SA541

sames

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FUNCTIONAL OVERVIEW

The SAMES SA54X1 is a family of keypad switchable Loop Disconnect (LD)/Dual Tone

multi-Frequency (DTMF) dialler devices for use in low-cost, dual dialling mode telephone

instruments.

The devices feature automatic storage of a single telephone number of up to 32 digits

for Last Number Redial (LNR) purposes. The low current consumption of the SA54X1

ensures memory retention while powered from the line.

Two modes of operation are available. The first is a LD/DTMF mode which operates

normally in LD mode, but can be switched temporarily via the keypad to DTMF mode

during a call. This mode is intended for applications such as home banking, credit-card

verification and other applications requiring low speed data communications.

The

second mode allows DTMF dialling only.

The Lock function will be described in the Functional Description.

The SA54X1 is pin compatible with SAMES' SA54X5 family of diallers.

Ordering Information

S A 5 4 X 1 X

Lock Option

L:

with (22 pin package)

Blank: without (20 pin package)

On-Hook Current Option

3

5µA @ 2.5V

6

1µA @ 2.5V

9

1µA @ 3V

4

1µA @ 3V (and TBR Period = 300 mSec)

Keypad

R1

R2

R3

R4

C1

C2

C3

Nominal frequency (Hz)

697

770

852

941

1209

1336

1477

Deviation from nominal (%)

-,07

-,10

+,19

-,15

-,17

-,20

-,22

There will be an additional error due to a deviation in the oscillator frequency from 560

kHz.