PLL Frequency Synthesizer for use in Tuners in Radio/Cassette Players

Ordering number : ENA0788A
LC72131K
LC72131KMA
CMOS IC
PLL Frequency Synthesizer
Overview
The LC72131K and LC72131KMA are PLL frequency synthesizers for use in tuners in radio/cassette players.
They allow high-performance AM/FM tuners to be implemented easily.
Features
• High speed programmable dividers
• FMIN: 10 to 160MHz …………………….. pulse swallower (built-in divide-by-two prescaler)
• AMIN: 2 to 40MHz ………………………. pulse swallower
0.5 to 10MHz …………………….. direct division
• IF counter
• IFIN: 0.4 to 12MHz ………………………. AM/FM IF counter
• Reference frequencies
• Twelve selectable frequencies (4.5 or 7.2MHz crystal)
• 100, 50, 25, 15, 12.5, 6.25, 3.125, 10, 9, 5, 3, 1kHz
• Phase comparator
• Dead zone control
• Unlock detection circuit
• Deadlock clear circuit
• Built-in MOS transistor for forming an active low-pass filter
• I/O ports
• Dedicated output ports: 4 • Input or output ports: 2
• Support clock time base output
• Serial data I/O
• Support CCB format communication with the system controller.
Continued on next page.
•
CCB is ON Semiconductor® ’s original format. All addresses are managed
by ON Semiconductor® for this format.
•
CCB is a registered trademark of Semiconductor Components Industries, LLC.
Semiconductor Components Industries, LLC, 2013
June, 2013
O3112HK 20120919-S00009/51407HKIM 20070328-S00008,S00009 No.A0788-1/22
LC72131K, LC72131KMA
Continued from preceding page.
• Operating ranges
• Supply voltage ........................4.5 to 5.5V
• Packages
• DIP22S(300mil) / MFP20J(300mil)
• Operating temperature ............ -40 to +85°C
Specifications
Absolute Maximum Ratings at Ta = 25°C, VSS = 0V
Parameter
Symbol
Pins
Conditions
Ratings
Unit
Supply voltage
VDD max
VDD
-0.3 to +7.0
Maximum input voltage
VIN1 max
CE, CL, DI, AIN
-0.3 to +7.0
V
VIN2 max
XIN, FMIN, AMIN, IFIN
-0.3 to VDD+0.3
V
VIN3 max
IO1, IO2
-0.3 to +15
V
VO1 max
DO
-0.3 to +7.0
V
VO2 max
XOUT, PD
-0.3 to VDD+0.3
V
-0.3 to +15
V
Maximum output voltage
Maximum output current
Allowable power dissipation
V
VO3 max
BO1 to BO4, IO1, IO2, AOUT
IO1 max
BO1
0 to 3.0
IO2 max
DO, AOUT
0 to 6.0
mA
IO3 max
BO2 to BO4, IO1, IO2
0 to 10
mA
Pd max
mA
Ta≤85°C [LC72131K]
350
mW
Ta≤85°C [LC72131KMA]
180
mW
Operating temperature
Topr
-40 to +85
°C
Storage temperature
Tstg
-55 to +125
°C
Note 1: Power pins VDD and VSS: Insert a capacitor with a capacitance of 2,000pF or higher between these pins when
using the IC.
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating
Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability.
No.A0788-2/22
LC72131K, LC72131KMA
Allowable Operating Ranges at Ta = -40°C to +85°C, VSS = 0V
Parameter
Symbol
Pins
Conditions
Ratings
min
typ
max
unit
Supply voltage
VDD
VDD
4.5
5.5
Input high-level voltage
VIH1
CE, CL, DI
0.7VDD
6.5
V
VIH2
IO1, IO2
0.7VDD
13
V
V
Input low-level voltage
VIL
CE, CL, DI, IO1, IO2
0
0.3VDD
V
Output voltage
VO1
DO
0
6.5
V
VO2
BO1 to BO4, IO1, IO2, AOUT
0
13
V
fIN1
XIN
VIN1
1.0
8.0
MHz
fIN2
FMIN
VIN2
10
160
MHz
fIN3
AMIN
VIN3
2.0
40
MHz
fIN4
AMIN
VIN4
0.5
10
MHz
fIN5
IFIN
VIN5
0.4
12
MHz
Supported crystals
X'tal
XIN, XOUT
Note 1
4.0
8.0
Input amplitude
VIN1
XIN
fIN1
400
1500
mVrms
VIN2-1
FMIN
f=10 to 130MHz
40
1500
mVrms
VIN2-2
FMIN
f=130 to 160MHz
70
1500
mVrms
VIN3
AMIN
fIN3
40
1500
mVrms
VIN4
AMIN
fIN4
40
1500
mVrms
VIN5
IFIN
fIN5 (IFS=1)
40
1500
mVrms
VIN6
IFIN
fIN5 (IFS=0)
70
1500
mVrms
Data setup time
tSU
DI, CL
Note 2
0.75
μs
Data hold time
tHD
DI, CL
Note 2
0.75
μs
Clock low-level time
tCL
CL
Note 2
0.75
μs
Clock high-level time
tCH
CL
Note 2
0.75
μs
CE wait time
tEL
CE, CL
Note 2
0.75
μs
CE setup time
tES
CE, CL
Note 2
0.75
μs
CE hold time
tEH
CE, CL
Note 2
0.75
Data latch change time
tLC
Data output time
tDC
DO, CL
Differs depending
tDH
DO, CE
on the value of the
Input frequency
High-level clock pulse width tφH
CL [Figure 1][Figure 2] 160 ns
Low-level clock pulse width
Note 2
pull-up resistor.
