Overview
The LC737212 and LC737212M are CMOS LSI
telephone dialers for pushbutton telephones. They support
both DTMF and pulse dialing. These products include 25
16-digit memories for storing telephone numbers and one
63-digit memory for redialing, and they provide, in a
single chip, all the functions required for dialing and
control for a standard independent telephone, including
on-hook dialing and a hold function. They also provide a
serial I/O interface for connection to a microcontroller.
Functions
• Fabrication in a CMOS process that allows these circuits
to be directly operated from a telephone line
• Support for single-contact keypads
• Built-in oscillator circuit (fosc = 3.58 MHz) that can
drive either a standard color-TV crystal oscillator
element or a ceramic resonator
• High-precision DTMF signal
• Frequency generator circuit (±0.1%) adopted for eased
ceramic resonator selection
• Five one-touch 16-digit auto-dial memories and 20
quick-dialing memories
• On-hook or off-hook can be specified for memory
entries.
• Mode change and pause data items can be stored in the
dialing memories.
• 63-digit redial memory
• Automatic pause (3.9 seconds) insertion when the mode
is switched.
• Automatic pause (1.0 second) insertion after a flash
operation.
• Mode changing is one-directional, from pulse mode to
tone mode.
• Output of a key press tone (1036 Hz, 31 ms) for keys
other than DTMF keys when key input is valid
• Output of an operation complete confirmation tone
(2072 Hz, 279 ms for each telephone number) when a
telephone number is stored in memory
• Generates 12 signal types in DTMF mode.
• Supports an on-hook dialing mode.
• Supports a hold function with hold mode.
• Supports both 10 and 20 pps dialing pulse rates.
• The mode can be switched from either the P/T pin or by
a key input.
• Settable dialing pulse circuit closed ratio (make
percent): either 33% or 39%.
• Supports either keypad or serial input.
• Provides serial output of the keypad input data and the
internal status.
• Capable of controlling the serial output timing.
• Supports 18 user-defined keys.
• Wide operating power-supply voltage range
— Pulse mode: V
DD
= 1.5 to 5.5 V
— DTMF mode: V
DD
= 2.0 to 5.5 V
• Low power operation
— Pulse mode: I
DD
= 0.5 mA max (V
DD
= 3.0 V)
— DTMF mode: I
DD
= 1.0 mA max (V
DD
= 3.0 V)
• Low standby current
— I
DR
= 0.5 µA max (V
DD
= 1.0 V)
Ordering number : EN5203
203
21398RM(OT) No. 5203-1/27
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN
Package Dimensions
unit: mm
unit: mm
3170-DIP36S
3129-MFP36SD
No. 5203-2/27
LC737212, 737212M
SANYO: DIP36S
[LC737212]
SANYO: MFP36SD
[LC737212M]
Specifications
Absolute Maximum Ratings
at Ta = 25°C
Allowable Operating Ranges
at Ta = 25°C
Parameter
Symbol
Conditions
Ratings
Unit
Maximum power supply voltage
V
DD
max
–0.3 to +6.5
V
Maximum input voltage
V
IN
max
–0.3 to V
DD
+0.3
V
