sames
SA589
LD/DTMF SWITCHABLE DIALLERS
WITH DEDICATED KEYS FOR 20 MEMORIES
FEATURES
n
Selectable Loop-Disconnect or DTMF
Modes
n
Keypad Switchable LD to DTMF
n
20 x 24-Digit Memories, (each with
Dedicated Key)
n
24 Digit Last Number Redial
n
Selectable Make/Break Ratios 2:1 and 3:2
DESCRIPTION
The SA589 family are keypad switchable LD/
DTMF dialler devices with a last number
redial facility and twenty 24-digit memories
each with its own dedicated dialling key.
Three operating modes are available: LD
only mode, DTMF only mode and LD mode
with the ability to switch temporarily to DTMF
mode from the keypad during a call. This last
mode enables subscribers to access such
services as home banking. Mixed LD and
DTMF numbers can also be stored in memory.
The SA589 devices are pin compatible with
the SAMES switchable dialler families SA541,
SA545, SA585, SA587 and SA588 - providing
a complete range of telephone features within
a single PCB and circuit design. Metal mask
and pin selectable options are available to
service specific requirements of particular
countries and customers.
n
Uses Inexpensive 560kHz Ceramic
Resonator
n Batteryless operation - Low Power CMOS
n Mask Programmable Options to suit
application
n Timed Break Recall (Flash) and Earth
Recall
FIG. 1 PIN CONNECTIONS
SA589
NC
1
28
ROW7
COL6
2
27
COL5
IMP
3
26
COL4
SELECT
4
25
ROW4
MASK
5
24
ROW3
OSC OUT
6
23
ROW2
OSC IN
7
22
ROW1
FILT IN
8
21
COL3
FILT OUT
9
20
COL2
HSW
10
19
COL1
11
18
MUTE
12
17
MFOUT
PAUSE OUT
13
16
COL7
ROW5
14
15
ROW6
V
V
SS
DD
DR-00684
Package:
DIP28
1/14
4120
PDS039-SA589-001
REV. C
09-03-1995
SA589 FAMILY
TABLE 1:
PIN FUNCTIONS
Pin
number
1
3
4
5
Pin
name
NC
IMP
SELECT
MASK
6
7
8
9
10
OSC OUT
OSC IN
FILT IN
FILT OUT
HSW
Hook'
VSS
VDD
PAUSE OUT
MF OUT
MUTE
COL1
COL2
COL3
COL4
COL5
COL6
COL7
ROW1
ROW2
ROW3
ROW4
ROW 5
ROW 6
ROW 7
11
12
13
17
18
19
20
21
26
27
2
16
22
23
24
25
14
15
28
1.
2.
Function
Not connected
'Loop disconnect' dialling output
LD/DTMF selection, IDP and B/M ratio programming
Output to disable speech circuit during pulse dialling and recall
(see note 1)
Connections for 560kHz ceramic resonator
Unity gain amplifier input and output for DTMF tone filtering
Hookswitch input - a logic 1 at this pin is used to indicate 'OffNegative supply
Positive supply
Active high indicating a pause when dialling from memory
Unfiltered DTMF output
Output active during keying and tone transmission (see note 2)
Connections for 38 key single contact keypad
MASK may be used to disconnect the whole speech circuit in order to maintain the break
condition whilst on-hook and during a TBR (Timed Flash) operation.
MUTE is provided to disable the microphone while maintaining the loop during DTMF
transmission.
OPERATION
Power-on
When power is applied to the chip, a power-on reset circuit operates and ensures that the
Memories are cleared and all logic is reset. The power-on reset circuit is designed such that
if the chip supply voltage drops to a level at which the memories may be corrupted, it will
always, under all conditions, clear the memory, so that corrupt data is not retained.
2/14
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SA589 FAMILY
Hookswitch Operation
The HSW input is used to inform the SA589 of whether the telephone is on or off hook. Logic
'0' is recognised as on-hook. Logic '1' is recognised as off-hook. When the HSW input rises
from '0' to '1' the off-hook state is recognised immediately and keypad inputs are accepted.
