Datasheet LC72146 Datasheet (SANYO)

CMOS LSI

Ordering number : EN4922C

73096HA (OT)/11095TH (OT) No. 4922-1/21

SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters

TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN

PLL Frequency Synthesizer

for Electronic Tuning

LC72146, 72146M

Overview

The LC72146 is a PLL frequency synthesizer LSI circuit
for electronic tuning in car stereo systems. The LC72146
supports the construction of high-performance, multi­functional electronic tuning systems for the VHF MW,
and LW bands.

Features

• High-speed programmable dividers for
— 10 to 160 MHz on FMIN using pulse swallower
— 0.5 to 40.0 MHz on AMIN using pulse swallower

and direct division

• General-purpose counters
— HCTR for 0.4 to 25.0 MHz frequency measurement
— LCTR for 10 to 500 kHz frequency measurement

and 1.0 Hz to 20 × 103kHz period measurement

• Reference frequencies: Twelve selectable reference
frequencies (4.5 or 7.2 MHz crystal) 1, 3, 5, 9, 10,

3.125, 6.25, 12.5, 25, 30, 50 and 100 kHz

• Phase comparator
— Insensitive band control
— Unlock detection
— Sub-charge pump for high-speed locking
— Deadlock clear circuit

• CCB input/output data interface

• Power-on reset circuit

• Built-in MOS transistor for a low-pass filter

• Inputs/outputs (using five general-purpose input/output
ports)
— Maximum of seven inputs (max)
— Maximum of seven outputs (max/four n-channel

open-drain and three CMOS outputs)

— Time-base output for clock (8 Hz)

• Operating ranges

— Supply voltage ..................................4.5 to 5.5 V

— Opetating temperature ......................–40 to 85°C

• Package
— DIP24S, MFP24S

Package Dimensions

unit: mm

3067-DIP24S

unit: mm

3112-MFP24S

SANYO: DIP24S

[LC72146]

SANYO: MFP24S

[LC72146M]

• CCB is a trademark of SANYO ELECTRIC CO., LTD.

• CCB is SANYO’s original bus format and all the bus
addresses are controlled by SANYO.