MHz
μs
0.75
μs
0.35
μs
Note 2
Note 1: Recommended crystal oscillator CI values:
CI≤120Ω (For a 4.5MHz crystal)
CI≤70Ω (For a 7.2MHz crystal)
The characteristics of the oscillation circuit depends on the printed circuit board, circuit constants, and other
factors. Therefore we recommend consulting with the anufacturer of the crystal for evaluation and reliability.
Note 2: Refer to "Serial Data Timing".
No.A0788-3/22
LC72131K, LC72131KMA
Electrical Characteristics in the Allowable Operating Ranges
Parameter
Built-in feedback resistance
Symbol
Pins
Conditions
Ratings
min
typ
max
unit
Rf1
XIN
1.0
MΩ
Rf2
FMIN
500
kΩ
Rf3
AMIN
500
kΩ
Rf4
IFIN
250
kΩ
Rpd1
FMIN
200
kΩ
Rpd2
AMIN
200
kΩ
Hysteresis
VHYS
CE, CL, DI, IO1, IO2
Output high-level voltage
VOH
PD
IO=1mA
Output low-level voltage
VOL1
PD
IO=1mA
1.0
V
VOL2
BO1
V
Built-in pull-down resistor
VOL3
VOL4
VOL5
Input high-level current
Input low-level current
DO
BO2 to BO4, IO1, IO2
0.1VDD
V
VDD-0.1
V
IO=0.5mA
0.5
IO=1mA
1.0
V
IO=1mA
0.2
V
IO=5mA
1.0
V
IO=1mA
0.2
V
IO=5mA
1.0
V
IO=8mA
1.6
V
AOUT
IO=1mA AIN=1.3V
0.5
V
5.0
μA
IIH1
CE, CL, DI
VI=6.5V
IIH2
IO1, IO2
VI=13V
5.0
μA
IIH3
XIN
VI=VDD
2.0
11
μA
IIH4
FMIN, AMIN
VI=VDD
4.0
22
μA
IIH5
IFIN
VI=VDD
8.0
44
μA
IIH6
AIN
VI=6.5V
200
nA
IIL1
CE, CL, DI
VI=0V
5.0
μA
IIL2
IO1, IO2
VI=0V
5.0
μA
IIL3
XIN
VI=0V
2.0
11
μA
IIL4
FMIN, AMIN
VI=0V
4.0
22
μA
IIL5
IFIN
VI=0V
8.0
44
μA
IIL6
AIN
VI=0V
200
nA
Output off leakage current
IOFF1
BO1 to BO4, AOUT, IO1, IO2
VO=13V
5.0
μA
IOFF2
DO
VO=6.5V
5.0
μA
High-level three-state off leakage
IOFFH
PD
VO=VDD
0.01
200
nA
IOFFL
PD
VO=0V
0.01
200
nA
current
Low-level three-state off leakage
current
Input capacitance
CIN
FMIN
Current drain
IDD1
VDD
6
fIN2=130MHz
IDD2
VDD
pF
X'tal=7.2MHz
5
10
mA
VIN2=40mVrms
PLL block stopped
(PLL INHIBIT)
X'tal oscillator
0.5
mA
operating
(X'tal=7.2MHz)
IDD3
VDD
PLL block stopped
X'tal oscillator
10
μA
operating
No.A0788-4/22
LC72131K, LC72131KMA
≈
Serial Data Timing
VIH
tCL
VIH
VIL
CL
VIH
VIL
tHD
tEL
≈ ≈ ≈ ≈ ≈ ≈
VIH
tSU
VIH
VIL
DI
VIL
VIL
DO
Internal
data latch
VIH
VIL
≈ ≈ ≈ ≈ ≈ ≈ ≈
tCH
≈ ≈
CE
tES
tDC
tDC
tEH
tDH
tLC
Old
New
≈
When stopped with CL low
VIH
VIH
VIL
VIH
VIH
VIH
DI
VIL
tSU
tHD
DO
Internal
data latch
VIH
VIL
≈ ≈ ≈ ≈ ≈ ≈ ≈
CL
VIL
≈
tCL
tEL
VIL
tES
tEH
≈ ≈ ≈ ≈ ≈ ≈
tCH
≈
CE
tDC
tDH
tLC
Old
New
When stopped with CL high
Package Dimensions
Package Dimensions
unit : mm (typ)
3059A [LC72131K]
unit : mm (typ)
3445 [LC72131KMA]
12.7
21.0
20
22
7.8
1 2
1.27
0.4
0.15
(0.8)
1.78
0.48
SANYO : DIP22S(300mil)
0.05
1.8
(3.25)
(0.635)
0.51min
3.3 3.9 max
0.5
11
0.95
0.25
1
5.4
6.4
7.62
12
SANYO : MFP20J(300mil)
No.A0788-5/22
LC72131K, LC72131KMA
XOUT
VSS
AOUT
AIN
PD
VDD
FMIN
AMIN
NC
IO2
IFIN
Pin Assignments
22
21
20
19
18
17
16
15
14
13
12
2
3
4
5
6
7
8
9
10
NC
CE
DI
CL
DO
BO1
BO2
BO3
BO4
11
IO1
1
XIN
LC72131K
XOUT
VSS
AOUT
AIN
PD
VDD
FMIN
AMIN
IO2
IFIN
Top view
20
19
18
17
16
15
14
13
12
11
1
2
3
4
5
6
7
8
9
10
XIN
CE
DI
CL
DO
BO1
BO2
BO3
BO4
IO1
LC72131KMA
Top view
Block Diagram
REFERENCE
DIVIDER
XIN
PHASE DETECTOR
CHARGE PUMP
PD
XOUT
FMIN
1/2
SWALLOW COUNTER
1/16,1/17 4bits
UNLOCK
DETECTOR
AIN
AOUT
12bits PROGRAMMABLE
DIVIDER
AMIN
CE
DI
CL
CCB
I/F
DATA SHIFT REGISTER
LATCH
UNIVERSAL
COUNTER
IFIN
DO
VDD
VSS
POWER
ON
RESET
BO1 BO2 BO3 BO4
IO1 IO2
No.A0788-6/22
LC72131K, LC72131KMA
Pin Functions
Symbol
Pin No.