Maximum output voltage
V
OUT
max
–0.3 to V
DD
+0.3
V
Allowable power dissipation
Pd max
Ta
≤
70 ˚C
250
mW
Minimum load resistance
P
L
min
Between the DTMF and V
SS
pins
1
k
Ω
Operating temperature
Topr
–30 to +70
°C
Storage temperature
Tstg
–40 to +125
°C
Parameter
Symbol
Conditions
min
typ
max
Unit
Supply voltage
V
DDP
Pulse mode
1.5
5.5
V
V
DDT
DTMF mode
2.0
5.5
V
Input high-level voltage
V
IH
All input pins
0.7 V
DD
V
DD
V
Input low-level voltage
V
IL
All input pins
V
SS
0.3 V
DD
V
Key contact resistance
R
KI
3.0
k
Ω
Keypad capacitance
C
KI
330
pF
Oscillator element rating
f
Center frequency = 3.579545 MHz
–1.3
+1.3
%
R
S
100
Ω
Electrical Characteristics
at Ta = 25°C, fosc = 3.579545 MHz
AC Characteristics
at Ta = 25°C, fosc = 3.579545 MHz
No. 5203-3/27
LC737212, 737212M
Parameter
Symbol
Conditions
min
typ
max
Unit
Operating current drain
I
DDP
Pulse output mode, outputs open, V
DD
= 3.0 V
0.3
0.5
mA
I
DDT
DTMF output mode,outputs open, V
DD
= 3.0 V
0.5
1
mA
Static current drain
I
DD(ST)
Standby mode, outputs open, V
DD
= 1.5 to 5.5 V
1
µA
Memory retention voltage
V
DR
Between V
DD
and V
SS
1
V
Memory retention current
I
DR
V
DD
= 1 V
0.5
µA
The SOUT-ENA, OFF-HOOK, DPR, P/T, BMR,
I
IH1
ON-HOOK-DIAL IN, HOLD-OFF IN, DISCON IN,
1
µA
Input pin current
SI/KEY, OFF/ON-HOOK, and STORE pins, V
IH
= V
DD
The SOUT-ENA, OFF-HOOK, DPR, P/T, BMR,
I
IL1
ON-HOOK-DIAL IN, HOLD-OFF IN, DISCON IN,
–1
µA
SI/KEY, OFF/ON-HOOK, and STORE pins, V
IL
= V
SS
I
ILK1
All key pins, V
DD
= 1.5 V, V
ILK
= V
SS
–20
µA
I
ILK2
All key pins, V
DD
= 5.5 V, V
ILK
= V
SS
–300
µA
Key pin current
I
OLK1
All key pins, V
DD
= 1.5 V, V
OLK
= 0.4 V
200
µA
I
OLK2
All key pins, V
DD
= 5.5 V, V
OLK
= 0.4 V
0.7
mA
Output pin leakage current
I
OFF
V
O
= V
DD
, V
DD
= 5.5 V, with the output off, the DP,
1
µA
MUTE1, MUTE2, and S-OUT pins.
V
OH1
The K-TONE, HOLD-OUT, HOOK-CTL,
V
DD
– 0.5
V
and SP-CTL pins, V
DD
= 1.5 V, I
OH
= –250 µA
V
OH2
The K-TONE, HOLD-OUT, HOOK-CTL,
V
DD
– 1
V
Output pin voltage
and SP-CTL pins, V
DD
= 5.5 V, I
OH
= –1 mA
V
OL1
The K-TONE, DP, MUTE1, MUTE2, SP-CTL,
0.4
V
HOLD-OUT, and HOOK-CTL pins, V
DD
= 1.5 V, I
OL
= 250 µA
V
OL2
The K-TONE, DP, MUTE1, MUTE2, SP-CTL,
0.4
V
HOLD-OUT, and HOOK-CTL pins, V
DD
= 5.5 V, I
OL
= 1 mA
Parameter
Symbol
Conditions
min
typ
max
Unit
Key debounce time
T
KD
30
ms
Pin chatter exclusion time
T
PCHT
OFF-HOOK, P/T, ON-HOOK-DIAL, IN HOLD OFF IN
45
ms
Key scan frequency
f
KSC
258.9
HZ
Key tone frequency
f
KT
1035.7
HZ
Key tone output time
T
KT
30.9
ms
In Pulse mode at 10 pps
3.88
3.9
3.93
s
Auto-pause time
T
AP
In Pulse mode at 20 pps
3.88
3.9
3.93
s
DTMF mode
3.88
3.9
3.93
s
DTMF output time
T
MFON
98
100
102
ms
DTMF interdigit pause time
T
MFOFF
93
95
97
ms
Hooking time
T
HK
700
710
720
ms
Hooking pause time
T
HKP
0.98
1.0
1.02
s
Memory store confirmation
f
KST
2071.4
Hz
tone frequency
Memory store confirmation
T
