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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
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Analog Mixer Dynamic Range
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97dB (typ)
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D/A Dynamic Range
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89dB (typ)
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A/D Dynamic Range
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90dB (typ)
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Applications
Desktop PC Audio Systems
Portable PC Systems
Mobile PC Systems
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