LC72131K
LC72131KMA
XIN
1
1
XOUT
22
20
FMIN
16
14
Type
X'tal OSC
Functions
Circuit configuration
Crystal resonator connection
(4.5MHz/7.2MHz)
Local
FMIN is selected when the serial data input DVS bit is set to 1.
oscillator
The input frequency range is from 10 to 160MHz.
signal input
The input signal passes through the internal divide-by-two
prescaler and is input to the swallow counter.
The divisor can be in the range 272 to 65535. However,
since the signal has passed through the divide-by-two
prescaler, the actual divisor is twice the set value.
AMIN
15
13
Local
AMIN is selected when the serial data input DVS bit is set to 0.
oscillator
When the serial data input SNS bit is set to 1:
signal input
• The input frequency range is 2 to 40MHz.
• The signal is directly input to the swallow counter.
• The divisor can be in the range 272 to 65535, and the divisor
used will be the value set.
When the serial data input SNS bit is set to 0:
• The input frequency range is 0.5 to 10MHz.
• The signal is directly input to a 12-bit programmable divider.
• The divisor can be in the range 4 to 4095, and the divisor
used will be the value set.
CE
3
2
Chip enable
Set this pin high when inputting (DI) or outputting (DO) serial
S
data.
DI
4
3
Input data
Inputs serial data transferred from the controller to the
S
LC72131K/KMA.
CL
5
4
Clock
DO
6
5
Output data
S
Used as the synchronization clock when inputting (DI) or
outputting (DO) serial data.
Outputs serial data transferred from the LC72131K/KMA to the
controller.
The content of the output data is determined by the serial data
DOC0 to DOC2.
VDD
17
15
Power supply
The LC72131K/KMA power supply pin (VDD=4.5 to 5.5V)
The power on reset circuit operates when power is first applied.
VSS
21
19
Ground
The LC72131K/KMA ground
BO1
7
6
Output port
Dedicated output pins
BO2
8
7
The output states are determined by BO1 to BO4 bits in
BO3
9
8
the serial data.
BO4
10
9
-
Data: 0=open, 1=low
A time base signal (8Hz) can be output from the BO1 pin.
(When the serial data TBC bit is set to 1.)
Care is required when using the BO1 pin, since it has a higher on
impedance that the other output ports (pins BO2 to BO4).
IO1
11
10
IO2
13
12
I/O port
I/O dual-use pins
The direction (input or output) is determined by bits IOC1 and
IOC2 in the serial data.
Data: 0=input port, 1=output port
When specified for use as input ports:
S
The state of the input pin is transmitted to the controller over
the DO pin.
Input state: low=0 data value
high=1 data value
When specified for use as output ports:
The output states are determined by the IO1 and IO2 bits in
the serial data.
Data: 0=open, 1=low
These pins function as input pins following a power on reset.
Continued on next page.
No.A0788-7/22
LC72131K, LC72131KMA
Continued from preceding page.
Pin No.
Symbol
PD
LC72131K
LC72131KMA
18
16
Type
Functions
Charge pump
Circuit configuration
PLL charge pump output
output
When the frequency generated by dividing the local oscillator
frequency by N is higher than the reference frequency, a high
level is output from the PD pin.
Similarly, when that frequency is lower, a low level is output.
The PD pin goes to the high impedance state when the
frequencies match.
AIN
19
17
LPF amplifier
The n-channel MOS transistor used for the PLL active
AOUT
20
18
transistors
low-pass filter.
IFIN
12
11
IF counter
Accepts an input in the frequency range 0.4 to 12MHz.
The input signal is directly transmitted to the IF counter.
The result is output starting the MSB of the IF counter using the
DO pin.
Four measurement periods are supported: 4, 8, 32, and 64ms.