KSTON
278.1
ms
tone output time
Low tone amplitude
V
OR
V
DD
= 3.5 V, R
L
= 10 k
Ω
165
200
240
mVrms
Tone output ratio
dBCR
V
DD
= 2.0 to 5.5 V, R
L
= 10 k
Ω
1
2
3
dB
Tone output distortion
DIS
V
DD
= 2.0 to 5.5 V, R
L
= 10 k
Ω
10
%
Oscillator start time
T
START
V
DD
= 1.5 to 5.5 V
30
ms
V
DD
= 3.0V
1
ms
Pulse Dialing Output
/fosc = 3.579545 MHz
DTMF Output
/fosc = 3.579545 MHz
Pin Assignment
No. 5203-4/27
LC737212, 737212M
Dialing
Interdigit
Make
DPR pin
BMR pin
pulse rate
pause
percent
V
SS
V
DD
9.94 pps
834.2 ms
33.2%
V
DD
V
DD
19.89 pps
525.2 ms
33.2%
V
SS
V
SS
9.94 pps
834.2 ms
39.2%
V
DD
V
SS
19.89 pps
525.2 ms
39.2%
Input
Output frequency [Hz]
Deviation [%]
Standard
LC737212
R1
697
697.0
+0.01
R2
770
770.1
–0.02
R3
852
852.3
–0.03
R4
941
942.0
–0.11
C1
1209
1209.3
–0.03
C2
1336
1335.7
+0.03
C3
1477
1476.7
+0.02
C4
1633
1633.0
+0.00
Top view
Block Diagram
No. 5203-5/27
LC737212, 737212M
Keypad Layout
Key Matrix Functions
(when the SOUT-ENA pin is high)
Digits 1 to 9, 0:
Dialing data
* and #:
DTMF dialing data
In pulse mode, the * key switches the LC737212/M to DTMF mode.
F:
Flash (0.71 second)
M:
Quick-dialing address specification (only in the on-hook state, sets up memory store mode)
R/P:
Redial, pause (3.9 seconds), clear the paused state
HOLD ON/OFF:
Controls the on/off state of hold mode
STORE:
Sets up memory store mode.
A1 to A5:
One-touch dialing key
00 to 17:
Definable function keys
The keypad is formed as a matrix using the key input pins (R1 to R5 and C1 to C8) and supports 40 keys. A given key is
input by shorting or grounding the column pin and the row pin for that key. To prevent discharge of the backup battery
due to inadvertent key presses in standby mode (when the circuit is disconnected from the telephone line), key input by
shorting is not accepted. This means that if on-hook storing of telephone numbers in memory is selected, the application
must implement STORE key (or M key) input by grounding the ROW pin and COLUMN pin.
• Digit keys (1 to 9 and 0)
— Dialing data keys
— Quick-dialing memory address specification keys
• * and # keys
— DTMF mode:
The * and # keys function as dial data keys
— Pulse mode:
* ... Pulse/tone switching key
# ... Unused.
• F key (flash key)
Invokes an operation equivalent to 0.71-second hooking implemented by turning on the DP output for 0.71 second.
Although a 1-second pause is automatically inserted, the following dialing data may be entered during that period.
Redialing is possible after a flash operation.
• M key (memory key)
When on-hook memory registration is set up, the system switches from standby mode to memory registration mode
when the M key is pressed. The address of the dialing memory is specified by combination of the digit keys that are
pressed immediately after the M key. The system operates as follows when the memory address operation is performed
incorrectly.
