SLAU472C February 2013 – November 2023 TAS2505 , TAS2505-Q1
The TAS2505 has an integrated class-D mono speaker driver (SPKP/SPKM) capable of driving an 8-Ω or 4-Ω differential load. The speaker driver can be powered directly from the battery supply (2.7 V to 5.5 V) on the SPKVDD pins; however, the voltage (including spike voltage) must be limited below the absolute-maximum voltage of 6 V.
The speaker driver is capable of supplying 800 mW per channel with a 3.6-V power supply. Through the use of digital mixing, the device can connect one or both digital audio playback data channels to either speaker driver; this also allows digital channel swapping if needed.
The class-D speaker driver can be powered on by writing to page 1, register 45, bit D1. The class-D output-driver gain can be controlled by writing to page 1, register 48, bits D6–D4, and it can be muted by writing to page 1, register 48, bit D6 - D4 = 000.
The TAS2505 has a short-circuit protection feature for the speaker drivers that is always enabled to provide protection. If the output is shorted, the output stage shuts down on the overcurrent condition. (Current limiting is not an available option for the higher-current speaker driver output stage.) In case of a short circuit, the output is disabled and a the enable bit is reset to 0 on page 1, register 45, bit D1.
If shutdown occurs due to an overcurrent condition, then the device requires to re-enable the output stage. The speaker power-stage reset is done by setting page 1, register 45, bit D1 to 1. If the fault condition has been removed, then the device returns to normal operation. If the fault is still present, then another shutdown occurs. Repeated resetting (more than three times) is not recommended, as this could lead to overheating.
To minimize battery current leakage, the SPKVDD voltage level should not be less than the AVDD voltage level.
The TAS2505 has a thermal protection (OTP) feature for the speaker driver which is always enabled to provide protection. If the device is overheated, then the output stops switching. When the device cools down, the output resumes switching. An overtemperature status flag is provided as a read-only bit on page 0, register 45, bit D7. The OTP feature is for self-protection of the device. If die temperature can be controlled at the system/board level, then overtemperature does not occur.