Ericsson PBL3853N, PBL3853SO, PBL3853SO-T Datasheet

May 1996

PBL 3853

Universal Speech Circuit

Description

The PBL 3853 is a biopolar integrated speech circuit with specific parameters making
it highly suitable to be used as a line interface and speech circuit in a telephone line
powered electronic payphone. Emphasis has been put on low current consumption in
the IC thus facilitating that a greater part of the available line current can be used to
power other electrical functions in the design. From a minimum line current of
16 mA, 12 mA at 4.5 V can be used to power auxiliary functions. The circuit can
optionally create an active impedance towards the telephone line, set by external
passive components, to reduce the current consumption for the transmitted signal.
The circuit is designed to be used with a low impedance dynamic microphone but can
be used with an electret type as well. The receiver drives a low ohm dynamic
transducer directly. External clamping diodes are required on the receiver output.
Both transmitter and receiver can be muted separately (receiver cut off). Line length
regulation of the gain is possible in both receiver and transmitter. It is also possible to
use the circuit without regulation. Payphone tones and confidence tone in the recei­ver at DTMF dialling can be injected directly into the receiver amplifier where their
levels are not affected by line length regulation and without the signal going out on
the line. All pin numbers refer to DIP package unless otherwise noted.

PBL 3853

5

4

+V

10

1

9

-

+

+

7

+

8

-

Key Features

• Low own current consumption

• Can operate both with active and

passive impedance towards the line

• Derives a high current from the line
for auxiliary functions, 12 mA at
16 mA line current

• Separate mute inputs for transmitter
and receiver (receiver cut off)

• Line length regulation possible (line
loss compensation

• Comes in 18 pin DIP and 20-pin SO
package

• High line current operation, max.
130mA

• Especially suitable for payphone
applications

• DTMF - confidence tone input

• Excellent RFI performance

PBL3853

-

12

MA

Rx

13

6

14

Figure 1. Block diagram. Pin numbers in all figures refer to DIP package.

11

2

3

17

Tx

15

18

18-pin plastic DIP

16

PBL3853

20-pin plastic SO

PBL 3853

R -0-4kΩ

L

0 ohm when artificial
line is used

R = 400Ω+400Ω

feed

+

E= 50V

C = 1µF when artificial line is used
470µF when not used

5H+5H

V

I

L

+ LINE

MIC

I

DC

V

DC

Recelver
cut-off

Transmitter
mute

PBL 3853

see fig 4

-

LINE

Recevler
tone
input

REC

V

4

ARTIFICIAL

+

LINE

C

600Ω

V

2

1

V

L

Z

Rec

Z =150Ω

Mic

V

3

Z= 500Ω

V

5

=350Ω

Figure 2. Test set up without rectifier
bridge.

0 ohm when artificial
line is used

R = 400Ω+400Ω

feed

+

E= 50V

R1

R2

R

A

R

B

R -0-4kΩ

L

C1

Mic

+

C3

U = 15-16V

5H+5H

1µF

600Ω

V

2

V

1

PBL3853

5

AC-DC char. adjust

Transmitter mute

10

4

+

V

12

M

13

6

14

C

R

R

D

DTMF
In

R

DTMF

I

z

L

+ LINE

MIC

Recelver
cut-off

Transmitter
mute

PBL 3853

see fig 4

-

LINE

Recevler
tone
input

REC

V

Z

4

Rec

I

DC

V

L

V

DC

Z =150

Mic

V

3

Z= 500Ω

V

5

Ω

350

Ω

Figure 3. Test set up with rectifier bridge.

I

+ Line

R12

1

9

-

+

+

-

7

8

+

-

18

R 13

T2

T1

L

R1 = 2.7 k C1 = 150 nF

R2 = 22 Ω C2 = 10 nF

R3 = 6.8 k C3 = 47 µF
R4 = 1.8 k C4 = 220 nF
R5 = 75Ω C5 = 150 nF
R6 = 910 Ω C6 = 47 nF
R7 = 6.2k C7 = 100 nF
R8 = 560Ω C8 = 68 nF
R9 = 11 k C9 = 4.7µF

C9

16

Cut-off

R7

C6

15

R

x

Receiver

C7

R11

R10

+

Rec

D3

D2

C8

D1

C2

T

X

11

3

C4

C5

R3

R4

R5

2

Tone in

R6

17

R8

R9

R10 = 4.7k C10 = 22 µF
R11 = 120k

V

DC

R12 = 56Ω D1 = Z 4.5 V
R13 = 68Ω D2 = 1N4148

+

-Line

= 30 k* D3 = 1N4148

R

C

C10

R

= 11k*

D

* values for the test set up only

T1 = BC178B
T2 = BC178B

Figure 4. Reference figure with line length regulation. DIP-package.

