MC34017
MAXIMUM RATINGS
(Voltages Referenced to RG, Pin 7)
Rating
Operating AC Input Current (Pins 1, 8)
Transient Input Current (Pins 1, 8) (T<2.0 ms)
Voltage Applied at RC (Pin 6)
Voltage Applied at RS (Pin 5)
Voltage Applied to Outputs (Pins 2, 3)
Power Dissipation (@ 25°C)
Operating Ambient Temperature
Storage Temperature
NOTE:
ESD data available upon request.
Symbol
–
Vin
VRC
VRS
VO
PD
TA
Tstg
Value
20
±300
5.0
5.0
–2.0 to VRI
1.0
–20 to +60
–65 to +150
Unit
mA, RMS
mA, peak
V
V
V
W
°C
°C
ELECTRICAL CHARACTERISTICS
(TA = 25°C)
Characteristic
Ringing Start Voltage
VStart = VI at Ring Start
VI > 0
VI < 0
Ringing Stop Voltage
VStop = VI at Ring Stop
MC34017–1
MC34017–2
MC34017–3
Output Frequencies (VI = 50 V)
MC34017–1 High Tone
MC34017–1
Low Tone
MC34017–1
Warble Tone
MC34017–2 High Tone
MC34017–1
Low Tone
MC34017–1
Warble Tone
MC34017–3 High Tone
MC34017–1
Low Tone
MC34017–1
Warble Tone
Output Voltage (VI = 50 V)
Output Short–Circuit Current
Input Diode Voltage (II = 5.0 mA)
Input Voltage – SCR “Off” (II = 30 mA)
Input Voltage – SCR “On” (II = 100 mA)
RS Clamp Voltage (VI = 50 V)
Test
Symbol
Min
Typ
Max
Unit
Vdc
1a
1b
1c
VStart (+)
VStart (–)
VStop
14
12
14
1d
fH
fL
fW
fH
fL
fW
fH
fL
fW
6
2
3
4a
4b
5
VO
IRO1, IRO2
VD
Voff
Von
Vclamp
937
752
11.5
1874
1504
11.5
937
752
23
34
35
5.4
30
3.2
1.3
1010
808
12.5
2020
1616
12.5
1010
808
25
37
60
6.2
38
4.1
1.5
1083
868
14
2166
1736
14
1083
868
28
43
80
6.8
43
6.0
1.8
Vpp
mApp
Vdc
Vdc
Vdc
Vdc
16
14
16
22
20
22
Hz
34
–34
37.5
–37.5
41
–41
Vdc
PIN FUNCTION DESCRIPTION
Pin
1, 8
5
4
2, 3
7
6
Symbol
AC1, AC2
RS
RI
RO1, RO2
RG
RC
Description
The input terminals to the full–wave diode bridge. The ac ringing signal from the telephone line energizes the
ringer through this bridge.
The input of the threshold comparator to which diode bridge current is mirrored and sensed through an external
resistor (R3). Nominal threshold is 1.2 V. This pin internally clamps at 1.5 V.
The positive supply terminal for the oscillator, frequency divider and output buffer circuits.
The tone ringer output terminals through which the sound element is driven.
The negative terminal of the diode bridge and the negative supply terminal of the tone generating circuitry.
The oscillator terminal for the external resistor and capacitor which control the tone ringer frequencies (R2, C2).
2
MOTOROLA ANALOG IC DEVICE DATA
MC34017
CIRCUIT DESCRIPTION
The MC34017 Tone Ringer derives its power supply by
rectifying the ac ringing signal. It uses this power to activate
a tone generator and drive a piezo–ceramic transducer. The
tone generation circuitry includes a relaxation oscillator and
frequency dividers which produce high and low frequency
tones as well as the tone warble frequency. The relaxation
oscillator frequency fo is set by resistor R2 and capacitor C2
connected to Pin RC. The oscillator will operate with fo from
1.0 kHz to 10 kHz with the proper choice of external
components (see Figure 1).
