Si476x - Automotive AM/FM HD Radio Receiver IC | Skyworks
MPN: Si476 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.05 | $7.05 |
| 10 | $6.42 | $64.20 |
| 100 | $5.9 | $590.00 |
| 500 | $5.35 | $2,675.00 |
| 1,000 | $4.9 | $4,900.00 |
Si476 Overview
An integrated radio receiver IC combines the RF front end, mixed-signal processing, and audio processing of a traditional discrete radio tuner into a single chip. Within the signal-chain hierarchy, the Si476x sits at the tuner stage of the receiver subsystem, feeding demodulated audio and digital radio data to a host processor. The family belongs to the broader category of RF receiver ICs and automotive infotainment semiconductors.
Key features of the Si476x include worldwide FM band support (64-108 MHz), worldwide AM band support, and AM/FM HD Radio (HDR) support. Additional variants extend coverage to weather band, shortwave, and longwave frequencies, and dual-antenna FM phase diversity reception for improved multipath rejection in challenging automotive environments.
Technical depth: the Si476x incorporates an integrated digital processor for the European Radio Data System (RDS) and the North American Radio Broadcast Data System (RBDS), including all required symbol decoding, block synchronization, and error checking in hardware. This offloads the host MCU from real-time data broadcast decoding. The all-CMOS integration eliminates manual alignment, reducing manufacturing cost and improving long-term frequency stability compared with discrete tuner architectures.
Typical applications include automotive head units and infotainment systems, HD Radio broadcast reception, RDS/RBDS-enabled car radios, and weather-band receivers. The automotive-grade performance targets OEM infotainment platforms that demand high receiver quality under noisy vehicle electrical environments.
Design consideration: the device requires three supply rails - analog 5 V (VA), digital 3.3 V (VD), and separate interface supply rails (VIO1/VIO2) - so power-rail sequencing and decoupling must be planned early in the PCB design.
This page synthesizes distributor data, same-family drop-in variants, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for Si476 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
SI4762-A20-AM
✅ Drop-In📋 Reference alternative (not in catalog)
SI4763-A10-GM
✅ Drop-In📋 Reference alternative (not in catalog)
SI4764-A20-AM
✅ Drop-In📋 Reference alternative (not in catalog)
SI4762-A20-AMR
✅ Drop-In📋 Reference alternative (not in catalog)
Si476 Specifications
| Product Type | Automotive AM/FM Radio Receiver and HD Radio Tuner |
| Technology | 100% RF CMOS |
| Frequency Range (FM) | 64 MHz to 108 MHz (worldwide) |
| Frequency Range (AM) | 520 kHz to 1.71 MHz (worldwide) |
| Broadcast Standards | AM, FM, RDS, RBDS, HD Radio (HDR) |
| Analog Supply Voltage (VA) | 5 V |
| Digital Supply Voltage (VD) | 3.3 V |
| Additional Band Support | Weather band, shortwave, longwave (variant dependent) |
| Diversity Reception | Dual antenna FM phase diversity (variant dependent) |
| Package | 40-QFN (6x6 mm) |
| Mounting Type | Surface Mount |
Si476 40-qfn (6x6 mm) Pin Configuration Guide
Pin configuration for Si476 (40-qfn (6x6 mm) package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for Si476.
Refer to the datasheet for full pin configuration.
Typical Applications
Si476 is suitable for 6 applications: Automotive Head Units, HD Radio Broadcast Reception, RDS/RBDS Data Services, Weather Band Receivers, Multi-Band Consumer Radios (SW/LW), Dual-Antenna FM Phase Diversity Systems.
Automotive Head Units
The Si476x was engineered specifically for automotive infotainment, where 100% RF CMOS integration delivers OEM-grade receiver quality in a single 40-QFN (6x6 mm) chip. Its worldwide FM coverage of 64-108 MHz and AM coverage of 520 kHz-1.71 MHz allow one design to serve global markets without regional hardware changes. In a head unit, the device sits between the vehicle antenna (via an RF matching network) and the audio DSP, demodulating broadcast audio and streaming RDS/RBDS data over the host interface. Variants with dual-antenna FM phase diversity materially improve multipath rejection in dense urban driving, a key differentiator against consumer tuners. The 5 V analog and 3.3 V digital supplies align directly with standard automotive post-regulator rails.
Recommended
HD Radio Broadcast Reception
For North American automotive and consumer platforms requiring HD Radio (HDR), HDR-capable Si476x family members such as the SI4764-A20-AM provide digital broadcast reception alongside analog AM/FM in the same silicon. The tuner digitizes the FM band signal and decodes the HDR subcarriers, while the on-chip RDS/RBDS processor handles data-service symbols independently of the host. Placing HDR decoding in the tuner IC simplifies the bill of materials versus multi-chip discrete solutions and reduces alignment labor in production. Engineers should budget for the 5 V analog supply current and ensure clean VA decoupling, since HDR demodulation is sensitive to analog supply ripple in the 64-108 MHz receive path.
