Class-D amplifier suppresses EMI
Silicon Laboratories has introduced the industry’s first 5-Watt stereo class-D amplifier that mitigates electromagnetic interference (EMI). The Si270x amplifier is ideal for use in a wide range of price- and noise-sensitive consumer audio products including smart phone docking stations, tabletop radios, TV sound bars and monitors, boom boxes and battery-powered radios. Two issues have impeded the adoption of Class D amplifiers. The first is the high EMI emissions inherent to traditional class-D solutions, which interfere with AM/FM radio and smart phone operation. The second issue is the high cost of adding expensive filtering and shielding for EMI regulatory compliance.
The Si270x class-D amp can co-exist with AM and FM radios.
The Si270x amplifier uses multi-layer EMI mitigation technology to suppress traditional class-D interference at its source, enabling easier EMI compliance, AM/FM radio co-existence and smart phone compatibility in consumer audio products. Compared to existing class D amplifiers, the Si270x reduces radiated interference by 10X in the EMI compliance band, by 100X in the FM radio band and by 1000X across the AM band.
This reference design is available for the Si270x class-D audio amplifier.
The Si270x Class D amplifier can enable a 2.5X increase in play time over Class A/B-based systems while using only half the number of batteries. A consumer audio system based on the Si270x amplifier can provide up to 8.4 hours of play time using four AA alkaline batteries.
The Si270x Class D amplifier is designed to be combined the Si473x AM/FM radio tuner. The latest Si473x devices offer a stereo analog input and internal analog-to-digital converters (ADCs) multiplexed with the radio tuner front-end to support auxiliary analog system inputs without the need for additional external ADCs. The combination provides consumer audio products such as tabletop radios, docking stations, boom boxes, and mini-stereo systems.
A GUI lets you quickly registers and change parameters on the development system.
Samples and pre-production quantities of the Si270x Class D audio amplifiers are available today in a 24-pin QFN package. Pricing in 10,000-unit quantities for the Si270x amplifiers begins at $1.17 (USD). To help accelerate application development, Silicon Labs offers audio engineers a full-featured Si270x-A-EVB evaluation board priced at $325 (USD).
This eval sytem lets you examine the Si270x hardware.
Karla commented:
Nice vid. !I'm thinking of bynuig a mandolin.What kind of songs can you play on a mandolin?I like those Irish jiggs and stuff, but can you also play more rocky songs on it?I play bass guitar voor a year and a half now so I have a bit experience with instruments.
Thehobe commented:
Last time I tried to demonstrate a class D amplifier, I hooked it up to a simple transistor radio and no sound in the audio range was heard. The AM and FM bands of the radio were totaly masked by the interference from the class D amplifier. This is certainly a good development on the class D front!
