Philips UBA1702T-C1, UBA1702AT-C1, UBA1702A-C1 Datasheet

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INTEGRATED CIRCUITS

DATA SHEET

UBA1702; UBA1702A

Line interrupter driver and ringer

Product speciﬁcation

1997 Sep 29

Supersedes data of 1996 Jan 09

File under Integrated Circuits, IC03

Philips Semiconductors	Product speciﬁcation

Line interrupter driver and ringer	UBA1702; UBA1702A

FEATURES

Speech part

∙Driver for the line interrupter that can be either a PMOST when UBA1702 is used or a PNP when UBA1702A is used

∙Adjustable over-current protection

∙Adjustable over-voltage protection for transmission circuit

∙Adjustable mute (dialling mode voltage; DMO or NSA)

∙Adjustable current loop detection (hook switch status)

∙Microcontroller supply

∙Provision for electronic hook switch.

Ringer part

∙Over-voltage protection

∙Ringer frequency output for frequency discrimination

∙Adjustable ringer threshold for piezo-driver enable

∙Three bits ringer volume control

∙Bridge-tied-load (BTL) output stage for piezo transducer

∙Fast start-up microcontroller supply.

ORDERING INFORMATION

Miscellaneous

∙Separated ground pins for transmission circuit interface and control signals (e.g. for TEA1064A)

∙Possibility to supply the microcontroller with an external voltage source.

APPLICATIONS

∙Telephone sets with software controlled ringer function

∙Telephone sets with electronic hook switch.

GENERAL DESCRIPTION

The UBA1702; UBA1702A performs the high voltage interface and ringer functions of the corded analog telephone set in close cooperation with a microcontroller and transmission circuit.

The UBA1702; UBA1702A incorporates several protections, a driver for the line interrupter and a ringer. Because of the practical division of functions between the microcontroller, the transmission circuit and the UBA1702; UBA1702A, it is possible to have a higher integration level thereby reducing significantly the number of discrete components in a telephone set.

TYPE NUMBER		PACKAGE

	NAME	DESCRIPTION	VERSION
	NAME	DESCRIPTION	VERSION

UBA1702	DIP28	plastic dual in-line package; 28 leads (600 mil)	SOT117-1

UBA1702A	DIP28	plastic dual in-line package; 28 leads (600 mil)	SOT117-1

UBA1702T	SO28	plastic small outline package; 28 leads; body width 7.5 mm	SOT136-1

UBA1702AT	SO28	plastic small outline package; 28 leads; body width 7.5 mm	SOT136-1

1997 Sep 29

Philips Semiconductors	Product speciﬁcation

Line interrupter driver and ringer	UBA1702; UBA1702A

QUICK REFERENCE DATA

Speech part: lline = 20 mA; DPI = LOW; Tamb = 25 °C; VEE = 0 V; unless otherwise speciﬁed.

Ringer part: Vline(rms) = 45 V; f = 25 Hz; using an RC combination of 2.2 kΩ and 820 nF and a diode bridge between the line and the RPI input.

SYMBOL	PARAMETER	CONDITIONS	MIN.	TYP.	MAX.	UNIT

Speech part

SWITCH DRIVER AND REFERENCES (PINS SDI, SDO, EHI AND DPI); UBA1702A ONLY

RSDO	resistance between pins SDO and VEE		−	2.2	−	kΩ
SWITCH DRIVER AND REFERENCES (PINS SDI, SDO, EHI AND DPI); UBA1702 AND UBA1702A

RSDI-SDO	resistance between pins SDI and SDO	VSDI − VSDO < 12 V	−	1.1	−	MΩ
RSDI	resistance between pins SDI and VEE	VSDI = 240 V; DPI = HIGH	5	−	−	MΩ
MUTE SWITCH AND ADJUSTABLE PROTECTION ZENER VOLTAGE (PINS MSI, MSA AND ZPA)

VSPO(M)	adjustable mute voltage referenced to	MSI = HIGH;	−	2.7	3	V
	VEE	MSA open-circuit
VSPO(Z)	adjustable zener voltage referenced to	MSI = LOW;	11	12	13	V
	VEE	ZPA open-circuit
CURRENT MANAGEMENT (PINS SPI, SPO, CDA, CLA AND CDO)

lSPI(lim)	current limitation (pin SPI)	CLA shorted to VEE	−	120	−	mA
ISPI(det)	current detection (pin SPI)	CDA open-circuit	2	3	4	mA
MICROCONTROLLER SUPPLY (VDD AND VBB)

VDD	supply output voltage referenced to	VBB > 3.7 V; IDD = −1 mA	3.0	3.3	3.6	V
	VSS
Ringer part

PROTECTION (PIN RPI)

IRPI(max)	maximum input current		70	−	−	mA
RINGER THRESHOLD AND FREQUENCY DETECTION (PINS VRR, RTA AND RFO)

