Philips UBA1707TS-C2, UBA1707TS-C1, UBA1707T-C2, UBA1707T-C1 Datasheet

DATA SH EET

Product speciﬁcation Supersedes data of 1998 Jun 11 File under Integrated Circuits, IC03

1999 Feb 17

INTEGRATED CIRCUITS

UBA1707

Cordless telephone, answering machine line interface

1999 Feb 17 2

Philips Semiconductors Product speciﬁcation

Cordless telephone, answering machine line interface

UBA1707

FEATURES Line interface

• Low DC line voltage; operates down to 1.2 V (excluding polarity guard)

• Voltage regulator with adjustable DC voltage

• DC mask for voltage or current regulation (CTR 21)

• Line current limitation for protection

• Electronic hook switch control input

• Transmit amplifier with:

– Symmetrical inputs – Fixed gain – Large signals handling capability.

• Receive amplifier with fixed gain

• Transmit and receive amplifiers AGC for line loss

compensation.

Auxiliary ampliﬁer

• Fixed gain.

Loudspeaker channel

• Dual inputs

• Rail-to-rail output stage for single-ended load drive

• High output current capability

• Dynamic limiter to prevent distortion

• Digital volume control

• Fixed maximum gain.

General purpose switches

• Three switches with open-collector.

3-wires serial bus interface

Allows to control:

• DC mask (voltage or current regulation)

• Receive amplifier mute function

• AGC:

– On/off – Slope –I

start

line current.

• Auxiliary amplifier mute function

• Loudspeaker channel:

– Input selection – Volume setting – Dynamic limiter inhibition – Power-down mode.

• General purpose switches state

• Global power-down mode.

Supply

Operates with external supply voltage from 3.0 to 5.5 V.

APPLICATIONS

• Cordless base stations

• Answering machines

• Mains or battery-powered telephone sets.

GENERAL DESCRIPTION

The UBA1707 is a BiCMOS integrated circuit intended for use in mains-powered telecom terminals. It performs all speech and line interface functions, DC mask for voltage or current regulation and electronic hook switch control. The device includes an auxiliary amplifier, a loudspeaker channel and general purpose switches.

Most of the characteristics are programmable via a 3-wire serial bus interface.

ORDERING INFORMATION

TYPE

NUMBER

PACKAGE

NAME DESCRIPTION VERSION

UBA1707T SO28 plastic small outline package; 28 leads; body width 7.5 mm SOT136-1 UBA1707TS SSOP28 plastic shrink small outline package; 28 leads; body width 5.3 mm SOT341-1

1999 Feb 17 3

Philips Semiconductors Product speciﬁcation

Cordless telephone, answering machine line interface

UBA1707

QUICK REFERENCE DATA

line

= 15 mA; VCC= 3.3 V; R

SLPE

=10Ω; AGC pin connected to GND; Z

line

= 600 Ω; Z

SET

= 619 Ω; EHI = HIGH;

f = 1 kHz; T

amb

=25°C; bit AGC at logic 1, all other conﬁguration bits at logic 0; measured in test circuit of Fig.17;

unless otherwise speciﬁed.

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

operating voltage range 3.0 − 5.5 V

current consumption from pin V

normal operation; bit PD = 0 − 2.2 3.2 mA power-down mode; bit PD = 1 − 110 150 µA

line

line current operating range normal operation 11 − 140 mA

with reduced performance 3 − 11 mA

DC line voltage 2.7 3.0 3.3 V

REGC

DC mask slope in current regulation mode

line

> 35 mA (typical);

LVI

=1MΩ; R

RGL

= 7.15 kΩ;

bit CRC = 1

− 1.4 − kΩ

v(trx)

voltage gain

transmit amplifier from TXI to LN V

TXI

= 50 mV (RMS) 10.6 11.6 12.6 dB

receive amplifier from RXI to RXO V

RXI

= 2 mV (RMS) 36.9 37.9 38.9 dB

∆G

v(trx)

gain control range for transmit and receive ampliﬁers with respect to I

line

=15mA

line

=90mA − 6.5 − dB

v(AX)

voltage gain from AXI to AXO V

AXI

= 2 mV (RMS) 30.8 31.8 32.8 dB

v(LSA)

voltage gain from LSAI1 or LSAI2 to LSAO for maximum volume

LSAI

= 8 mV (RMS);

bits LSA1 = 1 and LSA2 = 1

26.5 28 29.5 dB

∆G

v(LSA)

voltage gain adjustment range for loudspeaker channel

bits (VOL0, VOL1, VOL2) from (0, 0, 0) to (1, 1, 1)

