Si4770/Si4777-A20 High-Performance Consumer Electronics Broadcast Radio Receiver and HD Radio Tuner

Si4770/77-A20
H I G H - P ERFORMANCE C ONSUMER E LECTRONICS
B ROADCAST R ADIO R ECEIVER A N D HD R ADIO TUNER
Features









Digital (I2S) Zero-IF AM/FM I/Q
outputs (Si4777 only)
 1.2 to 5 V power supplies
 QFN 40-pin, 6x6x0.85 mm
GPIO2
DACREF
XTAL1
RCLK/
XTAL2
ROUT
LOUT/
MPXOUT
VA
37
36
35
34
33
32
31
1
30
NC/BLEND
2
29
DCLK
FMXIN
3
28
DFS
RFGND
4
27
DOUT
RFREG
5
26
NC/QOUT
FMO
6
25
NC/IOUT
FMI
7
24
NC/IQFS
NC
8
23
NC/IQCLK
NC
9
22
VIO2
AMI
10
21
DBYP
GND PAD
13
14
15
16
17
18
19
20
A0
A1/INTB
NC/DCLK2
NC/DOUT2
RSTB
SDA
SCL
INTB/DFS2
VIO1
VD
Description
NC
FMXIP
12
Boom boxes
 Home theater systems

38
compliant
GPIO1
Pb-free/RoHS
Si4770/77-A20
11
Audio/video receivers
 Consumer electronics
Pin Assignments

Applications

Ordering Information:
See page 49.
39


L/R analog and digital (I2S) audio
outputs
Digital Low-IF architecture
Frequency synthesizer with fully
integrated PLL-VCO
Fully integrated AM/FM front-end
including high performance LNA,
AGC with integrated resistor and
capacitor banks, and RF and IF
peak detectors
Integrated crystal oscillator
40


