FM24V01-G

FM24V01 128Kb Serial 3V F-RAM Memory Features 128K bit Ferroelectric Nonvolatile RAM  Organized as 16,384 x 8 bits  High Endurance 100 Trillion (1014) Read/Writes  10 year Data Retention  NoDelay™ Writes  Advanced High-Reliability Ferroelectric Process Fast Two-wire Serial Interface  Up to 3.4 MHz maximum bus frequency  Direct hardware replacement for EEPROM  Supports legacy timing for 100 kHz & 400 kHz Description The FM24V01 is a 128Kbit 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 EEPROM and other nonvolatile memories. The FM24V01 performs write operations at bus speed. No write delays are incurred. The next bus cycle may commence immediately without the need for data polling. In addition, the product offers write endurance orders of magnitude higher than EEPROM. Also, F-RAM exhibits much lower power during writes than EEPROM since write operations do not require an internally elevated power supply voltage for write circuits. These capabilities make the FM24V01 ideal for nonvolatile memory applications requiring frequent or rapid writes. Examples range from data collection where the number of write cycles may be critical, to demanding industrial controls where the long write time of EEPROM can cause data loss. The combination of features allows more frequent data writing with less overhead for the system. Device ID  Device ID reads out Manufacturer ID & Part ID Low Voltage, Low Power Operation  Low Voltage Operation 2.0V – 3.6V  Active Current 90 A (typ. @ 100KHz)  Standby Current 80 A (typ.)  Sleep Mode Current 4 A (typ.) Industry Standard Configuration  Industrial Temperature -40 C to +85 C  8-pin “Green”/RoHS SOIC Package a hardware drop-in replacement. The device is available in an industry standard 8-pin SOIC package using a familiar two-wire (I2C) protocol. The device incorporates a read-only 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 A0 A1 A2 1 8 VDD 2 7 3 6 VSS 4 5 WP SCL SDA Pin Name A0-A2 SDA SCL WP VDD VSS Function Device Select Address Serial Data/address Serial Clock Write Protect Supply Voltage Ground The FM24V01 provides substantial benefits to users of serial EEPROM, yet these benefits are available in 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 Jan. 2012 Ramtron International Corporation 1850 Ramtron Drive, Colorado Springs, CO 80921 (800) 545-FRAM, (719) 481-7000 http://www.ramtron.com Page 1 of 14 FM24V01 - 128Kb I2C FRAM Counter Address Latch 2K x 64 FRAM Array 8 SDA Serial to Parallel Converter Data Latch 8 SCL WP Control Logic A0-A2 Device ID and Serial Number Figure 1. FM24V01 Block Diagram Pin Description Pin Name A0-A2 Type Input SDA I/O SCL Input WP Input VDD VSS Rev. 3.0 Jan. 2012 Supply Supply Pin Description Device Select Address 0-2: These pins are used to select one of up to 8 devices of the same type on the same two-wire bus. To select the device, the address value on the two pins must match the corresponding bits contained in the slave address. The address pins are pulled down internally. Serial Data/Address: This is a bi-directional pin for the two-wire interface. It is open-drain and is intended to be wire-OR’d with other devices on the two-wire bus. The input buffer incorporates a Schmitt trigger for noise immunity and the output driver includes slope control for falling edges. An external pull-up resistor is required. Serial Clock: The serial clock pin for the two-wire interface. Data is clocked out of the part on the falling edge, and into the device on the rising edge. The SCL input also incorporates a Schmitt trigger input for noise immunity. Write Protect: When tied to VDD, addresses in the entire memory map will be writeprotected. When WP is connected to ground, all addresses may be written. This pin is pulled down internally. Supply Voltage Ground Page 2 of 14 FM24V01 - 128Kb I2C FRAM Overview Two-wire Interface The FM24V01 is a serial F-RAM memory device. The memory array is logically organized as a 16,384 x 8 bit memory array and is accessed using an industry standard two-wire (I2C) interface. Functional operation of the F-RAM is similar to serial EEPROM. The major difference between the FM24V01 and serial EEPROM is F-RAM’s superior write performance. The FM24V01 employs a bi-directional two-wire bus protocol using few pins or board space. Figure 2 illustrates a typical system configuration using the FM24V01 in a microcontroller-based system. The industry standard two-wire bus is familiar to many users but is described in this section. Memory Architecture When accessing the FM24V01, the user addresses 16,384 locations each with 8 data bits. These data bits are shifted serially. The 16,384 addresses are accessed using the two-wire protocol, which includes a slave address (to distinguish other non-memory devices) and a 2-byte address. All 14 address bits are used by the decoder for accessing the memory. 