FM25V20 2Mb Serial 3V F-RAM Memory Features 2M bit Ferroelectric Nonvolatile RAM Organized as 256K x 8 bits High Endurance 100 Trillion (1014) Read/Writes 10 Year Data Retention NoDelay™ Writes Advanced High-Reliability Ferroelectric Process Very Fast Serial Peripheral Interface - SPI Up to 40 MHz Frequency Direct Hardware Replacement for Serial Flash SPI Mode 0 & 3 (CPOL, CPHA=0,0 & 1,1) Write Protection Scheme Hardware Protection Software Protection Description The FM25V20 is a 2-megabit nonvolatile memory employing an advanced ferroelectric process. A ferroelectric random access memory or F-RAM is nonvolatile and performs reads and writes like a RAM. It provides reliable data retention for 10 years while eliminating the complexities, overhead, and system level reliability problems caused by Serial Flash and other nonvolatile memories. Device ID Device ID reads out Manufacturer ID & Part ID Low Voltage, Low Power Low Voltage Operation 2.0V – 3.6V 100 A Standby Current (typ.) 3 A Sleep Mode Current (typ.) Industry Standard Configurations Industrial Temperature -40C to +85C 8-pin “Green”/RoHS EIAJ SOIC Package 8-pin “Green”/RoHS TDFN Package 8-pin “Green”/POHS PDIP Package Device ID that allows the host to determine the manufacturer, product density, and product revision. The device is guaranteed over an industrial temperature range of -40°C to +85°C. Pin Configuration Top View Unlike Serial Flash, the FM25V20 performs write operations at bus speed. No write delays are incurred. Data is written to the memory array immediately after it has been transferred to the device. The next bus cycle may commence without the need for data polling. The product offers very high write endurance, orders of magnitude more endurance than Serial Flash. Also, F-RAM exhibits lower power consumption than Serial Flash. These capabilities make the FM25V20 ideal for nonvolatile memory applications requiring frequent or rapid writes or low power operation. Examples range from data collection, where the number of write cycles may be critical, to demanding controls where the long write time of Serial Flash can cause data loss. The FM25V20 provides substantial benefits to users of Serial Flash as a hardware drop-in replacement. The device uses the high-speed SPI bus, which enhances the high-speed write capability of F-RAM technology. The device incorporates a read-only This product conforms to specifications per the terms of the Ramtron standard warranty. The product has completed Ramtron’s internal qualification testing and has reached production status. Rev. 3.0 August 2012 /S 1 8 VDD Q 2 7 /HOLD /W 3 6 C VSS 4 5 D S 1 8 VDD Q 2 7 HOLD W 3 6 C VSS 4 5 D Pin Name Function /S /W /HOLD C D Q VDD VSS Chip Select Write Protect Hold Serial Clock Serial Data Input Serial Data Output Supply Voltage Ground Ramtron International Corporation 1850 Ramtron Drive, Colorado Springs, CO 80921 (800) 545-FRAM, (719) 481-7000 http://www.ramtron.com Page 1 of 17 FM25V20 – 2Mb SPI F-RAM W S Instruction Decode Clock Generator Control Logic Write Protect HOLD C 32K x 64 FRAM Array Instruction Register Address Register Counter D 18 8 Data I/O Register Q 3 Nonvolatile Status Register Figure 1. Block Diagram Pin Descriptions Pin Name /S I/O Input C Input /HOLD Input /W Input D Input Q Output VDD VSS Supply Supply Rev. 3.0 August 2012 Description Chip Select: This active-low input activates the device. When high, the device enters low-power standby mode, ignores other inputs, and all outputs are tri-stated. When low, the device internally activates the C signal. A falling edge on /S must occur prior to every op-code. Serial Clock: All I/O activity is synchronized to the serial clock. Inputs are latched on the rising edge and outputs occur on the falling edge. Since the device is static, the clock frequency may be any value between 0 and 40 MHz and may be interrupted at any time. Hold: The /HOLD pin is used when the host CPU must interrupt a memory operation for another task. When /HOLD is low, the current operation is suspended. The device ignores any transition on C or /S. All transitions on /HOLD must occur while C is low. If it is not used, the /HOLD pin should be tied to VDD. Write Protect: This active-low pin prevents write operations to the Status Register only. A complete explanation of write protection is provided on pages 6 and 7. If it is not used, the /W pin should be tied to VDD. Serial Input: All data is input to the device on this pin. The pin is sampled on the rising edge of C and is ignored at other times. It should always be driven to a valid logic level to meet IDD specifications. * D may be connected to Q for a single pin data interface. Serial Output: This is the data output pin. It is driven during a read and remains tristated at all other times including when /HOLD is low. Data transitions are driven on the falling edge of the serial clock. * Q may be connected to D for a single pin data interface. Power Supply Ground Page 2 of 17 FM25V20 – 2Mb SPI F-RAM Overview The FM25V20 is a serial F-RAM memory. The memory array is logically organized as 262,144 x 8 and is accessed using an industry standard Serial Peripheral Interface or SPI bus. Functional operation of the F-RAM is similar to Serial Flash. The major differences between the FM25V20 and a Serial Flash with the same pinout are the F-RAM’s superior write performance, very high endurance, and lower power consumption. Memory Architecture When accessing the FM25V20, the user addresses 256K locations of 8 data bits each. These data bits are shifted serially. The addresses are accessed using the SPI protocol, which includes a chip select (to permit multiple devices on the bus), an op-code, and a threebyte address. The complete address of 18-bits specifies each byte address uniquely. Most functions of the FM25V20 either are controlled by the SPI interface or are handled automatically by on-board circuitry. The access time for memory operation is essentially zero, beyond the time needed for the serial protocol. That is, the memory is read or written at the speed of the SPI bus. Unlike Serial Flash, it is not necessary to poll the device for a ready condition since writes occur at bus speed. So, by the time a new bus transaction can be shifted into the device, a write operation will be complete. This is explained in more detail in the interface section. Users expect several obvious system benefits from the FM25V20 due to its fast write cycle and high endurance as compared to Serial Flash. In addition there are less obvious benefits as well. For example in a high noise environment, the fast-write operation is less susceptible to corruption than Serial Flash since it is completed quickly. By contrast, Serial Flash requiring milliseconds to write is vulnerable to noise during much of the cycle. Serial Peripheral Interface – SPI Bus The FM25V20 employs a Serial Peripheral Interface (SPI) bus. It is specified to operate at speeds up to 40MHz. This high-speed serial bus provides high performance serial communication to a host microcontroller. Many common microcontrollers have hardware SPI ports allowing a direct interface. It is quite simple to emulate the port using ordinary port pins for microcontrollers that do not. The FM25V20 operates in SPI Mode 0 and 3. Protocol Overview The SPI interface is a synchronous serial interface using clock and data pins. It is intended to support multiple devices on the bus. Each device is activated using a chip select. Once chip select is activated by the bus master, the FM25V20 will begin monitoring the clock and data lines. The relationship between the falling edge of /S, the clock and data is dictated by the SPI mode. The device will make a determination of the SPI mode on the falling edge of each chip select. While there are four such modes, the FM25V20 supports only modes 0 and 3. Figure 2 shows the required signal relationships for modes 0 and 3. For both modes, data is clocked into the FM25V20 on the rising edge of C and data is expected on the first rising edge after /S goes active. If the clock starts from a high state, it will fall prior to the first data transfer in order to create the first rising edge. The SPI protocol is controlled by op-codes. These op-codes specify the commands to the device. After /S is activated the first byte transferred from the bus master is the op-code. Following the op-code, any addresses and data are then transferred. Certain op-codes are commands with no subsequent data transfer. The /S must go inactive after an operation is complete and before a new op-code can be issued. There is one valid op-code only per active chip select. SPI Mode 0: CPOL=0, CPHA=0 S C D 7 6 5 4 3 2 1 MSB 0 LSB SPI Mode 3: CPOL=1, CPHA=1 S C D 7 MSB 6 5 4 3 2 1 0 LSB Figure 2. SPI Modes 0 & 3 Rev. 3.0 August 2012 Page 3 of 17 FM25V20 – 2Mb SPI F-RAM System Hookup The SPI interface uses a total of four pins: clock, data-in, data-out, and chip select. A typical system configuration uses one or more FM25V20 devices with a microcontroller that has a dedicated SPI port, as Figure 3 illustrates. Note that the clock, data-in, and data-out pins are common among all devices. The Chip Select and Hold pins must be driven separately for each FM25V20 device. For a microcontroller that has no dedicated SPI bus, a general purpose port may be used. To reduce hardware resources on the controller, it is possible to connect the two data pins together and tie off the Hold pin. Figure 4 shows a configuration that uses only three pins. SCK MOSI MISO Q SPI Microcontroller D C Q D C FM25V20 FM25V20 S S HOLD HOLD SS1 SS2 HOLD1 HOLD2 MOSI : Master Out Slave In MISO : Master In Slave Out SS : Slave Select Figure 3. 4Mbit (512KB) System Configuration with SPI port P1.0 P1.1 Q Microcontroller D C FM25V20 S HOLD VDD P1.2 Figure 4. System Configuration without SPI port Rev. 3.0 August 2012 Page 4 of 17 FM25V20 – 2Mb SPI F-RAM Power Up to First Access The FM25V20 is not accessible for a period of time (tPU) after power up. Users must comply with the timing parameter tPU, which is the minimum time from VDD (min) to the first /S low. Data Transfer All data transfers to and from the FM25V20 occur in 8-bit groups. They are synchronized to the clock signal (C), and they transfer most significant bit (MSB) first. Serial inputs are registered on the rising edge of C. Outputs are driven from the falling edge of clock C. Command Structure There are nine commands called op-codes that can be issued by the bus master to the FM25V20. They are listed in the table below. These op-codes control the functions performed by the memory. They can be divided into three categories. First, there are commands that have no subsequent operations. They perform a single function, such as to enable a write operation. Second are commands followed by one byte, either in or out. They operate on the Status Register. The third group includes commands for memory transactions followed by address and one or more bytes of data. Table 1. Op-code Commands Name Description Set Write Enable Latch WREN Write Disable WRDI Read Status Register RDSR Write Status Register WRSR Read Memory Data READ FSTRD Fast Read Memory Data WRITE Write Memory Data Enter Sleep Mode SLEEP Read Device ID RDID without another WREN command. Figure 5 below illustrates the WREN command bus configuration. S 0 1 2 3 4 5 6 7 0 0 0 0 0 1 1 0 C D Hi-Z