DI Control Data (Serial Data Input) Structure
[1] IN1 mode
address
DI
0
0
0
1
0
1
0
0
R3
R2
(2) R-CTR
R1
R0
XS
(3) IF-CTR
CTE
DVS
SNS
P15
P14
P13
P12
P11
P10
P9
P7
BO4
P8
P6
0
(1) P-CTR
P5
0
BO3
P4
1
BO2
P3
P2
P1
P0
First Data IN1
[2] IN2 mode
address
1
0
0
1
0
TEST2
TEST1
IFS
(11) IFS
(12) TEST
DLC
(10) PD-C
TEST0
TBC
GT1
(9) TIME
(3) IF-CTR
GT0
DZ1
UL1
DZ0
(8) DZ-C
(7) UNLOCK
UL0
DOC2
DOC1
(6) DO-C
DOC0
DNC
(13) Don’t care
(5) O-PORT
BO1
IO2
IO1
IOC2
IOC1
First Data IN2
(4) IO-C
DI
No.A0788-8/22
LC72131K, LC72131KMA
Control Data Functions
No.
(1)
Control block/data
Functions
Related data
Programmable
Data that sets the divisor of the programmable divider.
divider data
A binary value in which P15 is the MSB. The LSB changes depending on
P0 to P15
DVS and SNS. (*: don’t care)
DVS
SNS
LSB
Divisor setting (N)
Actual divisor
1
0
0
*
1
0
P0
P0
P4
272 to 65535
272 to 65535
4 to 4095
Twice the value of the setting
The value of the setting
The value of the setting
Note: P0 to P3 are ignored when P4 is the LSB.
DVS, SNS
Selects the signal input pin (AMIN or FMIN) for the programmable divider, switches
the input frequency range. (*: don’t care)
DVS
SNS
Input pin
1
0
0
*
1
0
FMIN
AMIN
AMIN
Input frequency range
10 to 160MHz
2 to 40MHz
0.5 to 10MHz
Note: See the “Programmable Divider Structure” item for more information.
(2)
Reference divider
data
R0 to R3
Reference frequency (fref) selection data.
R3
R2
R1
R0
Reference frequency
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
100kHz
50
25
25
12.5
6.25
3.125
3.125
1
1
1
1
0
0
0
0
0
0
1
1
0
1
0
1
10
9
5
1
1
1
1
1
0
0
0
1
3
15
1
1
1
0
1
1
1
1
* PLL INHIBIT + X'tal OSC STOP
* PLL INHIBIT
Note *: PLL INHIBIT
The programmable divider block and the IF counter block are stopped, the FMIN, AMIN,
and IFIN pins are set to the pull-down state (ground), and the charge pump goes to the
high impedance state.
XS
Crystal resonator selection
XS=0: 4.5MHz
XS=1: 7.2MHz
The 7.2MHz frequency is selected after the power-on reset.
(3)
IF counter control
IF counter measurement start data
data
CTE=1: Counter start
CTE
GT0, GT1
IFS
=0: Counter reset
Determines the IF counter measurement period.
GT1
GT0
0
0
1
1
0
1
0
1
Measurement time (ms)
4
8
32
64
Wait time (ms)
3 to 4
3 to 4
7 to 8
7 to 8
Note: See the “IF Counter Structure” item for more information.
Continued on next page.
No.A0788-9/22
LC72131K, LC72131KMA
Continued from preceding page.
No.
Control block/data
(4)
I/O port specification
data
Functions
Related data
Specifies the I/O direction for the bidirectional pins IO1 and IO2.
Data: 0=input mode, 1=output mode
IOC1, IOC2
(5)
Output port data
BO1 to BO4
(6)
Data that determines the output from the BO1 to BO4, IO1 and IO2 output ports
IOC2
IO1, IO2
The data=0 (open) state is selected after the power-on reset.
DO pin control data
Data that determines the DO pin output
DOC0
DOC1
DOC2
IOC1
Data: 0=open, 1=low
UL0, UL1
DOC2
DOC1
DOC0
Do pin state
CTE
0
0
0
0
0
0
1
1
0
1
0
1
Open
Low when the unlock state is detected
end-UC *1
Open
IOC1
1
1
1
1
0
0
1
1
0
1
0
1
Open
The IO1 pin state *2
The IO2 pin state *2
IOC2
Open
The open state is selected after the power-on reset.
≈
Note: 1. end-UC: Check for IF counter measurement completion
≈
DO pin
(1) Count start
(2) Count end
(3)CE: High
(1) When end-UC is set and the IF counter is started (i.e., when CTE is changed from
zero to one), the DO pin automatically goes to the open state.
(2) When the IF counter measurement completes, the DO pin goes low to indicate the
measurement completion state.
(3) Depending on serial data I/O (CE: high) the DO pin goes to the open state.
Note: 2. Goes to the open state if the I/O pin is specified to be an output port.
Caution: The state of the DO pin during a data input period (an IN1 or IN2 mode period with CE
high) will be open, regardless of the state of the DO control data (DOC0 to DOC2).
Also, the DO pin during a data output period (an OUT mode period with CE high) will
output the contents of the internal DO serial data in synchronization with the CL pin
signal, regardless of the state of the DO control data (DOC0 to DOC2).
(7)
Unlock detection
Selects the phase error (φE) detection width for checking PLL lock.
DOC0
data
A phase error in excess of the specified detection width is seen as an unlocked state.
