BD3481FS-E2 - Stereo Sound Processor IC | ROHM Semiconductor
MPN: BD3481FS-E2 ✓ ActiveBD3481FS-E2 Overview
A sound processor is an integrated circuit that conditions and routes audio signals within a compact audio system. Its functional hierarchy is analog audio IC, sound processor, audio channel, and integrated circuit. By combining channel selection, amplification, level control, and equalization, this type of device reduces the number of discrete analog blocks required in compact consumer-audio equipment while allowing the product design to remain primarily analog.
The BD3481FS integrates a stereo four-channel input selector, a gain amplifier, a stereo primary volume stage, a four-channel fader stage, and a two-band equalizer. These blocks support source selection and level adjustment within one package. The manufacturer documentation also describes the device as suitable for designs where microcomputer control is unnecessary, reducing control-software complexity compared with a software-commanded audio processor.
The BD3481 family shares a documented architecture with BD3482FS. Both are described as sound processors containing a stereo four-channel input selector, gain amplifier, stereo primary volume control, four-channel fader volume, and two-band equalizer. The BD3481FS-E2 is supplied in a 20-pin, 0.8 mm-pitch SSOP, making compact analog-audio board layouts possible where component height and lead pitch are important constraints.
Typical uses include compact stereo systems, radio equipment, cassette-style audio products, televisions, portable audio equipment, and other consumer products requiring analog source selection and volume control. The integrated architecture is particularly useful when several input sources must be selected and adjusted without relying on a system controller for routine signal-path operations.
The principal design task is preserving clean signal routing through a dense analog network. Decoupling, grounding, input-source isolation, and control-settling behavior should be evaluated on the assembled board because switching transients and ground-current paths can affect audio performance. The exact pin assignments, recommended component values, supply-current limits, and detailed electrical limits must be taken from the manufacturer datasheet before schematic release.
This product page organizes the documented BD3481FS-E2 functionality, packaging information, application guidance, and engineering trade-offs. It also distinguishes the BD3482FS family relationship from a verified drop-in replacement, helping designers avoid assuming that a similar sound processor can be substituted without footprint and functional verification.
Drop-in alternatives for BD3481FS-E2 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
No drop-in alternatives available for this product.
Request AlternativesBD3481FS-E2 Maximum Ratings & Electrical Characteristics
| Product Type | Stereo sound processor IC |
| Supply Voltage | 8.5 V |
| Input Channel Configuration | 4 channels |
| Audio Channel Configuration | Stereo |
| Input Selector | Stereo 4-channel input selector |
| Gain Amplifier | Integrated |
| Primary Volume Control | Stereo |
| Fader Volume Control | 4 channels |
| Equalizer | 2-band |
| Microcomputer Control Required | No |
| Package | 20-pin SSOP |
| Lead Pitch | 0.8 mm |
| Mounting Type | Surface mount |
BD3481FS-E2 20-pin ssop Pin Configuration Guide
Pin configuration for BD3481FS-E2 (20-pin ssop package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for BD3481FS-E2.
Refer to the datasheet for full pin configuration.
Typical Applications
BD3481FS-E2 is suitable for 6 applications: Compact Stereo Radio, Television Audio Signal Path, Portable Audio Equipment, Cassette-Style Audio Product, Multi-Source Audio Selector, Two-Band Audio Equalizer.
Compact Stereo Radio
The BD3481FS-E2 fits a compact analog radio signal path requiring selection among several stereo sources, adjustable gain, primary level control, fader control, and tone shaping. Its 20-pin SSOP with 0.8 mm pitch helps conserve board area, while the 8.5 V supply requirement aligns with suitably designed analog audio rails. Integrating these blocks can reduce the number of separate analog stages around the radio’s audio output section. The design should still reserve suitable filtering, decoupling, and grounding around the IC, especially if multiple sources are switched during operation.
Recommended
Television Audio Signal Path
A television or display product can use the BD3481FS-E2 to consolidate several analog audio inputs into a controlled stereo output path. The integrated four-channel input selector supports source arbitration, the gain amplifier establishes the working signal level, and the primary stereo volume and four-channel fader stages provide adjustable output control. The two-band equalizer adds basic tone shaping without requiring separate passive networks for each source. Its compact surface-mount package is useful where PCB area is limited, although analog-to-digital wall separation and grounding require careful implementation.
