Philips UBA1706TS Datasheet

INTEGRATED CIRCUITS

DATA SH EET

UBA1706

Cordless telephone line interface

Objective speciﬁcation Supersedes data of 1999 Mar 08 File under Integrated Circuits, IC17

1999 Jun 04

Philips Semiconductors Objective speciﬁcation

Cordless telephone line interface UBA1706

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 (CTR21)

• Line current limitation for protection

• Electronic hook switch control input

• Transmit amplifier with:

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

• Receive amplifier with fixed gain

• Transmit and receive amplifiers Automatic Gain Control

(AGC) for line loss compensation.

General purpose switches

Two switches with open-collector.

3-wire serial bus interface

APPLICATIONS

• Cordless base stations

• Mains or battery-powered telephone sets.

GENERAL DESCRIPTION

The UBA1706 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 also includes general purpose switches.

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

Allows control of:

• DC mask (voltage or current regulation)

• Receive amplifier mute function

• AGC:

– On/off – Slope –I

line current.

start

• The state of the general purpose switches

• Global power-down mode.

Supply

Operates with external supply voltage from 3.0 to 5.5 V.

ORDERING INFORMATION

TYPE

NUMBER

UBA1706TS SSOP24 plastic shrink small outline package; 24 leads; body width 5.3 mm SOT340-1

NAME DESCRIPTION VERSION

PACKAGE

1999 Jun 04 2

Philips Semiconductors Objective speciﬁcation

Cordless telephone line interface UBA1706

QUICK REFERENCE DATA

= 15 mA; VCC= 3.3 V; R

line

f = 1 kHz; T

=25°C; bit AGC at logic 1, all other conﬁguration bits at logic 0; measured in the test circuit of Fig.14;

amb

unless otherwise speciﬁed.

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V I

V R

line

REGC

supply voltage 3.0 − 5.5 V current consumption from pin V

line current operating range normal operation 11 − 140 mA

DC line voltage 2.7 3.0 3.3 V DC mask slope in current regulation

mode

v(trx)

voltage gain

transmit amplifier from TXI to LN V receive amplifier from RXI to RXO V

∆G

v(trx)

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

=15mA

line

=10Ω; AGC pin connected to GND; Z

SLPE

normal operation; bit PD = 0 − 2.2 3.2 mA

power-down mode; bit PD = 1 − 110 150 µA

with reduced performance 3 − 11 mA

> 35 mA (typical);

line

=1MΩ; R

LVI

bit CRC = 1

= 50 mV (RMS) 10.6 11.6 12.6 dB

TXI

= 2 mV (RMS) 36.9 37.9 38.9 dB

RXI

=90mA − 6.5 − dB

line

= 7.15 kΩ;

RGL

= 600 Ω; Z

= 619 Ω; EHI = HIGH;

SET

− 1.4 − kΩ

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Philips Semiconductors Objective speciﬁcation

Cordless telephone line interface UBA1706

BLOCK DIAGRAM

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RGL

RXI

TXI+ TXI−

AGC

RGL

15 14

RX PREAMP

EHI

TX PREAMP

RAGC2

REG

CRC

RXM

RAGC1

EHI

600 mV

UBA1706

AGC

LOW VOLTAGE

SAGC, AGC

300 mV

PART

CURRENT

LIMITATION

SWITCH DRIVER PROTECTION

200 nA

LINE INTERFACE

EHI

SLPE

GND

RXO

SET

SLPE

REG

EHI LCC

CST

LVI

REG

ON-HOOK

DARL

CST

LVI

16, 20, 22, 23

n.c.

SERIAL

INTERFACE

12 13 11 EN CLK DATA

SUPPLY

SWC1, SWC2

Bit names are given in italics.

Fig.1 Block diagram.

1999 Jun 04 4

GENERAL SWITCHES

MBL039

SWI1

SWI2

Philips Semiconductors Objective speciﬁcation

Cordless telephone line interface UBA1706

PINNING

SYMBOL PIN DESCRIPTION

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

compensation adjustment RXI 9 receiver ampliﬁer input EHI 10 electronic hook switch control input DATA 11 serial bus data input EN 12 programming serial bus enable input CLK 13 serial bus clock input TXI− 14 inverted transmit ampliﬁer input TXI+ 15 non-inverted transmit ampliﬁer input n.c. 16 not connected SWI2 17 NPN open-collector output 2 SWI1 18 NPN open-collector output 1 GND 19 ground reference n.c. 20 not connected V

21 supply voltage n.c. 22 not connected n.c. 23 not connected SLPE 24 connection for slope resistor

handbook, halfpage

REG

LVI

RGL

LCC

CST

UBA1706

RXO

AGC

RXI

EHI

DATA

FCA031

Fig.2 Pin configuration.

SLPE

n.c.

GND

SW1

SW2

n.c.