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 two-wire bus. Unlike an EEPROM, it is not necessary to poll the device for a ready condition since writes occur at bus speed. That is, by the time a new bus transaction can be shifted into the part, a write operation will be complete. This is explained in more detail in the interface section below. Users expect several obvious system benefits from the FM24V01 due to its fast write cycle and high endurance as compared with EEPROM. However there are less obvious benefits as well. For example in a high noise environment, the fast-write operation is less susceptible to corruption than an EEPROM since it is completed quickly. By contrast, an EEPROM requiring milliseconds to write is vulnerable to noise during much of the cycle. By convention, any device that is sending data onto the bus is the transmitter while the target device for this data is the receiver. The device that is controlling the bus is the master. The master is responsible for generating the clock signal for all operations. Any device on the bus that is being controlled is a slave. The FM24V01 always is a slave device. The bus protocol is controlled by transition states in the SDA and SCL signals. There are four conditions including start, stop, data bit, or acknowledge. Figure 3 illustrates the signal conditions that specify the four states. Detailed timing diagrams are shown in the electrical specifications section. VDD Rmin = 1.1 Kohm Rmax = tR/Cbus Microcontroller SDA SCL FM24V01 A0 A1 A2 SDA SCL FM24V01 A0 A1 A2 Figure 2. Typical System Configuration Note that it is the user’s responsibility to ensure that VDD is within datasheet tolerances to prevent incorrect operation. Rev. 3.0 Jan. 2012 Page 3 of 14 FM24V01 - 128Kb I2C FRAM SCL SDA 7 Stop (Master) Start (Master) 6 Data bits (Transmitter) 0 Data bit Acknowledge (Transmitter) (Receiver) Figure 3. Data Transfer Protocol Stop Condition A stop condition is indicated when the bus master drives SDA from low to high while the SCL signal is high. All operations using the FM24V01 should end with a stop condition. If an operation is in progress when a stop is asserted, the operation will be aborted. The master must have control of SDA (not a memory read) in order to assert a stop condition. Start Condition A start condition is indicated when the bus master drives SDA from high to low while the SCL signal is high. All commands should be preceded by a start condition. An operation in progress can be aborted by asserting a start condition at any time. Aborting an operation using the start condition will ready the FM24V01 for a new operation. If during operation the power supply drops below the specified VDD minimum, the system should issue a start condition prior to performing another operation. Data/Address Transfer All data transfers (including addresses) take place while the SCL signal is high. Except under the two conditions described above, the SDA signal should not change while SCL is high. Acknowledge The acknowledge takes place after the 8th data bit has been transferred in any transaction. During this state the transmitter should release the SDA bus to allow the receiver to drive it. The receiver drives the SDA signal low to acknowledge receipt of the byte. If the receiver does not drive SDA low, the condition is a no-acknowledge and the operation is aborted. The receiver would fail to acknowledge for two distinct reasons. First is that a byte transfer fails. In this case, the no-acknowledge ceases the current operation so that the part can be addressed again. This allows the last byte to be recovered in the event of a communication error. Rev. 3.0 Jan. 2012 Second and most common, the receiver does not acknowledge to deliberately end an operation. For example, during a read operation, the FM24V01 will continue to place data onto the bus as long as the receiver sends acknowledges (and clocks). When a read operation is complete and no more data is needed, the receiver must not acknowledge the last byte. If the receiver acknowledges the last byte, this will cause the FM24V01 to attempt to drive the bus on the next clock while the master is sending a new command such as stop. Slave Address The first byte that the FM24V01 expects after a start condition is the slave address. As shown in Figure 4, the slave address contains the device type or slave ID, the