However, when the HSW input falls from '1' to '0' the on-hook state is not recognised for 200
- 300ms. This is so that short line breaks of less than 200ms, such as the line reversals applied
by the exchange, are ignored. In this case the IMP and MASK outputs will go low immediately
the HSW input goes low in order to preserve current, but will resume normal operation
immediately HSW goes high.
On-hook state
In the on-hook state all chip outputs are set low, the oscillator circuit is inhibited and no key
inputs are accepted. This conserves supply current so that the MEMORY contents may be
retained.
Off-hook state
When the HSW input goes high, the MASK output immediately goes to the logic '1' level and
remains there until going on-hook or signalling a TBR, (see timing diagram). COLUMN
outputs also go high until a key is pressed and are normally off whenever timing functions are
not required.
Keypad Operation
A Single Contact, Normally Open keypad is required. When off-hook the COLUMN outputs
are normally held high and the ROW inputs are low. When a key is pressed this connects a
COLUMN output to a ROW input and the ROW input is pulled high.
This action initiates keyboard scanning. During keyboard scanning, the COLUMN outputs
are normally low but generate scanning pulses at 7ms intervals on each output in sequence.
A key is accepted as valid when two successive scanning pulses from the same COLUMN are
seen on a ROW input. Hence, the minimum bounce-free key closure period which is
necessary to guarantee detection is about 14ms (plus the oscillator start-up time if it was not
already running).
Simultaneous key depressions
If two keys are pressed simultaneously (i.e. a second key is pressed before the first has been
verified) neither key will be accepted until both keys are released and the correct key is pressed
again.
Dialling Mode Selection
The dialling mode may be selected via the SELECT pin (Pin 4) as detailed in Table 2. Four
'Loop-Disconnect' + DTMF options, two 'Loop-disconnect only' options and three DTMF
modes are available. Each mode offers a different combination of LD and/or MF timing. If
one of the 'LD only' or DTMF only modes is selected then dialling will remain fixed in LD mode
or DTMF mode respectively.
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3/14
SA589 FAMILY
COL
1
COL
2
COL
3
COL
4
COL
5
COL
6
COL
7
ROW 1
1
2
3
TBR
S01
S02
S03
ROW2
4
5
6
REDIAL
S04
S05
S06
ROW3
7
8
9
STORE
S07
S08
S09
ROW4
*
0
#
PAUSE/
CONT
SHIFT
S00
LNR
S11
S12
S13
S14
S15
S16
S17
S18
S19
ROW5
ROW6
S10
ROW7
Fig. 2a Versions without TONE key
* or */# are used to change from LD to DTMF dialling and are available as digits when in DTMF
mode.
TBR: Timed Break Recall (Flash).
STORE: Memory Programming key. Use in conjunction with dedicated memory keys or a
two-digit code representing the number of the memory to be programmed
S00-S19: 'Single touch' dedicated memory dialling keys
LNR: Last Number Redial
REDIAL and SHIFT: These keys are clearly unnecessary where keypad positions are
provided for all the dedicated memory keys but may be useful to access memories in
applications where the telephone provides insufficient keys for all these functions. For a
description of the function of the REDIALand SHIFT keys, see the SA585 and SA587 data
sheets, respectively. Do not fir keys in these positions if not required.
