Ericsson PBL38570-1N, PBL38570-1SO, PBL38570-1SOT Datasheet

PBL 385 70

Universal Speech Circuit

20-pin plastic SO

18-pin plastic DIP

September 1997

Figure 1. Functional diagram. DIP package.

1

Description.

PBL 38570 is a monolithic integrated speech transmission circuit for use in electronic telephones. It is designed to accomodate either a low impedance dynamic or an electret microphone. A separate input for DTMF dialling tones that is controlled by a mute signal, and a signal summing point at the transmitter input, are available.

An internally preset line length compensation can be adjusted with external resistors to fit into different current feed systems as for ex. 48 V, 2 x 200 ohms, 48 V, 2 x 400 ohms and 48 V, 2 x 800 ohms. The line length compensation can be shut off in either high or low gain mode. Application dependent parameters such as line balance, side tone level, transmitter and receiver gains and frequency responces are set independently by external components which means an easy adaption to various market needs.

The setting of the parameters if carried out in certain order will counteract the interaction between the settings.

A number of different DC - supplies are provided to feed microphones and diallers.

Key features.

• Minimum number of external components, 7 capacitors and 11 resistors.

• Easy adaption to various market needs.

• Mute control input for operation with DTMF - generator.

• A separate input for DTMF tones controlled by mute.

• Transmitter and receiver gain regulation for automatic loop loss compensation.

• Extended current and voltage range 5 - 130 mA, down to 2 V.

• Differential microphone input for good balance to ground.

• Balanced receiver output stage.

• Stabilized DC - supplies for low current CMOS diallers and electret microphones.

• 18 - pin DIP and 20 - pin SO packages.

• Short start up time.

• Excellent RFI performance.

PBL 38570

1. Line impedance and radio interference suppression.

2. Transmit gain and frequency response network.

3. Receive gain and frequency response network.

4. Side tone balance network.

5. DC-supply components.

17

14

2311

12

13

18

16

AM

AT

5

AR

15

4

+

10

AD

1

PBL 385 70

79

Sense input

DTMF

input

+

6

Mic.

8

DC-supply

+

Mute

(active low)

DC-output for external devices

Telephone line

5

2

4

3

1

Gain regulation

PBL 385 70

2

Figure 2. Test set up without rectifier bridge.

Figure 3. Test set up with rectifier bridge.

Figure 4. Circuit with external components for test set up. * Not used in test set up. 18 pin DIP package.

Maximum Ratings

Parameter Symbol Min Max Unit

Line voltage, tp = 2 s V

L

018V

Line current, continuous DIP I

L

0 130 mA

Line current, continuous SO package I

L

0 100 mA

Operating temperature range T

Amb

-40 +70 °C

Storage temperature range T

Stg

-55 +125 °C

No input should be set on higher level than pin 4 (+C).

+

= 350Ω

+ LINE

- LINE

ARTIFICIAL

LINE

I

L

V

2

V

1

V

L

R = 0-4kΩ

L

0 ohm when artificial line is used

MUTE

PBL 385 70 with external components

See fig. 4

Z

Mic

= 350Ω

Z

Rec

MIC

REC

R

feed

= 400Ω+400Ω

600Ω

C

E = 48.5V

V

3

V

4

I

DC1

C = 1µF when artificial line is used 470µF when no artificial line

V

M

DC2

I

V

DC1

V

DC2

5H+5H

+

I

M

+

+ LINE

- LINE

I

L

V

2

V

1

V

L

R = 0 - 4kΩ

L

MUTE

PBL 385 70 with external components

See fig. 4

Z

Mic

Z

Rec

MIC

REC

R

feed

= 400Ω+400Ω

600Ω

+

E = 50.0V

V

3

V

4

1µF

V

M

Uz= 15-16V

5H+5H

I

DC1

DC2

I

V

DC1

V

DC2

= 350Ω

I

M

17

14

2311

12

13

18

16

AM

AT

5

AR

15

4

+

10

AD

1

PBL 385 70

79

Sense input

DTMF

input

+

6

Gain regulation

Mic. 350Ω

8

DC-supply

+

Mute

(active low)

DC-output for external devices

2.7k

47µF

*

18k

22k

100n

75Ω

910Ω

560Ω

11k

100n

6.2k

11k

10Ω

62k

47µF

15n

Rec. 350Ω

310Ω

220n

-Line

+Line

910Ω

47n

C1

C2

C3

C5

C6

C7

R1

R2

R4

R5

R6

R7

R8

R9

R10

R11

R12

R13

R3

R14

R16

C9

PBL 385 70

3

Electrical Characteristics

At T

Amb

= + 25° C. No cable and line rectifier unless otherwise specified.