VRR(th)	ringer supply threshold voltage	RTA open-circuit	−	11	−	V
	referenced to VSS
VOLUME CONTROL (PINS RV0, RV1 AND RV2)

Gs	step resolution	(RV2, RV1, RV0) from	−	6	−	dB
		(0, 0, 0) to (1, 1, 0); note 1

Gls	last step resolution	(RV2, RV1, RV0) from	−	9.5	12	dB
		(1, 1, 0) to (1, 1, 1); note 2

RINGER MELODY INPUT AND PIEZO DRIVER (PINS RMI, ROA AND ROB)

Vo(max p−p)	maximum output voltage between pins	RV2 = 1; RV1 = 1; RV0 = 1	−	28.7	32	V
	ROA and ROB (peak-to-peak value)

Notes

1.Independent of VRR if greater than 10 V.

2.Without piezo transducer, dependent on VRR.

1997 Sep 29

Philips UBA1702T-C1, UBA1702AT-C1, UBA1702A-C1 Datasheet

Philips Semiconductors	Product speciﬁcation

Line interrupter driver and ringer	UBA1702; UBA1702A

BLOCK DIAGRAM

SDO

CDO

SPI

SDI

CLA

CDA

SPO

SPEECH

ZENER PROTECTION

VSS

VDD

ZPA

14 V

SENSE

S ref

DPI

MSA

Sref

EHI

Sref

VDD

R ref

VSS

MSI

SWITCH

VSS

DRIVER

LINE CURRENT MANAGEMENT

MUTE SWITCH

SUPPLY

Sref

VSS

UBA1702; UBA1702A

SPO

VBB

UBA1702T; UBA1702AT

VEE

Vref

REFERENCES

VDD

VSS

VRR

Rref

ROA

VRR

RINGER FREQUENCY

RINGER

VSS

VDD

DETECTION

VSS

VDD

ROB

VDD

RFO

1/2 VDD

VDD

VSS

RINGER MELODY INPUT AND PIEZO DRIVER

VRR

VDD

RPI

RV0

VSS

R ref

DIGITAL

-TO-

ANALOG

RV1

CONVERTER

VSS

R ref

VSS

VDD

RV2

RINGER

VOLUME

VSS

PROTECTION

THRESHOLD

CONTROL

MBE184

RTA

RMI

VRR

Fig.1 Block diagram.

1997 Sep 29

Philips Semiconductors	Product speciﬁcation

Line interrupter driver and ringer	UBA1702; UBA1702A

PINNING

SYMBOL	PIN	DESCRIPTION

SDI	1	switch driver input

SDO	2	switch driver output

n.c.	3	not connected

DPI	4	dialling pulse input

SPI	5	speech part input

SPO	6	speech part output	handbook, halfpage

VEE	7	ground for transmission circuit
VEE	7	ground for transmission circuit
MSI	8	mute switch input

ZPA	9	Zener protection adjustment input

MSA	10	mute switch adjustment input

RTA	11	ringer threshold adjustment input

RFO	12	ringer frequency output

RV0	13	ringer volume input; bit 0

RV1	14	ringer volume input; bit 1

RV2	15	ringer volume input; bit 2

RMI	16	ringer melody input

VSS	17	ground for microcontroller and
		ringer

VDD	18	microcontroller supply voltage
VBB	19	supply voltage from transmission
		circuit

ROB	20	ringer output B

VRR	21	ringer supply voltage
ROA	22	ringer output A

RPI	23	ringer part input

CDO	24	current detection output

CLA	25	current limitation adjustment input

CDA	26	current detection adjustment input

n.c.	27	not connected

EHI	28	electronic hook switch input

SDI	1		28	EHI
SDO	2		27	n.c.
n.c.	3		26	CDA
DPI	4		25	CLA
SPI	5		24	CDO
SPO	6		23	RPI
VEE	7	UBA1702	22	ROA
VEE	7	UBA1702T	22	ROA
		UBA1702T
MSI	8	UBA1702A	21	VRR
MSI	8	UBA1702AT	21	VRR
		UBA1702AT
	9
ZPA	9		20	ROB
	10			VBB
MSA	10		19	VBB
	11			VDD
RTA	11		18	VDD
	12			VSS
RFO	12		17	VSS
RV0	13
RV0	13		16	RMI

RV1	14		15	RV2

		MBE183

Fig.2 Pin configuration.

1997 Sep 29

Philips Semiconductors	Product speciﬁcation

Line interrupter driver and ringer	UBA1702; UBA1702A

FUNCTIONAL DESCRIPTION

The values given in this functional description are typical values except when otherwise specified.