− 21 − dB

∆G

v(LSA)s

voltage gain adjustment step for loudspeaker channel

VOL0 from 0 to 1 − 3 − dB

1999 Feb 17 4

Philips Semiconductors Product speciﬁcation

Cordless telephone, answering machine line interface

UBA1707

BLOCK DIAGRAM

Fig.1 Block diagram.

Bit names are given in italics.

handbook, full pagewidth

MGK705

SERIAL

INTERFACE

EN CLK DATA

13 14 12

SUPPLY

GENERAL SWITCHES

SWI1 SWI2 SWI3

21 20

REG

LSAI1

LSAI2

LSPD

SWC1, SWC2, SWC3

VOL0 TO VOL2

LSA2

LSA1

0.5V

DYNAMIC LIMITER

VOLUME CONTROL

DLCI

DLC

LSAO

LSPGND 23

LOUDSPEAKER CHANNEL

AXI

AXO

LVI

RGL

AGC

TXI−

TXI+

RXI

AUXILIARY AMPLIFIER

LINE INTERFACE

UBA1707

AXM

CRC

RAGC1

SAGC, AGC

RAGC2

RXM

EHI

SLPE

600 mV

300 mV

AGC

LOW VOLTAGE

PART

CURRENT

LIMITATION

200 nA

CST

LCC

EHI

REG

SLPE

RXO

GND

CST

LVI

DARL

ON-HOOK

LN −

LN +

SLPE

SET

REG

RGL

1999 Feb 17 5

Philips Semiconductors Product speciﬁcation

Cordless telephone, answering machine line interface

UBA1707

PINNING

SYMBOL PIN DESCRIPTION

SLPE 1 connection for slope resistor LN 2 positive line terminal REG 3 line voltage regulator decoupling LVI 4 negative line voltage sense input RGL 5 reference for current regulation mode LCC 6 line current control output CST 7 input for stability capacitor RXO 8 receive ampliﬁer output AGC 9 automatic gain control/line loss

compensation adjustment RXI 10 receiver ampliﬁer input EHI 11 electronic hook switch control input DATA 12 serial bus data input EN 13 programming serial bus enable input CLK 14 serial bus clock input AXI 15 auxiliary ampliﬁer input AXO 16 auxiliary ampliﬁer output TXI− 17 inverted transmit ampliﬁer input TXI+ 18 non-inverted transmit ampliﬁer input SWI3 19 NPN open-collector output 3 SWI2 20 NPN open-collector output 2 SWI1 21 NPN open-collector output 1 GND 22 ground reference LSPGND 23 ground reference for the loudspeaker

ampliﬁer LSAO 24 loudspeaker ampliﬁer output V

25 supply voltage LSAI1 26 loudspeaker ampliﬁer input 1 LSAI2 27 loudspeaker ampliﬁer input 2 DLC 28 dynamic limiter timing adjustment

Fig.2 Pin configuration.

handbook, halfpage

SLPE

REG

LVI RGL LCC CST

RXO AGC

RXI EHI

DATA

CLK

DLC LSAI2 LSAI1 V

LSPGND GND

LSAO

SWI1 SWI2 SWI3 TXI+ TXI− AXO AXI

1 2 3 4 5 6 7 8

9 10 11 12 13

28 27 26 25 24 23 22 21

20 19 18 17 16 1514

UBA1707

MGK704

1999 Feb 17 6

Philips Semiconductors Product speciﬁcation

Cordless telephone, answering machine line interface

UBA1707

FUNCTIONAL DESCRIPTION

All data given in this chapter are typical values, except when otherwise specified.

Supply (pins V

and GND; bits PD and LSPD)

The UBA1707 must be supplied with an external stabilized voltage source between pins V

and GND. Pins GND and LSPGND must be connected together. Without any signal, with the loudspeaker channel enabled

at minimum volume and without any general purpose switch selected, the internal current consumption is

2.2 mA at VCC= 3.3 V. Each selected switch (pins SWI1, SWI2, or SWI3) increases the current consumption by 600 µA.

The supply current can be reduced when the loudspeaker channel is not used by switching it off (bit LSPD at logic 1). The current consumption is then decreased by approximately 800 µA at minimum volume.

To drastically reduce current consumption, the UBA1707 is provided with a power-down mode controlled by bit PD. When bit PD is at logic 1, the current consumption from VCC becomes 110 µA. In this mode, the serial interface is the only function which remains active.

Line interface

CHARACTERISTICS (PINS LN, SLPE, REG, CST, LVI,

LCC, RGL

AND GND; BIT CRC)

The IC generates a stabilized reference voltage (V

ref

) between pins LN and SLPE. This reference voltage is equal to 2.9 V, is temperature compensated and can be adjusted by means of an external resistor (RVA). It can be increased by connecting the RVA resistor between pins REG and SLPE (see Fig.3).

The voltage at pin REG is used by the internal regulator to generate the stabilized reference voltage and is decoupled by a capacitor (C

REG

) which is connected to GND. This capacitor, converted into an equivalent inductance (see Section “Set impedance”) realizes the set impedance conversion from its DC value (R

SLPE

) to its AC value

SET

in the audio-frequency range). Figure 4 illustrates the reference voltage supply configuration. As can be seen from Fig.4, part of the line current flows into the Z

SET

impedance network and is not sensed by the UBA1707. Therefore using the RVA resistor to change value of the reference voltage will also modify all parameters related to the line current such as:

• The automatic gain control

• The DC mask management

• The low voltage area characteristics.

In the same way, changing the value of Z

SET

also affects the characteristics. The IC has been optimized for V

ref

= 2.9 V and Z

SET

= 619 Ω.

The IC regulates the line voltage at pin LN which can be calculated as follows:

Where:

line

= line current

ZSET

= current flowing through Z

SET

I* = current consumed between LN and GND (approximately 100 µA).

The preferred value for R

SLPE

is 10 Ω. Changing R

SLPE

will affect more than the DC characteristics; it also influences the transmit gain, the gain control characteristics, the sidetone level and the maximum output swing on the line. However, for compliance with CTR 21 8.66 Ω is the best value for R

SLPE

Fig.3 Reference voltage adjustment with RVA.

(1) Influence of RVA on V

ref

(2) V

ref

without influence of RVA.

handbook, halfpage

8.5

2.5

(1)

(2)

MGK706

3.5

4.5

6.5

5.5

7.5

ref

(V)

RVA (Ω)

refRSLPEISLPE

×+=

SLPEIlineIZSET

I* I

lineIZSET

–≅––=

1999 Feb 17 7

Philips Semiconductors Product speciﬁcation

Cordless telephone, answering machine line interface

UBA1707

Fig.4 Reference voltage supply configuration.

handbook, full pagewidth

MGK707

35 kΩ

4 kΩ

REG

4.7 µF

SLPE

10 Ω

REG GNDSLPE

ZSET

SET

619 Ω

line

LN+

UBA1707

Fig.5 Line current settling simplified configuration.

handbook, full pagewidth

MGK708

35 kΩ

4 kΩ

REG

4.7 µF

SLPE

10 Ω

REG GND LCC EHISLPE

SET

619 Ω

ZSET

exch

EHI

ref

(TNSW)

line

LN+

LN−

UBA1707

HOOK SWITCH MANAGEMENT

1999 Feb 17 8

Philips Semiconductors Product speciﬁcation

Cordless telephone, answering machine line interface

UBA1707

The DC line current flowing into the set is determined by the exchange supply voltage (V

exch

), the feeding bridge

resistance (R

exch

), the DC resistors of the telephone line

line

) and the set (R

SET

), the reference voltage (V

ref

) and the voltage introduced by the transistor (TNSW) used as line interrupter (see Fig.5). With a line current below I

low

(8 mA with Z

SET

= 619 Ω), the internal reference voltage

ref

) is automatically adjusted to a lower value. This means that more sets can operate in parallel with DC line voltages (excluding the polarity guard) down to 1.2 V. At line current below I

low

, the circuit has limited transmit

and receive levels. This is called the low voltage area. Figure 6 shows in more details how the UBA1707, in

association with some external components, manages the line interrupter (TNSWexternal transistor).