Specifications

Absolute Maximum Ratings at Ta = 25°C, VSS= 0 V

Allowable Operating Ranges at Ta = –40 to 85°C, VSS= 0 V

No. 4922-2/21

LC72146, 72146M

Parameter Symbol Conditions min typ max Unit

Supply voltage

V

DD

1 V

DD

4.5 5.5 V

V

DD

2 VDD: Serial data retain voltage 2.0 V

Input high-level voltage

V

IH

1 CE, CL, DI, I/O-1 to I/O-3 2.2 6.5 V

V

IH

2 I/O-4, I/O-5, HCTR/I-6 and LCTR/I-7 2.2 V

DD

V

Input low-level voltage V

IL

1 CE, CL, DI and I/O-1 to I/O-5, HCTR/I-6, LCTR/I-7 0 0.8 V

Input high-leve lvoltage V

IH

3 LCTR/I-7, Pulse wave

*1

2.2 V

DD

V

Input low-level voltage V

IL

2 LCTR/I-7, Pulse wave

*1

0 0.8 V

Output voltage

V

O

1 DO 0 6.5 V

V

O

2 I/O-1 to I/O-3, AOUT, O-7 0 13 V

f

IN

1 XIN; Sine wave, capacitive coupling 1.0 8.0 MHz

f

IN

2 FMIN; Sine wave, capacitive coupling 10 160 MHz

Input frequency

f

IN

3 AMIN; Sine wave, capacitive coupling 0.5 40 MHz

f

IN

4 HCTR/I-6; Sine wave, capacitive coupling 0.4 25 MHz

f

IN

5 LCTR/I-7; Sine wave, capacitive coupling 10 500 kHz

f

IN

6 LCTR/I-7; Pulse wave, DC coupling

*1

1.0 20 × 10

3

Hz

Guaranteed oscillator

Xtal XIN, XOUT; CI ≤ 120 Ω 4.0 8.0 MHz

element frequencies

V

IN

1 XIN 200 1500 mVrms

V

IN

2-1 FMIN; 50 ≤ f < 130 MHz

*2

40 1500 mVrms

V

IN

2-2 FMIN; 10 ≤ f < 50 MHz*2, 130 ≤ f 160 MHz 70 1500 mVrms

V

IN

3-1 AMIN; 2 ≤ f < 25 MHz

*2

40 1500 mVrms

V

IN

3-2 AMIN; 25 ≤ f < 40 MHz

*2

70 1500 mVrms

V

IN

3-3 AMIN; 0.5 ≤ f < 2.5 MHz

*2

40 1500 mVrms

Input amplitude

V

IN

3-4 AMIN; 2.5 ≤ f < 10 MHz

*2

70 1500 mVrms

V

IN

4-1 HCTR/I-6; 0.4 ≤ f < 25 MHz

*3

40 1500 mVrms

V

IN

4-2 HCTR/I-6; 8 ≤ f < 12 MHz

*4

70 1500 mVrms

V

IN

5-1 LCTR/I-7; 10 ≤ f < 400 kHz

*3

40 1500 mVrms

V

IN

5-2 LCTR/I-7; 400 ≤ f < 500 kHz

*3

20 1500 mVrms

V

IN

5-3 LCTR/I-7; 400 ≤ f < 500 kHz

*4

70 1500 mVrms

Data set up time t

SU

DI, CL

*5

0.45 µS

Data hold time t

HD

DI, CL

*5

0.45 µS

Parameter Symbol Conditions Ratings Unit

Maximum supply voltage V

DD

max V

DD

–0.3 to +7.0 V

V

IN

1 max CE, CL, DI –0.3 to +7.0 V

Maximum input voltage V

IN

2 max XIN, FMIN, AIN, AMIN, HCTR/I-6, LCTR/I-7, I/O-4, I/O-5 –0.3 to VDD+ 0.3 V

V

IN

3 max I/O-1 to I/O-3 –0.3 to +15 V

V

O

1 max DO –0.3 to +7.0 V

Maximum output voltage V

O

2 max XOUT, I/O-4, I/O-5, O-6, PD0, PF1, AIN –0.3 to VDD+ 0.3 V

V

O

3 max I/O-1 to I/O-3, AOUT, O-7 –0.3 to +15 V

I

O

1 max I/O-4, I/O-5, O-6, O-7 0 to 3.0 mA

Maximum output current I

O

2 max DO, AOUT 0 to 6.0 mA

I

O

3 max I/O-1 to I/O-3 0 to 10 mA

Allowable power dissipation Pd max

DIP24S:Ta ≤ 85°C 350 mW

MFP24S:Ta ≤ 85°C 220 mW
Operating temperature Topr –40 to +85 °C
Storage temperature Tstg –55 to +125 °C

Continued on next page.

Continued from preceding page.

