Document
www.DataSheet4U.com
LM4673 Filterless, 2.65W, Mono, Class D Audio Power Amplifier
December 2005
LM4673 Filterless, 2.65W, Mono, Class D Audio Power Amplifier
General Description
The LM4673 is a single supply, high efficiency, 2.65W, mono, Class D audio amplifier. A low noise, filterless PWM architecture eliminates the output filter, reducing external component count, board area consumption, system cost, and simplifying design. The LM4673 is designed to meet the demands of mobile phones and other portable communication devices. Operating on a single 5V supply, it is capable of driving a 4Ω speaker load at a continuous average output of 2.1W with less than 1% THD+N. Its flexible power supply requirements allow operation from 2.4V to 5.5V. The LM4673 has high efficiency with speaker loads compared to a typical Class AB amplifier. With a 3.6V supply driving an 8Ω speaker, the IC’s efficiency for a 100mW power level is 80%, reaching 88% at 400mW output power. The LM4673 features a low-power consumption shutdown mode. Shutdown may be enabled by driving the Shutdown pin to a logic low (GND). The gain of the LM4673 is externally configurable which allows independent gain control from multiple sources by summing the signals. Output short circuit and thermal overload protection prevent the device from damage during fault conditions.
Key Specifications
j Efficiency at 3.6V, 400mW into 8Ω speaker 88% (typ) j Efficiency at 3.6V, 100mW into 8Ω speaker 80% (typ) j Efficiency at 5V, 1W into 8Ω speaker j Quiescent current, 3.6V supply j Total shutdown power supply current j Single supply range j PSRR, f = 217Hz
86% (typ) 2.1mA (typ) 0.01µA (typ) 2.4V to 5.5V 78dB
Features
n n n n n n n n Mono Class D Operation No output filter required for inductive loads Externally configurable gain Very fast turn on time: 17µs (typ) Minimum external components "Click and pop" suppression circuitry Micro-power shutdown mode Available in space-saving 0.4mm pitch micro SMD and LLPTm (Future Product) packages
Applications
n Mobile phones n PDAs n Portable electronic devices
Typical Application
201522J3
FIGURE 1. Typical Audio Amplifier Application Circuit
Boomer ® is a registered trademark of National Semiconductor Corporation.
© 2005 National Semiconductor Corporation
DS201522
www.national.com
LM4673
Connection Diagrams
9 Bump micro SMD Package micro SMD Marking
20152257
Top View X — Date Code T — Die Traceability G — Boomer Family G4 — LM4673TM
20152236
Top View Order Number LM4673TM See NS Package Number TMD09GGA Leadless Leadframe Package (LLP) LLP Marking
20152202 20152201
Top View Order Number LM4673SD See NS Package Number SDA08A Contact NSC Sales Office for Availability (Future Product)
Top View Z — Plant Code XY — Date Code TT — Die Traceability L4673 — LM4673SD (Future Product)
www.national.com
2
LM4673
Absolute Maximum Ratings (Notes 1, 2)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Offi.