In on-hook conditions (voltage at pin EHI is LOW), the voltage at pin LCC is pulled-up to the supply voltage level (VCC) to turn off the TP

DARL

transistor. As a result, because

of the R

PLD

resistor, the TNSWand TN

ON-HOOK

transistors

are switched off. The TN

ON-HOOK

transistor disconnects

the R

LVI

resistor from the LN− line terminal in order to

guarantee a high on-hook impedance.

In off-hook conditions (voltage at pin EHI is HIGH), an operational amplifier drives (at pin LCC) the base of TP

DARL

which forms a current amplifier structure in association with TNSW. The line current flows through TNSW transistor. The TN

ON-HOOK

transistor is forced into deep saturation. A virtual ground is created at pin LVI because of the operational amplifier. A DC current (I

LVI

) is

sourced from pin LVI into the R

LVI

resistor in order to generate a voltage source. Thus the voltage between pin GND and the negative line terminal (LN−) becomes:

VCE (TNSW)=R

LVI

× I

LVI+VCE

(TN

ON-HOOK

) ≅ R

LVI

× I

LVI

The voltage V

line

between the line terminals LN+ and LN−

can be calculated as follows: V

line

≅ V

ref+RSLPE

× (I

line

− I

ZSET

)+VCE(TNSW)

Where:

line

= line current

ZSET

= current flowing through Z

SET

1999 Feb 17 9

Philips Semiconductors Product speciﬁcation

Cordless telephone, answering machine

line interface

UBA1707

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ndbook, full pagewidth

MGK709

CURRENT

REGULATION

MODE

MANAGEMENT

LVIV

200 nA

EHI

REG

4.7 µF

LVI

PLU

150 kΩ

DARL

CRC

RGL

7.15 kΩ

LVI

470 pF

ON-HOOK

PROT

PLD

20 kΩ

ON-HOOK

100 kΩ

CST

22 pF

GNDLVIRGL CST

LCC

SLPE

8.2 V

line

LN−

4 kΩ

35 kΩ

REG

EHI

UBA1707

LN+

ref

SLPE

line

ZSET

SET

619 Ω

SLPE

10 Ω

LVI

1 MΩ

CURRENT

LIMITATION

Fig.6 Line interrupter management and DC mask regulation configuration.

Bit names are given in italics.

1999 Feb 17 10

Philips Semiconductors Product speciﬁcation

Cordless telephone, answering machine line interface

UBA1707

The UBA1707 offers the possibility to choose two kinds of regulations for the DC characteristic between the line terminals LN+ and LN− (see Fig.7):

• Voltage regulation mode

• Current regulation mode.

The regulation mode is selected by the bit CRC via the serial interface.

The DC mask regulation is realised by adjusting the DC voltage V

(TNSW) between pin GND and line terminal

LN− as a function of the line current.

Voltage regulation mode

In voltage regulation mode (bit CRC at logic 0), VCE(TNSW) voltage is fixed by means of a 200 nA DC constant current I

LVIV

flowing through R

LVI

Fig.7 General form of the DC mask as a function

of regulation mode.

(1) Low voltage area. (2) Small slope (determined by R

SLPE

(3) Small slope (dashed line; determined by R

SLPE

) in voltage

regulation mode. High slope (full line; determined by R

SLPE

, R

LVI

and R

RGL

) in

current regulation mode.

(4) Current limitation.

handbook, halfpage

MGK710

line

prot

(4)

knee

low

(1) (2) (3)

Therefore VCE(TNSW) ≅ R

LVI

× I

LVIV

= 200 mV in typical

application (see Fig.18). The slope ∆V

line

/∆I

line

of the V

line

, I

line

characteristic is

REGV

≅ R

SLPE.