FMAGC2

AM/FM hi-cut control
 AM lo-cut filter

FMAGC1

Worldwide FM band support
(64–108 MHz)
Worldwide AM band support
(520–1710 kHz)
AM/FM HD Radio support
(Si4777 only)
Comprehensive signal quality
metrics: RSSI, SNR, multipath
interference, frequency offset,
adjacent channel RSSI,
frequency deviation, and image
RSSI
Advanced patented RDS softdecision decoder
Advanced, patented FM channel
equalizer for multipath
interference
Dynamic AM/FM channel
bandwidth control
Programmable AM/FM soft mute
FM stereo-mono blend
FM hi-blend control
Patents pending
The Si4770/77-A20 broadcast receiver and HD Radio tuner (Si4777 only)
employs an advanced, proven digital low-IF architecture to bring
outstanding receiver performance to high-performance consumer
electronics.
Rev. 0.9 6/12
Copyright © 2012 by Silicon Laboratories
Si4770/77-A20
This information applies to a product under development. Its characteristics and specifications are subject to change without notice.
Si4770/77-A20
IQFS
IOUT
QOUT
IQCLK
FMAGC2
FMAGC1
Functional Block Diagram
Si4770/77
ADC
FMXIP
FMXIN
ADC
RFREG
LOUT/
MPXOUT
DAC
ROUT
DSP
IF PKD
RF PKD
DAC
REG
RL
FMO
FMI
LNA
DCLK
DFS
DOUT
0°/90°
RDS
RF PKD
RF PKD
INTB
RSTB
AMI
2
VIO1
Rev. 0.9
SCL
A1
SDA
A0
VIO2
XTAL1
RFGND
CNTRL
ClK
Gen
XTAL2/
RCLK
LNA
Si4770/77-A20
TABLE O F C ONTENTS
Section
Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Typical Application Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3. Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2. Clocking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.3. Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.4. FM Receiver Front-End . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.5. AM Receiver Front-End . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.6. Received Signal Qualifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.7. Digital Audio Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.8. Channel Equalizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.9. Digital ZIF I/Q Interface (Si4777 Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.10. IBOC Blend Mode for HD Radio (Si4777 Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.11. Stereo Audio Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.12. De-emphasis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.13. Analog Audio and FM MPX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.14. Soft Mute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.15. AM/FM Dynamic Bandwidth Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.16. Seek and Valid Station Qualification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.17. AM Hi-Cut Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.18. FM Hi-Cut Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.19. FM Hi-Blend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.20. AM Lo-Cut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
5. RDS/RBDS Advanced Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
6. Programming Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
7. I2C Control Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
7.1. I2C Device Address Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
7.2. I2C Standard Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
8. Reset, Powerup, and Powerdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
9. Pin Descriptions: Si4770/77-A20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
11. Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
12. PCB Land Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
13. Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
13.1. Si4770/77-A20 Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
13.2. Top Marking Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Rev. 0.9
3
Si4770/77-A20
1. Electrical Specifications
Table 1. Recommended Operation Conditions*
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Analog Supply Voltage
VA
—
4.5
5
5.5
V
Digital Supply Voltage
VD
—
2.7
3.3
3.6
V
VIO1
—
1.7
3.3
3.6
V
VIO2
—
1.2
3.3
3.6
V
Interface Supply Voltage
*Note: All minimum and maximum specifications are guaranteed and apply across the recommended operating conditions.
Typical values apply at VD = 3.3 V, VIO1 = 3.3 V, VIO2 = 3.3 V, VA = 5 V, and 25 °C unless otherwise stated. Parameters
are tested in production unless otherwise stated.
Table 2. DC Characteristics
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
671
850
1049
mW
FM Mode
Total Supply Power
VA Supply Current
IVA
121
130
139
mA
VD Supply Current
IVD
47
60
79
mA
VA Supply Power Down
Current
IVA
20
90
170
µA
VD Supply Power Down
Current
IVD
5
20
50
µA
707
900
1100
mW
AM Mode
Total Supply Power
VA Supply Current
IVA
129
140
147
mA
VD Supply Current
IVD
47
60
81
mA
VA Supply Power Down
Current
IVA
20
90
170
µA
VD Supply Power Down
Current
IVD
5
20
50
µA
*Note: See "7. I2C Control Bus" on page 44.
4
Rev. 0.9
Si4770/77-A20
Table 2. DC Characteristics (Continued)
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Interface Supplies
VIO1 Supply Current
IVIO1
0.1
0.5
0.82
mA
VIO2 Supply Current
IVIO2
0.1
0.2
0.5
mA
VIO1 Supply Power Down
Current*
IPD
150
250
420
µA
VIO2 Supply Power Down
Current*
IPD
5
20
150
µA
Inputs Pins SCL, SDA, RSTB, A0, A1
High Level Input Voltage
VIH
0.7 x VIO1
—
—
V
Low Level Input Voltage
VIL
—
—
0.3xVIO1
V
High Level Input Current
IIH
VIN = VI01 = 3.6 V
–10
—
10
µA
Low Level Input Current
IIL
VIN = 0 = V,
VI01 = 3.6 V
–10
—
10
µA
Input Pins DCLK, DFS
High Level Input Voltage
VIH
0.7 x VIO2
—
—
V
Low Level Input Voltage
VIL
—
—
0.3 x VIO2
V
High Level Input Current
IIH
VIN = VI02 = 3.6 V
–10
—
10
µA
Low Level Input Current
IIL
VIN = 0 V,
VI02 = 3.6 V
–10
—
10
µA
2.52
—
—
V
—
—
1.08
V
Input Pins GPIO1, GPIO2
GPIO1 and GPIO2
are internally regulated at 3.6 V
High Level Input Voltage
VIH
Low Level Input Voltage
VIL
High Level Input Current
IIH
VIN = 3.6 V
–10
—
10
μA
Low Level Input Current
IIL
VIN = 0 V
–10
—
10
μA
High Level Output Voltage
VOH
Output is common
drain output with
internal 10 k pullup to VIO1
0.8xVIO1
—
—
V
Low Level Output Voltage
VOL
IOUT = –500 μA
—
—
0.2xVIO1
V
Output Pins INTB
*Note: See "7. I2C Control Bus" on page 44.
Rev. 0.9
5
Si4770/77-A20
Table 2. DC Characteristics (Continued)
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
High Level Output Voltage
VOH
Output is common
drain output with
external 4.7 k
pull-up to VIO1
0.8xVIO1
—
—
V
Low Level Output Voltage
VOL
IOUT = –500 μA
—
—
0.2xVIO1
V
High Level Output Voltage
VOH
GPIO1 and GPIO2
are internally regulated at 3.6 V,
IOUT = +500 μA
2.88
—
—
V
Low Level Output Voltage
VOL
IOUT = –500 μA
—
—
0.72
V
Output Pins SDA
Output Pins GPIO1, GPIO2
Output Pins IQCLK, IQFS, IOUT, QOUT, DFS, DCLK, DOUT
High Level Output Voltage
VOH
IOUT = 500 µA
0.8 x VIO2
—
—
V
Low Level Output Voltage
VOL
IOUT = –500 µA
—
—
0.2 x VIO2
V
*Note: See "7. I2C Control Bus" on page 44.
6
Rev. 0.9
Si4770/77-A20
Table 3. Digital Audio Interface Characteristics*
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
DCLK Input Cycle Time
tCYC: DCLK
70
—
—
ns
DCLK Input Pulse Width
High
tHI: DCLK
0.4 x tCYC:DCLK
—
0.6 x tCYC:DCLK
ns
DCLK Input Pulse Width
Low
tLO: DCLK
0.4 x tCYC:DCLK
—
0.6 x tCYC:DCLK
ns
DFS Setup Time
tSU:DFS
10
—
—
ns
DFS Hold Time
tHD:DFS
5
—
—
ns
DOUT ouTput Delay
tPD:DOUT
0
—
35
ns
—
10
CB
VIO2 < 1.33 V
—
Capacitive Loading
VIO2 > 1.33 V
—
—
15
tHI:DCLK
tLO:DCLK
pF
*Note: Guaranteed by characterization.
tCYC:DCLK
DCLK in
tHD:DFS
tSU:DFS
DFS in
tPD:DOUT
DOUT out
Figure 1. Digital Audio
Rev. 0.9
7
Si4770/77-A20
Table 4. Digital Zero-IF I/Q Interface Characteristics (Si4777 Only)1
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V)
Parameter
Symbol
Min
Typ
Max
Unit
tCYC:IQCLK
0.8 x per
per2
1.2 x per
ns
IQCLK Output Pulse Width High
tHI:IQCLK
0.22 x per
—
0.59 x per
ns
IQCLK Output Pulse Width Low
tLO:IQCLK
0.41 x per
—
0.78 x per
ns
IQFS Output Delay
tPD:IQFS
0
—
(0.5 x per) + 18
ns
IQFS Output Setup to IQCLK
Rise3
tSU:IQFS
(0.5 x per) – 18
—
—
ns
IOUT Output Delay
tPD:IOUT
0
—
(0.5 x per) + 18
ns
QOUT Output Delay
tPD:QOUT
0
—
(0.5 x per) + 18
ns
IOUT Output Setup to IQCLK rise3
tSU:IOUT
(0.5 x per) – 18
—
—
ns
QOUT Output Setup to IQCLK
Rise3
tSU:QOUT
(0.5 x per) – 18
—
—
ns
IQCLK Output Cycle Time
Test
Condition
Notes:
1. Guaranteed by characterization.
2. per is the IQCLK I/Q bit clock period. Refer to Table 15 on page 35 for IQCLK bit clock frequencies.
3. Minimum time the Si4770/77-A20 will produce between valid output and the next rising edge of IQCLK
tCYC:IQCLK Max
tCYC:IQCLK Min
IQCLK out
tHI:IQCLK MIN
tLO:IQCLK MAX
tHI:IQCLK MAX
tLO:IQCLK MIN
tPD:IQFS MAX
tSU:IQFS
tPD:IQFS MIN
IQFS out
tPD:IOUT MAX
tSU:IOUT
tPD:IOUT MIN
IOUT out
tPD:QOUT MAX
tSU:QOUT
tPD:QOUT MIN
QOUT out
Figure 2. Digital Zero-IF I/Q
8
Rev. 0.9
Si4770/77-A20
Table 5. Reference Clock and Crystal Characteristics
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
RCLK Supported
Frequencies
—
36.4
37.8
37.209375
—
MHz
RCLK Frequency
Tolerance
–100
—
100
ppm
100 Hz offset
—
—
–86
dBc/Hz
1 kHz offset
—
—
–101
dBc/Hz
10 kHz offset
—
—
–108
dBc/Hz
≥ 100 kHz offset
—
—
–122
dBc/Hz
—
7
—
pF
400
mVPP
Reference Clock, Pin RCLK
RCLK = 36.4 MHz, 37.8 MHz, 37.209375 MHz
Phase Noise
Input Capacitance
Input Voltage
AC coupling capacitor = 1 µF
Square wave input
AC coupling capacitor = 1 µF
Sine wave input
300
—
900
mVPP
Crystal Frequency
—
36.4
37.8
37.209375
—
MHz
Crystal Frequency
Tolerance
–100
—
100
ppm
5
—
21.8
pF
Crystal Oscillator, Pins XTAL1, XTAL2
Load Capacitance, Programmable, Each Pin to
GND
Rev. 0.9
9
Si4770/77-A20
Table 6. I2C Control Interface Characteristics
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Pins SCL, SDA
SCL Frequency
fSCL
0
—
400
kHz
SCL Low Time
tLOW
1.3
—
—
µs
SCL High Time
tHIGH
0.6
—
—
µs
SCL Input to SDA  Setup
(START)
tSU:STA
0.6
—
—
µs
SCL Input from SDA  Hold
(START)
tHD:STA
0.6
—
—
µs
SDA Input to SCL  Setup
tSU:DAT
100
—
—
ns
SDA Input from SCL Hold
tHD:DAT
0
—
900
ns
SDA Output Delay
tPD:DAT
300
—
900
ns
SCL Input to SDA Setup
(STOP)
tSU:STO
0.6
—
—
µs
STOP to START Time
tBUF
1.3
—
—
µs
SDA Output Fall Time
tf:OUT
—
250
ns
—
300
ns
SDA Input, SCL Rise/Fall
Time
CB
20 + 0.1 ----------1pF
tf:IN, tr:IN
CB
20 + 0.1 ----------1pF
Capacitive Loading
CB
—
—
50
pF
Pulse Width Rejected by
Input Filter
tSP
—
—
50
ns
10
Rev. 0.9
Si4770/77-A20
SCL
SDA
tSU:STA tHD:STA
tLOW
START
tr:IN
tHIGH
tr:IN
tf:IN
tSP
tSU:STO
tBUF
70%
30%
70%
30%
tHD:DAT tSU:DAT
tf:IN,
tf:OUT
tPD:DAT
STOP
START
Figure 3. I2C Control Interface Read and Write Timing Parameters
SCL
SDA
(Write)
Command
7-0
A6-A0, 0
START
SDA
(Read)
ADDRESS + R/W
ACK
ADDRESS + R/W
Figure 4.
I2C
ACK
Status
7-0
A6-A0, 1
START
DATA
Arg1
7-0
ACK
DATA
DATA
ACK
STOP
ACK
STOP
Response
7-0
ACK
DATA
Control Interface Read and Write Timing Diagram
Rev. 0.9
11
Si4770/77-A20
Table 7. FM Receiver Characteristics
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V. Typical values measured at
TAMB = 25 °C, FM modulation (L = R), FMOD = 1 kHz, FDEV = 22.5 kHz, Deemphasis = 75 µsec, RF level = 60 dBµV, and
FRF = 98 MHz in application circuit unless otherwise specified)
Parameter
Min
Typ
Max
Unit
Input Frequency
Test Condition
64
—
108
MHz
Frequency Step
Resolution
10
—
200
kHz
—
—
100
ms
—
1.5
—
ms
At LOUT and ROUT pins
—
20
—
ms
Audio THD <1%,
over-deviation handling enabled
—
150
—
kHz
RF AGC Range
—
40
—
dB
AGC Gain
Resolution3
—
2
—
dB
RF AGC Threshold
Accuracy3
2
—
dB
IF AGC Threshold
Accuracy3
1
—
dB
Powerup Time1,2
RCLK or Crystal = 36.4 MHz, 37.8 MHz,
37.209375 MHz
Tune time1
Seek Time/Channel
Max Frequency
Deviation1
1
Following FM Receiver Specifications Refer to Si4770/77-A20 Application Circuit Input
IP36
Blockers at 400/800 kHz offset
AGC disabled (Max RF gain)
115
117
—
dBµV
Audio SINAD = 26 dB
AGC disabled (Max RF gain)
—
–3.5
–2
dBµV
Image Rejection1
Deviation = 22.5 kHz
65
70
—
dB
Adjacent Channel
Rejection1,6
Audio SINAD = 26 dB
Desired = 40dBµV, FMOD = 1 kHz,
FDEV = 22.5 kHz
Undesired at ±100 kHz offset, FMOD = 400 Hz,
FDEV = 22.5 kHz
63
65
—
dB
Sensitivity6
Notes:
1. Guaranteed by characterization.
2. Measured at TAMB = 25 °C.
3. Guaranteed by design.
4. IP3 measured at the FMXIP and FMXIN pins reflects IP3 for mixer stage and all subsequent downstream blocks.
5. Refer to FM test circuit in Figure 5.
6. No A-weighting. Noise integrated from 30 Hz to 15 kHz for audio SINAD and SNR measurements.
7. Input resistance is software configurable.
8. IP3 measured at the FMI input pin reflects IP3 for FMI LNA stage.
9. RDS Synchronization Persistence is the minimum RF level at which the tuner loses synchronization to the RDS PI code
as the RF level decreases from high to low levels.
10. RDS Synchronization Stability is the minimum RF level at which the tuner achieves synchronization to the RDS PI code
as the RF level increases from low to high levels.
11. Noise integrated from 30 Hz to 120 kHz for audio SINAD and SNR measurements.
12
Rev. 0.9
Si4770/77-A20
Table 7. FM Receiver Characteristics (Continued)
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V. Typical values measured at
TAMB = 25 °C, FM modulation (L = R), FMOD = 1 kHz, FDEV = 22.5 kHz, Deemphasis = 75 µsec, RF level = 60 dBµV, and
FRF = 98 MHz in application circuit unless otherwise specified)
Parameter
Alternate Channel
Rejection6
THD
Mono (S+N)/N6
Test Condition
Min
Typ
Max
Unit
Audio SINAD = 26 dB
Desired = 40 dBµV, FMOD = 1 kHz,
FDEV = 22.5 kHz
Undesired at ±200 kHz offset, FMOD = 400 Hz,
FDEV = 22.5 kHz
65
72
—
dB
FDEV = 75 kHz
—
0.05
0.1
%
66
75
—
dB
Stereo (S+N)/N6
Stereo modulation (L = 1, R = 0),
deviation = 67.5 kHz,
pilot deviation = 6.75 kHz
64
70
—
dB
AM Suppression1
AM: m = 0.3/Fmod = 1 kHz, RF level = 60 dBµV
50
55
—
dB
70
75
80
µsec
45
50
54
µsec
Deviation = 75 kHz
–1
—
1
dB
Stereo Separation
Stereo modulation (L = 1, R = 0),
Deviation = 67.5 kHz, pilot deviation = 6.75 kHz
40
43
—
dB
Stereo THD
Stereo modulation (L = 1, R = 0),
Deviation = 67.5 kHz, pilot deviation = 6.75 kHz
—
0.1
0.2
%
Pilot Signal Rejection1
Stereo modulation (L = 1, R = 0),
Deviation = 67.5 kHz, pilot deviation = 6.75 kHz
—
55
—
dB
f = 2 kHz, RDS BLER < 5%
—
13
14.5
dBµV
RDS Synchronization
Time1
f = 2 kHz
RF input = 60 dBµV
—
70
—
ms
RDS PI Lock Time1
f = 2 kHz
RF input = 60 dBµV
—
85
—
ms
De-Emphasis Time
Constant3
L/R Imbalance
RDS Sensitivity1
Notes:
1. Guaranteed by characterization.
2. Measured at TAMB = 25 °C.
3. Guaranteed by design.
4. IP3 measured at the FMXIP and FMXIN pins reflects IP3 for mixer stage and all subsequent downstream blocks.
5. Refer to FM test circuit in Figure 5.
6. No A-weighting. Noise integrated from 30 Hz to 15 kHz for audio SINAD and SNR measurements.
7. Input resistance is software configurable.
8. IP3 measured at the FMI input pin reflects IP3 for FMI LNA stage.
9. RDS Synchronization Persistence is the minimum RF level at which the tuner loses synchronization to the RDS PI code
as the RF level decreases from high to low levels.
10. RDS Synchronization Stability is the minimum RF level at which the tuner achieves synchronization to the RDS PI code
as the RF level increases from low to high levels.
11. Noise integrated from 30 Hz to 120 kHz for audio SINAD and SNR measurements.
Rev. 0.9
13
Si4770/77-A20
Table 7. FM Receiver Characteristics (Continued)
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V. Typical values measured at
TAMB = 25 °C, FM modulation (L = R), FMOD = 1 kHz, FDEV = 22.5 kHz, Deemphasis = 75 µsec, RF level = 60 dBµV, and
FRF = 98 MHz in application circuit unless otherwise specified)
Parameter
Test Condition
Min
Typ
Max
Unit
1 dB compression point of mixer
—
112
—
dBµV
Mixer Input
Resistance3
—
8
—
k
Mixer Input
Capacitance3
—
6
—
pF
Blockers at 400/800 kHz offset,
Max Gain (AGC disabled)
—
123
—
dBµV
Audio SINAD = 26 dB
Max Gain (AGC disabled)
—
3.5
—
dBµV
FMAGC1 Min
—
2.5
—

