Philips TEA1064A-C2, TEA1064A-C1, TEA1064AT-C2, TEA1064AT-C1 Datasheet

INTEGRATED CIRCUITS

DATA SHEET

TEA1064A

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

Product specification			March 1994
File under Integrated Circuits, IC03A

Philips Semiconductors	Product specification

Low voltage versatile telephone transmission circuit

TEA1064A

with dialler interface and transmit level dynamic limiting

GENERAL DESCRIPTION

The TEA1064A 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 and has a powerful DC supply for peripheral circuits. 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.

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 in two options: unregulated supply, regulated line voltage;

stabilized supply, line voltage varies with supply current

∙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 magnetic, dynamic 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

PACKAGE OUTLINES

TEA1064A :20-lead DIL; plastic (SOT146).(1)

TEA1064AT:20-lead mini-pack; plastic (SO20; SOT163A).(2)

Notes

1.SOT146-1; 1998 Jun 18.

2.SOT163-1; 1998 Jun 18.

March 1994

2

Philips Semiconductors	Product specification

Low voltage versatile telephone transmission circuit

TEA1064A

with dialler interface and transmit level dynamic limiting

		VCC1						LN
		16						1
	13							6	GAR
IR
								5
						−	+		QR+
			TEA1064A
						+	−	4	QR−
								19	VCC2
	9							2
MIC+				+					GAS1
MIC−	8			−		−
				+		+
	12							3
DTMF			dB						GAS2
				−
MUTE	14
PD	15	SUPPLY AND
		REFERENCE
					AGC	LOW
						VOLTAGE
					CIRCUIT
						CIRCUIT	DYNAMIC
							LIMITER
					CURRENT	START
					REFERENCE	CIRCUIT
		11	17	18	10		7	20
		VEE	REG	AGC	STAB		DLS/MMUTE	SLPE	MGR056

Fig.1 Block diagram.

March 1994

3

Philips Semiconductors	Product specification

Low voltage versatile telephone transmission circuit

TEA1064A

with dialler interface and transmit level dynamic limiting

QUICK REFERENCE DATA

PARAMETER	CONDITIONS	SYMBOL	MIN.	TYP.	MAX.	UNIT
Operating ambient temperature
range		Tamb	−25	−	+ 75	°C
Line current operating range:
normal operation		l	11	−	140(1)	mA
		line
with reduced performance		lline	2	−	11	mA
Internal supply current:
power-down input LOW	VCC1 = 2.8 V	ICC1	−	1.3	1.6	mA
power-down input HIGH	VCC1 = 2.8 V	ICC1	−	60	82	μA
Voltage gain range:
microphone amplifier		Gv	44	−	52	dB
receiving amplifier		Gv	20	−	45	dB
Line loss compensation:
gain control range		Gv	5.7	6.1	6.5	dB
exchange supply voltage
range		Vexch	36	−	60	V
exchange feeding bridge
resistance range		Rexch	400	−	1000	Ω
Maximum output voltage swing
on LN (peak-to-peak value)	R15 + R16 = 448 Ω
	lline = 15 mA
	Ip = 2 mA	VLN(p-p)	3.7	3.95	4.2	V
	Ip = 4 mA	VLN(p-p)	3.0	3.25	3.5	V
Regulated line voltage application
	R15 = 0 Ω;
	R16 = 392 Ω
Supply for peripherals	lline = 15 mA
	Ip = 1.4 mA	Vp	2.5	−	−	V
	Ip = 2.7 mA;
	RREG-SLPE = 20 kΩ	Vp	2.9	−	−	V
DC line voltage	lline = 15 mA
	without RREG-SLPE	VLN	−	3.57	−	V
	RREG-SLPE = 20 kΩ	VLN	−	4.57	−	V