DOC1
UL0, UL1
UL1
UL0
0
0
1
1
0
1
0
1
φE detection width
stopped
0
±0.55μs
±1.11
DOC2
Detector output
Open
φE is output directry
φE is extended by 1 to 2ms
↑
Note: In the unlocked state the DO pin goes low and the UL bit in the serial data becomes zero.
Continued on next page.
No.A0788-10/22
LC72131K, LC72131KMA
Continued from preceding page.
No.
Control block/data
(8)
Functions
Phase comparator
Related data
• Controls the phase comparator dead zone.
control data
DZ0, DZ1
DZ1
DZ0
Dead zone mode
0
0
1
1
0
1
0
1
DZA
DZB
DZC
DZD
Dead zone width: DZA<DZB<DZC<DZD
(9)
(10)
Clock time base
Setting TBC to one causes an 8Hz, 40% duty clock time base signal to be output from the BO1
TBC
pin. (BO1 data is invalid in this mode.)
Charge pump control
Forcibly controls the charge pump output.
data
DLC
DLC
Charge pump output
0
1
Normal operation
Forced low
BO1
Note: If deadlock occurs due to the VCO control voltage (Vtune) going to zero and the VCO
oscillator stopping, deadlock can be cleared by forcing the charge pump output to low and
(11)
setting Vtune to VCC. (This is the deadlock clearing circuit.)
This data must be set 1 in normal mode.
IF counter control
data
IFS Though if this value is set to zero, the system enters input sensitivity degradation mode,
IFS
and the sensitivity is reduced to 10 to 30mVrms.
* See the “IF Counter Operation” item for details.
(12)
LSI test data
LSI test data
TEST0 to 2
TEST0
TEST1
These values must all be set to 0.
TEST2
These test data are set to 0 automatically after the power-on reset.
(13)
DNC
Don’t care. This data must be set to 0.
DO Control Data (Serial Data Output) Structure
[3] OUT Mode
0
1
0
1
0
1
0
0
C16
DI
C17
address
C0
C1
C2
C3
C4
C5
C6
C7
C8
C9
C11
C12
C13
C14
C15
C18
C19

I1
C10
(3) IF-CTR
(2) UNLOCK
(1) IN-PORT
I2
DO
UL
Fist Data OUT
: Must be 0.
No.A0788-11/22
LC72131K, LC72131KMA
Control Data Functions
No.
Control block/data
(1)
Functions
Latched from the pin states of the IO1 and IO2 I/O ports.
IOC1
I2, I1
These values follow the pin states regardless of the input or output setting.
High: 1
I1 ← IO1 pin state
IOC2
PLL unlock data
Latched from the state of the unlock detection circuit.
I2 ← IO2 pin state
(2)
Related data
I/O port data
Low: 0
UL0
UL ← 0: Unlocked
UL
UL1
UL ← 1: Locked or detection stopped mode
(3)
IF counter binary
Latched from the value of the IF counter (20-bit binary counter).
CTE
counter
C19 ← MSB of the binary counter
GT0
C19 to C0
C0 ← LSB of the binary counter
GT1
Serial Data I/O Methods
The LC72131K/KMA inputs and outputs data using Our CCB (computer control bus) audio LSI serial bus format. This
LSI adopts an 8-bit address format CCB.
I/O mode
Address
B0
B1
B2
B3
A0
A1
A2
Function
A3
• Control data input mode (serial data input)
[1]
IN1 (82)
0
0
0
1
0
1
0
0
• 24 data bits are input.
• See the “DI Control Data (serial data input) Structure” item for details
on the meaning of the input data.
• Control data input mode (serial data input)
[2]
IN2 (92)
1
0
0
1
0
1
0
0
• 24 data bits are input.
• See the “DI Control Data (serial data input) Structure” item for details
on the meaning of the input data.
• Data output mode (serial data output)
[3]
OUT (A2)
0
1
0
1
0
1
0
0
• The number of bits output is equal to the number of clock cycles.
• See the “DO Control Data (serial data output) Structure” item for details
on the meaning of the output data.
≈
I/O mode determined
≈
CE
(1)
CL
DI
B0
B1
B2
B3
A0
A1
A2
A3
First Data IN1/2
(1)
First Data OUT
DO
(2)
(1) CL: Normal high
(2) CL: Normal low
First Data OUT
≈ ≈ ≈ ≈ ≈ ≈ ≈
(2)
No.A0788-12/22
LC72131K, LC72131KMA
1. Serial Data Input (IN1/IN2) tSU, tHD, tES, tEH≥0.75μs tLC<0.75μs
(1) CL: Normal high
tEL
tES
tEH
CE
CL
tSU
DI
tHD
B0
B1
B2
B3
A0
A1
A2
A3
P0
P1
P2
P3
R0
R1
R2
R3
tLC
Internal data
(2) CL: Normal low
tEL
tES
tEH
CE
CL
tSU
DI
tHD
B0
B1
B2
B3
A0
A1
A2
A3
P0
P1
P2
P3
R0
R1
R2
R3
tLC
Internal data
2. Serial Data Output (OUT) tSU, tHD, tEL, tES, tEH≥0.75μs tDC, tDH<0.35μs
(1) CL: Normal high
tEL
tES
tEH
CE
CL
tSU
DI
tHD
B0
B1
B2
B3
A0
A1
A2
A3
tDC
DO
tDC
I2
I1
tDH
UL
C3
C2
C1
C0
(2) CL: Normal low
tEL
tES
tEH
CE
CL
tSU
DI
tHD
B0
B1
B2
B3
A0
A1
A2
A3
tDC
DO
tDC
I2
I1
tDH
UL
C3
C2
C1
C0
Note: Since the DO pin is an N-channel open-drain pin, the time for the data to change (tDC and tDH) will differ
depending on the value of the pull-up resistor and printed circuit board capacitance.
