Philips TEA1064BT Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TEA1064B

Low voltage versatile telephone
transmission circuit with dialler
interface and transmit level
dynamic limiting

Product specification
File under Integrated Circuits, IC03A

March 1994

Philips Semiconductors Product specification

Low voltage versatile telephone transmission circuit
with dialler interface and transmit level dynamic limiting

FEATURES

• Low DC line voltage; operates down to 1.8 V (excluding
polarity guard)

• Voltage regulator with low voltage drop and adjustable
static resistance

• DC line voltage adjustment facility

• Provides a supply for external circuits

• Dynamic limiting (speech-controlled) in transmit

direction prevents distortion of line signal and sidetone

• Symmetrical high-impedance inputs (64 kΩ) for
dynamic, magnetic or piezo-electric microphones

• Asymmetrical high-impedance input (32 kΩ) for electret
microphones

• DTMF signal input

• Confidence tone in the earpiece during DTMF dialling

• Mute input for disabling speech during pulse or DTMF

dialling

• Power-down input for improved performance during
pulse dial or register recall (flash)

• Receiving amplifier for dynamic, magnetic or
piezo-electric earpieces

• Large amplification setting ranges on microphone and
earpiece amplifiers

• Line loss compensation (line current dependent) for
microphone and earpiece amplifiers (not used for DTMF
amplifier)

• Gain control curve adaptable to exchange supply

• Automatic disabling of the DTMF amplifier in

extremely-low voltage conditions

• Microphone MUTE function available with switch

• MUTE, POWER-DOWN and DTMF input reference (pin

) can be connected either to V

V

EE2

GENERAL DESCRIPTION

The TEA1064B is a bipolar integrated circuit that performs
all the speech and line interface functions required in fully
electronic telephone sets. It performs electronic switching
between dialling and speech. The IC operates at line
voltages down to 1.8 V DC (with reduced performance) to
facilitate the use of more telephone sets connected in
parallel. The transmit signal on the line is dynamically
limited (speech-controlled) to prevent distortion at high
transmit levels of both the sending signal and the sidetone.

TEA1064B

or SLPE.

EE1

ORDERING INFORMATION

EXTENDED TYPE

NUMBER

TEA1064B 20 DIL plastic SOT146
TEA1064BT 20 mini-pack plastic SO20; SOT163A

Notes

1. SOT146-1; 1998 Jun 18.

2. SOT163-1; 1998 Jun 18.

PINS PIN POSITION MATERIAL CODE

PACKAGE

(1)

(2)

March 1994 2

Philips Semiconductors Product specification

Low voltage versatile telephone transmission circuit

TEA1064B

with dialler interface and transmit level dynamic limiting

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

I

line

I

CC

G

v

G

v

V

exch

R

exch

V

LN(p-p)

V

p

V

LN

T

amb

line current operating range

normal operation note 1 11 − 140 mA
with reduced performance 2 − 11 mA

internal supply current VCC = 2.8 V

power-down input LOW − 1.3 1.6 mA
power-down input HIGH − 60 82 µA

voltage gain range

microphone amplifier 44 − 52 dB
receiving amplifier 20 − 45 dB

line loss compensation ranges

gain control 5.7 6.1 6.5 dB
exchange supply voltage 36 − 60 V
exchange feeding bridge resistance 400 − 1000 Ω

maximum output voltage swing on LN
(peak-to-peak value)

supply for peripherals I

DC line voltage I

R16 = 392 Ω;
I

= 15 mA

line

I

= 1.4 mA 3.55 3.80 4.05 V

p

= 2.7 mA 3.25 3.50 3.75 V

I

p

= 15 mA

line

= 1.4 mA 2.5 2.7 − V

I

p

I

= 2.7 mA;

p

R

REG-SLPE

= 15 mA

line

without R
R

REG-SLPE

= 20 kΩ

REG-SLPE

= 20 kΩ 4.05 4.4 4.75 V

2.9 3.1 − V

3.25 3.5 3.75 V

operating ambient temperature range −25 −+75 °C

Note

1. For the TEA1064BT the maximum line current depends on the heat dissipating qualities of the mounted device.

March 1994 3

Philips Semiconductors Product specification

Low voltage versatile telephone transmission circuit
with dialler interface and transmit level dynamic limiting

13

9
8

12

14

15

V

CC

TEA1064B

dB

SUPPLY AND
REFERENCE

−
+

+

−

+

−
+

−

handbook, full pagewidth

IR

MIC+
MIC−

DTMF

MUTE

PD

TEA1064B

LN

116

6

GAR

5

+

−

QR+

4

QR−

2

GAS1

3

GAS2

V

EE1VEE2

AGC

CIRCUIT

CURRENT

REFERENCE

171911

18 10 7 20

REG AGC STAB

Fig.1 Block diagram.