No. 5203-6/27
LC737212, 737212M
1
2
3
F
00
05
10
15
4
5
6
M
01
06
11
16
7
8
9
R/P
02
07
12
17
*
0
#
HOLD
03
08
13
A4
ON/OFF
A1
A2
A3
STORE
04
09
14
A5
R1
to
R5
C1
to
C8
Memory readout
Memory store
• R/P key
After connecting to the line, the R/P functions as a redial key as long as the system has not performed a dialing output
operation. In manual dialing mode, the R/P key functions as the pause data key.
When dialing from memory:
— During a pause operation:
Cancels the pause
— While dialing:
Inserts a pause
During a redial operation:
— During a pause operation:
Cancels the pause
— While dialing:
Ignored
If two or more pause characters occur in the data, the pause cancel operation will cancel all pending pauses in a single
operation.
• STORE key
Pressing the STORE key sets the system to memory store mode. Pressing the STORE key again during a memory store
operation cancels all input data.
• HOLD ON/OFF key
Controls the on/off state of off-hook mode. No key tone is output at this time.
• Keys A1 to A5
These are the one-touch auto-dialing keys. Pressing one of these keys outputs the corresponding memory data from the
DP and DTMF pins.
• Keys 00 to 17
These are user-defined keys. When one of these keys is pressed, the LC737212/M outputs the corresponding status and
key code from the serial interface.
No. 5203-7/27
LC737212, 737212M
No. 5203-8/27
LC737212, 737212M
Pin Functions
Pin No.
Symbol
Function
1
C5
Column input
2
R1
3
R2
4
R3
Row input
5
R4
6
R5
7
SOUT-ENA
Serial output enable, H: enable, L: disable
8
HOLD-OFF IN
Hold mode clear input; falling edge detection.
9
ON-HOOK DIAL IN
On-hook dialing input; falling edge detection
10
SI/KEY
Serial input/keypad input switching
11
ON-HOOK
Hook-switching input
12
DPR
Dialing pulse rate switching; H: 20 pps, L: 10 pps
13
R/T
Pulse/tone switching; H:pulse, L: tone
14
BMR
Make percentage switching input; H: 33%, L: 39%
15
XIN
Oscillator circuit. Connect either a crystal or ceramic oscillator element with a
16
XOUT
frequency of 3.58 MHz between these pins.
17
OFF/ON-HOOK STORE
Off-hook store/on-hook store switching
18
V
DD
Power supply
19
V
SS
20
SP-CTL
Speaker reception control output; complementary output
21
DTMF
DTMF output; npn emitter-follower output
22
MUTE2
DTMF mute output; n-channel open drain output
23
MUTE1
DP and K-TONE muting output; n-channel open drain output
24
S-OUT
Serial data output; n-channel open drain output
25
DP
Dialing pulse output; n-channel open drain output
26
K-TONE
K-tone output; complementary output
27
HOOK-CTL
Hook control output; complementary output
28
HOLD-OUT
Hold mode output; complementary output
29
DISCON IN
Disconnect input
30
C1
31
C6
32
C7
33
C2
Column inputs
34
C8
35
C3
36
C4
• 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.
We recommend setting the DISCON pin low when power is first applied, and setting it high after the power-supply
voltage (V
DD
) has reached or exceeded 1.5 volts.
• 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
LC737212, 737212M
Off-hook input
On-hook Dial input
Status
H
H
STANDBY
H
L
ON-HOOK DIAL
L
H
OFF-HOOK DIAL
L
L
MONITOR
1 to 10 k
Ω
0.1 to 10 µF
• SP-CTL
This pin provides the speaker reception control output. This output is set on during the on-hook dialing, monitor, and
hold states. This is a complementary output.
• DTMF
The DTMF output pin. This is an npn emitter-follower output.
• MUTE2
The DTMF muting output. This output is turned on in synchronization with the DTMF output. This is an n-channel
open-drain output. The wired OR with the MUTE1 output can be taken.
• MUTE1
The DP and K-TONE muting output. This output is turned on in synchronization with the dialing pulse and K-TONE
outputs. This is an n-channel open-drain output. The wired OR with the MUTE2 output can be taken.
