Datasheet MC34216ADW Datasheet (Motorola)

T

A

= 0° to +70°C

Device

Operating

Temperature Range

Package



SEMICONDUCTOR

TECHNICAL DATA

PROGRAMMABLE
TELEPHONE LINE

INTERFACE CIRCUIT WITH

LOUDSPEAKER AMPLIFIER

ORDERING INFORMATION

MC34216ADW SO–28L

DW, DWF SUFFIX

PLASTIC PACKAGE

CASE 751F

28

1

PIN CONNECTIONS

Order this document by MC34216A/D

1 28

27
26
25
24
23
22
21

2
3
4
5
6
7
8

AHO1
AHO2

MTF
MTC

Mic

AGC

RXO1

LPI

Gnd
V

CC

20

9

LAO

LAI

I

ref

1910

HYN

R

S

LPO

RXI

RXO2

AGnd

TXI

(Top View)

18

11

NDC

Clk

17

12

CM D/HS

16

13

IMP

Osc

15

14

SAO SAI

MC34216ADWF SO–28L

1

MOTOROLA ANALOG IC DEVICE DATA

 

 
    !
  

The MC34216A is developed for use in telephone applications where,
besides the standard telephone functions, the group listening–in feature is
also required. In cooperation with a microcontroller, the circuit performs all
basic telephone functions including DTMF generation and pulse–dialing.
The listening–in part includes a loudspeaker amplifier, an anti–howling
circuit and a strong supply. In combination with the TCA3385, the ringing is
performed via the loudspeaker.

• Programmable DC Mask, for France, U.K., and Voltage Regulated

Countries

• DC Mask for France and U.K. (MC34216ADWF)

• Programmable Volume for Listening–In and Ringing

• Small Amount of External Components

• On–Chip DTMF and Ring Signal Generator

• Efficient Supply Point for Loudspeaker Amplifier and Peripherals

• Programmable Modes for Speakerphone, Answering Machine, Fax and

Modem Applications

• Pilot and Idle Tones Provide Extra Phone Features

Simplified Block Diagram

This device contains 6,507 active transistors.

Line

Driver

Anti–

Howling

Mic

Supply

Stabilizer

DC Mask

Generation AC

Termination 2–4

Wire Conversion

DC and AC
Termination

Handset

Earpiece

Handset

MIcrophone

Line –

Line +

LSP

Base

Loudspeaker

Micro-

controller

Interface

DTMF and

Ring

Generator

Ear

This document contains information on a new product. Specifications and information
herein are subject to change without notice.

 Motorola, Inc. 1996

MC34216A

2

MOTOROLA ANALOG IC DEVICE DATA

FEATURES

Line Driver and Supply

• DC and AC Termination of the Line

• Programmable DC Mask: France, U.K., Startup, Low Voltage (MC34216ADW)

• Programmable DC Mask: France, U.K., Startup (MC34216ADWF)

• Current Protection

• Adjustable Set Impedance for Resistive and Complex Termination

• Efficient Supply Point for Loudspeaker Amplifier and Peripherals

Handset Operation

• Transmit and Receive Amplifiers

• Adjustable Sidetone Network

• Line Length AGC

• Microphone and Earpiece Mute

• Earpiece Gain Increase Switch

• Microphone Squelch Function

• Transmit Amplifier Soft Clipping

Dialing and Ringing

• Generates DTMF, Pilot Tones and Ring Signal

• Interrupter Driver for Pulse–Dialing

• Low Current While Pulse–Dialing

• Optimized for Ringing via Loudspeaker

• Programmable Ring Melodies

• Uses Inexpensive 500 kHz Resonator

Loudspeaking Facility

• Integrated Loudspeaker Amplifier

• Peak–to–Peak Limiter Prevents Distortion

• Programmable Volume

• Anti–Howling Circuitry for Group Listening–In

• Interfacing for Handsfree Conversation

Application Areas

• Corded Telephony with Group Listening–In

• Cordless Telephony Base Station with Group Listening–In

• Telephones with Answering Machines

• Fax, Intercom, Modem

MAXIMUM RATINGS

Rating Symbol Min Max Unit

Maximum Junction Temperature T

J

– +150 °C

Storage Temperature Range T

stg

– 65 +150 °C

NOTES: 1. Devices should not be operated at or outside these values. The “Recommended

Operating Limits” provide for actual device operation.

2.ESD data available upon request.

RECOMMENDED OPERATING CONDITIONS

Characteristic Symbol Min Typ Max Unit

Oscillator Frequency @ Pin 16

f

osc

495

500

505

ÁÁÁ

ÁÁÁ

ÁÁÁ

kHz

Operating Temperature Range

T

A

0

–

+70

ÁÁÁ

ÁÁÁ

ÁÁÁ

°C

MC34216A

3

MOTOROLA ANALOG IC DEVICE DATA

DC ELECTRICAL CHARACTERISTICS (T

A

= 25°C)

Characteristic

Symbol Min Typ Max Unit

VOLTAGE REGULATOR

Regulated Supply at Pin 21

Vdc

Startup Mode

ICC = 10 mA V

CC1

4.25 4.50 4.75

ICC = 100 mA 4.40 4.65 4.90

France and U.K.

ICC = 10 mA V

CC2

4.25 4.50 4.75

ICC = 50 mA 4.30 4.55 4.85

Low Voltage Mode (MC34216ADW Only)

ICC = 10 mA V

CC3

3.60 3.90 4.20

ICC = 100 mA 3.75 4.05 4.35

Current Consumption at Pin 21, Bit LD = Hi

ICC LD

–

1.2

–

mA

Regulated Supply in Protection Mode, ICC = 30 mA

V

CC5

4.30

–

4.80

Vdc

Reference Current @ Pin 20

I

ref

15.3

16.3

17.3

µA

LOGIC PINS

Hook Status Output (Pin 17)

Vdc

Off–Hook, I

out

= – 200 µA V

HSO1

VCC – 1.0 – –

On–Hook, I

out

= 200 µA V

HSO2

– – 0.4

Bit LD = 1, I

out

= – 200 µA V

HSO3

VCC – 1.0 – –

Reset Output (Pin 19)

Vdc

VCC < 3.0 V V

res(on)

– – 0.40

VCC > 3.25 V V

res(off)

3.0 – VCC – 0.1

Hysteresis V

res(hys)

– 0.05 –

SPEECH AMPLIFIERS

Earpiece Amplifier DC Bias

Vdc

RXI, Pin 25 V

RXI

1.7 – 2.3

RXO1, Pin 26 V

RXO1

1.7 – 2.5

RXO2, Pin 27 V

RXO2

1.7 – 2.5

RXO1 – RXO2 Offset V

offset

– – 0.4

Loudspeaker Amplifier

Vdc

LPI, Pin 24 V

LPI

1.9 – 2.5

LPO, Pin 23 V

LPO

1.9 – 2.5

AHO1 (Pin 1)

Vdc

Normal Mode (HPI = 0) V

AHO11

1.15 – 1.65

Supervision Mode (HPI = 1) V

AHO12

2.2 – 2.8

AHO2 (Pin 2)

Vdc

Normal Mode (MicM = 1)

V

AHO21

1.15 – 1.65

VCC = 3.5 (MicM = 0) V

AHO22

– – 0.20

Bias Voltage at HYN (Pin 10)

