AMSCO AS2525

Preliminary
AS2525
Single-Chip Handsfree Phone
CMOS Integrated Circuit
Austria Mikro Systeme International AG
General Description
Key Features
The AS2525 is a CMOS mixed-mode integrated
circuit for use in feature phones, answering machines
and fax machines. It contains an analogue line
interface and speech circuit for a/b terminals,
loudhearing, handsfree, enhanced LD/MF dialler, tone
ringer with dc/dc converter and serial interface to
EEPROM and LCD-driver (AS2591), all in a 44 pin
package. The circuit is fully line powered.
q Line/speech handsfree circuit, LD/MF repertory
dialler, and tone ringer on one 44 pin CMOS chip
q Operating range from 15 to 100 mA line current
(down to 5 mA with slightly reduced performance)
q All significant parameters programmable with
external EEPROM
q Volume control of receiver signal
The AS2525 uses an external EEPROM for a 31 digit
last number redial storage and memories for 26
numbers each containing up to 21 digits/data.
q Handsfree function with enhanced voice switching
q Low noise (max. -72 dBmp)
q Unique EMC performance
The device provides a volume control for the earpiece
and the loudspeaker. The volume can be controlled by
pressing the [V-]/[V+] keys.
q LD/MF switchable dialling with temporary MF
mode
q Repertory dialling with last number redial and
memory dialling (8 x 2 direct and 10 indirect)
The versatility of the circuit is provided by
programming all parameters through an external
EEPROM. This allows easy adaptation to various PTT
requirements worldwide.
q Call restriction with PIN code
q Serial interface for EEPROM and LCD driver
Package
q 2-tone/3-tone ringer with ring frequency detection
Available in 44 pin TQFP.
Block Diagramme
LS
30 Ω
LI
AS2525
V DD
FT2
AGND
VDD
LINE
SENSE
CBN
FT1
M1
A GND
VREF
SUPPLY
V DD
NOISE
DET.
+
M2
CS
–
–
+
M3
SS
+
AGND
PEAK
DET.
M4
V PP
V PP
V SS
V DD
–
V SS
+
VOICE
SWITCHING
V PP
CI
LO1
PEAK
DET.
300 Ω
RI
–
LO2
+
V SSA
STB
RECI
ZBAL
HS
HF
RECV
DTMF
MELODY
DEBOUNCE
DM/HM
RO
FCI
DPN
CPU
DIALLER
KEYSCANNING
OSCILLATOR
LED
DI DO CLK
Rev. 1.3
CS1 CS2
KEYBOARD (C1-4/R1-3)
Page 1
3.58
MHz
DC/DC
CONVERTER
CM
May 1999
Preliminary
AS2525
Pin Description
Pin #
Symbol
Type
Description
1
CS2
DO
Chip Select 2
Chip select signal for external LCD driver circuit or 2 mA LED
If signal is not activated, a pull down resistor ( 100 kΩ ) is inserted.
2
DPn
DO
Dial Pulse Output
Digital output which holds the line during off-hook operation or pulls low during
break periods of pulse dialling and flash.
3
HF
DI
HandsFree Switch Input
This is an Schmitt-trigger input that is pulled high to enable handsfree
operation.
4
HS
DI
HandSet Switch Input
This is an Schmitt-trigger input that is pulled high by the hook switch to enable
handset or headset operation.
5
FT1
AI
Analogue input pin for connecting a capacitor for offset cancellation.
6
FT2
AI
Analogue input pin for connecting a capacitor for offset cancellation.
7
M4
AI
Microphone Input 4
Differential input for the handsfree microphone (electret).
8
M2
AI
Microphone Input 2
Differential input for the handset microphone (electret).
9
M3
AI
Microphone Input 3
Differential input for the handsfree microphone (electret).
10
M1
AI
Microphone Input 1
Differential input for the handset microphone (electret).
11
STB
AI
Side Tone Balance Input
Analogue input for side tone cancellation network.
12
CS
AO
13
VSS
Supply
14
LI
AI
Current Shunt Control Output
N-channel open drain output to control the external high power shunt transistor
for synthesising ac- and dc-impedance, modulation of line voltage and shorting
the line during make periods of pulse dialling.
Voltage Source Source
Negative Power Supply.
Line Input
Analogue input used for power extraction and line current sensing.
15
RI
AI
Receive Input
Analogue input for ac-separated receive signal.
16
SS
AO
Supply Source Control Output
N-channel open drain output to control the external high power source
transistor for supplying (Vpp) the loudspeaker amplifier in off-hook
loudspeaking/handsfree mode.
17
LS
AI
Line Current Sense Input
Analogue input for sensing the line current.
Rev. 1.3
Page 2
May 1999
Preliminary
AS2525
Pin #
Symbol
Type
Description
18
CI
AI
Complex Impedance Input
Analogue input pin for the capacitor to program a complex impedance.
19
RECI
AI
RECeive Input
Analogue input for the handsfree receive path. Should be connected to RO via
a coupling capacitor.
20
RECV
AI
RECeive Voice Switching Input
Analogue input for receive voice switching path.
21
RO
AO
Receive Output to Handset
Output for driving a dynamic earpiece with an impedance from 150 Ω to 300 Ω.
22
VDD
Supply
Voltage Drain Drain
Positive Power Supply.
23
AGND
Supply
24
CBN
AI
Analogue input pin for connecting a capacitor for background noise monitoring.
25
CM
DO
Converter Make Output
This is an output for controlling the external switching converter. During ringing
it converts the ring signal into a 4V supply voltage.
26
VPP
Supply
27
28
LO1
LO2
AO
29
VSSA
Supply
30
DM/HM
DI
Dial Mode/Headset Mode Switch Input
Digital input for choosing between LD and MF dialling or choosing handset and
headset mode. See “Table 3: Parameter settings” for further details. This pin is
scanned after manual off-hook only.
31
FCI
DI
Frequency Comperator Input
Analogue Ground
Special ground for the internal amplifiers.
Loudspeaker Power Supply
High power supply for the output driver stage.
Loudspeaker Outputs 1/2
Output pins for a 32 Ω ( 25 to 50 Ω ) loudspeaker.
Power supply pin for LO1-LO2 output amplifier.
This is a Schmitt-trigger input for ring frequency discrimination. Disabled during
off-hook.
32
LED
DO
33
OSC
34
35
36
R1
R2
R3
DI/O
Keyboard Rows
(see Figure 4: Keyboard Layout).
37
38
39
40
C1
C2
C3
C4
DI/O
Keyboard Columns
(see Figure 4: Keyboard Layout).
41
CLK
DO
Clock
LED Output
Digital output for connecting 2 mA LED to indicate handsfree mode.
Oscillator Input
Input for ceramic resonator 3.58 MHz.
Clock output for 3-wire bus.
If signal is not activated, a pull down resistor (100 kΩ) is inserted.
Rev. 1.3
Page 3
May 1999
Preliminary
AS2525
Pin #
Symbol
Type
42
DI
DI
Data Input
Data input of 3-wire bus.
