LC737212 Ver la hoja de datos (PDF) - SANYO -> Panasonic

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LC737212

Telephone Dialer IC with On-Chip Memory for PushButton Telephones

SANYO -> Panasonic 

LC737212, 737212M

• SOUT-ENA

Normaly set high. Serial output and Dial output are enabled when this pin is set high.

• HOLD OFF IN

Hold mode is cleared when a falling edge is detected on this pin. HOLD-OFF pin inputs are not accepted for the 0.5

seconds immediately following a transition to on-hook hold mode.

• ON-HOOK-DIAL IN

This pin toggles an on/off state on each input falling edge. When the telephone is on hook, this pin toggles the on/off

state of on-hook dialing mode. When the telephone is off hook, this pin toggles the on/off state of monitor mode.

• SI/KEY

The keypad is set to input mode when this pin is set low. When this pin is set high, serial input is enabled. In this state,

all keypad inputs are pulled up by built-in resistors, and the pins C6 to C8 function as the serial interface input pins.

C6 = serial clock input

C7 = serial data input

C8 = strobe input

• OFF-HOOK

This pin is the hook state switching input.

• DPR

This pin is the dialing pulse rate switching input. (H: 20 pps, L: 10 pps)

• P/T

This pin is the dialing signal switching input. (H: pulse, L: DTMF) This pin can only switch from pulse to DTMF. This

allows mixed-mode dialing, i.e. switching modes during dialing.

• DISCON IN

Setting this pin low switches the LC737212/M to low power mode and forcibly stops the oscillator circuit. All outputs

are turned off in low power mode. (The n-channel open-drain outputs go to the high-impedance state, and the

complementary outputs go low.) The internal states of the LC737212/M are reset when this pin goes high.

Off-hook input

H

H

L

L

On-hook Dial input

H

L

H

L

Status

STANDBY

ON-HOOK DIAL

OFF-HOOK DIAL

MONITOR

We recommend setting the DISCON pin low when power is first applied, and setting it high after the power-supply

voltage (VDD) has reached or exceeded 1.5 volts.

1 to 10 kΩ

0.1 to 10 µF

• BMR

This pin sets the break/make ratio for the dialing pulse output. (H: 33.2%, L: 39.2%)

• OFF/ON-HOOK STORE

This pin switches the memory storing mode.

H: Off-hook store (Memory stored with the telephone line connected.)

L: On-hook store (Memory stored with the telephone line disconnected.)

No. 5203-9/27

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