Product category: Analogue and Mixed Signal ICs
News Release from: National Semiconductor | Subject: LM4935
Edited by the Electronicstalk Editorial Team on 11 January 2006
Novel package hosts smallest audio
subsystem
The industry's smallest audio subsystem with a mono Class D speaker driver integrates all the analogue and digital audio functions needed for smart phones and VoIP terminals.
The industry's smallest audio subsystem with a mono Class D speaker driver from National Semiconductor integrates all the analogue and digital audio functions needed for smart phones and voice-over-Internet protocol (VoIP) phones A member of the Boomer audio power amplifier family, the LM4935 subsystem provides high-quality output power with a minimal number of external components
This article was originally published on Electronicstalk on 5 Jan 2001 at 8.00am (UK)
Related stories
Dual-port Gigabit Ethernet transceiver
National Semiconductor has announced the DP83862, a low-cost, highly integrated dual-port 10/100/1000 physical layer transceiver.
World's smallest multifunction supervisory ICs
National Semiconductor has announced a family of supervisory ICs with a variety of factory-programmable features that can be configured in hundreds of possible combinations.
"Smart phones bring the convergence of PDA functionality, wireless connectivity and, increasingly, consumer audio to one full-featured device", said Roland Dorn, Product Marketing Manager Audio at National Semiconductor in Europe.
"The LM4935 allows handset designers to add the new audio features consumers demand".
"Its integration drives design simplicity and takes up a minimum amount of board space".
Further reading
Leadless leadframe package shrinks LDO
National Semiconductor has introduced a full-featured 500mA LDO regulator for medium-current applications in computing devices and portable products.
Boomer shrinks stereo headphone amplification
New from National Semiconductor, the LM4811 Boomer audio amplifier is a 105mW stereo headphone amplifier for use in 3 and 5V systems requiring a headphone output and volume control.
Frugal dual-channel A/D conversion
National Semiconductor has introduced a dual-channel 8bit A/D convertor with record low-power dissipation levels.
The LM4935 is a complete audio subsystem with multiple digital and analogue inputs and outputs.
Operating on supplies ranging from 1.8 to 5.5V, the LM4935 combines several features: a Class D speaker amplifier delivering 570mW into an 8ohm load; a stereo headphone amplifier that supports output capacitor-less (OCL) or AC-coupled operation delivering 30mW per channel into 32ohm; a mono earpiece amplifier delivering 30mW into a 32ohm load; and a line output for an external-powered handsfree speaker providing filterless Class D stereo speaker capability.
Other features include a successive approximation register (SAR) analogue-to-digital convertor (ADC) for system monitoring and a high-fidelity digital-to-analogue convertor.
The LM4935's bidirectional I2S digital interface with pulse-code modulation (PCM) capability transmits any audio file or voice data transmission back and forth from the baseband application-specific integrated circuit (ASIC) or processor to the analogue outputs.
The subsystem also features a read/write I2C compatible digital interface.
In addition, the LM4935 gives engineers design flexibility in arranging analogue inputs through a sophisticated switching/mixing circuitry, eliminating the need for external audio switches and mixing components.
Two analogue inputs allow the LM4935 to accept a stereo signal from an FM radio or operate as two separate mono inputs that can accept other analogue input signals.
Additional analogue inputs allow for differential mono input and output from a GSM, CDMA or other cellphone radio module as well as a baseband application-specific integrated circuit (ASIC).
Two additional inputs support internal and external microphone capability.
National's new micro SMDxt package provides high input/output analogue devices with the smallest possible footprint for any given pin count.
The micro SMDxt, which builds on the success of National's micro SMD package, utilises a unique solder ball structure that enables high-reliability products with bump counts up to 100 bumps at a 0.5mm pitch.
With the new package, reliability requirements for typical portable applications such as thermal cycling, thermal shock, drop test and flex test can be met without the use of an underfill.
Available now in a 49-bump micro SMDxt package, the LM4935 is priced at $3.95 each in 1000-unit quantities.
• National Semiconductor: contact details and other news
• Email this article to a colleague
• Register for the free Electronicstalk email newsletter
• Electronicstalk Home Page
Search the Pro-Talk network of sites