Vdc

Normal Mode V

HYN

2.4 – 2.7

Bit (LD = 1) V

HYN–LD

1.4 – 1.7

Microphone Amplifier

Bias Voltage @ TXI (Pin 6) V

TXI

1.7 – 2.0 Vdc

Voltage at MIC @ 1.0 mA ( MicP = 1) V

Mic

– – 0.35

Leakage @ MIC @ 4.5 V (MicP = 0) I

leak

– – 5.5 µA

LAO (Pin 8)

Maximum Current (Source) I8 – –150 –110 µA
Maximum Current (Sink) I8 110 150 –
Voltage (LD = 1, I = 100 µA) V

LAO

– – 350 mV

Driver A8 Slope S8 1.6 2.1 2.6 µA/mV

VO1 Follower (I2 = 0 µA)

V

O1

1.1

1.18

1.3

V

VO1 – V

O2

∆V

O

40 80 120 mV

Voltage at IMP (Pin 13)

V

IMP

2.2

–

2.5

Vdc

MC34216A

4

MOTOROLA ANALOG IC DEVICE DATA

DC ELECTRICAL CHARACTERISTICS

(continued) (TA = 25°C)

Characteristic UnitMaxTypMinSymbol

DC MASK CHARACTERISTICS

Startup Mode

Internal Slope ri 300 380 460 mV/µA
Voltage on SAI (I2C = 5.9 µA) V

C

800 – – mV

Voltage on SAI (I2D = 7.1 µA) V

D

– – 1.5 V

Delta Offset Voltage on SAI (I2E = 38 µA) VE – V

D

– – 100 mV

French

Internal Slope ri 76 103 130 mV/µA
Voltage on SAI (I2C = 5.9 µA) V

C

280 – – mV

Voltage on SAI (I2D = 7.1 µA) V

D

– – 460

Delta Offset Voltage on SAI (I2E = 38 µA) VE – V

D

– – 30

U.K.

Internal Slope ri 120 165 210 mV/µA
Voltage on SAI (I2C = 5.9 µA) V

C

420 – – mV

Voltage on SAI (I2D = 7.1 µA) V

D

– – 675

Delta Offset Voltage on SAI (I2E = 38 µA) VE – V

D

– – 40

Low Voltage Mode (MC34216ADW Only)

Internal Slope ri 95 129 165 mV/µA
Voltage on SAI (I2C = 15 µA) V

C

900 – – mV

Voltage on SAI (I2D = 17 µA) V

D

– – 1.5 Vdc

Delta Offset Voltage on SAI (I2E = 20 µA) VE – V

D

– – 100 mV

Overvoltage Protection Threshold (V

LAI

– V

SAO

)

V

clamp1

485

550

615

mV

I

prot

= 60 µA, ICC = 70 mA

Protection Voltage Level (V

LAI

– V

SAO

)

V

clamp2

370

410

450

mV

I

prot

= 60 µA

AC ELECTRICAL CHARACTERISTICS (T

A

= 25°C)

Characteristic

Symbol Min Typ Max Unit

TRANSMIT MODE

French and U.K.

dB

Maximum Transmit Gain (I2 = 5.6 µA) K

µ0

13.5 14.5 15.5

Line Length Regulation (I2 = 27.5 µA) ∆K

µ

5.0 6.0 7.0

Gain in Protection Mode (I2 = 29.5 µA) K

µp

13.5 14.5 15.5

Low Voltage Mode (MC34216ADW Only)

dB

Maximum Transmit Gain (I2 = 3.5 µA) K

µ0

13.5 14.5 15.5

Line Length Regulation (I2 = 7.7 µA) ∆K

µ

4.7 6.0 7.3

Gain in Protection Mode (I2 = 7.7 µA) K

µp

13.5 14.5 15.5

Gain Reduction when Microphone is Muted

∆K

mute

60

–

–

dB

RECEIVE MODE

French

Maximum Internal Transconductance (I2 = 5.6 µA) G

e0

203 230 258 µA/V

Line Length Regulation (I2 = 26 µA) ∆G

e

5.0 6.0 7.0 dB

Protection Mode (I2 = 26 µA) G

ep

203 230 258 µA/V

U.K.

Maximum Internal Transconductance (I2 = 5.6 µA) G

e0

203 230 258 µA/V

Line Length Regulation (I2 = 26 µA) ∆G

e

5.0 6.0 7.0 dB

Protection Mode (I2 = 26 µA) G

ep

203 230 258 µA/V

Low Voltage Mode (MC34216ADW Only)

Maximum Internal Transconductance (I2 = 3.5 µA) G

e0

183 210 241 µA/V

Line Length Regulation (I2 = 7.9 µA) ∆G

e

4.7 6.0 7.3 dB

Protection Mode (I2 = 7.9 µA) G

ep

183 210 241 µA/V

Earpiece Gain Reduction when Muted

∆Ge

mute

60

–

–

dB

Earpiece Gain Variation (EA Bit Changed to 1)

∆G

e1

4.6

5.6

6.6

dB

MC34216A

5

MOTOROLA ANALOG IC DEVICE DATA

AC ELECTRICAL CHARACTERISTICS (continued) (T

A

= 25°C)

Characteristic UnitMaxTypMinSymbol

TRANSMIT PABX MODE

French and U.K.

dB

Transmit Gain (I2 = 2.0 µA) K

PABX

11.4 12.5 13.6

Variation with Line Length (I2 = 27 µA) ∆K

PABX

–0.5 – 0.5

Low Voltage Mode (MC34216ADW Only)

dB

Transmit Gain (I2 = 2.0 µA) K

PABX

11.5 12.5 13.6

Variation with Line Length (I2 = 20 µA) ∆K

PABX

–0.5 – 0.5

Variation with Line Current (ICC = 16 mA) ∆K

PABX1

–0.5 0 0.5

Variation with Line Current (ICC = 7.0 mA) ∆K

PABX2

–2.0 0 2.0

RECEIVE PABX MODE

French

Internal Transconductance (I2 = 2.0 µA) G

PABX

157 180 207 µA/V

Variation with Line Length (I2 = 27 µA) ∆G

PABX

–0.5 – 0.5 dB

U.K.

Internal Transconductance (I2 = 2.0 µA) G

PABX

157 180 207 µA/V

Variation with Line Length (I2 = 27 µA) ∆G

PABX

–0.5 – 0.5 dB

Low Voltage Mode (MC34216ADW Only)

Internal Transconductance (I2 = 2.0 µA) G

PABX

152 175 200 µA/V

Variation with Line Length (I2 = 20 µA) ∆G

PABX

–0.5 – 0.5 dB

Variation with Line Current (ICC = 16 mA) ∆G

PABX1

–0.5 – 0.5

Variation with Line Current (ICC = 7.0 mA) ∆G

PABX2

–2.0 – 2.0

DISTORTION

French and U.K. Transmit (I2 = 10–30 µA)
French Receive VE = 700 mV

(I2 = 10 µA) VE = 1350 mV

THDT
THDR

–
–
–

–
–
–

3.0

3.0

5.0

%

Low Voltage Transmit (I2 = 10–20 µA)
(MC34216ADW Only) Receive VE = 700 mV

(I2 = 20 µA) VE = 1350 mV

THDT
THDR

–
–
–

–
–
–

3.0

3.0

5.0

%

NOTE: VE is the differential earpiece voltage across Pins 26 and 27.