Note: 1. Period measurement

2. See the description of the structure of the programmable divider.

3. With the CTC bit in the serial data set to 0

4. With the CTC bit in the serial data set to 1

5. See the description of the serial data timing.

Electrical Characteristics at Ta = –40 to +85°C, VSS= 0 V

No. 4922-3/21

LC72146, 72146M

Parameter Symbol Conditions min typ max Unit

Clock low-level time t

CL

CL

*5

0.45 µs

Clock high-level time t

CH

CL

*5

0.45 µs

CE wait time t

EL

CE, CL

*5

0.45 µs

CE setup time t

ES

CL, CE

*5

0.45 µs

CE hold time t

EH

CE, CL

*5

0.45 µs

Chip enable to data latch time t

LC

*5

0.45 µs

Data output time t

DC

DO, CL; Depends on pull-up resistor 0.2 µs

Parameter Symbol Conditions min typ max Unit

Rf1 XIN 1.0 mΩ
Rf2 FMIN 500 kΩ

Internal feedback resistance Rf3 AMIN 500 kΩ

Rf4 HCTR/I-6 250 kΩ
Rf5 LCTR/I-7 250 kΩ

Sub charge pump

R1S AIN 100 Ω

internal resistance
Hysteresis V

HIS

CE, CL, DI, LCTR/I-7 0.1 V

DD

V

I

O

= 0.5 mA VDD– 0.5 V

Output high-level voltage

V

OH

1 PD0, PD1, I/O-4, I/O-5, O-6 IO= 1 mA VDD– 1.0 V

I

O

= 2 mA VDD– 2.0 V

V

OH

2 AIN: IO= 1 mA VDD– 0.6 VDD– 0.3 V

I

O

= 0.5 mA 0.5 V

V

OL

1

PD0, PD1, I/O-4,

IO= 1 mA 1.0 V

I/O-5, O-6, O-7

I

O

= 2 mA 2.0 V

V

OL

2 AIN: IO= 1 mA 0.3 0.6 V

Output low-level voltage

I

O

= 1 mA 0.2 V

V

OL

3 I/O-1 to I/O-3

I

O

= 2.5 mA 0.5 V

I

O

= 5 mA 1.0 V

I

O

= 9 mA 1.8 V

V

OL

4 DO; IO= 5 mA 1.0 V

V

OL

5 AOUT; IO= 1 mA, AIN = 1.3 V 0.5 V

I

IH

1 CE, CL, DI; VI= 6.5 V 5.0 µA

I

IH

2 I/O-1 to I/O-3; VI= 13 V 5.0 µA

Input high-level current

I

IH

3 I/O-4, I/O-5, HCTR/I-6, LCTR/I-7; VI= V

DD

5.0 µA

I

IH

4 XIN; VI= V

DD

2.0 11 µA

I

IH

5 FMIN, AMIN; VI= V

DD

4.0 22 µA

I

IH

6 HCTR/I-6, LCTR/I-7; VI= V

DD

8.0 44 µA

I

IL

1 CE, CL, DI; VI= 0 V 5.0 µA

I

IL

2 I/O-1 to I/O5; VI= 0 V 5.0 µA

Input low-level current

I

IL

3 HCTR/I-6, LCTR/I-7; VI= 0 V 5.0 µA

I

IL

4 XIN; VI= 0 V 2.0 11 µA

I

IL

5 FMIN, AMIN; VI= 0 V 4.0 22 µA

I

IL

6 HCTR/I-6, LCTR/I-7; VI= 0 V 8.0 44 µA

Continued on next page.

Continued from preceding page.

Pin Assignment

Block Diagram

No. 4922-4/21

LC72146, 72146M

Parameter Symbol Conditions min typ max Unit

Output off leakage current

I

OFF

1 I/O-1 to I/O3, AOUT, O-7; VO= 13 V 5.0 µA

I

OFF

2 DO; VO= 6.5 V 5.0 µA

High-level three state

I

OFFH

PD0, PD1, AIN; VO= V

DD

0.01 200 nA

off leakage current
Lowh-level three state

I

OFFL

PD0, PD1, AIN; VO= 0 V 0.01 200 nA

off leakage current
Input cacitance C

IN

FMIN 6 pF

Pull-down transistor

R

pd

1 FMIN 80 200 600 kΩ

on resistance

R

pd

2 AMIN 80 200 600 kΩ

V

DD

; Xtal = 7.2 MHz, fIN2 = 160 MHz,

I

DD

1 VIN2 = 70 mVrms, fIN4 = 25 MHz 10 15 mA

Supply current

V

IN

4 = 40 mVrms

I

DD

2

V

DD

; PLL inhibited,

0.5 1.5 mA

crystal oscillator running (Xtal = 7.2 MHz)

I

DD

3 VDD;PLL inhibited, crystal oscillator stoped 10 µA

Pin Functions

No. 4922-5/21

LC72146, 72146M

Number Symbol Type Function Equivalent circuit

24

1

17

16

2

4

18
23

XIN

XOUT

Xtal OSC

FMIN

Local oscillator

signal input

AMIN

Local oscillator

signal input

CE

Chip enable

CL Clock

DI

Input data

DO Output data

V

DD

Power supply

V

DD

Ground

Connection for crystal oscillator element (7.2 or 4.5 MHz)

• Serial data input: FMIN is selected when DVS is set to 1.
Input frequency range: 10 to 160 MHz

• The signal is transmitted directly to the swallow counter

• Divisor value range: 272 to 65535

• Serial data input: AMIN is selected when DVS is set to 0.

• Serial data input: when SNS is set to 1.

• Input frequency range: 2 to 40 MHz

• The signal is transmitted directly to the swallow counter.

• Divisor value range: 272 to 65535

• Serial data input: when SNS is set to 0.

• Input frequency range: 0.5 to 10 MHz

• The signal is transmitted directly to the 12-bit
programmable divider.

• Divisor value range: 4 to 4095

12
11
10

I/O-1
I/O-2
I/O-3

General-purpose

I/O port

• General-purpose I/O ports

• Output mode circuit type: open drain

• Function after a power on reset: input port

• Can be set up to function as output ports by bits I/O-1 to
I/O-3 in the serial data sent from the controller.

• IThis pin must be set high to input serial data to the
LC72146 DI pin or to output serial data from the DO pin.

• Inputs the clock used for data synchronization when
inputting serial data to the LC72146 DI pin or outputting
serial data from the DO pin.

• Input pin for serial data transmitted to the LC72146 from
a controller.

• Output pin for serial data transmitted from the LC72146 to
a controller.

• The LC72146 power supply connection. A voltage
between 4.5 and 5.5 volts must be supplied when the
PLL circuit is used.

• The power on reset circuit operates when power is first
applied.

