AN212 Migrating from FM24CL64 to FM24CL64B Author: Girija Chougala Associated Project: No Associated Part Family: FM24CL64, FM24CL64B Software Version: None Related Documents: For a complete list, click here AN212 discusses the key differences that need to be considered when migrating from FM24CL64 to FM24CL64B. FM24CL64 is now obsolete and this application note explains how FM24CL64B is a replacement for FM24CL64. Table 1 shows the compatibility chart of FM24CL64 and FM24CL64B. For a detailed comparison, see Table 3. Introduction FM24CL64B, a 64-Kbit I2C F-RAM™, is a replacement device for FM24CL64, which is now obsolete. The two devices are identical in terms of pinout, package composition and dimensions, read/write functionality, Write Protect operation, and address pin functionality. This application note discusses the key differences between the two devices that need to be considered when migrating from FM24CL64 to FM24CL64B. Table 1. Compatibility Chart FM24CL64 Feature or Spec Drop-In Replacement or Not? For most designs, FM24CL64B is a drop-in replacement for FM24CL64. From a software point of view, the two devices are identical. From a hardware point of view, the key difference between the two devices is that the FM24CL64B has a slightly higher standby current. Additionally, FM24CL64B datasheet adds a power-up and power-down ramp rate specification of 30 µs / V and a power-up to first-access specification of 1 ms. Is FM24CL64B 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 Refer to Table 3 Endurance Yes Ordering Part Numbers Table 2 gives the recommended FM24CL64B ordering part numbers that correspond to the now obsolete FM24CL64 ordering part numbers Table 2. Recommended Ordering Part Numbers for Migration FM24CL64 Ordering Part Number FM24CL64-G FM24CL64B Status Obsolete Ordering Part Number FM24CL64B-G FM24CL64-GTR FM24CL64B-GTR FM24CL64-DG FM24CL64B-DG FM24CL64-DGTR FM24CL64B-DGTR www.cypress.com Comments Status In production Document No. 001-86818 Rev. *B No hardware or software change is required. 1 Migrating from FM24CL64 to FM24CL64B Comparison of FM24CL64 and FM24CL64B Table 3 gives a detailed comparison of the two devices. Table 3. Detailed Comparison Package Types Package Outlines Pinout Temperature Range Operating Voltage Range Active Supply Current Standby Current Read / Write Function Clock Frequency FM24CL64 FM24CL64B Comments -G, -DG -G, -DG Identical “green” SOIC and TDFN packages SOIC-8, TDFN-8 SOIC-8, TDFN-8 Identical footprint - - Identical –40 ºC to +85 ºC –40 ºC to +85 ºC Identical 2.7 V to 3.65 V 2.7 V to 3.65 V Identical 75 µA @ 100 kHz 100 µA @ 100 kHz 400 µA @ 1 MHz 300 µA @ 1 MHz 1 µA (max) 6 µA (max) 3 µA (typical) - - 1 MHz 1 MHz SOIC outline and board The FM24CL64B offers lower active current at 1 MHz FM24CL64B current has higher standby Identical 2-byte addressing, Identical Slave IDs, Identical Device Select bits Identical 10 years (+85 ºC) Data Retention 45 years (+85 ºC) 38 years (+75 ºC) Data retention is lower 151 years (+65 ºC) Endurance (Write/Read Cycles) Unlimited VDD Power-Up Ramp Rate (tVR) 1E+14 FM24CL64B is virtually unlimited at 1 MHz (1700 years for a 64-byte loop) 30 µs / V Power-up ramp rate should be greater than 30 µs / V for FM24CL64B VDD Power-Down Ramp Rate (tVF) - 30 µs / V Power-down ramp rate should be greater than 30 µs / V for FM24CL64B Power-Up to First Access (tPU) - 1 ms After power-up, the first access of FM24CL64B should be after 1 ms Critical Considerations You should consider all the parameter differences mentioned in Table 3 during the migration to FM24CL64B. This section discusses the critical differences. System designers should also review the datasheet when migrating to the new part. VDD Ramp Rate VDD power-up and power-down ramp rate specifications are added in FM24CL64B device. Ensure that the power-up and power-down ramp rates are greater than 30 µs / V in your system. Power-Up to First Access The power-up to first access specification is added in the FM24CL64B device. Ensure that the FM24CL64B device is accessed only after 1 ms from power-up. Summary AN212 discussed the differences between FM24CL64 and FM24CL64B that need to be considered during migration to the FM24CL64B. This application note demonstrates that FM24CL64B is a drop-in replacement for FM24CL64 for most designs. www.cypress.com Document No. 001-86818 Rev. *B 2 Migrating from FM24CL64 to FM24CL64B Related Documents Datasheet FM24CL64B: 64-Kbit (8 K × 8) Serial (I2C) F-RAM datasheet www.cypress.com Document No. 001-86818 Rev. *B 3 Migrating from FM24CL64 to FM24CL64B Document History Document Title: Migrating from FM24CL64 to FM24CL64B - AN212 Document Number: 001-86818 Revision ECN Orig. of Change Submission Date Description of Change ** 3944550 GVCH 03/26/2013 New Spec *A 4271353 MEDU 02/04/2014 Updated to Cypress Template Updated Active Supply Current for FM24CL64 from "70 µA @ 100 kHz " to "75 µA @ 100 kHz " Added data retention spec to FM24CL64B at 85 ºC Updated Power-up to first Access for FM24CL64B from "10 ms" to "1 ms" Removed VIH (max) spec from Table 2 *B 4498650 GVCH 09/10/2014 Changed title from “Differences between FM24CL64 and FM24CL64B” to “Migrating from FM24CL64 to FM24CL64B.” Updated abstract. Added “Ordering Part Numbers” section. Added title for Table 3. Added “Related Documents” section. www.cypress.com Document No. 001-86818 Rev. *B 4 Migrating from FM24CL64 to FM24CL64B Worldwide Sales and Design Support Cypress maintains a worldwide network of offices, solution centers, manufacturer’s representatives, and distributors. To find the office closest to you, visit us at Cypress Locations. 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