device select address bits, a page address bit, and a bit that specifies if the transaction is a read or a write. Bits 7-4 are the device type (slave ID) and should be set to 1010b for the FM24V01. These bits allow other function types to reside on the 2-wire bus within an identical address range. Bits 3-1 are the device select address bits. They must match the corresponding value on the external address pins to select the device. Up to eight FM24V01 devices can reside on the same two-wire bus by assigning a different address to each. Bit 0 is the read/write bit. R/W=1 indicates a read operation and R/W=0 indicates a write operation. High Speed Mode (HS-mode) The FM24V01 supports a 3.4MHz high speed mode. A master code (0000 1XXXb) must be issued to place the device into high speed mode. Communication between master and slave will then be enabled for speeds up to 3.4MHz. A stop condition will exit HSmode. Single- and multiple-byte reads and writes are supported. See Figures 10 and 11 for HS-mode timings. Page 4 of 14 FM24V01 - 128Kb I2C FRAM Memory Operation Device Select Slave ID 1 0 1 0 A2 A1 A0 R/W 7 6 5 4 3 2 1 0 Figure 4. Slave Address Addressing Overview After the FM24V01 (as receiver) acknowledges the slave address, the master can place the memory address on the bus for a write operation. The address requires two bytes. The complete 14-bit address is latched internally. Each access causes the latched address value to be incremented automatically. The current address is the value that is held in the latch -either a newly written value or the address following the last access. The current address will be held for as long as power remains or until a new value is written. Reads always use the current address. A random read address can be loaded by beginning a write operation as explained below. After transmission of each data byte, just prior to the acknowledge, the FM24V01 increments the internal address latch. This allows the next sequential byte to be accessed with no additional addressing. After the last address (3FFFh) is reached, the address latch will roll over to 0000h. There is no limit to the number of bytes that can be accessed with a single read or write operation. Data Transfer After the address information has been transmitted, data transfer between the bus master and the FM24V01 can begin. For a read operation the FM24V01 will place 8 data bits on the bus then wait for an acknowledge from the master. If the acknowledge occurs, the FM24V01 will transfer the next sequential byte. If the acknowledge is not sent, the FM24V01 will end the read operation. For a write operation, the FM24V01 will accept 8 data bits from the master then send an acknowledge. All data transfer occurs MSB (most significant bit) first. The FM24V01 is designed to operate in a manner very similar to other 2-wire interface memory products. The major differences result from the higher performance write capability of F-RAM technology. These improvements result in some differences between the FM24V01 and a similar configuration EEPROM during writes. The complete operation for both writes and reads is explained below. Write Operation All writes begin with a slave address, then a memory address. The bus master indicates a write operation by setting the LSB of the slave address (R/W bit) to a ‘0’. After addressing, the bus master sends each byte of data to the memory and the memory generates an acknowledge condition. Any number of sequential bytes may be written. If the end of the address range is reached internally, the address counter will wrap from 3FFFh to 0000h. Unlike other nonvolatile memory technologies, there is no effective write delay with F-RAM. Since the read and write access times of the underlying memory are the same, the user experiences no delay through the bus. The entire memory cycle occurs in less time than a single bus clock. Therefore, any operation including read or write can occur immediately following a write. Acknowledge polling, a technique used with EEPROMs to determine if a write is complete is unnecessary and will always return a ready condition. Internally, an actual memory write occurs after the 8th data bit is transferred. It will be complete before the acknowledge is sent. Therefore, if the user desires to abort a write without altering the memory contents, this should be done using start or stop condition prior to the 8th data bit. The FM24V01 uses no page buffering. The memory array can be write-protected using the WP pin. Setting the WP pin to a high condition (VDD) will write-protect all addresses. The FM24V01 will not acknowledge data