Recommended
Portable Audio Equipment
BD3481FS-E2 is applicable to portable or compact audio products that require analog source selection and volume management close to the speaker amplifier. The 20-pin, 0.8 mm-pitch SSOP reduces the footprint compared with several separate selector and amplifier blocks, while the integrated gain and equalization functions shorten the analog signal path. The 8.5 V supply capability must be coordinated with the product’s power architecture rather than assumed to regulate directly from a battery. Follow the manufacturer’s voltage and current limits and place decoupling close to the device pins.
Recommended
Cassette-Style Audio Product
The BD3481FS-E2 supports legacy cassette-style products that combine multiple stereo sources with mechanical transport control and conventional analog volume adjustments. Its integrated selector, gain amplifier, primary volume stage, fader control, and two-band equalizer reproduce several functions normally distributed across a preamplifier. The dedicated 8.5 V supply requirement fits a properly designed analog rail, and the 20-pin SSOP supports compact surface-mount construction. Mechanical switches and motor-control circuitry should remain electrically isolated from the sensitive audio path to prevent transient contamination.
Recommended
Multi-Source Audio Selector
A multi-source audio selector can use the BD3481FS-E2 when the design needs four stereo input choices followed by common gain, volume, fader, and equalization stages. Centralizing these functions gives each selected source a consistent downstream path and reduces duplicated analog circuitry. The integrated architecture is particularly useful in equipment with fixed mechanical or analog controls because it does not require a particular microcomputer for routine switching. Care must be taken to maintain the required signal level at the selector inputs and to prevent unused-source crosstalk from degrading the selected channel.
Recommended
Two-Band Audio Equalizer
The BD3481FS-E2 can serve as a compact two-band audio equalizer and level-conditioning stage in compact stereo equipment. Input selection and gain adjustment occur before the fader and equalizer sections, allowing several sources to share one common output chain. This arrangement reduces duplicated equalizer circuitry and provides a unified control structure. When implementing the circuit, observe the manufacturer’s recommended input amplitude, bypass values, and signal-routing diagram. Layout should keep high-gain stages away from switching nodes and digital timing circuitry to minimize noise injection.
Recommended
Recommended Products Summary
Engineering reference data for BD3481FS-E2 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product |
|---|---|
| Brand | ROHM Semiconductor |
| Package | 20-pin SSOP |
| Lead Pitch | 0.8 mm |
| Supply Voltage | 8.5 V |
| Product Type | Stereo sound processor |
| Input Selector | Stereo 4-channel input selector |
| Primary Volume | Stereo |
| Fader Volume | 4 channels |
| Equalizer | 2-band |
| Microcomputer Control | Not required |
Design Notes
Place the manufacturer-recommended supply bypass capacitors immediately beside the BD3481FS-E2 supply and ground pins. Because one package contains input selection, gain, volume, fader, and equalization functions, shared supply impedance can couple noise or switching transients across otherwise separate channels. Route the analog signal path away from digital clocks, motor-control lines, and power-converter switching nodes, then keep the ground return path short and continuous beneath the relevant circuitry.
Preserve the documented signal-level range at each stage and follow the manufacturer application circuit for input and output coupling values. The source selector, gain amplifier, and volume stages can amplify residual noise and crosstalk if an inactive source is not isolated correctly. Use separate input paths where necessary, maintain consistent impedance between stereo channels, and test channel-to-channel switching transients with the final cables, switches, and source impedances connected.
Do not treat the BD3482FS family relationship as proof that a different ordering code is pin-to-pin compatible with BD3481FS-E2. Confirm the package drawing, numbered pin table, supply limits, control levels, gain range, and external component values before releasing a substitute design. Also avoid adding a required microcomputer-control assumption: the manufacturer describes the BD3481FS as operating without a particular microcomputer, but the physical control network still requires correct implementation.
Keep the equalizer and fader sections away from high-current return paths because changing source or volume level can create temporary imbalance in the ground reference. Shorten feedback and filter connections, avoid routing audio nets beneath digital buses, and maintain symmetric left and right layouts where channel matching matters. Validate the finished board with channel-sweep, switching-transient, and idle-noise measurements because a sound processor integrates several stages whose interaction is not apparent from the block diagram alone.
Compliance Information
The available product documentation identifies the part, electrical architecture, package, and ordering suffix but does not state the requested environmental and material-compliance statuses. AEC-Q100 qualification is not applicable because BD3481FS-E2 is not identified as an automotive-qualified device.
