Silicon Laboratories SI4730 - Manual (Page 2)

AM/FM Receiver Copyright © 2010 by Silicon Laboratories 9.17.10
Silicon Laboratories and Silicon Labs are trademarks of Silicon Laboratories Inc.
Other products or brandnames mentioned herein are trademarks or registered trademarks of their respective holders.
Si4730/31-D60
Broadcast AM/FM Radio Receiver
New Si4730/31-D60 Features
FM Multipath Detection and Mitigation
Provides the ability to detect a multipath situation and maintain audio SNR fidelity. Multipath mitigation is
important in RF environments with high signal scatterings such as cities with tall buildings.
FM Hi-Cut Control
Hi-cut control is employed to increase the audio quality during low SNR and/or multipath situations. Hi-cut on
the Si4730/31-D60 improves the sound quality by seamlessly selecting 1 of 7 different audio filters to optimize
SNR versus audio frequency range. The end result is lower noise on weak stations and stations suffering from
multipath.
Advanced Stereo Blend
The Si4730/31-D60 uses RSSI, SNR, and multipath to determine the best blend setting, providing an
enhanced user listening experience. Utilizing these three metrics, stereo blend is optimized to allow for full
stereo in high fidelity situations and a blended or full mono in sub-optimal conditions. Traditional stereo blend
only uses the receive signal strength indicator (RSSI) to blend from stereo to mono.
Auxiliary Input
The optional analog auxiliary input (line-in) eliminates the need for an ADC when using a digital system
architecture. The left and right auxiliary inputs get digitized on-chip. Audio output formats include I2S, Left-
justified, and Right-justified.
Advanced RDS Processor
The Si4731-D60 implements an advanced, high-performance RDS processor for demodulation, symbol
decoding, block synchronization, error detection, and error correction. The advance RDS decoder provides
improved RDS sensitivity, excellent RDS persistence, faster lock, and lower decoder error rates resulting in
acquiring RDS information faster and greater data reliability in low SNR environments.
Smart Tune
The Si4730/31-D60 automatically selects the IF injection side to optimize the SNR. This improves the desired
station reception in areas that have large near-in blockers.
Selected Electrical Specifications
Parameter Symbol Test Condition Min Typ Max Unit
FM Input Frequency f
RF
64 — 108 MHz
AM Input Frequency f
RF
520 — 1710 kHz
FM Sensitivity with 50
 network
(S+N)/N = 26 dB — 1.1 — µV EMF
RDS Sensitivity — 8 — µV EMF
AM Sensitivity (S+N)/N = 26 dB — 25 — µV EMF
Input IP3 |f
2
– f
1
| > 1 MHz; f
0
= 2 x f
1
– f
2
— 105 — dBµV EMF
FM Adjacent Channel Selectivity ±200 kHz — 50 — dB
FM Alternate Channel Selectivity ±400 kHz — 70 — dB
FM Audio Stereo Separation 34 42 — dB
FM Audio S/N — 63 — dB
AM Audio S/N — 56 — dB
AM and FM Audio THD — 0.1 — %