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- LM1894
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- Last added
- 2012-04-05
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National Semiconductor LM1894 Datasheet
The LM1894 is a stereo dynamic noise reduction (DNR) circuit designed for audio playback systems. It operates with a wide supply range, low‑cost external components, and provides up to 10 dB of CCIR/ARM‑weighted noise reduction without requiring encoded source material.
The document includes absolute maximum ratings, detailed electrical characteristics, typical performance curves, external component recommendations, circuit operation explanations, and application hints such as placement before tone and volume controls and methods to adjust bandwidth and attack/decay times.
National Semiconductor LM1894 specifications
| Operating Supply Range | 4.5 V to 18 V |
|---|---|
| Supply Current (typical) | 30 mA |
| Effective Noise Reduction (CCIR/ARM weighted) | ≈10 dB |
| Input Overload | 1 Vrms |
| Voltage Gain (typical) | -1 V/V |
Source: National Semiconductor LM1894 Dynamic Noise Reduction System Datasheet
All National Semiconductor LM1894 documents by type
Ratings, dimensions and ordering codes, for selection and design work.
Questions answered in these manuals
What supply voltage range is recommended for the LM1894?
The device operates with a supply voltage from 4.5 V up to 18 V.
How can the bandwidth of the LM1894 be adjusted?
Bandwidth can be changed by altering the values of capacitors C3 and C12 or by adjusting the size of C10, which sets attack and decay times.
What is the effective noise reduction provided by the LM1894?
The LM1894 can achieve about 10 dB of CCIR/ARM weighted noise reduction, with a maximum of roughly 14 dB in certain conditions.
From: National Semiconductor LM1894 Dynamic Noise Reduction System Datasheet
What supply voltage range should be used with the LM1894?
The device operates over a wide supply range of 4.5 V to 18 V.
From: National Semiconductor LM1894 Dynamic Noise Reduction System Datasheet