If signal is not activated, a pull down resistor (100 kΩ) is inserted.
43
DO
DO
Data Output
Data output of 3-wire bus.
A 100 kΩ resistor connected from this pin to VSS enables key locking.
If signal is not activated, a pull down resistor (100 kΩ) is inserted.
44
CS1
DO
Chip Select 1
Chip select signal for external EEPROM.
If signal is not activated, a pull down resistor (100 kΩ) is inserted.
DI:
DO:
DI/O:
Description
Digital Input
Digital Output
Digital Input/Output
AI:
AO:
AI/O:
Pin Configuration
YYWWAAA
AS2525
Austria
Keyboard Layout
33
32
31
30
29
28
27
26
25
24
23
OSC
LED
FCI
Head
VSSA
LS2
LS1
VPP
CM
CBN
AGND
C1
C2
C3
1
2
4
5
6
PG
VM2
M6
7
8
9
R/P
MT
M3
M7
3
MR
V+
M1
M5
C4
∗
0
#
FL
SH
M4
M8
R1
R2
R3
Figure 4: Keyboard Layout
Maximum RON for key closure: 1 kΩ
Minimum ROFF for open key: 1 MΩ
CS
VSS
LI
RI
SS
LS
CI
RECI
RECV
RO
VDD
12
13
14
15
16
17
18
19
20
21
22
CS2 1
DPn 2
HF 3
HS 4
FT1 5
FT2 6
M4 7
M2 8
M3 9
M1 10
STB 11
Analogue Input
Analogue Output
Analogue Input/output
See “Table 1: Key definitions” for description of key
functions.
Figure 3: Pin configuration
Basic Definitions
Password is set to 0123 and is used to access basic parameter settings (see Table 3: Parameter settings). The
set-up programming is normally done in the factory during manufacturing of the telephone sets. The factory
settings can be loaded into the EEPROM (see Figure 6: Memory allocation for external EEPROM).
PIN code is default set to 1111 and is used by the user to protect certain user settings (see Table 5: User
programming with PIN code). The PIN code can be changed by the user.
Default settings are shown in bold.
Program procedures are entered with the [PG] key. Pressing any invalid key or going on-hook during programming
will abort the program mode and no changes will be stored. Ending a program procedure by pressing the [PG] key
will store the changes and exit the program mode.
Rev. 1.3
Page 4
May 1999
Preliminary
AS2525
Key Definitions and Procedures
Table 1: Key definitions
Key
Condition
Function
Remark
[0] - [9],
[#], [∗]
Off-hook
Digits
Function depending on mode
[∗]
LD mode
Temporary MF select
Providing mixed mode dialling (default LD
selected)
Speech mode
Enter programme state
To enter the programme state
Programme mode
Exit programme state
To terminate/exit programme state
Speech mode
Enter mute state
To enter mute state
Mute state
Exit mute state
To terminate/exit mute state
Programme mode
Enter blank
To enter blank digit during programming
Redial/Pause
Allows re-signalling of the last dialled number and
insertion of pauses
Pause
Each key pressure inserts a pause
Flash function
Invokes a timed loop break
[PG]
[MT]
[R/P]
Programme state
[FL]
[V+]
Speech mode
Volume control
To increase the receive gain
[V-]
Speech mode
Volume control
To increase or decrease the receive gain
Memory redial key
To access memory by key codes
Memory dial
Access keys to memories 1 to 8 and 9 to 16
Second function (shift)
To access second function of keys
[MR]
[M1] - [M8]
[SH]
Table 2: Digits
Digit Key
DTMF Mode
(fLOW + fHIGH)
Pulse Mode
[0]
941 + 1336 Hz
10 pulses
[1]
697 + 1209 Hz
1 pulse
To enter PIN protected programming
Memory 18
[2]
697 + 1336 Hz
2 pulses
Select flash duration
Memory 19
[3]
697 + 1477 Hz
3 pulses
Select dialling mode
Memory 20
[4]
770 + 1209 Hz
4 pulses
Select pause duration
Memory 21
[5]
770 + 1336 Hz
5 pulses
Key lock toggle
Memory 22
[6]
770 + 1477 Hz
6 pulses
Ringer volume
Memory 23
[7]
852 + 1209 Hz
7 pulses
Ringer melody
Memory 24
[8]
852 + 1336 Hz
8 pulses
LCD contrast
Memory 25
[9]
852 + 1477 Hz
9 pulses
Ringer on/off
Memory 26
[∗]
941 + 1209 Hz
Temporary MF select
-
[#]
941 + 1477 Hz
-
-
Rev. 1.3
Programming Mode
([PG] + Digit)
Memory Location
([MR] + Digit)
Memory 17
Page 5
May 1999
Preliminary
AS2525
Table 3: Parameter settings
Parameter
Symbol
Procedure:
[PG] + [0] + (Password) +
Default
Options
Inter-Digit Pause (LD)
IDP
[∗] + [1] + [HEX code]
840 ms
1.72 ms … 7.03 sec. (see Table 4)
MF Tone Duration
TD
[∗] + [2] + [HEX code]
82 ms
1.72 ms … 7.03 sec. (see Table 4)
MF Inter-Tone Pause
ITP
[∗] + [3] + [HEX code]
82 ms
1.72 ms … 7.03 sec. (see Table 4)
Flash 1 Duration
FL1
[∗] + [4] + [HEX code]
101 ms
1.72 ms … 7.03 sec. (see Table 4)
Flash 2 Duration
FL2
[∗] + [5] + [HEX code]
285 ms
1.72 ms … 7.03 sec. (see Table 4)
Pause 1 Duration
P1
[∗] + [6] + [HEX code]
1 second
1.72 ms … 7.03 sec. (see Table 4)
Pause 2 Duration
P2
[∗] + [7] + [HEX code]
3 seconds
1.72 ms … 7.03 sec. (see Table 4)
Pre-Digit Pause (LD)
PDP
[∗] + [8] + [HEX code]
33 ms
1.72 ms … 7.03 sec. (see Table 4)
Post Flash Pause
PFP
[∗] + [9] + [HEX code]
274 ms
1.72 ms … 7.03 sec. (see Table 4)
Tx Gain, Handset
ATX-HS
[0] + [1] + [HEX code]
37 dB
30 to 45 dB (see Table 8)
Rx Gain, Handset
ARX-HS
[0] + [2] + [HEX code]
1 dB
-6 to 9 dB (see Table 12)
Tx Gain, Handsfree
ATX-HF
[0] + [3] + [HEX code]
46 dB
39 to 54 dB (see Table 10)
Rx Gain, Loudspeaker