FMAGC1 Max
—
800
—

FM Mixer Inputs: Pins FMXIP, FMXIN
Maximum RF Input
Voltage3
IP34,5,6
Sensitivity5,6
FM Resistor Banks: FMAGC1, FMAGC2
—
800
—

FMAGC2 Min
—
2.5
—

FMAGC2 Max
—
800
—

—
800
—

FMI Input
Resistance3,7
—
50
—

FMI Input
Capacitance3
—
2
—
pF
—
15
—
dB
—
0.73
—
—
128
—
FMAGC1 Step Size
FMAGC2 Step Size
Maximum parallel resistance change
Maximum parallel resistance change
FM LNA: Pins FMI, FMO
Single Receiver Mode
FMI Return Loss3
64 MHz < F < 108 MHz
FMI Input Referred
Noise3
FMI LNA IP33,8
Blockers at 400/800 kHz offset, Max Gain
nV/ Hz
dBµV
Notes:
1. Guaranteed by characterization.
2. Measured at TAMB = 25 °C.
3. Guaranteed by design.
4. IP3 measured at the FMXIP and FMXIN pins reflects IP3 for mixer stage and all subsequent downstream blocks.
5. Refer to FM test circuit in Figure 5.
6. No A-weighting. Noise integrated from 30 Hz to 15 kHz for audio SINAD and SNR measurements.
7. Input resistance is software configurable.
8. IP3 measured at the FMI input pin reflects IP3 for FMI LNA stage.
9. RDS Synchronization Persistence is the minimum RF level at which the tuner loses synchronization to the RDS PI code
as the RF level decreases from high to low levels.
10. RDS Synchronization Stability is the minimum RF level at which the tuner achieves synchronization to the RDS PI code
as the RF level increases from low to high levels.
11. Noise integrated from 30 Hz to 120 kHz for audio SINAD and SNR measurements.
14
Rev. 0.9
Si4770/77-A20
Table 7. FM Receiver Characteristics (Continued)
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V. Typical values measured at
TAMB = 25 °C, FM modulation (L = R), FMOD = 1 kHz, FDEV = 22.5 kHz, Deemphasis = 75 µsec, RF level = 60 dBµV, and
FRF = 98 MHz in application circuit unless otherwise specified)
Parameter
Test Condition
Min
Typ
Max
Unit
Nominal FMI to FMO gain = 8 dB,
Source load = 50 
—
125
—

—
2
—
pF
FMI Input
Resistance7,3
—
100
—

FMI Input
Capacitance3
—
1.5
—
pF
—
15
—
dB
—
1.20
—
Blockers at 400/800 kHz offset, Max Gain
—
126
—
dBµV
Nominal FMI to FMO gain = 8dB,
Source load = 50 
—
250
—

—
2
—
pF
FMO Output
Resistance3
FMO Output
Capacitance3
Dual Receiver Mode
FMI Return Loss3
64 MHz < F < 108 MHz
FMI Input Referred
Noise3
FMI LNA IP3
3,8
FMO Output
Resistance3
FMO Output
Capacitance3
nV/ Hz
Audio Outputs: Pins LOUT and ROUT
Audio Frequency
Response Low1,2
±3 dB
—
—
30
Hz
Audio Frequency
Response High1,2
±3 dB
15
—
—
kHz
Output Load
Resistance3
At LOUT and ROUT pins
10 k
—
—

