TONE / PULSE SWITCHABLE DIALER
WITH HANDFREE FUNCTION
DESCRIPTION
The SC91710A/B are Tone/Pulse switchable dialer which are
fabricated in COMS technology with wide operating voltage for both
tone and pulse mode, and consumes very low memory retention
current in ON-HOOK state.
FEATURES
*Tone/Pulse switchable dialer
*One 32-digit last number redial memory
*Pulse-to-tone (P→T) is provided for PBX operation
*Flash key is available
*Minimum tone duration is 98ms or 83ms
*Minimum intertone pause is 98ms or 83ms
*Redial Pause time (0ms)
*Uses 3.579549MHz crystal or ceramic resonator
*Many options can be selected
Mode (10PPS; 20PPS; Tone)
M/B ratio (40:60;33:66)
Pause time (3.6s)
*Flash function (RESET)
(P→T) pause time (3.6s)
Flash time (600ms; 300ms; 100ms; or 80ms)
PIN CONFIGURATION
SC91710A/B
DIP-16
DIP-18
*Mixed dialing
*Power on reset circuit is provided
*Handfree function is provided for speaker
pin is LOW, the column group stays in “HIGH” state and row group
HKS
stays in “LOW” state.
*The keypad is compatible with the standard dual contact matrix keyboard
(as figure1b), the inexpensive single contact keyboard (as figure 1a), and
electronic input (as figure 1c).
*When
Column connection or by electronic input (as shown in figure 1c).
*Activation of two or more keys will result in no response, except for single
key.
*To avoid keyboard-bouncing error, this chip provides built-in debounce
circuit. (The debounce time = 20ms)
Figure1a: Single contact form
is “LOW”, a valid key entry is defined by related Row &
HKS
Row
keyboard configuration
Row
Column
Figure1c: Electronic signal input keyboard configuration
Column
Figure1b: Dual contact form
Row
Column
keyboard configuration
V
DD
V
SS
V
DD
V
SS
*Oscillator input & output pins.
55OSCI
66OSCO
*The 3.579545MHz oscillator is formed by a built-in inverter inside of this
chip and by connecting a 3.579545MHz crystal or a ceramic resonator
across the OSCI and OSCO pins. (built-in feedback resistor and capacitor)
*When
generates a 3.579545 MHz clock.
is “LOW”, a valid key-in may turn on this oscillator and
88VSS*Negative power supply pin.
911VDD*Positive power supply pin.
1012
1113
1214TONE
Pin Name Description
7
XMUTE
HKS
9
10HFO
PO
HFI
*Mute output pins.
*NMOS open drain output structure.
*The output is in “LOW” state during dialing sequence (both Pulse and
Tone
mode) otherwise this pin is “high-impedance”.
*Long (continue) Mute.
*Hook switch input pin.
*When the handset is in ON-HOOK state, this pin must be pulled “high” in
order to disable the dialing operation and decrease the power
consumption.
*When in OFF-HOOK state, the
all function operation.
*Pulse output signal pin.
*NMOS open drain output structure.
*The output is “LOW” during pulse dialing and Flash operation, otherwise
this output is “floating”.
*Dual ToneMulti-frequency output pin.
*In TONE mode, when an entry of digit key (include *, # key), this pin will
send out a corresponding DTMF signal.
*The TONE pin provides minimum tone duration and minimum intertone
pause time to support rapid key-in. If key-in time is less than 100ms,
DTMF signal will last for 100ms; otherwise the tone duration will last as
long as the key is pressed.
* Handfree input control pin.
* Toggleinput structure, falling edge trigger.
* It is used to enable and disable Handfree function.
* With waveshaped by a built-in Schmit trigger, the bounce of input can be
eliminated by external R, C debounce circuit.
* A built-in pull down resistor is 200k typical.
* Handfree output control pin.
* Inverter output structure (normally ‘low’, active ‘high’).
* When a HFI pin is active, Handfree function will be enabled (HFO=1) or
disable (HFO=0).
* When the Handfree function is enable (HFO=1), after OFF-HOOK action,
it can reset Handfree function and HFO pin return to ‘low’ state.