ARX-HS
[0] + [4] + [HEX code]
29 dB
22 to 37 dB (see Table 14)
Line Loss
Compensation
LLC
[0] + [5] +
[0] = off
[1] = range 1: ILINE = 20 - 50 mA
[2] = range 2: ILINE = 45 - 75 mA
DTMF Level (Low
Group)
VMF
[0] + [6] + [HEX code]
-6 dBm
-18 to -6 dBm in 1 dB steps
(see Table 24)
Tx Gain, Headset
ATX-HEAD
[0] + [7] + [HEX code]
37 dB
30 to 45 dB (see Table 20)
Rx Gain, Headset
ARX-HEAD
[0] + [8] + [HEX code]
1 dB
-6 to 9 dB (see Table 21)
MF Comfort Tone, RO
VMF-CT/RO
[0] + [9] + [HEX code]
-30 dBr
-36 to -18 dBr in 6 dB steps
(see Table 30)
MF Comfort Tone,
LO1/2
VMF-CT/LO
[0] + [0] + [HEX code]
-9 dBr
-15 to 3 dBr in 6 dB steps
(see Table 30)
Make/Break Ratio
(LD)
M/B
[#] + [1] +
[1] = 2 : 3
[0] = 1 : 2
Dial Rate (LD)
DR
[#] + [2] +
[0] = 10 pps
[1] = 20 pps
DC Mask (LI Voltage)
VLI
[#] + [3] +
[1] = 4.5 Volt
[0] = 3.5 Volt
Tx Soft Clip (Handset)
[#] + [4] +
[1] = on
(2 VPEAK)
[0] = off
Rx Soft Clip (Handset)
[#] + [5] +
[1] = on
(1 VPEAK)
[0] = off
Noise Monitoring (HF)
[#] + [6] +
[1] = on
[0] = off
Loudhearing Mode
[#] + [7] +
[1] = HF only
[0] = LH and HF modes available
Ringer Melody
[#] + [8] +
[1] = 3-Tone
[0] = 2-Tone
[#] + [9] +
[1] = on
[0] = off
[#] + [0] +
[1] = 1111
Selected by user
Key-in Tone (Beep)
Reset PIN Code
Rev. 1.3
KT
Page 6
May 1999
Preliminary
AS2525
Parameter
Symbol
Procedure:
[PG] + [0] + (Password) +
Default
Options
Flash 1 During LD
[#] + [∗] +
[1] = on
[0] = off
Flash 2 During LD
[#] + [#] +
[0] = off
[1] = on
Extended LCD
Symbols
[9] + [1] +
[0] = off
[1] = on
Tx Soft Clip,
Handsfree
[9] + [2] +
[1] = on
[0] = off
Rx Soft Clip,
Handsfree
[9] + [3] +
[1] = on
[0] = off
Voice Switching,
Speed
[9] + [4] +
[1] = x 2
[0] = x 1; [2] = x 4; [3] = x 8
Handset/Headset
Volume
[9] + [5] +
[1] = reset by
on/off-hook
[0] = setting is maintained
LCD Test
[9] + [6]
Turns on all segments, pressing any further key
turns on all digits “1” and all symbols off.
Temporary MF by ∗
with tone
[9] + [7] +
[0] = off
[1] = on
Key Lock Function
[9] + [8] +
[1] =
available
[0] = not available
[9] + [9] +
[1] = MF/LD
[0] = Handset/Headset
Ringer Off Function
[9] + [0] +
[1] =
available
[0] = not available
Key Test
[9] + [∗] +
Any key pressure turns the LED on
Volume Control on
Handset
[9] + [#] +
[1] = enabled
Pin Select “DM/HM”
DM/HM
[0] = disabled
The above parameters are programmable using a password (0123) through external EEPROM. All procedures
must be terminated by pressing the [PG] key. Software for factory settings is available on request.
The programming of timings is done by using a HEX data code as follows:
C1
C2
C3
1
2
4
5
6
7
8
9
3
C4
0
Table 4: Timing selection by HEX code
R1
Parameter
Default
HEX
Binary Data
R2
Inter-digit pause
840 ms
E17
1111 0001 0111
R3
Tone duration
82 ms
FD0
1111 1101 0000
Inter-tone pause
82 ms
FD0
1111 1101 0000
Flash 1
101 ms
FC4
1111 1100 0100
Flash 2
285 ms
F5A
1111 0101 1010
Pause 1
1 sec
DB9
1101 1011 1001
Pause 2
3 sec
92C
1001 0010 1100
Post-digit pause
33 ms
FED
1111 1110 1101
Post-flash pause
274
F60
1111 0110 0000
A (M1) B (M2) C (M3) D (M4)
E (M5) F (M6)
Figure 5: Keys for HEX-code entry
Data = 4096 - (fOSC /(512∗12) ∗ T
(T = Time; fOSC = 3.58 MHz)
Rev. 1.3
Page 7
May 1999
Preliminary
AS2525
Table 5: User programming with PIN code
Function
Symbol
Procedure
Options
Call Restriction 1
CR1
[PG] + [1] + (PIN) + [∗] + [1] +
Key in two digits, use [MT] for blank
Call Restriction 2
CR2
[PG] + [1] + (PIN) + [∗] + [2] +
Key in two digits, use [MT] for blank
Key Lock
[PG] + [1] + (PIN) + [#] + [6] +
[0] = unlocked and [1] = locked
Clear All Memories
[PG] + [1] + (PIN) + [#] + [7] +
Press [1] to clear
Reset To Factory
Settings
[PG] + [1] + (PIN) + [#] + [8] +
Press [1] to reset
[PG] + [1] + (PIN) + [0] +
Key in new PIN + new PIN
Change PIN Code
PIN
Press [PG] to store setting and terminate procedure
Table 6: Mode programming
Function
Symbol
Procedure
Options
Select Flash
FL
[PG] + [2] +
[0] = Flash 1 and [1] = Flash 2
Select Dialling Mode
DM
[PG] + [3] +
[0] = LD (pulse) and [1] = MF (DTMF)
P
[PG] + [4] +
[0] = Pause 1 and [1] = Pause 2
Easy Key Lock
[PG] + [5] + [3] + [9]
Toggles between locked and unlocked
Ringer Volume
[PG] + [6] +
[1] = -16 dB, [2] = -7 dB, and [3] = 0 dB (maximum)
Ringer Melody
[PG] + [7] +
[0], [1], [2], [3], or [4]
[PG] + [8] +
[1], [2], or [3] (see also AS2591 data sheet)
[PG] + [9] +
[0] = Off and [1] = On
Select Pause Time
LCD Contrast
V33
Bell On/Off
Press [PG] to store setting and terminate procedure
Memory Allocation
The EEPROM memory consists of three areas:
A = factory settings; B = user settings; C = stored numbers
EEPROM
A) factory settings
programmed in factory
Set-up programming
"reset to factory settings"
B) user settings
User-code programming
…write/read by AS2525
C) stored numbers
Figure 6: Memory allocation for external EEPROM
The AS2525 is writing and reading to and from area B and C during normal operation and user-code programming.