March 1994

4

Philips Semiconductors	Product specification

Low voltage versatile telephone transmission circuit

TEA1064A

with dialler interface and transmit level dynamic limiting

PARAMETER		CONDITIONS	SYMBOL	MIN.	TYP.	MAX.	UNIT
Stabilized supply voltage application
	R15	= 392 Ω;
	R16	= 56 Ω
Supply for peripherals	lline = 15 mA
	Ip = 0 to 4 mA		VCC2-SLPE	3.05	3.3	3.55	V
DC line voltage	lline = 15 mA
	Ip = 2 mA		VLN	4.2	4.4	4.8	V
	Ip = 4 mA		VLN	4.9	5.1	5.5	V

Note

1. For TEA1064AT the maximum line current depends on the heat dissipating qualities of the mounted device.

PINNING

handbook, halfpage
	LN		1		20	SLPE
						VCC2
	GAS1		2		19
	GAS2		3		18	AGC
	QR−
			4		17	REG
	QR+					VCC1
			5		16
	GAR			TEA1064A		PD
			6		15
DLS/MMUTE			7		14	MUTE
	MIC−		8			IR
					13
	MIC+		9			DTMF
					12
	STAB 10					VEE
					11
				MGR057

Fig.2 Pinning diagram.

1	LN	positive line terminal
2	GAS1	gain adjustment; transmitting amplifier
3	GAS2	gain adjustment; transmitting amplifier
4	QR−	inverting output, receiving amplifier
5	QR+	non-inverting output, receiving
		amplifier
6	GAR	gain adjustment; receiving amplifier
7	DLS/	decoupling for transmit amplifier
	MMUTE	dynamic and microphone MUTE input
8	MIC−	inverting microphone input
9	MIC+	non-inverting microphone input
10	STAB	current stabilizer
11	VEE	negative line terminal
12	DTMF	dual-tone multi-frequency input
13	IR	receiving amplifier input
14	MUTE	mute input
15	PD	power-down input
16	VCC1	internal supply decoupling
17	REG	voltage regulator decoupling
18	AGC	automatic gain control input
19	VCC2	reference voltage with respect to SLPE
20	SLPE	slope adjustment for DC
		curve/reference for peripheral circuits.

March 1994

5

Philips Semiconductors	Product specification

Low voltage versatile telephone transmission circuit

TEA1064A

with dialler interface and transmit level dynamic limiting

FUNCTIONAL DESCRIPTION

Supplies VCC1, VCC2, LN, SLPE, REG and STAB (Fig.3)

Power for the TEA1064A and its peripheral circuits is usually obtained from the telephone line. The IC develops its own supply voltage at VCC1 and regulates its voltage drop. The internal supply requires a decoupling capacitor between VCC1 and VEE. The internal current stabilizer is set by a 3.6 kΩ resistor between STAB and VEE.

The DC current flowing into the set is determined by the exchange supply voltage Vexch, the feeding bridge

resistance Rexch, the subscriber line DC resistance Rline 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 VCC2 and SLPE

[Vref = VCC2-SLPE = 3.3 V (typ.)]. This internal voltage regulator requires decoupling by a capacitor between REG

and VEE (C3).

The reference voltage can be used to:

∙regulate directly the line voltage (stabilized

VLN-SLPE = VCC2-SLPE)(1)

∙to stabilize the supply voltage for peripherals.

Regulated line voltage

In this application the VCC2 pin is connected to the LN pin as shown in Fig.3. This configuration 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 independent of the line current and depends only on the peripheral supply current.

The value of R16 and the level of the DC voltage VLN-SLPE 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 DC

voltage VLN-SLPE can be increased by using RVA(REG-SLPE) or by decreasing the value of R16.