Speech part

The speech part consists of three blocks, the switch driver, the line current management and the mute switch (DMO or NSA) combined with an adjustable over-voltage (zener) protection circuit. The reference block, which generates reference voltages and currents, is also used in the speech part (see Fig.1) by the mute switch block.

SWITCH DRIVER (PINS SDI, SDO, EHI AND DPI)

UBA1702

The UBA1702 switch driver block is intended to generate the appropriate signal to drive an external PMOST interrupter. The source and gate of this PMOST are respectively connected to SDI and SDO. The electronic hook switch input (EHI) and the dialling pulse input (DPI) signals control the state of this PMOST.

The EHI pin is provided with high voltage capability. When the voltage applied at pin EHI is HIGH, the switch driver block will start and generate the proper signals to switch on the external PMOST interrupter.

When the telephone set is equipped with a mechanical hook switch, pin EHI can be connected directly to the switch driver input (pin SDI). For electronic hook switch applications, the EHI pin can be driven by the microcontroller output.

In some special applications, the EHI pin can be current driven. In such a case, the current available at SDO to turn on the PMOST interrupter is approximately 10 times the EHI input current (providing IEHI < 2 μA).

The EHI pin presents an impedance of 250 kΩ at low input voltage. When the applied voltage at EHI goes above approximately 30 V, the EHI input current remains constant (see Fig.3) so that the EHI impedance increases.

The DPI is designed to switch on or off the external PMOST interrupter (providing EHI is HIGH). When the voltage applied at pin DPI is HIGH, the switch driver block turns off the external PMOST interrupter. When the

voltage applied at pin DPI is LOW, the switch driver block turns on the external PMOST interrupter.

The external PMOST interrupter is controlled by the voltage between the switch driver input and output (pins SDI and SDO).

When the voltage applied at pin EHI is HIGH and the voltage applied at pin DPI is LOW, the voltage at SDO is pulled down to a value less than 0.2 V in order to create a high source-gate voltage (VSG) for the external PMOST. However, in order to avoid break-down of the external PMOST, the voltage difference between SDI and SDO is internally limited to 14 V.

When the voltage applied at pin EHI and the one applied at pin DPI are both HIGH, pin SDO can be considered as being connected to pin SDI via a 1.1 MΩ pull-up resistor while the impedance between SDI and VEE becomes very high (a few MΩ).

When the voltage applied at pin EHI is LOW, whatever the one applied at DPI is, pin SDO can be considered as being connected to pin SDI via a 1.1 MΩ pull-up resistor while the impedance between SDI and VEE becomes almost infinite.

MGD178

IEHI (μA)

100

200

300

400

VEHI (V)

Fig.3 EHI input characteristics.

1997 Sep 29

Philips Semiconductors	Product speciﬁcation

Line interrupter driver and ringer	UBA1702; UBA1702A

UBA1702A

The UBA1702A switch driver block is intended to generate the appropriate signal to drive an external PNP interrupter. The emitter and base of this PNP are respectively connected to SDI and SDO. The EHI and DPI signals control the state of this PNP.

The EHI pin is provided with high voltage capability. When the voltage applied at pin EHI is HIGH, the switch driver block will start and generate the appropriate signals to switch on the external PNP interrupter.

When the telephone set is equipped with a mechanical hook switch, pin EHI can be connected directly to pin SDI. For electronic hook switch applications, the EHI pin can be driven by the microcontroller output.

The DPI is designed to switch on or off the external PNP interrupter (providing EHI is HIGH). When the voltage applied at pin DPI is HIGH, the switch driver block turns off the external PNP interrupter. When the voltage applied at pin DPI is LOW, the switch driver block turns on the external PNP interrupter.

The external PNP interrupter is controlled by the current flowing into pin SDO.

When the voltage applied at pin EHI is HIGH and the voltage applied at pin DPI is LOW, pin SDO can be considered as being connected to pin VEE via a 2.2 kΩ resistor in order to create a base current for the external PNP.

LINE CURRENT MANAGEMENT

(PINS SPI, SPO, CDA, CLA AND CDO)

The line current is measured by an internal 2 Ω resistor and a sense circuit connected between the speech part input and output (pins SPI and SPO). The circuit delivers information about the hook switch status at the current detection output (pin CDO) and controls the line current limitation.

When the SPI current exceeds a certain level (3 mA), the sense circuit injects some image of the SPI current into an internal resistor (see Fig.1). The created voltage becomes higher than an internal reference (approximately 0.3 V) and CDO goes HIGH. This current detection level can be increased by connecting a resistor between pins CDA (current detection adjustment) and VEE. It is also possible to connect a capacitor between pins CDA and VEE to filter unwanted AC components of the line current signal. Line current interruption during pulse dialling influences the CDO output.

When the SPI current exceeds another current level (45 mA), the sense circuit injects some image of the SPI current into an internal resistor (see Fig.1). The created voltage becomes higher than an internal reference

(approximately 0.4 V) and an internal signal is generated in order to limit the current in the external interrupter thus resulting in a line current limitation. This line current limitation level can be increased up to a maximum value of 120 mA by connecting a resistor between pins CLA (current limitation adjustment) and VEE.

When a PMOST (UBA1702) is used as an interrupter, the SPI current equals the drain or source current of the PMOST and thus also equals the line current.

When a PNP (UBA1702A) is used as an interrupter, the SPI current equals the collector current of the PNP and thus differs from the line current (the PNP base current does not flow into the SPI pin).

1997 Sep 29

Philips Semiconductors	Product speciﬁcation

Line interrupter driver and ringer	UBA1702; UBA1702A

MUTE SWITCH AND ZENER PROTECTION

(PINS MSI, MSA AND ZPA)

The mute switch is, in fact, a switchable and electronic zener diode connected between the speech part output (pin SPO) and VEE.

When the voltage applied at the mute switch input

(pin MSI) is LOW, the switch is in over-voltage protection mode and the maximum SPO voltage is limited to 12 V. This level can be increased or decreased by connecting a resistor between pins ZPA (zener protection adjustment) and VEE or ZPA and SPO respectively.

When the voltage applied at pin MSI is HIGH, the switch is in mute mode (DMO or NSA) resulting in a SPO voltage below 3 V. This level can be decreased by connecting a resistor between pins MSA (mute switch adjustment) and SPO. It should be noted that the mute switch stage is supplied from VDD thus a minimum voltage of approximately 2.1 V is required on VDD.

REFERENCE

The bias currents and voltages for the various speech blocks are generated by the reference block which is, in most cases, supplied from pin SPO. This block guarantees a high AC impedance at the SPO pin operating down to a low SPO voltage. Therefore, most speech part blocks operate independently from VDD.

Ringer part

The ringer part consists of five blocks, the ringer protection, the ringer threshold, the ringer frequency detection, the volume control and the piezo driver.

The reference block which generates reference voltages and currents is also used in the ringer part (see Fig.1).

RINGER PROTECTION (PINS RPI AND VRR)

The ringer protection block converts the ringing current into a limited voltage between the ringer part input (pin RPI) and VEE. This voltage is used (via an internal

diode) to generate the ringer supply voltage VRR which is mainly used for all ringer parts. The voltage at pin VRR must be filtered with a 22 μF capacitor connected between pins VRR and VSS.

In electronic hook switch applications and also in speech mode (see Fig.8), pin RPI is always connected to the telephone line (through a series RC network and a diode bridge). In order not to disturb normal speech operation, a high AC impedance is present at pin RPI (providing the speech level is less than 1.5 V (RMS) i.e. 5.7 dBm).

In the DMO or NSA mode (i.e. MSI is HIGH), the voltage across RPI and VEE is limited to 2.1 V. With this feature and in electronic hook switch applications, several additional ringers can be placed in parallel without tinkling during pulse dialling phase.

RINGER THRESHOLD (PIN RTA)

The piezo driver is internally enabled when the voltage at pin VRR exceeds a threshold level of 11 V. This threshold level can be increased or decreased by connecting a resistor between pins RTA (ringer threshold adjustment) and VSS or RTA and VRR respectively.

Because of the built-in 6.5 V hysteresis, a voltage change at pin VRR (coming from current consumption increase when the piezo output is driven with a melody) will have no influence on this internal enabling signal.

RINGER FREQUENCY DETECTION (PIN RFO)

The ringer frequency detection block generates a square wave signal at the ringer frequency output (pin RFO) with twice the ringer signal frequency. This RFO signal can be used by the microcontroller for frequency discrimination.

When the voltage at pin RPI drops below the voltage at pin VDD, RFO goes LOW. Pin RFO goes HIGH when the voltage at pin RPI exceeds the voltage at pin VRR.

This VRR − VDD hysteresis allows the frequency detection circuit to ignore parasitic signals superimposed on the ringing signal.

The voltage at pin EHI must be LOW to get a square wave at pin RFO. When the voltage at pin EHI is LOW, the voltage at pin RFO is always HIGH whatever the one at pin RPI is.

VOLUME CONTROL (PINS RV0, RV1 AND RV2)

The volume control input has three bits RV2, RV1 and RV0 to realize eight volume levels. The volume is controlled by regulating the supply voltage of the piezo output stage.

The first six steps have a fixed value of 6 dB, the value of the last step (maximum volume) is dependent on the available voltage at pin VRR.

Default setting during start-up is (RV2 = 0, RV1 = 0, RV0 = 0) which corresponds to minimum volume. In order not to damage the piezo transducer, the differential output ROA − ROB is internally limited to a value less than

32 V (p-p).

1997 Sep 29

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