Area A is protected during normal operation and contains a back-up copy of the factory settings. This back-up copy
can be loaded into area B by the user with the user-code programming procedure "reset to factory settings". The
only way to change the factory settings in area A is by set-up programming using password. After changing area A
by set-up programming, the AS2525 automatically performs a "reset to factory settings" to load this changes also
into area B.
Rev. 1.3
Page 8
May 1999
Preliminary
AS2525
Functional Description
Side-Tone
DC Conditions
A good side-tone cancellation can be achieved by
using the following equation:
The normal operating mode is from 15 mA to 100 mA.
An operating mode with reduced performance is from
5 mA to 15 mA. In the line-hold range from 0 mA to 5
mA the device is in a power down mode.
The dc characteristic is determined by the voltage at
LI pin and a 30 Ω resistor between pin LI and LS. It
can be calculated by the following equation:
ZBAL/ZLINE = 10
This is assuming that the side-tone reference resistor,
R2 (between LI and STB) is 300 Ω and R1 is 30 Ω.
R1 = 30 ohm
ZLINE
VLS = VLI + ILINE ∗ 30 Ω
ZBAL
VLI can be programmed to be 3.5 V or 4.5 V.
Table 7: DC mask selection
Figure 8: Side-tone balance
[PG] + [0] + (Password) + [#] + [3] + (digit) + [PG]
Digit
R2 = 300 ohm
Transmit Path
DC Mask (dc voltage at pin LI)
[0]
Low dc mask, VLI = 3.5 Volt
[1]
High dc mask, VLI = 4.5 Volt
The gain of the M1/M2 —> LS path is default set to
37 dB. This gain can be changed from 30 dB to 45 dB
in 1 dB steps by set-up programming.
Table 8: Handset Tx gain setting
[PG] + [0] + (Password) + [0] + [1] + (x) + [PG]
VLine
8
(V)
Key
(x)
Tx Gain (dB)
M1/2 to LS
Key
(x)
Tx Gain (dB)
M1/2 to LS
[0]
[1]
[2)
[3]
[4]
[5]
[6]
[7]
30
31
32
33
34
35
36
37
[8]
[9]
[M1]
[M2]
[M3]
[M4]
[M5]
[M6]
38
39
40
41
42
43
44
45
VLS
6
4
VLI
2
0
0
20
40
60
80
ILine
(mA)
100
Figure 7: DC characteristic with low dc mask
2/4 Wire Conversion
AS2525 has a built-in dual Wheatstone bridge with
one common ground. This provides a maximum of
independence of ac impedance and side-tone from
each other. One can adapt side-tone without changing
the ac impedance.
The input is differential with an impedance of 10 kΩ.
The soft clip circuit limits the output voltage swing at
pin LS to 2 VPEAK when activated.
Table 9: Handset Tx soft clipping selection
[PG] + [0] + (Password) + [#] + [4] + (digit) + [PG]
Digit
Handset Tx Soft Clipping
AC Impedance
[0]
Disabled
The ac impedance of AS2525 is set to 1000 Ω. A
complex impedance can be adjusted by connecting an
external capacitor to the CI pin. With an external
resistor of approximately 1.5 kΩ connected to the LS
pin, it can be programmed to 600 Ω.
[1]
Enabled (2 VPEAK)
ZAC(syn) = 33 ∗ 30 Ω
Rev. 1.3
There is optional LLC for this path.
The gain of the M3/M4 —> LS path is default set to
46 dB. This gain can be changed from 39 dB to 54 dB
in 1 dB steps by set-up programming.
Page 9
May 1999
Preliminary
AS2525
voltage at RO to 1 VPEAK. It prevents harsh distortion
and acoustic shock.
Table 10: Handsfree Tx gain setting
[PG] + [0] + (Password) + [0] + [3] + (x) + [PG]
Key
(x)
Tx Gain (dB)
M3/4 to LS
Key
(x)
Tx Gain (dB)
M3/4 to LS
[0]
[1]
[2]
[3]
[4]
[5]
[6]
[7]
39
40
41
42
43
44
45
46
[8]
[9]
[M1]
[M2]
[M3]
[M4]
[M5]
[M6]
47
48
49
50
51
52
53
54
Table 13: Handset Rx soft clipping selection
[PG] + [0] + (Password) + [#] + [5] + (digit) + [PG]
Digit
Handset Rx Soft Clipping (Earpiece)
[0]
Disabled
[1]
Enabled
There is LLC option for this path.
The gain of the LS —> LO1/LO2 receive path is set to
29 dB.
The input is differential with an impedance of 10 kΩ.
The soft clip circuit limits the output voltage swing at
pin LS to 2 VPEAK when activated.
This gain can be changed by set-up programming
from 22 dB to -37 dB in 1 dB steps.
Table 11: Handsfree Tx soft clipping selection
Table 14: Loudspeaker gain setting
[PG] + [0] + (Password) + [0] + [4] + (x) + [PG]
[PG] + [0] + (Password) + [9] + [2] + (digit) + [PG]
Digit
Handfree Tx Soft Clipping
[0]
Disabled
[1]
Enabled (2 VPEAK)
There is no LLC option for this path.
Receive Path
The gain of the LS —> RO receive path is default set
to 1 dB. This gain can be changed from -6 dB to 9 dB
in 1 dB steps by set-up programming.
Table 12: Handset Rx gain setting
[PG] + [0] + (Password) + [0] + [2] + (x) + [PG]
Key
(x)
Rx Gain (dB)
LS to RO
Key
(x)
Rx Gain (dB)
LS to RO
[0]
[1]
[2]
[3]
[4]
[5]
[6]
[7]
-6
-5
-4
-3
-2
-1
0
1
[8]
[9]
[M1]
[M2]
[M3]
[M4]
[M5]
[M6]
2
3
4
5
6
7
8
9
Rx Gain (dB)
LS to LO1/2
Key
(x)
Rx Gain (dB)
LS to LO1/2
[0]
[1]
[2]
[3]
[4]
[5]
[6]
[7]
22
23
24
25
26
27
28
29
[8]
[9]
[M1]
[M2]
[M3]
[M4]
[M5]
[M6]
30
31
32
33
34
35
36
37
The user can also change the gain using the [V+]/[V-]
keys (see section "Handsfree"). The volume range is
15 dB (-7/+8 dB).
The receive input is the differential signal of RI and
STB. The soft clip circuit limits the output voltage
swing at LO1/LO2 to 1 VPEAK.
Table 15: Loudspeaker soft clipping selection
[PG] + [0] + (Password) + [9] + [3] + (digit) + [PG]
Digit
The user can also change the gain within this range in
4 dB steps via the [V+]/[V-] keys. The receive default
gain in handset and headset mode must lie between
position 5 and 9 for correct operation of the volume
control. The receive input is the differential signal of
RI and STB. The soft clip circuit limits the output
Rev. 1.3
Key
(x)
Handfree Rx Soft Clipping (Loudspeaker)
[0]
Disabled
[1]
Enabled
There is optional LLC for this path.
Line Loss Compensation (LLC)
The line loss compensation is set-up programmable
and effects only the handset mode.
