Single-stage Class D amp delivers 300 watts

Dallas&#8212Texas Instruments says its TAS5261 is the industry's highest power single-chip Class D amplifier stage, delivering more than 300 watts into a 4-ohm speaker (or 220 watts into 6 ohms, 125 watts into 8 ohms) for AV and DVD receivers and home theater systems. That's double the capability of any other Class D power stage, according to the company. Also announced, its TAS5162 stereo product can deliver 200 watts per channel at 6 ohms and 125 watts at 8 ohms.

“TI's Class-D expertise allows OEMs to take advantage of all the benefits of a digital amplifier, including a cost-effective, all-digital, end-to-end implementation and crystal-clear audio with no signal degradation at even the highest power levels,” said Art George, senior vice president of the company's high-performance analog business unit. “The TAS5261 is unmatched in how much power and current it can reliably drive, more than doubling what is available in today's digital amplifier power stages.”

A viable alternative to traditional high-power systems, which generally utilize Class AB amplifiers or rather large Class D modules, the PWM-driven TAS5261 and TAS5162, part of the company's PurePath Digital portfolio of compact solutions, offers an efficiency of greater than 95 percent (reportedly several percent higher than any competing device) and a signal-to-noise ratio (SNR) of 110 dB. The TAS5261 features a total harmonic distortion plus noise (THD+N) of less than 0.09 percent at 125 watts and 8 ohms (THD+N would be 10 percent at 315 watts and 4 ohms).

In addition to its high-current handling capability (up to 17 amps), the TAS5261/TAS5162 includes two-stage current-limiting circuitry to deal with speaker resonance conditions and impedance drop versus frequency, and cycle-by-cycle short-circuit monitoring to prevent speaker damage, says Kevin Belnap, marketing manager for Home Entertainment Audio and High Performance Analog. The TI design also does away with the need to deal with power-up sequencing and related pre-biasing issues, a standout feature at this power level, he says.

Beyond this edge in performance, designers are going to be happy with the economic advantages, says Belnap. Indeed, the new Class D chips integrate the required MOSFET H-bridges to reduce board size, ease layout, simplify heat sink design and cut manufacturing costs. The materials and real-estate savings become especially dramatic for the larger systems, he says: An 8-channel design using these new parts require essentially four chips, versus four drivers and 32 MOSFETs in the traditional design for the same power output.

The TAS5162 is also pin-compatible with earlier TAS51x2 devices, enabling OEMs to design a single board that can deliver 100 watts (TAS5142), 125 watts (TAS5152), or 200 watts (TAS5162) per channel, thereby eliminating multiple designs and simplifying logistics.

Click here for the TAS5261's datasheet. Click here for preliminary info on the TAS5162.
The TAS5261 is available today in volume in PSOP-3 packaging at $5.25 each in quantities of 1,000 or more. The TAS5162, available in both PSOP-3 and HTSSOP packaging, is slated for volume production by December.

Texas Instruments , 1-800-477-8924,

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