Recommend System Management Alternative: X5043 X25020 2K 256 x 8 Bit SPI Serial EEPROM with Block Lock™ Protection DESCRIPTION • 2MHz clock rate • SPI modes (0,0 & 1,1) • 256 X 8 bits —16-byte page mode • Low power CMOS —10µA standby current —3mA active write current • 2.7V To 5.5V power supply • Block lock protection —Protect 1/4, 1/2 or all of EEPROM array • Built-in inadvertent write protection —Power-up/power-down protection circuitry —Write latch —Write protect pin • Self-timed write cycle —5ms write cycle time (typical) • High reliability —Endurance: 1,000,000 cycles per byte —Data retention: 100 years —ESD protection: 2000V on all pins • 8-lead SOIC Package The X25020 is a CMOS 2048-bit serial EEPROM, internally organized as 256 x 8. The X25020 features a serial interface and software protocol, allowing operation on a simple three-wire bus. The bus signals are a clock input (SCK) plus separate data in (SI) and data out (SO) lines. Access to the device is controlled through a chip select (CS) input, allowing any number of devices to share the same bus. N O FO T R RE N C EW O M D M ES EN IG D N ED S FEATURES The X25020 also features two additional inputs that provide the end user with added flexibility. By asserting the HOLD input, the X25020 will ignore transitions on its inputs, thus allowing the host to service higher priority interrupts. The WP input can be used as a hardwire input to the X25020 (disabling all write attempts), thus providing a mechanism for limiting end user capability of altering the memory. The X25020 utilizes Xicor’s proprietary Direct Write™ cell, providing a minimum endurance of 1,000,000 cycles per byte and a minimum data retention of 100 years. BLOCK DIAGRAM Status Register Write Protect Logic X Decode Logic 256 Byte Array 4 SO SI SCK CS HOLD Command Decode And Control Logic 4 X 128 4 4 X 128 16 WP Write Control and Timing Logic 16 X 128 16 8 Y Decode Data Register Direct Write™ and Block Lock™ Protection is a trademark of Xicor, Inc. REV 1.1 7/12/00 www.xicor.com Characteristics subject to change without notice. 1 of 13 X25020 PIN DESCRIPTIONS PIN CONFIGURATION Serial Output (SO) SO is a push/pull serial data output pin. During a read cycle, data is shifted out on this pin. Data is clocked out by the falling edge of the serial clock. SOIC 8 1 VCC N O FO T R RE N C EW O M D M ES EN IG D N ED S CS Serial Input (SI) SI is the serial data input pin. All opcodes, byte addresses, and data to be written to the memory are input on this pin. Data is latched by the rising edge of the serial clock. 7 HOLD 3 6 SCK 4 5 SI SO 2 WP VSS X25020 PIN NAMES Serial Clock (SCK) Symbol Description CS Chip Select Input SO Serial Output SI Serial Input SCK Serial Clock Input Chip Select (CS) WP Write Protect Input When CS is HIGH, the X25020 is deselected and the SO pin is at high impedance; unless an internal write operation is underway, the X25020 will be in the standby power mode. CS LOW enables the X25020, placing it in the active power mode. It should be noted that after power-up, a HIGH to LOW transition on CS is required prior to the start of any operation. VSS Ground VCC Supply Voltage HOLD Hold Input The Serial Clock controls the serial bus timing for data input and output. Opcodes, addresses, or data present on the SI pin are latched on the rising edge of the clock input, while data on the SO pin change after the falling edge of the clock input. Write Protect (WP) When WP is LOW, nonvolatile writes to the X25020 are disabled, but the part otherwise functions normally. When WP is held HIGH, all functions, including nonvolatile writes operate normally. WP going LOW while CS is still LOW will interrupt a write to the X25020. If the internal write cycle has already been initiated, WP going LOW will have no affect on a write. Hold (HOLD) HOLD is used in conjunction with the CS pin to select the device. Once the part is selected and a serial sequence is underway, HOLD may be used to pause the serial communication with the controller without resetting the serial sequence. To pause, HOLD must be brought LOW while SCK is LOW. To resume communication, HOLD is brought HIGH, again while SCK is LOW. If the pause feature is not used, HOLD should be held HIGH at all times. REV 1.1 7/12/00 PRINCIPLES OF OPERATION The X25020 is a 256 x 8 EEPROM designed to interface directly with the synchronous serial peripheral interface (SPI) of many popular microcontroller families. The X25020 contains an 8-bit instruction register. It is accessed via the SI input, with data being clocked in on the rising SCK. CS must be LOW and the HOLD and WP inputs must be HIGH during the entire operation. Table 1 contains a list of the instructions and their opcodes. All instructions, addresses and data are transferred MSB first. Data input is sampled on the first rising edge of SCK after CS goes LOW. SCK is static, allowing the user to stop the clock and then resume operations. If the clock line is shared with other peripheral devices on the SPI bus, the user can assert the HOLD input to place the X25020 into a “PAUSE” condition. After releasing HOLD, the X25020 will resume operation from the point when HOLD was first asserted. www.xicor.com Characteristics subject to change without notice. 2 of 13 X25020 Status Register The RDSR instruction provides access to the status register. The status register may be read at any time, even during a write cycle. The status register is formatted as follows: 7 0 The Write-In-Process (WIP) bit indicates whether the X25020 is busy with a write operation. When set to a “1”, a write is in progress, when set to a “0”, no write is in progress. During a write, all other bits are set to “1”. The Write Enable Latch (WEL) bit indicates the status of the “write enable” latch. When set to a “1”, the latch is set, when set to a “0”, the latch is reset. N O FO T R RE N C EW O M D M ES EN IG D N ED S Write Enable Latch The X25020 contains a “write enable” latch. This latch must be SET before a write operation will be completed internally. The WREN instruction will set the latch and the WRDI instruction will reset the latch. This latch is automatically reset upon a power-up condition and after the completion of a byte, page, or status register write cycle. 6 5 4 3 2 1 0 0 0 0 BP1 BP0 WEL WIP BP0 and BP1 are set by the WRSR instruction. WEL and WIP are read-only and automatically set by other operations. The Block Protect (BP0 and BP1) bits are nonvolatile and allow the user to select one of four levels of protection. The X25020 is divided into four 512-bit segments. One, two, or all four of the segments may be protected. That is, the user may read the segments but will be unable to alter (write) data within the selected segments. The partitioning is controlled as illustrated below. Status Register Bits BP1 BP0 Array Addresses Protected 0 0 None 0 1 $C0–$FF 1 0 $80–$FF 1 1 $00–$FF Table 1. Instruction Set Instruction Name Instruction Format* Operation WREN 0000 0110 Set the write enable latch (enable write operations) WRDI 0000 0100 Reset the write enable latch (disable write operations) RDSR 0000 0101 Read status register WRSR 0000 0001 Write status register READ 0000 0011 Read data from memory array beginning at selected address WRITE 0000 0010 Write data to memory array beginning at selected address (1 to 32 bytes) Notes: *Instructions are shown MSB in leftmost position. Instructions are transferred MSB first. Clock and Data Timing Data input on the SI line is latched on the rising edge of SCK. Data is output on the SO line by the falling edge of SCK. Read Sequence When reading from the EEPROM memory array, CS is first pulled LOW to select the device. The 8-bit READ instruction is transmitted to the X25020, followed by the 8-bit address. After the read opcode and address are sent, the data stored in the memory at the selected REV 1.1 7/12/00 address is shifted out on the SO line. The data stored in memory at the next address can be read sequentially by continuing to provide clock pulses. The address is automatically incremented to the next higher address after each byte of data is shifted out. When the highest address is reached ($FF), the address counter rolls over to address $00, allowing the read cycle to be continued indefinitely. The read operation is terminated by taking CS HIGH. Refer to the read EEPROM array operation sequence illustrated in Figure 1. www.xicor.com Characteristics subject to change without notice. 