Q Figure 5. WREN Bus Configuration WRDI – Write Disable The WRDI command disables all write activity by clearing the Write Enable Latch. The user can verify that writes are disabled by reading the WEL bit in the Status Register and verifying that WEL=0. Figure 6 illustrates the WRDI command bus configuration. S 0 1 2 3 4 5 6 7 0 0 0 0 0 1 0 0 C Op-code 0000 0000 0000 0000 0000 0000 0000 1011 1001 0110b 0100b 0101b 0001b 0011b 1011b 0010b 1001b 1111b WREN – Set Write Enable Latch The FM25V20 will power up with writes disabled. The WREN command must be issued prior to any write operation. Sending the WREN op-code will allow the user to issue subsequent op-codes for write operations. These include writing the Status Register (WRSR) and writing the memory (WRITE). D Q Hi-Z Figure 6. WRDI Bus Configuration RDSR – Read Status Register The RDSR command allows the bus master to verify the contents of the Status Register. Reading Status provides information about the current state of the write protection features. Following the RDSR op-code, the FM25V20 will return one byte with the contents of the Status Register. The Status Register is described in detail in the section below. Sending the WREN op-code causes the internal Write Enable Latch to be set. A flag bit in the Status Register, called WEL, indicates the state of the latch. WEL=1 indicates that writes are permitted. Attempting to write the WEL bit in the Status Register has no effect on the state of this bit. Completing any write operation will automatically clear the write-enable latch and prevent further writes Rev. 3.0 August 2012 Page 5 of 17 FM25V20 – 2Mb SPI F-RAM WRSR – Write Status Register The WRSR command allows the user to select certain write protection features by writing a byte to the Status Register. Prior to issuing a WRSR command, the /W pin must be high or inactive. Prior to sending the WRSR command, the user must send a WREN command to enable writes. Note that executing a WRSR command is a write operation and therefore clears the Write Enable Latch. The bus configuration of RDSR and WRSR are shown below. S C D Q Figure 7. RDSR Bus Configuration S C D Q Figure 8. WRSR Bus Configuration Status Register & Write Protection The write protection features of the FM25V20 are multi-tiered. Taking the /W pin to a logic low state is the hardware write-protect function. Status Register write operations are blocked when /W is low. To write the memory with /W high, a WREN op-code must first be issued. Assuming that writes are enabled using WREN and by /W, writes to memory are controlled by the Status Register. As described above, writes to the Status Register are performed using the WRSR command and subject to the /W pin. The Status Register is organized as follows. Table 2. Status Register Bit Name 7 WPEN 6 1 5 0 4 0 3 BP1 2 BP0 1 WEL 0 0 Bits 0, 4, 5 are fixed at 0 and bit 6 is fixed at 1, and none of these bits can be modified. Note that bit 0 (“Ready” in Serial Flash) is unnecessary as the FRAM writes in real-time and is never busy, so it reads out as a ‘0’. There is an exception to this when the device is waking up from Sleep Mode, which is described in the Sleep Mode section. The BP1 and BP0 control software write protection features. They are nonvolatile (shaded yellow). The WEL flag indicates the state of the Write Enable Latch. Attempting to directly write the WEL bit in the Status Rev. 3.0 August 2012 Register has no effect on its state. This bit is internally set and cleared via the WREN and WRDI commands, respectively. BP1 and BP0 are memory block write protection bits. They specify portions of memory that are writeprotected as shown in the following table. Table 3. Block Memory Write Protection BP1 BP0 Protected Address Range 0 0 None 0 1 30000h to 3FFFFh (upper ¼) 1 0 