Pin Functions

No. 4758-6/16

LC7218, 7218M, 7218JM

Pin No.

Symbol

I/O

Type

Function

1

24

19

18

21

22

6

20

23

2

4

3

5

FMIN

AMIN

PD1

PD2

SYC

CE

CL

DI

DO

Input

Output

Input

Input

Three-state

N-channel

open drain

—

—

Input*

Input*

Input*

Output

(N-channel

open drain)

Xtal OSC

Local oscillator signal

input

Local oscillator signal

input

Charge pump outputs

Controller clock

Power supply

Ground

Chip enable

Clock

Input data

Output data

• Connections for a 7.2 MHz crystal oscillator

• FMIN is selected when DV in the serial input data is set to 1.

• Input frequency range: 10 to 130 MHz (70 mVrms minimum)

• The signal passes through an internal divide-by-two prescaler and is then supplied to

the swallow counter.

• Although the divisor setting is in the range 256 to 65,536, the actual divisor will be twice

the set value due to the presence of the internal divide-by-two prescaler.

• AMIN is selected when DV in the serial input data is set to 0.

• When SP in the serial input data is set to 1:

— Input frequency range: 2 to 40 MHz (70 mVrms minimum).

— The signal is supplied directly to the swallow counter without passing through the

internal divide-by-two prescaler.

— The divisor setting is in the range 256 to 65,536 and the actual divisor will be the

value set.

• When SP in the serial input data is set to 0:

— Input frequency range: 0.5 to 10 MHz (70 mVrms minimum).

— The signal is supplied directly to a 12-bit programmable divider.

— The divisor setting is in the range 4 to 4,096 and the actual divisor will be the

value set.

• PLL charge pump outputs. High levels are output from PD1 and PD2 when the local

oscillator frequency divided by n is higher than the reference frequency, and low levels

are output when that frequency is lower than the reference frequency.

These pins go to the floating state when the frequencies agree.

• SYC is a controller clock source. The LC7218 outputs a 400 kHz 66% duty signal

from this pin after power is applied.

• The LC7218 power supply pin. A voltage of between 4.5 and 6.5 V must be provided

when the PLL is operating. The supply voltage can be lowered to 3.5 V when only

operating the crystal oscillator circuit to acquire the controller clock and the clock time

base outputs.

• The LC7218 ground pin

• This pin must be set high when inputting serial data (via DI) or when outputting serial

data (via DO).

• The clock input used for data signal synchronization during serial data input (via DI) or

output (via DO).

• Input pin used when transferring serial data from the controller to the LC7218.

• A total of 36 bits of data must be supplied to set up the LC7218 initial state.

• Output pin used when transferring serial data to the controller from the LC7218.

• A total of 28 bits from an internal shift register can be output in synchronization with the

CL signal.

Continued on next page.