Novatek NT91214 Series User manual

NT91214/15 Series
Tone/Pulse Dialer
1V1.0
Features
 One touch redial operation
 Tone/Pulse switchable
 32 digit capacity for redialing
 Automatic mixed redialing (last number redial) of pulse
to DTMF with multiple automatic access pauses
 PABX auto-pause is 2.2 seconds
 DTMF Timing:
Manual dialing: minimum duration for bursts and
pauses
Redialing: calibrated timing
 Hands-Free control function
 Wide operating voltage range: 2V to 5.5V
 Key-in beep tone output
 Digits dialed manually after redialing are cascadable
and stored as additional digits for the next redialing
 Uses inexpensive ceramic resonator (3.58 MHz)
 Two versions for different telephone systems
 Built-in power up reset circuit
 Four extra function keys: flash, pause, redial and DP
orDTMF mixed dialing
 4 x 4 (or 2 x 8) keyboard can be used
 Low standby current
General Description
The NT91214/15 is a single-chip, silicon gate, CMOS
integrated circuit with an on-chip oscillator for a 3.58MHz
crystal or ceramic resonator. It provides a dialing pulse
(DP) or dual tone multi-frequency (DTMF) dialing. A
standard 4 x 4 matrix keyboard can be used to support
either DP or DTMF modes.
Up to 32 digits can be saved in the on-chip RAM for
redialing. In the DTMF mode, a short minimum tone
duration and minimum intertone pause allows rapid
dialing. Maximum tone duration depends on the key
depression time during manual dialing.
Pin Configurations
a. 16-Pin Package b. 18-Pin Packages c. 20-Pin Package
(i) Key Tone Output (ii) Hands-Free Control

NT91214/15 Series
V1.02
Keyboard Assignments
123F1R1
456F2R2
789 P R3
*/T 0 # RD R4
C1 C2 C3 GND
1. */T -- In PULSE mode this key works as Pulse →DTMF key (T key). In DTMF mode the key works as * key.
*/T key will occupy one memory digit in either use.
2. F1 -- Flash key. The break time is 297 ms or 96 ms (NT91214/15 respectively)
3. F2 -- Flash key for break time 640 ms
4. P -- Pause key (2.2 seconds)
5. RD -- One key redial key
6. # -- In PULSE mode this key input is neglected. In DTMF mode this key works as # key.
Block Diagram

NT91214/15 Series
V1.03
Absolute Maximum Ratings*
Supply Voltage (VDD). . . . . . . . . . . . . . . . . . . .≤6.0V
Input Voltage (VIN) . . . . . . .VSS - 0.3V to VDD + 0.3V
Output Voltage (VOUT) . . . . VSS - 0.3V to VDD + 0.3V
Output Voltage (VOUT)(DP , XMIT MUTE ) . . . . ≤1.2V
Tone Output Current (ITONE) . . . . . . . . . . . . . . ≤50mA
Power Dissipation (PD) . . . . . . . . . . . . . . . . . ≤500mW
Operating Temperature (Top). . . . . . . -20°C to +70°C
Storage Temperature (Tstg). . . . . . . -40°C to +150°C
*Comments
Stresses above those listed under "Absolute Maximum
Ratings" may cause permanent damage to this device.
These are stress ratings only. Functional operation of
this device at these or any other conditions above those
indicated in the operational sections of this specification
is not implied or intended. Exposure to the absolute
maximum rating conditions for extended periods may
affect device reliability.
DC Electrical Characteristics (VDD = 3.5V, VSS = 0V, Fosc = 3.579MHz, Top = 25°C)
Parameter Symbol Min. Typ. Max. Unit Conditions Test
KT.
Operating Voltage VDD 2.0 5.5 VPULSE mode A
2.0 5.5 TONE mode
Memory Retention Voltage VMR 1V -
Memory Retention Current IMR 0.05 0.4 µAVDD = 1.0V, HK = VDD
All outputs unloaded -
Operating Current IDDP 0.32 1.0 mA Pulse mode All outputs A
IDDT 0.6 2.0 Tone mode unloaded
Standby Current Iso 0.03 0.05 µAHK = VDD= 1.5V All outputs
unloaded, A
0.5 10 HK = VSS no key
selected
Input Current VIH 0.8 1 VDD
VIL 00.2
R1 - R4 Input Current IR115 µAC
Tone out Voltage VOC 584 730 876 mVp-p Column VDD = 3.5V D
VOR 456 570 684 Row RL= 5K
HFI Pull Low Current IHFI5µAVDD = 3.5V (Note 1)
HFI pin connected to 0V B

