Datasheet

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austriamicrosystems
austriamicrosystems
Data Sheet AS2540
Remote Controlled Single-Chip-Telephone
AS2540
DATA SHEET (PRELIMINARY)
General Description
Key Features
The AS2540 is a CMOS integrated circuit that
incorporates a speech circuit (line-adaptation, 2/4-wire
conversion, separate Rx- and Tx-amplifiers for handset
and modem), MF dialler, ring frequency detector, ring
melody generator and a two wire serial interface. It
shall act as an a/b-line-powered device in order to
interface a main-powered CPU to the analogue
telephone line.
-
-
AS2540 can operate in a so-called mainpower mode
and in a backup mode. During mainpower mode, a
watchdog timer is running on AS2540, which has to be
reset via the serial interface, which is connected to the
CPU through opto-couplers. During backup mode (=
The main-power failure or SW engine problem),
AS2540 can operate as an independent basic MF
dialler (digits 0-9*#)
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Block Diagram
Line
ca
Main Power Mode
Backup Mode
Line
LS
LI
+ 6dB
ROH
-2d B
+ 2d B
ROT
ni
RI
STB
LS
LI
+ 6dB
M1
M2
CS
M1
M2
TIT
TIT
CI
DPn
AGND
DPn
AGND
DTMFg enerator
SDPn
SROT
SROH
STIT
SMUTE
Dia l
Dig it
SMASK
DTMFgenerator
SDPn
ch
ROT
Mask
CI
Te
+ 2d B
CS
Mask
RxD
RxD
DIALLER
UART
DIALLER
TxD
TxD
R1
R2
R1
R2
MODE
VDD
VDD
RFD
RFD
MO
VSS
MO
EHS
OSC
EHS
MHS
UART
C1
C2
C3
C1
C2
C3
MODE
Revision 3.1
ROH
-2dB
RI
STB
SROT
-
-
SROH
-
28 pin SOIC
Dice-on-Foil
STIT
-
-
SMUTE
-
Package
Web Telephones
Answering Machines
Fax Machines
Base Station of Cordless Telephones
Hospital Communication Units
Dial
Digit
-
SMASK
Applications
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Line Interface, Speech Circuit, MF Dialler and Tone Ringer
on a 28 pin CMOS chip
Programmable via 2-wire serial interface
(UART 9600 baud, 8N1)
Watch dog timer for Backup Mode
Additional input for modem transmit path
Additional output for modem receive path
CMOS for high EMC immunity
Low Noise (max. –72 dBm)
Operating range from 15mA to 100mA (down to 5mA with
reduced performance)
Soft clipping for handset operation to avoid harsh distortion
Line loss compensation selectable by pin option
Real and complex impedance selectable by external
components
Side tone adaption selectable by external components
Ring frequency discrimination
3-tone ring melody generator
VSS
OSC
MHS
Page 1 of 18
austriamicrosystems
Data Sheet AS2540
Pin Description
Pin #
Symbol
15
RFD
Function
R ing F requency D iscrimination
Schmitt trigger input for ring frequency discrimination. Disabled during off-hook.
7
LS
L ine Current S ense Input
5
LI
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Input for sensing the line current
L ine I nput
Input used for power extraction and line current sensing
RI
R eceive I nput
Input for ac-separated receive signal
2
STB
S ide T one B alance Input
3
CS
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Input for side tone cancellation network
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6
C urrent S hunt 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
8
CI
C omplex I mpedance Input
Input pin for the capacitor to program a complex impedance
16
DPn
D ial P ulse Output
Open drain output pulls low during break periods of pulse dialling and flash
17
EHS
E lectronic H ook S witch
Schmitt Trigger Input to detect an electronic off-hook.
18
MHS
M anual H ook S witch
Schmitt Trigger Input to detect a manual off-hook.
MODE
D TMF L evel S election
ca
19
ni
-4/-6dBm
-6/-8dBm
-8/-10dBm
—>
—>
—>
DLS open
DLS-r1
DLS-r2
L ine L oss C ompensation Select Pin
ch
45mA-75mA
20mA-50mA
None
MO
Te
28
11
4
VDD
VSS
Ring
—>
—>
—>
LLC open
LLC-r3
LLC-r4
M elody O utput
PDM output of the ring melody generator.