Output Load
Capacitance3
At LOUT and ROUT pins
—
—
50
pF
Output Voltage
Deviation = 22.5 kHz
99
112
125
mVRMS
Power Supply
Rejection Ratio
(PSRR)3
100 Hz ripple on power supply lines.
Ripple voltage = 100 mVPP of power supply
voltage
—
45
—
dB
Notes:
1. Guaranteed by characterization.
2. Measured at TAMB = 25 °C.
3. Guaranteed by design.
4. IP3 measured at the FMXIP and FMXIN pins reflects IP3 for mixer stage and all subsequent downstream blocks.
5. Refer to FM test circuit in Figure 5.
6. No A-weighting. Noise integrated from 30 Hz to 15 kHz for audio SINAD and SNR measurements.
7. Input resistance is software configurable.
8. IP3 measured at the FMI input pin reflects IP3 for FMI LNA stage.
9. RDS Synchronization Persistence is the minimum RF level at which the tuner loses synchronization to the RDS PI code
as the RF level decreases from high to low levels.
10. RDS Synchronization Stability is the minimum RF level at which the tuner achieves synchronization to the RDS PI code
as the RF level increases from low to high levels.
11. Noise integrated from 30 Hz to 120 kHz for audio SINAD and SNR measurements.
Rev. 0.9
15
Si4770/77-A20
Table 7. FM Receiver Characteristics (Continued)
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V. Typical values measured at
TAMB = 25 °C, FM modulation (L = R), FMOD = 1 kHz, FDEV = 22.5 kHz, Deemphasis = 75 µsec, RF level = 60 dBµV, and
FRF = 98 MHz in application circuit unless otherwise specified)
Parameter
Test Condition
Min
Typ
Max
Unit
FRF = 83 MHz, RF level = 65 dBµV,
FDEV = 3 kHz, FMOD = 76 kHz
unless otherwise noted
14
16
—
mVRMS
Output Load Resistance3
—
10
—
k
Output Load Capacitance3
—
50
—
pF
—
45
—
dB
110
—
—
kHz
FM MPX Output: Pins MPXOUT
Output Voltage1
PSRR3
100 Hz ripple on power supply lines.
Ripple voltage = 100 mVPP of power supply voltage
Bandwidth1
Following FM MPX Specifications Refer to Si4770/77-A20 Application Circuit
(S+N)/N1,11
Sensitivity1,11
FRF = 83 MHz, RF level = 65 dBµV,
FDEV = 3 kHz, FMOD = 76 kHz
unless otherwise noted
25
30
—
dB
FRF = 83 MHz, FDEV = 3 kHz, FMOD = 76 kHz
unless otherwise noted,
SINAD = 5 dB
—
19
25
dBµV
Notes:
1. Guaranteed by characterization.
2. Measured at TAMB = 25 °C.
3. Guaranteed by design.
4. IP3 measured at the FMXIP and FMXIN pins reflects IP3 for mixer stage and all subsequent downstream blocks.
5. Refer to FM test circuit in Figure 5.
6. No A-weighting. Noise integrated from 30 Hz to 15 kHz for audio SINAD and SNR measurements.
7. Input resistance is software configurable.
8. IP3 measured at the FMI input pin reflects IP3 for FMI LNA stage.
9. RDS Synchronization Persistence is the minimum RF level at which the tuner loses synchronization to the RDS PI code
as the RF level decreases from high to low levels.
10. RDS Synchronization Stability is the minimum RF level at which the tuner achieves synchronization to the RDS PI code
as the RF level increases from low to high levels.
11. Noise integrated from 30 Hz to 120 kHz for audio SINAD and SNR measurements.
16
Rev. 0.9
Si4770/77-A20
Signal Generator
50 
FMXIP
FMXIN
Si477x
Figure 5. FM Test Circuit for Mixer Input IP3 and Sensitivity Measurement
Table 8. AM Receiver Characteristics
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V. Typical values measured at
TAMB = 25 °C, AM modulation = 30%, FMOD = 1 kHz, RF level = 74 dBµV, and FRF = 1 MHz unless otherwise specified)
Parameter
Min
Typ
Max
Unit
Input Frequency
520
—
1710
kHz
Frequency Step
Resolution
1
—
10
kHz
—
—
100
ms
—
15
—
ms
At LOUT and ROUT pins
—
55
—
ms
Mod = 90%, Fmod = 1 kHz, SINAD = 57 dB
—
93
—
dBµV
68
72
—
dB
Powerup Time1,2
Test Condition
RCLK or Crystal = 36.4 MHz, 37.8 MHz,
37.209375 MHz
Tune Time1
Seek Time/Channel1
Maximum RF Input
Voltage1,2
Image Rejection1,3
Adjacent Channel
Rejection1,3
SINAD = 20 dB
Desired = 40 dBµV, FMOD = 1 kHz, MOD = 30%
Undesired at ±9 kHz offset, FMOD = 400 Hz,
MOD = 30%
57
62
—
dB
Alternate Channel
Rejection1,3
SINAD = 20 dB
Desired = 40dBµV, FMOD = 1 kHz, MOD = 30%
Undesired at ±18 kHz offset, FMOD = 400 Hz,
MOD = 30%
59
62
—
dB
Blockers at 40/80 kHz, AGC disabled (Max gain)
110
120
—
dBµV
IP31,3
Notes:
1. Guaranteed by characterization.
2. Measured at TAMB = 25 °C.
3. No A-weighting. Noise integrated from 30 Hz to 15 kHz for audio SINAD and SNR measurements.
4. Guaranteed by design.
Rev. 0.9
17
Si4770/77-A20
Table 8. AM Receiver Characteristics (Continued)
(TAMB = –40 to 85 °C, VA = 4.5 to 5.5 V, VD = 2.7 to 3.6 V, VIO1 = 1.7 to 3.6 V, VIO2 = 1.2 to 3.6 V. Typical values measured at
TAMB = 25 °C, AM modulation = 30%, FMOD = 1 kHz, RF level = 74 dBµV, and FRF = 1 MHz unless otherwise specified)
Parameter
IP21,3
Test Condition
Min
Typ
Max
Unit
Desired = 700 kHz,
Undesired = 1000 kHz, 1700 kHz
AGC disabled (Max gain)
142
146
—
dBµV
—
50
—
dB
RF AGC Range
AGC Step Resolution
2
dB
RF AGC Threshold
Accuracy4
—
2
—
dB
IF AGC Threshold
Accuracy4
—
2
—
dB
Sensitivity1,3
SINAD = 20 dB, AGC Disabled (Max RF Gain)
—
14
17
dBµV EMF
1,3
Mod = 30%
—
0.1
—
%
Mod = 90%
—
0.2
—
%
Mod = 30%
60
65
—
dB
180
—
540
µH
10k
—
—
Ω
—
—
50
pF
96
108
121
mVRMS
—
45
—
dB
THD
Audio SNR1,3
Antenna Inductance3
Audio Outputs: Pins LOUT and ROUT
Audio Output Resistance
Load4
Audio Output
Capacitance Load4
Single Ended
Audio Output Voltage
PSRR at Audio Output
Pins4
Ripple test should be for 100 Hz ripple on power
supply lines
Ripple voltage = 100 mVPP of power supply voltage
Notes:
1. Guaranteed by characterization.
2. Measured at TAMB = 25 °C.
3. No A-weighting. Noise integrated from 30 Hz to 15 kHz for audio SINAD and SNR measurements.
4. Guaranteed by design.
18
Rev. 0.9
Si4770/77-A20
Table 9. Thermal Conditions
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Ambient Temperature
TAMB
—
–40
25
85
°C
Junction Temperature
TJ
—
—
—
115
°C
Delta from Junction to Ambient*
θJA
—
—
27
—
°C/W
*Note: The θJA is layout-dependent, and, therefore, PCB layout must provide adequate heat-sink capability. The θJA is
specified assuming adequate ground plane.
Table 10. Absolute Maximum Ratings1
Parameter
Symbol
Min
Max
Unit
Analog Supply Voltage
VA
–0.5
5.9
V
Digital Supply Voltage
VD
–0.5
3.9
V
I/O 1 Supply Voltage
VIO1
–0.5
3.9
V
I/O 2 Supply Voltage
VIO2
–0.5
3.9
V
Current2
IIN1
–10
10
µA
I/O 1 Input Voltage2
VIN1
–0.3
VI01 + 0.3
V
I/O 2 Input Current3
IIN2
–10
10
µA
I/O 2 Input Voltage3
VIN2
–0.3
VI02 + 0.3
V
Operating Temperature
TOP
–40
95
°C
Storage Temperature
TSTG
–55
150
°C
AM RF Input Level4
VRFIN
–1
VA + 1
V
AM RF Input Current4
IRFIN
–100
100
mA
VRFIN
–1
1
V
FM RF Input Current5
IRFIN
–100
100
mA
HBM ESD
VHBM
–2
2
kV
MM ESD
I/O 1 Input
FM RF Input Level
5
VMM
–200
200
V
ESD6
VCDM
–500
500
V
CDM ESD7
VCDM
–750
750
V
CDM
Notes:
1. Permanent device damage may occur if the absolute maximum ratings are exceeded. Functional operation should be
restricted to the conditions as specified in the operational sections of this data sheet. Exposure beyond recommended
operating conditions for extended periods may affect device reliability.
2. For input pins SCL, SDA, RSTB, A0, A1, GPIO1, GPIO2.
3. For input pins DCLK and DFS.
4. At RF input pins AM1.
5. At RF input pins FMXIN, FMXIP, FMI, FMAGC1, FMAGC2.
6. All pins.
7. Corner pins.
Rev. 0.9
19
RF
SMA_EDGE
J1
FM ANT
C10
18PF
RF
RF
L2
47NH
RF
C9
62PF
JP1
ESD_DIODE
AIRLOOP ANT
D1
L9
10NH
L3
150NH
3
1
RF
GND
T2
SILABS
SL755TF01
4
5
D3
RF
3
2
C13
0.1UF
RF
L1
220NH
RF
1
2
3
4
5
6
7
8
9
10
NC
AMI
FMXIP
FMXIN
GNDRF
RFREG
FMO
FMI
NC
NC
X1
U1
SI4770/77
VD
NC
DCLK
DFS
DOUT
QOUT
IOUT
IQFS
IQCLK
VIO2
DBYP
30
29
28
27
26
25
24
23
22
21
C3
2.2NF
C1
100PF
C20
10UF
C2
2.2NF
Figure 6. Application Circuit
C7
2.2NF
4
6
A0
A1
1
ESD_DIODE
1NF
C8
RF
T1
1:1
GND_PAD
41
3.2x2.5
40
39
38
37
36
35
34
33
32
31
FMAGC1
FMAGC2
GPIO1
GPIO2
DACREF
XTAL1
XTAL2
ROUT
LOUT
VA
NC
NC
RSTB
SDA
SCL
INTB
VIO1
VD
20
11
12
13
14
15
16
17
18
19
20
C6
10UF
C4
2.2NF
C5 2.2NF
C21
0.1UF
VA
RSTB_1
INTB_1
SCL
SDA
VIO1
VIO2
IQCLK
QOUT
IOUT
IQFS
DOUT
DFS
DCLK
ROUT
LOUT/MPX
Host MCU
Digital IQ/ZIF (Si4777 only)
Digital Audio
Analog Audio/ MPX
Si4770/77-A20
2. Typical Application Schematic
Figure 6 shows the proposed application schematic.
Rev. 0.9
Si4770/77-A20
3. Bill of Materials
Table 11. Si4770/77-A20 Bill of Materials
Item
Qty
Ref
Package
1
1
T2
2
1
3
Value
Mfr
Part Number
Transformer, Thru-hole
Silicon Laboratories
SL755TF01
T1
BALUN, 1:1, Toko
Toko
458PT1566
2
C13, C21
CAP, SM, 0402
0.1 µF
Murata
GRM155R71A204KA01D
5
1
C1
CAP, SM, 0402
100 pF
Murata
GRM1555C1H101JZ01
6
1
C10
CAP, SM, 0402
18 pF
Murata
GRM1555C1H180JZ01
7
1
C8
CAP, SM, 0402
1 nF
Murata
GRM155R61H102KA01
8
5
C2, C3,
C4, C5, C7
CAP, SM, 0402
2.2 nF
Murata
GRM155R71H222KA01
9
1
C9
CAP, SM, 0402
62 pF
Murata
GRM1555C1H620JD01
10
2
C6, C20
CAP, SM, 0603
10 µF
Digikey
490-3896-2-ND
11
1
J1
CONN, SMA, Edgemount
AEP Connectors
12
1
JP1
CONN, TH, HEADER,
.100 PITCH,1X2
Samtec
HTSW-101-07-G-D
13
2
D1, D3
ESD Protector, SM
TE Connectivity
PESD0402-140
14
1
U1
IC, SM, Si4770/77-A20,
QFN40
Silicon Laboratories
Si4770/77
15
1
L9
IND, SM, 0603
10 nH
Murata
16
1
L3
IND, SM, 0603
150 nH
Murata
LQW18ANR15G00
17
1
L1
IND, SM, 0603
220 nH
Murata
LQW18ANR22G00
18
1
L2
IND, SM, 0603
47 nH
Murata
LQW18AN47NG00
21
1
X1
XTAL, SM, 3.2 x 2.5 mm
See Table 12
See Table 12
See Table 12
Rev. 0.9
21
Si4770/77-A20
Table 12. Crystal Options
Frequency
(MHz)
Mfr
Series
P/N
36.400000
NDK
NX3225SA
EXS00A-CS02420
37.800000
NDK
NX3225SA
EXS00A-CS02421
37.209375
NDK
NX3225SA
EXS00A-CS02422
36.400000
TaiSaw
SMD 3.2x2.5 36.4 MHz Crystal Unit
TZ1514A
37.800000
TaiSaw
SMD 3.2x2.5 37.8 MHz Crystal Unit
TZ1517A
37.209375
TaiSaw
SMD 3.2x2.5 37.209375 MHz Crystal Unit
TZ1522A
36.400000
Jauch
JXE115
Q36,40-JAS32P4-12-10/20T1-LF
37.800000
Jauch
JXE115
Q37,80-JAS32P4-12-10/20T1-LF
37.209375
Jauch
JXE115
Q37,209375-JAS32P4-12-10/
20-T1-LF
36.400000
Epson Toyocom
TSX-3225
OUTD-2B-0541
37.800000
Epson Toyocom
TSX-3225
OUTD-2B-0541
37.209375
Epson Toyocom
TSX-3225
OUTD-2B-0541
22
Rev. 0.9
Si4770/77-A20
4. Functional Description
IQFS
IOUT
QOUT
IQCLK
FMAGC2
FMAGC1
4.1. Overview
Si4770/77
ADC
FMXIP
FMXIN
ADC
RFREG
LOUT/
MPXOUT
DAC
ROUT
DSP
IF PKD
RF PKD
DAC
REG
RL
FMO
FMI
LNA
DCLK
DFS
DOUT
0°/90°
RDS
RF PKD
RF PKD
INTB
RSTB
AMI
LNA
CNTRL
ClK
Gen
RFGND
VIO1
SCL
A1
SDA
A0
XTAL1
XTAL2/
RCLK
VIO2
Figure 7. Si4770/77-A20 Block Diagram
The Si4770/77-A20 radio receiver family employs 100%
RF CMOS technology to bring outstanding receiver
performance to the consumer electronics industry. The
Si4770/77-A20 receiver family supports worldwide radio
reception. The Si4770/77-A20 incorporates a digital preprocessor for the European Radio Data System (RDS)
and the North American Radio Broadcast Data System
(RBDS) including all required symbol decoding, block
synchronization, error detection, and error correction
functions. The Si4777 supports AM/FM HD radio
channel reception with digital (I2S) Zero-IF (ZIF) I/Q
outputs for interface to an HD radio processor.
The family leverages Silicon Laboratories’ patented lowIF digital architecture, delivering superior RF
performance and interference rejection. The low-IF
architecture delivers superior performance while
integrating the great majority of external components
required by competing solutions.
The proven digital techniques provide excellent
sensitivity in weak signal environments and superb
selectivity and intermodulation immunity in strong signal
environments. The solution offers dynamic AM/FM
channel bandwidth control, auto-calibrated digital
tuning, and proven AM/FM seek functionality based on
multiple signal quality and band parameters. The family
offers highly flexible and advanced audio processing
including programmable softmute, FM stereo-mono
blend, dynamic AM/FM channel bandwidth, AM/FM hicut, FM hi-blend, and AM lo-cut filters. In addition, the
Si4770/77-A20 provides an integrated clock oscillator or
accepts a reference clock and an I2C-compatible, 2-wire
control interface. The Si4770/77-A20 receiver system
specifies a minimal bill of materials, resulting in a small
board space requirement and making the solution ideal
for any consumer electronics application from single
tuner radios to multiple tuner radios.
Rev. 0.9
23
Si4770/77-A20
24
RDS
Analog MPX
(VICS/DARC)



Si4777
AM/FM RDS,
VICS, HD Tuner




Rev. 0.9


IR Cal
MW
(520–1710 kHz)

Channel EQ
FM
(64–108 MHz)
AM/FM RDS,
VICS
Digital ZIF
(HD/DRM)
Description
Si4770
IBOC Blend
Part Number
Table 13. Part Number Descriptions




