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FEATURES
Speech circuit, LD/MF Dialler and Tone
Ringer on one 28 pin CMOS chip
Soft clip to avoid harsh distortion
Line Loss Compensation selectable by
pin option
Power down mode
Versatile applications for different PTT
demands
31 digit last number redial
Sliding Cursor protocol with comparison
2 Flash keys, 100 ms and 280 ms (option
600 ms)
Pause key for 3 sec Auto Pause or Wait
Function
GENERAL DESCRIPTION
The SA2532 is a CMOS integrated circuit that
contains all the functions needed to form a
high performance electronic telephone.
The device incorporates LD/MF dialling,
melody generation, ring frequency discrimi-
nation and a high quality speech circuit.
A RAM is on chip for a 31 digit last number
redial. The sliding cursor procedure makes
Last Number Redial easy behind a PABX.
The versatility of the circuit is provided by on
chip programmability and a few external com-
ponents. This allows easy adaption to differ-
ent PTT requirements without changing the
PCB of the telephone.
4153
VERSATILE SINGLE CHIP TELEPHONE
Ring frequency discrimination
Operating range from 13 to 100 mA
(down to 5 mA with reduced perform-
ance)
Low noise (max. -72dBmp)
Real or Complex impedance on chip pro-
grammable
LD/MF switchable dialling
On chip MF filter (CEPT CS 203 compat-
ible)
3-tone melody generator with selectable
repetition rates
PACKAGE
Available in 28 pin DIP and SOIC
SA2532 A/C/U
LS
1
RO2
RO1
V
DD
A GND
STB
CI
SA2532
MO
LLC
HS DP
OSC
RR
C4
C3
14
DR-00975
PDS039-SA2532-001
SA2532
RI
28
LI
V
SS
CS
M2
M1
MODE
FCI
R1
R2
R3
R4
C1
C2
15
1/22
1/22
Rev. C
23-10-1995
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Table of Contents
Summary of Contents for Sames SA2532
- Page 1 Function PACKAGE GENERAL DESCRIPTION Available in 28 pin DIP and SOIC The SA2532 is a CMOS integrated circuit that contains all the functions needed to form a high performance electronic telephone. The device incorporates LD/MF dialling, melody generation, ring frequency discrimi- nation and a high quality speech circuit.
-
Page 2: Pin Description
SA2532 PIN DESCRIPTION Pin# Symbol Function Microphone Inputs Differential inputs for the microphone (electret). Receiver Outputs These are the outputs for driving a dynamic earpiece with an impedance of 100 to 300Ω Analog Ground This is the analog ground for the amplifiers. -
Page 3: Functional Description
Oscillator All the Timing Functions of the SA2532 are based on a Clock Frequency of 3.58MHz. A crystal or ceramic resonator of this frequency should be connected to the OSC pin. In practise minor deviations from the nominal frequency may occur due to the characteristics of the frequency reference device used and so it is recommended that care is taken in the selection of components. - Page 4 SA2532 Receive The receive input is the differential signal of RI and STB. The gain of the receive path is 2 dB (test circuit figure 5) with differential outputs, RO1/RO2 (0dB on SA2532C/U). When mute is active during dialling the gain is reduced by > 60dB. During DTMF dialling a MF comfort tone is applied to the receiver.
- Page 5 Dialling Functions Valid Keys The keypad of the SA2532 comprises a maximum of 20 keys (of which 3 have no function). A Bi-polar scan technique is used so that the 20 keys are scanned in a 4 x 5 matrix using only 8 pins.
- Page 6 SA2532 Sliding Cursor Procedure To accommodate easy and uncomplicated redialling (LNR) behind a PABX, a sliding cursor protocol is implemented. If new entries match the previous RAM contents, pressing the LNR key will dial out the remaining digits. If there is an error in matching, the LNR will be inhibited until next on-hook, and the RAM will contain the new number.
