LM49155_15 Datasheet, PDF (1/10 Pages) Texas Instruments – Uplink Noise Suppression & Downlink SNR Enhancement Analog Audio Subsystem

LM49155
www.ti.com
SNAS492 – JULY 2010
PRODUCT BRIEF
LM49155
Uplink Noise Suppression & Downlink
SNR Enhancement Analog Audio Subsystem
Check for Samples: LM49155
FEATURES
1
•2 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
• E²S Class D Amplifier with ALC
• Ground Referenced Headphone Outputs with
Advanced Click Pop Suppression
• Micro-power shutdown
APPLICATIONS
• Mobile Phones
• Portable Electronic Devices
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 I²C 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 E²S 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
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Table 1. Key Specifications
Uplink Far Field Noise Suppression
Electrical FFNS_E at f = 1kHz
Downlink SNR Enhancement Earpiece Amplifier
Class D Loudspeaker Amplifier R_L = 15μH+8Ω+15μH
P_OUT, THD+N ≤ %, V_DD = 5.0V
Headphone Amplifier R_L = 32Ω
P_OUT, THD+N ≤ %, HPV_DD = 1.8V
Near-Field SNR Enhancement
Downlink SNRI_E
VALUE
34
6 to 18
16
1.35
19
UNIT
dB (typ)
dB (typ)
W (typ)
mW (typ)
1
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2010, Texas Instruments Incorporated