Features
| • | 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 microSMD package |
Description The LM4671 is a single supply, high efficiency 2.5W switching 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 LM4671 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 LM4671 has high efficiency with speaker loads compared to a typical Class AB amplifier. With a 3V supply driving an 8Ω
speaker, the IC's efficiency for a 100mW power level is 80%, reaching 88% at 400mW output power.
The LM4671 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 LM4671 is externally configurable which allows independent gain control from multiple sources by summing the
signals.
Key Specification
| ■
Efficiency @ 3.6V, 100mW into
8Ω speaker
|
80% (typ)
|
| ■
Efficiency @ 3.6V, 400mW into
8Ω speaker
|
88% (typ)
|
| ■
Efficiency @ 5V, 1W into 8Ω
speaker
|
86% (typ)
|
| ■
Quiescent current, 3.6V supply
|
2.8mA (typ)
|
| ■
Total shutdown power supply
current
|
0.01µA (typ)
|
| ■
Single supply range
|
2.4V to 5.5V
|
Applications
| • | Mobile phones |
| • | PDAs |
| • | Portable electronic devices |
|
|
LM4671
