This article refers to the address: http://
National Semiconductor has announced two single-chip Boomer® audio power amplifiers in an ultra-small package. The two models, the LM4962 and LM4953, are the two latest models of National Semiconductor's advanced ceramic speaker driver series, which have the advantage of driving higher capacitive loads, making them ideal for mobile phones, smart phones, laptops, etc. Portable electronics.Ceramic speakers are very different from traditional moving coil speakers. Ceramic speakers are capacitive loads, not resistive loads, which require higher voltages and lower currents. Traditional moving coil speakers are 4mm thick or larger, while ceramic speakers are only 0.7mm thick and weigh no more than one gram. For more information on these two types of speakers, refer to the National Semiconductor's audio.national.com/CHS website on the "Audio Education Series eBooks" page.
National's LM4962 ceramic speaker driver is only 5mm x 5mm, which is much smaller than the company's older (25mm x 25mm), which saves 80% on board space. Since the capacitive load of ceramic speakers requires a high driving voltage, the LM4962 chip is specially equipped with a boost converter to meet the requirements of high voltage output. In addition, the chip has an audio power amplifier that supports mono ceramic speakers. Since the boost converter built into the LM4962 chip can also drive another external high-voltage audio amplifier, such as National's LM4951, this driver can also drive stereo speakers.
The LM4953 ceramic speaker driver is National's first audio amplifier that can drive ceramic speakers with a charge pump. It has the advantage of adding only 8 external components, which saves board space and eliminates the need for expensive Regulators and larger inductors.
The LM4962 ceramic speaker driver requires only a single 3.2V DC power supply to provide 15V peak-to-peak voltage for the bridge load (BTL) without total harmonic distortion and noise (THD+N) of more than 1%. In addition, the LM4962 chip features overcurrent protection and overvoltage protection to protect the boost converter. The built-in DC/DC converter features a soft-start function. The LM4962 chip features a low-power mode dedicated to headphones and a high-power mode that can drive ringing and hands-free speakers to help save more battery power.
The LM4953 is available in a 3mm x 4mm package, but with an audio amplifier and charge pump built in, it can boost the 3.6V supply voltage and provide a peak-to-peak voltage of up to 12.6V for a 2uF + 30W bridge load. Wave distortion and noise will not exceed 1%.
Both speaker drivers feature a low-power shutdown mode and internal thermal shutdown protection without the need for a startup capacitor or transient voltage suppression circuit. In addition, both chips feature advanced "switch/switch" noise suppression circuitry that completely eliminates the noise generated during on/off. The unit gains of these two chips are very stable and can be configured with an external gain setting resistor.
The LM4962 is available in a 28-bump, thin micro SMD package and is priced at $2.50 each. The LM4953 is available in a 14-pin pull-back LLP® package and is priced at $1.85 each. The LM4951 is available in LLP and micro SMD packages.
Nantong Boxin Electronic Technology Co., Ltd. , https://www.bosencontrols.com