20000h to 3FFFFh (upper ½) 1 1 00000h to 3FFFFh (all) The BP1 and BP0 bits and the Write Enable Latch are the only mechanisms that protect the memory from writes. The remaining write protection features protect inadvertent changes to the block protect bits. The WPEN bit controls the effect of the hardware /W pin. When WPEN is low, the /W pin is ignored. When WPEN is high, the /W pin controls write access to the Status Register. Thus the Status Register is write protected if WPEN=1 and /W=0. This scheme provides a write protection mechanism, which can prevent software from writing the memory Page 6 of 17 FM25V20 – 2Mb SPI F-RAM under any circumstances. This occurs if the BP1 and BP0 bits are set to 1, the WPEN bit is set to 1, and the /W pin is low. This occurs because the block protect bits prevent writing memory and the /W signal in hardware prevents altering the block protect Table 4. Write Protection WEL WPEN 0 X 1 0 1 1 1 1 /W X X 0 1 Protected Blocks Protected Protected Protected Protected Memory Operation The SPI interface, which is capable of a relatively high clock frequency, highlights the fast write capability of the F-RAM technology. Unlike Serial Flash, the FM25V20 can perform sequential writes at bus speed. No page buffer is needed and any number of sequential writes may be performed. Write Operation All writes to the memory array begin with a WREN op-code. The next op-code is the WRITE instruction. This op-code is followed by a three-byte address value, which specifies the 18-bit address of the first data byte of the write operation. Subsequent bytes are data and they are written sequentially. Addresses are incremented internally as long as the bus master continues to issue clocks. If the last address of 3FFFFh is reached, the counter will roll over to 00000h. Data is written MSB first. A write operation is shown in Figure 9. Unlike Serial Flash, any number of bytes can be written sequentially and each byte is written to memory immediately after it is clocked in (after the 8th clock). The rising edge of /S terminates a WRITE op-code operation. Asserting /W active in the middle of a write operation will have no effect until the next falling edge of /S. Read Operation After the falling edge of /S, the bus master can issue a READ op-code. Following this instruction is a three-byte address value (A17-A0), specifying the address of the first data byte of the read operation. After the op-code and address are complete, the D pin is ignored. The bus master issues 8 clocks, with Rev. 3.0 August 2012 bits (if WPEN is high). Therefore in this condition, hardware must be involved in allowing a write operation. The following table summarizes the write protection conditions. Unprotected Blocks Protected Unprotected Unprotected Unprotected Status Register Protected Unprotected Protected Unprotected one bit read out for each. Addresses are incremented internally as long as the bus master continues to issue clocks. If the last address of 3FFFFh is reached, the counter will roll over to 00000h. Data is read MSB first. The rising edge of /S terminates a READ opcode operation and tri-states the Q pin. A read operation is shown in Figure 10. Fast Read Operation The FM25V20 supports the FAST READ op-code (0Bh) that is found on Serial Flash devices. It is implemented for code compatibility with Serial Flash devices. Following this instruction is a three-byte address (A17-A0), specifying the address of the first data byte of the read operation. A dummy address byte follows the address. It inserts one byte of read latency. The D pin is ignored after the op-code, threebyte address, and dummy byte are complete. The bus master issues 8 clocks, with one bit read out for each. The Fast Read operation is otherwise the same as an ordinary READ. If the last