Audio and video

It is easy to take for granted the technological wonders that enable everyday home entertainment. Looking under the skin of these products reveals continual revolutions in technology. These developments empower entertainment products to perform new functions, comply with ever-evolving standards, or keep in line with the price cuts expected on existing technologies.

So whether its drivers and equalisers for HDMI that support the latest digital HDTV systems, or high-quality, low-cost amplifier circuits that power the ubiquitous MP3 player, there is a wealth of innovation with which designers can gain a competitive advantage.

Some examples in this issue of FTM include: the ALC5620 multichannel codec from Realtek which helps to power the surround sound and high-quality PC audio market (page 080329); the Rohm BU9437 which is effectively a single-chip MP3 system (page 080334); and a range of Class-D amplifier products from leading manufacturers, such as NXP Semiconductors (pages 080319 and 080323) and International Rectifier (page 080321).

FTM also covers commonly overlooked developments that are key to making these systems work. Tyco Electronics’ connectors, for example, can save valuable space by offering both HDMI and external SATA connectors in a single unit (page 080333).

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Tiny amplifier ICs for ultra-slimline audio solutions

NXP Semiconductors has introduced four amplifier ICs in packages under 1mm high for portable, batterypowered and PC-peripheral applications.

A choice of power ratings, mono or stereo outputs, and power-saving features are provided, and all devices include thermal shutdown and output shortcircuit protection.

The SA58670 and SA58671 are stereo Class-D amplifiers optimised for filterless design to save board space and component count in miniaturised systems. For energyefficient operation in battery-powered applications, both devices operate from 2.2V to 5.5V and feature fast start-up time of 3.5ms. The SA58670 is capable of driving up to 2.1W per channel into a 4Ω load at 5V operating voltage, and consumes less than 1µA in shutdown mode. The SA58671 will drive up to 1.3W per channel into 4Ω at 5V. Both ICs require only two external components and provide two pins for gain selection, with preset values of 6, 12, 8 and 24dB. For systems operating from supply voltages between 2V and 9V, the SA58631 3W Class-AB, single-channel amplifier and SA58632 2.2W stereo amplifier feature thermally-enhanced packages to maximise power density and reliability. Both devices feature a Bridge-Tied Load (BTL) output with complementary PNPNPN output transistors. An external Mode pin, compatible with CMOS input signals, is also provided for control of integrated mute and low-power standby modes. The gain is adjusted from 6dB to 30dB using two external resistors.

 

APPLICATIONS SA58631 and SA58632 Professional and amateur mobile radio Sounder cards Proximity detectors SA58670 and SA5671 USB speakers Personal TV receivers Educational toys

 

 

NXP Semiconductors/SA58632