Si4770/77-A20
4.2. Clocking
4.3. Tuning
The Si4770/77-A20 generates all internal clocking from
an external crystal using an on-chip oscillator or an
external programmable reference clock. The reference
clock of Si4770/77-A20 is a sinusoidal or rectangular
clock provided by an external source on pin RCLK. The
supported crystal and external clock source frequencies
are selected frequencies in the 36–38 MHz range.
The Si4770/77-A20 includes a complete on-chip PLLVCO frequency synthesizer to generate the quadrature
LO input to the image-reject AM and FM mixers. The
Si4770/77-A20 employs a single-conversion mix (down
conversion) to a fixed low IF center frequency. An
innovative high-performance image reject mixer
architecture allows for IF center frequencies below
300 kHz, thereby eliminating ceramic filters required in
10.7 MHz IF tuner architectures. The tune command
automatically programs the LO frequency to the center
of the desired channel plus (minus) the output center IF
frequency when using a high-side (low-side) mix. The
Si4770/77-A20 supports 50, 100, or 200 kHz channel
spacing for FM, 9 or 10 kHz for AM.
XTAL1
CLK
CLK
XTAL2
Si477x
Audio Receiver 1
XTAL2
XTAL1
The power up command enables the selection of an
external crystal or reference clock. The reference clock
and/or crystal accuracy should be ±100 ppm. In a multireceiver system, a single crystal can be shared between
all Si4770/77-A20 receivers. The Si4770/77-A20 family
features programmable loading capacitors for the onchip crystal oscillator, eliminating external loading
capacitors.
Si477x
Audio Receiver 2
Figure 8. Xtal Share between Two Tuners
Rev. 0.9
25
Si4770/77-A20
4.4. FM Receiver Front-End
An advanced AGC on the Si4770/77-A20 is
implemented with the use of internal RF peak and IF
peak detectors with programmable thresholds (trip
points). The AGC adjusts the resistor values
automatically. Attack and release rates for the AGC are
programmable, providing flexible fast attack and slow
release AGC performance.
For cost-effective performance and superior FM
sensitivity, the antenna output can be received on the
FMI pin (Figure 9). The FM band can be received on the
FMI pin via an input coupling network. This input
coupling network isolates the FM band for best
performance. An internal LNA provides gain for the
signal. The LNA output is routed externally to the FM
mixer input pins. The LNA gain is regulated with an
internal voltage regulator supply via an internal resistor
bank, RL. The AGC circuit automatically controls the
LNA gain, resistor banks FMAGC1, FMAGC2, and RL to
optimize sensitivity and strong signal handling.
FMXIP
RF Pkd
FMXIN
RFREG
FMO
FMAGC2
FMAGC1
RF Pkd
FMXIN
50 
FMI
FMI
LNA
RF Pkd
Si477x
Figure 10. Conceptual Illustration of the
Lowest-Cost Configuration
4.4.1. FMI LNA for FM Loop-Through Usage
In dual receiver applications, two receivers (Figure 11)
can be attached to a single antenna. The dual receiver
solution allows for independent radio station listening in
different rooms.
Reg
LNA
RF Pkd
Si477x
Figure 9. Conceptual Illustration of the Use of
the FMI LNA for Cost-Optimized and Superior
FM Sensitivity Performance
Cost can be further reduced by eliminating the 1:1 balun
and directly interfacing the signal to the FM mixer by
programming the mixer for single-ended input mode
(Figure 10). The trade-off is a drop in linearity of 6 dBµV
in IP3.
26
RL
50 
RL
FMO
Reg
The FMI LNA input impedance is software-configurable
and provides two options: 50  and 100 . Configuring
the input impedance for 100  facilitates a Si4770/77A20 receiver 1 and the Si4770/77-A20 receiver 2 to be
interfaced to the antenna output in parallel, providing a
matched 50  input impedance. AGC is coordinated
between both receivers whereby the resistor banks,
FMAGC1, FMAGC2, and RL, from one receiver are
used to optimize sensitivity and strong signal handling.
FMXIP
RFREG
FMAGC2
FMAGC1
The Si4770/77-A20 provides a very flexible front-end
interface to accommodate a wide range of applications
from cost-sensitive to high-performance.
Rev. 0.9
Si4770/77-A20
4.5. AM Receiver Front-End
FMAGC2
FMAGC1
The Si4770/77-A20 contains an integrated LNA,
providing an AM receive chain from antenna to audio
out. There are few external components and no manual
alignment required. The AM signal is received on the
AMI pin. An advanced AGC on the Si4770/77-A20 is
implemented with the use of internal RF peak and IF
peak detectors with programmable thresholds (trip
points). Attack and release rates for the AGC are
programmable providing flexible fast attack and slow
release AGC performance.
FMXIP
RF Pkd
FMXIN
RFREG
Reg
The Si4770/77-A20 provides highly-accurate digital AM
tuning without factory adjustments. To offer maximum
flexibility, the receiver supports a wide range of ferrite
loop sticks from 180~688 µH. An air loop antenna is
supported by using a transformer to increase the
effective inductance of the air loop. Using a 1:5 turn
ratio inductor, the inductance is increased by 25 times
and easily supports all typical AM air loop antennas
which generally vary between 10 and 20 µH.
RL
50 
LNA
FMO
100 
FMI
RF Pkd
Si477x
FMXIP
RF Pkd
FMXIN
RFREG
Reg
RL
FMO
100 
FMI
LNA
RF Pkd
Si477x
Figure 11. Conceptual Illustration of Si4770/77A20 Receivers Interfaced to a Single Antenna
Using the FMI LNA in Loop-Through Mode
Rev. 0.9
27
Si4770/77-A20
4.6. Received Signal Qualifiers
4.7.1. Audio Data Formats
A tuned signal's quality can vary with the environmental
conditions, time of day, and geographical location
among many other factors. To adequately manage the
audio output and avoid unpleasant audible effects to the
end-user, the Si4770/77-A20 monitors and provides
indicators of signal quality, allowing the on-chip DSP
and host processor (if required) to perform signal
processing. The Si4770/77-A20 monitors and reports a
set of industry-standard signal quality metrics including
on-channel RSSI, adjacent channel RSSI (100 kHz and
200 kHz), image RSSI, SNR, multi-path interference on
FM signal, ultra-sonic noise, and FM pilot detection. As
with other Si4770/77-A20 features, how these variables
are used to improve audio performance can be left to
the Silicon Labs on-chip algorithms (recommended), or
they can be brought out for host-processor instructions.
4.7. Digital Audio Interface
The digital audio 3-pin interface consists of data serial
lines containing audio data, a bit clock, and a word
frame for left and right channel data. The digital audio
interface operates in slave mode and supports five
different audio data formats:





I2S Audio
Left-Justified Audio
Right-Justified Audio
DSP Audio
DSP Left-Justified Audio
In I2S format, by default the MSB is captured on the
second rising edge of DCLK following each DFS
transition. The remaining bits of the word are sent in
order, down to the LSB. The left channel is transferred
first when the DFS is low, and the right channel is
transferred when the DFS is high.
In Left-Justified format, by default, the MSB is captured
on the first rising edge of DCLK following each DFS
transition. The remaining bits of the word are sent in
order, down to the LSB. The left channel is transferred
first when the DFS is high, and the right channel is
transferred when the DFS is low.
In Right-Justified format, by default, the LSB is captured
on the last rising edge of DCLK in each valid DFS
interval. The left channel is transferred first when the
DFS is high, and the right channel is transferred when
the DFS is low.
In DSP format, the DFS becomes a pulse with a width of
one DCLK period. The left channel is transferred first,
followed right away by the right channel. There are two
options in transferring the digital audio data in DSP
format; the MSB of the left channel can be transferred
on the first rising edge of DCLK following the DFS pulse
(left-justified DSP format) or on the second rising edge.
In all audio formats, depending on the word size, DCLK
frequency, and sample rates, there may be unused
DCLK cycles after the LSB of each word before the next
DFS transition and MSB of the next word. In addition, if
preferred, the user can configure the MSB to be
captured on the falling edge of DCLK via properties.
The number of audio bits can be configured for 8, 16,
20, or 24 bits.
4.7.2. Audio Sample Rates
The device supports a number of industry-standard
sampling rates including 32, 40, 44.1, and 48 kHz.
28
Rev. 0.9
Rev. 0.9
DOUT
DFS
DCLK
DOUT
DFS
DCLK
I2S
DOUT
DFS
DCLK
MSB
1
MSB
1
2
MSB
1
2
3
1 DCLK
2
3
n-1
n
LSB
n-1
LSB
n
MSB
1
Figure 12. I2S Audio Format
n-2
2
MSB
1
1 DCLK
n-1
LSB
n
1
MSB
Figure 14. Right-Justified Audio Format
n-2
Figure 13. Left-Justified Audio Format
LEFT CHANNEL
n-2
LEFT CHANNEL
3
LEFT CHANNEL
2
3
2
n-2
3
RIGHT CHANNEL
n-2
RIGHT CHANNEL
3
RIGHT CHANNEL
n-2
n-1
n-1
n
n-1
LSB
n
LSB
n
LSB
Si4770/77-A20
29
30
DOUT
(MSB at 1st rising edge)
DFS
DCLK
DOUT
(MSB at 2nd rising edge)
DFS
DCLK
1 DCLK
1
MSB
1
2
MSB
3
2
n-2
n-1
n
LSB
1
MSB
1
MSB
n
LSB
2
3
2
3
n-2
n-1
n-2
RIGHT CHANNEL
RIGHT CHANNEL
Figure 16. DSP Left-Justified Audio Format
n-2
n-1
Figure 15. DSP Audio Format
LEFT CHANNEL
3
LEFT CHANNEL
LSB
n
n-1
n
LSB
Si4770/77-A20
Rev. 0.9
Si4770/77-A20
4.8. Channel Equalizer
4.9.1. ZIF I/Q Data Formats
The Si4770/77-A20 supports advanced FM multi-path
channel equalization. Multi-path interference results in
fading of the FM signal at the receiver. Frequency
selective fading causes different frequencies of an input
signal to be attenuated and phase shifted differently in a
channel. Frequency selective fading gives rise to
notches in the frequency response of the channel. The
Si4770/77-A20 channel equalizer performs blind
equalization utilizing proprietary constant modulus
algorithm (CMA) to restore the flat response of the
channel.
4.9. Digital ZIF I/Q Interface
(Si4777 Only)
The digital ZIF I/Q output can provide the down
converted channelized AM/FM signal at baseband to a
third-party processor for AM/FM HD radio processor for
IBOC signal processing. The Si4777 provide a 500 kHz
BW signal for FM IBOC signal processing and a 30 kHz
BW signal for AM IBOC signal processing. The ZIF I/Q
4-pin interface consists of two data serial lines
containing I and Q data, a bit clock, and a word frame
for each data sample. The interface operates in master
mode and supports five different data formats:





I2S ZIF
Left-Justified ZIF
Right-Justified ZIF
DSP ZIF
DSP Left-Justified ZIF
In I2S format, by default, the MSB is captured on the
second rising edge of IQCLK following each IQFS
transition. The remaining bits of the word are sent in
order, down to the LSB.
In Left-Justified format, by default, the MSB is captured
on the first rising edge of IQCLK following each IQFS
transition. The remaining bits of the word are sent in
order, down to the LSB.
In Right-Justified format, by default, the LSB is captured
on the last rising edge of IQCLK in each valid IQFS
interval.
In DSP format, the IQFS becomes a pulse with a width
of 1 IQCLK period. There are two options in transferring
the digital baseband I/Q data in DSP format: the MSB of
I and Q data can be transferred on the first rising edge
of IQCLK following the IQFS pulse (left-justified DSP
format) or on the second rising edge.
In all data formats, depending on the word size, IQCLK
frequency, and sample rates, there may be unused
IQCLK cycles after the LSB of each word before the
next IQFS transition and MSB of the next word. In
addition, if preferred, the user can configure the MSB to
be captured on the falling edge of IQCLK via properties.
The number of baseband I/Q bits is configured for 16
bits.
Table 14. ZIF I/Q Interface Description
Pin
Description
IOUT
16-bit baseband I word
QOUT
16-bit baseband Q word
IQFS
Word frame sync for I and Q words
IQCLK
Bit clock for I and Q data
Rev. 0.9
31
32
2
3
Rev. 0.9
QOUT
MSB
1
MSB
2
3
n-2
n-2
1
3
3
IOUT
2
2
Sample n
MSB
1
MSB
1
1 IQCLK
Sample n
IQFS
IQCLK
QOUT
IOUT
IQFS
IQCLK
LSB
n
LSB
n
2
n-1
n-1
LSB
n
LSB
n
1
MSB
1
MSB
1
2
2
MSB
1
MSB
Figure 17. I S ZIF Format
n-1
n-1
Figure 18. Left-Justified ZIF Format
n-2
n-2
1 IQCLK
2
2
3
3
3
3
n-2
n-2
Sample n+1
Sample n+1
n-2
n-2
n-1
n-1
n-1
n-1
n
n
LSB
n
LSB
LSB
n
LSB
Si4770/77-A20
Rev. 0.9
IQFS
IQCLK
QOUT
(MSB at 2nd rising edge)
IOUT
(MSB at 2nd rising edge)
QOUT
IOUT
IQFS
IQCLK
1 IQCLK
1 IQCLK
MSB
1
MSB
1
2
2
MSB
1
MSB
1
3
3
2
2
Sample n
3
3
n-1
n-1
LSB
n
LSB
n
MSB
1
MSB
1
n-2
n-2
n-1
n-1
LSB
n
LSB
n
MSB
1
MSB
1
Figure 20. DSP ZIF Format
Sample n
Sample n
2
2
Figure 19. Right-Justified ZIF Format
n-2
n-2
2
2
3
3
3
3
Sample n+1
Sample n+1
Sample n+1
n-2
n-2
n-1
n-1
n-2
n-2
LSB
n
LSB
n
n-1
n-1
LSB
n
LSB
n
Si4770/77-A20
33
34
QOUT
(MSB at 1st rising edge)
IOUT
(MSB at 1st rising edge)
IQFS
IQCLK
1
MSB
1
MSB
2
2
3
3
n-2
n-2
n-1
n-1
n
LSB
n
LSB
1
MSB
1
MSB
2
2
3
3
Figure 21. DSP Left-Justified ZIF Format
Sample n
Sample n
Sample n+1
Sample n+1
n-2
n-2
n-1
n-1
n
LSB
n
LSB
Si4770/77-A20
Rev. 0.9
Si4770/77-A20
4.9.2. ZIF I/Q Sample Rates and Clocking Requirements
The device supports a number of industry-standard sampling rates including 650, 675, and 744.1875 kHz.
The external crystal and/or reference clock frequency must be the following to support the following ZIF I/Q
samples rates for interface to an HD radio demodulator/decoder or DSP.
Table 15. Crystal/Reference Clock Frequency Requirements for the ZIF I/Q Sample Rates and
Bit Clock Rates Supported
RCLK/XTAL
Frequency (MHz)
36.4000
37.8000
37.209375
IQFS ZIF I/Q
Sample Rate (kHz)
IQCLK
I/Q Bit Clock (MHz)
Broadcast Reception
Modes
650.0000
10.4000
AM/FM HD-Radio
325.0000
5.2000
FM Analog
40.6250
2.2750
AM Analog/HD-Radio
675.0000
10.8000
AM/FM HD-Radio
337.5000
5.4000
FM Analog
42.1875
2.3625
AM Analog/HD-Radio
744.1875
14.88375
AM/FM HD-Radio
372.0938
7.4419
FM Analog
46.5117
1.8605
AM Analog/HD-Radio
Rev. 0.9
35
Si4770/77-A20
4.10. IBOC Blend Mode for HD Radio
(Si4777 Only)
For HD-Radio reception IBOC blend is supported on the
Si4777. This feature supports the ability to blend
between analog and digital audio. When the bit error
rate (BER) of the HD-Radio digital signal falls below a
predefined threshold (set by the HD-Radio
demodulator) and the digital audio fades out, the analog
audio is blended in. This prevents the received audio
from muting when the digital signal is lost. The audio will
"blend to digital" upon reacquisition of the digital signal.
Figure 22 illustrates the system implementation with a
third party HD-Radio demodulator. ZIF I/Q data is output
to the HD-Radio demodulator. The HD-Radio
demodulator demodulates and decodes the received
HD-Radio signal. It outputs digital audio (I2S three-wire
mode) to the Si4777 where the IBOC blend is
performed. An on-chip asynchronous resampling
converter (ASRC) allows the Si4777 to be slaved to the
HD-Radio demodulator digital audio output at any
sample rate from 32 kHz to 48 kHz.
The HD-R demodulator sends a 1-bit "BLEND" signal to
the Silicon Labs tuner. When this signal is "1", the
Si4777 initiates a crossover from full AM/FM analog
audio into full HD-R audio following a time ramp at a
programmable ramp rate. This process continues until
HD-R audio is fully blended to analog or until the
BLEND bit becomes a "0". When the BLEND bit is "0",
the reverse crossover occurs (crossover from HD-R to
AM/FM analog following a programmable ramp rate).
This process continues until AM/FM is fully blended or
until BLEND becomes "1".
The blended audio can be output on the analog output
pins, LOUT and ROUT and/or a digital audio port to a
third party audio DSP.
An on-chip asynchronous re-sampling converter
(ASRC) allows the Si4777 to be slaved to the Audio
DSP’s digital frame sync and bit clock from 32 kHz to
48 kHz.
Audio level alignment and calibration is implemented in
the Si4777 by multiplying the input HD-R audio signal
by a scaling constant (determined at manufacturing time
in the factory) and a dynamic constant that is HD-R
station-dependent. The dynamic constant is determined
by the HD-R demodulator during reception and is
relayed to the Si4777 by the host controller for the
blend.
4.10.1. IBOC Blend and I2C Device Address
Selection
In applications not requiring HD-Radio reception and
IBOC blend, with the Si4777, two I2C device addresses,
A0 and A1 (pins 11 and 12), are available, allowing up
to four Si4777 receivers to share the same I2C bus (see
"7. I2C Control Bus" on page 44). However in utilizing
IBOC blend for HD-radio reception on the Si4777, only
one device address A0 (pin 11) is available. Pin 12 is
repurposed for the Interrupt output INTB, whilst Pin 18
is repurposed for the digital audio clock input DFS2.
The 7-bit device address consists of a fixed part (6
MSBs), followed by a programmable 1-bit part. The LSB
of the device address signals whether a read or write
I2C operation occurs. The voltage on the A0 pin is used
to set the programmable 1-bit part of the device
address. The A0 pin is tied to ground and or is left to
float for address selection. The various I2C device
addresses can be selected as summarized in Table 16.
Table 16. I2C Device Address Selection in IBOC Blend Mode for Si4777
36
Device Address [6…1]
Device Address [0]
A0 Voltage (Pin connection)
110001
1
VIO1
110001
0
GND
Rev. 0.9
Si4770/77-A20
HD Radio Demod
QOUT (Pin 26)
IOUT (Pin 25)
IQFS (Pin24)
IQCLK (Pin 23)
Digital I/Q ZIF
(I2S)
Demod
Audio /Data
Decoders
Master
4-wire mode
Master
Si4777
AM/FM Analog demodulation
Weak signal processing
IBOC
blend
ASRC
PLL
AM/FM
audio
Blended
audio
BLEND (Pin 30)
DCLK (Pin 29)
Blend Flag
Digital bit clock
DFS (Pin 28)
DIN (Pin 27)
Digital frame sync
HD audio (MP1)
ASRC
DOUT2 (Pin 14)
DCLK2 (Pin 13)
DFS2 (Pin 18)
Blended audio
Digital bit clock
Digital frame sync
Audio
processing
X
3-wire mode
DSP
Master
Figure 22. System Implementation of HD-Radio Reception with IBOC Blend on the Si4777
Rev. 0.9
37
Si4770/77-A20
VA
33
32
31
36
ROUT
37
LOUT/
MPXOUT
DACREF
38
34
GPIO2
35
GPIO1
39
XTAL1
FMAGC2
40
RCLK/
XTAL2
FMAGC1
NC
1
30
BLEND
FMXIP
2
29
DCLK
FMXIN
3
28
DFS
RFGND
4
27
DIN
RFREG
5
26
QOUT
FMO
6
25
IOUT
FMI
7
24
IQFS
NC
8
23
IQCLK
NC
9
22
VIO2
AMI
10
21
DBYP
GND PAD
13
14
15
16
17
18
19
INTB
DCLK2
DOUT2
RSTB
SDA
SCL
DFS2
VIO1
VD
12
A0
20
11
Figure 23. Si4777 Pin Descriptions for IBOC Blend Mode
Table 17. Pin Descriptions for Si4777 for IBOC Blend Mode
Pin Number
Name
I/O
1
NC
I
No connect: Leave floating
2
FMXIP
I
Balanced input to FM mixer (positive)
3
FMXIN
I
Balanced input to FM mixer (negative)
4
RFGND
5
RFREG
O
FM LNA regulator
6
FMO
O
FM LNA output
7
FMI
I
FM LNA input
8
NC
No connect: Leave floating
9
NC
No connect: Leave floating
10
AMI
I
AM single-ended input
11
A0
I
I2C Address 0
12
INTB
O
Interrupt active low (Si4777 for IBOC blend mode)
13
DCLK2
I
Digital audio bit clock input (Si4777 for IBOC blend mode)
14
DOUT2
O
Digital audio output (Si4777 for IBOC blend mode)
38
Description
RF Ground
Rev. 0.9
Si4770/77-A20
Table 17. Pin Descriptions for Si4777 for IBOC Blend Mode (Continued)
Pin Number
Name
I/O
Description
15
RSTB
I
16
SDA
17
SCL
I
I2C clock
18
DFS2
I
Digital audio bit clock input (Si4777 for IBOC blend mode)
19
VIO1
S
Host I/O Supply Voltage (all pads except digital audio and I/Q)
20
VD
S
Digital Voltage Supply
21
DBYP
I
Digital bypass to Ground
22
VIO2
S
Digital audio and I/Q interface supply voltage
23
IQCLK
O
ZIF I/Q bit clock output (Si4777)
24
IQFS
O
ZIF I/Q frame sync output (Si4777)
25
IOUT
O
ZIF I data output (Si4777)
26
QOUT
O
ZIF Q data output (Si4777)
27
DIN
I
Digital audio data input (Si4777 for IBOC blend mode)
28
DFS
I
Digital audio frame sync input
29
DCLK
I
Digital audio bit clock input
30
BLEND
I
Blend Flag Control
31
VA
S
Analog Voltage Supply
32
LOUT/ MPXOUT
O
Left audio line out / FM MPX output
33
ROUT
O
Right audio line out
34
XTAL2/RCLK
I
Crystal oscillator input/Reference clock input
35
XTAL1
O
Crystal oscillator output
36
DACREF
I
Voltage Reference for analog outputs
37
GPIO2
I/O General-purpose input/output
38
GPIO1
I/O General-purpose input/output
39
FMAGC2
I
FM automatic gain control 2
40
FMAGC1
I
FM automatic gain control 1
PDL
GND PAD
I
Ground. Reference ground
Global Chip Reset
I/O I2C Data input/output
Rev. 0.9
39
Si4770/77-A20
4.11.1. Stereo Decoder
The output of the FM demodulator is a stereo
multiplexed (MPX) signal. The MPX standard was
developed in 1961, and is used worldwide. Today's
MPX signal format consists of left + right (L+R) audio,
left – right (L–R) audio, a 19 kHz pilot tone, and RDS/
RBDS data as shown in Figure 24.
The Si4770/77-A20's integrated stereo decoder
automatically decodes the MPX signal using DSP
techniques. The 0 to 15 kHz (L+R) signal is the mono
output of the FM tuner. Stereo is generated from the
(L+R), (L–R), and a 19 kHz pilot tone. The pilot tone is
used as a reference to recover the (L–R) signal. Output
left and right channels are obtained by adding and
subtracting the (L+R) and (L–R) signals respectively.
Modulation Level
4.11. Stereo Audio Processing
4.11.2. Stereo-Mono Blending
Mono Audio
Left + Right
0
Stereo
Pilot
Stereo Audio
Left - Right
15 19 23
38
RDS/
RBDS
53
Frequency (kHz)
Figure 24. MPX Signal Spectrum
57
Adaptive noise suppression is employed to gradually
combine the stereo left and right audio channels to a
mono (L+R) audio signal as the signal quality degrades
to maintain optimum sound fidelity under varying
reception conditions. Signal metrics such as on-channel
RSSI, ultra-sonic noise (USN), and multi-path
interference are monitored simultaneously in forcing a
blend from stereo to mono. The metric, reflecting the
poorest signal quality, takes priority and the stereo
signal is blended appropriately. The thresholds for
activating stereo-mono blend are programmable, as are
the levels for a fully blended state. The attack and decay
rates for each metric are programmable. The pilot
detection metric is additionally available for read-out.
Stereo thld
SNR (dB)
Mono thld
Stereo thld
RSSI (dBuV)
Mono thld
Mono thld
Multi-path %
Stereo thld
T< Trelease
Stereo
Blend level
Mono
Figure 25. Conceptual Illustration of Stereo-Mono Blend
40
Rev. 0.9
Si4770/77-A20
4.12. De-emphasis
4.16. Seek and Valid Station Qualification
Pre-emphasis and de-emphasis is a technique used by
FM broadcasters to improve the signal-to-noise ratio of
FM receivers by reducing the effects of high-frequency
interference and noise. When the FM signal is
transmitted, a pre-emphasis filter is applied to
accentuate the high audio frequencies. The Si4770/77A20 incorporate a de-emphasis filter which attenuates
high frequencies to restore a flat frequency response.
Two time constants are used in various regions. The deemphasis time constant is programmable to 50 or
75 μs.