LOW

VOLTAGE

CIRCUIT

START

CIRCUIT

DYNAMIC

LIMITER

DLS/MMUTE

SLPE

MBA442

March 1994 4

Philips Semiconductors Product specification

Low voltage versatile telephone transmission circuit
with dialler interface and transmit level dynamic limiting

PINNING

SYMBOL PIN DESCRIPTION

LN 1 positive line terminal
GAS1 2 gain adjustment; transmitting amplifier
GAS2 3 gain adjustment; transmitting amplifier
QR− 4 inverting output; receiving amplifier
QR+ 5 non-inverting output; receiving amplifier
GAR 6 gain adjustment; receiving amplifier
DLS/

MMUTE 7 decoupling for transmit amplifier dynamic and microphone MUTE input
MIC− 8 inverting microphone input
MIC+ 9 non-inverting microphone input
STAB 10 current stabilizer
V

EE1

DTMF 12 dual-tone multi-frequency input
IR 13 receiving amplifier input
MUTE 14 mute input
PD 15 power-down input
V

CC

REG 17 voltage regulator decoupling
AGC 18 automatic gain control input
V

EE2

SLPE 20 slope adjustment for DC curve/reference for peripheral circuits

11 negative line terminal

16 internal supply decoupling

19 reference for POWER-DOWN (PD), MUTE and DTMF

TEA1064B

handbook, halfpage

DLS/MMUTE

LN
GAS1
GAS2

QR−
QR+

GAR

MIC−
MIC+

STAB

1
2
3
4
5

TEA1064B

6
7
8
9

10

Fig.2 Pin configuration.

March 1994 5

MBA433

20

SLPE
V

19

EE2

18

AGC

17

REG
V

16

CC

15

PD
MUTE

14

IR

13

DTMF

12

V

11

EE1

Philips Semiconductors Product specification

Low voltage versatile telephone transmission circuit
with dialler interface and transmit level dynamic limiting

FUNCTIONAL DESCRIPTION

, V

Supplies V

CC

, LN, SLPE, REG and STAB (Figs 3

EE2

and 5)

Power for the TEA1064B and its peripheral circuits is
usually obtained from the telephone line. The IC develops
its own supply voltage at V

and regulates its voltage

CC

drop. The internal supply requires a decoupling capacitor
between VCC and V
set by a 3.6 kΩ resistor between STAB and V

. The internal current stabilizer is

EE1

EE1

.

The DC current flowing into the set is determined by the
exchange supply voltage V
resistance R

, the subscriber line DC resistance R

exch

, the feeding bridge

exch

line

and the DC voltage (including polarity guard) on the
subscriber set (see Fig.3).

The internal voltage regulator generates a
temperature-compensated reference voltage that is
available between LN and SLPE (V

ref

= V

LN-SLPE

= 3.23 V
typ.). This internal voltage regulator requires decoupling
by a capacitor between REG and V

EE1

(C3).

The configuration shown in Fig.3, gives a stabilized
voltage across pins LN and SLPE which, applied via the
low-pass filter R16, C15, provides a supply to the
peripherals that is independant of the line current and
depends only on the peripheral supply current.

The value of R16 and the level of the DC voltage V
determine the supply capabilities. In the basic application
R16 = 392 Ω and C15 = 220 µF. The worst-case
peripheral supply current as a function of supply voltage is
shown in Fig.4.

To increase the supply capabilities, the value of R16 can
be decreased or the DC voltage V
by using R

VA(REG-SLPE)

Note

The TEA1064B application is the same as is used for
TEA1060/TEA1061, TEA1067 and TEA1068 integrated
circuits.

TEA1064B

LN-SLPE

can be increased

LN-SLPE

.