2

PBL 3853

Absolute Maximum Ratings

Parameter Symbol Conditions Min. Max. Unit

Line voltage V
Continous operating line current, T
Continous operating line current, T

=70°CI

amb

=70°CI

amb

Input voltage, all inputs V
Operation temperature T
Storage temperature T

L

L

L

pinx

amb

sto

Dual In Line package 130 mA
Small Outline package 100 mA

-0.5 Vpin4+0.5 V

-20 +70 °C

-55 +125 °C

Electrical Characteristics

T

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

amb

Parameter Symbol fig. Conditions Min. Typ. Max. Unit

Terminal voltage 2 IL = 20 mA 6 V
Transmitter gain 2 20 •

Transmitter gain temp
dependence 2 I
Transmitter attenuation in
mute mode 2 60 dB
Transmitter frequencey response 2 200 Hz - 3.4 kHz -1 +1 dB
Receiver gain 2 20 •

Receiver gain temp dependence 2 IL = 20 mA, 0 - 50°C-1 +1dB
Receiver tone gain 2 20 •

Receiver frequency response 2 200 Hz - 3.4 kHz -1 +1 dB
Microphone input impedance 2 1 kHz 1.3 1.7 2.1 kΩ
(Differential)
Transmitter input impedance
Pin 3 4 1 kHz 13 17 21 kΩ
Transmitter dynamic output
voltage 2 200 Hz - 3.4 kHz < 10% distortion

Transmitter Max. output voltage 2 200 Hz - 3.4 kHz, V

Receiver input impedance
Pin 15 4 1 kHz 28 35 42 kΩ
Receiver tone input impedance
Pin 17 2 1 kHz, Not mute. Note 1 7.0 8.8 11 kΩ
Receiver output impedance 2 1 kHz 6 Ω

Ref

10

log (V2/ V3),1 kHz

I

= 57 mA 41.6 43.0 44.4 dB

L

= 0 Ω 41.0 43.0 45.0 dB

R

L

= 900 Ω - 2.2 kΩ 46.0 48.0 50.0 dB

R

L

I

= 20 mA 47.0 48.0 49.0 dB

L

= 20 mA, 0-50°C-1 +1dB

L

10

log(V4/ V1),1 kHz
IL = 57 mA -17.9 -16.5 -15.1 dB
RL = 0 Ω -18.5 -16.5 -14.5 dB
R

= 900 Ω - 2.2 kΩ -13.5 -11.5 -9.5 dB

L

IL = 20 mA -12.5 -11.5 -10.5 dB

10

log (V4/ V5), 1 kHz
IL = 25 mA 4.5 6 7.5 dB

I

= 20 mA - 100 mA 1.8 Vp

L

IL = 16mA, V

= 4.5V , IDC = 12mA 1.4 Vp

DC

IL = 16mA, VDC = 4.0V, IDC = 10mA 1.8 Vp

= 0 - 1Vrms

3

IL = 0 mA - 100 mA 3 Vp

22 V

3

PBL 3853

Parameter Symbol fig. Conditions Min. Typ. Max. Unit

Ref

Receiver dynamic output
voltage 2 200 Hz - 3.4 kHz< 2% distortion

I

= 20 mA - 100 mA 0.6 Vp

L

Zrec = 150 Ω 0.25 Vp

Receiver Max. output voltage 3 Measured with rectifier

200 Hz - 3.4 kHz
I

= 0 mA - 100 mA

L

V

= 0 -50 Vrms 0.8 Vp

1

Transmitter output noise 2 Psoph - weighted rel. 1 V

RL = 900 Ω -74 dB

Receiver output noise 2 Psoph - weighted rel. 1 V, with cable: -80 dB

0 - 5 km, Ø = 0.5 mm
0 - 3 km, Ø = 0.4 mm

Mute input voltage at mute
(transmit) V

M

22V
Input voltage at cut off
(receive) V

M

2 Note1 3 V
DC-supply current 2 IL = 16 mA, VDC = 4.5 V 12 mA

Note: 1. This input has three functions (see page 7). No input should be set on higher level than +V.

Psoph

Psoph

4

+L

PBL 3853

1

18

VDC

TO

2

TI

3

+C

4

DCAC

5

GR

6

T2

7

T1

8

FE TM

9 10

17

16

15

14

13

12

11

RI 2
RO
RI 1

-L
MI 2
MI 1
MO

+L

TO

+C

DCAC

GR

T2

NC

1

2

3

TI

4

5

6

7

T1

8

912

FE

10

20

VDC

RI2

19

RO

18

RI1

17

-L

16

MI 2

15

14

MI 1
MO

13

TM

11

NC

18 pin-DIP 20 pin-SO

Figure 5. Pin configuration.

Pin Description

DIP SO Symbol

1 1 +L Output of the transmitter (+Line side)
2 2 TO Output of the transmitter (side tone signal)
3 3 TI Input of the transmitter amplifier
4 4 +C The circuit supply (sinks ~ 0,3 mA)
5 5 DCAC Adjustment for DC-char. and AC imp. to line
6 6 GR Gain regulation starting point setting
7 7 T2 Output for transistor 2, active when voltage on the line is too low for VDC
8 8 T1 Output for transistor 1, active when charging current into VDC’s reservoir capacitor
9 9 FE Feedback

10 NC No connection

11 NC No connection
10 12 TM Transmitter mute input
11 13 MO Microphone amplifier output
12 14 MI
13 15 MI
14 16 -L Negative terminal of the circuit
15 17 RI1 Receiver amplifier input (gain control)
16 18 RO Receiver amplifier output
17 19 RI 2 Receiver amplifier input for cut-off, see page 7.
18 20 VDC VDC supply terminal

1 Microphone amplifier inverting input
2 Microphone amplifier non inverting input

5