The seek function will search up or down the selected
frequency band for a valid channel. A valid channel is
qualified according to a series of programmable signal
indicators and thresholds. The seek function can be
made to stop at the band edge and provide an interrupt,
or wrap the band and continue seeking until arriving at
the original departure frequency. The device sets
interrupts with found valid stations or, if the seek results
in zero found valid stations, the device indicates failure
and again sets an interrupt.
4.13. Analog Audio and FM MPX
High-fidelity digital-to-analog converters (DACs) drive
analog audio signals or the FM MPX signal onto the
LOUT/MPXOUT and ROUT pins. At powerup time the
user can configure the analog outputs for either audio or
MPX output. In applications where MPX and audio
outputs are required simultaneously, the analog MPX
signal can be driven onto the MPXOUT pin and the
audio signals can be sourced from the digital audio
interface.
The audio output may be muted. Volume is adjusted
digitally. It is necessary that the volume be maintained
at maximum levels to ensure the highest dynamic range
audio outputs to the external audio processing stage in
a car radio.
4.14. Soft Mute
The soft mute feature is available to attenuate the audio
outputs and minimize audible noise in compromised
signal conditions. The Si4770/77-A20 triggers soft mute
by monitoring signal metrics such as on-channel RSSI
or SNR. The thresholds for activating soft mute are
programmable, as are soft mute attenuation levels and
attack and decay rates. The Si4770/77-A20 provides
the soft mute feature in FM and AM bands.
4.15. AM/FM Dynamic Bandwidth Control
The AM/FM IF channel bandwidth is dynamically
optimized according to on-channel RSSI, and with the
aid of the adjacent and alternate channel RSSI metric.
The Si4770/77-A20 seek functionality is performed
completely on-chip or can be brought out to a
companion processor. The Si4770/77-A20 can provide
base values for signal quality variables to a companion
processor for qualification or can further process the
base values to qualify valid or invalid stations.
The Si4770/77-A20 uses RSSI, SNR, and frequency
offset to qualify stations. These variables have
programmable thresholds to tailor the seek function to
the subjective tastes of customers.
RSSI is employed first to screen all possible candidate
stations. SNR and frequency offset are subsequently
used in screening the RSSI qualified stations. The more
thresholds the system engages, the higher the
confidence that any found stations will indeed be valid
broadcast stations; however, the more challenging
levels the thresholds are set to, the longer the overall
seek time as more stations and more qualifiers will be
assessed.
It is recommended that RSSI be set to a midlevel
threshold in conjunction with an SNR threshold set to a
level delivering acceptable audio performance. This
trade-off will eliminate very low RSSI stations whilst
keeping the seek time to acceptable levels. Generally,
the time to auto-scan and store valid channels for an
entire AM or FM band with all thresholds engaged is
very short depending on the band content.
Seek is initiated using the AM and FM seek commands.
The RSSI and SNR threshold settings are adjustable
using properties.
Rev. 0.9
41
Si4770/77-A20
4.17. AM Hi-Cut Control
4.19. FM Hi-Blend
AM hi-cut control is employed on AM audio outputs with
degradation of signal quality. Signal metrics such as
SNR or on-channel RSSI activate the hi-cut filter.
Programmable minimum and maximum thresholds are
available for all metrics. Attack and release rates for hicut are programmable for all metrics.
FM hi-blend control applies a low-pass filter on the (L-R)
audio upon degradation of received signal quality.
Signal metrics, such as USN, on-channel RSSI, and
multipath interference, activate the hi-blend filter.
Programmable minimum and maximum thresholds are
available for all metrics. Attack and release rates for are
also programmable for all metrics. The level of hi-blend
applied can be monitored with the received signal
quality command. Further information is provided in the
Programming Guide.
The level of hi-cut applied can be monitored with the
received signal quality command. Hi-cut can be
disabled by setting the hi-cut filter setting to the default
audio bandwidth for AM. Further information is provided
in the Programming Guide.
4.18. FM Hi-Cut Control
FM hi-cut control applies a low-pass filter on the (L+R)
audio upon degradation of received signal quality.
Signal metrics, such as USN, on-channel RSSI, and
multipath interference, activate the hi-cut filter.
Programmable minimum and maximum thresholds are
available for all metrics. Attack and release rates are
also programmable for all metrics. The level of hi-cut
applied can be monitored with the received signal
quality command. Further information is provided in the
Programming Guide.
42
4.20. AM Lo-Cut
AM lo-cut is employed on audio outputs for rejection of
power-supply 50/60 Hz interference. AM lo-cut is a high
pass filter. Lo-cut is enabled by default and can be
disabled by programming the filter to being switched off.
Rev. 0.9
Si4770/77-A20
5. RDS/RBDS Advanced Processor
6. Programming Section
The Si4770/77-A20 implements an advanced, patented,
high-performance RDS processor for demodulation,
symbol decoding, block synchronization, error
detection, and error correction. The RDS decoder
applies advanced decoding and statistical decision
To ease development time and offer maximum
customization, the Si4770/77-A20 provides a simple
and powerful software command protocol in addition to
the 2-wire I2C serial interface to communicate with the
host processor.The device is programmed using
commands, arguments, properties, and responses. To
perform an action, the user writes a command byte and
associated arguments, causing the chip to execute the
given command. Commands control actions such as
powerup, powerdown, or tune to a station. Arguments
are specific to a given command and are used to modify
the command. Properties are a special command +
argument used to modify the default chip operation and
are generally configured immediately after powerup.
Examples of properties are de-emphasis level, RSSI
seek threshold, and soft mute attenuation threshold.
Responses provide information and are echoed after a
command + argument is issued and processed. All
commands provide a one-byte status update indicating
interrupt and clear-to-send status information.
techniques
to
provide
high-performance
synchronization at very noisy signal levels, and
excellent sensitivity at industry-standard block error rate
(BLER) levels (5%).
The
Si4770/77-A20’s
strong
synchronization
performance in very noisy/low SNR environments
minimizes the number of instances of lost
synchronization. Other less robust tuners must attempt
to resynchronize in low SNR environments, resulting in
lost data and lengthy delays in reestablishing data
reception.
The
Si4770/77-A20
maintains
synchronization to the RDS transmission, despite high
BLER. This results in fewer dropped connections,
minimal resynchronization time, and greater data
reliability in low SNR environments.
The
Si4770/77-A20
reports
RDS
decoder
synchronization status and detailed bit errors for each
RDS block. The range of reportable bit errors detected
and corrected are 0, 1-2, 3-5, and “not correctable.”
More than five errors indicate that the corresponding
block information word is non-correctable.
The Si4770/77-A20 also provides highly configurable
interrupts based on RDS-driven events and conditions.
The default settings provide an interrupt when RDS is
synchronized and when RDS group data has been
received. The configurable interrupts can be set to
provide frequent interrupts down to a single received
block with BLER. The configurable interrupts also can
be set to provide very infrequent interrupts, buffering up
to 25 complete RDS groups (100 blocks) with BLER
information by block in the on-chip FIFO. The Si4770/
77-A20 also provides configurable interrupts on
changes or receipt of the key RDS blocks A and B. This
flexibility allows adopters to either conduct extensive
RDS data processing on the host or reserve the host
processor in power-saving modes with minimal RDS
interrupts, allowing the Si4770/77-A20 to perform RDS
processing on-chip.
Rev. 0.9
43
Si4770/77-A20
7. I2C Control Bus
A serial port slave interface is provided, which allows an external controller to send commands and receive
responses from the Si4770/77-A20.
7.1. I2C Device Address Selection
Two device I2C addresses are available, allowing up to four Si4770/77-A20 receivers to share the same I2C bus.
The 7-bit device address consists of a fixed part (5 MSBs), followed by a programmable 2-bit part. The LSB of the
device address signals whether a read or write I2C operation occurs. The voltage on the A0 and A1 pins are used
to set the programmable 2-bit part of the device address. The A0 and A1 pins are tied to ground and are left to float
for address selection. The various I2C device addresses can be selected as summarized in Table 18.
7.2. I2C Standard Operation
The I2C bus interface is provided for configuration and monitoring of all internal registers. The Si4770/77-A20
supports a 7-bit device addressing procedure and is capable of operating at clock rates up to 400 kHz. Individual
data transfers to and from the device are eight bits. The I2C bus consists of two wires: a serial clock line (SCL) and
a serial data line (SDA). The device always operates as a bus slave. In order to be active, the I2C block requires
that VIO1 and VD supplies be turned on.
A transaction begins with the START condition, which occurs when SDA falls while SCL is high. Next, the user
drives an 8-bit control byte serially on SDA, which is captured by the device on rising edges of SCL. The control
byte consists of a 7-bit device address followed by a read/write bit (read = 1, write = 0). The Si4770/77-A20
acknowledges the control word by driving SDA low on the next falling edge of SCL.
Read and write operations are performed in accordance with the I2C bus specification. For write operations, the
host sends an 8-bit data byte on SDA, which is captured by the device on rising edges of SCL. The Si4770/77-A20
acknowledges each data byte by driving SDA low for one cycle, after the next falling edge of SCL. The host may
write any number of data bytes in a single two-wire transaction. The first byte is a command, and the next bytes are
arguments.
For read operations, after the Si4770/77-A20 has acknowledged the control byte, it drives an 8-bit data byte on
SDA, changing the state of SDA after the falling edge of SCL. The host acknowledges each data byte by driving
SDA low for one cycle, after the next falling edge of SCL. If a data byte is not acknowledged, the transaction ends.
The host may read any number of data bytes in a single two-wire transaction. These bytes contain the response
data from the Si4770/77-A20. A 2-wire transaction ends with the STOP condition, which occurs when SDA rises
while SCL is high.
Table 18. I2C Device Address Selection
Device Address [6…2] Device Address [1:0]
44
A1 Voltage
(Pin Connection)
A0 Voltage
(Pin Connection)
11000
11
Floating
Floating
11000
10
Floating
GND
11000
01
GND
Floating
11000
00
GND
GND
Rev. 0.9
Si4770/77-A20
Write Operation
S
Device Addr
W A
Command
A
ARG 1
A
ARG 2
A
...
...
A P
R A
Status
A
Response 1
A
Response 2
A
...
...
A P
Read Operation
S
Device Addr
Master
Slave
A= Acknowledge
R = Read
W = Write
S = Start condition
P = Stop condition
Figure 26. I2C Command/Response Protocol
Rev. 0.9
45
Si4770/77-A20
8. Reset, Powerup, and Powerdown
Setting the RSTB pin low will disable analog and digital circuitry, reset the registers to their default settings, and
disable the bus. Setting the RSTB pin high will bring the device out of reset.
The powerup mode powers up the device and provides mode selection. Mode selections include the following:
AM, FM reception (Si4770/77-A20 only).
Crystal oscillator or reference clock input
A powerdown mode is available to reduce power consumption when the part is idle. Putting the device in
powerdown mode will disable analog and digital circuitry while keeping the bus active.


