Page 1
XECOM XEV90
56 KBPS DAA in a PLCC Package
XEV90
7-99
Figure 1: XEV90 BLOCK DIAGRAM
Line Trans-
former
Line Current
Holding Cir-
cuit
Hookswitch
Ring De-
tector
T1
T2
OH(+)
RI(+)
Tip
Ring
Low
Impedance
Dialing
MUTE
L1
L2
Billing Tone
Filter
(Optional)
Description
Xecom’s XEV90 is a complete DAA integrated into a
compact PLCC package. The XEV90 supports analog
data transfer to 56 KBPS. The 68-Pin PLCC package
permits automated, high-volume assembly.
The XEV90 does not sacrifice performance for small size
and surface-mount convenience. The heart of the XEV90
is a proprietary, low profile, low distortion transformer.
This wide bandwidth, low distortion device provides the
clear signal path required for 56 KBPS analog data
transfer.
Like all Xecom DAA's the XEV90 is a complete
telephone line interface. It includes the telephone line
transformer, line current holding circuit, hookswitch and
ring indicator. The XEV90 replaces the dozens of
components found in a discrete DAA design.
Features
* Package: 68-Pin PLCC (only 18 pins used)
dimensions 0.952 inches by 0.952 inches by 0.170
inches high
* Meets Total Harmonic Distortion requirements for
reliable 56 Kbps modems (-85 dB typical);
* Integrated Low-Distortion T elephone Line
Transformer
* Integrated Ring Detection with active high and
active low ouput signals
* Operates on either a single Power Supply of +5 or
+ 3 Volts;
* Solid-State Hookswitch Control with active high
and active low inputs;
* FCC Part 68 Compliant;
* Extended Temperature Range available;
OH(-)
RI(-)
DC2
DC1
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XECOM (2) XEV90
Figure 2: XEV90 Pin Configuration
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
RI(-)
RI(+)
OH(+)
T1
T2
/Mute
OH(-)
VCC
Gnd
N/C
Ring
Tip
N/C
L2
L1
N/C
DC1
DC2
XEV90
(top)
Pin Descriptions
PIN NAME DESCRIPTION
1 N/C No Connection
2 Ring Ring is one wire of the two-wire telephone line connection (RJ11 Pin 4). FCC Part 68 Rules require a
1500 volt isolation barrier between the telephone line and all other circuits. This isolation must be
preserved throughout the system. Xecom recommends 0.100 inch spacing between traces connected to
Ring and all other conductors to preserve this isolation.
3 Tip Tip is one wire of the two-wire telephone line connection (RJ11 Pin 3). The telephone company places
a DC "Battery" voltage across Tip and Ring on all public switched telephone lines. The XEV90 accepts
this line battery voltage without regard to its polarity.
4 N/C No Connection
5, 6 L1 & L2 L1 and L2 provide the connective points for a billing tone filter when required.
7 N/C No Connection
8, 9 DC1 & DC2 DC1 and DC2 control performance of the line current holding circuit. A jumper from DC1 to DC2
limits DC loop current to 60 milliamps. An open circuit between DC1 and DC2 permits loop currents up
to 100 milliamps as required for North America. A resistor may be placed between DC1 and DC2 to
alter the off-hook impedence to meet unique country requirements.
10 GND Ground connection to the XEV90. This signal provides the reference for the OH output and RI input.
This pin should be connected to the systems digital ground.
11 VCC +5 Volt power source for the XEV90. VCC powers the RI and OH control lines.
12 OH(-) Modem switch-hook control: OH(-), an active low input, for controls the switch hook in the XEV90.
When the host activates pin 12, the switch-hook closes and the XEV90 seizes the local telephone line.
Pin 16 provides an active high switch-hook control. OH(-) should remian open when using OH(+).
The host can pulse OH(-) line to perform rotary dialing. The normal pulse rate is ten pulses per second.
Closing the switch-hook creates a series of pulses. Dial one pulse for the digit one to ten pulses for the
digit zero. The pulses on OH(-) must be asymmetrical, active for thirty-one milliseconds, inactive for
sixty-nine milliseconds. An inter-digit delay of at least one hundred milliseconds is required.
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Pin Descriptions
PIN NAME DESCRIPTION
13 Mute The Mute signal can be used for pulse (rotary) dialing. The host must toggle the Mute signal to generate
the dialing pulses.
14 T2 T2 in conjunction with T1 provides the differential input/output for the analog signal. T2 connects
directly to the secondary side of the miniature line transformer embedded into the XEV90. T o match the
impedance of the DAA to the 600 ohm telephone line, a 320 ohm resistor must be connected in series
with T1 or T2.