address of 3FFFFh is reached, the counter will roll over to 00000h. Data is read MSB first. The rising edge of /S terminates a FAST READ op-code operation and tri-states the Q pin. A Fast Read operation is shown in Figure 11. Hold The FM25V20 device has a /HOLD pin that can be used to interrupt a serial operation without aborting it. If the bus master pulls the /HOLD pin low while C is low, the current operation will pause. Taking the /HOLD pin high while C is low will resume an operation. The transitions of /HOLD must occur while C is low, but the C and /S pins can toggle during a hold state. Page 7 of 17 FM25V20 – 2Mb SPI F-RAM S 0 1 2 3 4 5 6 7 0 1 2 0 0 0 3 4 5 6 7 4 5 6 7 0 1 2 3 4 5 6 7 A3 A2 A1 A0 7 6 Data 5 4 3 2 1 0 C op-code D 0 0 0 0 0 18-bit Add ress 0 1 0 0 0 0 A17 A16 MSB LSB MSB LSB Q Figure 9. Memory Write with 3-Byte Address S 0 1 2 3 4 5 6 7 0 1 2 0 0 0 3 4 5 6 7 4 5 6 7 0 1 2 7 6 5 0 1 2 6 5 3 4 5 6 7 4 3 2 1 0 3 4 5 6 7 3 2 1 C 18-bit Address op-code D 0 0 0 0 0 0 1 1 0 0 0 A17 A16 A3 A2 A1 A0 MSB LSB Q Data MSB LSB Figure 10. Memory Read with 3-Byte Address S 0 1 2 3 4 5 6 7 0 1 2 0 0 0 3 5 6 7 4 5 6 7 C op-code D 0 0 0 0 1 1 1 MSB Q Dummy byte 18-bit Address 0 0 A2 A1 A0 LSB X X X X Data MSB 7 4 LSB 0 Figure 11. Fast Read with 3-Byte Address and Dummy Byte Rev. 3.0 August 2012 Page 8 of 17 FM25V20 – 2Mb SPI F-RAM Sleep Mode A low power mode called Sleep Mode is implemented on the FM25V20 device. The device will enter this low power state when the SLEEP opcode B9h is clocked-in and a rising edge of /S is applied. Once in sleep mode, the C and D pins are ignored and Q will be high-Z, but the device continues to monitor the /S pin. On the next falling edge of /S, the device will return to normal operation within tREC (400 s max.). The Q pin remains in a hiZ state during the wakeup period. The device will not necessarily respond to an opcode within the wakeup period. To start the wakeup procedure, the controller may send a “dummy” read, for example, and wait the remaining tREC time. Enter Sleep Mode S C D Q Figure 12. Sleep Mode Entry Device ID The FM25V20 device can be interrogated for its manufacturer, product identification, and die revision. The RDID op-code 9Fh allows the user to read the manufacturer ID and product ID, both of which are read-only bytes. The JEDEC-assigned manufacturer ID places the Ramtron identifier in bank 7, therefore there are six bytes of the continuation code 7Fh followed by the single byte C2h. There are two bytes of product ID, which includes a Family code, a Density code, a Sub code, and Product Revision code. Table 5. Manufacturer and Product ID Manufacturer ID Device ID (1st Byte) Device ID (2nd Byte) 7 0 0 0 0 0 0 1 6 1 1 1 1 1 1 1 5 1 1 1 1 1 1 0 Bit 4 3 1 1 1 1 1 1 1 1 1 1 1 1 0 0 2 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 0 Hex 7F 7F 7F 7F 7F 7F C2 Continuation code Continuation code Continuation code Continuation code Continuation code Continuation code JEDEC assigned Ramtron C2h in bank 7 Family Density 0 0 1 0 0 1 0 1 Sub Rev. Rsvd 0 0 0 0 0 0 0 0 Hex 25h Density: 03h=512K, 04h=1M, 05h=2M, 06h=4M 00h 00h=FM25V20 7Fh C2h S ....... C D Q 9Fh 7Fh … 1 25h 00h 6 Six bytes of continuation code 7Fh Figure 13. Read Device ID Rev. 3.0 August 2012 Page 9 of 17 FM25V20 - 2Mb SPI F-RAM Endurance The FM25V20 device is capable of being accessed at least 1014 times, reads or writes. An F-RAM memory operates with a read and restore mechanism. Therefore, an endurance cycle is applied on a row basis for each access (read or write) to the memory array. The F-RAM architecture is based on an array of rows and columns. Rows are defined by A17-A3 and column addresses by A2-A0. See Block Diagram (pg 2) which shows the array as 32K rows of 64-bits each. The entire row is internally accessed