TEA1065 View Datasheet(PDF) - Philips Electronics

Part Name

Description

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TEA1065

Versatile telephone transmission circuit with dialler interface

Philips Electronics 

Philips Semiconductors

Versatile telephone transmission circuit with

dialler interface

Product specification

TEA1065

FUNCTIONAL DESCRIPTION

Supply: VCC, LN, SLPE, REG and STAB

The circuit and its peripherals are usually supplied from the

telephone line. The circuit develops its own supply voltage

at VCC (pin 21) and regulates its voltage drop between LN

and SLPE (pins 1 and 24). The internal supply requires a

decoupling capacitor between VCC and VEE (pin 16); the

internal voltage regulator has to be decoupled by a

capacitor from REG (pin 22) to VEE. The internal current

stabilizer is set by a 3.6 kΩ resistor connected between

STAB (pin 9) and VEE.

The TEA1065 can be set either in a DC voltage regulator

mode or in a DC current regulator mode. The DC mask can

be selected by connecting the appropriate external

components to the dedicated pins (VSI, REFI, DOC,

VBG).

When the DC current regulator mode is not required it can

be cancelled by connecting pin VSI to VEE; pins REFI,

VBG and DOC are left open-circuit.

Voltage regulator mode

The voltage regulator mode is achieved when the line

current is less than the current Iknee as illustrated in Fig.3.

With R13 = R14 = 30 kΩ, the current Iknee = 30 mA

(Ip = 0 mA).

This line current value will be reached when the voltage on

pin VSI (almost equal to the voltage on pin SLPE) exceeds

the voltage on pin REFI (equal to the voltage on pin VBG

divided by the resistor tap R13, R14). For other values of

R13 and R14, the Iknee current is given by the following

formula:

Iknee = ICC + IP + (VBG/R9) × {R14/(R14 + R13)}

− (R15/R9) × IO(VSI)

ICC is the current required by the circuit itself

(typ. 1.14 mA). IP is the current required by the peripheral

circuits connected between VCC and VEE. IO(VSI) is the

output current from pin VSI (typ. 2.5 µA).

The DC slope of the Vline/Iline curve is, in this mode,

determined by R9 (R9 = R9a + R9b) in series with the

rds of the external line current control transistor (see Fig.4;

rds = ∂VGS/∂ID at VGS = VDS).

Current regulator mode

The current regulator mode is achieved when the line

current is greater than Iknee. In this mode, the slope of the

Vline/Iline curve is approximately 1300 Ω with R9 = 20 Ω,

R16 = 1 MΩ, R13 = R14 = 30 kΩ. For other values of

these resistances, the slope value can be approximated by

the following formula:

R9 × {1 + R16 × (1/R13 + 1/R14)}

handbook, full pagewidth

line

current

MBA567

March 1994

Iknee

0

0

voltage

regulator

mode

current

regulator

mode

set

voltage

Fig.3 Voltage and current regulator mode.

5

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