AN315 Migrating from FM25C160 to FM25C160B Author: Girija Chougala Associated Project: No Associated Part Family: FM25C160, FM25C160B Software Version: None Related Documents: For a complete list, click here AN315 discusses the key differences that need to be considered when migrating from FM25C160 to FM25C160B. FM25C160 is now obsolete and this application note explains how FM25C160B is a replacement for FM25C160. Table 1. Compatibility Chart Introduction FM25C160B, a 16-Kbit SPI F-RAM™, is a replacement device for FM25C160, which is now obsolete. The two devices are identical in terms of pinouts and read/write functionality. In terms of speed, both operate up to 20 MHz and have the same timing specifications. This application note discusses the key differences between the two devices that need to be considered when migrating from FM25C160 to FM25C160B. FM25C160 Feature or Spec Drop-In Replacement or Not? For most designs, FM25C160B is a drop-in replacement for FM25C160. From a software point of view, the two devices are identical. From a hardware point of view the key difference is the lower active current in FM25C160B. Additionally, FM25C160B 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 FM25C160B compatible? Package Yes Pinout Yes Temperature Range Yes Operating Voltage Yes Operating Current Yes Standby Current Yes Read / Write Function Yes Timing / Frequency Yes Data Retention Refer to Table 3 Endurance Yes Table 1 shows the compatibility chart of FM25C160 and FM25C160B. For a detailed comparison, see Table 3. Ordering Part Numbers Table 2 gives the recommended FM25C160B ordering part numbers that correspond to the now obsolete FM25C160 ordering part numbers. Table 2. Recommended Ordering Part Numbers for Migration FM25C160 Ordering Part Number FM25C160-G FM25C160-GTR www.cypress.com FM25C160B Status Obsolete Ordering Part Number FM25C160B-G Comments Status In production FM25C160B-GTR Document No. 001-86837 Rev. *B No hardware or software change is required 1 Migrating from FM25C160 to FM25C160B Comparison of FM25C160 and FM25C160B 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 FM25C160 FM25C160B -G -G SOIC-8 SOIC-8 - - Identical –40 ºC to +85 ºC –40 ºC to +85 ºC Identical 4.5 V to 5.5 V 4.5 V to 5.5 V Identical 400 µA @ 1 MHz 250 µA @ 1 MHz 8.0 mA @ 20 MHz 4.0 mA @ 20 MHz 10 µA 10 µA - - 20 MHz 20 MHz Comments Identical “green” SOIC package Identical outline and board footprint FM25C160B offers lower active current Identical Identical 2-byte addressing, Identical opcodes 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) 1E+12 1E+14 FM25C160B has better endurance VDD Power-Up Ramp Rate (tVR) - 30 µs / V Power-up ramp rate should be slower than 30 µs / V for FM25C160B VDD Power-Down Ramp Rate (tVF) - 30 µs / V Power-down ramp rate should be slower than 30 µs / V for FM25C160B Power-Up to First Access (tPU) - 1 ms After power-up, the first access FM25C160B should be after 1 ms of Critical Considerations You should consider all the parameter differences mentioned in Table 3 during the migration to FM25C160B. 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 FM25C160B device. Ensure that the power-up and power-down ramp rates are slower than 30 µs / V in your system. Power-Up to First Access Power-up to first access specification is added in FM25C160B device. Ensure that the FM25C160B device is accessed only after 1 ms from power-up. Summary AN315 discussed the differences between FM25C160 and FM25C160B that need to be considered during migration to the FM25C160B. www.cypress.com Document No. 001-86837 Rev. *B 2 Migrating from FM25C160 to FM25C160B Related Documents Datasheet FM25C160B: 16-Kbit (2 K × 8) Serial (SPI) F-RAM datasheet Application Note AN304 – SPI GUIDE FOR F-RAM www.cypress.com Document No. 001-86837 Rev. *B 3 Migrating from FM25C160 to FM25C160B Document History Document Title: Migrating from FM25C160 to FM25C160B - AN315 Document Number: 001-86837 Revision ECN Orig. of Change Submission Date Description of Change ** 3944550 GVCH 03/26/2013 New Spec. *A 4278908 MEDU 03/05/2014 Updated to Cypress Template. Updated Endurance for FM25C160B from E+12 to E+14. Updated “VDD Power-Down Ramp Rate” for FM25C160B from 100 µs / V to 30 µs / V. Updated “Power-Up to First Access” for FM25C160B from 10 ms to 1 ms. *B 4498652 GVCH 09/19/2014 Changed title from “Differences between FM25C160 and FM25C160B” to “Migrating from FM25C160 to FM25160B.” Updated abstract. Added “Ordering Part Numbers” section. Added title for Table 3. Added “Related Documents” section. www.cypress.com Document No. 001-86837 Rev. *B 4 Migrating from FM25C160 to FM25C160B 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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