bytes that are written to protected addresses. In addition, the address counter will not increment if writes are attempted to these addresses. Setting WP to a low state (V SS) will deactivate this feature. WP is pulled down internally. Figures 5 and 6 below illustrate a single-byte and multiple-byte write cycles. Rev. 3.0 Jan. 2012 Page 5 of 14 FM24V01 - 128Kb I2C FRAM Start By Master S Stop Address & Data Slave Address 0 A Address MSB By FM24V01 A Address LSB A Data Byte A P Acknowledge Figure 5. Single Byte Write Start S By FM24V01 Stop Address & Data By Master Slave Address 0 A Address MSB A Address LSB A Data Byte A Data Byte A P Acknowledge Figure 6. Multiple Byte Write Read Operation There are two basic types of read operations. They are current address read and selective address read. In a current address read, the FM24V01 uses the internal address latch to supply the address. In a selective read, the user performs a procedure to set the address to a specific value. Current Address & Sequential Read As mentioned above the FM24V01 uses an internal latch to supply the address for a read operation. A current address read uses the existing value in the address latch as a starting place for the read operation. The system reads from the address immediately following that of the last operation. To perform a current address read, the bus master supplies a slave address with the LSB set to a ‘1’. This indicates that a read operation is requested. After receiving the complete slave address, the FM24V01 will begin shifting out data from the current address on the next clock. The current address is the value held in the internal address latch. Beginning with the current address, the bus master can read any number of bytes. Thus, a sequential read is simply a current address read with multiple byte transfers. After each byte the internal address counter will be incremented. Each time the bus master acknowledges a byte, this indicates that the FM24V01 should read out the next sequential byte. Rev. 3.0 Jan. 2012 There are four ways to properly terminate a read operation. Failing to properly terminate the read will most likely create a bus contention as the FM24V01 attempts to read out additional data onto the bus. The four valid methods are: 1. 2. 3. 4. The bus master issues a no-acknowledge in the 9th clock cycle and a stop in the 10th clock cycle. This is illustrated in the diagrams below. This is preferred. The bus master issues a no-acknowledge in the 9th clock cycle and a start in the 10th. The bus master issues a stop in the 9th clock cycle. The bus master issues a start in the 9th clock cycle. If the internal address reaches 3FFFh, it will wrap around to 0000h on the next read cycle. Figures 7 and 8 below show the proper operation for current address reads. Selective (Random) Read There is a simple technique that allows a user to select a random address location as the starting point for a read operation. This involves using the first three bytes of a write operation to set the internal address followed by subsequent read operations. To perform a selective read, the bus master sends out the slave address with the LSB set to 0. This specifies a write operation. According to the write protocol, the bus master then sends the address bytes that are loaded into the internal address latch. After the FM24V01 acknowledges the address, the bus master issues a start condition. This simultaneously aborts Page 6 of 14 FM24V01 - 128Kb I2C FRAM the write operation and allows the read command to be issued with the slave address LSB set to a ‘1’. The Start By Master operation is now a current address read. No Acknowledge Address Stop S Slave Address By FM24V01 1 A Data Byte Acknowledge 1 P Data Figure 7. Current Address Read Start By Master Address No Acknowledge Acknowledge Stop S Slave Address By FM24V01 1 A Data Byte A Acknowledge Data Byte 1 P Data Figure 8. Sequential Read Start Address By Master Start No Acknowledge Address Stop S Slave Address 0 A Address MSB A Address LSB By FM24V01 A S Slave Address 1 A Data Byte 1 P Data Acknowledge Figure 9. Selective (Random) Read Start Start & Enter HS-mode Address HS-mode command By Master S 0 0 0 0 1 X X By FM24V01 1 X S No Acknowledge Stop & Exit HS-mode Slave Address 1 A No Acknowledge Data Byte 1 P Data Acknowledge Figure 10. HS-mode Current Address Read Start S By FM24V01 Start & Enter HS-mode HS-mode command By Master 0 0 0 0 1 X X X 1 S Slave Address 0 A Stop & Exit HS-mode Address & Data Address MSB No Acknowledge A Address LSB A Data Byte A P Acknowledge Figure 11. HS-mode Byte Write Rev. 3.0 Jan. 2012 Page 7 of 14 FM24V01 - 128Kb I2C FRAM 5. 