once whether a single byte or all eight bytes are read or written. Each byte in the row is counted only once in an endurance calculation. The table below shows endurance calculations for 64-byte repeating loop, which includes an op-code, a starting address, and a sequential 64-byte data stream. This causes each byte to experience one endurance cycle through the loop. F-RAM read and write endurance is virtually unlimited even at 40MHz clock rate. Table 6. Time to Reach 100 Trillion Cycles for Repeating 64-byte Loop SCK Freq Endurance Endurance Years to Reach (MHz) Cycles/sec. Cycles/year 1014 Cycles 12 43.1 40 73,520 2.32 x 10 10 18,380 5.79 x 1011 172.7 5 9,190 2.90 x 1011 345.4 Rev. 3.0 August 2012 Page 10 of 17 FM25V20 - 2Mb SPI F-RAM Electrical Specifications Absolute Maximum Ratings Symbol Description VDD Power Supply Voltage with respect to VSS VIN Voltage on any pin with respect to VSS TSTG TLEAD VESD Storage Temperature Lead Temperature (Soldering, 10 seconds) Electrostatic Discharge Voltage - Human Body Model (JEDEC Std JESD22-A114-B) - Charged Device Model (JEDEC Std JESD22-C101-A) - Machine Model (JEDEC Std JESD22-A115-A) Package Moisture Sensitivity Level Ratings -1.0V to +4.5V -1.0V to +4.5V and VIN < VDD+1.0V -55C to + 125C 260 C 4kV 1.25kV 250V MSL-1 Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only, and the functional operation of the device at these or any other conditions above those listed in the operational section of this specification is not implied. Exposure to absolute maximum ratings conditions for extended periods may affect device reliability. DC Operating Conditions (TA = -40C to + 85C, VDD = 2.0V to 3.6V unless otherwise specified) Symbol Parameter Min Typ Max Units VDD Power Supply Voltage 2.0 3.3 3.6 V IDD Power Supply Operating Current @ C = 1 MHz 0.13 0.30 mA @ C = 40 MHz 1.4 3.0 mA ISB Standby Current A @ TA = 25°C 100 150 A @ TA = 85°C 250 IZZ Sleep Mode Current A @ TA = 25°C 3 5 A @ TA = 85°C 8 ILI Input Leakage Current A 1 ILO Output Leakage Current A 1 VIH Input High Voltage 0.7 VDD VDD + 0.3 V VIL Input Low Voltage -0.3 0.3 VDD V VOH1 Output High Voltage (IOH = -1 mA, VDD=2.7V) 2.4 V VOH2 Output High Voltage (IOH = -100 A) VDD-0.2 V VOL1 Output Low Voltage (IOL = 2 mA, VDD=2.7V) 0.4 V VOL2 Output Low Voltage (IOL = 150 A) 0.2 V Notes 1. C toggling between VDD-0.2V and VSS, other inputs VSS or VDD-0.2V. Q=open. 2. /S=VDD. All inputs VSS or VDD. 3. In Sleep mode and /S=VDD. All inputs VSS or VDD. 4. VSS VIN VDD and VSS VOUT VDD. Data Retention (TA = -40C to + 85C) Symbol Parameter TDR Data Retention Rev. 3.0 August 2012 Min 10 Max - Units Years Notes 1 2 3 4 4 Notes Page 11 of 17 FM25V20 – 2Mb SPI F-RAM AC Parameters (TA = -40C to + 85C, CL = 30pF, unless otherwise specified) VDD 2.0 to 2.7V VDD 2.7 to 3.6V Symbol Parameter Min Max Min Max fCK C Clock Frequency 0 25 0 40 tCH Clock High Time 20 11 tCL Clock Low Time 20 11 tCSU Chip Select Setup 12 10 tCSH Chip Select Hold 12 10 tOD Output Disable Time 20 12 tODV Output Data Valid Time 18 9 tOH Output Hold Time 0 0 tD Deselect Time 60 40 tR Data In Rise Time 50 50 tF Data In Fall Time 50 50 tSU Data Setup Time 8 5 tH Data Hold Time 8 5 tHS /HOLD Setup Time 12 10 tHH /HOLD Hold Time 12 10 tHZ /HOLD Low to Hi-Z 25 20 tLZ /HOLD High to Data Active 25 20 Notes 1. 2. 3. 