OTHER ELECTRICAL CHARACTERISTICS (T

A

= 25°C)

Characteristic

Symbol Min Typ Max Unit

LINE CURRENT AGC ( RLS = 25 Ω, G0 = G1 = G2 = 1, VLS = 2.0 Vpp, French, U.K., and LV Masks)

Line Current for which AGC is Active

I

AGC(on)

–

–

19

mA

VCC with Current AGC “On” (ICC = 13 mA)

VCC

AGCVCC

– 5.0%

V

CC

–

Vdc

Line Current for which AGC is Inactive

I

AGC(off)

21

–

–

mA

PEAK–TO–PEAK AGC (RLS = 25 Ω, C25 = 220 nF, G0 = G1 = G2 = 1, ICC = 40 mA)

DC Level at Pin 28

Vdc

AGC “Off” V

AGC(off)

1.6 1.7 1.8

AGC “On” V

AGC(on)

1.2 1.3 1.5

AGC Upper Threshold

V

LS(up)

V

rms

France and U.K. VCC – 1.2 VCC – 1.0 –
Low Voltage (MC34216ADW Only) 0.85 1.0 –

AGC Lower Threshold

V

LS(low)

V

rms

France and U.K. VCC – 1.9 VCC – 1.6 –
Low Voltage (MC34216ADW Only) 0.72 0.85 –

1 Step AGC Gain Variation (LSB)

∆AGC

1.0

1.25

1.50

dB

ANTI–HOWLING MONITORING RECEIVE GAIN

Internal Resistor R

T

Muted (G2, G1, G0 = 000) R

T000

– 10 18 Ω

Maximum Gain (G2, G1, G0 = 111) R

T111

40 60 80 kΩ

Attenuation Step

∆G

LS

3.5

4.5

5.5

dB

MC34216A

6

MOTOROLA ANALOG IC DEVICE DATA

OTHER ELECTRICAL CHARACTERISTICS

(continued) (TA = 25°C)

Characteristic UnitMaxTypMinSymbol

RINGING MODE REGULATION

Regulated VCC (RLS = ∞, ICC = 10 mA)

VCCR

5.15

5.5

5.8

Vdc

Current Consumption @ VCC = 3.4 V, RLS = ∞

IcR

–

2.0

2.6

mA

Ringing Regulator Slope

gR

4.8

6.3

7.8

µA/V

Peak Current @ VCC = 4.2 V

IR Peak

2.0

2.5

3.0

µA

Minimum V

CC

V

CC0

–

3.8

–

Vdc

MICROPHONE THRESHOLD

Transmit Gain Variation (M

th(on)/Mth(off)

)

dB

Iu = 33 nA ∆K

µmth1

– 7.0 –

Iu = 110 nA ∆K

µmth2

–0.5 0 0.5

LS Gain Variation (M

th(on)/Mth(off)

)

dB

Iu = 33 nA ∆G

LSmth1

–0.5 0 0.5

Iu = 110 nA ∆G

LSmth2

– 7.0 –

SPEAKERPHONE MODE (G2, G1, G0 = 111, Sp Bit = 1)

DC Level on Pin 1

V

AHO1

2.2

–

2.8

Vdc

Speakerphone Gain

G

sp

30

32

34

dB

MONITORING SIGNAL IN LOUDSPEAKER (R/S = 0, G2, G1, G0 = 111)

DTMF Level

mV

SP = 0

Low Frequency V

LS–L1

– 200 –

High Frequency V

LS–H1

– 250 –

SP = 1

Low Frequency V

LS–L2

– 700 –

High Frequency V

LS–H2

– 900 –

Pilot Tone (PT = 1)

mV

SP = 0 V

LS–P1

– 185 –

SP = 1 V

LS–P2

– 560 –

Idle Tone (IT = 1)

mV

SP = 0 V

LS–I1

– 145 –

SP = 1 V

LS–I2

– 700 –

Ring Tone (RT = 1)

mV

SP = 0 V

LS–R1

– 1100 –

SP = 1 V

LS–R2

– 1400 –

MONITORING SIGNAL IN EARPIECE (Single Ended)

DTMF Level

mV

Low Frequency V

RXO–L

– 12 –

High Frequency V

RXO–H

– 15 –

Pilot Tone (PT = 1)

V

RXO–P

–

8.0

–

mV

Idle Tone (IT = 1)

V

RXO–I

–

6.0

–

mV

IDLE TONE ON LINE

Idle Tone Level (MFC01 = 11, MFO123 = 000)

I

IDLE0

400

550

700

nA

Step Size

I

IDLE(step)

–

62

–

nA

DTMF LEVELS

Level on LAI (Pin 9, ICC = 20 to 70 mA, French and U.K. Masks)

nA

MFO123 = 1111, High Frequency Group I

DTMF15

1124 1336 1586

MFO123 = 0111, High Frequency Group I

DTMF12

988 1175 1397

MFO123 = 0000, Low Frequency Group I

DTMF0

373 444 528

High/Low Frequency Pre–Emphasis

G

DTMF

1.0

2.0

3.0

dB

NOTE: In low voltage mode, above levels must be reduced by 0.5 dB.

MC34216A

7

MOTOROLA ANALOG IC DEVICE DATA

DTMF FREQUENCIES

Characteristic Min Typ Max Unit DTMF Std % Error

Low Group Frequencies

689.4

696.4

703.4

Hz

697

–0.09

761.5

769.2

776.9

Hz

770

–0.10

844.7

853.2

861.7

Hz

852

0.14

930.5

939.9

949.3

Hz

941

–0.11

High Group Frequencies

1195.6

1207.7

1219.8

Hz

1209

–0.11

1323.5

1336.9

1350.3

Hz

1336

0.07

1464.5

1479.3

1494.1

Hz

1477

0.16

1617.7

1634

1650.3

Hz

1633

0.06

NOTE: Minimum values based on f

osc

= 495 kHz. Maximum values based on f

osc

= 505 kHz.

TEMPERATURE SPECIFICATIONS (T

A

= 65°C)

Characteristic

Symbol Min Max Unit

DTMF Distortion Level on Pin LAI, Delta Levels

(F = Hi Freq – f = 697 Hz)

DTMFD – –27 dB

V

CC2

in FR Mode @ ICC = 50 mA V

CC2

4.15 5.0 V

V

CCR

@ ICC = 10 mA, RLS = ∞ V

CCR

5.0 6.0 V

VC on Pin SAI in FR Mode V

C

220 460 mV
Ri Slope in FR Mode Ri 65 155 kΩ
RT111 Resistor on LS in FR Mode RT111 35 85 kΩ
Kµ0 in FR Mode K

µ0

13 16 dB

Ge0 in FR Mode G

e0

170 270 µA/V
Reset Off @ VCC = 3.25 V V

resoff

3.0 3.25 V

PIN FUNCTION DESCRIPTION

Pin Symbol Description

1 AHO1 Anti–Howling Timing, Speakerphone Input
2 AHO2 Anti–Howling Timing, Low Voltage Line Driver Disable
3 MTF Microphone Threshold Filtering
4 MTC Microphone Threshold Timing
5 AGnd Small Signal Ground
6 TXI Microphone Amplifier Input
7 Mic Microphone Bias Current Sink
8 LAO Line Driver Amplifier Output

9 LAI Line Driver Amplifier Input
10 HYN Hybrid Network Input
11 NDC Noise Decoupling
12 CM DC Mask Signal Filtering
13 IMP Reference Voltage
14 SAO Line Current Sense Amplifier Output
15 SAI Line Current Sense Amplifier Input
16 Osc Oscillator Input. Connect to 500 kHz Resonator
17 D/HS Data Input, Hookstatus Output
18 Clk Clock Input
19 R

S

Reset Output

20 I

ref

Reference Current

MC34216A

8

MOTOROLA ANALOG IC DEVICE DATA

PIN FUNCTION DESCRIPTION (continued)

Pin DescriptionSymbol

21 V

CC

Supply Voltage
22 Gnd Large Signal Ground
23 LPO Loudspeaker Amplifier Output
24 LPI Loudspeaker Amplifier Input
25 RXI Receive Amplifier Input
26 RXO1 Receive Amplifier Output
27 RXO2 Receive Amplifier Output
28 AGC Loudspeaker AGC Timing

CIRCUIT DESCRIPTION

Concept

With the MC34216A, a microcontroller and a switched
mode power supply , a telephone set with listening–in function
and ringing via loudspeaker can be built as shown in
Figure 1.