NT91214/15 Series
4V1.0
DC Electrical Characteristics (continued)
Parameter Symbol Min. Typ. Max. Unit Conditions Test
KT.
HFO Drive Current IOH10.4 2 mA VDD = 3.5V
VOH = VDD- 0.4V B
HFO, KT , MODEOUT
XMITMUTE Sink Current IOL1 0.9 5.3 mA VDD = 3.5V
VOL = 0.4V B
DP Sink Current IOL2 1.1 5.3 mA VDD = 3.5V , VOL = 0.4V B
Distortion DIS% 1 5 % * see note below
* Note: DIS% = 100 *(V V ... V )
(V V )
22 2
22
1/2
1/2
12 n
IL IH
+++
+
1. V1. . . . Vnare the intermodulation or the harmonic frequencies in the 500Hz to 3400Hz band.
2. VIL and VIH are the individual frequency components of the DTMFsignal.
AC Characteristics (VDD = 3.5V, VSS = 0V, FOSC = 3.579MHz, Top = 25°C, unless otherwise specified.)
Parameter Symbol Min. Typ. Max. Unit Conditions
33.3 10pps M/B = 1/2
Make Time TM40.0 ms M/B = 2/3
16.7 20pps M/B = 1/2
20.0 M/B = 2/3
66.6 10pps M/B = 1/2
Break Time TB60.0 ms M/B = 2/3
33.3 20pps M/B = 1/2
30.0 M/B = 2/3
Inter-digit Pause Time TIDP 824 ms 10pps
458 20pps
Pause Time TPAU 2.2 sec

NT91214/15 Series
5V1.0
AC Characteristics (continued)
Parameter Symbol Min. Typ. Max. Unit Conditions
Auto-redial Break Time TAOBK 2.2 sec * Optional
Delay time Key valid to Signal Out TD0ms
Key-in Debounce TKD 21 ms
Key Release Debounce Time TKLD 5.2 ms
Key-in Tone Duration TKTD 23 ms
Key-in Tone Frequency FKT 437 HZ
Minimum Tone Duration Time TMFD 94 ms
Min. Tone Inter-digit Pause TTIDP 96 ms
Redial Tone Duration TMFDR 94 ms
Redial Tone Inter-digit Duration TTIDPR 96 ms
Comparisons of Specified vs. Actual Tone Frequencies
R/C Spec. Actual Error (%) Unit Conditions
R1 697 699.1 +0.31 Hz
R2 770 771.5 +0.19 Hz
R3 852 852.3 +0.03 Hz
R4 941 942.0 +0.10 Hz Fosc = 3.579MHz
C1 1,209 1,215.7 +0.57 Hz
C2 1,336 1,331.7 -0.32 Hz
C3 1,477 1,471.9 -0.35 Hz

NT91214/15 Series
6V1.0
Pin Descriptions
Pin No.
NT91215A
NT91214A NT91215B NT91214B NT91215C NT91214C NT91215D NT91214D
Designation I/O Description
3
43 44 54 5OSCI OSCO I Oscillator Input and Output pins The time base for the NT91214/15 is a
crystal controlled on-chip oscillator,
which is completed by connecting a
3.58MHz crystal or ceramic resonator
between the OSCI and OSCO pins.
2233MODEINI,ZTRI-STATEmodeselectpin
There are two versions of the
NT91214/15 as follows:
a. NT91215 Series is for European and
American systems.
MODE
IN Tone/ Pulse Dial Rate M/B Ratio
VDD Pulse 10pps 2/3
VSS Tone - -
Floating Pulse 10pps 1/2
b. The NT91214 Series is for the
Japanese system.
MODE
IN Tone/ Pulse Dial Rate M/B Ratio
VDD Pulse 10pps 1/2
VSS Tone - -
Floating Pulse 20pps 1/2
The mode selection pin is checked for
tone/pulse dialing as each digit key
entery. In the PULSE mode, the dialing
rate is checked, along with the
make/break ratio, at first key entry.