Page 10
May 1999
Preliminary
AS2525
attenuation scheme) shows how voice switching is
controlled.
Table 16: Line loss compensation selection
[PG] + [0] + (Password) + [0] + [5] + (digit) + [PG]
Digit
LLC Range
[0]
No LLC (gain independent of line current)
[1]
-1 dB/5 mA from 20 to 50 mA
[2]
-1 dB/5 mA from 45 to 75 mA
voice switching circuit
TX_atten
Voice
switching
RX
When it is activated, the transmit and receive gains for
both channels are decreased by 6 dB at line currents
from 20 mA to 50 mA or from 45 mA to 75 mA
depending on selected range.
Handsfree
speech
Backgnd
noise
monitor
Figure 9: Handsfree voice switching
The handsfree function allows voice communication
without using the handset (full 2-way speaker phone).
Two voice controlled attenuators prevent acoustic
coupling between the loudspeaker and the handsfree
microphone.
A background monitoring circuit is incorporated. This
circuit can be enabled/disabled as required.
Table 17: Background noise monitoring selection
[PG] + [0] + (Password) + [#] + [6] + (digit) + [PG]
The voice switching circuit has three states, namely
idle, transmit or receive. In receive mode the
attenuation of the receive path and the transmit path
can be controlled by the volume keys between 0 dB
and -15 dB. The following table (Table 18: Handsfree
Digit
Background Noise Monitoring
[0]
Disabled
[1]
Enabled
Gmax = +9dB
Gmin = -21dB … -40dB (VOL)
LINE
+23dB
+14dB
+8dB
Offset
comp
Compress
Peak
detector
+3dB
speech
Voice
switching
FT2
Peak
detector
Compress
Offset
comp
CTXoffset
RO
FT1
CBN
RECV
Offset
comp
Compress
Peak
detector
Cmicoffset
CBckgnd
RECI
Gmax = -4dB … +16dB (VOL)
Gmin = -33dB
+12dB
Figure 10: Signal path of handsfree circuit
Rev. 1.3
Page 11
May 1999
Preliminary
AS2525
Table 18: Handsfree attenuation scheme
Speech
Mode
RX-gain
TX-gain
Remark
RX > TX_atten
X
Receive
0 dB to -20 dB
-50 dB to -30 dB
adjustable with [V+]/[V-] keys in 8
steps
TX_atten > RX
No
Idle
-25 dB
-25 dB
middle position
TX_atten > RX
Yes
Transmit
-50 dB
0 dB
independent of [V+]/[V-] keys
IDLE-mode
RX-mode
TX-mode
0dB
-10dB
TX-gain
-20dB
Vol max
Vol default
Vol min
-25dB
-30dB
RX-gain
-40dB
-50dB
Figure 11: Gain transition of voice switching
Table 20: Headset Tx gain setting
Loudhearing
A loudhearing mode can be enabled/disabled through
the set-up programming.
Table 19: Loudhearing mode selection
[PG] + [0] + (Password) + [#] + [7] + (digit) + [PG]
Digit
Loudhearing
[0]
Enabled (LH + HF provided)
[1]
Disabled (only HF is provided)
Headset mode
[PG] + [0] + (Password) + [0] + [7] + (x) + [PG]
Key
(x)
Tx Gain (dB)
M1/2 to LS
Key
(x)
Tx Gain (dB)
M1/2 to LS
[0]
[1]
[2]
[3]
[4]
[5]
[6]
[7]
30
31
32
33
34
35
36
37
[8]
[9]
[M1]
[M2]
[M3]
[M4]
[M5]
[M6]
38
39
40
41
42
43
44
45
Head set mode is selected by connecting pin "HEAD"
to VDD and enabling the head function by service code
programming (see also Table 3: Parameter settings).
Rev. 1.3
Page 12
May 1999
Preliminary
AS2525
Table 21: Headset Rx gain setting
[PG] + [0] + (Password) + [0] + [8] + (x) + [PG]
Key
(x)
Rx Gain (dB)
LS to RO
Key
(x)
Rx Gain (dB)
LS to RO
[0]
[1]
[2]
[3]
[4]
[5]
[6]
[7]
-6
-5
-4
-3
-2
-1
0
1
[8]
[9]
[M1]
[M2]
[M3]
[M4]
[M5]
[M6]
2
3
4
5
6
7
8
9
Ring Frequency Detection
The ring frequency detector assures that only signals
with a frequency between 13 Hz and 70 Hz are
regarded as valid ring signals.
When a valid ring signal is present for 100 ms
continuously, the melody generator is activated and
remains active as long as the ring signal is present.
If this mode is entered both hook inputs HS and HF
act as electronic off-hook for handset operation. The
gain in transmit and receive can be programmed by
service code programming. The pin "HEAD" is only
scanned once after off-hook and any change on this
pin during one session will be ignored.
Rev. 1.3
Once the melody generator has been started, the
ring signal is continuously monitored and the melody
generator is instantly turned on or off according to
the momentary presence of a valid or invalid ring
signal respectively (until next POR or off-hook).
DC/DC converter
When a valid ring signal is detected, the dc/dc
converter is started.
Page 13
May 1999
Preliminary
AS2525
5. Press [PG] (= store and exit) or go onhook to abort.
Dialling and Control Functions
Valid Keys
The key scanning is enabled in off-hook mode with
VDD above VREF. A valid key is detected from the
keyboard by connecting the appropriate row to the
column (RON < 1 kΩ). This can be done using an n x
m keyboard matrix with single contacts. Three diodes
and a resistor are used to extend the number of rows
(see Figure 4: Keyboard Layout).
Key Lock
A key lock function is provided to allow the user to
protect the telephone from any mis-use. When this
function is available through the set-up programming,
it is possible to enable/disable the key lock using the
user PIN code.
Enabling/disabling key lock:
PIN Code
1. Press [PG] to enter programme mode
A PIN code is available for protection various user
settings. The default PIN code is set to 1111 and can
be change as follows:
2. Press [1] +(PIN) + [#] + [6]
3. Press [1] for enable or [0] for disable
1. Press [PG] to enter programme mode
4. Press [PG] (= store and exit) or go onhook to abort
2. Press [1] + (PIN) + [0]
3. Key in new PIN code (valid digits: 0 - 9, #)
4. Key in new PIN code again
5. Press [PG] (= store and exit) or go onhook to abort
It is also possible to reset the PIN code through setup programming:
Also an easy key lock function is provided. This
function can be activated/disactivated when the key
lock function is available through set-up programming
and the previous mentioned key lock through PIN
code is disabled.
Clear Memory Procedure
It is possible to clear all stored numbers by using the
PIN code as follows:
1. Press [PG] to enter programme mode
1. Press [PG] to enter programme mode
2. Press [0) + (Password) + [#] + [0]
2. Press [1) + (PIN) + [#] + [7]
3. Press [1] to reset
3. Press [1] for clear
4. Press [PG] (= store and exit) or go onhook to abort
Call Restriction
A call restriction function is accommodated. This
function can be activated using the PIN code.
