Features Noise cancellation for uplink and downlink without DSP-type artifacts, distortions or delays Adapting AGC on ambient noise level & downlink signal strength for earpiece Downlink adjustable noise-reducing high pass filter E 2S Class D Amplifier with ALC Ground Referenced Headphone Outputs with Advanced Click Pop Suppression Micro-power shutdown Description The LM49155 is a fully integrated audio subsystem designed for portable handheld applications such as cellular phones. The LM49155 combines a Noise Suppression microphone amplifier, a 1.35W mono class D amplifier with ALC, class AB earpiece driver with AGC, a high efficiency, stereo, ground referenced headphone amplifier with click pop suppression and I 2C modes select and volume control. The LM49155 features analog fully differential input, and differential output microphone amplifier designed to reduce background acoustic noise, while delivering superb speech clarity in voice communication applications. Downlink SNR enhancement with an advanced acoustic AGC technology to adjust output levels. The LM49155 speaker amplifier features National’s unique output limiter that provides both a no-clip feature and speaker protection. The E 2S class D amplifier features a patented, ultra low EMI PWM architecture that significantly reduces RF emissions while preserving audio quality and efficiency. The headphone drivers feature National’s ground referenced architecture that creates a ground-referenced output from a single, low-voltage supply. The LM49155 is available in an ultra-small 36-bump micro SMD package (3.434mm x 3.459mm x 0.6mm). Notice: This document is not a full datasheet. For more information regarding this product or to order samples please contact your local National Semiconductor sales office or visit http://www.national.com/support/dir.html Key Specification ■  Uplink Far Field Noise Suppression  Electrical FFNSE at f = 1kHz 34dB (typ) ■  Downlink SNR Enhancement Earpiece Amplifier   Near-Field SNR Enhancement  Downlink SNRIE 6 to 18dB (typ) 16dB (typ) ■  Class D Loudspeaker Amplifier RL = 15μH+8Ω+15μH  POUT, THD+N ≤ %, VDD = 5.0V 1.35W (typ) ■  Headphone Amplifier RL = 32Ω  POUT, THD+N ≤ %, HPVDD = 1.8V 19mW (typ) Applications Mobile Phones Portable Electronic Devices

Typical Application click for larger image	Block Diagram click for larger image

Datasheets

Title		Size	Date	Other Language
	LM49155 Uplink Noise Suppression & Downlink SNR Enhancement Analog Audio Subsystem	185 Kbytes	21-Jul-10

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LM49155TL/NOPB RoHS Status	MICRO SMD	Full production Lead Time: 6 weeks	Distributor Region Qty DIGI-KEY Worldwide 485	$2.25 each at 1K+ pcs	reel of 250

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM49155.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM49155 is located at RoHS Status.

Part Number(s) (NSID)	Weight (milligrams)	Type	Pins	MSL Rating	Peak Reflow	RoHS Status	CAD Symbols	Models	Package Marking Format
LM49155TL/NOPB	N/A	MICRO SMD	36	1	260	Detail	N/A	N/A	XYTT I GN7

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM49155.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM49155 is located at RoHS Status.

CAD Symbols and Models N/A

Models N/A