ATtiny261/461/861系列过去的型号都停产了，目前都是新型号ATtiny261A/461A/861A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 ATtiny261/461/861 has been introduced.

The ATtiny261A/461A/861A is a functionally identical, drop-in replacement for the ATtiny261/461/861. 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.

ATtiny261/461/861 and ATtiny261A/461A/861A 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 ATtiny261A/461A/861A 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 ATtiny261A/461A/861A data sheet.

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.

2.2 Reset
The table below summarizes the differences between the reset circuitry of ATtiny261/461/861 and that of ATtiny261A/461A/861A.

3 New or Updated Bits and Registers
The following table illustrates bits that have changed since ATtiny261/461/861. Some bits were marked as reserved in ATtiny261/461/861 and some bits have another use in ATtiny261A/461A/861A.

4 Datasheet Changes
For a summary of changes, see the revision history at the end of the ATtiny261A/461A/861A data sheet.