6. 7. Sleep Mode A low power mode called Sleep Mode is implemented on the FM24V01 device. The device will enter this low power state when the Sleep command 86h is clocked-in. Sleep Mode entry can be entered as follows: 1. 2. 3. 4. The master sends Reserved Slave ID 0x86 The FM24V01 sends an ACK. The master sends STOP to ensure the device enters sleep mode. Once in sleep mode, the device draws IZZ current, but the device continues to monitor the I2C pins. Once the master sends a Slave Address that the FM24V01 identifies, it will “wakeup” and be ready for normal operation within tREC (400 s max.). As an alternative method of determining when the device is ready, the master can send read or write commands and look for an ACK. While the device is waking up, it will NACK the master until it is ready. The master sends a START command. The master sends Reserved Slave ID 0xF8 The master sends the I2C-bus slave address of the slave device it needs to identify. The last bit is a ‘Don’t care’ value (R/W bit). Only one device must acknowledge this byte (the one that has the I2C-bus slave address). The master sends a Re-START command. Start Address By Master S By FM24V01 Rsvd Slave ID (F8) A Address Start Slave Address X A S Rsvd Slave ID (86) Stop A P Acknowledge Figure 12. Sleep Mode Entry Rev. 3.0 Jan. 2012 Page 8 of 14 FM24V01 - 128Kb I2C FRAM 5. 6. Device ID The FM24V01 device incorporates a means of identifying the device by providing three bytes of data, which are manufacturer, product ID, and die revision. The Device ID is read-only. It can be accessed as follows: 1. 2. 3. 4. The master sends Reserved Slave ID 0xF9 The Device ID Read can be done, starting with the 12 manufacturer bits, followed by the 9 part identification bits, and then the 3 die revision bits. The master ends the Device ID read sequence by NACKing the last byte, thus resetting the slave device state machine and allowing the master to send the STOP command. 7. The master sends a START command. The master sends Reserved Slave ID 0xF8 The master sends the I2C-bus slave address of the slave device it needs to identify. The last bit is a ‘Don’t care’ value (R/W bit). Only one device must acknowledge this byte (the one that has the I2C-bus slave address). The master sends a Re-START command. Note: The reading of the Device ID can be stopped anytime by sending a NACK command. Start Address By Master No Acknowledge Acknowledge Address Start Stop S Rsvd Slave ID (F8) A Slave Address By FM24V01 A S Rsvd Slave ID (F9) A Data Byte A Data Byte A Data Byte 1 Data Acknowledge Figure 13. Read Device ID Manufacturer ID 11 10 9 8 7 6 5 4 Product ID 3 2 1 0 8 Ramtron 0 0 0 0 0 0 0 7 6 5 4 Density 0 0 1 0 0 0 0 0 3 Die Rev. 2 1 0 2 1 0 0 0 0 0 Variation 1 N 0 0 0 Figure 14. Manufacturer and Product ID Density: 01h=128Kb, 02h=256Kb, 03h=512Kb, 04=1Mb Variation: Product ID bit 4 = S/N, Product ID bit 0 = reserved The 3-byte hex code for an FM24V01 will be: Rev. 3.0 Jan. 2012 0x00 0x41 0x00 Page 9 of 14 P FM24V01 - 128Kb I2C FRAM 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 (AEC-Q100-002 Rev. E) - Charged Device Model (AEC-Q100-011 Rev. B) - Machine Model (AEC-Q100-003 Rev. E) Package Moisture Sensitivity Level Ratings -1.0V to +4.5V -1.0V to +4.5V and VIN < VDD+1.0V * -55C to +125C 260 C 3.5kV 1.25kV 200V MSL-1 * Exception: The “VIN < VDD+1.0V” restriction does not apply to the SCL and SDA inputs. 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 = -40 C to + 85 C, VDD =2.0V to 3.6V unless otherwise specified) Symbol Parameter Min Typ Max Units VDD Main Power Supply 2.0 3.3 3.6 V IDD VDD Supply Current @ SCL = 100 kHz 90 175 A @ SCL = 1 MHz 200 400 A @ SCL = 3.4 MHz 500 1000 A ISB Standby Current 80 150 A IZZ Sleep Mode Current 4 8 A ILI Input Leakage Current ±1 A ILO Output Leakage Current ±1 A VIL Input Low Voltage -0.3 0.3 VDD V VIH Input High Voltage 0.7 VDD VDD + 0.3 V VOL1 Output Low Voltage (IOL = 2 mA, VDD ≥ 2.7V) 0.4 V VOL2 Output Low Voltage (IOL = 150 A) 0.2 V RIN Address Input Resistance (WP, A2-A0) For VIN = VIL (max) 50 K For VIN = VIH (min) 1 M Notes 1 2 2 3 3 4 Notes 1. SCL toggling between VDD-0.2V and VSS, other inputs VSS or VDD-0.2V. 2. SCL = SDA = VDD. All inputs VSS or VDD. Stop command issued. 3. VIN or VOUT = VSS to VDD. Does not apply to WP, A2-A0 pins. 4. The input pull-down circuit is stronger (50K) when the input voltage is below VIL and weak (1M) when the input voltage is above VIH. Rev. 3.0 Jan. 2012 Page 10 of 14 FM24V01 - 128Kb I2C FRAM AC Parameters (TA = -40 C to + 85 C, VDD =2.0V to 3.6V unless otherwise specified) F/S-mode HS-mode (CL