PAUSE/CONT: Insert pause in memory/continue dialling
TONE: Change dialling mode from LD to DTMF
COL
1
COL
2
COL
3
COL
4
COL
5
COL
6
COL
7
ROW 1
1
2
3
TBR
S01
S02
S03
ROW2
4
5
6
REDIAL
S04
S05
S06
ROW3
7
8
9
STORE
S07
S08
S09
ROW4
*
0
#
TONE
SHIFT
S00
LNR
S11
S12
S13
S14
S15
S16
S17
S18
S19
ROW5
ROW6
S10
ROW7
Fig. 2b Versions with TONE key
Fig. 2 Keypad layout and connections
4/14
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SA589 FAMILY
TABLE 2: Dialling mode selection
Select Pin to
VSS
Dialling Mode
LD + DTMF
B:M Ratio
2:1
TBR (msec)
100
COL1
LD + DTMF
2:1
270
COL2
LD + DTMF
3:2
270
COL3
LD + DTMF
3:2
100
COL4
LD only
2:1
-
COL5
DTMF only
-
270
COL6
DTMF only
-
270
COL7
LD only
3:2
-
VDD
DTMF only
-
100
However, if one of the 'LD + DTMF' modes is selected the chip will be in LD mode initially in
the off-hook condition but may be switched to DTMF by pressing either *, */# or TONE key
(depending on the mask variant - see Fig. 2 and page 11), provided that dialling is not in
progress. If any of these keys are pressed during LD dialling, they will be ignored.
Only if * or # are pressed subsequent to switching to DTMF, will * or # be dialled. Only digits
entered prior to a switch to DTMF will subsequently be available for redialling (see Last
Number Redial operation), unless specified otherwise.
Once switched to DTMF, dialling will remain in this mode until either a Recall (Flash) operation
or until the chip returns to the on-hook state.
Last Number Redial (LNR)
The function of the on-chip LNR store is to retain automatically a manually dialled number for
redialling later. The capacity of the memory is 24 digits. If a number is dialled which is longer
than this, dialling will continue, but redialling will not be allowed with this number. To redial
a number in the LNR store, the LNR key may be pressed once, or the Redial key can be
pressed twice.
The last number redial store has several features designed to assist the user:
Moving cursor facility
This facility is provided to aid use in PABX applications, where the user must first dial an
access digit, or digits, and then wait for a second dial tone before continuing dialling.
This allows a user to enter the first digit or digits of the number in the last number redial store
manually before pressing the LNR key; the remainder of the number will be dialled when
the LNR key is pressed.
If the digit(s) dialled manually do not match those in the LNR memory, then redialling will
be inhibited for the remainder of the call, and the numbers entered will be saved in the LNR
memory for redialling in a subsequent call.
If the user manually dials the first digit(s) in the LNR memory, and then goes on-hook, the
whole contents of the memory will be retained.
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5/14
SA589 FAMILY
Mixed Mode Calls
In the case of a call which starts in LD mode and is switched by the user (via the *, */#, or
TONE key) to DTMF mode, only the digits dialled in LD mode will be retained. This feature
is provided to ensure security of PIN (Personal Identification Number) codes. Provided that
the number of digits dialled in LD mode does not exceed 24, they will be retained regardless
of the number of DTMF digits entered subsequently.
Memory Dialling
The SA589 provides 20 memories, each of which has a capacity of 24 digits and each of which
has its own dedicated key . The memories can save digits for dialling in LD, DTMF and Mixed
Modes and can include pauses if desired.
Programming Memories
The SA589 must be 'off-hook' and idle:
1.
Press the STORE key.
2.
Press the key (S00 - S19) of the memory to be programmed.
3.
Enter digits to be stored (no digits will be dialled whilst programming).
4.
To finish programming the memory either press the STORE key again or go 'on-hook'.
5.
Repeat to programme other memories.
If more than 24 digits are entered while programming a memory, then the memory will be
cleared until reprogrammed. If any non-valid keys are pressed during programming
(e.g.LNR, TBR) they will be ignored.
Mixed mode numbers and Pauses in memory
Mixed mode (i.e. LD + DTMF) numbers are easily programmed into memory. The SELECT
pin should be set to one of the 'LD + DTMF' modes (as it would be when dialling a mixed
mode number), then the number entered using the same procedure as if dialling normally.
The first press of *, */# or TONE (according to the mask variant) will be stored as a 'change
to DTMF' and this will cause all subsequent digits to be sent in DTMF when redialling from
memory.
Similarly, pauses can be stored in memory by pressing the PAUSE key in the appropriate
position when programming.
When redialling from memory, both Pauses and LD to DTMF changeovers will cause dialling
to halt temporarily until the user presses the PAUSE/CONT key. The exception to this rule
is when an LD to DTMF changeover, is stored in the first memory location; in this case,
DTMF dialling will occur immediately when memory dialling is invoked - this allows DTMF
codes to be easily stored and sent even in a telephone where the normal dialling mode is
LD.
It should be noted that a Pause or an LD to DTMF changeover each require one memory
location.
6/14
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SA589 FAMILY
Dialling from memories
The SA589 must be 'off-hook' and idle:
1.
Press the appropriate memory key (S00 - S19). Dialling will now start.
2.
If dialling halts due to a Pause or an LD to DTMF changeover in the memory, the PAUSE
OUT pin will go high (logic '1'). Further dialling can be resumed by pressing the PAUSE/
CONT key or alternatively, by pulling the Column 4 pin low (for a minimum of 14 ms)
to achieve the same result thus allowing an external timer circuit to be used. The
PAUSE OUT output is reset when dialling resumes.
All keypad positions are disabled whilst memory dialling is in progress.
Timed Break & Earth Loop Recall
The SA589 supports both TBR and ELR and offers a common operating protocol in both
cases.
After a recall (Flash) operation, the dialling mode selected via the SELECT pin will be restored.
Also, only the digits dialled after the ELR/TBR operation will be retained in the LNR store (1).
A TBR (Flash) of 100ms or 270ms(2) is generated when the TBR key is pressed. The MASK
output goes low in order to produce the line break. When in DTMF mode, the MF OUT output
also goes low for the duration of the break.
ELR is supported via the column 3 pin. If this pin is connected to ground for a minimum of 20ms
during an ELR operation, the chip will offer the same operating protocol as for TBR.
This may be achieved by use of the circuit shown below in Fig. 3, or by use of a double contact
switch.
(1)
(2)
Other options are available.
Other TBR (Flash) periods are available as mask options
SA589
21
COL 3
22
DR-00685
Fig. 3 Earth loop recall
sames
7/14
SA589 FAMILY
Oscillator Circuit
This requires an external 560kHz ceramic resonator connected between OSC IN and OSC
OUT to provide a timing reference for all chip functions. No other components are required
or should be used.
The oscillator circuit is of the 'single pin' type. Internally, the OSC IN pin is connected to VSS
and therefore the resonator may alternatively be connected externally between OSC OUT and
VSS if desired.
Please consult your resonator supplier who will recommend a suitable resonator type.
Tone Filtering
The spectral purity of the DTMF output is sufficient for most applications. However, where
lower distortion DTMF tones are required, an on-chip darlington pair is provided (accessible
via pins 7 & 8) for use in a low pass active filter.
Fig. 4 shows how a 2-pole Sallen and Key filter can be implemented. The typical component
values have been chosen to give a second order Butterworth response with a cut-off frequency
of about 3,5kHz and a nominal pass-band insertion loss of 0.5dB.
DTMF DIALLING
During DTMF dialling the MUTE output goes to logic '1' and remains there for the duration of
the tone transmission.
The IMP output remains low during tone transmission. The MF OUT output rises to its DC level
of 0.9 VDD at the start of the tone transmission and is kept there between tone bursts. This is
to avoid transients at the beginning and end of tone bursts.
The maximum rate at which tones are sent to line is 100ms on, followed by 100ms off (unless
specified otherwise). If keys are activated faster than this they are placed in a temporary store
and then sent to line at the maximum rate. Dialling from the LNR memory occurs at the
maximum rate.
If a key is held down for longer than the minimum Tone Burst period, the tone output will
continue until the key is released.