Continued on next page.

• The LC72146 ground connection.

3

15

5

Continued from preceding page.

Number Symbol Type Function Equivalent circuit

No. 4922-6/21

LC72146, 72146M

7 O-6

Output port

• The LC72146 latches the OUT6 bit in the serial data and
outputs it from pin O-6.

6 O-7

Output port

• The LC72146 latches the OUT7 bit in the serial data and
outputs it from pin O-7.

• Outputs a time base signal (8 Hz) when TBC is set to 1.

• Function after a power on reset: open circuit

9
8

I/O-4
I/O-5

General-purpose

I/O port

• General-purpose I/O ports

• Output mode circuit type: complementary

• Function after a power on reset: input port

• Can be set up to function as output ports by bits I/O-4
and I/O-5 in the serial data sent from the controller.

20
19

PD0
PD1

Charge pump

output

• PLL charge pump output pin
If the frequency generated by dividing the local oscillator
frequency by N is higher than the reference frequency, a
high level will be output from PD0, and if it is lower, a low
level will be output. PD0 goes to the high-impedance
state when the frequencies match.

• PD1 operates identically.

21
22

AIN

AOUT

Connections for the

low-pass filter

transistor

• Connections to the n-channel MOS transistor used for
the PLL active low-pass filter.

• A high-speed locking circuit can be formed by using
these pins with the built-in sub charge pump.

• See the item on the structure of the charge pump for
details.

Continued on next page.

14 HCTR/I-6

General-purpose

counter

• HCTR is selected when CTS1 is set to 1.

• Input frequency range: 0.4 to 25 MHz

• The signal is passed through a divide-by-two circuit and
then input to a general-purpose counter. This input also
supports an integrating count function.

• The result is output from the DO output pin starting with
the MSB of the general-purpose counter.

• See the item on the structure of the general-purpose
counter for details.

• When the H/I-6 bit in the serial data is set to 0:

• This pin functions as an input port, and the value input is
output from the DO pin.

No. 4922-7/21

LC72146, 72146M

Continued from preceding page.

Number Symbol Type Function Equivalent circuit

13 LCTR/I-7

General-purpose

counter

• LCTR is selected when CTS1 is set to 0.

• If the CTS0 bit in the serial data is set to 1:

• The circuit operates in frequency measurement mode.

• nput frequency range: 10 to 500 kHz

• The signal is directly transmitted to the general-purpose
counter without passing through the divide-by-two circuit.

• If the CTS0 bit in the serial data is set to 0:

• The circuit operates in period measurement mode.

• nput frequency range: 1 Hz to 20 kHz

• The measurement period can be set to be either one or
two periods of the input signal, and if two period
measurement is selected, the input frequency range
becomes 2 Hz to 40 kHz.

• The result is output from the DO output pin starting with
the MSB of the general-purpose counter.

• See the item on the structure of the general-purpose
counter for details.

• When the L/I-7 bit in the serial data is set to 0:

• This pin functions as an input port. The value input is
output from the DO pin.

Functional Description

Serial Data Input

The LC72146/72146M operating parameters are initialized by two 40-bit data words on the serial data input, DI, as
shown in Figure 1 and Figure 2 and Table 1.

Figure 1 Input Data Word IN1

Figure 2 Input Data Word IN2

No. 4922-8/21

LC72146, 72146M

Table 1 Input Data Functions

No. 4922-9/21

LC72146, 72146M

No. Name Function Related bits

Programmable divider ratio
P15 is the MSB. The divider ratio, frequency range and lsb are determined by the setting of the DVS and
SNS flags as shown in Table 2 and Table 3. P0 to P3 are ignored if P4 is the LSB.

Table 2 Divider ratio settings

Note: × = don’t care

Table 3 Frequency range settings

Note: × = don’t care
Sub-charge pump control

Bits PDC0 and PDC1 control the charge pump state as shown in Table 4. The sub-charge pump is
connected to the gate of the low-pass filter transistor. This can be used in conjunction with PD0 and PD1
(main charge pump) to build a fast locking PLL.

Table 4 Charge pump state selection

Note: × = don’t care
* See the “Charge Pump” on page 16 for details.

Reference frequency select
Bits R0 to R3 disable the PLL or select the reference frequency as shown in Table 5.

Table 5 Reference frequency selection

When the PLL is disabled, the programmable divider is stopped, AMIN and FMIN are pulled to ground,
and the charge-pump outputs become high impedance.