(1)The TEA1064A application with regulated line voltage is the same as is used for TEA1060/TEA1061, TEA1067 and TEA1068 integrated circuits.

handbook, full pagewidth

Ip + 0.25 mA

Rline

I

line

R1

ISLPE

ICC1

LN

VCC1

TEA1064A

1

16

V

Rexch

19

CC2

DC

0.25 mA

C1

R16

Vexch

AC

11

17

10

20

REG

STAB

SLPE

VEE

Ip

C3

R5

R9

C15

peripheral

Vp

circuits

MGR058

The voltage VLN-SLPE is fixed to Vref = 3.3 ± 0.25 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 VLN = Vref + ([Iline − 1.55 mA] × R9).

Fig.3 Application with regulated line voltage (stabilized VLN-SLPE).

March 1994

6

Philips Semiconductors	Product specification

Low voltage versatile telephone transmission circuit

TEA1064A

with dialler interface and transmit level dynamic limiting

5					MGR059
handbook, halfpage
Ip
(mA)
4
3		R
		VA
		(REG
2			-
			SLPE)
	R		=
	VA		20
1		without	k
			Ω
	(REG
		-
		SLPE)
0		3		4
2					Vp (V)

lline = 15 mA; R16 = 392 Ω; R15 = 0 Ω; valid for MUTE = 0 and 1. Line current has very little influence

Fig.4 Minimum supply current for peripherals (Ip) as a function of the peripheral supply voltage (Vp).

The maximum AC output swing on the line at low line currents is influenced by R16 (limited by current) and the maximum output swing on the line at high line currents is influenced by the DC voltage VLN-SLPE (limited by voltage). In both these situations, the internal dynamic limiter in the sending channel prevents distortion when the microphone input is overdriven. The maximum AC output swing on LN is shown in Fig.5; practical values for R16 are from 200 to 600 Ω and this influences both the maximum output swing at low line currents and the supply capabilities.

The SLPE pin is the ground reference for peripheral circuits, therefore inputs MUTE, PD and DTMF are also referenced to SLPE.

Active microphones can be supplied between VCC1 and VEE. Low-power circuits that provide only MUTE and/or PD inputs to the TEA1064A also can be powered from VCC1. However VCC1 cannot be used for circuits that provide DTMF signals to the TEA1064A because VCC1 is referred to ground.

If the line current lline exceeds ICC1 + 0.25 mA, the voltage converter shunts the excess current to SLPE via LN;

where ICC1 ≈ 1.3 mA, the value required by the IC for normal operation.

The DC line voltage on LN is:

VLN = VLN-SLPE + (ISLPE × R9)

VLN = Vref + ([Iline − ICC1 − 0.25 × 10−3 A] × R9)

in which

Vref = 3.3 V ± 0.25 V is the internal reference voltage

between VCC2 and SLPE; its value can be adjusted by external resistor RVA

R9 = external resistor between SLPE and VEE (20 Ω in basic application).

With R9 = 20 Ω, this results in:

VLN = 3.57 ± 0.25 V at lline = 15 mA

VLN = 4.17 ± 0.3 V at lline = 15 mA,

RVA(REG-SLPE) = 33 kΩ

VLN = 4.57 ± 0.35 V at lline = 15 mA,

RVA(REG-SLPE) = 20 kΩ

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, ISLPE >> (ICC1 + 0.25 mA) and the 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 the audio frequency range is shown in Fig.6.

The internal reference voltage VCC2-SLPE can be increased by external resistor RVA(REG-SLPE) connected between

REG and SLPE. The supply voltage VCC2-SLPE is shown as a function of RVA(REG-SLPE) in Fig.7. Changing the reference 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.

March 1994

7

Philips Semiconductors	Product specification

Low voltage versatile telephone transmission circuit

TEA1064A

with dialler interface and transmit level dynamic limiting

6			MGR060
VLN(p-p)			handbook, halfpage		LN
(V)
4			Leq	Rp	R1
			Vref	REG	VCC1
	Ip =		R9	C3
	0 mA				C1
2	2 mA		20 Ω	4.7 μF
	4 mA				VEE
					MGR061
0
10	20	Iline (mA)	30

Fig.6	Equivalent impedance between LN and
	VEE in the application with stabilized
Fig.5 Maximum AC output swing on the line as a	VLN-SLPE:
function of line current with peripheral	R15 = 0 Ω
supply current as a parameter: R15 = 0 Ω;	Leq = C3 × R9 × Rp
R16 = 392 Ω.	Rp = 15 kΩ

handbook, full pagewidth	7.8	MGR062

Vref

(V)

6.6

5.4

4.2

with RVA infinite

3.0

0	40	80	120
		RVA (REG-SLPE) (kΩ)

Fig.7 Internal reference voltage VCC2-SLPE as a function of resistor RVA(REG-SLPE) for line currents between 11 and 140 mA.

In the stabilized supply application:

VLN = VCC2-SLPE + ([Ip + 0.25 × 10−3 A] × R15) + ([Iline − 1.55 × 10−3 A] × R9)

In the unregulated supply application (R15 = 0 Ω):

VLN = VCC2-SLPE + ([Iline − 1.55 × 10−3 A] × R9)

March 1994

8

Philips Semiconductors	Product specification

Low voltage versatile telephone transmission circuit

TEA1064A

with dialler interface and transmit level dynamic limiting

Stabilized peripheral supply voltage

The configuration shown in Fig.8 provides a stabilized voltage across pins VCC2 and SLPE for peripheral circuits (such as dialling and control circuits); the DC voltage VLN now varies with the peripheral supply current.

The VCC2-SLPE supply must be decoupled by capacitor C15. For stable loop operation, resistor R16 (» 50 W) is

connected between VCC2 and SLPE in series with C15. The voltage regulator control loop is completed by resistor R15 between LN and VCC2.

For sets with an impedance of 600 W, practical values are: R15 = 200 to 600 W; C15 = 220 mF; C3 = 470 nF. The ratio R15/R16 £ 8 is for stable loop operation with sufficient phase margin, and R15/R16 ³ 6 is for satisfactory set impedance in the audio frequency range.

For sets with complex impedance, the value of C3 and the ratio R15/R16 are different (further information is given in the TEA1064A Application Report(1)).

The peripheral supply capability depends mainly on the available line current, the required AC output swing on the line, the maximum permitted DC voltage on the line and

the values of external components (especially R15). With R15 = 392 W and R16 = 56 W (basic application) the maximum possible AC output swing on the line as a function of line current is as shown in Fig.9, the curve parameter is the peripheral supply current (Ip). Different values for R15 (from 200 to 600 W) maintaining

6 < R15/R16 < 8 give different results (these are described in the TEA1064A Application Report (1).

(1) Supplied on request.

handbook, full pagewidth

R15

Ip + 0.25 mA

Rline

I

line

R1

ISLPE

ICC1

LN

VCC1

TEA1064A

1

16

V

Rexch

19

CC2

DC

0.25 mA

C1

R16

Vexch

AC

11

17

10

20

Ip

REG

STAB

SLPE

VEE

C3

R5

R9

C15

peripheral

Vp

circuits

MGR063

Fig.8 Application with stabilized supply voltage for peripheral circuits: R15 = 392 W; R16 = 56 W.

March 1994

9

Philips Semiconductors	Product specification

Low voltage versatile telephone transmission circuit

TEA1064A

with dialler interface and transmit level dynamic limiting

The DC line voltage on LN is

VLN = VLN-SLPE + (ISLPE × R9).

Therefore

VLN = Vref + ([Ip + 0.25 × 10-3 A] × R15) +

([lline − ICC1 − 0.25 × 10-3 A] × R9)

in which:

Vref is the internal reference voltage between VCC2 and SLPE (the value of Vref can be adjusted by an external resistor, RVA). Vref = 3.3 V (typ.) without RVA

Ip is the supply current used by peripheral circuits

R15 is an external resistor between LN and VCC2 (392 Ω in the basic application)

R9 is an external resistor between SLPE and VEE (20 Ω in the basic application)

8		MGR064
handbook, halfpage
VLN(p-p)		Ip = 4 mA
(V)
6		2 mA
4		0 mA
2
0
10	20	Iline (mA)	30

As different values of R15 and R16 are allowed, different curves would then apply

Fig.9 Maximum output swing on line as a function of line current with the peripheral supply current as a parameter; R15 = 392 Ω;

R16 = 56 Ω.

The DC voltage VLN-SLPE as a function of Ip with R15 as a parameter is shown in Fig.10. In the audio frequency

range, the dynamic impedance is determined mainly by R1. The equivalent impedance in the audio range of the circuit (Fig.8) is shown in Fig.11.

MGR065

5.5 handbook, halfpage

VLN-SLPE

(V)

5.0

R15 = 511 W

392 W

4.5

301 W

4.0

3.5

3.0

0

1

2

3

4

Ip (mA)

VCC2-SLPE can be adjusted between approximately 3.3 and 4.3 V by changing the value of RVA, this results in a parallel-shift of the curves.

The total voltage drop VLN » VLN-SLPE + ([Iline - 1.55 mA] ´ R9).

Fig.10 Curves showing the typical voltage drop between LN and SLPE as a function of the supply current for peripherals with R15 as a

parameter: VCC2-SLPE = 3.3 V (RVA not connected).

handbook, halfpage

LN

Leq

Req

R1

R9

C3

620 W

20 W

470 nF

VEE

MGR066

R

= R

æ R15

1

ö

eq

---------- +

ø

p è R16

Leq

= C3 ´ R9 ´ Req with Rp= 15 kW

Fig.11 Equivalent impedance between LN and VEE at f > 300 Hz in the application with stabilized supply voltage for peripheral circuits.

March 1994

10

Philips Semiconductors	Product specification

Low voltage versatile telephone transmission circuit

TEA1064A

with dialler interface and transmit level dynamic limiting

Microphone inputs MIC+ and MIC− and gain pins

GAS1 and GAS2

The TEA1064A has symmetrical microphone inputs, its input impedance is 64 kΩ (2 × 32 kΩ) and its voltage amplification is typ. 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.12.

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 × C6.

		VCC1
MIC+	MIC−	16	MIC+
9		8	9

(1)

MIC−	MIC+	MIC−
8	9	8
		11

VEE

MGR067

(a)

(b)

(c)

Fig.12 Microphone arrangements: a) magnetic or dynamic microphone, the 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; b) electret microphone; c) piezo-electric microphone.

Dynamic limiter (microphone) pin DLS/MMUTE

A low level at the DLS/MMUTE pin inhibits the microphone inputs MIC+ and MIC− but has no influence on the receiving and DTMF amplifiers.

Removing the low level at the DLS/MMUTE pin provides the normal function of the microphone amplifier after a short time determined by the capacitor connected to DLS/MMUTE pin. The microphone mute function can be realised by a simple switch as shown in Fig.13.

To prevent distortion of the transmitted signal, the gain of the sending amplifier is reduced rapidly when peaks of the signal on the line exceed an internally-determined threshold. The time in which gain reduction is effected (attack time) is very short. The circuit stays in the gain-reduced condition until the peaks of the sending signal remain below the threshold level. The sending gain then returns to normal after a time determined by the capacitor connected to DLS/MMUTE (release time).

The internal threshold adapts automatically to the DC voltage setting of the circuit (voltage VLN-SLPE). This

means that the maximum output swing on the line will be higher if the DC voltage dropped across the circuit is increased.

Fig.14 shows the maximum possible output swing on the

line as a function of the DC voltage drop (VLN-SLPE) with Iline − Ip as a parameter.

handbook, halfpage

DLS/MMUTE 7

R17

3.3 kΩ

VEE

11

MGR068

Fig.13 Microphone-mute function.

March 1994

11