No.A0788-13/22
LC72131K, LC72131KMA
Programmable Divider Structure
4bits
1/2
FMIN
12bits
(A)
Swallow
Counter
Programmable
Divider
(C)
(B)
AMIN
fvco/N
φE
PD
fref
DVS
fvco=fref×N
SNS
DVS
SNS
Input pin
Set divisor
Actual divisor: N
Input frequency range
(A)
1
*
FMIN
272 to 65535
Twice the set value
10 to 160MHz
(B)
1
1
AMIN
272 to 65535
The set value
2 to 40MHz
(C)
0
0
AMIN
4 to 4095
The set value
0.5 to 10MHz
*: Don't care
Programmable Divider Calculation Examples
(1) FM, 50kHz steps (DVS=1, SNS=*: FMIN selected)
FM RF=90.0MHz (IF=+10.7MHz)
FM VCO=100.7MHz
PLL fref=25kHz (R0 to R1=1, R2 to R3=0)
100.7MHz (FMVCO)÷25kHz (fref) ÷2 (FMIN: divide-by-two prescaler) =2014→07DE (HEX)
0
0
R3
1
0
R2
0
1
R1
0
1
R0
1
XS
*
CTE
0
DVS
P13
0
SNS
0
P15
0
P14
0
P14
1
P12
1
P11
1
0
P10
1
P9
P5
1
P8
0
P7
1
7
P6
1
P4
P1
1
P3
1
D
P2
0
P0
E
0
1
0
1
(2) SW 5kHz steps (DVS=0, SNS=1: AMIN high-speed side selected)
SW RF=21.75MHz (IF=+450kHz)
SW VCO=22.20MHz
PLL fref=5kHz (R0=R2=0, R1=R3=1)
22.2MHz (SW VCO) ÷5kHz (fref) =4440→1158 (HEX)
0
0
0
0
0
P15
SNS
DVS
R3
0
0
0
0
1
R3
1
R2
0
R2
0
R1
1
R1
0
R0
0
R0
DVS
0
XS
SNS
1
CTE
P15
*
P14
P13
*
P13
P12
*
P12
P11
*
P11
0
P10
1
P10
P9
0
P9
P8
0
P8
P7
P5
0
P7
P4
1
P6
P3
0
P6
P2
1
P5
0
P4
1
P3
1
P2
0
1
P1
0
1
P0
0
P1
5
P0
8
(3) MW 10kHz steps (DVS=0, SNS=0: AMIN low-speed side selected)
MW RF=1000kHz (IF=+450kHz)
MW VCO=1450kHz
PLL fref=10kHz (R0 to R2=0, R3=1)
1450kHz (MW VCO) ÷10kHz (fref)=145→091 (HEX)
0
XS
9
CTE
1
No.A0788-14/22
LC72131K, LC72131KMA
IF Counter Structure
The LC72131K/KMA IF counter is a 20-bit binary counter. The result, i.e., the counter’s msb, can be read serially from
the DO pin.
IF counter
(20bits binary counter)
(Fc)
L
S
B
0 to 3
IFIN
(GT)
4/8/32/64ms
M
S
B
4 to 7 8 to 11 12 to 15 16 to 19
DO pin
(C)
CTE
GT1
GT0
C=Fc×GT
Measurement time
GT1
GT0
Measurement time (GT) (ms)
Wait time (twu) (ms)
0
0
4
3 to 4
0
1
8
3 to 4
1
0
32
7 to 8
1
1
64
7 to 8
The IF frequency (Fc) is measured by determining how many pulses were input to an IF counter in a specified
measurement period, GT.
Fc=
C
(C=Fc×GT)
GT
C: Count value (number of pulses)
IF Counter Frequency Calculation Examples
(1) When the measurement period (GT) is 32ms, the count (C) is 53980 hexadecimal (342400 decimal):
IF frequency (Fc) =342400÷32ms=10.7MHz
0
0
0
0
C0
0
C1
C6
0
C2
0
C3
1
C4
1
0
C5
0
C7
0
C8
1
8
C9
1
C10
C14
1
C11
0
C12
0
9
C13
1
C15
C18
0
C16
1
3
C17
0
C19
UL
I1
I2
5
(2) When the measurement period (GT) is 8ms, the count (C) is E10 hexadecimal (3600 decimal):
IF frequency (Fc) =3600÷8ms=450kHz
0
0
0
0
0
0
0
0
1
1
1
0
0
0
0
1
0
0
0
0
C15
C14
C13
C12
C11
C10
C9
C8
C7
C6
C5
C4
C3
C2
C1
C0
0
C16
1
C17
E
C18
0
C19
UL
I1
I2
0
No.A0788-15/22
LC72131K, LC72131KMA
IF Counter Operation
CE
CTE data=1
Measurement
time
GT
Frequncy
Measurement
time
Wait time
IFIN
Count start
Count end (end-UC)
Before starting the IF count, the IF counter must be reset in advance by setting CTE in the serial data to 0.
