AN318 Migrating from FM25L16 to FM25L16B Author: Girija Chougala Associated Project: No Associated Part Family: FM25L16, FM25L16B Software Version: None Related Documents: For a complete list, click here AN318 discusses the key differences that need to be considered when migrating from FM25L16 to FM25L16B. FM25L16 is now obsolete and this application note explains how FM25L16B is a replacement for FM25L16. Table 1. Compatibility Chart Introduction FM25L16B, a 16-Kbit SPI F-RAM™, is a replacement device for FM25L16, which is now obsolete. The two devices are identical in terms of pinouts and read/write functionality. In terms of speed, FM25L16 operates up to 18 MHz and FM25L16B operates up to 20 MHz. This application note discusses the key differences between the two devices that need to be considered when migrating from FM25L16 to FM25L16B. FM25L16 Feature or Spec Yes (SOIC) Package Drop-In Replacement or Not? From a software point of view, the two devices are identical. The two devices are read/write compatible. Both devices use the same two-byte address. From a hardware point of view the key differences are the higher standby current of the FM25L16B and the TDFN package dimensions. Table 1 shows the compatibility chart of FM25L16 and FM25L16B. For a detailed comparison, see Table 3. Is FM25L16B compatible? No (TDFN) Pinout Yes Temperature Range Yes Operating Voltage Yes Operating Current Yes Standby Current No Read / Write Function Yes Timing / Frequency Yes Data Retention Yes Endurance Yes Ordering Part Numbers Table 2 gives the recommended FM25L16B ordering part numbers that correspond to the now obsolete FM25L16 ordering part numbers. Table 2. Recommended Ordering Part Numbers for Migration FM25L16 Ordering Part Number FM25L16 -G FM25L04B Status Obsolete Ordering Part Number FM25L16B -G FM25L16-GTR FM25L16B -GTR FM25L16-DG FM25L16B -DG FM25L16-DGTR FM25L16B -DGTR www.cypress.com Comments Status In production Document No. 001-86841 Rev. *B No hardware or software change is required No software change. Hardware change is required. 1 Migrating from FM25L16 to FM25L16B Comparison of FM25L16 and FM25L16B 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 FM25L16 FM25L16B -G, -DG -G, -DG Comments Identical “green” SOIC package but different “Green” TDFN package SOIC-8, SOIC-8, TDFN-8 (3 mm x 6.4 mm) TDFN-8 (4 mm x 4.5 mm) - - Identical –40 ºC to +85 ºC –40 ºC to +85 ºC Identical 2.7 V to 3.6 V 2.7 V to 3.6 V Identical 300 µA @ 1 MHz 200 µA @ 1 MHz 5.5 mA @ 18 MHz 3.0 mA @ 20 MHz 1 µA 6 µA (max) 3 µA (typical) - - 18 MHz 20 MHz Identical outlines and board footprints for SOIC but different for TDFN FM25L16B offers lower active current FM25L16B has higher standby current Identical 2-byte addressing, Identical op-codes Improved speed in FM25L16B 10 years (+85 ºC) Data Retention 45 years (+85 ºC) 38 years (+75 ºC) Data retention is lower 151 years (+65 ºC) FM25L16B is virtually unlimited at 20 MHz (85 years for a 64-byte loop) Endurance (Write/Read Cycles) Unlimited 1E+14 VDD Power-Up Ramp Rate (tVR) 50 µs / V 30 µs / V Improved power-up ramp rate in FM25L16B VDD Power-Down Ramp Rate (tVF) 100 µs / V 30 µs / V Improved power-down ramp rate in FM25L16B 1 ms 1 ms Power-Up to First Access (tPU) Identical Critical Considerations You should consider all the parameter differences mentioned in Table 3 during the migration to FM25L16B. This section discusses the critical differences. System designers should also review the datasheet when migrating to the new part. Package Outline Both FM25L16 and FM25L16B devices are offered in SOIC and TDFN packages. While the SOIC package dimensions are the same, there is a difference in TDFN package dimensions. The package dimensions of FM25L16 are 3 mm x 6.4 mm and that of FM25L16B are 4 mm x 4.5 mm. Summary AN318 discussed the differences between FM25L16 and FM25L16B that need to be considered during migration to the FM25L16B. www.cypress.com Document No. 001-86841 Rev. *B 2 Migrating from FM25L16 to FM25L16B Related Documents Datasheet FM25L16B: 16-Kbit (2 K × 8) Serial (SPI) F-RAM datasheet Application Note AN304 – SPI GUIDE FOR F-RAM www.cypress.com Document No. 001-86841 Rev. *B 3 Migrating from FM25L16 to FM25L16B Document History Document Title: Migrating from FM25L16 to FM25L16B - AN318 Document Number: 001-86841 Revision ECN Orig. of Change Submission Date Description of Change ** 3944550 GVCH 03/26/2013 New Spec. *A 4279018 MEDU 02/12/2014 Updated to Cypress Template. Updated max operating range from 3.65 V to 3.6 V. Updated clock frequency for FM25L16 from 20 MHz to 18 MHz. Updated “VDD Power-Down Ramp Rate” for FM25L16B from 100 µs / V to 30 µs / V. Updated “Power-Up to First Access” for FM25L16B from 10 ms to 1 ms. Added “Power-Up to First Access”, “VDD Power-Up Ramp Rate” , “VDD Power-Down Ramp Rate” for FM25L16. *B 4498653 GVCH 09/22/2014 Changed title from “Differences between FM25L16 and FM25L16B” to “Migrating from FM25L16 to FM25L16B.” Updated abstract. Added “Ordering Part Numbers” section. Added title for Table 3. Added “Related Documents” section. www.cypress.com Document No. 001-86841 Rev. *B 4 Migrating from FM25L16 to FM25L16B 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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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. 001-86841 Rev. *B 5