I

CC

Ip + 0.25 mA

V

CC

16

0.25 mA

11

19

V

V

EE1

EE2

handbook, full pagewidth

R

line

R

exch

V

exch

The voltage V
Resistor R16 together with the line current determine the supply capabilities and the maximum output swing on
the line (no loop damping is necessary).
The line voltage V

LN-SLPE

LN=Vref

is fixed to V

+ ({I

= 3.323 ±0.25 V.

ref

− 1.55 mA}× R9).

line

I

line

I

SLPE

TEA1064B

DC
AC

17
REG

C3 R5

+ 0.25 mA

10
STAB20SLPE

R1

LN
1

R9

Fig.3 Supply arrangement with reference to SLPE.

R16C1

C15

peripheral

circuits

MBA435

I

p

V

p

March 1994 6

Philips Semiconductors Product specification

Low voltage versatile telephone transmission circuit
with dialler interface and transmit level dynamic limiting

MBA436

Vp (V)

handbook, halfpage

(mA)

I

= 15 mA; R16 = 392 Ω; valid for MUTE = 0 and 1.

line

Line current has very little influence.

5

I

p

4

3

2

1

0

2345

R

VA(REG-SLPE)

R

VA(REG-SLPE)

without

= 20 kΩ

TEA1064B

Fig.4 Maximum supply current with respect to Fig.3 for peripherals (Ip) as a function of the peripheral supply

voltage (Vp).

I

SLPE

I

line

+ 0.25 mA

STAB

R1

I

CC

LN
116

20

SLPE

V

CC

0.25 mA

11

EE1

V

EE2

C1

peripheral

circuits

MBA432

I

p

handbook, full pagewidth

V

R

exch

exch

R

line

TEA1064B

DC
AC

17 10 19
REG V

C3 R5 R9

Fig.5 Supply arrangement with reference to V

March 1994 7

EE1

.

Philips Semiconductors Product specification

Low voltage versatile telephone transmission circuit
with dialler interface and transmit level dynamic limiting

VCC). MUTE, PD and DTMF are then referenced to V

= 20 kΩ

3

VCC (V)

MBA434

2.4

handbook, halfpage

I

p

(mA)

1.6

0.8

0

(a) Ip= 1.94 mA

= 1.54 mA

(b) I

p

= 0.54 mA

(a′) I

p

= 0.16 mA

(b′)I

p

=15mA

I

line

R1 = 620 Ω and R9 = 20 Ω
Curve (a) and (a′) are valid when the receiving
amplifier is not driven or when MUTE = HIGH.
Curve (b) and (b′) are valid when the receiving
amplifier is driven and when MUTE = LOW.
V

o(RMS)

(a)

(b)

R

VA(REG-SLPE)

(a')

(b')

012 4

= 150 mV, RT= 150 Ω.

R
VA(REG-SLPE)

without

Fig.6 Maximum current Ipwith respect to Fig.5

available from Vccfor peripheral circuitry
with VCC> 2.2 V.

The maximum AC output swing on the line at low currents
is influenced by R16 (limited by current) and the maximum
output swing on the line at high currents is influenced by
DC voltage V

(limited by voltage). In both these

LN-SLPE

situations, the internal dynamic limiter in the sending
channel prevents distortion when the microphone is
overdriven. The maximum AC output swing on LN is
shown in Fig.7; practical values for R16 are from 200 Ω to
600 Ω and this influences both maximum output swing at
low line currents and the supply capabilities.

When the SLPE pin is the reference for peripheral circuits,
inputs MUTE, PD and DTMF must be referenced to SLPE.
This is achieved by connecting pin V

to pin SLPE; V

EE2

EE2

being the reference of MUTE, PD and DTMF input stages.
Active microphones can be supplied between VCC and

V

as shown in Fig.5. Low power circuits that provide

EE1

MUTE, PD and DTMF inputs to the TEA1064B can also be
powered from VCC (see Fig.6 for the supply capability of

and the pin V
If the line current I

converter shunts the excess current to SLPE via LN;
where ICC≈ 1.3 mA, the value required by the IC for
normal operation.

The DC line voltage on LN is:

• VLN = V

• VLN = V

in which:

• V

= 3.23 V ± 0.25 V is the internal reference voltage

ref

between LN and SLPE; its value can be adjusted by
external resistor RVA.

• R9 = external resistor between SLPE and V
basic operation).

With R9 = 20 Ω, this results in:

• VLN = 3.3 ± 0.25 V at I

• VLN = 4.1 ± 0.3 V at I

• VLN = 4.4 ± 0.35 V at I

R

VA(REG- SLPE)

The preferred value for R9 is 20 Ω. Changing R9
influences microphone gain, DTMF gain, the gain control
characteristics, sidetone and the DC characteristics
(especially the low voltage characteristics).