NT91214/15 Series
7V1.0
Pin Descriptions (continued)
Pin No.
NT91215A
NT91214A NT91215B NT91214B NT91215C NT91214C NT91215D NT91214D
Designation I/O Description
1122HK I Hook switch input
This inverter input pin detects the state
of the hook switch contact. "Off Hook" is
represented by a VSS condition. "On
Hook" is represented by a VDD
condition.
(N.A.) 10 (N.A.) 11 KT O Key-in tone output
This N-channel open drain pin sends out
a "beep" tone for each PULSE mode key
entry, along with entries of accepted
function keys (RD, T, F1 F2, and P
keys). The tone output frequency is
437Hz and tone duration is 23 ms.
9 111012 DP O Dialing pulse output
This is an N-channel open drain output.
The normal output will be "ON" during
break and "OFF" during make in the
PULSE DIALING mode.

NT91214/15 Series
8V1.0
Pin Descriptions (continued)
Pin No.
NT91215A
NT91214A NT91215B NT91214B NT91215C NT91214C NT91215D NT91214D
Designation I/O Description
1 1 HFO O Hands-Free Control I/O pins
These pins enable and disable the Hands-
Free control function. When input pin HFI
goes low, the Hands-Free Control state is
toggled on. The status of the Hands-Free
control state is listed in the following table:
(N.A.) (N.A.) Current
State Next State
Hook
sw. HFO Input HFO Dialing?
- Low HFI
↓
High Yes
18 20 HFI IOn
Hook High HFI
↓
Low No
Off
Hook High HFI
↓
Low Yes
On
Hook -Off Hook Low Yes
Off
Hook Low On Hook Low No
Off
Hook High On Hook High Yes
7788TONEOTonedialingoutput
When a valid keypress is detected in the
DTMF mode, appropriate low group and
high group, frequencies are generated
which hybridizes the dual tone output.
TONE output is in the "OFF" state in
PULSE mode.

NT91214/15 Series
9V1.0
Pin Descriptions (continued)
Pin No.
NT91215A
NT91214A NT91215B NT91214B NT91215C NT91214C NT91215D NT91214D
Designation I/O Description
8899
XMITMUTE O Dialing transmission mute output
This is an N-channel open drain output
The XMITMUTE is normally "OFF"
During pulse of DTMF dialing this
output is "ON".
(N.A.) 9 (N.A.) 10 MODE OUT O Mode output pin
This is an N-channel, open drain output
It is "ON" during tone output and "OFF"
during pulse output.
13 15 14 16 R1 Keyboard pins
14 16 15 17 R2 This input serves as the interface to an
XY matrix keyboard. On a 4 x 4 matrix
15 17 16 18 R3 keyboard, the input from the fourth
column,
C4 , should be connected to
16 18 17 19 R4 VSS.
10 12 11 13 C1
11 13 12 14 C2
12 14 13 15 C3
6677VDD Power supply pins
5566VSS These devices are designed to operate
from 2.0V to 5.5V.

