Interesting amplifier - LF

Fox, Terry tlfox at
Thu Mar 25 08:59:06 CST 2004

This STMicroelectronics STA5150 may work on LF?  200W, with open-loop
gain to 1.6MHZ...

STMicroelectronics Audio Power Amplifier Chip Delivers 200W Output,
Targets Multi-channel Applications 			


STMicroelectronics STA5150
<>  combines Indigo's
BASH high efficiency topology and Bipolar-CMOS-DMOS process technology
to deliver highest power on market 

Geneva, January 22, 2004 - STMicroelectronics (NYSE: STM) announced
today that the company is shipping a new single-chip audio power
amplifier that delivers 200W, the highest power available from an
integrated commercial device. Called STA5150
<> , the new amplifier
combines the patented BASH high-efficiency technology licensed from
Indigo Manufacturing with ST's proprietary Bipolar-CMOS-DMOS (BCD)
process technology.

Merging the benefits of class AB and class D, the BASH technology uses
DMOS power transistors operated in class AB mode, reducing the EMI and
distortion typical of class D switching amplifiers. To maximize
efficiency, by continually adjusting the power supply voltage, depending
on the amplitude of the amplified audio signal, a constant voltage drop
is achieved across the output transistors, completely independent of the
output amplitude. Implementing this technique allows the STA5150
<>  to deliver 200W
into a four-ohm load with less than 10% distortion, and with an
efficiency three times better than a conventional Class AB.

"By bringing together Indigo's patented high efficiency amplification
technique and ST's best-in-class BCD technology we have once again set
the standard for performance in integrated audio amplifiers," said
Riccardo Ferrari, General Manager of ST's Audio Division. "This new
amplifier chip reconfirms ST's technological leadership, since 1969, in
audio power amplification chips." 

Each STA5150 <>
device includes a 200W audio power amplifier channel. This amplifier is
mainly used in multi-channel multimedia audio systems such as the 5.1
channel surround sound commonly used in A/V receivers. Other
BASH-equipped audio power amplifiers available include the 2x100 STA575,
2x70W STA550 and STA530, a quad amplifier fully configurable from 4x50W
to 2x50W+ 1x100W. The power amplifiers are used in conjunction with a
digital processor, the STABP01, which is the controller for a buck
(step-down) converter and implements the BASH supply voltage variation
technique, by using a reference feedback signal derived from the power
amplifier stage. 

"We are very pleased that Indigo's high efficiency technology has been
adopted by STMicroelectronics for the new STA5150
<>  and other
integrated power amplifiers," said Joe Riggi, Vice President of Indigo
Manufacturing Inc. "This fruitful co-operation between our companies
benefits system designers by delivering high power multi-channel audio
at a competitive cost. 

STA5150 <>  power
amplifiers are assembled in ST's proprietary Flexiwatt plastic package,
developed to provide excellent thermal performance, easy assembly and
robustness. The products include comprehensive protection features that
guard against overload and anomalous supply conditions. By using a BASH
specific external circuit topology, it's possible to provide an intended
reduction of the power supply voltage, sensing the power stage and the
external buck converter to achieve a further improvement of the overall
systems' protection scheme. 

About STMicroelectronics
STMicroelectronics is a global leader in developing and delivering
semiconductor solutions across the spectrum of microelectronics
applications. An unrivalled combination of silicon and system expertise,
manufacturing strength, Intellectual Property (IP) portfolio and
strategic partners positions the Company at the forefront of
System-on-Chip (SoC) technology and its products play a key role in
enabling today's convergence markets. The Company's shares are traded on
the New York Stock Exchange, on Euronext Paris and on the Milan Stock
Exchange. In 2002, the Company's net revenues were $6.32 billion and net
earnings were $429.4 million. Further information on ST can be found at 

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