In normal conditions, I
static behaviour is equivalent to a voltage regulator diode
with an internal resistance of R9. In the audio frequency
range the dynamic impedance is determined mainly by R1.
The equivalent impedance of the circuit in audio frequency
range is shown in Fig.8.

The internal reference voltage V
by external resistor R
REG and SLPE. The voltage V
function of R
voltage influences the output swing of both sending and
receiving amplifiers.

At line currents below 8 mA (typ.), the DC voltage dropped
across the circuit is adjusted to a lower level automatically
(approximately 1.8 V at 2 mA). This gives the possibility of
operating more telephone sets in parallel with DC line
voltages (excluding polarity guard) down to an absolute
minimum of 1.8 V. At line currents below 8 mA (typ.), the
circuit has limited sending and receiving levels.

must therefore be connected to V

EE2

LN-SLPE

+ ({I

ref

line

VA(REG-SLPE)

TEA1064B

exceeds ICC+ 0.25 mA, the voltage

line

+ (I

x R9)

SLPE

− ICC− 0.25 x 10−3 A} x R9)

= 15 mA

line

= 15 mA, R

line

line

= 15mA,

VA(REG-SLPE)

= 20 kΩ

>> (ICC+ 0.25 mA) and the

SLPE

can be increased

LN-SLPE

VA(REG-SLPE)

connected between

is shown as a

LN-SLPE

in Fig.9. Changing the reference

EE1

EE1

.

EE1

(20 Ω in

= 33 kΩ

March 1994 8

Philips Semiconductors Product specification

Low voltage versatile telephone transmission circuit
with dialler interface and transmit level dynamic limiting

(mA)

MBA437

handbook, halfpage

L

V

R9
20 Ω

Leq=C3×R9 × R
Rp=15kΩ

p

Fig.8 Equivalent impedance between LN and

VEE.

handbook, halfpage

6

V

LN(p-p)

(V)

4

Ip =

2

0

10

R16 = 392 Ω; Ipwith respect to Fig.3.

0 mA

1.4 mA

2.7 mA

20 30

I

line

Fig.7 Typical AC output swing at total harmonic

distortion (THD) = 2% on the line as a
function of line current with peripheral
supply current as a parameter.

TEA1064B

LN

eq

ref

R

p

REG

C3

4.7 µF

R1

V

C1

MBA438

CC

V

EE1

handbook, full pagewidth

VLN=V

LN-SLPE

+ ({I

− 1.55 × 10−3A} × R9).

line

Fig.9 Internal reference voltage V

and 140 mA.

7.8

V

ref

(V)

6.6

5.4

4.2

3.0
08040 120

LN-SLPE

as a function of resistor R

RVVA (REG-SLPE) (kΩ)

MBA467

VA(REG-SLPE)

with R

VA

infinite

for line currents between 11 mA

March 1994 9

Philips Semiconductors Product specification

Low voltage versatile telephone transmission circuit
with dialler interface and transmit level dynamic limiting

Microphone inputs MIC+ and MIC− and gain pins
GAS1 and GAS2

The TEA1064B has symmetrical microphone inputs, its
input impedance is 64 kΩ (2 x 32 kΩ) and its voltage
amplification is typically 52 dB with R7 = 68 kΩ. Either
dynamic, magnetic or piezo-electric microphones can be
used, or an electret microphone with a built-in FET buffer.
Arrangements for the microphone types are shown in
Fig.10.

handbook, full pagewidth

MIC+

9

(1)

MIC−

8

The gain of the microphone amplifier is proportional to
external resistor R7 connected between GAS1 and GAS2
and with this it can be adjusted between 44 dB and
52 dB to suit the sensitivity of the transducer.

An external 100 pF capacitor (C6) is required between
GAS1 and SLPE to ensure stability. A larger value of C6
may be chosen to obtain a first-order low-pass filter with a
cut-off frequency corresponding to the time constant
R7 x C6.

V

CC

MIC−

MIC+

16

8

9

11

V

EE1

TEA1064B

MIC+

9

MIC−

8

MBA439

(a) (b)

Resistor (1) may be connected to reduce the terminating impedance, or for sensitive types a resistive attenuator
can be used to prevent overloading the microphone inputs.

(c)

Fig.10 Microphone arrangements (a) magnetic or dynamic microphone (b) electret microphone (c) piezo-electric

microphone currents.

March 1994 10