NT91214/15 Series
10 V1.0
Operating Procedures
Symbol Definitions:
In the description below, signals are defined in terms of
the key or switch which is activated.
OFF Hook means the phone is off the hook.
On Hook means that the phone is on the hook.
D1 represents for the first digit dialed in a string of
digits.
Dn ( Dk ) represents for the last digit dialed in a
string of digits.
Dn+1 represents for the beginning of a new string of
digits.
Dn+m represents for the last digit in a new string of
digits.
HFI↓represents for the switch that activates the
HANDS-FREE DIALING mode going low
*/T is the Pulse-to-DTMF key
RD is the Redial key.
0 is the Zero key.
P is the Pause key.
F is the Flash key.
Recommended Operation:
1. PULSE mode operation
a. Off Hook D1 . . . Dn
PULSE mode is defined as the INITIAL mode,
provided
the first keyboard input is not the */T key following
the Off Hook condition and the mode selection pin
is
floating (MODE IN = VDD or floating).
b. On Hook HFI↓D1 . . . Dn
Pulse mode is defined as the INITIAL mode, provided
the key input D1 is not */T while the mode
selection pin is VDD or floating. The chip will pause for
824 ms automatically after it detects an Off Hook
condition or if the HFI↓key is depressed. It then
proceeds with pulse or DTMF dialing if any keys have
been depressed.
The dialing rate or make/break ratio is decided at the
first key entry by checking the MODE IN status and
will
not be altered. The MODE IN status can only switch
the DIALING mode from PULSE to DTMF after the
first
key entry.
2. DTMF mode operation
a. Off Hook D1 . . . Dn or On Hook HFI↓
D1 . . . Dn
DTMF mode is defined as the INITIAL mode if the
mode selection pin MODE IN is VSS.
b. Off Hook */T D1 . . . Dn or On Hook
HFI↓*/T D1 . . . Dn
The INITIAL mode is PULSE mode if the mode
selection pin, MODE IN, is VDD or floating. The */T
key can switch the DIALING mode to TONE mode.
Unlike NORMAL mode switching, the */T key
entry,

NT91214/15 Series
11 V1.0
as the first key pressed, will not produce any pause
time. There are only 31 digits of redial memory
available in the buffer to be used for operations a
and b, since the mode switching key, */T , will
occupy one digit of space.

NT91214/15 Series
12 V1.0
3. Manual dialing with automatic access pause
a. Off Hook O P D1 . . . Dn
pause key entries can be accepted and stored in the
redial memory. Each is stored as a digit.
Each key-in will provide a pause of 3.57 seconds,
depending on which model is being used.
4. Redial
a. On Hook RD or On Hook HFI↓RD
Up to 32 digits (in PULSE mode) or 31 digits
(in TONE mode) can be dialed using the RD key.
The RD key is disabled while PULSE or TONE
signals are being transmitted. Redial will also be
inhibited if the last number dialed exceeds 32 digits
because the redial memory can only hold 32 digits.
b. Off Hook RD D1 . . . Dn or On Hook
HFI↓RD D1 . . . Dn
After pressing the RD key, digits may be added to
the number in redial memory. When finished
dialing,
the redial memory will contain the original digits,
plus the digits dialed after pressing RD . Each time
the redial key is pressed, the stored number will be
dialed exactly the same as it was previously,
regardless of the status of the MODE IN pin.
5. TONE/PULSE switching operation
a. On Hook D1 . . . Dn MODE IN pin
PULSE Mode
switched to VSS Dn+1 . . . Dn+m
DTMF Mode
The mode selection pin is alwsys checked for TONE
or PULSE mode key entry. Dialing can be switched
from PULSE to TONE mode, but not from TONE to
PULSE mode. Switching the MODE IN pin to the
original digits plus the digits dialed after pressing will
cause the chip to store a */T digit prior to the first
tone digit in the redial memory and will automatically
insert a 2.2 second pause before the tone digits are
dialed out. After the mode bas been switched, the
status of the mode selection pin will no longer be
checked. Therefore, it will not be possible to switch
from TONE to PULSE mode.
b. Off Hook D1 . . . Dn */T Dn+1
PULSE Mode
. . . Dn+m
DTMF Mode
PULSE mode is initially defined with the mode
selection pin, MODE IN, equal to VDD or floating. At
this time, the mode can be switched to DTMF by
pressing the */T key. DTMF mode will being as soon
as the last pulse has been transmitted. In this mode,
Dn+1 through Dn+m are sent through the TONE
OUT pin as DTMF signals. If a P key entry is
Contained in the series of digits before or after the */T
entry, or the MODE IN switch is depressed, 2.2
second
pause will be added to the automatically inserted
pausetime, which is also 3.57 seconds. Both of the

NT91214/15 Series
13 V1.0
above switching modes can store as many as 31 digits
in the redial memory.