The IF count is started by changing the CTE bit in the serial data from 0 to 1. The serial data is latched by the
LC72131K/KMA when the CE pin is dropped from high to low. The IF signal must be supplied to the IFIN pin in the
period between the point the CE pin goes low and the end of the wait time at the latest. Next, the value of the IF
counter at the end of the measurement period must be read out during the period that CTE is 1. This is because the IF
counter is reset when CTE is set to 0.
Note: When operating the IF counter, the control microprocessor must first check the state of the IF-IC SD (station
detect) signal and only after determining that the SD signal is present turn on IF buffer output and execute an
IF count operation. Autosearch techniques that use only the IF counter are not recommended, since it is
possible for IF buffer leakage output to cause incorrect stops at points where there is no station.
IFIN minimum input sensitivity standard
IFS
f [MHz]
0.4≤f<0.5
0.5≤f<8
8≤f≤12
1: Normal mode
40mVrms (0.1 to 3mVrms)
40mVrms
40mVrms (1 to 10mVrms)
0: Degradation mode
70mVrms (10 to 15mVrms)
70mVrms
70mVrms (30 to 40mVrms)
Note: Values in parentheses are actual performance values presented as reference data.
Unlock Detection Timing
Unlock Detection Determination Timing
Unlocked state detection is performed in the reference frequency (fref) period (interval). Therefore, in principle,
unlock determination requires a time longer than the period of the reference frequency. However, immediately after
changing the divisor N (frequency) unlock detection must be performed after waiting at least two periods of the
reference frequency.
CE
DATA
LATCH
Old data
New data
VCO/N
Ncounter
Old divisor N
New divisor N’
fref
φERROR
(unlock)
The divisor N is not updated
during the first period.
Note: After changing the divisor, φERROR
is output after two fref periods.
Figure 1 Unlocked State Detection Timing
For example, if fref is 1kHz, i.e., the period is 1ms, after changing the divisor N, the system must wait at least 2ms
before checking for the unlocked state.
No.A0788-16/22
LC72131K, LC72131KMA
÷R
VCO
÷N
fref
VCO/N
UNLOCK
detection circuit
UNLOCK
Phase
comparator
φERROR
L.P.F
Preset
DATA LATCH
Figure 2 Circuit Structure
Data input
Data output (1) Data output (2)
CE
N
Old data
New data
VCO
frequency
φERROR
Unlock (UL)
serial data output
Unlock detection
pin output
Locked
Unlocked
Locked
Figure 3
Unlocked State Data Output Using Serial Data Output
In the LC72131K/KMA, once an unlocked state occurs, the unlocked state serial data (UL) will not be reset until a
data input (or output) operation is performed. At the data output (1) point in Figure 3, although the VCO frequency
has stabilized (locked), since no data output has been performed since the divisor N was changed the unlocked state
data remains in the unlocked state. As a result, even though the frequency has stabilized (locked), the system
remains (from the standpoint of the data) in the unlocked state.
Therefore, the unlocked state data acquired at data output (1), which occurs immediately after the divisor N was
changed, should be treated as a dummy data output and ignored. The second data output (data output (2)) and
following outputs are valid data.
<Locked State Determination Flowchart Example>
Divisor N modification
(data input)
Wait for at least two reference
frequency periods.
Dummy data output
Valid data can be output at
intervals of one reference
frequency period or longer.
Valid data output
locked
*
YES
NO
*: Locking state determination is
more reliable if it is based on
reading valid output data several
times
No.A0788-17/22
LC72131K, LC72131KMA
Directly Outputting Unlocked State Data from the DO Pin (Set by the DO pin control data)
Since the unlocked state (high=locked, low=unlocked) is output directly from the DO pin, the dummy data
processing described in section 3 above is not required. After changing the divisor N, the locking state can be
checked after waiting at least two reference frequency periods.
Clock Time Base Usage Notes
The pull-up resistor used on the clock time base output pin (BO1) should be at least 100kΩ. This is to prevent
degrading the VCO C/N characteristics when a loop filter is formed using the built-in low-pass filter transistor. Since
the clock time base output pin and the low-pass filter have a common ground internal to the IC, it is necessary to
minimize the time base output pin current fluctuations and to suppress their influence on the low-pass filter. Also, to
prevent chattering we recommend using a Schmitt input at the controller (microprocessor) that receives this signal.
VDD
LC72131K/KMA
Rt≥100kΩ
BO1
Microprocessor
S
Time base output
Schmitt input
PD
VCC
AOUT
VCO
Vt
AIN
Loop filter
Other Items
[1] Notes on the Phase Comparator Dead Zone
DZ1
DZ0
Dead zone mode
Charge pump
Dead zone
0
0
DZA
ON/ON
- -0s
0
1
DZB
ON/ON
-0s
1
0
DZC
OFF/OFF
+0s
1
1
DZD
OFF/OFF
++0s
Since correction pulses are output from the charge pump even if the PLL is locked when the charge pump is in the
ON/ON state, the loop can easily become unstable. This point requires special care when designing application
circuits.