V oltage D rain D rain
Positive Power Supply
V oltage S ource S ource
Negative Power Supply
Revision 3.1
Page 2 of 18
austriamicrosystems
Data Sheet AS2540
Pin #
Symbol
25
OSC
Function
O scillator Input
Input for ceramic resonator 3.58MHz.
Recommended type: Murata CSA 3.58MG312AM or compatible
12
AGND
A nalogue G round
Special ground for the internal amplifiers
RXD
R eceive D ata Input
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26
Schmitt trigger input to serial interface
27
TXD
T ransmit D ata Output
R1
R2
Keyboard
R ows
22
23
24
C1
C2
C3
Keyboard
C olumns
10
ROT
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21
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Open drain output from serial interface
R eceive O utput to T ransformer
Output for driving a transformer with an ac impedance larger than 10kΩ
1
TIT
T ransformer I nput from T ransformer
Single ended input for transformer
9
ROH
R eceive O utput to H andset
Output for driving a dynamic earpiece with an impedance from 150Ω to 300Ω
M2
M1
M icrophone Inputs
Differential inputs for the microphone (electret)
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13
14
Revision 3.1
Page 3 of 18
austriamicrosystems
Data Sheet AS2540
Example Main Power Mode
Functional Description
Line
Modes of operation
LS
LI
+ 6dB
There are 4 possible modes:
RI
STB
Idle Mode
CS
+ 2dB
ROT
M1
M2
Mask
SROH
STIT
SMUTE
Dial
Digit
lv
RxD
DIALLER
AS2540 is supplied via the ring capacitor and external
path, manual hook -switch and electronic hook-switch is
C1
C2
C3
R1
R2
MODE
UART
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open (MHS ∩ EHS = logical 0), the oscillator is running, a
valid incoming ringing is signalled via the serial interface to
the CPU. If the CPU does not reply the AS2540 switches
into backup mode and sends a ring melody to the MO
output.
TxD
VDD
RFD
MO
EHS
VSS
OSC
MHS
Start-up in backup mode
Backup Mode
Manual hook-switch and/or electronic hook-switch is closed
(MHS ∪ EHS = logical 1), AS2540 is supplied with line
current, the oscillator is running, the keyscan is enabled
and the handset path is switched on, signalling via the
serial interface is possible. After AS2540 has started
dialling in backup mode, he must not be interrupted any
more in order to ensure consistent dialling. A mode
transition BM -> MPM is only possible before AS2540 has
started dialling digits independently.
ca
Main Power Mode
Manual hook-switch and/or electronic hook-switch is
ch
ni
closed, AS2540 is supplied with line current (MHS ∪ EHS
= logical 1), the oscillator is running, the keyscan is
disabled, AS2540 is controlled via the serial interface,
handset path or monitor path or modem path is on,
signalling via the serial interface is possible.
Select Operation Mode
Command Message
<SetHandsetPath>
<SetModemPath>
<SetMonitorPath>
Te
SROT
AGND
DTMFgenerator
Ringing Mode
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DPn
SDPn
is open (MHS ∩ EHS = logical 0), no ring signal is applied,
the oscillator is stopped, signalling via the serial interface
is not possible.
TIT
CI
SMASK
Manual hook-switch and electronic hook-switch (e.g. relay)
Revision 3.1
ROH
-2dB
Switches ON
SROH
SROT & STIT
SROH & SROT
Switches OFF
SROT & STIT
STIT
As soon as AS2540 is supplied with line current, the
external V dd capacitor will be charged up via the LI and
VDD pin and after the V dd voltage has reached the
operating level, the handset path of the speech circuit is
switched on. This off-hook status is also signalled to the
internal logic via the MHS or EHS pin in order to start the
pinscan and subsequently set the country specific modes.
Additionally a <LineEvent> message is sent to the CPU.
Start-up in ring mode
When a ringing signal is applied to the line, V dd of AS2540
is charged up via an external path. After V dd has reached
the operating voltage the oscillator starts and AS2540
discriminates the ring frequency. After a valid ring
frequency is applied on the RFD pin, the logic sends a
<LineEvent> message is sent to the CPU and a watchdog
timer is started. When the <LineEvent> message is not quit
by the CPU before the watchdog timer has finished the
countdown, AS2540 changes into backup mode and sends
out a melody via the MO pin.
DC conditions
The normal operating mode is from 15mA to 100mA. An
operating mode with reduced performance is from 5mA to
15mA. In the line hold range from 0mA to 5mA the device
is in a power down mode and the voltage at LI is reduced
to a maximum of 3.5V
Page 4 of 18
austriamicrosystems
Data Sheet AS2540
pin and a 30Ω resistor between LI and LS pin. It can be
calculated by the following equation: V LS = V LI + I Line *
30Ω. The t.m. voltage at the LI pin is 4.5V. The calculation
leads to the following DC resistances: 330Ω to 75Ω at line
currents from 15mA to 100mA.
2/4 wire conversion
AS2540 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.
Receive path
The gain of the LS —> ROH receive path is set to 2dB for
ac-impedance 1000Ω. The receive input is the differential
signal of RI and STB. During DTMF dialling a MF comfort
tone is applied to ROH which is -30dB relative to the line
level. The soft clip circuit limits the output voltage at ROH
to 1V p. It prevents harsh distortion and acoustic shock.
The gain of the LS —> ROT receive path is set to 0dB for
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The DC characteristic is determined by the voltage at LI
ac-impedance 1000Ω. The receive input is the differential
signal of RI and STB. The soft clip circuit is not active for
this output.
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Modescan
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The DTMF-level on the line and the function of the line loss
compensation can be selected with the connection of the
MODE-pin to the keyboard matrix. The MODE-pin is
scanned once after each OFF-Hook transition.
PIN
MODE
A1=3.4/3.5
A2=-0.4
R1
R2
AC impedance
The ac impedance of AS2540 is set to t.m. 1000Ω. With
the external capacitor at CI pin it can be programmed
complex. With a parallel impedance at the LS pin it can be
programmed to 600Ω.
Side Tone
Z BAL /Z LIN E = 10
C3
C1
ch
The gain of the TIT —> LS transmit path is set to 8dB for
ac-impedance 1000Ω. The input is single ended with an
impedance of 25kΩ. The soft clip circuit is not active for
this input. The dynamic range of this path is 2.5Vp at LS.
1
4
7
*
2
5
8
0
3
6
9
#
R2
X
X
X
X
X
PIN
R2
C3
45mA-75mA
-6dBm
45mA-75mA
-8dBm
45mA-75mA
-10dBm
20mA-50mA
-6dBm
20mA-50mA
-8dBm
X
20mA-50mA
-10dBm
X
No LLC
-6dBm
No LLC
-8dBm
No LLC
-10dBm
X
X
C2
PIN
R1
Dtmf Level
X
for ac-impedance 1000Ω. The input is differential with an
impedance of 25kΩ. The soft clip circuit limits the output
voltage at LS to 2V p. The attack time is 30µs/6dB and the
decay time is 20ms/6dB.
PIN
C3
LLC
X
The gain of the M1/M2 —> LS transmit path is set to 38dB
Te
C2
X
ni
Transmit path
PIN
C2
c1
ca
A good sidetone cancellation can be achieved by using the
following equation:
PIN
C1
X
R1
X
X indicates connection to pin mode
Revision 3.1
Page 5 of 18
austriamicrosystems
Data Sheet AS2540
Serial interface
communication principle is derived from a standard UART:
Baud Rate
9600
Start Bit
1
Data Bits
8
Parity
None
Stop Bit
1
LSB is transferred prior to MSB
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The
-
Rx - messages
Message Format
X
d5
d4
d3
d2
d1
1
LSB
d7
d6
d5
d4
d3
d2
d1
d0
DTMF-dial message
x
x
0
1
0
1
0
1
Digit 0
Starts DTMF dialling of digit
x
x
0
0
0
0
1
1
Digit 1
Starts DTMF dialling of digit
x
x
0
0
0
1
0
1
Digit 2
Starts DTMF dialling of digit
x
x
0
0
0
1
1
1
Digit 3
Starts DTMF dialling of digit
x
x
0
0
1
0
0
1
Digit 4
Starts DTMF dialling of digit
x
x
0
0
1
0
1
1
Digit 5
Starts DTMF dialling of digit
x
x
0
0
1
1
0
1
Digit 6
Starts DTMF dialling of digit
x
x
0
0
1
1
1
1
Digit 7
Starts DTMF dialling of digit
x
x
0
1
0
0
0
1
Digit 8
Starts DTMF dialling of digit
x
x
0
1
0
0
1
1
Digit 9
Starts DTMF dialling of digit
x
x
0
1
0
1
1
1
Digit *
Starts DTMF dialling of digit
x
x
0
x
x
0
x
x
0
x
x
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Notes
0
0
0
1
Digit #
Starts DTMF dialling of digit
1
1
0
0
1
Digit A
Starts DTMF dialling of digit
1
1
0
1
1
Digit B
Starts DTMF dialling of digit
1
1
1
0
1
Digit C
Starts DTMF dialling of digit
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0
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X
MSB
x
0
1
1
1
1
1
Digit D
Starts DTMF dialling of digit
x
x
1
0
0
0
0
1
KeyReleased
Stops Dialling
Te
x
d7
d6
d5
d4
d3
d2
d1
d0
Pin-Control message
x
x
1
0
1
1
0
1
SetDPn_HIGH
Release pin Dpn (open drain)
x
x
1
0
0
0
1
1
SetDPn_LOW
Force pin DPn = VSS
x
x
1
0
0
1
0
1
SetMask
Force LI-Voltage to 1.2 V
x
x
1
0
0
1
1
1
ResetMask
Revision 3.1
Notes
Page 6 of 18
austriamicrosystems
Data Sheet AS2540
d7
d6
d5
d4
d3
d2
d1
d0
Pin-Control message
x
x
1
0
1
1
1
1
SetTestmode
FOR FACTORY TEST ONLY
x
x
1
0
1
0
0
1
MuteON
Mute Transmit path
x
x
1
0
1
0
1
1
MuteOFF
d7
d6
d5
d4
d3
d2
d1
d0
Path-Control message
x
x
1
1
0
0
1
1
SetHandsetPath
x
x
1
1
1
0
1
1
SetMonitorPath
x
x
1
1
0
1
0
1
SetModemPath
x
x
1
1
0
0
0
1
RequestStatus
AS2540 sends Status information
x
x
1
1
0
1
1
1
reserved
<LineEvent>
x
x
1
1
1
0
0
1
reserved
<LineEvent>
x
x
1
x
x
1
<Ack> message
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Tx messages
Notes
1
1
1
0
1
reserved
<LineEvent>
1
1
1
1
1
reserved
<LineEvent>
<Ack> message format for <RequestStatus>
b6
b5
b7
b6
b5
1
0
1
0
b3
b2
0
1
LSB
b4
b3
b2
b1
b0
Status
0
1
valid ring signal detected
0
1
no ring signal
0
1
manual hook switch - off-hook (pin MHS)
0
1
manual hook switch - on-hook (pin MHS)
0
1
electronic hook switch - off-hook (pin EHS)
0
1
electronic hook switch - on-hook (pin EHS)
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b4
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b7
MSB
0
0
0
0
1
no LLC comparator .....................
0
0
1
0
1
LLC comparator 20mA (45mA) ...
0
1
0
0
1
LLC comparator 26mA (51mA) ...
0
1
1
0
1
LLC comparator 32mA (57mA) ...
1
0
0
0
1
LLC comparator 38mA (63mA) ...
1
0
1
0
1
LLC comparator 44mA (69mA) ...
1
1
0
0
1
LLC comparator 50mA (75mA) ...
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0
Revision 3.1
Remark
Status of AS2540
coded status of
LLC comparator
Page 7 of 18
austriamicrosystems
Data Sheet AS2540
<Line Event> Message
<LineEvent> message format
b7
MSB
b6
b5
1
1
1
1
1
LSB
b7
b6
b5
b4
b3
b2
b1
b0
Status
1
1
1
1
10
1
valid ring signal detected
0
1
1
1
10
1
no ring signal
1
1
1
1
10
1
manual hook switch - off-hook (pin MHS)
0
1
1
1
10
1
manual hook switch - on-hook (pin MHS)
1
1
1
1
10
1
electronic hook switch - off-hook (pin EHS)
0
1
1
1
10
1
electronic hook switch - on-hook (pin EHS)
Line Events
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AS2540 has 3 inputs, namely MHS (Manual Hook Switch),
EHS (Electronic Hook Switch) and RFD (Ring Frequency
Detector), which sense the state of the two hook-switches
and discriminate an applied ring signal. The MHS is
connected to the manual hook switch which is operated by
the handset and the EHS is connected to an electronic
hook switch which is operated by the CPU. Whenever the
state of these inputs changes, AS2540 immediately sends
<LineEvent> to the CPU after a debounce time. MHS and
EHS up-debouncing lasts 15ms, down-debouncing lasts
85ms. RFD start to discriminate the ring frequency
immediately but will send a <LineEvent> message with a
delay of 102ms. A status change of MHS and EHS pins
must not change the momentary selected path of the
speech network.
Te
ch
The <LineEvent>-message is sent without consideration of
the momentary activities of AS2540 in order to meet PTT
requirements (e.g. line break signalling). The code for the
<LineEvent>-message is chosen with regard to the
minimum current consumption in order to operate the
optocouplers. Pending <Ack>-messages will be queued
after the <LineEvent>-message. An already running
transmissions of <Ack> will not be interrupted and
<LineEvent> will be sent afterwards in this case.
Mode transitions
Idle → BM → MPM → Idle
AS2540 always starts up in backup mode and is prepared
to act like an independent dialler. <LineEvent> is sent to
the CPU and AS2540 remains in back-up mode until any
-
Revision 3.1
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Status of AS2540
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Protocol
Remark
valid message is sent from the CPU. This makes sure that
a non-operable CPU does not disable basic dialling
functions.
- Mode transition
MPM → BM
A watchdog timer is started after <LineEvent> and is reset
whenever AS2540 receives a message from the CPU via
the serial interface. If the CPU does not send any further
valid message within 2400ms, AS2540 goes back into
back-up mode, immediately locks the UART and remains in
backup mode till next on-hook.
Dialling Functions
DTMF
The DTMF generator provides 8 frequencies (in Hz):
11
22
33
697+1209
697+1336
697+1477
44
55
66
770+1209
770+1336
770+1477
77
88
99
852+1209
852+1336
852+1477
**
00
##
941+1209
941+1336
941+1477
Page 8 of 18
austriamicrosystems
Data Sheet AS2540
FLASH timing
CPU can control the DPn pin and the MASK-mode of
AS2540 via serial interface.
Tone Ringer
Toner ringer melody
The
-
3 basic melody frequencies are:
F1=880Hz
F2=1067Hz
F3=1333Hz
The repetition rate is set to 4 which means that the
sequence of F1, F2, F3, F1, F2, F3 is repeated 4 times
within a second.
Keyboard connections
Ring frequency discrimination
PIN
MODE
PIN
C2
1
4
7
*
2
5
8
0
PIN
C3
3
6
9
#
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R1
PIN
C1
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The ring frequency discrimination assures that only signals
with a frequency between 13Hz and 70Hz are regarded as
valid ring signals.
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The MF output levels are set to -4/-6dB which should allow
efficient backup dialling under all line conditions. The
TONE/PAUSE ratio is 90ms/90ms. The preemphasis
between low group and high group frequencies is t.m.
2.6dB.
When a valid ring signal is present for 102ms continuously,
the ring melody generator is activated and remains active
as long as a valid ring signal is present.
Once the ring melody generator has started, the ring signal
is continuously monitored and the ring melody generator is
instantly turned off according to the momentary presence
of a valid or invalid ring signal until next off-hook.
R2
c1
C2
PIN
R1
PIN
R2
C3
Te
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Double contacts under keys 0-9*#: One contact is
connected to AS2540, the other one to CPU.
Revision 3.1
Page 9 of 18
austriamicrosystems
Data Sheet AS2540
Timing diagrams (unscaled)
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Dialling - MF mode
Revision 3.1
Page 10 of 18
austriamicrosystems
Data Sheet AS2540
Electrical characteristics
Electrical characteristics are measured with the Test Circuit application. Typical mean values will not be tested.
Absolute maximum ratings
Positive Supply Voltage
-0.3V <= V DD <= 7V
+/- 25mA
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Input Current
Input Voltage (LS)
-0.3V <= V in <= 10V
Input Voltage (LI, CS)
-0.3V <= V in <= 8V
Input Voltage (STB, RI)
-2V <= V in <= V DD +0.3V
-0.3V <= V in <= V DD +0.3V
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Digital Input Voltage
+/- 800V
Electrostatic Discharge (HBM 1.5kΩ-100pF)
-65°C to +125°C
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Storage Temperature
Recommended operating conditions
Supply Voltage (generated internally)
3.6V <= V DD <= 5V
Oscillator Frequency
Resonator Murata CSA 3.58MG312AM
Operating Temperature
3.58MHz
-15°C to +60°C
DC characteristics
Parameter
I DD
Operating Current
V LI
Conditions
Min
Speech Mode
Speech Mode with SI
MF Dialling
LD Dialling, V DD =2.5V
Ring Mode, V DD =2.5V
ca
Symbol
ni
I Line =15mA w/o operation of SI through optocouplers, unless other specified
Revision 3.1
Units
Test
3
5
4
200
300
5
mA
mA
mA
µA
µA
Y
N
N
N
N
4.5
4.8
V
Y
15mA<=I LINE <=100mA
Output Current, Sink CS,
DPn, MO
TXD
V OL =0.4V
V OL =10mA
1
10
mA
mA
N
N
V OH =V DD -0.4V
-1
mA
N
Output Current, Source MO
Te
I OH
Max
Line Voltage
ch
I OL
4.2
Typ
Page 11 of 18
austriamicrosystems
Data Sheet AS2540
Transmit characteristics
Parameter
Conditions
Min
Typ
A MTX
Transmit Gain
M1/M2 —> LS
Z AC(syn) =1000Ω
+36.5
A TTX
Transmit Gain
TIT —> LS
Z AC(syn) =1000Ω
+6.5
THD
Distortion
V LS =0.25V RMS
V AGC
Soft Clip Level
M1/M2 —> LS at LS
2.0
A SCO
Soft Clip Overdrive
M1/M2
20
Z IN
Input Impedance
M1/M2 - TIT
20
V NO
Noise Output Voltage
LS
T AMP =25°C
RL
Return Loss
Z AC(syn) =1000Ω
18
Conditions
Min
Typ
+38
Max
+39.5
+8
+9.5
Test
dB
Y
dB
Y
%
Y
VP
N
dB
N
lv
2
Units
al
id
Symbol
am
lc s
on A
te G
nt
st
il
kΩ
-72
N
dBmp
Y
dB
Y
Max
Units
Test
Receive characteristics
Parameter
A HRX
Receive Gain
LS —> ROH
Z AC(syn) =1000Ω
+0.5
+2
+3.5
dB
Y
A TRX
Receive Gain
LS —> ROT
Z AC(syn) =1000Ω
-3.5
-2
-0.5
dB
Y
Y
THD
Distortion
V LS =0.25V RMS
2
%
Y
V AGC
Soft Clip Level
ROH
1
VP
N
A SCO
Soft Clip Overdrive
ROH
10
dB
N
dBmp
Y
kΩ
N
ni
Noise Output Voltage
ROH - ROT
ch
V NO
ca
Symbol
Input Imp. RI
ST
Sidetone
Te
Z IN
RL
Revision 3.1
Return Loss
T AMP =25°C
-72
8
V RI <=0.25V RMS
24
dB
Y
Z AC(syn) =1000Ω
18
dB
Y
Page 12 of 18
austriamicrosystems
Data Sheet AS2540
LD characteristics
Parameter
Conditions
t(td)
Flash Duration
DPN pin status can be directly
controlled via serial interface
Min
Typ
Max
Min
Typ
Max
DTMF characteristics
Symbol
Parameter
Conditions
V MFlow
Tone Level Low Group
LS
∆V L-H
Preemphasis L-H
UFC
Unwanted Frequency
Components
∆f
Frequency Deviation
t(td)
Tone Duration
80
t(itp)
Inter Tone Pause
80
t(mo)
Mute Overhang
V CT-H
Comfort Tone (DTMF)
2.0
2.6
Units
Test
dBm
Y
3.2
dB
Y
-40
-46
-52
-58
-70
-80
dBm
dBm
dBm
dBm
dBm
dBm
Y
Y
Y
Y
Y
Y
1.2
%
Y
82.3
85
ms
Y
82.3
85
ms
Y
6
ms
Y
dB
N
am
lc s
on A
te G
nt
st
il
300Hz - 4.3kHz
4.3kHz - 7kHz
7kHz - 10kHz
10kHz - 14kHz
14kHz - 28.5kHz
28.5kHz – 40kHz
ROH rel. to LS
Test
lv
-6
Units
al
id
Symbol
-30
Symbol
Parameter
f1
Conditions
Typ
Max
Units
Test
Frequency 1
770
800
830
Hz
Y
f2
Frequency 2
1025
1067
1110
Hz
Y
f3
Frequency 3
1280
1333
1385
Hz
Y
f MIN
Min. Det. Frequency
12
13
14
Hz
Y
f MAX
Max. Det. Frequency
68
70
75
Hz
Y
t DT
Detection Time
ms
N
Initially
102
Te
ch
ca
Min
ni
Ringer characteristics
Revision 3.1
Page 13 of 18
austriamicrosystems
Data Sheet AS2540
Serial Interface
Conditions
Min
Typ
t RXD-r
RXD signal rise time
V dd =4V,R Pull-up =1.2kΩ
t RXD-f
RXD signal fall time
V comp
Input comparator level at
RXD
BR RXD
RXD baud rate
+/-2%
9600
BR TXD
TXD baud rate
+/-2%
9600
Max
Units
Test
30
µs
N
30
µs
N
V dd /2
V
N
al
id
Parameter
bps
N
bps
Y
Miscellaneous
am
lc s
on A
te G
nt
st
il
lv
Symbol
Parameter
tD
Key Debouce Time
t time-out
Watch-dog Timer
Conditions
Min
Typ
Max
Units
Test
15
ms
N
2400
ms
N
Te
ch
ni
ca
Symbol
Revision 3.1
Page 14 of 18
austriamicrosystems
Data Sheet AS2540
Te
ch
ni
ca
am
lc s
on A
te G
nt
st
il
lv
al
id
Typical Application
Revision 3.1
Page 15 of 18
austriamicrosystems
Data Sheet AS2540
Test Circuit
U1
R1
C1
15
RFD
M1
R2
100n
13
330k
1k
AC
C2
M2
R3
LS
ROH
C3
6
9
140
RI
C4
100u
10u
R4
5
C5 100n
LI
TIT
30
1
C7
STB
ROT
10
1u
9k
C8
10u
D1
Q1
BC327
10V
3
ILine
8
AC
CS
AS2540
CI
lv
C11
10n
AC
R7
2
100u
R8
600
R5
100
R6
300
C6
al
id
7
100n
14
C3
C2
R9
6k
C1
23
22
20
am
lc s
on A
te G
nt
st
il
R1
24
R2
16
R10
17
R11
18
330k
MODE
19
DPn
EHS
MHS
TxD
330k
27
26
OSC
AGND
25
4
12
VSS
MO
VDD
RxD
11
28
21
AS2540
D2
Y1
C9
100u
C10
22u
3.58MHz
Te
ch
ni
ca
5V6
Revision 3.1
Page 16 of 18
austriamicrosystems
Data Sheet AS2540
Packaging
Ordering Information
The device is available in the packages outlined below (not
to scale). For exact mechanical package dimensions
please see austriamicrosystems AG packaging information.
18.1mm / 713mil
7.6mm / 300mil
1.27mm / 50mil
–
–
–
–
–
–
–
–
–
–
–
–
–
–
TIT
STB
CS
VSS
LI
RI
LS
CI
ROH
ROT
VDD
AGD
M1
M2
ni
Marking
MO
TxD
RxD
OSC
C3
C2
C1
R2
R1
MODE
MHS
EHS
DPn
RFD
ch
YYWWAAA
AS2540
Austria
year of production
calendar week of production
ams AG assembly ID
Te
YY
WW
AAA
Revision 3.1
–
–
–
–
–
–
–
–
–
–
–
–
–
–
28
27
26
25
24
23
22
21
20
19
18
17
16
15
ca
1
2
3
4
5
6
7
8
9
10
11
12
13
14
AS2540T
SOIC28
plastic small outline package 28 leads (suffix T)
AS2540Q
Dice-on-Foil
dice
Devices sold by austriamicrosystems AG are covered by
the warranty and patent identification provisions appearing
in its Term of Sale. austriamicrosystems 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.
austriamicrosystems 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 austriamicrosystems 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 austriamicrosystems AG for each
application.
am
lc s
on A
te G
nt
st
il
Pin-out
Description
lv
Max. Body Length
Max. Body Width
Pitch
Package
al
id
28-pin plastic SOIC (suffix T)
Number
Copyright
Copyright © 1997-2002, austriamicrosystems AG, Schloss
Premstaetten, 8141 Unterpremstaetten, Austria-Europe.
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.
The information furnished here by austriamicrosystems AG
is believed to be correct and accurate. However,
austriamicrosystems AG shall not be liable to recipient or
any third party for any damages, including but not limited
to personal injury, property damage, loss of profits, loss of
use, interruption of business or indirect, special, incidental
or consequential damages, of any kind, in connection with
or arising out of the furnishing, performance or use of the
technical data herein. No obligation or liability to recipient
or any third party shall arise or flow out of
austriamicrosystems AG rendering of technical or other
services.
Page 17 of 18
austriamicrosystems
Data Sheet AS2540
Contact
Headquarters
al
id
austriamicrosystems AG
Communications Business Unit
A 8141 Schloss Premstätten, Austria
T. +43 (0) 3136 500 0
F. +43 (0) 3136 525 01
www.austriamicrosystems.com
Sales Offices
USA (east)
austriamicrosystems Germany GmbH
Tegernseer Landstrasse 85
D-81539 München, Germany
Phone: +49/89/693643-0
Fax: +49/89/693643-66
austriamicrosystems USA, Inc.
Suite 400, 8601 Six Forks Road
Raleigh, NC 27615, USA
Phone: +1/919/676 5292
Fax: +1/919/676 5305
France
United Kingdom
am
lc s
on A
te G
nt
st
il
lv
Germany
austriamicrosystems France S.a.r.l.
124, Avenue de Paris
F-94300 Vincennes, France
Phone: +33/1/43 74 00 90
Fax: +33/1/43 74 20 98
austriamicrosystems UK, Ltd.
Coliseum Business Centre, Watchmoor Park
Camberley, Surrey, GU15 3YL, UK
Phone: +44/1276/23 3 99
Fax: +44/1276/29 3 53
Italy
Japan
Switzerland
ca
austriamicrosystems Italy S.r.l.
Via Leone Tolstoi, 64
I-20146 Milano, Italy
Phone: +39/0242/36713
Fax: +39/0242/290889
ch
ni
austriamicrosystems Switzerland AG
Rietstrasse 4
CH-8640 Rapperswil, Switzerland
Phone: +41/55/220 9000
Fax: +41/55/220 9001
USA (west)
Te
austriamicrosystems USA, Inc.
Suite 116, 4030 Moorpark Ave,
San Jose, CA 95117, USA
Phone: +1/408/345 1790
Fax: +1/408/345 1795
Revision 3.1
austriamicrosystems AG
Shin Yokohama Daini, Center Bldg. 10F
3-19-5, Shin Yokohama
Kohoku-ku, Yokohama 222-0033, Japan
Phone: +81/45/474 0962
Fax: +81/45/472 9845
Distributors & Representatives
austriamicrosystems AG is represented by distributors in
the following countries. Please contact your nearest
regional sales office for the distributor address:
Spain, Israel, Korea, Hong-Kong, Taiwan, Malaysia,
Singapore, India, Brazil
Application Support
Please contact your local sales office or your distributor.
Page 18 of 18