- Page 7 The keypad Row and Column Pins can readily be driven by a Microcontroller Interface. When configured in this way the SA2532 inputs and dials the corresponding digits in either LD or DTMF. The LNR store can be used to buffer digits to allow high speed data entry. See Application Note AN3002A for details.
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Page 8: Typical Application
SA2532 TYPICAL APPLICATION Only the components necessary for presenting the complete functions of the SA2532 are included. FIGURE 3 8/22... - Page 9 SA2532 FEATURE PHONE APPLICATION Only the components necessary for presenting the complete functions of the SA2532 are included. FIGURE 4 9/22...
-
Page 10: Operating Procedures
SA2532 OPERATING PROCEDURES Procedure Principles The procedures for utilizing the features of the SA2532 are optimized out of consideration for the human factor in order to: meet the user’s expectations be easy to learn and relearn not invoke any automatic functions which the user doesn’t expect protect the user from committing critical errors, e.g. - Page 11 SA2532 Privacy Mute 11/22...
- Page 12 SA2532 Temporary MF FIFO Pressing any other key does not change the state. EXIT FIFO 12/22...
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Page 13: Timing Diagrams
SA2532 TIMING DIAGRAMS LD Dialling LD Dialling with Access Pause MF Dialling 13/22... -
Page 14: Electrical Characteristics
SA2532 Flash ELECTRICAL CHARACTERISTICS Absolute Maximum Ratings ≤7V Positive Supply Voltage ..................-0.3V≤V Input current ........................±25mA ≤10V Input Voltage (LS) ....................-0.3V≤V ≤8V Input Voltage (LI, CS) ................... -0.3V≤V ≤V Input Voltage (STB, RI) ................-2V≤V +0.3V ≤35V Input Voltage (MO) ..................... -0.3V≤V ≤V... - Page 15 SA2532 AC Characteristics (I =15mA;f=800Hz unless otherwise specified) LINE Symbol Parameter Conditions Units Transmit Test Circuit Fig.5 Gain (M1/M2) =600Ω = 1000Ω 36.5 Variation with Frequency f=500Hz to 3.4kHz ±0.8 TX/F ≤0.5V Distortion Soft Clip Level PEAK Soft Clip Overdrive Attack Time µs/6dB...
- Page 16 SA2532 AC Characteristics (cont’d) (I = 15 mA;f=800Hz unless otherwise specified) LINE Symbol Parameter Conditions Max Units Receive Test Circuit Fig.5 Receive Gain (RO1/RO2) Z =600Ω =1000Ω -0.2 ∆A Variation with Frequency f=500 Hz to 3.4 kHz ±0.8 RX/F ≤0.5V...
- Page 17 SA2532 AC Characteristics Cont'd Symbol Parameter Conditions Units Tone Rise Time Note 2 Tone Fall Time Note 2 Dial Rate ±5% Make/Break Period ±5%, MODE=low 40.8/61.2 ±5%, MODE=high 33/66 Pre-Digit Pause Inter Digit Pause Mute Overhang Flash Duration 1 Flash Duration 2...
- Page 18 SA2532 Note 1: The values are valid during automatic dialling and are minimum values during manual dialling, i.e. the tones will continue as long as the key is depressed. Note 2: The rise time is the time from 10% of final value until the tone amplitude has reached 90% of its final value.
- Page 19 SA2532 Test Circuit Figure 5 19/22...
- Page 20 SA2532 Ordering Information: Versions DTMF Access Package (ohm) Level Period Pause SA2532A P -6/-8dBm 280ms 28 pin DIP SA2532A S -6/-8dBm 280ms 28 pin SOIC SA2532C P 1000 -6/-8dBm 280ms 28 pin DIP SA2532C S 1000 -6/-8dBm 280ms 28 pin SOIC...
- Page 21 SA2532 NOTES: 21/22...
- Page 22 Disclaimer: The information contained in this document is confidential and proprietary to South African Micro- Electronic Systems (Pty) Ltd ("SAMES) and may not be copied or disclosed to a third party, in whole or in part, without the express written consent of SAMES. The information contained herein is current as of the date of publication;...