In off–hook position, the application is in speech mode. The
line current flows through transistor T2 and supplies the
application at the supply point VCC which is stabilized by the
MC34216A. The V

line

, I

line

characteristic is programmed by
the microcontroller and adjusted by the external components
Z0, Z1, Z21 and R1 which are in a regulator loop, acting on
transistor T2. The ac impedance is generated in a similar way.
Handset and loudspeaker can be connected directly to the

MC34216A to perform handset and listening–in operation.
Via the bus, the microcontroller programs the MC34216A to
perform the DTMF/pulse–dialing and supervise the device.
The user keyboard has to be connected to the microcontroller.

In on–hook position, the SMPS supplies the application in
presence of a ringing signal. The microcontroller programs
the MC34216A and a ringing melody can be generated via
the loudspeaker.

The block diagram of the MC34216A (see Figure 2),
shows the basic blocks of the device plus the essential
external components.

R1

MicroMC34216A

T2

Z0

Z1

Z21

A/B

Hookswitch

V

CC

Gnd

SMPS

Loudspeaker

Handset

Figure 1. Telephone Concept with MC34216A

MC34216A

9

MOTOROLA ANALOG IC DEVICE DATA

T2

C7

RXO1

Z0

Z21

Z1

T3

C20

R6

R9

C5

R12R20

RXO2

TXI

Mic

AHO1 MTCMTFAHO2

RXI

LAO

Gnd

V

HYN NDC SAO LAI IMP

I

Supply–

Stabilizer

References

DC Mask Generation

AC Termination

2–4 Wire Conversion

Line Length AGC

Protection

C12

Line +

Line –

26

27

25

6

7

1

21

22

8

2 3 4

10 11 14 9 13 20

Anti–Howling

Line
Driver

Ear

Mic

Mute, AGC

MC34216A

C17

AGC

28

ref

CC

Mute, AGC

CM

C16

12

To IMP To SAI

To IMP

Ring–

AGnd
5

RS
19

Clk
18

D/HS
17

Regulator

DTMF/Tone

and Ring

Generator

Micro–

Interface

Clock

Hook–Detect

Osc

16

X1

LPO

R30

LPI

23

24

LSP

C24

Volume

Microphone Threshold

C29C28C27C26

C25

To IMP

C21

R28

To

Micro–

controller

R1

SAI

15

Handset

Earpiece

Handset

Microphone

Speaker

Figure 2. Block Diagram of the MC34216A with Essential Components

DC CHARACTERISTICS AND STARTUP

2

1

3

4

VLC

IVLPILKILP

VLK

ILC

VLP

V

I

0

line

line

Region 1: Startup, Low Line Current, High Slope
Region 2: Mid Range Line Current, Small Slope

Region 3: High Line Current, High Slope
Region 4: Overload Protection

Figure 3. General Form of the

DC Mask of the MC34216A

The MC34216A offers the possibility to adjust the dc

characteristics of all 4 regions via both software and hardware

adjustments. The software adjustments make it possible to
program the 4 different basic masks: France, United Kingdom,
Low Voltage and Startup. The hardware adjustments can be
used for fine–tuning. The adjustment possibilities will be
discussed below with the aid of the block diagram of Figure 4.

In Region 1, the transfer of the amplifier G at the HYN input
equals zero. The voltage difference between SAO and SAI
will equal VO1. The slope RE1 of the V

line

, I

line

characteristic

will equal:

R

E1

+

R1 xǒ1

)

Z0

Z21

Ǔ

In Region 2, the output current of the amplifier G will be
proportional to the input current. As a result, the voltage
between SAO and SAI will increase with the line voltage.
Speech signals on the line are of no influence on this
because they are filtered out via capacitor C16. The slope
RE2 of the V

line

, I

line

characteristic will equal:

R

E2

+

R1 x

ȧ

ȡ
Ȣ

1

)

1
Ri
Z1

)

Z21

Z0

ȧ

ȣ
Ȥ

In Region 3, the output current of the amplifier G is kept
constant. As a result, the slope in Region 3 will equal the
slope of Region 1.

MC34216A

10

MOTOROLA ANALOG IC DEVICE DATA

Z21

T3

T2

Z1

C12

RX

Z0

R5

V

C7

2V 1.4 V

V

Line +

HYN

LAI

SAONDC

SAI

LAO

Line –

Gnd

I2

R1

MC34216A

C16

2.4 V

IMP

CM

G

CC

O2

BE

V

O1

+

+

+

+

+

+

≈

+

+

Figure 4. DC Part of the Block Diagram of the MC34216A

The transfer from Region 2 to 3 occurs at the point VLK,

ILK, which is calculated:

VLK+Z1 x I2CD)2VBE)

VCD)

V

O2

ILK

+

Z21

Z0

xǒZ1 x I2CD)2V

BE

Ǔ

)

V

CD

R1

With : I2CD

+

I2C)I2D

2

, and VCD+

VC)

V

D

2

,

and 2VBE[

1.4 V, VO2[

1.1 V

When the French or U.K. mask is selected, this transfer
takes place for line currents of 30 mA to 40 mA depending
on the components settings. With the Startup and Low
Voltage mask, the transfer lies outside the normal operating
range with line currents of 90 mA or more. In most
applications, the transfer from Region 1 to 2 takes place for
line currents below 10 mA.

With proper settings, Region 4 is only entered during an
overload condition. In this mode, the power consumption in
the telephone set is limited. In order to detect an overload
condition, the voltage between the Pins LAI and SAO is
monitored. When the voltage difference is larger than the
threshold V

clamp1

, the protection is made active. The relation

for the line voltage VLP at this point is given as:

VLP

+

Z0

Z21

x V

clamp1

)

VCD)

V

O2

When the protection mode is entered, the line current is

reduced to a lower value ILP of:

ILP

+

V

clamp2

)

ǒ

VO1– V

O2

Ǔ

R1

When the line voltage becomes smaller than VLP, the
overload condition is gone and the MC34216A will leave
Region 4.

The current drawn from the line by the dc part is used to
supply the MC34216A and peripheral circuits. The surplus of
current is sunk away by the voltage stabilizer at Pin V

CC

where a reservoir capacitor is connected. The reference for
the circuit is Pin Gnd.

Startup of the application is ensured by an internal startup
circuit. During the startup, the internal registers of the
MC34216A are reset, and the reset Pin RS goes high. This
signals is meant to indicate to the microcontroller that the
programming of the MC34216A can start.

When the line current flows, the hook status output
Pin D/HS goes high. This serves as the information for the
microcontroller that the set is off–hook. When the line current
is no longer present, the pin goes low again. Because the line
current is monitored, and not the line voltage, an interrupt of
the exchange can be recognized.

MC34216A

11

MOTOROLA ANALOG IC DEVICE DATA

AC CHARACTERISTICS

Impedance

In Figure 5, the block diagram of the MC34216A
performing the ac impedance is depicted. As can be seen, it
is partly in common with the dc mask block diagram. The part
generating the dc mask is replaced by a dc voltage source
because for ac, this part has no effect.