DVS SNS LSB Divider ratio (N)

1 × P0 272 to 65535
0 1 P0 272 to 65535
0 0 P4 4 to 4095

DVS SNS Input port Input frequency range (MHz)

1 × FMIN 10 to 160
0 1 AMIN 2 to 40
0 0 AMIN 0.5 to 10

PDC0 PDC1 Charge pump state

0 × High impedance
1 1 Operating (operates continuously)
1 0 Operating (when PLL is unlocked)

R

3

R

2

R

1

R

0

Reference frequency (kHz)
0 0 0 0 100
0 0 0 1 50
0 0 1 0 25
0 0 1 1 25
0 1 0 0 12.5
0 1 0 1 6.25
0 1 1 0 3.125
0 1 1 1 3.125
1 0 0 0 10
1 0 0 1 9
1 0 1 0 5
1 0 1 1 1
1 1 0 0 3
1 1 0 1 30
1 1 1 0 PLL inhibited and crystal oscillator stopped
1 1 1 1 PLL inhibited

P0 to P15,
DVS, SNS

(1)

PDC0,

PDC1

(2)

R0 to R3(3)

UL0, UL1, DLC

Continued on next page.

Continued from preceding page.

No. 4922-10/21

LC72146, 72146M

No. Name Function Related bits

DO and I/O5 output control data
Bits ULD, DT0, DT1, IL0 and IL1 control the mode of outputs DO and I/O5 as shown in Table 6 and Table 7.

Table 6 DO and I/O5 output flag selection

Note: *1. End-UC flags that general-purpose counter operation has finished.

*2.Applicable only if I/O5 is set to be an output port.

Figure 3 DO output state

Table 7 IN state selection

Note: 1. If I/O1 or I/O2 is set to be an output port, IN becomes open.

2. DO does not go low when the crystal oscillator has stopped.

[When reference frequencies are as these: R3 = R2 = R1 = 1; R0 = 0]
Don’t care.
Counter control

Bits CTS0 and CTS1 select the counter input as shown in Table 8.

Table 8 Counter input and measurement mode selection

Note: × = don’t care
Bit CTE starts the counter when 1, and resets the counter, when 0.

Bits GT0 and GT1 select the measurement time in frequency measurement mode or the number of
periods to count in period measurement mode as shown in Table 9.

Table 9 Measurement duration selection

When CTE is 0 the input is pulled down, and when CTP is 1 it is not. (Wait time: 1 to 2 ms.)
CTP must be set to 1 at least 4 ms before CTE is set to 1.
The input sensitivity can be reduced by setting CTC to 1. (Sensitivity: 10 to 30 mV rms)

(4)

ULD, DT0,

DT1, IL0, IL1

(6)

(5)

CTS0,

CTS1, CTE,

GT0, GT1

*

CTP, CTC

OUT5, I/O1, I/O2, I/O5

H/I6, L/I7

ULD DT1 DT0 DO I/O5

0 0 0 Unlock flag
0 0 1 Open

OUT5 flag

*

2

.

0 1 0 End-UC flag

*1

.
0 1 1 IN. See table 7.
1 0 0 Open
1 0 1 Open

Unlock flag

*

2

.

1 1 0 End-UC flag
1 1 1 IN. See table 7.

IL1 IL0 IN state

0 0 Open
0 1 I1 input
1 0 I2 input
1 1 DO goes low when I1 changes.

CTS1 CTS0 Input

Measurement

mode
1 × HCTR Frequency
0 1 LCTR Frequency
0 0 LCTR Period

Frequency measurement Period measurement

GT1 GT0 Measurement

Wait time (ms) Cycles

duration (ms)

0 0 4

3 to 4 1

0 1 8
1 0 32

7 to 8 2

1 1 64

Continued on next page.

Continued from preceding page.

No. 4922-11/21

LC72146, 72146M

No. Name Function Related bits

Input/output port control
Bits I/O1 to I/O5 set the direction of the ports. Each pin is an input when the corresponding bit is 0,
and an output, when the bit is 1. All ports are set to be inputs after power-on reset.

Output port data
Bits OUT1 to OUT7 set the output values of the O-1 to O-7 output ports. Each output is open or high when
the corresponding bit is 1, and low, when the bit is 0. A bit is ignored if the corresponding port is an input
port or the unlock output.

Counter input control
Bits H/I-6 and L/I-7 select the operation of the HCTR/I-6 and LCTR/I-7 pins. When H/I-6 is 0, HCTR/I-6 is an
input port, and when H/I-6 is 1, HCTR/I-6 is the HCTR input. When L/I-7 is 0, LCTR/I-7 is an input port, and
when L/I-7 is 1, LCTR/I-7 is the LCTR input.