NT91214/15 Series
14 V1.0
6. One-key redialing
Off Hook D1 . . . Dn RD or On Hook HFI↓
D1 . . . Dn RD
If the dialing of D1 to Dn is finished, pressing
RD will cause the pulse dialing pin to go low for 1.67
seconds of break time and an 824 ms pause will
automatically be added. If the pulses of the number
dialed with D1 to Dn have not finished, the
pressing of the redial key will be ignored.
7. Flash dialing
Off Hook F D1 . . . Dn or On Hook
HFI↓F D1 . . . Dn
The flash keys emulate quick On-Off Hook operations.
Pressing the flash keys, F1 or F2 , will cause a
break of 96 ms or 640 ms (or, 297 ms or 640 ms,
depending on the model) on the DP output pin. Then, it
pauses for 824 ms and continues dialing the digits,
D1 to Dn . These digits are then stored in the redial
memory.
Each time the flash key is pressed, the redial memory
will
be cleared to store a new entry. In addition, the MODE
IN
status will be checked again for the setting of the
TONE/PULSE DIALING mode.
Similarly, to make sure that the IC is working properly,
new flash key inputs will be ignored as long as the digits
that were dialed have not finished.
Timing Waveforms
1. Timing Waveform in PULSE Mode:
Key Input 2 3
XMIT MUTE
HK or HFO
1
KT T
KD
: debouncing time 21 ms
T
KTD
(23 ms), f = 437Hz
T
d
T
IDP
T
M
T
M
21ms
T
M
T
B
DP
Td: Delay time of Key valid to dialing signal out, typically 0ms
TIDP: Inter-digit pause time
TKTO: Key-in tone duration
TKD: Debouncing time
Note: "HK " or "HFO" indicates chip works when hook switch "HK " goes low or Hands-Free control output HFO goes
high.

NT91214/15 Series
15 V1.0
Timing Waveforms (continued)
2. Timing Waveform in TONE Mode:
(i) Normal Dialing
Key Input 4 9
XMIT MUTE
HK or HFO
*
KT T
KD
T
d
TMFD:94ms
2.3ms
3
2.5ms 2.3ms 2.3ms
TONE T
TIDP
:96ms
MODE OUT
(ii) After (i), Redialing
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NT91214/15 Series
16 V1.0
Timing Waveforms (continued)
3. Timing waveform for SWITCHING Mode Operation:
(i) By mode selection pin switches
Key Input 2 4
XMIT MUTE
HK or HFO
*/T
KT
T
M
3
TONE
MODE OUT
6
**** ***********************
MODE IN
DP
T
IDP
T
M
T
IDP
T
IDP
T
IDP
T
d
T
PAU
T
MFD
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TPAU: Pause time (2.2 secs)

NT91214/15 Series
17 V1.0
Timing Waveforms(continued)
4. One Key Redial (DTMF mode used as example):
Key Input 2
XMIT MUTE
HK or HFO
RD
T
d
3
TONE
MODE OUT
DP
2.5ms
T
AOBK
T
d
2.5ms
TAOBK: Break time (2.2 secs)
5. Flash Dialing (DTMF mode used as example):
Key Input F
XMIT MUTE
HK or HFO
TONE
MODE OUT
DP T
fsh
T
PAU
2.5ms
//
64 3
//
2.5ms
//
//
//
//
Tfsh: flash time 96 or 640 ms (F1 or F2 respectively) for NT91215
flash time 297 or 640 ms (F1 or F2 respectively) for NT91214

NT91214/15 Series
18 V1.0
Application Circuit (for reference only)
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NT91214/15 Series
19 V1.0
Test Circuits
(A) (B)
(C) (D)
OSCILLOSCOPE: TEKTRONI X 468
SPECTURM ANALYZER: HP3585A

NT91214/15 Series
20 V1.0
Ordering Information
Part No. Key Tone Hands-Free Dial Rate M/B Ratio Flash Package
Control F1 F2
NT91214A N.A. N.A. 16L DIP
NT91214B A N.A. 10/20pps 1/2 297 ms 640 ms 18L DIP
NT91214C N.A. A 18L DIP
NT91214D A A 20L DIP
NT91215A N.A. N.A. 16L DIP
NT91215B A N.A. 10pps 1/2 96 ms 640 ms 18L DIP
NT91215C N.A. A 2/3 selectable 18L DIP
NT91215D A A 20L DIP