Z21

T3

T2

Z0

R5

V

C7

V

LAI

SAO

SAI

LAO

Gnd

R1

MC34216A

CC

O2

V

O1

Line +

Line –

+

+

+

+

Figure 5. AC Stage of the MC34216A

When calculating the ac loop, it can be derived that the set
impedance Zin equals:

Z

in

+

V

line

I

line

+

R1ǒ1

)

Z0

Z21

Ǔ

[

R1 x

Z0

Z21

As can be noticed, the formula for the ac impedance Z

in

equals the formula for the dc slope in Regions 1 and 3.
However, because for the dc slopes the resistive part of Z0
and Z21 are used, the actual values for Zin and the dc slopes
do not have to be equal.

A complex impedance can be made by making either Z0
or Z21 complex. When Z0 is made complex to fit the set
impedance, the transmit characteristics will be complex as
well. The complex impedance is therefore preferably made
via the Z21 network. Because Z21 is in the denominator of
the Zin formula, Z21 will not be a direct copy of the required
impedance, but a derivative of it. Figure 6 shows the derived
network to be used for Z21.

Cb

Ra

Rb

Rv Rv

Rw

Cw

SAO LAI

Gnd

Rv

+

R1 x Z0

2(Ra)Rb – R1

)

Rw

+

R1 x Z0(Ra – R1

)

4Rb(Ra)Rb – R1

)

Cw

+

4Rb

2

x Cb

R1 x Z0

Figure 6. Derived Network for Z21 in Case

of Complex Set Impedance

Transmit

When on Pin LAI a current is injected, via the loop
depicted in Figure 5, a signal is created on the line. In this
way, the microphone signals and DTMF signals from the
internal generator are transmitted. It can be derived that the
signal voltage on the line (V

line

) depends on the signal

current injected in LAI (I

LAI

) according to:

V

line

+

–I

LAI

x

Z0 x Z

line

Zin)

Z

line

With this relation, a simplified replacement circuit can be
made for the transmit amplifier (see Figure 7). Here the
product of I

LAI

and Z0 is replaced by one voltage source.

Z

+

–

line

Z

in

V

line

–I

LAI

*Z0

+

Figure 7. Replacement Diagram for the

Transmit Amplifier

The microphone signal current is derived from the
microphone signal according to the schematic in Figure 8.

Ru

Cmic

Cu

R

MIC

TXI

Microphone

Handset

Ku

Line AGC

Iu

MC34216A

Microphone Threshold

V

CC

R

I

LAI

TXI

Mic

Figure 8. Microphone Amplifier Input Stage

The input stage in Figure 8 consists of a current amplifier
with transfer Ku and impedance R

TXI

= 1.0 kΩ plus an
attenuator which reduces the signal current at high line
currents, the so–called line length regulated gain or line AGC.
This attenuator can be switched on/off via the microcontroller.
The input current Iu within the telephony speech band is
derived from the microphone signal according to:

Iu

+

Vu

R

Mic

)Ru)

R

TXI

[

Vu
Ru

With: Vu = signal of the microphone only loaded with R

Mic

.

The overall gain from microphone to line (ATX) now follows

as:

ATX+

V

line

Vu

+

Ku

Ru

x

Z0 x Z

line

Zin)

Z

line

Practically, the gain can only be varied with Z0, Ru and

R

Mic

.

MC34216A

12

MOTOROLA ANALOG IC DEVICE DATA

2.4 V

2V

C17

R20

Z1

R1

RXO2

–1 X

IMP

HYN

RXO1

SAI

Handset
Earpiece

C

Line AGC

V

Line +

Line –

RXI

Gnd

MC34216A

BE

+ V

O1

ref

load

R

load

G

C

ear

e

+

+

+

+

Figure 9. Receive Part of the MC34216A

The noise which is transmitted to the line can be reduced
when the microphone threshold feature is enabled. This is
also called squelch. When there is no microphone signal
present, the transmit gain is reduced by 7.0 dB with respect
to nominal. In between, the gain is varied in steps of 1.0 dB
dependent on the signal level. The detection of the
microphone signal level is done via an integrator which uses
the external capacitors C28 and C29 for timing and filtering.
This feature is also very useful to reduce the howling effect
during listening–in.

The MC34216A offers the possibility to mute the
microphone, also called privacy mode. In this case, the far
end user no longer hears the local user. It is possible to send
during this mode an idle tone to the line to make the far end
user aware of this.

During pulse–dialing, the microphone biasing can be
switched off by programming. Pin Mic will then be made high
impedance, meaning that the microphone dc current no
longer flows into this pin. This reduces the current
consumption of the application during pulse–dialing. It can
also be used to disconnect the handset microphone signal
and enable another transmit signal, for instance from a
handsfree microphone.

Receive

The receive portion of the MC34216A is shown in Figure 9.

The receive signal is picked up by the amplifier at the HYN
input. This is the same amplifier as present in the dc loop of
Figure 4. The signal is first converted to current by the
transconductance amplifier with transfer Ge. The multiplier
placed after performs line length dependent gain or line AGC.
Afterwards, the current is converted back to voltage via the
external feedback network Z

load

. The resulting voltage is
available at output RXO1, and at RXO2 which is the inverted
earpiece output.

From the diagram of Figure 9 the receive gain (ARX) can

be derived as:

With :

A

RX

+

V

RXO

V

line

+

Gex R1 x Z

load

x

ǒ

1

Z

h

)

1

Z

in

Ǔ

Zh+

R1 x Z1

R20

,

also see the sidetone characteristics below.

The earpiece can either be connected as a single–ended
or as a bridge–tied load. The above calculated gain is valid
for the single–ended case. When connecting as a bridge–tied
load, the gain is increased by 6.0 dB.

The MC34216A offers the possibility to increase the
receive gain to the earpiece with an extra 6.0 dB via the
microcontroller on command of the user of the telephone set.
This is useful for people with hearing problems or when the
far end user speaks very softly.

The MC34216A offers the possibility to mute the signal
coming from the line to the earpiece. This is useful during
pulse–dialing or to mute the far end user.

Sidetone

When a transmit signal is transmitted to the line, a part of
the signal is returned to the receive channel due to the nature
of the 2 to 4 wire conversion of the hybrid. During transmit,
the signal on the line will be –I

line

x Z

line

. During receive, the

signal on the line will be I

line

x Zin. When replacing Zin in the
formula for the receive gain, it follows that the signal on the
earpiece output due to a sending signal on the line will be:

V

ear

V

line–transmit

+

Gex R1 x Z

load

x

ǒ

1

Z

h

–

1

Z

line

Ǔ

The sidetone can be minimized by making Zh equal to

Z

line

. A complex sidetone network can therefore be made via
a complex Z1. The coupling capacitor C17 in series with R20
is only meant to block dc.

Line Length AGC

The MC34216A offers the possibility to vary the transmit
and receive gains over line length in order to compensate for
the loss in gain at longer line lengths. In the block diagrams
of the transmit and receive channels the attenuator
performing the line AGC is already drawn. The line AGC can
be switched on/off via the microcontroller. In case the line
AGC is switched off, the transmit and receive gain are
lowered 2.0 dB with respect to the value calculated via the
formulas above.

The line AGC characteristics for both transmit and receive
channels have the general shape depicted in Figure 10.