8/14
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SA589 FAMILY
SA589
V
DD
17
8
9
FILTOUT
FILTIN
MFOUT
R2
C1
R3
R1
C12
OUTPUT
R4
Typical values:
R1
= 56k Ω
R2
= 56k Ω
R4 + R3 = 10k Ω
C1
= 1.3nF
C2
= 470pF
V
SS
DR-00686
Fig. 4 DTMF tone filtering
HOOK SWITCH
KEY PRESS
COLUMN
ROW
"8"
"5"
"TBR"
"9"
MASK
IMP(LOW)
100ms
MUTE
"5"
"8"
"9"SHORTENED
MF OUT
100ms
100ms
ON HOOK
TIME OUT
DR-00687
Fig. 5 DTMF mode timing diagram
sames
9/14
SA589 FAMILY
TABLE 3: Tone Frequencies
Keypad
R1
R2
R3
R4
C1
C2
C3
C4
Nominal frequency (Hz)
697
770
852
941
1209
1336
1477
1633
Deviation from nominal (%)
-0.07
-0.10 +0.19 -0.15 -0.17
-0.20
-0.22
-0.31
NOTE: There will be an additional frequency error caused by any deviation of the resonator
frequency from the nominal 560kHz.
LOOP DISCONNECT DIALLING
The MASK output is provided in order to disable the speech circuit during LD dialling.
Consequently the MASK output is normally at logic '1' in the off-hook condition, but changes
to logic '0' during LD dialling. MASK also changes to logic '0' in order to signal a Timed Break
Recall (Flash) to the line.
Both MUTE and MF OUT remain low during LD dialling. LD dialling is signalled on the IMP
output. A break is signalled by a logic '0'. Make periods and IDP times are signalled by a logic
'1'. When not dialling, the IMP output sits at logic '0'.
HOOK SWITCH
KEY PRESS
COLUMN
ROW
"5"
"TBR"
"8"
"9"
MASK
IMP
"5"
"IDP"
"8"
"9"
(PARTIAL)
2 . 2 3 4 0
MUTE(LOW)
MF OUT
ON HOOK TIME OUT
DR-00688
Fig. 6 LD mode timing diagram
10/14
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SA589 FAMILY
IMP
t5
t1
t2
t4
t3
t3
t1
=
PRE-DIGIT PAUSE (=t
)
5
t2
=
BREAK PERIOD (60ms or 67ms)
t3
=
MAKE PERIOD (40ms or 33ms)
t4
=
POST-DIGIT MAKE (=t
t5
=
INTER-DIGIT PAUSE (800ms)
)
3
DR-00689
Fig.7 Timing data
MASK OPTIONS
The SA589 has been designed so that many features can be altered quickly and inexpensively
at the final stage of manufacture. These options allow the telephone manufacturer to cater
for different market requirements throughout the world without changing the telephone circuit.
The options, listed below, are possible in any combination. Standard options are listed first
in bold italics at 'a'. Other options may be produced by arrangement. Please consult your
nearest SAMES Representative for advice on availability.
A.
B.
'Long' TBR (Flash) Period
a. 270ms
b. 600ms
LD to DTMF Keypad Switching
a. * and # keys
b. TONE key
c. * key
C.
Retention of Post-*/#Digits in LNR Store (DTMF Mode)
a. All digits retained
b. Digits before * or # retained
D.
Short/Long TBR Selection
a. As specified
b. Short and Long TBR reversed
E.
Recall (Flash)/LNR protocol
a. Digits dialled after Recall retained
b. Digits dialled before Recall retained
sames
11/14
SA589 FAMILY
F.
DTMF Minimum Timings
a. 100ms on, 100ms off
b. 85ms on, 85ms off
c. 85ms on, 170ms off
G.
Pin 5
a. MASK
b. MASK
H.
Pin 3
a. IMP
b. IMP
c. [IMP + MASK]
d.
[IMP + MASK]
I.
Pin 18
a. MUTE
b. MUTE
J.