The following problems may occur in the ON/ON state.
(1) Side band generation due to reference frequency leakage
(2) Side band generation due to both the correction pulse envelope and low frequency leakage
Schemes in which a dead zone is present (OFF/OFF) have good loop stability, but have the problem that
acquiring a high C/N ratio can be difficult. On the other hand, although it is easy to acquire a high C/N ratio with
schemes in which there is no dead zone, it is difficult to achieve high loop stability. Therefore, it can be effective
to select DZA or DZB, which have no dead zone, in applications which require an FM S/N ratio in excess of 90 to
100dB, or in which an increased AM stereo pilot margin is desired. On the other hand, we recommend selecting
DZC or DZD, which provide a dead zone, for applications which do not require such a high FM signal-to-noise
ratio and in which either AM stereo is not used or an adequate AM stereo pilot margin can be achieved.
No.A0788-18/22
LC72131K, LC72131KMA
Dead Zone
The phase comparator compares fp to a reference frequency (fr) as shown in Figure 1. Although the
characteristics of this circuit (see Figure 2) are such that the output voltage is proportional to the phase difference
ø (line A), a region (the dead zone) in which it is not possible to compare small phase differences occurs in actual
ICs due to internal circuit delays and other factors (line B). A dead zone as small as possible is desirable for
products that must provide a high S/N ratio.
However, since a larger dead zone makes this circuit easier to use, a larger dead zone is appropriate for
popularlypriced products. This is because it is possible for RF signals to leak from the mixer to the VCO and
modulate the VCO in popularly-priced products in the presence of strong RF inputs. When the dead zone is
narrow, the circuit outputs correction pulses and this output can further modulate the VCO and generate beat
frequencies with the RF signal.
V
RF
(A)
MIX
Reference Divider
Programmable Divider
fr
Signal leak
Phase
fp
(B)
LPF
VCO
φ(ns)
Detector
Dead Zone
Figure 2
Figure 1
[2] Notes on the FMIN, AMIN, and IFIN Pins
Coupling capacitors must be placed as close as possible to their respective pin. A capacitance of about 100pF is
desirable. In particular, if a capacitance of 1000pF or over is used for the IF pin, the time to reach the bias level
will increase and incorrect counting may occur due to the relationship with the wait time.
[3] Notes on IF Counting→SD must be used in conjunction with the IF counting time
When using IF counting, always implement IF counting by having the microprocessor determine the presence of
the IF-IC SD (station detect) signal and turn on the IF counter buffer only if the SD signal is present. Schemes in
which auto-searches are performed with only IF counting are not recommended, since they can cause false
detection where there is no signal due to overflow from the IF counter buffer.
[4] DO Pin Usage Techniques
In addition to data output mode times, the DO pin can also be used to check for IF counter count completion and
for unlock detection output. Also, an input pin state can be output unchanged through the DO pin and input to the
controller.
Pin States After the Power ON Reset [LC72131K]
XIN
XOUT
NC
VSS
CE
AOUT
DI
AIN
CL
PD
Open
DO
Open
BO1
FMIN
Open
BO2
AMIN
Open
BO3
NC
Open
BO4
IO2
Input port
IO1
IFIN
LC72131K
VDD
Input port
No.A0788-19/22
LC72131K, LC72131KMA
Pin States After the Power ON Reset [LC72131KMA]
XIN
XOUT
CE
VSS
DI
AOUT
CL
AIN
PD
Open
DO
Open
BO1
Open
BO2
FMIN
Open
BO3
AMIN
Open
BO4
IO2
Input port
IO1
IFIN
LC72131KMA
VDD
Input port
Application System Example [LC72131K]
μ-COM
22 XOUT
NC 2
21 VSS
CE
CE 3
S
20 AOUT
DI
DI 4
S
19 AIN
CL
CL 5
S
18 PD
DO
DO 6
LC72131K
Unlock
tune
end-UC
IFcount
ST-indic
XIN 1
BO1 7
AMVCO
16 FMIN
15 AMIN
BO3 9
14 NC
S
13 IO2
IO1 11
S
FMVCO
17 VDD
BO2 8
BO4 10
VCC
12 IFIN
tune
AM/FM-IF
TUNER-System
IF-Request
FM/AM
MONO/ST
ST-Indicate
No.A0788-20/22
LC72131K, LC72131KMA
Application System Example [LC72131KMA]
XIN 1
μ-COM
CE
CE 2
S
19 VSS
DI
DI 3
S
18 AOUT
CL
CL 4
S
17 AIN
DO
DO 5
LC72131KMA
Unlock
tune
end-UC
IFcount
ST-indic
20 XOUT
BO1 6
15 VDD
AMVCO
14 FMIN
BO3 8
13 AMIN
S
IO1 10
12 IO2
S
FMVCO
16 PD
BO2 7
BO4 9
VCC
11 IFIN
tune
AM/FM-IF
TUNER-System
IF-Request
FM/AM
MONO/ST
ST-Indicate
No.A0788-21/22
LC72131K, LC72131KMA
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application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental
damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual
performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical
experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use
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PS No.A0788-22/22