is not defined. Output Disable 1.4 Output Enable 1.6 After the array has been programmed it must be verified to ensure that all the bits have been correctly programmed. This mode is entered when all of the following conditions are met: This feature eliminates bus contention in multiple bus microprocessor systems and the outputs go to a high impedance when the following condition is true: a) b) c) d) • The OE pin is high and program mode is not defined. 1.7 1.5 Programming Mode The Express algorithm has been developed to improve on the programming throughput times in a production environment. Up to 10 100-microsecond pulses are applied until the byte is verified. No over-programming is required. A flowchart of the express algorithm is shown in Figure 1. Programming takes place when: a) b) c) d) VCC is brought to the proper voltage VPP is brought to the proper VH level the OE pin is high the CE pin is low Since the erased state is “1” in the array, programming of “0” is required. The address to be programmed is set via pins A0-A14 and the data to be programmed is presented to pins O0-O7. When data and address are stable, a low-going pulse on the CE line programs that location. Verify VCC is at the proper level VPP is at the proper VH level the CE pin is high the OE line is low Inhibit When Programming multiple devices in parallel with different data, only CE needs to be under separate control to each device. By pulsing the CE line low on a particular device, that device will be programmed, and all other devices with CE held high will not be programmed with the data although address and data are available on their input pins. 1.8 Identity Mode In this mode specific data is outputted which identifies the manufacturer as Microchip Technology Inc. and device type. This mode is entered when Pin A9 is taken to VH (11.5V to 12.5V). The CE and OE lines must be at VIL. A0 is used to access any of the two non-erasable bytes whose data appears on O0 through O7. Pin Identity Manufacturer Device Type* Input Output A0 0 O O O O O O O H 7 6 5 4 3 2 1 0 e x VIL VIH 0 0 1 0 1 0 0 1 29 1 0 0 0 1 1 0 0 8C * Code subject to change. DS11020G-page 6 1998 Microchip Technology Inc. 27LV256 FIGURE 1-3: PROGRAMMING EXPRESS ALGORITHM Conditions: Tamb = 25+/-5C VCC = 6.5+/-0.25V VPP = 13.0+/-0.25V Start ADDR = First Location VCC = 6.5V VPP = 13.0V X=0 Program one 100 µs pulse Increment X Verify Byte Pass Fail No X = 10? Last Address? Yes Device Failed Yes No Increment Address VCC = VPP = 4.5V, 5.5V Device Passed 1998 Microchip Technology Inc. Yes All bytes = original data? No Device Failed DS11020G-page 7 27LV256 NOTES: DS11020G-page 8 1998 Microchip Technology Inc. 27LV256 NOTES: 1998 Microchip Technology Inc. DS11020G-page 9 27LV256 NOTES: DS11020G-page 10 1998 Microchip Technology Inc. 27LV256 27LV256 Product Identification System To order or to obtain information, e.g., on pricing or delivery, please use the listed part numbers, and refer to the factory or the listed sales offices. 27LV256 – 25 I /P Package: Temperature Range: Access Time: Device: 1998 Microchip Technology Inc. L = Plastic Leaded Chip Carrier P = Plastic DIP (600 Mil) SO = Plastic SOIC (300 Mil) Blank = 0˚C to +70˚C I = -40˚C to +85˚C 20 = 200 ns 25 = 250 ns 30 = 300 ns (SOIC only) 27LV256 256K (32K x 8) Low-Voltage CMOS EPROM DS11020G-page 11 Note the following details of the code protection feature on PICmicro® MCUs. • • • • • • The PICmicro family meets the specifications contained in the Microchip Data Sheet. Microchip believes that its family of PICmicro microcontrollers is one of the most secure products of its kind on the market today, when used in the intended manner and under normal conditions. There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the PICmicro microcontroller in a manner outside the operating specifications contained in the data sheet. The person doing so may be engaged in theft of intellectual property. Microchip is willing to work with the customer who is concerned about the integrity of their code. Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable”. Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our product. If you have any further questions about this matter, please contact the local sales office nearest to you. Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. Use of Microchip’s products as critical components in life support systems is not authorized except with express written approval by Microchip. No licenses are conveyed, implicitly or otherwise, under any intellectual property rights. Trademarks The Microchip name and logo, the Microchip logo, FilterLab, KEELOQ, microID, MPLAB, PIC, PICmicro, PICMASTER, PICSTART, PRO MATE, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. dsPIC, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, microPort, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, MXDEV, PICC, PICDEM, PICDEM.net, rfPIC, Select Mode and Total Endurance are trademarks of Microchip Technology Incorporated in the U.S.A. Serialized Quick Turn Programming (SQTP) is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. © 2002, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. 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