Pin 13 Function
a. PAUSE OUT
b. SECRECY
ABSOLUTE MAXIMUM RATINGS *
Parameter
Min
-0,3
Supply Voltage VDD - VSS
Voltage on any pin (except HSW)
VSS -0,3
Voltage on pin HSW
VSS -0,3
Current at any pin
-1
(except HSW, FILTOUT and FILTIN)
Current at pin FILTOUT
0
Current at pin FILTIN
-5
Operating Temperature
-25
Storage Temperature
-55
Typ
Max
Unit
6,5
V
VDD +0,3
V
V
1
mA
0,1
0
70
125
Notes
See Note 1
mA
mA
°C
°C
* Stresses above those listed under "Absolute Maximum Ratings" may cause permanent
damage to the device. This a stress rating only. Functional operation of the device at these
or any other condition above those indicated in the operation sections of this specification, is
not implied. Exposure to Absolute Maximum Ratings for extended periods may affect device
reliability.
Note 1: A diode is internally connected between this pin and VDD . Provided current is externally
limited to 300µA max, no damage will occur.
12/14
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SA589 FAMILY
DC ELECTRICAL CHARACTERISTICS
(VDD = 2,5V at 25°C, unless otherwise specified)
Condition
Supply voltage:
Min
1,8
2,4
Typ
Max
5,7
V
Unit
V
Notes
on-hook
For memory retention
off-hook
5,7
Hookswitch input: on-hook
0,2 VDD
off-hook
0,8 VDD
Supply Current: on-hook
<0.2
5
µA VDD = 2.5V (See note 1)
off-hook
1,5
µA
See note 1
MF tone sending
1,0
mA
If MF OUT is low
LD impulsing
200
µA
Output High Voltage
2,2
V
I = -1mA
(MASK, MUTE and IMP Outputs)
Output Low Voltage
0,3
V
I = +1mA
(MASK, MUTE and IMP Outputs)
MF OUT d.c. Level During Tone
V
Sending
0,9V DD
MF OUT Output Resistance
3
KΩ
'Key Pressed' Resistance
2
KΩ
2,5V<VDD <5,7V
'Key Not Pressed' Resistance
500
KΩ
2,5V<VDD <5,7V
Darlington Pair Current Gain
600 50,000
Ie=100µA,Vce=2V
NOTE 1:
Specially tested versions with guaranteed lower on-hook supply current are
available
AC ELECTRICAL CHARACTERISTICS
(VDD = 2,5V at 25°C, unless otherwise specified)
Condition
Oscillating Frequency
Tone Output: Low Group
High Group
High-to-Low Group Amplitude Ratio
Total harmonic Distortion: 0-4KHz
0-10KHz
0-50KHz
0-200KHz
sames
Min
68
1,5
Typ
560
77
97
2
1,5
2,5
5,0
6,5
Max
Unit
kHz
mVrms
109 mVrms
2,5
dB
%
%
%
10
%
Notes
No Load
No Load
at MF OUT
13/14
SA589 FAMILY
Disclaimer: The information contained in this document is confidential and proprietary to South African MicroElectronic Systems (Pty) Ltd ("SAMES) and may not be copied or disclosed to a third party, in whole or in part,
without the express written consent of SAMES. The information contained herein is current as of the date of
publication; however, delivery of this document shall not under any circumstances create any implication that
the information contained herein is correct as of any time subsequent to such date. SAMES does not undertake
to inform any recipient of this document of any changes in the information contained herein, and SAMES
expressly reserves the right to make changes in such information, without notification,even if such changes would
render information contained herein inaccurate or incomplete. SAMES makes no representation or warranty that
any circuit designed by reference to the information contained herein, will function without errors and as intended
by the designer.
South African Micro-Electronic Systems (Pty) Ltd
P O Box 15888,
33 Eland Street,
Lynn East, 0039
Koedoespoort Industrial Area,
Republic of South Africa,
Pretoria,
Republic of South Africa
Tel:
Fax:
14/14
012 333-6021
012 333-8071
Tel:
Fax:
sames
Int +27 12 333-6021
Int +27 12 333-8071