Parameter fig. Conditions Min Typ Max Unit

Line voltage, V

L

2I

L

= 15 mA 3.3 3.7 4.1 V

2I

L

= 100 mA 11 13 15 V

Transmitting gain, note 1 20 •

10

log (V2 / V3); 1 kHz

2R

L

= 0 414345dB

2R

L

= 400 Ω 43.5 45.5 47.5 dB

2R

L

= 900 Ω - 2.2 kΩ 46 48 50 dB

Transmitting range of 2 1 kHz, R

L

= 0 to 900 Ω 357dB regulation Transmitting frequency 2 200 Hz to 3.4 kHz -1 1 dB response Transmitter input impedance 2 1 kHz 13.5 17 20.5 kΩ pin 3 Transmitter dynamic output 2 200 Hz - 3.4 kHz 1.5 V

p

≤ 2% distortion, IL = 20 - 100 mA

Transmitter max output 2 200 Hz - 3.4 kHz 3 V

p

IL = 0 - 100 mA, V3 = 0 - 1 V

Transmitter output noise 2 Psoph-weighting, Rel 1 V

rms

, RL = 0 -75 dB

Psoph

Microphone input impedance 2 1 kHz 1.7(//2.7) kΩ pin 12 (14),13 (15) note 3 Receiving gain, note 1 20 •

10

log (V4 / V1); 1 kHz

2R

L

= 0 Ω -18.5 -16.5 -14.5 dB

2R

L

= 400 Ω -16 -14 -12 dB

2R

L

= 900 Ω - 2.2 kΩ -13.5 -11.5 -9.5 dB

Receiving range of regulation 2 1 kHz, R

L

= 0 to 900 Ω 357dB Receiving frequency response 2 200 Hz to 3.4 kHz -1 1 dB Receiver input impedance 2 1kHz 30.4 38 45.6 kΩ

Receiver output impedance 2 1 kHz, 3(+310), note 3 Ω Receiver dynamic output 2 200 Hz - 3.4 kHz 0.5 V

p

note 2 ≤ 2% distortion, IL = 20 - 100 mA Receiver max output 3 Measured with line rectifier 0.9 V

p

200 Hz - 3.4 kHz, IL = 0 - 100 mA, V

1

= 0 - 50 V

Receiver output noise 2 A-weighting, Rel 1V

rms

, with cable -85 dB

A

0 - 5 km, Ø = 0.5 mm, 0 - 3 km,

Ø = 0.4 mm Mute input voltage 2 0.3 V at mute (active low) DC-supply voltage 2 I

L

= 20 - 100 mA

I

DC

= 0 mA 2.1 2.35 2.6 V

I

DC

= 2 mA 1.95 2.2 2.6 V DC-supply current, pin 8. 2 2 mA DC-output pin 8 input 4 VDC = 2.35 V 0.1 µA leakage current (no supply) DTMF transmitting gain 2 VM = 0.3 V, 1 kHz 24.5 26.5 28.5 dB DTMF input impedance 2 1 kHz 20 25 30 kΩ

Notes

1. Adjustable to both higher and lower values with external components.

2. The dynamic output can be doubled, see applications information.

3. External resistor in the test set up.

Ref.

PBL 385 70

4

Figure 5. Pin configuration.

18-pin DIP

20-pin SO

}

+L

TO

TI

+C

Mute

GR

DCS

DCO

DR RI

-L MI 2 MI 1 MO

1 2 3 4 5 6 7 8

16 15 14 13 12 11

DCC DI

9 10

RE 2 RE 1

18 17

1

2

3

4

5

6

7

8

19

18

17

16

15

14

13

+L

TO

TI

+C

Mute

GR

DCS

DCO

RE 2 RE 1 DR RI

-L MI 2 MI 1 MO

9

12

10

11

DCC

NC

DI NC

4

5

17

16

20

Pin Descriptions

Refer to figure 5.

DIP SO Name Function

1 1 +L Output of the DC-regulator and transmit amplifier, connected to the line through a polarity

guard diode bridge.

2 2 TO Output of the transmit amplifier, connected through a resistor of 47 to 100 ohm to -L,

sets the DC-characteristics of the circuit. The output has a low AC output impedance and the

signal is used to drive a side tone balancing network. 3 3 TI Input of transmit amplifier. Input impedance 17 kohm ± 20 %. 4 4 +C Positive power supply terminal for most of the circuitry inside the PBL 385 70 (about 1 mA current

consumption). The +C pin must be connected to a decoupling capacitor of 47 µF to 150 µF. 5 5 Mute When low, speech circuit is muted and the DTMF input is enabled. Maximum voltage (at mute) is

0.3 V, current sink requirement of external driver is min. 50 µA. 6 6 GR Control input for the gain regulation circuitry. 7 7 DCS Sense input to the DC-supply. 8 8 DC1 Output from the DC-supply. 9 9 DC2 Control of the DC-supply. 10 12 DI Input for the DTMF-signal. Input impedance is 25 kohm ± 20 %. 11 13 MO Output of the microphone amplifier or DTMF-amplifier. 12 14 MI 1

Inputs to the microphone amplifier. Input impedance 1.7 kohm ± 20 %.

13 15 MI 2 14 16 -L The negative power terminal, connected to the line through a polarity guard diode bridge. 15 17 RI Input of receiver amplifier. Input impedance is 38 kohm ± 20 %. 16 18 DR Control input for the receiver amplifier driving capacity. 17 19 RE 1

Receiver amplifier outputs. Output impedance is approximately 3 ohm.

18 20 RE 2

10 NC 11 NC