PLL unlock detect control
Bits UL0 and UL1 select the phase error threshold and extension (øE) used to detect the PLL unlocked
state as shown in Table 10 and Figure 4. When the phase error is greater than the selected error, the PLL
unlock detector output goes low.

Table 10 Unlock detection and extension selection

Figure 4 Phase-error extension

Crystal oscillator control
Bit XS selects the oscillator frequency. When XS is 1, the frequency is 7.2 MHz, and when XS is 0,

4.5 MHz.

4.5 MHz is selected after power-on reset.
Phase comparator control

Bits DZ0 and DZ1 select the phase comparator insensitive band, or dead zone.

Table 11 Insensitive band mode selection

DZA is selected after power-on reset.
Charge pump control

Bit DLC controls the charge pump operation. When DLC is 1, the charge pump outputs are forced to low,
and when DLC is 0, the charge pump operates normally.
This feature can be useful to remove the PLL from a deadlock state. The PLL can deadlock if its VCO
control voltage V

tune

becomes 0 V, halting the VCO. Setting DLC to 1 sets V

tune

to VCC, restarting the VCO.

Normal operating mode is selected after power-on reset.
An 8 Hz 40% duty clock time base signal can be output from pins 0 to 7 by setting TBC to 1.

When TBC is 1 the OUT7 data will be invalid. TBC is set to 0 by the power-on reset.
Test data

Bits TEST0 to TEST2 are used for in-factory device testing. Set them all to 0. They are set to zero after a
power-on reset.

(7)

(8)

I/O1 to I/O5

OUT1 to

OUT7

(9) H/I6, L/I7

(10) UL0, UL1

(11) XS

(12) DZ0, DZ1

(15)

TEST0 to

TEST2

(14) TBC

(13) DLC

OUT1 to OUT5, ULD

I/O1 to I/O5, ULD

CTS0, CTS1

ULD, DT0, DT1

OUT7

UL1 UL0 Phase error Detector output

0 0 Stopped Open
0 1 0 øE output
1 0 ±0.56 µs øE with 1 to 2 ms extension
1 1 ±1.11 µs øE with 1 to 2 ms extension

DZ1 DZ0 Insensitive band (dead zone) mode

0 0 DZA
0 1 DZB
1 0 DZC
1 1 DZD

Serial Data Output

The 40-bit data word output on DO has the format and functions as shown in Figure 5 and Table 12, respectively.

Figure 5 Output Data Word Out

Table 12 Input Data Functions

Serial Data Input/Output Mode Selection

The LC72146/M use the CCB (computer control bus) serial data format. The first eight bits form the address, shown in
Figure 6, used to select the mode of operation as shown in Table 13.

Table 13 Serial Data Input/Output Mode Selection

No. 4922-12/21

LC72146, 72146M

No. Name Function Related bits

Input port data
Bits I-1 to I-7 reflect the data latched into each input port when the device changes to data output mode.
I6 and I7 are zero when the corresponding port is a counter input. I1 to I5 correspond to the I/O1 to I/O5
ports, and I6 and I7, to the HCTR/I6 and LCTR/I7 inputs, respectively.

Counter contents
Bits C0 to C19 are the latched contents of the 20-bit binary counter. C19 is the msb. C0 is the lsb.

(1) I1 to I7

(2) C0 to C19

I/O-1 to I/O-5, H/I-6,

L/I-7

OUT1 to OUT5

CTS0, CTS1, CTE

Input/output mode

Address

Function

B0 B1 B2 B3 A0 A1 A2 A3
IN1 0 0 0 1 0 0 1 0 32-bit control data input
IN2 1 0 0 1 0 0 1 0 32-bit control data input

OUT 0 1 0 1 0 0 1 0 Output data. Data is output if the clock is active.

1. Serial data input (IN1/IN2)

2. Serial data output (OUT)

Note: 1. The data conversion time varies with the value of the pull-up resistor, since the DO pin is an n-channel open drain circuit.

2. The DO pin is normally open.

Programmable Divider

The configuration of the programmable divider is shown in Figure 7. The input mode selection is shown in Table 14, and
the input sensitivity, in Table 15.

Figure 7 Programmable Divider

Table 14 Programmable Divider Selection

Note: × = don’t care

No. 4922-13/21

LC72146, 72146M

DVS SNS Divisor setting (NO) Input frequency range Input port

1 × 272 to 65535 10 to 160 MHz FMIN
0 1 272 to 65535 2 to 40 MHz AMIN
0 0 4 to 4095 0.5 to 10 MHz AMIN

Table 15 Input Sensitivity (Target Sensitivity)

CTC: Input sensitivity switching data. When CTC is 1 the input sensitivity is degraded.However, the actual values will be:

HCTR → 30 to 40 mVrms (frequency: 10.7 MHz)
LCTR → 10 to 15 mVrms (frequency: 450 kHz)

CTP: The input pull-down resistor (when CTE is 0) can be disabled by setting CTP to 1.