TXI+

TXI-

CLK

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Philips Semiconductors Objective speciﬁcation

Cordless telephone line interface UBA1706

FUNCTIONAL DESCRIPTION

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

Supply (pins V

and GND; bit PD)

The UBA1706 must be supplied with an external stabilized voltage source across pins V

and GND.

Without any signal 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 or SWI2) increases the current consumption by 600 µA.

To drastically reduce current consumption, the UBA1706 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 the power-down mode, the serial interface is the only function which remains active.

Line interface

8.5

handbook, halfpage

ref

(V)

7.5

6.5

5.5

4.5

3.5

2.5

(1)

(2)

MGK706

RVA (Ω)

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

DC LCC, RGL

The IC generates a stabilized reference voltage (V

AND GND; BIT CRC)

ref

) across 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). The reference voltage 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

) which is connected to GND. This

REG

capacitor, converted to an equivalent inductance (see Section “Set impedance”) realizes the set impedance conversion from its DC value (R (Z

in the audio frequency range). Figure 4 illustrates

SET

) to its AC value

SLPE

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 UBA1706. Therefore, using the RVA resistor to change the value of the reference voltage will also modify all parameters related to the line current such as:

• The AGC

• The DC mask management

• The low voltage area characteristics.

(1) Influence of RVA on V (2) V

without influence of RVA.

ref

Fig.3 Reference voltage adjustment with RVA.

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

V I

SLPEIlineIZSET

refRSLPEISLPE

×+=

I* I

–≅––=

lineIZSET

Where:

= line current

line

= current flowing through Z

ZSET

SET

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

The preferred value for R

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.

Nevertheless, for compliance with CTR21, 8.66 Ω is the optimum value for R

SLPE

In the same way, changing the value of Z

also affects

SET

the characteristics. The IC has been optimized for V

= 2.9 V and Z

ref

SET

= 619 Ω.

1999 Jun 04 6

Philips Semiconductors Objective speciﬁcation

Cordless telephone line interface UBA1706

handbook, full pagewidth

35 kΩ

4 kΩ

REG GNDSLPE

REG

4.7 µF

SLPE

UBA1706

SLPE

10 Ω

ZSET

Fig.4 Reference voltage supply configuration.

FCA032

line

SET

619 Ω

LN+

handbook, full pagewidth

35 kΩ

4 kΩ

REG GND LCC EHISLPE

REG

4.7 µF

SLPE

10 Ω

Fig.5 Line current settling simplified configuration.

UBA1706

ref

HOOK SWITCH MANAGEMENT

EHI

(TNSW)

line

ZSET

SET

619 Ω

LN+

LN−

line

exch

line

exch

FCA033

1999 Jun 04 7

Philips Semiconductors Objective speciﬁcation

Cordless telephone line interface UBA1706

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

) and the set (R

line

), the DC resistors of the telephone line

exch

), the reference voltage (V

SET

), the feeding bridge

exch

ref

) and the voltage introduced by the transistor (TNSW) used as line interrupter (see Fig.5).

With a line current below I internal reference voltage (V

(8 mA with Z

low

) is automatically adjusted

ref

SET

= 619 Ω), the

to a lower value. This means that several sets can operate in parallel with DC line voltages (excluding the polarity guard) down to 1.2 V. With a 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 detail how the UBA1706, 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 transistor TP resistor RPD, transistors TNSWand TN switched off. Transistor TN R

from the LN− line terminal to guarantee a high

LVI

. As a result, because of

DARL

ON-HOOK

disconnects resistor

are

on-hook impedance.

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

, which forms a current amplifier

DARL

structure in association with TNSW. The line current flows through transistor TNSW. Transistor TN

ON-HOOK

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

resistor to generate a

LVI

) is

voltage source. Thus, the voltage across pins GND and LN− becomes:

VCE (TNSW)=R The voltage V

× I

LVI

LVI+VCE

across line terminals LN+ and LN− can

line

(TN

ON-HOOK

) ≅ R

LVI

× I

LVI

be calculated as follows: V

line

≅ V

ref+RSLPE

× (I

line

− I

ZSET

)+VCE(TNSW)

Where:

= line current

line

= current flowing through Z

ZSET

SET

1999 Jun 04 8

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1999 Jun 04 9

35 kΩ

UBA1706

line

Philips Semiconductors Objective speciﬁcation

Cordless telephone line interface UBA1706

LN+

REG

4.7 µF

EHI

REG

EHI

CURRENT

REGULATION

MODE

MANAGEMENT

CRC

RGL

7.15 kΩ

LVI

C 470 pF

ON-HOOK

LVI

1 MΩ

4 kΩ

LVIV

200 nA

GNDLVIRGL CST

prot

CURRENT

LIMITATION

ON-HOOK

100 kΩ

PLU

150 kΩ

CST

22 pF

SLPE

LCC

20 kΩ

ref

SLPE

10 Ω

DARL

ZSET

SLPE

8.2 V

Z 619 Ω

SET

line

FCA034

line

LN−

Bit names are given in italics.

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

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