3 of 13 X25020 To write to the status register, the WRSR instruction is followed by the data to be written. Data bits 0, 1, 4, 5, 6 and 7 must be “0”. Figure 6 illustrates this sequence. While the write is in progress following a status register or EEPROM write sequence, the status register may be read to check the WIP bit. During this time the WIP bit will be HIGH. N O FO T R RE N C EW O M D M ES EN IG D N ED S To read the status register CS line is first pulled LOW to select the device, followed by the 8-bit RDSR instruction. After the read status register opcode is sent, the contents of the status register are shifted out on the SO line. Figure 2 illustrates the read status register sequence. Write Sequence Prior to any attempt to write data into the X25020, the “write enable” latch must first be set by issuing the WREN instruction (See Figure 3). CS is first taken LOW, then the WREN instruction is clocked into the X25020. After all eight bits of the instruction are transmitted, CS must then be taken HIGH. If the user continues the write operation without taking CS HIGH after issuing the WREN instruction, the write operation will be ignored. To write data to the EEPROM memory array, the user issues the WRITE instruction, followed by the address and then the data to be written. This is minimally a thirty-two clock operation. CS must go LOW and remain LOW for the duration of the operation. The host may continue to write up to 16 bytes of data to the X25020. The only restriction is that the 16 bytes must reside on the same page. If the address counter reaches the end of the page and the clock continues, the counter will “roll over” to the first address of the page and overwrite any data that may have been written. For the write operation (byte or page write) to be completed, CS can only be brought HIGH after bit 0 of data byte N is clocked in. If it is brought HIGH at any other time, the write operation will not be completed. Refer to Figures 4 and 5 for a detailed illustration of the write sequences and time frames in which CS going HIGH are valid. Hold Operation The HOLD input should be HIGH (at VIH) under normal operation. If a data transfer is to be interrupted, HOLD can be pulled LOW to suspend the transfer until it can be resumed. The only restriction is the SCK input must be LOW when HOLD is first pulled LOW, and SCK must also be LOW when HOLD is released. The HOLD input may be tied HIGH either directly to VCC or tied to VCC through a resistor. Operational Notes The X25020 powers-up in the following state: – The device is in the low power standby state. – A HIGH to LOW transition on CS is required to enter an active state and receive an instruction. – SO pin is high impedance. – The “write enable” latch is reset. Data Protection The following circuitry has been included to prevent inadvertent writes: – The “write enable” latch is reset upon power-up. – A WREN instruction must be issued to set the “write enable” latch. – CS must come HIGH at the proper clock count in order to start a write cycle. REV 1.1 7/12/00 www.xicor.com Characteristics subject to change without notice. 4 of 13 X25020 Figure 1. Read EEPROM Array Operation Sequence CS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 N O FO T R RE N C EW O M D M ES EN IG D N ED S 0 SCK Instruction Byte Address SI 7 6 5 4 3 2 1 0 Data Out High Impedance 7 SO 6 5 4 3 2 1 0 MSB Figure 2. Read Status Register Operation Sequence CS 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 SCK Instruction SI Data Out SO High Impedance 7 6 5 4 3 2 1 0 MSB Figure 3. Write Enable Latch Sequence CS 0 1 2 3 4 5 6 7 SCK SI SO REV 1.1 7/12/00 High Impedance www.xicor.com Characteristics subject to change without notice. 