PBL38541 Datasheet, PDF (1/14 Pages) Ericsson – Universal Speech Circuit

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PBL 385 41
Universal Speech Circuit
Description.
Key features.
PBL 38541 is a monolithic integrated speech transmission circuit for use in • Minimum number of external
electronic telephones or in any other line interface application. High settable supply
components, with two filtered DC-
current for auxiliary functions, up to 6.0 mA (at high line currents). The circuit is designed
supplies, 7 capacitors and 11
to accomodate either a low impedance dynamic or an electret microphone. Microphone
resistors.
can be muted separately. Payphone signaling and DTMF dialling tones have a separate • Easy adaption to various market
input that is controlled by a mute signal. A signal summing point is available at the
needs.
transmitter input. An internally preset line length compensation can be adjusted with • Mute control input for operation with
external resistors to fit into different current feed systems as for ex. 48 V, 2 x 200 ohms,
DTMF - generator.
48 V, 2 x 400 ohms and 48 V, 2 x 800 ohms. The line length compensation can be shut • A separate signaling input for
off in either high or low gain mode. Application dependent parameters such as line
payphone and DTMF tones controlled
balance, side tone level, transmitter and receiver gains and frequency responces are set
by mute.
independently by external components which means an easy adaption to various market • Transmitter and receiver gain
needs. The setting of the parameters if carried out in certain order will counteract the
regulation for automatic loop loss
interaction between the settings. The circuit provides four different DC - supplies to feed
compensation.
microphones,diallers and other more current consuming functions like handsfree systems. • Extended current and voltage range
4 - 130 mA, down to 2 .2V.
Pin numbers in this datasheet refer to 18-pin DIP package unless otherwhise noted. • Differential microphone input for good
balance to ground.
• Balanced receiver output stage.
• One stabilized DC - supply for low
current CMOS diallers and or electret
1
DTMF
10
input
AD
PBL 385 41
17
AT
12
Mic.
13
AM
AR
18
Mute
(active low)
DC1- output for
external devices
DC2 - output for
external devices
DC-supply
89 7
6 5 11 3
5
Gain
2
+
+
regulation
2
4
15
16 14 ⁺ 4
3
1
+
Telephone
line
microphones. One settable current
limited supply with 6 mA max. current.
• Short start up time.
• Excellent RFI performance.
• 18 - pin DIP and 20 - pin SO packages.
PBL ^{385 41}
1. Impedance to the line and radio interference suppression
2. Transmitter gain and frequency responce network
3. Receiver gain and frequency responce network
4. Sidetone balance network
5. DC supply components
Figure 1. Functional diagram DIP package.
20-pin plastic SO
PBL ^{385 41}
18-pin plastic DIP
1