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