5 of 13 X25020 Figure 4. Byte Write Operation Sequence CS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 N O FO T R RE N C EW O M D M ES EN IG D N ED S 0 SCK Instruction Byte Address SI 3 Data Byte 2 1 7 0 6 5 4 3 2 1 0 7 6 5 4 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 High Impedance SO Figure 5. Page Write Operation Sequence CS 0 1 2 3 4 5 6 SCK Instruction Byte Address 7 SI 6 5 4 3 Data Byte 1 2 1 0 7 6 5 4 3 2 1 0 CS 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 SCK Data Byte 2 SI REV 1.1 7/12/00 7 6 5 4 3 Data Byte 3 2 1 0 7 6 5 4 3 Data Byte 4 2 www.xicor.com 1 0 7 6 5 4 3 2 1 0 Characteristics subject to change without notice. 6 of 13 X25020 Figure 6. Write Status Register Operation Sequence CS 1 2 3 4 5 6 7 8 9 7 6 10 11 12 13 14 15 N O FO T R RE N C EW O M D M ES EN IG D N ED S 0 SCK Instruction SI SO REV 1.1 7/12/00 Data Byte 5 4 3 2 1 0 High Impedance www.xicor.com Characteristics subject to change without notice. 7 of 13 X25020 COMMENT Temperature under bias ...................–65°C to +135°C Storage temperature ........................–65°C to +150°C Voltage on any pin with respect to VSS ....... –1V to +7V D.C. output current ............................................... 5mA Lead temperature (soldering, 10 seconds).........300°C 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 listed in the operational sections of this specification) is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. N O FO T R RE N C EW O M D M ES EN IG D N ED S ABSOLUTE MAXIMUM RATINGS RECOMMENDED OPERATING CONDITIONS Temperature Min. Max. Supply Voltage Limits Commercial 0°C +70°C X25020-2.7 2.7 to 5.5V Industrial –40°C +85°C D.C. OPERATING CHARACTERISTICS (Over the recommended operating conditions unless otherwise specified.) Limits Symbol Parameter Min. Max. Unit Test Conditions ICC VCC supply current (active) 3 mA SCK = VCC x 0.1/VCC x 0.9 @ 1MHz, SO = Open ISB VCC supply current (standby) 10 µA CS = VCC, VIN = VSS or VCC – 0.3V ILI Input leakage current 10 µA VIN = VSS to VCC ILO Output leakage current 10 µA VOUT = VSS to VCC (1) Input LOW voltage –0.5 VCC x 0.3 V (1) VIH Input HIGH voltage VCC x 0.7 VCC + 0.5 V VOL Output LOW voltage 0.4 V IOL = 2mA VOH Output HIGH voltage V IOH = –1mA VIL VCC – 0.8 POWER-UP TIMING Symbol (2) (2) tPUR tPUW Parameter Min. Max. Unit Power-up to read operation 1 ms Power-up to write operation 5 ms Max. Unit Conditions Output capacitance (SO) 8 pF VOUT = 0V Input capacitance (SCK, SI, CS, WP, HOLD) 6 pF VIN = 0V CAPACITANCE TA = +25°C, F = 1MHZ, VCC = 5V. Symbol (2) COUT (2) CIN Test Notes: (1) VIL min. and VIH max. are for reference only and are not tested. (2) This parameter is periodically sampled and not 100% tested. REV 1.1 7/12/00 www.xicor.com Characteristics subject to change without notice. 8 of 13 X25020 EQUIVALENT A.C. LOAD CIRCUIT AT 5V VCC 5V Input pulse levels VCC x 0.1 to VCC x 0.9 Input rise and fall times 10ns Input and output timing level VCC x 0.5 N O FO T R RE N C EW O M D M ES EN IG D N ED S 2.16KΩ A.C. TEST CONDITIONS Output 3.07KΩ 100pF A.C. CHARACTERISTICS (Over recommended operating conditions, unless otherwise specified) Data Input Timing Symbol Parameter fSCK Clock frequency Min. Max. Unit 0 2 MHz tCYC Cycle time 1000 ns tLEAD CS lead time 500 ns tLAG CS lag time 500 ns tWH Clock HIGH time 400 ns tWL Clock LOW time 400 ns tSU Data setup time 100 ns tH Data hold time 100 ns tRI Data in rise time 2 µs tFI Data in Fall time 2 µs tHD HOLD setup time 200 ns tCD HOLD hold time 200 ns tCS CS deselect time 500 ns (4) tWC Write cycle time 10 ms Max. Unit Data Output Timing Symbol Parameter Min. fSCK Clock frequency 1 MHz tDIS Output disable time 500 ns Output valid from clock LOW 360 ns tV tHO (3) 0 Output hold time 0 ns tRO Output rise time 300 ns tFO(3) Output fall time 300 ns tLZ HOLD HIGH to output in low Z 100 ns tHZ HOLD LOW to output in high Z 100 ns Notes: (3) Parameter is tested on a sample basis only. (4) tWC is the time from the rising edge of CS after a valid write sequence has been sent to the end of the self-timed internal nonvolatile write cycle. REV 1.1 7/12/00 www.xicor.com Characteristics subject to change without notice. 