AN851 Datasheet, PDF (1/25 Pages) Silicon Laboratories – Si468X SCHEMATICS AND LAYOUT GUIDE

AN851
Si468X SCHEMATICS AND LAYOUT GUIDE
1. Introduction
This document provides the following:
General Si468x design guidelines, which include schematics, layout, and BOM
Si468x AM/AMHD-FM/FMHD-DAB/DAB+ antenna/matching network design guidelines
2. Si468x QFN Schematic and Layout
2.1. Schematic design and component selection
This section shows the minimal schematic and layout options reserved for optimal performance of the Si468x in the
QFN package. Population options are provided to mitigate on-chip VCO radiated emissions, to use analog audio
output, and to operate the Si468x with crystal.
2.1.1. Schematic Design
4
3
2
1
VCORE
VMEM_C
VIO
B
B
J1 is used for FM/DAB Testing
J1
SMA_EDGE
D1 1CM1210
CH1
C1
33pF
L4
18nH
C15
2.7pF
Optional
FM/DAB Matching Option
L2
L1
120nH 22nH
VHFI
VHFSW
1 _NVSSB
2 _NVSCLK
3 INTB
4 _RSTB
5
AMLOOPN 6
AMLOOPP 7
SMODE
LOOPN
LOOPP
8 WHIP
9 _RFREF
10 _VHFI
11 _VHFSW
12 _VA
U1
SI46xx
DBYP 36
VMEM35
VIO ³⁴
DOUT ³³
MISO ³²
MOSI ³¹
SCLK ³⁰
SSB ²⁹
DFS ²⁸
DCLK ²⁷
DIN ²⁶
DIFS ²⁵
C6 C9 C22
8.2pF 2.2nF 1uF
C7
8.2pF
C10
C23
2.2nF 1uF
C8
C11 C24
8.2pF 2.2nF 1uF
VP
VN
2
3
VA
C4
1uF
C3 C2
2.2nF 8.2pF
J8
SMA_EDGE
R57
49.9
T2
1
6
5
3
4
TTBW2010L
1:1
J2
R60 0
R61 0
T1
R56
NP
6
1
4
3
SL755TF01
R62
NP
A
Population Options for AM Front End
Conducted Test
---------------------
Default
Confidential
-R--a--d-i-a--te--d---T-e--s--t-u- ^{sing Loop Antenna}
Populate R56, R62
Remove R60, R61
-R--a--d-i-a--te--d---T-e--s--t-u- ^{sing Ferrite Antenna}
Remove R60, R61, R56, R62
All Material and information contained herein
is confidential and covered under non-disclosure agreement (NDA)
4
AMLOOPN
AMLOOPP
19.2MHZ
X1
XTAL_OUT
Optional
DIAG_A
C5
1uF
Optional
C13
8.2pF
C12
8.2pF
FB5
1000_ohm_Ferrite
1uF
C20
ROUT
FB6
1000_ohm_Ferrite
1uF
C21
LOUT
Optional
DRAWN BY
3
SCALE
1.1
2
SHEET
1 ^of
2
Figure 1. Si468x QFN Schematic Design
A
Silicon Laboratories, Inc.
400 West Cesar Chavez
Austin, Texas 78701 USA
[phone]
TITLE
Si46xx QFN Daughter Card
SIZE
B
DWG NO
13-05-2014_14:12
1
Rev 4.0
Rev. 0.2 11/14
Copyright © 2014 by Silicon Laboratories
AN851