The frequency of the tone ringer output signal at RO1 and
RO2 alternates between fo/4 to fo/5. The warble rate at which
the frequency changes is fo/320 for the MC34017–1, fo/640
for the MC34017–2 and fo/160 for the MC34017–3. With a
4.0 kHz oscillator frequency, the MC34017–1 produces
800 Hz and 1000 Hz tones with a 12.5 Hz warble rate. The
MC34017–2 generates 1600 Hz and 2000 Hz tones with a
similar 12.5 Hz warble frequency from an 8.0 kHz oscillator
frequency. The MC34017–3 will produce 400 Hz and 500 Hz
tones with a 12.5 Hz warble rate from a 2.0 kHz oscillator
frequency. The tone ringer output circuit can source or sink
20 mA with an output voltage swing of 37 V peak–to–peak.
Volume control is readily implemented by adding a variable
resistance in series with the piezo transducer.
Input signal detection circuitry activates the tone ringer
output when the ac line voltage exceeds programmed
threshold level. Resistor R3 determines the ringing signal
amplitude at which an output signal at RO1 and RO2 will be
generated. The ac ringing signal is rectified by the internal
diode bridge. The rectified input signal produces a voltage
across R3 which is referenced to RG. The voltage across
resistor R3 is filtered by capacitor C3 at the input to the
threshold circuit.
Figure 1. Oscillator Period (1/fo) versus
Oscillator R2 C2 Product
800
1/fo, OSCILLATOR PERIOD (
µ
s)
When the voltage on capacitor C3 exceeds 1.2 V, the
threshold comparator enables the tone ringer output. Line
transients produced by pulse dialing telephones do not charge
capacitor C3 sufficiently to activate the tone ringer output.
Capacitors C1 and C4 and resistor R1 determine the 10 V,
24 Hz signature test impedance. C4 also provides filtering for
the output stage power supply to prevent droop in the square
wave output signal. Six diodes in series with the rectifying
bridge provide the necessary non–linearity for the 2.5 V,
24 Hz signature tests.
An internal shunt voltage regulator between the RI and RG
terminals provides dc voltage to power the output stage,
oscillator and frequency dividers. The dc voltage at RI is
limited to approximately 22 V in regulation. To protect the IC
from telephone line transients, an SCR is triggered when the
regulator current exceeds 50 mA. The SCR diverts current
from the shunt regulator and reduces the power dissipation
within the IC.
EXTERNAL COMPONENTS
R1
Line Input Resistor
R1 affects the tone ringer input impedance. It
also influences ringing threshold voltage and
limits current from line transients.
(Range: 2.0 to 10 kΩ).
Line Input Capacitor
C1 ac couples the tone ringer to the telephone
line and controls ringer input impedance at low
frequencies.
(Range: 0.4 to 2.0
µF).
Oscillator Resistor
(Range: 150 to 300 kΩ).
Oscillator Capacitor
(Range: 400 to 3000 pF).
Input Current Sense Resistor
R3 controls the ringing threshold voltage.
Increasing R3 decreases the ring–start voltage.
(Range: 5.0 to 18 kΩ).
Ringing Threshold Filter Capacitor
C3 filters the ac voltage across R3 at the input
of the ringing threshold comparator. It also
provides dialer transient rejection.
(Range: 0.5 to 5.0
µF).
Ringer Supply Capacitor
C4 filters supply voltage for the tone generating
circuits. It also provides an ac current path for
the 10 Vrms ringer signature impedance.
(Range: 1.0 to 10
µF).
C1
R2
C2
R3
600
C3
400
C4
200
150 k
≤
R2
≤
300 k
400 pF
≤
C2
≤
3000 pF
0
0
100
200
300
400
500
R2 C2, OSCILLATOR R2 C2 PRODUCT (µs)
(1/fo = 1.45 R2 C2 + 10
µs)
4
MOTOROLA ANALOG IC DEVICE DATA
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