9 of 13 X25020 Serial Output Timing CS tCYC tLAG N O FO T R RE N C EW O M D M ES EN IG D N ED S tWH SCK tV SO SI tHO MSB Out tWL MSB–1 Out tDIS LSB Out ADDR LSB IN Serial Input Timing tCS CS tLEAD tLAG SCK tSU SI SO REV 1.1 7/12/00 tH tRI MSB IN tFI LSB IN High Impedance www.xicor.com Characteristics subject to change without notice. 10 of 13 X25020 Hold Timing CS tHD tCD tCD N O FO T R RE N C EW O M D M ES EN IG D N ED S tHD SCK tHZ tLZ SO SI HOLD SYMBOL TABLE WAVEFORM REV 1.1 7/12/00 INPUTS OUTPUTS Must be steady Will be steady May change from LOW to HIGH Will change from LOW to HIGH May change from HIGH to LOW Will change from HIGH to LOW Don’t Care: Changes Allowed N/A Changing: State Not Known Center Line is High Impedance www.xicor.com Characteristics subject to change without notice. 11 of 13 X25020 PACKAGING INFORMATION N O FO T R RE N C EW O M D M ES EN IG D N ED S 8-Lead Plastic Small Outline Gull Wing Package Type S 0.150 (3.80) 0.228 (5.80) 0.158 (4.00) 0.244 (6.20) Pin 1 Index Pin 1 0.014 (0.35) 0.019 (0.49) 0.188 (4.78) 0.197 (5.00) (4X) 7° 0.053 (1.35) 0.069 (1.75) 0.004 (0.19) 0.010 (0.25) 0.050 (1.27) 0.010 (0.25) X 45° 0.020 (0.50) 0.050"Typical 0.050" Typical 0° - 8° 0.0075 (0.19) 0.010 (0.25) 0.250" 0.016 (0.410) 0.037 (0.937) 0.030" Typical 8 Places FOOTPRINT NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) REV 1.1 7/12/00 www.xicor.com Characteristics subject to change without notice. 12 of 13 X25020 Ordering Information X25020 P T -V VCC Limits 2.7V = 2.7V to 5.5V N O FO T R RE N C EW O M D M ES EN IG D N ED S Device Temperature Range Blank = Commercial = 0°C to +70°C I = Industrial = –40°C to +85°C Package S = 8-Lead SOIC Part Mark Convention X25020 X Blank = 8-Lead SOIC X F = 2.7V to 5.5V, 0°C to +70°C G = 2.7V to 5.5V, –40°C to +85°C LIMITED WARRANTY ©Xicor, Inc. 2000 Patents Pending Devices sold by Xicor, Inc. are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only. Xicor, Inc. makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. Xicor, Inc. makes no warranty of merchantability or fitness for any purpose. Xicor, Inc. reserves the right to discontinue production and change specifications and prices at any time and without notice. Xicor, Inc. assumes no responsibility for the use of any circuitry other than circuitry embodied in a Xicor, Inc. product. No other circuits, patents, or licenses are implied. TRADEMARK DISCLAIMER: Xicor and the Xicor logo are registered trademarks of Xicor, Inc. AutoStore, Direct Write, Block Lock, SerialFlash, MPS, and XDCP are also trademarks of Xicor, Inc. All others belong to their respective owners. U.S. PATENTS Xicor products are covered by one or more of the following U.S. Patents: 4,326,134; 4,393,481; 4,404,475; 4,450,402; 4,486,769; 4,488,060; 4,520,461; 4,533,846; 4,599,706; 4,617,652; 4,668,932; 4,752,912; 4,829,482; 4,874,967; 4,883,976; 4,980,859; 5,012,132; 5,003,197; 5,023,694; 5,084,667; 5,153,880; 5,153,691; 5,161,137; 5,219,774; 5,270,927; 5,324,676; 5,434,396; 5,544,103; 5,587,573; 5,835,409; 5,977,585. Foreign patents and additional patents pending. LIFE RELATED POLICY In situations where semiconductor component failure may endanger life, system designers using this product should design the system with appropriate error detection and correction, redundancy and back-up features to prevent such an occurrence. Xicor’s products are not authorized for use in critical components in life support devices or systems. 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. REV 1.1 7/12/00 www.xicor.com Characteristics subject to change without notice. 13 of 13