• S-OUT
The serial data output. This pin is used to output the internal status of the LC737212/M and the keypad data. This is an
n-channel open-drain output.
• DP
The dialing pulse output. This is an n-channel open-drain output.
• K-TONE
This pin outputs the key input confirmation tone (1036 Hz, 31 ms) and the memory store confirmation tone (2073 Hz,
279 ms). This is a complementary output.
• HOOK-CTL
The circuit control output. A high level is output when the circuit is connected. This is a complementary output.
• HOLD-OUT
The hold control output. A high level is output during a hold. This is a complementary output.
• XIN and XOUT
The oscillator connection pins. Connect a 3.579545-MHz oscillator element. No other external components are
required if a crystal oscillator element with built-in feedback resistor and capacitor components is used. Two 30-pF
capacitors are required if a ceramic resonator is used.
• R1 to R5 and C1 to C8
The keypad connections.
• V
DD
and V
SS
The power supply connections.
No. 5203-10/27
LC737212, 737212M
No. 5203-11/27
LC737212, 737212M
Pin Internal Circuit
Pin No.
Pin
Internal equivalent circuit
1 to 6
30 to 36
R1 to R5
C1 to C8
7 to 14
17
29
SOUT-ENA
HOLDOFF IN
ON-HOOKDIAL IN
SI/KEY
OFF-HOOK
DPR
P/T
BMR
OF/ON-HOOK STORE
DISCON IN
15
X
IN
16
X
OUT
22 to 25
MUTE2
MUTE1
S-OUT
DP
20
26 to 28
SP-CTL
K-TINE
HOOK-CTL
HOLD-OUT
21
DTMF
Key Operations
↓
: On hook
↑
: Off hook
: Key input
Dn: Pulse output
Dn: Tone output
Timing Charts
Pulse dialing
Item
Key Input
Dialing Output
↑
,
• • • • •
Dn
D
2
D
1
↑
,
• • • • •
Dn
D
2
D
1
Normal dialing and redialing (pulse mode)
Normal dialing using the key (pulse mode)
No. 5203-12/27
Dn
R/P
Normal dialing (pulse mode)
Normal dialing including mode changes
(pulse mode at the start of the operation)
Memory store and
readout
Quick dialing
One-touch dialing
Normal
Redialing
Using keys
Using the P/T
switch
Store (pulse mode)
Readout
Store (tone mode)
Readout
D
1
, D
2
• • • • •
Dn
D
1
, D
2
D3
D
1
, D
2
• • • • •
Dn
D
1
, D
2
• • • • •
Dn
D
1
, , D
2
, D
3
D
1
, D
2
, D
3
D
1
, D
2
, D
3
3.9 s
3.9 s
.
.
.
.
.
D
1
, , D
2
, D
3
3.9 s
.
.
↑
,
,
,
D
3
R/P
D
2
D
1
↓
↑
R/P
↑
,
,
,
D
3
D
2
*
D
1
↑
,
(P/T
↓
)
,
,
D
3
D
2
D
1
↓
D
5
D
4
M
D
3
D
2
D
1
STO
↑
D
5
D
4
M
↓
A
1
D
3
D
2
D
1
STO
↑
A1
LC737212, 737212M
.
DTMF dialing
Flash operation
Pulse/tone mixed dialing
After the pulse dialing (including IDP) has completed, when DTMF key input operations are performed, DTMF signals are output continuously while keys are
pressed.
No. 5203-13/27
LC737212, 737212M
Pulse/Tone Mixed Dialing (using automatic pausing)
If a DTMF key operation is performed during dialing pulse output (including IDP), the K-TONE signal will be output continuously while keys are pressed.
Then, after the pulse dialing completes, the LC737212/M will pause for 3.9 seconds and then output the DTMF signals.
No. 5203-14/27
LC737212, 737212M
LC737212 and LC737212M Operat