MC34216A

13

MOTOROLA ANALOG IC DEVICE DATA

ILIL

Reduced

Gain

Nominal

Gain

Gain

I

Gain

+

Nominal Gain

1

)

IL – IL

start

IL

range

range

line

start

Figure 10. General Line AGC Characteristics

For small line currents, and thus long lines, the gains are

nominal. When the line current has increased above IL

start

with a current IL

range

, the gain is reduced by 6.0 dB. Due to
the general characteristics of the line AGC curve, the gain will
be decreased further for higher currents.

For France and the U.K., the line AGC will be active in

Region 3 of the dc characteristics. The IL

start

is approximately

equal to the ILK. The range is determined by:

IL

range

+

Z1 x(I2R – I2CD

)

R

E3

For Low Voltage mask, the line AGC is active in Region 2.

Loudspeaking Facility

The MC34216A incorporates a loudspeaking facility which
facilitates group listening–in with incorporated anti–howling
circuitry, handsfree conversation with external duplex
controller and ringing via loudspeaker with external switched
mode power supply.

Loudspeaker Amplifier

The block diagram of the loudspeaker amplifier which is
incorporated in the MC34216A is depicted in Figure 11.

The first part of the loudspeaker amplifier equals the
receive part of the earphone amplifier. It therefore also
includes the anti sidetone circuit and the line current AGC.
The overall gain from line to loudspeaker output LPO is
therefore:

A

LSP

+

ǒ

1

)

R30
R28

Ǔ

x RTx Gex R1 x

ǒ

1

Z

h

)

1

Z

in

Ǔ

The gain of the loudspeaker amplifier can be adjusted by
the external components as indicated in the formula above.
However, the gain is also influenced by line length AGC,
volume control and the signal limiter AGC.

The influence of line length AGC on the loudspeaker
channel is equal to its influence on the receive amplifier of the
earpiece because it is in their common path.

The volume of the loudspeaker is controlled via the
microcontroller. In total, 8 levels can be programmed: 7 levels
with equal steps of 4.5 dB and one level which completely
mutes the loudspeaker amplifier.

The output signal is limited by an AGC circuit when the
peaks of the signal are larger than a certain threshold (peak
AGC) and when the line current available is not sufficient
(current AGC). This prevents distortion of the output signal
and a drop of the supply voltage VCC.

Listening–In

During group listening–in, both the handset and the
loudspeaker are active. Via the acoustic coupling from
loudspeaker to handset microphone, howling can occur
when the handset is held close to the base. In order to reduce
howling, an anti–howling correlator and a microphone
threshold are incorporated in the MC34216A. Both functions
can be switched on/off via the microcontroller.

The anti–howling correlator monitors the microphone and
loudspeaker signal via capacitors C26 through C29. When
both signals show a high correlation, then both contain a
common signal. In practice, this means that howling is
present. In this case, the anti–howling correlator will reduce
the loudspeaker gain in steps of 1.25 dB, until the correlation
is below a certain threshold.

C24

2.4 V

2V

C17

R20

Z1

R1

IMP

HYN

SAI

C23

Line AGC

Line +

Line –

Gnd

MC34216A

BE

+ V

O1

R30

Anti–
Howl

I

VolumeMicrophone

Threshold

LPO

Signal
Limiter

C25 C21

LPI

ACG

R

R28

Loudspeaker

Control

RX

T

+

+

+

Figure 11. Block Diagram of the Loudspeaker Amplifier

MC34216A

14

MOTOROLA ANALOG IC DEVICE DATA

The microphone threshold reduces the gain in the acoustic
feedback loop by 7.0 dB. When there is no, or only a small
microphone signal, the gain in the transmit path is reduced by

7.0 dB with respect to nominal. The loudspeaker gain is then
at its nominal value. At a high microphone input current, the
microphone gain is back to its nominal value and the
loudspeaker gain reduced by 7.0 dB. The behavior of the
microphone threshold feature is depicted in Figure 12.

33 n 110 n

A

A

Gain

Iu (Arms)

Nominal

Reduced

TX

LSP

Figure 12. Behavior of the Microphone

Threshold Feature

Handsfree

A speakerphone application for handsfree conversation
can easily be made with the MC34216A by adding one of
the Motorola speakerphone cores to it. The TXI input can be
used to amplify the transmit signal and the earphone output
can be used to monitor the receive signal. The receive
output of the speakerphone core can be connected to
AHO1. When programming the MC34216A in speakerphone

mode, the signal on this pin will be amplified to the
loudspeaker output. In this way, the features and
functionality of the MC34216A are optimally used, like its
powerful supply, loudspeaker amplifier with anti–distortion
circuitry and line current regulation. More details about this
application can be found in the user manual.

Ringing

The MC34216A offers the possibility to generate a ringing
melody via the loudspeaker, which avoids the use of a piezo
buzzer. The power needed to supply the loudspeaker is
transformed out of the ringer signal by a switched mode
power supply TCA3385. The melody is generated by the
MC34216A and programmed via the microcontroller. This
concept is depicted in Figure 13.

As can be seen in Figure 13, the high voltage ring signal is
first transformed into a low voltage supply point with high
current capability. This is needed because, compared to a
piezo resonator, a loudspeaker is low ohmic. In the ringing
mode, the voltage of the supply point is stabilized by the
MC34216A to 5.5 V . The ringing melody can be programmed
via the microcontroller and is generated internally. The output
signal level is regulated via a gain control loop. The loop
couples the value of VCC to the output current of the ringing
melody generator. No ringing melody is made audible when
VCC is below 3.8 V and the maximum volume is reached
when VCC has reached 5.5 V.

To ensure optimum output power under low line current
conditions, the current consumption of the MC34216A in
ringing mode is reduced down to 2.0 mA.

The MC34216A offers the possibility to listen to the ringing
melody while in the speech mode. Although the feeding
conditions are not equal for ringing and speech mode, this
offers the user the possibility to program his own melody and
to adjust the volume.

Hookswitch

R4 C4

Bus

C8

R24

T1

L1

D10

R30

R1

C24

RDO

Gnd

R

LI

Ringer
Supply

Regulator

and Melody

Generator

Micro-

controller

LPI

LPO

Gnd

Off Hook

Application

I

SAI of
MC34216A

TCA3385

MC34216A

CO

DRV

V

C7

CC

V

CC

Phone Line

R

in

Figure 13. Concept of Ringing Via Loudspeaker

MC34216A

15

MOTOROLA ANALOG IC DEVICE DATA

Programming Possibilities

The MC34216A can be programmed by a microcontroller
via a 2 wire bus. In this way, it is possible to program the dc
mask, DTMF tones, listening–in mode, loudspeaker volume,
etc.

The bus interface of the microcontroller with the
MC34216A consists of 2 wires: a data wire and a clock wire
connected to Pins D/HS and CLK respectively. Also, the
reset Pin RST of the MC34216A is connected to the
microcontroller. The MC34216A itself has a local oscillator
connected to Pin Osc.

The local oscillator needs a 500 kHz parallel mode
ceramic resonator, with approximately 75 pF capacitance,
connected to ground (for instance, the TOKO
FCRK500A–P35). The local oscillator is the reference for all
the internal timings of the MC34216A.

The 2 wire bus is based on the SCI standard. This
standard includes things such as de–bouncing and bus
monitoring in order to check that the data is sent over
correctly. The full bus specification is depicted in Figure 14.
The data is read in during the falling edge of the clock signal.
The clock has to be active only during the transfer of the data.
After the data is sent, the clock has to be kept low.

The D/HS pin is not only the input for the data but also the
output for the hookswitch information. When there is line
current flowing, this pin will be high, provided that the clock
line is low.

