Features
E
2S class D amplifier
Ground referenced headphone outputs — eliminates output coupling capacitors
I
2C volume and mode control
Mono earpiece amplifier
Flexible output for speaker and headphone output
20–bump micro SMD package
Soft enable function
“Click and Pop” suppression circuitry
Thermal shutdown protection
Low supply current
Micro-power shutdown
Description The LM49150 is a fully integrated audio subsystem designed for portable handheld applications such as cellular phones. Part
of National's Power Wise® product family, the LM49150 consumes very low power in the various modes of operation and still
providing great audio performance. The LM49150 combines a 1.25W mono E
2S (Enhanced Emission Suppression) class D amplifier, 135mW Class AB earpiece amplifier, 42mW/channel stereo ground reference
headphone amplifiers, volume control, and mixing circuitry into a single device.
The filterless class D amplifier delivers 1.25W into an 8Ω load with <1% THD+N with a 5V supply. The E
2S class D amplifier features a patented, ultra low EMI PWM architecture that significantly reduces RF emissions while preserving
audio quality. The 42mW/channel headphone drivers feature National’s ground referenced architecture that creates a ground-referenced
output from a single supply, eliminating the need for bulky and expensive DC-blocking capacitors, saving space and minimizing
cost.
The LM49150 features a fully differential mono input, and two single-ended stereo inputs. The three inputs can be mixed/multiplexed
to either the speaker or headphone amplifiers. Each input channel has an independent, 32-step digital volume control. The
headphone output stage features an additional, 8-step gain control, while the speaker output stage has a selectable 6dB or
12dB gain. The mixer, volume control and device mode select are controlled through an I
2C compatible serial interface.
The LM49150’s superior click and pop suppression eliminates audible transients on power-up/down and during shutdown. The
LM49150 is available in a ultra-small 20-bump micro SMD package (2.225mm X 2.644mm).
Key Specification
| ■
Output power at VDD = 5V:
|
|
| Speaker:
RL = 8Ω BTL, THD+N
≤ 1%
|
1.25W (typ)
|
| Headphone:
RL = 32Ω SE, THD+N
≤ 1%
|
42mW (typ)
|
| Earpiece:
RL = 8Ω SE, THD+N
≤ 1%
|
135mW (typ)
|
| ■
Output power at VDD = 3.3V:
|
|
| Speaker:
RL = 8Ω BTL, THD+N
≤ 1%
|
520mW (typ)
|
| Headphone:
RL = 32Ω BTL, THD+N
≤ 1%
|
42mW (typ)
|
| Earpiece:
RL = 8Ω SE, THD+N
≤ 1%
|
35mW (typ)
|
| ■
Output Offset
|
|
| LS Mode
|
9mV (typ)
|
| HP Mode
|
1mV (typ)
|
| Earpiece
|
1mV (typ)
|
| ■
Single Supply Operation (VDD)
|
2.7 to 5.5V
|
| ■
I
2C Single Supply Operation
|
1.7 to 5.5V
|
Applications
Mobile Phones
PDAs
Portable Electronics
|
Also Recommended
| LM49151▲ | Class D With ALC, Ground Reference Headphone |
|
|
LM49151