Current regulation mode

In current regulation mode (bit CRC at logic 1), when the line current is lower than I

knee

= 35 mA (with

SET

= 619 Ω), VCE(TNSW) is fixed by means of a 200 nA

DC constant current I

LVIV

flowing through R

LVI

. When the line current is higher than 35 mA, an additional current (proportional to the line current) flows through R

LVI

. As a

result, TN

works as a DC voltage source increasing with

the line current. V

(TNSW) can be calculated as follows:

Where:

line

= line current

RGL

= resistor connected at pin RGL.

The slope ∆V

line

/∆I

line

of the V

line

, I

line

characteristic is determined by the ratio of resistors connected at pins SLPE, LVI and RGL, and can be calculated as

follows: in typical application (see Fig.18).

Current limitation

Whatever the selected mode is, the line current is limited to approximately 145 mA. This current is sensed on SLPE, for this purpose the external zener diode must be connected between pins LN and SLPE. The speech function no longer operates in this condition.

LECTRONIC HOOK SWITCH CONTROL (PIN EHI)

The electronic hook switch input (EHI) controls the state of TP

DARL

transistor. When the voltage applied at pin EHI is

LOW, TP

DARL

transistor is turned off. Voltage at pin LCC is

pulled up to supply voltage (VCC). TNSWand TN

ON-HOOK

transistors are also turned off by means of a pull-down resistor (R

PLD

). When the voltage applied at pin EHI is

HIGH, TP

DARL

transistor is driven by the operational amplifier at pin LCC and the regulation mode selected is operating. An internal 165 kΩ pull-up resistor is connected between pins LCC and VCC.

CETNSW

()R

LVI

SLPE

RGL

--------------- -

lineIknee

–()I

LVIV

+×







×≅

REGCRSLPERLVI

SLPE

RGL

--------------- -

1400 Ω=×+≅

1999 Feb 17 11

Philips Semiconductors Product speciﬁcation

Cordless telephone, answering machine line interface

UBA1707

The EHI input can also be used for pulse dialling or register recall (timed loop break). During line breaks (voltage at pin EHI is LOW or open-circuit), the voltage regulator is switched off and the capacitor at pin REG is internally disconnected to prevent its discharge. As a result, the voltage stabilizer will have negligible switch-on delay after line interruptions. This minimizes the contribution of the IC to the current waveform during pulse dialling or register recall.

When the UBA1707 is in power-down mode (bit PD at logic 1), the TP

DARL

transistor is forced to be turned off

whatever the voltage applied at pin EHI.

ET IMPEDANCE

In the audio frequency range, the dynamic impedance between pins LN and GND (illustrated in Fig.8) is mainly determined by the Z

SET

impedance.

The impedance introduced by the external TNSW transistor connected between pin GND and the negative line terminal (LN−) is negligible.

Fig.8 Equivalent impedance between

LN and GND.

Leq=C

REG

× R

SLPE

× R

RP= internal resistance = 35 kΩ.

handbook, halfpage

GND

SLPE

REG

SET

4.7 µF

619 Ω

10 Ω

ref

MGL215

TRANSMIT AMPLIFIER (PINS TXI+ AND TXI−) The UBA1707 has symmetrical transmit inputs TXI+ and

TXI−. The input impedance between pins TXI+ or TXI− and GND is 21 kΩ. The voltage gain from pins TXI+ or TXI− to pin LN is set at 11.6 dB with 600 Ω line load (Z

line

) and 619 Ω set impedance. The inputs are biased at 2 × Vd≅ 1.4 V, with Vd representing the diode voltage. Automatic gain control is provided on this amplifier for line loss compensation.

ECEIVE AMPLIFIER (PINS RXI AND RXO; BIT RXM)

The receive amplifier (see Fig.9) has one input (RXI) and one output (RXO). The input impedance between pins RXI and GND is 21 kΩ. The rail-to-rail output stage is designed to drive a 500 µA peak current. The output impedance at pin RXO is approximately 100 Ω.

The voltage gain from pin RXI to pin RXO is set at 37.9 dB. This gain value compensates typically the attenuation of the anti-sidetone network (see Fig.10). The output as well as the input are biased at 2 × Vd≅ 1.4 V. Automatic gain control is provided on this amplifier for line loss compensation. This amplifier can be muted by activating the receive mute function (bit RXM at logic 1).

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