Recommended
RDS/RBDS Data Services
The Si476x integrates a hardware digital processor for the European RDS and North American RBDS standards, including all required symbol decoding, block synchronization, and error checking. This makes it ideal for radios that display program service names, traffic announcements, and alternative frequencies. Because decoding occurs in silicon, even modest host MCUs can poll RDS groups without real-time constraints, lowering total system cost. The separate VIO1/VIO2 interface supply rails let the RDS data bus connect directly to 3.3 V or lower-voltage host processors without level shifters. Designers should reserve host bandwidth for group polling and implement the manufacturer-recommended interrupt scheme for TA/AF flag handling.
Recommended
Weather Band Receivers
Si476x variants supporting the weather band extend the base tuner beyond AM/FM to NOAA weather broadcast channels, useful in fleet telematics, marine radios, and emergency information terminals sold in North America. The same 40-QFN (6x6 mm) footprint and 5 V/3.3 V supply architecture used for the AM/FM design apply, so a weather-band capable product can reuse the approved PCB layout and simply select the appropriate family MPN. Because weather channels occupy the VHF band adjacent to the 64-108 MHz FM range, the existing FM antenna and matching network typically require only retuning of external components. Confirm band availability for the specific ordering code before finalizing the BOM.
Recommended
Multi-Band Consumer Radios (SW/LW)
Shortwave and longwave variants of the Si476x family enable world-band consumer receivers, emergency radios, and portable multi-band products from the same silicon platform as the automotive design. The worldwide AM band support spanning 520 kHz to 1.71 MHz is the foundation, with SW/LW bands added on qualifying variants - no extra tuner chip is required. The all-CMOS architecture eliminates the manual alignment steps of discrete tuners, which is particularly valuable for high-volume consumer manufacturing where factory alignment cost dominates. Engineers should provide adequate PCB clearance around the AM antenna input and verify sensitivity against the datasheet typical-performance tables for the selected band plan.
Recommended
Dual-Antenna FM Phase Diversity Systems
Si476x variants with dual-antenna FM phase diversity reception address the hardest problem in automotive FM: multipath fading in urban canyons. Two spatially separated antennas feed the tuner, which combines the signals in phase diversity to null interference and maintain audio quality - a capability consumer single-antenna tuners cannot match. The price is a second antenna feed and matching network on the PCB, plus layout care to preserve phase balance between the two receive paths. For OEM platforms targeting premium vehicle segments, this feature measurably reduces dropouts during tunnel exits and dense-building driving, and it operates within the same 5 V/3.3 V supply and host-interface framework as standard variants.
Recommended
Recommended Products Summary
Engineering reference data for Si476 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SI4762-A20-AM | SI4763-A10-GM | SI4764-A20-AM |
|---|---|---|---|---|
| Package | 40-QFN (6x6 mm) | 40-QFN (6x6 mm) - same | 40-QFN (6x6 mm) - same | 40-QFN (6x6 mm) - same |
| Brand | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions |
| FM Frequency Range | 64 MHz to 108 MHz | 64 MHz to 108 MHz | 64 MHz to 108 MHz | 64 MHz to 108 MHz |
| AM Frequency Range | 520 kHz to 1.71 MHz | 520 kHz to 1.71 MHz | 520 kHz to 1.71 MHz | 520 kHz to 1.71 MHz |
| RDS/RBDS | Yes (on-chip processor) | Yes | Yes | Yes |
| HD Radio (HDR) | Family dependent | No | No | Yes |
| Analog Supply (VA) | 5 V | 5 V | 5 V | 5 V |
| Digital Supply (VD) | 3.3 V | 3.3 V | 3.3 V | 3.3 V |
| Silicon Revision | A10/A20 family | A20 | A10 | A20 |
Key Differentiators
- HD Radio support in silicon (vs SI4763-A10-GM)
- Integrated RDS/RBDS hardware decoder (vs SI4762-A20-AM)
- Dual-antenna FM phase diversity available (vs SI4762-A20-AM)
Design Notes
The Si476x requires three distinct supply domains: 5 V analog (VA), 3.3 V digital (VD), plus VIO1/VIO2 interface rails. Decouple VA with a pi network (ferrite bead plus 10 uF bulk and 0.1 uF ceramic close to the pin) because analog supply ripple directly degrades FM sensitivity in the 64-108 MHz band. Sequence VD and VIO before or with VA per the manufacturer power-up recommendations, and keep VIO rails at the host bus voltage to avoid level shifters.
Place the 40-QFN (6x6 mm) device with a solid ground plane under the exposed pad and stitch the thermal/electrical pad to ground with an array of vias - this pad is the primary RF ground return. Keep the FM antenna matching network traces short and 50-ohm minded, and route the AM loop/ferrite antenna connections away from the digital bus. Separate the audio output routing from VD switching currents to preserve low-noise demodulated audio.
Feature sets vary by MPN suffix (A10 vs A20 silicon, GM vs AM ordering codes): HD Radio and phase diversity are only on qualifying variants, so a firmware stack written for an SI4764 may fail on an SI4763. Verify the exact ordering code early, confirm band support (weather/SW/LW) per variant, and validate RDS block-error behaviour on your host before locking the firmware API.
Compliance Information
Current-production Si476x family parts listed at DigiKey/LCSC (e.g., SI4763-A10-GM, SI4762-A20-AMR) are standard RoHS/lead-free surface-mount RF ICs. Verify per-ordering-code compliance certificates on the Skyworks product page.