VIO1
VIO2
VD
VA
100 µsec min
RSTB
100 µsec min
SCL
SDA
POWER_UP Command
Figure 27. Startup Timing
46
Rev. 0.9
Si4770/77-A20
9. Pin Descriptions: Si4770/77-A20
VA
33
32
31
36
ROUT
37
LOUT/
MPXOUT
DACREF
38
34
GPIO2
35
GPIO1
39
XTAL1
FMAGC2
40
RCLK/
XTAL2
FMAGC1
NC
1
30
NC
FMXIP
2
29
DCLK
FMXIN
3
28
DFS
RFGND
4
27
DOUT
RFREG
5
26
NC/QOUT
FMO
6
25
NC/IOUT
FMI
7
24
NC/IQFS
NC
8
23
NC/IQCLK
NC
9
22
VIO2
AMI
10
21
DBYP
GND PAD
13
14
15
16
17
18
19
A1
NC
NC
RSTB
SDA
SCL
INTB
VIO1
VD
12
A0
20
11
Figure 28. Si4770/77 Pin Descriptions
Table 19. Pin Descriptions for Si4770/77
Pin Number
Name
I/O
Description
1
NC
I
No connect: Leave floating
2
FMXIP
I
Balanced input to FM mixer (positive)
3
FMXIN
I
Balanced input to FM mixer (negative)
4
RFGND
5
RFREG
O
FM LNA regulator
6
FMO
O
FM LNA output
7
FMI
I
FM LNA input
8
NC
No connect: Leave floating
9
NC
No connect: Leave floating
10
AMI
I
AM single-ended input
11
A0
I
I2C Address 0
12
A1
I
I2C Address 1
13
NC
RF Ground
No connect: Leave floating
Rev. 0.9
47
Si4770/77-A20
Table 19. Pin Descriptions for Si4770/77 (Continued)
Pin Number
Name
14
NC
15
RSTB
16
SDA
17
SCL
I
I2C clock
18
INTB
O
Interrupt, Active Low
19
VIO1
S
Host I/O Supply Voltage (all pads except digital audio and I/Q)
20
VD
S
Digital Voltage Supply
21
DBYP
I
Digital bypass to Ground
22
VIO2
S
Digital audio and I/Q interface supply voltage
23
NC/IQCLK
O
No Connect: Leave floating (Si4770); ZIF I/Q bit clock output (Si4777)
24
NC/IQFS
O
No Connect: Leave floating (Si4770); ZIF I/Q frame sync output
(Si4777)
25
NC/IOUT
O
No Connect: Leave floating (Si4770); ZIF I data output (Si4777)
26
NC/QOUT
O
No Connect: Leave floating (Si4770); ZIF Q data output (Si4777)
27
DOUT
O
Digital audio data output
28
DFS
I
Digital audio frame sync input
29
DCLK
I
Digital audio bit clock input
30
NC
31
VA
S
Analog Voltage Supply
32
LOUT/ MPXOUT
O
Left audio line out / FM MPX output
33
ROUT
O
Right audio line out
34
XTAL2/RCLK
I
Crystal oscillator input/Reference clock input
35
XTAL1
O
Crystal oscillator output
36
DACREF
I
Voltage Reference for analog outputs
37
GPIO2
I/O General-purpose input/output
38
GPIO1
I/O General-purpose input/output
39
FMAGC2
I
FM automatic gain control 2
40
FMAGC1
I
FM automatic gain control 1
PDL
GND PAD
I
Ground. Reference ground
48
I/O
Description
No connect: Leave floating
I
Global Chip Reset
I/O I2C Data input/output
No Connect: Leave floating
Rev. 0.9
Si4770/77-A20
10. Ordering Guide
Part Number,*
Description
Package
Type
Operating
Temperature
Si4770-A20-GM
AM/FM RDS Broadcast Radio Receiver
6 x 6 40-pin QFN
Pb-Free
–40 to 85 °C
Si4777-A20-GM
AM/FM RDS Broadcast Radio Receiver and HD
Radio Tuner
6 x 6 40-pin QFN
Pb-Free
–40 to 85 °C
*Note: Add an “(R)” at the end of the device part number to denote tape and reel option.
Rev. 0.9
49
Si4770/77-A20
11. Package Outline
Figure 29. 40-Pin Quad Flat No-Lead (QFN)
Table 20. Package Dimensions
Dimensions
Min
Nom
Max
A
0.80
0.85
0.90
A1
0.00
0.02
0.05
b
0.18
0.25
0.30
D
D2
6.00 BSC.
3.95
4.10
e
0.50 BSC.
E
6.00 BSC.
4.25
E2
3.95
4.10
4.25
L
0.30
0.40
0.50
aaa
0.10
bbb
0.10
ccc
0.08
ddd
0.10
eee
0.05
Notes:
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
3. This drawing conforms to JEDEC outline MO-220, Variation VJJD-2.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020C specification for Small Body Components.
50
Rev. 0.9
Si4770/77-A20
12. PCB Land Pattern
Figure 30. PCB Land Pattern
Rev. 0.9
51
Si4770/77-A20
Table 21. PCB Land Pattern Dimensions
Dimensions
Min
Max
e
0.50 BSC.
E
5.42 REF.
D
5.42 REF.
E2
4.00
4.20
D2
4.00
4.20
GE
4.53
—
GD
4.53
—
X
—
0.28
Y
0.89 REF.
ZE
—
6.31
ZD
—
6.31
Notes:
General
1.
2.
3.
4.
All dimensions shown are in millimeters (mm) unless otherwise noted.
Dimensioning and Tolerancing is per the ANSI Y14.5M-1994 specification.
This Land Pattern Design is based on IPC-SM-782 guidelines.
All dimensions shown are at Maximum Material Condition (MMC). Least
Material Condition (LMC) is calculated based on a Fabrication Allowance of
0.05 mm.
Solder Mask Design
5. All metal pads are to be non-solder mask defined (NSMD). Clearance between
the solder mask and the metal pad is to be 60 µm minimum, all the way around
the pad.
Stencil Design
6. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls
should be used to assure good solder paste release.
7. The stencil thickness should be 0.125 mm (5 mils).
8. The ratio of stencil aperture to land pad size should be 1:1 for the perimeter
pads.
9. A 4 x4 array of 0.80 mm square openings on 1.05 mm pitch should be used
for the center ground pad.
Card Assembly
10. A No-Clean, Type-3 solder paste is recommended.
11. The recommended card reflow profile is per the JEDEC/IPC J-STD-020
specification for Small Body Components.
52
Rev. 0.9
Si4770/77-A20
13. Top Marking
13.1. Si4770/77-A20 Top Marking
13.2. Top Marking Explanation
Mark Method:
Laser
Pin 1 Mark:
Circle = 0.90 mm diameter
(Bottom-Left-Justified)
Font Size:
0.70 mm Right-Justified
Line 1 Mark Format:
Device Number
4770 = Si4770
4777 = Si4777
A = Part Revision A
20 = Firmware Revision 2.0
Line 2 Mark Format:
TTTTTT = Mfg Code
Manufacturing Code from the Assembly Purchase
Order Form.
Line 3 Mark Format:
YY = Year
WW = Work Week
Assigned by the Assembly House. Corresponds to the
year and work week of the assembly date.
Rev. 0.9
53
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