4. Press [PG] (= store and exit) or go onhook to abort
Reset to Factory Settings
It is possible to reset all settings to the default factory
settings with following procedure:
Storing digits for call restriction:
1. Press [PG] to enter programme mode
1. Press [PG] to enter programme mode
2. Press [1] + (PIN) + [#] + [8]
2. Press [1] + (PIN) + [∗]
3. Press [1] for reset
3. Press [1] for first call restriction and [2]
for second call restriction
4. Press [PG] (= store and exit) or go onhook to abort
4. Key in digits for call restriction (2 digits,
[MT] for blank)
Rev. 1.3
Page 14
May 1999
Preliminary
AS2525
Table 22: Flash duration setting
Dial Mode Selection
The default signalling mode (LD or MF) is selectable
through following procedure:
[PG] + [0] + (Password) + [∗] + (digit) + (HEX) + [PG]
Digit
1. Press [PG] to enter programme mode
2. Press [3] to enter dial select mode
Timing
Flash Duration
[4]
HEX code
Flash 1
[5]
HEX code
Flash 2
One of two pre-programmed can be selected as
follows:
3. Press [0] for LD and [1] for MF
4. Press [PG] (= store and exit) or go onhook to abort
1. Press [PG] to enter programme mode
2. Press [2] to enter flash select mode
When default LD mode is selected, a temporary
change to MF can be invoked by pressing the [∗]
key. Temporary MF select with tone on first key
pressure can be selected as option (see also Table
3: Parameter settings). The circuit will revert to LD by
pressing the [FL] key or by next on-hook.
Re-Dialling (Last Number Redial)
Re-dialling is a facility that allows re-signalling of the
last dialled number without keying in all the digits
again. Numbers dialled out from any memory will
also be stored in the LNR memory. The re-dialling
works in following manner:
• Any digit (including Flash, Pause, and MF select)
being dialled is storable in the LNR memory up to
a total of 31 digits.
• If more than 31 digits are entered, re-dialling will
be inhibited.
• Pressing the [R/P] key as first entry after off-hook
(LNR cursor at first digit) will invoke dialling the
content of the LNR memory.
• If the [R/P] key is pressed after entering one or
more digits, the key will function as a pause key
and each pressure will insert a pause.
Pauses can also be inserted by pressing the [R/P]
key in programme mode.
3. Press [0] for duration 1 and [1] for
duration 2
4. Press [PG] (= store and exit) or go onhook to abort
A flash entered will be stored in the LNR memory
together with entered digits. After a recall a 270 ms
pause will automatically be executed.
Pauses
Pauses can be inserted if the [R/P] key is pressed
after entering one or more digits. Also during
programming, pauses can be inserted by pressing
the [R/P] key. Default pause duration is 1 second
(P1) and an alternative pause of 3 second (P2) can
be selected. These pauses can be changed through
the set-up programming (see Table 3: Parameter
settings)
Memory Keys
The keys [M1] to [M8] are direct memory access
keys, [SH] key is used to access second level of
direct memories, and the [MR) key is used for keycode dialling. Up to 26 numbers can be stored in the
on-chip RAM. Each number can contain up to 21
digits (including pauses).
During programming multiple pauses can be inserted
by pressing the [RD] key.
Flash Function
A flash, [FL] key, activation will invoke a timed loop
break. The flash duration can be programmed
through set-up (see Figure 5: Keys for HEX-code
entry and Table 4: Timing selection by HEX code):
Example (45678P123 is stored in M1, where P is a
pause and 123 the extension number):
1. Off-hook, wait for dial tone
2. Press [M1]
• 45678 is dialled out
• Dialling halts (pauses)
• Dialling is resumed, 123 is dialled out.
Rev. 1.3
Page 15
May 1999
Preliminary
AS2525
Memory dialling is cascadable up to a the maximum
of 31 digits/data.
Table 25: Basic ringer melody selection
[PG] + [0] + (Password) + [#] + [8] + (digit) + [PG]
Tone Generator
Digit
The tone generator incorporates the DTMF tones, 3
frequencies for the tone ringer and pacifier tones.
DTMF
Ringer Melody
[0]
2-tone
[1]
3-tone
The DTMF generator provides 7 frequencies.
The user can chose the following melodies as shown
in below table.
Table 23: DTMF frequencies
Table 26: 3-tone melody programming
Digit
Rows
1-2-3
4-5-6
7-8-9
*-0-#
Columns
1-4-7-*
2-5-8-0
3-6-9-#
Frequency
Low Group
697 Hz
770 Hz
852 Hz
941 Hz
High Group
1209 Hz
1336 Hz
1477 Hz
Procedure
Digit
[PG] + [7] +
Sequence
Rate
[0]
F1 F2 F3 F1 F2 F3
1
[1]
F1 F2 F3 F1 F2 F3
2
[2]
F1 F2 F3 F1 F2 F3
4
[3)
F1 F2 F3 F1 F2 F3
6
[4]
F1 F2 F3 F1 F2 F3
10
Press [PG] to store and terminate
The MF output level can be set through set-up
programming. The range is from -18 dBm to -6 dBm
in 1 dB steps.
Table 24: DTMF level settings
When 2-tone melody is selected through the set-up
procedure, it is possible to chose the following
melodies:
[PG] + [0] + (Password) + [0] + [7] + (x) + [PG]
Key
(x)
Level (dBm)
Low Group
Key
(x)
Level (dBm)
Low Group
[0]
[1]
[2]
[3]
[4]
[5]
[6]
-18
-17
-16
-15
-14
-13
-12
[7]
[8]
[9]
[M1]
[M2]
[M3]
-11
-10
-9
-8
-7
-6
The chosen melody will be heard in the loudspeaker
during programming. Pressing the [PG] key will end
the procedure and the last selected melody will be
stored.
Table 27: 2-tone melody programming
Procedure
Digit
[PG] + [7] +
The pre-emphasis is 2.6 dB. The DTMF tones are
according to CEPT recommendations.
Tone Ringer (Melody/Volume)
Sequence
Rate
[0]
F1 F2 F1 F2 F1 F2
2
[1]
F1 F2 F1 F2 F1 F2
5
[2]
F1 F3 F1 F3 F1 F3
2
[3)
F1 F3 F1 F3 F1 F3
5
[4]
F2 F3 F2 F3 F2 F3
2
Press [PG] to store and terminate
The tone ringer incorporates two basic selection,
namely 2-tone or 3-tone melodies. The default set-up
selection is the 3-tone ringer.
Repetition rate means that a sequence of 6
frequencies is repeated 1, 2, 4, 5, 6 or 10 times
within 1 second.
Pacifier Tone
Any key entry is acknowledged by a pacifier tone
(key-in tone) of 1333 Hz. The pacifier tone can be
enabled/disabled through set-up programming.
