TONE/PULSE DIALER WITH REDIAL

S5T5820C

INTRODUCTION

The S5T5820C is a DTMF/PULSE switchable dialer with a 32-digit
redial which can be done using a slide switch. All necessary dual-tone
frequencies are derived from a 3.579545 MHz TV crystal or ceramic
resonator providing very high accuracy and stability. The required
sinusoidal wave form for each individual tone is digitally synthesized
on the chip. The generated wave form has very low total harmonic
distortion (7% max). A voltage reference is generated on the chip
which is stable over the operating voltage and temperature range and
regulates the single levels of the dual tone to meet telephone industry
specifications. CMOS technology is applied to this device, for very low
power requirements high noise immunity, and easy interface to a
variety of telephones requiring external components.

FEATURES

Tone/Pulse switchable (slide switch)

32-digit capacity for redial

Automatic mix redialing ( last number dial )

PULSE

DTMF with multiple auto access pause

PABX auto-pause for 3.5 sec.

4 X 4 or ( 2 of 8 ) keyboard available

Two key single tone operation

Operating Voltage : 2.0 to 5.5V

Numbers dialed manually after redial are cascadable and stored as additional numbers for next redialing

Uses inexpensive TV crystal or ceramic resonator (3.579545MHz)

Make/Break ratio (33.3 / 66.6) pin selectable

Touch key hooking (604ms)

Low standby current

Improved EMI characteristics

Improved redial memory quality

ORDERING INFORMATION

Device

Package

Operating Temperature

S5T5820C03-D0B0

DIP

300A

C to + 70

S5T5820C03-S0B0

SOP

375

DIP

300A

SOP

375

TONE/PULSE DIALER WITH REDIAL

S5T5820C

PIN CONFIGURATION

S1T5820C

M/B

MDS

OSC IN

OSC OUT

TONE OUT

MUTE

(18 DIP)

S5T5820C

M/B

MDS

OSC IN

OSC OUT

TONE OUT

MUTE

(20 SOP)

S5T5820C

TONE/PULSE DIALER WITH REDIAL

ARRANGEMENT OF KEYBOARD

TONE FREQUENCIES

* Keyboard Description

Input

Specified

Actual

% Error

697

699.1

+ 0.31

770

766.2

0.49

852

847.4

0.54

941

948.0

+ 0.74

1209

1215.7

+ 0.57

1336

1331.7

0.32

1477

1471.9

0.35

: HOOKING (604ms)

: PAUSE (3.5 second)

: REDIAL

TONE/PULSE DIALER WITH REDIAL

S5T5820C

PIN DESCRIPTION

Pin No

Symbol

Description

Keyboard (R1, R2, R3, R4, C1, C2, C3, C4)
These inputs can be interfaced to an XY matrix keyboard. C1

C4 & R1

R4 are set

to low at On Hook (HS = high). C1

C4 key inputs are set to low and R1-R4 are set

to high at OFF HOOK (HS = low) which enables the key-input operation. The
oscillator starts running when a key-press is detected. Scanning signals are
presented at both column and row inputs (Typ: 437Hz) until the input key is
released. Key inputs are compatible with standard 2-of-8 form or a single-contact
keyboard. Debouncing is provided to avoid false entry (Typ: 4mS).

Hook Switch
This input detects the state of the hook switch contact.
Off Hook corresponds to V

condition. On Hook corresponds to V

condition.

M/B

Make/Break Ratio
This input provides the selection of the Make/Break ratio (33.3: 66.6/40:60)
when M/B is connected to V

MDS

Mode Select Input
Pulse/DTMF mode is selected as shown is the following table. Initial Mode means
the state after going Off Hook (

)

OSC IN
OSC OUT

Oscillator Input/Output
These pins are provided to connect an external 3.58MHz crystal. Oscillator starts (at
Off Hook) and is sustained until pulse or DTMF signals are finished.

, V

Power supply inputs.
The device is designed to be operated on 2.0V to 5.5V

TONE OUT

DTMF Signal Output
When a valid keypress is detected in DTMF mode, appropriate low and high group
frequencies are generated which hybrid the Dual Tone Output. Tone out is Off State
in pulse mode.

MUTE

MUTE Output

(N channel open drain)

Dial Pulse Out

: The normal output will be ON during break and OFF during make at OFF

HOOK. The output will be OFF at ON HOOK.

MDS

INITAL MODE

SWITCHING ENTRY MODE

Pulse

MDS Input = V

Tone

N/A

X'MUTE

Output

Normally OFF ON during pulse and DTMF dialing

S5T5820C

TONE/PULSE DIALER WITH REDIAL

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

= 0V, V

= 3.5V, f

XTAL

= 3.579545MHz, Ta = 25

C, unless otherwise specified)

Characteristic

Symbol

Value

Unit

Supply Voltage

6.0

Input Voltage

- 0.3, V

+ 0.3

Output Voltage

- 0.3, V

+ 0.3

Output Voltage

O (DXM)

(DP, X

MUTE, MUTE)

Tone Output Current

O (TONE)

Power Dissipation

500

Operating Temperature

OPR

20 to + 70

Storage Temperature

STG

40 to + 125

Characteristic

Symbol

Test Conditions

Min.

Typ.

Max.

Unit

Operating Voltage Range

2.0

5.5

Memory Retention Voltage

1.0

Memory Retention Current

= V

= 1.0V

0.05

0.1

Operating Current

DD (PULSE)

MDS

= V

One selected

Vss, All outputs
unloaded

0.1

0.3

DD (TONE)

MDS

= V

0.4

0.7

Standby Current

= V

No key selected. all
outputs unloaded

Output Current

OL1

= 3.5V

1.7

5.0

OL2

X'MUTE

= 2.5V

0.5

1.5

Input Voltage

, M/B

0.8V

MDS

0.2V

Input Current

= 3.5V, V

= 0V

= 2.5V, V

= 0V

Valid Key Entry Time

Key Release Time

Tone Duration

110

Tone Interdigit Pause Time

TIDP

110

Column and Row Scanning
Frequency

437

Auto Access Pause Time

3.5

sec

Tone Output

D(TONE)

ROW TONE
ONLY

= 2.5V, R

= 5k

14.0

12.0

dBV

= 3.5V, R

= 5k

14.0

12.0

Ratio of Column to Row Tone

= 3.5V

1.0

2.0

3.0

Distortion

THD

= 3.5V

Tone Output Delay Time

D(TONE)

1.5

TONE/PULSE DIALER WITH REDIAL

S5T5820C

APPLICATION INFORMATION

KEYBOARD OPERATION

Single Mode Operation

Pulse Mode Operation

The pulse mode is defined by the initial mode after going off Hook and latched at D1 key entry.
This is the condition under MDS = V

Tone Mode Operation

The tone mode is defined by the initial mode after going off Hook and latched at D1 key entry.
This is the condition under MDS = V

Manual Dialing with Automatic Access Pause

Multiple Pause key entries can be accepted and stored in the redial memory, each as a digit. Each P key provides
3.5 seconds pause time, but the P key entry as the first digit after going Off Hook is ignored. The * key can also
be used as a pause key in the pulse mode.
Pause (2) can be cancelled with the P or RD key during pause time in redialing.
D = Any numeric key.

Redialing

Up to 32 digits can be dialed with the RD key.
The RD key is disabled while pulse or DTMF signals are transmitted.
When more than 32 digits are stored, redial is also inhibited.
The # key can be used as the RD key in the pulse mode.

Inhibiting Redial

Redial can be inhibited by pressing the RD key twice after DTMF or pulse signals are transmitted.

Off Hook

.....

Off Hook

.....

Off Hook

.....

Off Hook

.....

S5T5820C

TONE/PULSE DIALER WITH REDIAL

PULSE/TONE SWITCHABLE OPERATION

Mode Switching by

MDS

Input

The pulse mode is initially defined MDS = V

. Mode switching to the DTMF mode can be accepted by MDS = V

The DTMF mode will be set up after the pulse mode is finished. In this mode, digits Dn + 1 ... Dn + m are
transmitted from Tone Out as DTMF signals by pressing the corresponding keys.
If no P key is contained serially before or after mode switching, the following condition is obtained.

If digit Dn+1 is depressed after the pulse mode is finished, the DTMF mode will be set up after last the pulse signal
( Dn ) is generated. In this mode,digits Dn+1 ... Dn+m are transmitted from Tone Out as DTMF signals by
pressing the corresponding keys. If digit Dn+1 is pressed during dialing pulse signals.
What happens? When the DTMF mode is set, the Hold State will be set after last pulse signal Dn is finished. MDO
will flash to indicate this Hold State, Dn+1 ... Dn+m are stored in redial memory as DTMF DATA and not transmitted
from Tone Out. When it is ready to transmit DTMF data in redial memory, the RD or P key is pressed to reset this
Hold State and Dn+1 ... Dn+m data are serially transmitted.

Off Hook

.....

Switching MDS to Vss

Dn+1

...

Dn+m

pulse mode

DTMF mode

Off Hook

.....

Switching MDS to Vss

Dn+1

...

Dn+m

pulse mode

DTMF mode

(Dn+1

Pause)

Document Outline

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Document Outline

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: S5T5820C03-S0B0