The reset Pin RST of the MC34216A is high for supply
voltages on VCC of 3.1 V and higher. It is the indication for the
microcontroller that programming of the device is possible.
When RST becomes high and D/HS is high as well, the
microcontroller can start programming the registers for the
speech mode. When information from the ringer indicates
that there is a ring signal present on the line, the
microcontroller can start programming the registers for
ringing mode.

The registers of the MC34216A are 8–bits wide. The
register bits are shown in Figure 15. The 8–bits can be split
up into 2 address bits and 6 data bits of the format
A1A0D5D4D3D2D1D0. Data is sent over starting with the
address bits (A1 and A0) and then the data bits, D5 through
D0.

During startup of the MC34216A, the registers are
internally reset in order to have a defined state. The contents
of the registers after the reset are also given in Figure 15. In
summary, it starts up with LV mask and handset mode with
the transducers muted.

TI Tclk T(on)

TDS TDH

Clk

D/HS

T1

Clk

D/HS

Figure 14. Bus Specification

Symbol Description Min Max Unit

Tclk

Clock Period

125

1000

µs

Tclk
T(on)

Clock Period
High Level Duration

125661000–µs

µs

T(on)
TDS

High Level Duration
Data Setup Time

6610–

Tonµsµs

TDS
TDH

Data Setup Time
Data Hold Time

1020Ton

900µsµs

TDHTDData Hold Time
Debounce Time

2016900–µs
µs

TDTIDebounce Time
Data Reset Time to First Clock Rising Edge

1640––µs
µs

TIT1Data Reset Time to First Clock Rising Edge
Interval Between 2 Successive 8–Bit Words

40

700––µsµs

T1
Vihc

Interval Between 2 Successive 8–Bit Words
High Input Level – Clock

700

0.7–5.0µsVdc

Vihc
Vilc

High Input Level – Clock
Low Input Level – Clock

0.7

0.0

5.0

0.3

Vdc
Vdc

Vilc
Vihd

Low Input Level – Clock
High Input Level – Data

0.0

1.7

0.3

5.0

Vdc
Vdc

Vild Low Input Level – Data 0.0 1.2 Vdc

MC34216A

16

MOTOROLA ANALOG IC DEVICE DATA

Figure 15. Register Description

Address

Data

Symbol

Function

БББББББ

БББББББ

БББББББ

State at Reset

A1, A0 = 00

D0

MicM

Microphone Mute

БББББББ

БББББББ

БББББББ

0 = Muted

D1

EM

Earphone Mute

БББББББ

БББББББ

БББББББ

0 = Muted

D2

LD

Loop Disconnect

БББББББ

БББББББ

БББББББ

0 = Loop Closed

D3

PT

Pilot Tone

БББББББ

БББББББ

БББББББ

0 = Tone “Off”

D4

IT

Idle Tone

БББББББ

БББББББ

БББББББ

0 = Tone “Off”

D5

MicP

Microphone Power

БББББББ

БББББББ

БББББББ

0 = Power “Off”

A1, A0 = 01

D0

MFC0

Tone Control

БББББББ

БББББББ

БББББББ

0, See Tables Below

D1

MFC1

Tone Control

БББББББ

БББББББ

БББББББ

0, See Tables Below

D2

MF0

Tone Select

БББББББ

БББББББ

БББББББ

0, See Tables Below

D3

MF1

Tone Select

БББББББ

БББББББ

БББББББ

0, See Tables Below

D4

MF2

Tone Select

БББББББ

БББББББ

БББББББ

0, See Tables Below

D5

MF3

Tone Select

БББББББ

БББББББ

БББББББ

0, See Tables Below

A1, A0 = 10

D0

R/S

Ring/Speech Mode

БББББББ

БББББББ

БББББББ

0 = Speech Mode

D1

EA

Earphone Gain 6.0 dB

БББББББ

БББББББ

БББББББ

0 = Nominal Gain

D2

G0

Loudspeaker Gain

БББББББ

БББББББ

БББББББ

0, See Tables Below

D3

G1

Loudspeaker Gain

БББББББ

БББББББ

БББББББ

0, See Tables Below

D4

G2

Loudspeaker Gain

БББББББ

БББББББ

БББББББ

0, See Tables Below

D5

RT

Ring Tone

БББББББ

БББББББ

БББББББ

0 = Tone “Off”

A1, A0 = 11

D0

DCM0

DC Mask Control

БББББББ

БББББББ

БББББББ

0, See Tables Below

D1

DCM1

DC Mask Control

БББББББ

БББББББ

БББББББ

1, See Tables Below

D2

Sp

Speakerphone Mode

БББББББ

БББББББ

БББББББ

0 = “Off”

D3

GR

Line Length Regulation

БББББББ

БББББББ

БББББББ

0 = “On”

D4

HPI

Anti–Howling

БББББББ

БББББББ

БББББББ

0 = “On”

D5

M

th

Microphone Threshold

БББББББ

БББББББ

БББББББ

0 = “On”

MFC1

MFC0

Function

0

0

Switch DTMF Generation “Off”

0

1

Select DTMF–Pair and Generate

1

0

Select Pilot/Idle/Ring Tone Frequency

1

1

Select DTMF/Idle Tone Level (Level I

LAI

)

DCM1

DCM0

Function

0

0

Startup Mask for France

0

1

U.K. Mask

1

0

Low Voltage Mask

1

1

French Mask

ÁÁÁ

ÁÁÁ

ÁÁÁ

G2

G1

G0

Function

ÁÁÁ

ÁÁÁ

ÁÁÁ

0

0

0

Loudspeaker Amplifier Muted

ÁÁÁ

ÁÁÁ

ÁÁÁ

0

0

1

Gain Reduction 27.0 dB

ÁÁÁ

ÁÁÁ

ÁÁÁ

0

1

0

Gain Reduction 22.5 dB

ÁÁÁ

ÁÁÁ

ÁÁÁ

0

1

1

Gain Reduction 18.0 dB

ÁÁÁ

ÁÁÁ

ÁÁÁ

1

0

0

Gain Reduction 13.5 dB

ÁÁÁ

ÁÁÁ

ÁÁÁ

1

0

1

Gain Reduction 9.0 dB

ÁÁÁ

ÁÁÁ

ÁÁÁ

1

1

0

Gain Reduction 4.5 dB

ÁÁÁ

ÁÁÁ

ÁÁÁ

1

1

1

No Attenuation, Nominal Gain

MC34216A

17

MOTOROLA ANALOG IC DEVICE DATA

Figure 16. Register Description

MFC1 = 0, MFC0 = 1

MFC1 = 1, MFC0 = 0

DTMF–Pair (in Hz)

MF3

MF2

MF1

MF0

Low

High

Key

Single Tone

(in Hz)

0

0

0

0

941

1633

D

440

0

0

0

1

941

1477

#

494

0

0

1

0

941

1336

0

523

0

0

1

1

941

1209

*

554

0

1

0

0

852

1633

C

587

0

1

0

1

852

1477

9

622

0

1

1

0

852

1336

8

659

0

1

1

1

852

1209

7

698

1

0

0

0

770

1633

B

784

1

0

0

1

770

1477

6

880

1

0

1

0

770

1336

5

988

1

0

1

1

770

1209

4

1047

1

1

0

0

697

1633

A

1319

1

1

0

1

697

1477

3

1661

1

1

1

0

697

1336

2

1760

1

1

1

1

697

1209

1

2093

The dc mask of the MC34216A can be programmed to fit
the different country requirements. During startup, this will be
the first register which has to be programmed in order to have
a dc setting as soon as possible.