CTP must be set to 1 at least 4 ms before CTE is set to 1. CTP should be set to 0 if the counter is not used.
When CTP is set to 1 wait time is reduced at 1 to 2 ms.

The LC72146 includes a general-purpose 20-bit binary counter whose value can be read out from the DO pin, msb first.
When using this counter for frequency measurement, one of four measurement times (4, 8, 32, or 64 ms) is selected by
GT0 and GT1. The frequency input to either the HCTR or the LCTR pin can be measured by determining the number of
pulses input to the counter during the measurement period.
This counter can be used to measure the period of the signal input to the LCTR pin by determining how many cycles of a
reference signal (900 kHz) are input to the counter during one or two periods of the LCTR pin signal.
The counter is started by setting the serial data CTE bit to 1. While serial data is latched in the LC72146 when CE falls
from high to low, input to the HCTR or the LCTR pin must be provided within the waiting period that follows CE being
set low.
Next, after the measurement completes, the value of the counter must be read out during the period that CTE is 1. (The
general-purpose counter is reset when CTE is set to 0.)
It should be emphasized here that the counter should be reset before measurement by setting CTE to 0.
Also note that although the signal input to the LCTR pin is input to the counter directly, the signal input to the HCTR pin
is divided by two internally before being input to the counter. Accordingly, the value of the counter will be 1/2 the actual
frequency input to the HCTR pin.

Figure 8 General-Purpose Counter

No. 4922-14/21

LC72146, 72146M

Minimum input sensitivity (f [MHz])

(A) FMIN

10 ≤ f < 50 50 ≤ f < 130 130 ≤ f < 160

70 mVrms 40 mVrms 70 mVrms

(B) AMIN

2 ≤ f < 25 25 ≤ f < 40

—

40 mVrms 70 mVrms

(C) AMIN

0.5 ≤ f < 2.5 2.5 ≤ f < 10
—

40 mVrms 70 mVrms

Note: * CTC = 0: 40 mVrms

CTC = 1: 70 mVrms
However, the frequency ranges will be as follows when CTC is 1.
HCTR: 8 to 12 MHz, LCTR: 400 to 500 kHz

Integrating Count

Note: CTE: 0 → • General-purpose counter reset

1 →

• General-purpose counter start

• Restarts on a new 1 setting
In integrated count mode, the count value is accumulated in the general-purpose counter.
Care is required to handle counter overflow.
Counter values: 0

H

to FFFFFH(1,048,575)
To implement the integrating count operation leave CTE set to 1. When the serial data (IN1) is transmitted again, the general-purpose counter will
start to measure the input again and the result will be added to the count.

No. 4922-15/21

LC72146, 72146M

CTS1 CTS0 Input pin Measurement mode Frequency range Input sensitivity
S1 1 — HCTR Frequency 0.4 to 25.0 MHz 40 mVrms*
S2 0 1 LCTR Frequency 10 to 500 kHz 40 mVrms*
S3 0 0 LCTR Period 1.0 to 20 × 10

3

Hz (pulse)

GT1 GT0

Frequency measurement mode

Period measurement

Measurement time (ms) Wait time (ms)

mode

0 0 4

3 to 4 One period

0 1 8
1 0 32

7 to 8 Two periods

1 1 64

Charge Pump

The charge pump configuration is shown in Figure 9.

Figure 9 Charge Pump

When unlock is detected following a channel change, PDS (the sub-charge pump) operates. The value of R1 changes to
R1M // R1S (R1S ≈ 100 Ω), as shown in Figure 10, decreasing the low-pass filter time-constant and accelerating PLL
locking.

Figure 10 Charge Pump Connections

No. 4922-16/21

LC72146, 72146M

PDC1 PDC0 PDS (sub-charge pump state)

0 — High impedance
1 1 Charge pump operates (normal operation)
1 0 Charge pump operates (when unlocked)

DLC PD1, PD0, PDS

0 Normal operation
1 Forced to low

The unlock detection data UL1 must be set to 1. The unlock detection range will be set to ±0.56 µs or ±1.11 µs. If a
phase difference in excess of these values is detected the circuit will go to the unlock state and the sub-charge pump will
operate. When the circuit approaches the lock state and the phase difference falls under the unlock detection range, the
sub-charge pump operation will stop, i.e., the sub-charge pump will go to the high impedance state.

Note: 1. Notes on the phase comparator dead zone

Cases where the charge pump is in the ON/ON state require special care during system design since the charge
pump outputs correction pulses even when the PLL is locked and it is easy for the loop to become unstable.
The following problems may occur in the ON/ON state.

① Sidebands may be generated by reference frequency leakage.
② Sidebands may be generated by low frequency leakage due to the correction pulse envelope.

The settings that have a dead zone (the OFF/OFF settings) provide good loop stability, but it is hard to achieve
a good S/N ratio with these settings. Inversely, the settings with no dead zone (the ON/ON settings) allow a
high S/N ratio to be achieved but it is hard to achieve good loop stability with these settings.
Therefore, it can be effective to select either the DZA or DXB setting, i.e., a setting which has no dead zone,
when an S/N ratio of between 90 and 100 dB or higher is required in FM mode, or when the AM stereo pilot
margin needs to be increased. However, in cases where such a high FM S/N ratio is not required and where an
adequate AM stereo pilot margin can be achieved or AM stereo is not used, either the DZC or DZD setting,
i.e., a setting which has a dead zone, should be selected.

Dead Zone Definition
The phase comparator compares fp with a reference frequency (fr) as shown in Figure 11. Figure 12 shows the
characteristics of an ideal phase comparator, which outputs an output voltage (A) that is proportional to the
phase difference ø. However, in an actual IC, a region (dead zone) in which minute phase differences cannot
be detected occurs due to internal circuit delays and other factors. To implement an end product with a high
S/N ration, the dead zone should be as small as possible.
However, there are cases where a larger dead zone can make a popularly-priced model easier to use. This is
because it is possible for RF leakage from the mixer to the VCO to modulate the VCO in popularly-priced
models when a strong RF input is applied. When the dead zone is small an output that compensates for this
problem is generated, and this output may itself modulate the VCO and generate beating with the RF
frequency.

No. 4922-17/21

LC72146, 72146M

DZ1 DZ0 Dead zone mode Charge pump Dead zone

0 0 DZA ON/ON – –0 s
0 1 DZB ON/ON –0 s
1 0 DZC OFF/OFF +0 s
1 1 DZD OFF/OFF + +0 s

Figure 11 Figure 12

2. FMIN, AMIN, HCTR and LCTR
These inputs should each be capacitively coupled using a 50 to 100 pF capacitor. Also, these capacitors should
be mounted as close as possible to their respective inputs.

3. IF counting using HCTR or LCTR
The LC72146 can perform IF count tuning when connected to an SD (station detector) signal from an IF IC.
IF counting should start when the SD signal becomes active.
Note on IF counting: The SD (station detect) signal must be used in conjunction with IF counting.
When using the general-purpose counter for IF counting, be sure to determine whether or not there is an SD
signal from the IF IC. The IF counter buffer should be turned on and IF counting performed only if there is an
SD signal. 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.

4. Using the DO pin
In modes other than data output mode, the DO pin is also used for counter completion, unlock detection, and for
checking for changes in the input pin. (In these cases the DO pin will change from the high to the low level.)
The state of the input pin can be input to the controller directly through the DO pin.

Pin States at Power On and Reset

No. 4922-18/21

LC72146, 72146M

Application System Example

Note on Clock Time Base Usage

A resistor of at least 100 kΩ must be used as the clock time base output pin (O-7) pull-up resistor. Also, the use of a
Schmitt circuit is recommended in the controller (microprocessor) input circuit to prevent chattering. Forming a loop
filter with the built-in low-pass filter transistor will also serve to prevent degradation of the VCO C/N characteristics.
Since the grounding points for the clock time base output pin and the low-pass filter transistor are a common point
within the IC, current fluctuations in the clock time base output pin must be kept to a minimum to limit influencing the
low-pass filter.

No. 4922-19/21

LC72146, 72146M

No. 4922-20/21

LC72146, 72146M

Serial Data Timing

No. 4925-21/21

LC72146, 72146M

This catalog provides information as of July, 1996. Specifications and information herein are subject to change
without notice.

■ No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace
equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of
which may directly or indirectly cause injury, death or property loss.

■ Anyone purchasing any products described or contained herein for an above-mentioned use shall:
➀ Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and

distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all
damages, cost and expenses associated with such use:

➁ Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on

SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees
jointly or severally.

■ Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for
volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied
regarding its use or any infringements of intellectual property rights or other rights of third parties.