Rev. 1.3
Page 16
May 1999
Preliminary
AS2525
Table 28: Pacifier tone selection
Serial Bus
The AS2525 incorporates a serial bus (DO, DI, and
CLK) with two chip select outputs (CS1 and CS2).
The serial bus is used to:
[PG] + [0] + (Password) + [#] + [9] + (digit) + [PG]
Digit
Pacifier Tone (Key-in Tone)
[0]
Disabled
[1]
Enabled
• sending data to the LCD driver (AS2591) when a
key is pressed or a number is dialled out
• reading and writing to the external EEPROM
under following conditions:
Table 29: Pacifier tones
Table 31: EEPROM read/write timings
Key Entry
Frequency
Duration
Acknowledge
1333 Hz
40 ms
Reject/Terminate
1333 Hz
4 x 40 ms
ACTION
An invalid key entry will be indicated by a rejection
tone of 4 times 40 ms.
By MF dialling the DTMF tones are provided to the
earpiece as comfort tone. The level of the comfort is
selected through the set-up programming.
DURATION
After off-hook (debounced)
50 ms
After on-hook (debounced)
200 ms
After first rising edge at FCI
10 ms
After PG is terminated
12…600 ms
After pressing [V+]/[V-]
20 ms
See also AS2591 data sheet for further information.
Table 30: DTMF comfort tone level setting
[PG] + [0] + (Password) + [0] + (y + x) + [PG]
Key
(y + x)
Level (dBr)
Earpiece
Key
(y + x)
Level (dBr)
Loudspeaker
[9] + [0]
[9] + [1]
[9] + [2]
[9] + [3]
-36
-30
-24
-18
[0] + [0]
[0] + [1]
[0] + [2]
[0] + [3]
-15
-9
-3
3
Rev. 1.3
LCD Control
The AS2525 is designed to work together with the
LCD driver AS2591 (see also AS2591 data sheet).
Page 17
May 1999
Preliminary
AS2525
Electrical Characteristics
Absolute Maximum Ratings*
Supply Voltage............................................................................................................................... -0.3 ≤ VDD ≤ 7V
Input Current..........................................................................................................................................+/- 25 mA
Input Voltage (LS) ....................................................................................................................... -0.3V ≤ VIN ≤ 12V
Input Voltage (LI, CS)................................................................................................................... -0.3V ≤ VIN ≤ 8V
Input Voltage (STB, RI) .........................................................................................................-2V ≤ VIN ≤ VDD +0.3V
Digital Input Voltage ..........................................................................................................-0.3V ≤ VIN ≤ VDD + 0.3V
Electrostatic Discharge...........................................................................................................................+/- 1000V
Storage Temperature Range........................................................................................................... -65 to +125°C
Total Power Dissipation ............................................................................................................................ 500mW
*Exceeding these figures may cause permanent damage. Functional operation under these conditions is not permitted.
Recommended Operating Range
Symbol
Parameter
Conditions
Min.
Typ.*
VDD
Supply Voltage (internally generated) Speech mode
3.0
5.0
V
TAMB
Ambient Operating Temp. Range
-25
+70
°C
fOSC
Oscillator Frequency
Resonator: Murata CSA
3.58M G312AM
Max.
3.58
Units
MHz
* Typical figures are at 25°C and are for design aid only; not guaranteed and not subject to production testing.
DC Characteristics
(ILINE = 15 mA, recommended operating conditions unless otherwise specified)
Symbol
Parameter
Conditions
IDD
Operating Supply Current
Min.
Typ.
Max.
Speech mode
4
6
mA
Handsfree mode
11
13
mA
LD dialling, VDD = 2.5V
200
µA
Ring mode, VDD = 2.5V
300
µA
IDD-EXT
Available Supply Current
for Peripheral Circuits
Speech mode or MF dialling
IDD0
Idle Current
Idle mode, VDD = 2 V, TAMB = 25°C
V
Line Voltage, LIVolt = 0
13 mA< ILINE < 100 mA
LI
Line Voltage, LIVolt = 1
2
mA
2
µA
3.2
3.5
3.8
V
4.2
4.5
4.8
V
IOL
Output Current, Sink
Pin CS, SS
VOL = 0.4V
VIL
Input Low Voltage
TAMB = 25°C
VSS
VIH
Input High Voltage
TAMB = 25°C
0.7 VDD
Rev. 1.3
1
Page 18
Units
mA
0.3 VDD V
VDD
V
May 1999
Preliminary
AS2525
AC Electrical Characteristics
ILINE = 15 mA; f = 800 Hz; ZAC = 1000Ω ; recommended operating conditions and default settings unless otherwise
specified.
Transmit
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Units
ATX
Transmit Gain, default
M1/M2 to LS
34.3
35.8
37.3
dB
M3/M4 to LS
42.0
44.0
46.0
dB
Variation with Frequency
f = 500 Hz to 3.4 kHz
THD
Distortion
VLS < 0.25 VRMS
VAGC
Soft Clip Level
VLS =
ASCO
+/- 0.8
dB
2
%
2
V
Soft Clip Overdrive
20
dB
tDECAY
Attack Time
70
µs/6dB
tDECAY
Decay Time
100
ms/6dB
ZIN
Input Impedance; M1/M2
10
kΩ
Input Impedance; M3/M4
10
kΩ
AMUTE
Mute Attenuation
Mute activated
VNO
Noise Output Voltage
TAMB = 25°C, handset mode
ATX = 37 dB
VIN MAX
Input Voltage Range;
M1/M2 and M3/M4
Differential
60
dB
-72
+/- 1
dBmp
VPEAK
Line Driver
Symbol
Parameter
VIN MAX
Input Voltage Range; LI
+/- 2
VPEAK
VTX
Dynamic Range; LI
+/- 2
VPEAK
RL
Return Loss
∆ZAC/TEMP
Temperature Variation
Rev. 1.3
Test Conditions
ZRL = 1000 Ω; TAMB = 25°C
Min.
Typ.
18
Units
dB
0.5
Page 19
Max.
Ω/°C
May 1999
Preliminary
AS2525
Receive
Symbol
Parameter
Condition
Min.
Typ.
Max.
Units
ARX
Receive Gain, Default
LS to RO; volume reset
-2.0
-0.5
1.0
dB
LS to LO1/LO2; volume max.
25.0
27.0
29.0
dB
ARX-VOL
Volume Control Range
8 steps through [V-]/[V+] keys
∆ARX
Variation with Frequency
f = 500 Hz to 3.4 kHz
THD
Distortion, RO
VRO = 0.25 VRMS
2
%
Distortion, LO1/LO2
VLO1/2 = 0.25 VRMS
5
%
VAGC
Soft Clip Level
VRO =
ASCO
Soft Clip Overdrive
tDECAY
Attack Time
tDECAY
Decay Time
VNO
Noise Output Voltage, RO
TAMB = 25°C, ARX = 3 dB
-72
dBmp
VUFC
Unwanted Frequency
Components
50 Hz.........20 kHz
-60
dBmp
ZIN
Input Impedance, RI
VIN-MAX RI
Input Voltage Range, RI
AST
Side Tone Cancellation
ZIN
Input Impedance, STB
VIN-MAX ST
Input Voltage Range, STB
VRI > 0.8 VRMS
15
dB
+/- 0.8
dB
1
VPEAK
10
dB
70
µs/6dB
100
ms/6dB
kΩ
8
+/- 2
VRI < 0.25 VRMS
VPEAK
26
dB
kΩ
80
+/- 2
VPEAK
General Timings
Symbol
Parameter
td
Key Debounce Time
tHS-L
Low/High Debounce
tHS-H
tFD
Condition
Min.
