Features
| • | AC'97 Rev2 compliant |
| • | National's 3D Sound circuitry |
| • | High quality Sample Rate Conversion (SRC) from 4kHz to 48kHz in 1Hz increments. |
| • | Multiple Codec Support |
| • | True Line Level Output with volume control in addition to standard Line Out |
| • | Advanced power management support |
| • | Digital 3V and 5V compliant |
Description The LM4548 is an audio codec for PC systems which is fully PC98 compliant and performs the analog intensive functions of the AC97 Rev2 architecture. Using 18-bit Sigma-Delta A/D's and D/A's, the LM4548 provides 90dB of Dynamic Range.
The LM4548 was designed specifically to provide a high quality audio path and provide all analog functionality in a PC audio system. It features full duplex stereo A/D's and D/A's and an analog mixer with 4 stereo and 3 mono inputs, each of which has separate gain, attenuation and mute control. The LM4548 also provides the additional True Line-Level output and National's 3D Sound stereo enhancement.
The LM4548 supports variable sample rate conversion as defined in the AC97 Rev2 specification. The sample rate for the A/D and D/A can be programmed separately to convert any rate between 4kHz - 48kHz with a resolution of 1Hz. The AC97 architecture separates the analog and digital functions of the PC audio system allowing both for system design flexibility and increased performance.
Key Specification
| • Analog Mixer Dynamic Range | 97dB (typ) |
| • D/A Dynamic Range | 89dB (typ) |
| • A/D Dynamic Range | 90dB (typ) |
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Applications
| • | Desktop PC Audio Systems |
| • | Portable PC Systems |
| • | Mobile PC Systems |
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