The pulse–dialing is timed by the microcontroller
(make/brake ratio, inter–digit pause) by making the LD bit
high and low. Also, memory dialing or last number redial can
be done. During LD = 1, the MC34216A makes its output
LAO low for the line break and reduces its internal current
consumption. The current through the microphone can be
stopped also by making bit MicP low.

The transmit path can be muted by making the MicM bit
low. It effectively mutes both the signal from the handset
microphone as well as the signal coming from a
speakerphone circuit. During this microphone mute state, a

melody can be sent to the line (melody on hold). In order to
enable the idle tone function, the IT bit has to be made high.
The squelch function can be enabled by making the Mth bit
low. The line AGC feature can be enabled by making the
GR bit low.

The receive path can be muted by making the EM bit low.
It effectively mutes both the signal from the line to the
handset earpiece as well as to the loudspeaker output.
During this mute state, a pilot tone melody can be sent to the
earpiece or loudspeaker. This is very useful during
pulse–dialing, programming of telephone numbers in
memories or during operation of an answering or fax
machine. In order to enable the pilot tone function, the PT bit
has to be made high. The gain of the earphone amplifier can
be increased by 6.0 dB by making the EA bit high.

MC34216A

18

MOTOROLA ANALOG IC DEVICE DATA

The MC34216A incorporates a DTMF generator with
integrated filters. The DTMF pairs can be selected by the
microcontroller via the MF bits. In this way, the whole DTMF
range for a 4x4 keyboard is available which fulfills the CCITT
requirements. The DTMF level on the line can be adjusted
by external components and it can also be programmed via
the MF bits.

For listening–in operation, the loudspeaker has to be
switched on and the anti–howling circuitry has to be
activated. The loudspeaker is switched on by making the
G2G1G0 bits high. They also set the volume. The
anti–howling circuit is activated by making bit HPI low. By
making bit Mth high, the microphone threshold feature is
enabled which further reduces the effect of howling.

By making the SP bit high, the speakerphone mode is
programmed. This automatically disables the earpiece by
muting the RXO2 output, and it enables the AHO1 input as a
speakerphone signal input. By making the MicP bit low, the
handset microphone is no longer powered and is thus muted.
This ensures that only the signal from the base microphone is
transmitted to the line.

By making the R/S bit high, the ringing mode is
programmed. The ringing melody is programmed via the
microcontroller and generated by the MC34216A. The
volume can be programmed via the 3 loudspeaker gain bits
G2G1G0. The ring melody is enabled by making the ring
tone switch RT high. The melody can be tested during
normal speech mode by activating the ring tone switch R

T

while R/S is low.

The answering machine mode is entered by making the
R/S bit high. This enables the microphone, earphone and
loudspeaker amplifiers while the set is on–hook. This makes

it possible to record a message with the handset microphone
and to playback messages via the earpiece or loudspeaker.
Other blocks of the circuit are not activated. During off–hook
operation, the incoming messages can be recorded and the
outgoing message can be played in the normal way. More
details about the answering machine application can be
found in the user manual.

Support Material

Device Specification: Brief description of the MC34216A,

block diagram, device data, bus
specification, test diagram, typical
application

User Manual MC34216A: Extended description of the circuit

and its concept, description of the
programmability, adjustment
procedure, application hints and
proposals

Demonstration Board: Performance of the MC34216A is

shown in an application with the
TCA3385 switched mode power
supply and a MC68HC705
microcontroller

Adjustment Software: A QBASIC program which helps

the customer to find the right
component values for fulfilling the
requirements

Register Display Board: Visualizes the register contents

which are transmitted on the
demonstration board by means of
LEDs

MC34216A

19

MOTOROLA ANALOG IC DEVICE DATA

6

Line +

To IMP To SAI

R13

R16

R12

C16 C12

R21

R20

C17

To IMP

T2

HYN CM NDC SAO LAI IMP I

RXO1

C20

V

C7

R6

RXO2

AGnd

RXI

Gnd

R9

C5

TXI

T3

LAO

Mic

RS

To Microcontroller

Clk

D/HS

R1

C30

R15

C11

C14

To HYN

C13

C32

C31

R5

C2

R31

R7

From

V

26

27

25

7

21

5

22

8

19

18

17

14 9 13 2010 12 11

Line –

C35

C3

C19

C34

LPO LPI

23 24

R29

C22

C21

R28

C23

R30

C24

C6

C25

AGC

28

AHO1 AHO2 MTF MTC SAI Osc

X1

C26 C27 C28 C29

To IMP

1 2 3 4 15 16

MC34216A

R14 C10

Component

Value

LV

Value

F

Value

U.K. Component

Value

LV

Value

F

Value

U.K. Component

Value

LV, F, U.K.

R1 20 15 15 C2 470 p C22 100 n

R5 820 C3 220 p C23 330 p

R6 150 k C5 10 n C24 47

R7 1.0 k C6 22 n C25 220 n

R9 39 k C7 470 C26 220 n

R12 69.8 k C10 0 4.7 n 330 p C27 220 n

R13 560 k 560 k 330 k C11 220 p 470 p 470 p C28 15 n

R14 0 620 k 620 k C12 10 n 1.0 n 10 n C29 100 n

R15 750 k 620 k 620 k C13 470 p C30 10

R16 150 k 120 k 120 k C14 470 p C31 100 n

R20 7.5 k 5.1 k 13 k C16 470 n C32 1.0 n

R21 20 k 16.2 k 15 k C17 680 n C34 4.7 n

R28 10 k C19 100 n C35 2.2

R29 10 C20 10 T2 MJE350

R30 220 k C21 68 n T3 MPSA42

R31 1.8 k X1 500 kHz

Figure 17. Typical Application

µ

µ

µ

µ

CC

ref

CC

µ

+

+

LV = Low Voltage Mode

F = France

U.K. = United Kingdom

Handset

Earpiece

Handset

Microphone

Speaker

MC34216A

20

MOTOROLA ANALOG IC DEVICE DATA

DW, DWF SUFFIX

PLASTIC PACKAGE

CASE 751F–04

ISSUE E

OUTLINE DIMENSIONS

MIN MINMAX MAX

MILLIMETERS INCHES

DIM

A
B
C
D
F
G
J
K
M
P
R

17.80

7.40

2.35

0.35

0.41

0.23

0.13
0

°

10.05

0.25

18.05

7.60

2.65

0.49

0.90

0.32

0.29
8

°

10.55

0.75

0.701

0.292

0.093

0.014

0.016

0.009

0.005
0

°

0.395

0.010

0.711

0.299

0.104

0.019

0.035

0.013

0.011
8

°

0.415

0.029

1.27 BSC 0.050 BSC

NOTES:

1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.

2. CONTROLLING DIMENSION: MILLIMETER.

3. DIMENSION A AND B DO NOT INCLUDE MOLD
PROTRUSION.

4. MAXIMUM MOLD PROTRUSION 0.15
(0.006) PER SIDE.

5. DIMENSION D DOES NOT INCLUDE
DAMBAR PROTRUSION.

ALLOWABLE
DAMBAR PROTRUSION SHALL BE 0.13
(0.005) TOTAL IN EXCESS OF D
DIMENSION AT MAXIMUM MATERIAL
CONDITION.

-A-

-B-

1 14

1528

-T-

C

SEATING
PLANE

0.010 (0.25)

B

M M

M

J

-T-

K

26X G

28X D

14X P

R

X 45°

F

0.010 (0.25) T A B

M

S S

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the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit,
and specifically disclaims any and all liability, including without limitation consequential or incidental damages. “T ypical” parameters can and do vary in different
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MC34216A/D

*MC34216A/D*

◊