4. Units MHz ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns Notes 1 1 3 3 2,4 2,4 3 4 4 tCH + tCL = 1/fCK. Rise and fall times measured between 10% and 90% of waveform. Guaranteed by design. Guaranteed by design for 1MHz fCK. Capacitance (TA = 25 C, f=1.0 MHz, VDD = 3.3V) Symbol Parameter CO Output Capacitance (Q) CI Input Capacitance Notes 1. Guaranteed by design. AC Test Conditions Input Pulse Levels Input rise and fall times Input and output timing levels Output Load Capacitance Min - Max 8 6 Units pF pF Notes 1 1 10% and 90% of VDD 3 ns 50% of VDD 30 pF Serial Data Bus Timing tD S tCSU C tSU tF 1/tCK tR tCL tCH tCSH tH D tODV tOH tOD Q /HOLD Timing Rev. 3.0 August 2012 Page 12 of 17 FM25V20 – 2Mb SPI F-RAM tHS S tHH C tHH tHS HOLD Q tHZ tLZ Power Cycle Timing VDD VDD min. tVR tVF tPU tPD S Power Cycle & Sleep Timing (TA = -40 C to + 85 C, VDD = 2.0V to 3.6V, unless otherwise specified) Symbol Parameter Min Max Units Notes tVR VDD Rise Time 50 s/V 1 tVF VDD Fall Time 100 s/V 1 tPU Power Up (VDD min) to First Access (/S low) 1 ms tPD Last Access (/S high) to Power Down (VDD min) 0 s 2 tREC Recovery Time from Sleep Mode 450 s Notes 1. Slope measured at any point on VDD waveform. 2. Guaranteed by design. Rev. 3.0 August 2012 Page 13 of 17 FM25V20 – 2Mb SPI F-RAM Mechanical Drawing 8-pin TDFN* (5.0 mm x 6.0 mm body, 1.27 mm pad pitch) Exposed metal pad should be left floating. 6.0 BSC 5.0 BSC Pin 1 ID Pin 1 0.60 ±0.05 3.81 REF 0.0 - 0.05 0.75 ±0.05 0.20 REF. Recommended PCB Footprint 1.27 0.40 ±0.05 1.4 6.80 Silkscreen Pin 1 1.27 0.60 Note: All dimensions in millimeters. This package is footprint compatible with the 8-pin SOIC. The exposed pad should be left floating. TDFN Package Marking Scheme for Body Size 5.0mm x 6.0mm RGXXXXT LLLL YYWW Legend: R=Ramtron, G=”green” TDFN package XXXX=base part number, T=temperature (blank=ind., C=comm.) LLLL= lot code YY=year, WW=work week Example: “Green” TDFN package, FM25V20, Lot 0012, Year 2010, Work Week 29 RG5V20 0012 1029 Rev. 3.0 August 2012 Page 14 of 17 FM25V20 – 2Mb SPI F-RAM Mechanical Drawing 8-pin DIP* JEDEC MS-001 0.280 max 0.240 min Index Area 0.325 max 0.300 min 0.400 max 0.355 min 0.195 max 0.210 0.115 min max 0.015 min 0.005 min 0.100 BSC 0.022 max 0.014 min 0.300 nom 0.430 max Refer to JEDEC MS-001 for complete dimensions and notes. Controlling dimensions in inches. PDIP Package Marking Scheme XXXXX-PT RLLLLLLL RICYYWW Legend: XXXXX= part number, P=Package (P=PDIP “Green”), T=Temp. Range (C=commercial, <blank>=industrial) R=rev code, LLLLLLL= lot code RIC=Ramtron Int’l Corp, YY=year, WW=work week Example: FM25H20, “Green”/RoHS PDIP package, Rev. A, Lot 0448727, Year 2011, Work Week 03 25H20-P A0448727 RIC1103 Rev. 3.0 August 2012 Page 15 of 17 FM25V20 – 2Mb SPI F-RAM 8-pin EIAJ SOIC Recommended PCB Footprint 9.30 5.28 ±0.10 5.00 8.00 ±0.25 2.15 0.65 1.27 Pin 1 5.23 ±0.10 1.27 0.36 0.50 1.78 2.00 0.05 0.25 0.19 0.25 0.10 mm 0- 8 0.51 0.76 All dimensions in millimeters. EIAJ SOIC Package Marking Scheme XXXXXXX-PT RLLLLLLL RIC YYWW Legend: XXXXXX= part number, P=package (G=”Green”), T=temp (blank=ind., C=comm.) R=rev code, LLLLLLL= lot code RIC=Ramtron Int’l Corp, YY=year, WW=work week Example: FM25V20, “Green”/RoHS EIAJ SOIC package, Rev A, Lot 0448727, Year 2010, Work Week 29 FM25V20-G A0448727 RIC 1029 Rev. 3.0 August 2012 Page 16 of 17 FM25V20 – 2Mb SPI F-RAM Revision History Revision 1.0 1.1 1.2 2.0 3.0 Date 6/15/2010 8/8/2011 11/21/2011 12/20/2011 08/13/2012 Summary Initial release. Removed S/N options. Added ESD ratings. Changed to Pre-Production status. Changed tPU and tREC specs. Changed to Production status. Parameters tOD, tOH, tR, tF, tHH, tHZ & tLZ changed to “Guaranteed by Design”. Added PDIP package. Note: Packages marked * are under package vendor re-qualification. Ordering Information Part Number Features FM25V20-G FM25V20-DG FM25V20-PG FM25V20-GTR FM25V20-DGTR Rev. 3.0 August 2012 Device ID Device ID Device ID Device ID Operating Voltage 2.0-3.6V 2.0-3.6V 2.0-3.6V 2.0-3.6V Operating Temp. -40C to +85C -40C to +85C -40C to +85C -40C to +85C Device ID 2.0-3.6V -40C to +85C Package 8-pin “Green”/RoHS EIAJ 8-pin “Green”/RoHS TDFN* 8-pin “Green”/RoHS PDIP* 8-pin “Green”/RoHS EIAJ, Tape & Reel 8-pin “Green”/RoHS TDFN, Tape & Reel Page 17 of 17