ATtiny24/ATtiny44系列过去的型号都停产了，目前都是以新型号ATtiny24A/ATtiny44A系列来替代。以下是官方提供的相关区别说明：
1 Introduction
In order to optimize the manufacturing process and to further reduce current consumption, an optimized version of ATtiny24/44 has been introduced.

The ATtiny24A/44A is a functionally identical, drop-in replacement for the ATtiny24/44. 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 and ATtiny24A/44A 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 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 data sheet.

2 Changes in Characteristics
This section outlines such differences in characteristics that may have an effect onthe 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.

2.2 Reset
The table below summarizes the differences between the reset circuitry of ATtiny24/44 and that of ATtiny24A/44A. Note, that early revisions of ATtiny24/44 were equipped with a Standard Power-On Reset, while later revisions included an Enhanced Power-On Reset circuit.

3 Datasheet Changes
For a summary of changes, see the revision history at the end of the ATtiny24A/44A data sheet.