15 T1 T1 in conjunction with T2 provides the differential input/output for the analog signal. T1 connects
directly to the secondary side of the miniature line transformer embedded into the XEV90. T o match the
impedance of the DAA to the 600 ohm telephone line, a 320 ohm resistor must be connected in series
with T1 or T2.
16 OH(+) Switch-hook control to the modem. OH(+) provides an active high input for controlling the switch
hook. When pin 16 is active, the switch-hook closes and the XEV90 seizes the local telephone line.
OH(+) should remain open when using OH(-).
The host can pulse OH(+) line to perform rotary dialing. The normal pulse rate is ten pulses per second.
Closing the switch-hook creates these pulses. Dial one pulse for the digit one to ten pulses for the digit
zero. The pulses on OH(+) must be asymmetrical, active for thirty-one milliseconds, inactive for sixty-
nine milliseconds. An inter-digit delay of at least one hundred milliseconds is required.
17 RI(+) Ring Indicate output from the modem. RI(+) is an active high, open-emmitter output. RI(+) provides
a square wave representation of the Ring signal present across Tip and Ring. This permits intelligent
monitoring of the incoming ring. The XEV90 recognizes ring voltages of thirty-eight to one hundred
fifty volts RMS in the frequency range of sixteen to sixty-eight Hertz. When using the RI(+) output,
a 20 Kohm pull-down resistor must be added to RI(+); RI(-) must be tied to VCC.
18 RI(-) Ring Indicate output from the modem. RI(-) is an active low, open collector output. RI(-) provides
a square wave representation of the Ring signal present across Tip and Ring. This permits intelli-
gent monitoring of the incoming ring. The XEV90 recognizes ring voltages of thirty-eight to one
hundred fifty volts RMS in the frequency range of sixteen to sixty-eight Hertz. Pin 17 provides an
active high ring indication. When using the RI(-) output, a 20 Kohm pull-up resistor must be added
to RI(-); RI(+) must be tied to ground.
XECOM (3) XEV90
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XECOM (4) XEV90
Electrical Specification (Vcc=+5v ±10%, Ta=0 to 70 deg C)
Power Supply Current Off-hook 10 mA
On-hook 0.5 mA
Transmit Insertion loss 600 Ohm Impedance, 1800 Hz 4.5 6.0 7.0 dB
Receive Insertion loss 600 Ohm Impedance, 1800 Hz 4.5 6.0 7.0 dB
Line Matching Impedance Input to T1 and T2 300 320 340 ohms
Line Impedance 320 ohm matching impedance resistor 540 600 660 ohms
Total Harmonic Distortion 600 Ohm Impedance, 100 to 4000 Hz -8 0 -85 dB
Ring Detect Sensitivity Min. AC voltage between Tip & 20 150 Vrms
Ring Type B ringer
Ring Frequencies Detected 16 68 Hz
RI Output Voltage Ring signal present, Active low 0.2 0.5 Volts
Ring signal present, Active High 2.0 5.0 Volts
Hook-Switch Control ON: (off-hook) 0.2 0.5 Volts
Voltage (active high) OFF: (on-hook) 2.0 3.0 Volts
Hook-Switch Control ON: (off-hook) 2.0 3.0 Volts
Voltage (active low) OFF: (on-hook) 0.2 0.5 Volts
Hook-Switch Control ON: (off-hook) 5 10 milliamps
Current OFF: (on-hook) 5 microamps
Loop Current No Connection from DC1 to DC2 20 100 mA
(current draw from line) DC1 shorted to DC2 10 60
DC On-Hook Impedance Hookswitch Open 10 MOhms
Parameter Conditions Min Typ Max Units
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Mechanical Specifications
XECOM (5) XEV90
A
A1
D3
a
h x 45 degrees
(3 Places)
D2
b
e
D1
D1
D
Index Corner
J x 45 degrees
Inches Millimeters
Dim Min Ref Max Min Ref Max
A 0.170 4.32
A1 0.020 0.51
b 0.017 0.021 4.32 5.33
D 0.985 0.995 25.0 25.27
D1 0.952 24.18
D2 0.800 20.32
D3 0.910 0.930 23.1 23.62
e 0.100 2.54
h 0.010 0.25
J 0.045 1.15
a45
O
45
O
coplanarity 0.004 0.10
(top)
10
1
9
(bottom)
XEV90 ABSOLUTE MAXIMUM RATINGS
Storage T emperature -25O C to +85O C
Operating T emperature Range * 0O C to +70O C
Maximum Solder T emperature 220O C
Maximum Time Above Eutectic (183O C) 90 seconds
Preheat Dwell Time 120 to 180 seconds
* The XEV90 can be ordered with an Operating T emperature of -40O C to +85O C at extra cost.
