AVR526: Migrating from ATtiny24/44/84 to ATtiny24A/44A/84A 8-bit Microcontrollers 1 Introduction Application Note In order to optimize the manufacturing process and to further reduce current consumption, an optimized version of ATtiny24/44/84 has been introduced. The ATtiny24A/44A/84A is a functionally identical, drop-in replacement for the ATtiny24/44/84. All devices are subject to the same qualification process and same set of production tests, but as the manufacturing process is not the same some electrical characteristics differ. ATtiny24/44/84 and ATtiny24A/44A/84A have separate datasheets. This application note outlines the differences between the two devices and the datasheets. There is also a detailed change log to assist the user at the end of the ATtiny24A/44A/84A datasheet. Remember to always use the latest revision of the device datasheet. Minor differences in typical characteristics are not discussed in this document as long as the low and high limits remain the same. For detailed information about the typical characteristics, see sections “Electrical Characteristics” and “Typical Characteristics” of the device datasheets. Note: This application note serves as a guide to ease migration. For complete device details, always refer to the most recent version of the ATtiny24A/44A/84A data sheet. Rev. 8187B-AVR-03/11 2 Changes in Characteristics This section outlines such differences in characteristics that may have an effect on the application in which the device is used. For detailed information, refer to the most recent version of the device data sheets. 2.1 Current Consumption Active and Idle mode current consumption of the device have been reduced. The table below present typical current consumption figures at room temperature. All values are taken from device datasheets. Table 2-1. Typical Current Consumption of Device at Room Temperature Mode Active Idle Condition ATtiny24/44/84 ATtiny24A/44A/84A Change VCC = 2V, f = 1 MHz 0.33 mA 0.25 mA - 24% VCC = 3V, f = 4 MHz 1.6 mA 1.2 mA - 25% VCC = 5V, f = 8 MHz 5.0 mA 4.4 mA - 12% VCC = 2V, f = 1 MHz 0.11 mA 0.04 mA - 64% VCC = 3V, f = 4 MHz 0.40 mA 0.25 mA - 38% VCC = 5V, f = 8 MHz 1.5 mA 1.3 mA - 13% 2.2 Reset The table below summarizes the differences between the reset circuitry of ATtiny24/44/84 and that of ATtiny24A/44A/84A. Note, that early revisions of ATtiny24/44/84 were equipped with a Standard Power-On Reset, while later revisions included an Enhanced Power-On Reset circuit. Table 2-2. Power-On Reset ATtiny24A/44A/84A ATtiny24/44/84 (1) with Standard POR ATtiny24/44/84 with Enhanced POR Min Typ Max Min Typ Max VPOR 0.7 1.0 1.4 1.1 1.4 1.6 V VPOA 0.05 0.9 1.3 0.6 1.3 1.6 V SRON 0.01 - 4.5 0.01 - - V/ms Symbol Notes: (1) Unit 1. See ATtiny24/44/84 datasheet for revision information. 3 Datasheet Changes For a summary of changes, see the revision history at the end of the ATtiny24A/44A/84A data sheet. 2 AVR526 8187B-AVR-03/11 Disclaimer Headquarters International Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131 USA Tel: (+1)(408) 441-0311 Fax: (+1)(408) 487-2600 www.atmel.com Atmel Asia Limited Unit 1-5 & 16, 19/F BEA Tower, Millennium City 5 418 Kwun Tong Road Kwun Tong, Kowloon HONG KONG Tel: (+852) 2245-6100 Fax: (+852) 2722-1369 Atmel Munich GmbH Business Campus Parkring 4 D-85748 Garching b. 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