IL2533

Versatility of the circuit provides possibility of variants selecting on circuit`s pin and several outer

components. It allows adapting easily to the requirements of different standard (post, telephone

and telegraph). Description of circuits` pins is shown at table 1.

La

L

b

Adaptation to line

Power supply generating

Masking on direct current

V

DD

L1

CS

C1

Line current

reading

Soft encrease

LS

Tune generator

Ring frequency

determination

Controlling logic

V

SS

HS/DP

Генератор тона

LLC

R1

STB

AGND

Clock

oscillator

OSC

AGND

LLC Hi

LLC Lo

LLC Off

Keyboard controller

RAM

MFL

Sound

switch

off

LED

RO

M2

M1

R1

R2

R3

R4

С4

С3

С2

С1

Keyboard

MODE

R1

R2

C1

R3

R4

R5

R6

R7

R8

R9

R10

R11

R13

R12

R14

R15

R16

R17

R18

R19

R20

R21

C4

C2

C3

C5

C6

C7

C8

C9

C10

C11

SA1

SA2

SA3

VD1

VD2

VD3

VD4

VD5

VD6

VD9

VD10

VD8

VD7

VT1

VT2

VT3

VT4

Figure 2 – Typical application flow-chat

2