Max.
Units
15
ms
HS Input (going off-hook)
15
ms
High/Low Debounce
HS Input (going on-hook)
210
ms
Flash Duration
FL 1 (default)
100
FL 2 (default)
275
tPFP
Post Flash Pause
tAP
Access Pause
285
102
ms
300
ms
274
P1 (default)
P2 (default)
Rev. 1.3
Typ.
Page 20
0.9
1.0
3.0
ms
1.1
sec.
sec.
May 1999
Preliminary
AS2525
DTMF
Symbol
Parameter
Condition
Min.
DF
Frequency Deviation
Deviation of ceramic resonator is
not included
VMF
MF Tone Level at LS
(Low Group)
Default
VMF-RANGE
MF Tone Level Range at
LS (Low Group)
13 steps
∆VL_H
Pre-emphasis, Low to
High
VUFC
Unwanted Frequency
Components
300 Hz....4.3 kHz
4.3 kHz…7 kHz
7 kHz....10 kHz
10 kHz…14 kHz
14 kHz....28.5 kHz
28.5 kHz....40 kHz
tTD
Tone Duration, Minimum
Default
80
82.3
85
ms
tITP
Inter Tone Pause, Min.
Default
80
82.3
85
ms
tTR
Tone Rise Time
From 10% to 90% amplitude
5
ms
tTR
Tone Fall Time
From 90% to 10% amplitude
5
ms
VCT
Comfort Tone Level, RO
Relative to LS, 4 steps
Symbol
Parameter
Condition
Min.
Typ.
Max.
Units
tDR
Dialling Rate
Default
9.53
10
10.5
pps
-4.5
Typ.
-5.5
Max.
1.2
%
-6.5
dBm
-18/-6
2.0
2.6
Units
dBm
3.2
dBr
- 40
-46
- 52
-58
- 70
- 80
dBm
dBm
dBm
dBm
dBm
dBm
- 36
-18
dBr
LD Dialling
Option
t/B
tM/
Break Period
Make Period
tPDP
Pre-Digit Pause
tIDP
Inter-Digit Pause
Rev. 1.3
20
Default
57
61.2
pps
63
ms
Option
66
ms
Option
33
ms
Default
38
40.8
42
ms
Option
33
ms
Option
16.5
ms
35
ms
800
Page 21
880
ms
May 1999
Preliminary
AS2525
Tone Ringer
Symbol
Parameter
F1
Condition
Min.
Typ.
Max.
Units
Frequency 1
770
800
830
Hz
F2
Frequency 2
1025
1067
1110
Hz
F3
Frequency 3
1280
1333
1385
Hz
tDT
Detection Time
fMIN
Min. Detection Frequency
12
13
14
Hz
fMAX
Max. Detection Frequency
68
70
75
Hz
Min.
Typ.
Max.
Initial
100
ms
Pacifier Tone
Symbol
Parameter
Condition
VPARO
Tone Output Level, RO
RL = 150 Ω
30
mVP-P
Tone Output Level, LO1/2
RL = 32 Ω
300
mVP-P
fPT
Frequency
Key entry
1333
Hz
tTBD
Tone Burst Duration
Key entry
40
ms
Acknowledge, terminate PG
mode
140
ms
Rejection, invalid key entry
4x40
ms
80
ms
tITP
Rev. 1.3
Inter-Tone Pause
Page 22
Units
May 1999
Preliminary
AS2525
Timing Diagrams
LD dialling
MUTE
MASK
DPN
tIDP
tPDP
tB
tM
tB
tM
tB
tM
tB
tM
tIDP
tPDP
tB
tM
LD dialling with access pause
MUTE
MASK
DPN
tIDP
tPDP
tAP
tIDP
Pause
tPDP
tB
tM
MF dialling
MUTE
MASK
DPN
TONE
tTD
tITP
tTD
tAP
tITP
tTD
Pause
tITP
Flash
MUTE
MASK
DPN
tM
tFD
Flash1/2
tM
tPFP
tM
tFD
Flash1/2
tM
Figure 12: Timing diagrams
Rev. 1.3
Page 23
May 1999
Preliminary
AS2525
Test Circuit
25
CM
A
CI
18
15 n
17
LS
M1
1k
10
10 µ
100 µ
15
30 ohm
15 n
8
RI
M2
ILINE
600 ohm
11
300 ohm
UL
6k
STB
M3
15 n
9
1k
1µ
10 V
15 n
7
M4
B
14
LI
AGND
23
10 µ
12
BC
327
CS
13
Vss
OSC
33
26
SS
VPP
22 µ
29
VsSA
44
AS2525
3.58 MHz
16
BC
327
CS1
43
42
27
LO1
32 ohm
LO2
28
10 µ
RO
100 n
19
RECI
DO
DI
150 ohm
21
RECV
100 n
10 k
10 µ
10 k
20
41
CLK
1
CS2
FT1
5
2
DPn
3
FT2
6
10 µ
24
10 µ
HF
4
32
HS
CBN
LED
30
22
DM/HM
VDD
31
22 µ
FCI
37
C1
34
38
39
40
C2
R1
C3
R2
C4
R3
35
36
Figure 13: Test circuit
Rev. 1.3
Page 24
May 1999
Preliminary
AS2525
Typical Application
Figure 14: Typical application
Rev. 1.3
Page 25
May 1999
Preliminary
AS2525
Package Outline
44 Pin TQFP
See Package Catalogue
Devices sold by Austria Mikro Systeme Int. AG are covered by the warranty and patent indemnification provisions appearing in
its Term of Sale. Austria Mikro Systeme Int. AG makes no warranty, express, statutory, implied, or by description regarding
the information set forth herein or regarding the freedom of the described devices from patent infringement Austria Mikro
Systeme Int. AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to
designing this product into a system, it is necessary to check with Austria Mikro Systeme Int. AG for current information. This
product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual
environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment
are specifically not recommended without additional processing by Austria Mikro Systeme Int. AG for each application.
Copyright © 1999, Austria Mikro Systeme International AG, Schloss Premstätten, 8141 Unterpremstätten, Austria.
Trademarks Registered®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated,
stored, or used without the prior written consent of the copyright owner.
Austria Mikro Systeme Int. AG reserves the right to change or discontinue this product without notice.
Rev. 1.3
Page 26
May 1999