|
|
PDF SA2532K Data sheet ( Hoja de datos )
| Número de pieza | SA2532K | |
| Descripción | SINGLE CHIP TELEPHONE DEMO BOARD | |
| Fabricantes | Sames | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de SA2532K (archivo pdf) en la parte inferior de esta página. Total 27 Páginas | ||
|
No Preview Available !
sames
AN1500A
APPLICATION NOTE
SINGLE CHIP TELEPHONE DEMO BOARD
SA2532K
1 Scope
This application note describes the use of the SA2532K Single Chip Telephone IC developed specifically to meet
with India’s Department of Telecommunication (DOT) Specification for the Electronic Telephone Instruments. This
application note is based on the use of the multi-purpose demo board DB1500I with the SA2532K IC
2 Key Features
• High performance telephone with speech circuit, DTMF/Pulse dialer and tone ringer
• Very few external low cost components
• CMOS technology, far less sensitive to EMC
• EMC proof single sided layout, provision for EMC blocking capacitors installed
• Internally set real AC impedance to reduce external components
• Sidetone programmable by two resistors and one capacitor
• Ring frequency discrimination
• Line loss compensation selectable by jumper
• 2 different flash timings selectable by 2 flash keys
• 31 digit last number redial
• Sliding cursor protocol and pause key
• One-touch repeat dialing
• 1 direct memory
• Tone / Pulse switch
• Modular connectors for handset and line cord, line connector a/b- terminals selectable by jumper
• Layout prepared for 16kHz blocking filters
• 19-key SPST Keyboard on board
• Tone LED output Indicator
• Several hook transistor configurations
• Over-voltage and over-current circuit options
AN1500A
PDS038-SA2532K-001 Rev. C 21-03-00
1 page  
AN1500A
6 General Description
The SA2532K device was developed to provide “plug & play” solution for the Indian DOT, emphasizing high
performance voice transmission and reception. In spite of the fact that voice transmission and reception are the
most vital features in telephony, they are very often ignored or given lower priority compared with some more or
less useless non-voice features. No compromises were accepted during the design phase of the SA2532K, which
is based on the SA2531/2 speech circuit and which supersedes even the hardest PTT requirements worldwide.
The dialler part is based on a long history of producing a wide range of dialer circuits with user-friendly features in
compliance with various national PTT regulations. This knowledge enabled us to develop a specific product to meet
with DOT type approval.
The last piece in the puzzle to complete the full picture of the first CMOS single chip POT was the tone ringer. A
ring frequency discrimination circuit was implemented to avoid false “bell-tinkle” during pulse dialing from a parallel
telephone. The 3-tone melody generator provides the ringing signal.
Note: all the subsequent component numbering is referenced to the AN1500 schematic, shown in pt.22
7 Demo board configuration
The SA2532K is the rare combination of advanced technology and down-to-earth simplicity providing easy and
uncomplicated design effort for the telephone manufacturer. No fussing around: Simply go by the straight forward
guidelines supplied by a highly experienced application group. No technology stress but appealing functionality.
See Fig. 1 for configuration locations:
J1 :Line terminal selection
Sidetone Network
J2: Dial Mode
Selection
Line connector
Handset Connector
J3: line loss compensation
selector
Ringer Capsule
Connector
Fig. 1: Demo board configuration
5/27 sam es
5 Page 
AN1500A
The side tone is probably one of the most important parameters, if not the most important parameter. It determines
very much the overall instinctive performance of a telephone since it has direct influence on other parameters. In a
subjective test the two most inherent parameters are distortion and side tone, or other parameters directly
influenced by those two, e.g. echo, acoustic stability, clearness, etc.
During the design of the SA2532K family considerable effort was put into the system definition of the side tone
cancellation. It was clear that even the highest side tone cancellation could give an unpleasant harsh distortion at
very large signal levels if no efficient limiter was provided. This led to the designing of what turned out to be the
best “soft clipping” circuit yet developed, surpassing any solution used in a telephone so far.
The encounter is a side tone which is easy to calculate and which gives a well defined cancellation virtually
independent of other parameters like return loss (ac impedance) and dynamic range (absolute input signal levels).
12.1 Dual Soft clipping:
The dual soft clipping circuit prevents harsh distortion and acoustic shock in both directions by limiting the
maximum output of the Tx/Rx amplifiers at a level which still maintains a non-distorted signal (see VAGC levels in
data sheet).
If the output of the amplifier is already at the soft clip level and the input level is further increased, then the
amplifier’s gain is reduced, so that the output level remains non-distorted at the soft clip level. Even fast input signal
peaks are detected because of the fast attack time (see tATTACK) of the soft clip circuit. Instabilities are prevented by
using a long decay time (see tDECAY in data sheet).
12.2 Side tone balance network:
The side tone balance network is simply calculated as:
ZBAL = ZLINE x 10
12.3 Example:
For a line termination of
270Ω+750Ω//150nF
the resulting sidetone balance network would be: 2k7 + 7k5//15nF
Within the AN2201 application, this would apply to R13= 2k7
R14= 7k5
C4 = 15nF
13 The Double Wheatstone principle
The family of SA2532K single chip telephones are using a double Wheatstone bridge for return loss and side tone
cancellation. This unique configuration makes it very easy and uncomplicated to set the side tone network.
Fig. 5 explains the principle of the Double Wheatstone bridge: For easier understanding the block diagram is split
into two separate diagrams, which only show the relevant components.
The components shown in the block diagram represent the following components in the DB1500I schematic:
ZLine:
Z1:
Z2:
Zsyn:
Zbal:
Rref,Zref:
the PTT´s AC impedance (external)
R11 = 30Ω
R12 = 300Ω
Q3
the sidetone network
internal resistors
11/27
sames
11 Page | ||
| Páginas | Total 27 Páginas | |
| PDF Descargar | [ Datasheet SA2532K.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| SA2532 | VERSATILE SINGLE CHIP TELEPHONE | Sames |
| SA2532K | SINGLE CHIP TELEPHONE DEMO BOARD | Sames |
| SA2532KA | SINGLE CHIP TELEPHONE FOR INDIA | Sames |
| SA2532KB | SINGLE CHIP TELEPHONE FOR INDIA | Sames |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |