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MT88E41
CMOS
Extended Voltage Calling Number
Identification Circuit (ECNIC)
Data Sheet
Features
•
•
•
•
•
•
•
•
•
•
1200 baud BELL 202 and CCITT V.23 Frequency
Shift Keying (FSK) demodulation
Compatible with Bellcore GR-30-CORE and SR-
TSV-002476
High input sensitivity: -36dBm minimum FSK
Detection Level
Simple serial 3-wire data interface eliminating the
need for a UART
Power down mode
Internal gain adjustable amplifier
Carrier detect status output
Uses 3.579545 MHz crystal
2.7 - 5.5V operation
Low power CMOS technology
DS5717
Issue 3
February 1998
Ordering Information
MT88E41AE 16 Pin Plastic DIP
MT88E41AS 16 Pin SOIC
MT88E41AN 20 Pin SSOP
-40
°C
to +85
°C
Description
The MT88E41 Extended Voltage Calling Number
Identification Circuit (ECNIC) is a CMOS integrated
circuit providing an interface to various calling line
information delivery services that utilize 1200 baud
BELL 202 or CCITT V.23 FSK voiceband data
transmission schemes. The ECNIC receives and
demodulates the signal and outputs data into a simple
3-wire serial interface.
Typically, the FSK modulated data containing
information on the calling line is sent before alerting the
called party or during the silent interval between the first
and second ring using either CCITT V.23
recommendations or Bell 202 specifications.
The ECNIC accepts and demodulates both CCITT V.23
and BELL 202 signals. Along with serial data and clock,
the ECNIC provides a data ready signal to indicate the
reception of every 8-bit character sent from the Central
Applications
•
Calling Number Delivery (CND), Calling Name
Delivery (CNAM) and Calling Identity on Call
Waiting (CIDCW) features of Bellcore CLASS
SM
service
Feature phones
Phone sets, adjunct boxes
FAX machines
Telephone answering machines
Database query systems
Battery powered applications
•
•
•
•
•
•
GS
IN-
IN+
-
+
Receive
Bandpass
Filter
FSK
Demodulator
Data and Timing
Recovery
DATA
DR
DCLK
CAP
VRef
Bias
Generator
Carrier
Detector
CD
Clock
Generator
to other
circuits
PWDN
OSC1 OSC2
VSS
VDD IC1
IC2
Figure 1 - Functional Block Diagram
CLASS
SM
is a service mark of Bellcore
SEMICMF.019
1
MT88E41
Data Sheet
Office. The received data can be processed externally by a microcontroller, stored in memory, or displayed as
is, depending on the application.
IN+
IN-
GS
VRef
CAP
OSC1
OSC2
VSS
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VDD
IC2
IC1
PWDN
CD
DR
DATA
DCLK
16 PIN PLASTIC DIP/SOIC
IN+
IN-
GS
VRef
CAP
NC
OSC1
NC
OSC2
VSS
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
VDD
IC2
NC
NC
IC1
PWDN
CD
DR
DATA
DCLK
20 PIN SSOP
Figure 2 - Pin Connections
Pin Description Table
Pin
#
Name
16
1
2
3
4
5
6
7
8
9
20
1
2
3
4
5
7
9
10
11
IN+
IN-
GS
V
Ref
Non-inverting Op-Amp (Input).
Inverting Op-Amp (Input).
Gain Select (Output).
Gives access to op-amp output for connection of feedback
resistor.
Voltage Reference (Output).
Nominally V
DD/2
. This is used to bias the op-amp
inputs.
Description
CAP
Capacitor.
Connect a 0.1µF capacitor to V
SS
.
OSC1
Oscillator (Input).
Crystal connection. This pin can be driven directly from an
external clocking source.
OSC2
Oscillator (Output).
Crystal connection. When OSC1 is driven by an external
clock, this pin should be left open.
V
SS
Power supply ground.
DCLK
Data Clock (Output).
Outputs a clock burst of 8 low going pulses at 1202.8Hz
(3.5795MHz divided by 2976). Every clock burst is initiated by the DATA stop bit
start bit sequence. When the input DATA is 1202.8 baud, the positive edge of each
DCLK pulse coincides with the middle of the data bits output at the DATA pin. No
DCLK pulses are generated during the start or stop bits. Typically, DCLK is used to
clock the eight data bits from the 10 bit data word into a serial-to-parallel converter.
DATA
Data (Output).
Serial data output corresponding to the FSK input and switching at
the input baud rate. Mark frequency at the input corresponds to a logic high, while
space frequency corresponds to a logic low at the DATA output. With no FSK
input, DATA is at logic high. This output stays high until CD has become active.
DR
Data Ready (Open Drain Output).
This output goes low after the last DCLK pulse
of each word. This can be used to identify the data (8-bit word) boundary on the
serial output stream. Typically, DR is used to latch the eight data bits from the
serial-to-parallel converter into a microcontroller.
Carrier Detect (Open Drain Output).
A logic low indicates that a carrier has been
present for a specified time on the line. A time hysteresis is provided to allow for
momentary discontinuity of carrier.
10
12
11
13
12
14
CD
2
SEMICMF.019
Data Sheet
Pin Description Table (continued)
Pin
#
Name
16
13
14
15
16
20
15
16
19
20
6, 8, 17, 18
Description
MT88E41
PWDN
Power Down (Input).
Active high, Schmitt Trigger input. Powers down the device
including the input op-amp and the oscillator.
IC1
IC2
V
DD
NC
Internal Connection 1.
Connect to V
SS
.
Internal Connection 2.
Internally connected, leave open circuit.
Positive power supply voltage.
No Connection.
SEMICMF.019
3
MT88E41
1.0
Functional Description
Data Sheet
The MT88E41 Extended Voltage Calling Number Identification Circuit (ECNIC) is a device compatible with the
Bellcore proposal (GR-30-CORE) on generic requirements for transmitting asynchronous voiceband data to
Customer Premises Equipment (CPE) from a serving Stored Program Controlled Switching System (SPCS) or a
Central Office (CO). This data transmission technique is applicable in a variety of services like Calling Number
Delivery (CND), Calling Name Delivery (CNAM) or Calling Identity Delivery on Call Waiting (CIDCW) as specified in
Custom Local Area Signalling Service (CLASS
SM
) calling information delivery features by Bellcore.
With CND, CNAM and CIDCW service, the called subscriber has the capability to display or to store the information
on the calling party which is sent by the CO and received by the ECNIC.
In the CND service, information about a calling party is embedded in the silent interval between the first and second
ring. During this period, the ECNIC receives and demodulates the 1200 baud FSK signal (compatible with Bell-202
specification) and outputs data into a 3-wire serial interface.
In the CIDCW service, information about a second calling party is sent to the subscriber, (while the subscriber is
engaged in another call). During this period, the ECNIC receives and demodulates the FSK signal as in the CND
case.
The ECNIC is designed to provide the data transmission interface required for the above service at the called
subscriber location either in the on-hook case as in CND, or the off-hook case, as in CIDCW. The functional
block diagram of the ECNIC is shown in Figure 1. Note however, for CIDCW applications, a separate CAS (CPE
Alerting Signal) detector is required.
C1
R1
IN+
IN-
C2
R4
R5
GS
R3
R2
V
Ref
DIFFERENTIAL INPUT AMPLIFIER
MT88E41
C1 = C2 = 10 nF
R1 = R4 = R5 = 100 kΩ
R2 = 60kΩ, R3 = 37.5 kΩ
R3 = (R2R5) / (R2 + R5)
INPUT IMPEDANCE
VOLTAGE GAIN
(A
V
diff) = R5/R1
(Z
IN
diff) = 2 R1
2
+ (1/ωC)
2
Figure 3 - Differential Input Configuration
4
SEMICMF.019
单片机
