No. 4796-9/13

LC72321

Continued from preceding page.

Pin

Pin No.

Function

I/O

I/O circuit type

HCTR

LCTR

ADI

INT

EO1

EO2

SNS

HOLD

RES

XIN

XOUT

TEST1

TEST2

70

71

69

66

77

78

72

67

68

1

80

2

79

31, 73

76

Universal counter input

The input should be capacitor-coupled.

The input frequency range is from 0.4 to 12 MHz.

This input can be effectively used for FM IF or AM IF counting.

Universal counter input

The input should be capacitor-coupled for input frequencies in

the range 100 to 150 kHz.

Capacitor coupling is not required for input frequencies from

1 Hz to 20 kHz.

This input can be effectively used for AM IF counting.

This pin can also be used as a normal input port.

A/D converter input

A 1.28 ms period is required for a 6-bit sequential comparison

value of 3FH.

External interrupt request input

An interrupt is generated when the INTEN flag is set (by an

SS instruction) and a falling edge is input.

This pin can also be used as a normal input port.

Reference frequency and programmable divisor phase

comparison error outputs

Charge pump circuits are built in.

EO1 and EO2 are the same.

Input pin used to determine if a power outage has occurred in

BACKUP mode

This pin can also be used as a normal input port.

Input pin used to force the LC72322 to HOLD mode

The LC72322 goes to HOLD mode when the HOLDEN flag is

set (by an SS instruction) and the HOLD input goes low.

A high breakdown voltage circuit is used so that this input can

be used in conjunction with the normal power switch.

System reset input

This signal should be held low for 75 ms after power is first

applied to effect a power-up reset.

The reset starts when a low level has been input for at least

six reference clock cycles.

Crystal oscillator connections

(4.5 MHz)

A feedback resistor is built in.

Power supply

Input

Input

Input

Output

Input

Input

Input

Input

Output

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