AN207b FM24V01 Replaces Two FM24CL64s Author: Harsha Medu Associated Project: No Associated Part Family: FM24V01, FM24CL64 Software Version: None Related Application Notes: None AN207b discusses the key differences which need to be considered when migrating from FM24CL64 to FM24V01. Description 2 The FM24V01, a 128-Kbit I C F-RAM, is a potential replacement for two FM24CL64 (64-Kbit) devices; FM24CL64 is now obsolete. For most designs, the FM24V01 device can be considered a superset of the FM24CL64. The two devices are identical in terms of pinout, package dimensions, and read/write functionality. This application note discusses the key differences between the two devices apart from density, which need to be considered when migrating from FM24CL64 to FM24V01. From a hardware point of view, the key differences between the two devices are the added features of FM24V01, like operation down to 2.0 V and Device ID. In terms of speed, both operate up to 1 MHz but the FM24V01 extends the speed to 3.4 MHz. A memory write sequence for the FM24V01 device is shown in Figure 1. Note the addition of address bit A13 in the serial address stream. This is the MSB bit for the 128-Kbit devices. A compatibility chart for the two devices is given in Table 1. A detailed comparison is shown in Table 2. Table 1. Compatibility Chart FM24CL64 Feature or Spec Upward Compatible From a software point of view, the two devices are compatible. Aside from the additional address bit to access twice the memory, the two devices are read / write compatible. Both devices use the same two-byte address. Remember that the 128-Kbit device address wraps at 0x3FFF while the 64-Kbit wraps at 0x1FFF. For systems that use a single FM24CL64 device, the transition to the FM24V01 could be as straightforward as changing your firmware to hold the address bit A13 LOW during SRAM read/writes. For systems that use two FM24CL64s, firmware needs to be modified to use the address bit A13 to access the full 128-Kbit memory. Is FM24V01 compatible? Package Yes Pinout Yes Temperature Range Yes Operating Voltage Yes Operating Current Yes Standby Current No Read / Write Function Yes Timing / Frequency Yes Data Retention Endurance Refer to Table 2 Yes Figure 1. FM24V01 Write Sequence X X 13 12 11 10 9 8 www.cypress.com 7 6 5 4 Document No. 001-86815 Rev. *A 3 2 1 0 1 FM24V01 Replaces Two FM24CL64s Table 2. Detailed Comparison Package Types Package Outlines Pinout Temperature Range Operating Voltage Range Active Supply Current Standby Current Output LOW Voltage (VOL) Read / Write Function Clock Frequency Data Retention FM24CL64 FM24V01 Comments -G, -DG -G Same, “green” SOIC package. FM24V01 is not offered in DFN package. SOIC-8, DFN-8 SOIC-8 Same SOIC outline and board footprint. FM24V01 is not offered in DFN package. - - Same –40 ºC to +85 ºC –40 ºC to +85 ºC Same 2.7 V to 3.65 V 2.0 V to 3.6 V 75 µA @ 100 kHz 175 µA @ 100 kHz 400 µA @ 1 MHz 400 µA @ 1 MHz 1 µA 150 µA (max) 80 µA (typical) 0.4 V @ IOL = 3 mA 0.4 V @ IOL = 2 mA - - 1 MHz 3.4 MHz 45 years (+85 ºC) FM24V01 offers a wider operating range FM24V01 offers the same active current at 1 MHz FM24V01 has higher standby current FM24CL64 has specification better output LOW Same 2-byte addressing, same Slave IDs, same device select bits, A13 must be low FM24V01 offers higher speed 10 years (+85 ºC) 38 years (+75 ºC) Unlimited 1E+14 FM24V01’s endurance is large enough to be considered as unlimited for all practical applications. For a 64-byte loop, at 1 MHz, FM24V01’s endurance is 1700 years. VDD Power-Up Ramp Rate (tVR) - 50 µs / V Power-up ramp rate should be slower than 50 µs / V for FM24V01 VDD Power-Down Ramp Rate (tVF) - 100 µs / V Power-down ramp rate should be slower than 100 µs / V for FM24V01 Power-Up to First Access (tPU) - 0.25 ms After power-up, the first access of FM24V01 should be after 0.25 ms Endurance Critical Considerations All the parameter differences in Table 2 should be considered during the migration to FM24V01. The critical differences are discussed in this section. System designers are also recommended to review the detailed datasheets when migrating to the new part. Read / Write Function The FM24V01 device has an extra address bit, A13, to support the additional 64-Kbit memory when compared to the FM24CL64. Setting A13 to a 0 level will address the 64-Kbits of your current FM24CL64 application. Setting A13 to a 1 level will address the additional 64-Kbits of the FM24V01. Note that roll over will not happen at 0x1FFF in FM24V01; instead it will roll over at 0x3FFF. VDD Ramp Rate VDD power-up and power-down ramp rate specifications are added in FM24V01 device. Ensure that the power-up ramp rate is slower than 50 µs / V and power-down ramp rate is slower than 100 µs / V in your system. www.cypress.com Document No. 001-86815 Rev. *A 2 FM24V01 Replaces Two FM24CL64s Power-Up to First Access Power-up to first access specification is added in FM24V01 device. Ensure that the FM24V01 device is accessed only after 0.25 ms from power-up. Conclusion AN207b discusses the differences between FM24CL64 and FM24V01 which need to be considered during migration. www.cypress.com Document No. 001-86815 Rev. *A 3 FM24V01 Replaces Two FM24CL64s Document History Document Title: FM24V01 Replaces Two FM24CL64s - AN207b Document Number: 001-86815 Revision ECN Orig. of Change Submission Date Description of Change ** 3944550 GVCH 03/26/2013 New Spec. *A 4281483 MEDU 03/07/2014 Updated to Cypress Template. Updated package outline for FM24CL64. Updated operating voltage range for FM24CL64 from “2.7 V to 3.6 V” to “2.7 V to 3.65 V”. Updated Active Supply Current for FM24CL64 from "70 µA @ 100 kHz" to "75 µA @ 100 kHz". Added data retention spec to FM24V01 at 85 ºC. Removed VIH(max) spec from Table 2. www.cypress.com Document No. 001-86815 Rev. *A 4 FM24V01 Replaces Two FM24CL64s Worldwide Sales and Design Support Cypress maintains a worldwide network of offices, solution centers, manufacturer’s representatives, and distributors. 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Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cypress reserves the right to make changes without further notice to the materials described herein. Cypress does not assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. Use may be limited by and subject to the applicable Cypress software license agreement. www.cypress.com Document No. 001-86815 Rev. *A 5