Order XEV90-ITR to specify Industrial Temperature Range (ITR).
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XECOM (6) XEV90
Typical Connection Diagram
RJ11
1 RI(-) 18
2 Ring RI(+) 17
3 Tip OH(+) 16
4 T1 15
5 L2 T2 14
6 L1 /Mute 13
7 OH(-) 12
8 DC1 VCC 11
9 DC2 Gnd 10
L1
XEV90
J1
RingD
TXA1
Rin
VC
TXA2
+5V
FB1
FB2
RV1
320 ohms
10K
RC336ACF
-OH
Notes on Application Schematic:
The Schematic above shows connections to support North American regulations. Use in North America requires
compliance with FCC Part 68 Rules.
When jumper J1 is installed loop current is limited to just 60 milliamps. J1 must be removed for FCC Part 68
compliance.
L1 provides the Billing Tone Filter required in some countries.
C1 and C2 are 47 picofarad 1500 Volt Capacitors provided for EMI filtering. High voltage capacitors are required to
maintain the isolation barrier between the telephone line and the host equipment.
FB1 and FB2 are Ferrite beads. They provide EMI filtering. They should present an impedance of at least 100 ohms
at 100 MHz.
R V1 protects the XEV90 from voltage surges generated by near lightning strikes. Xecom recommends a Teccor
Electronics P3100BA70 Sidactor. This device has a typical breakover voltage of 300 volts.
The 320 ohm resistor between T1 and TXA1 provides the optimal resistance for the XEV90 to match the impedance
of a standard 600 ohm line.
The Mute signal can be used to provide low-impedance pulse dialing.
C1
C2
Telin
20K
+5V
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XECOM (7) XEV90
Application Notes
Dialing:
The public switched telephone network permits tone and rotary
(pulse) dialing. The XEV90 supports both types of dialing.
Tone dialing requires an external signal source to provide the
dialing tones. Rotary dialing is accomplished by pulsing the
OH or Mute line on the XEV90.
Pulse Dialing: The XEV90 generates dialing pulses through
momentary closures of the switch-hook. (pulsing of the MUTE
signal can also be used to generate dialing pules) Each digit is
represented as a series of pulses, one pulse for a one to ten
pulses for a zero. The pulse rate in normally ten pulses per
second. (Some European countries require 20 pulses per
second.) The dialing pulses are asymmetrical. Consult with the
local country regulations for the required duty cycle. An
interdigit delay of at least one hundred milliseconds separates
the digits.
Tone Dialing: To tone dial the XEV90 seizes the line, OH
active. For each digit a unique DTMF, Dual Tone Multiple
Frequency, tone pair is placed across T1 and T2. The higher
frequency tone is always of greater magnitude than the lower
frequency tone. Transmit the tones for a minimum of 70
milliseconds, and leave a minimum of 70 milliseconds between
digits.
The table below shows the correct DTMF signal frequencies for
each digit.
Digit Lower Tone Upper Tone
1 697 1209
2 697 1336
3 697 1477
4 770 1209
5 770 1336
6 770 1477
7 852 1209
8 852 1336
9 852 1477
0 941 1336
* 941 1209
# 941 1477
Signal Levels:
FCC Part 68 Rules set the allowable signal level
in the US for all signals placed on the telephone line other than
live voice. Other countries have similar regulations. Signal
levels are measured in dBm. Zero dBm is 1 milliwatt through a
600 ohm load.
Insertion Loss: There is some loss of signal power as the
information signal passes through the XEV90. This "insertion"
loss should be taken into account when placing signals across
T1 and T2 for transmission. The typical insertion loss of the
XEV90 is 6 dBm.
Total Harmonic Distortion:
Total Harmonic Distortion is the most common measure of the
signal path quality provided by the DAA. The primary sources
of distortion in the DAA are the Telephone Line Transformer
and the Line Current Holding Circuit, although board layout
and other factors can introduce distortion.
Total Harmonic Distortion varies with frequency. The voice
band provided by the telephone line is limited to less than 4000
Hz. High speed modems such as 33.6 KBPS and 56KBPS
require virtually all of this bandwidth for signal transmission.
Even if the Total Harmonic Distortion of a device is very good
in the center portion of the spectrum, signal quality is compromised if distortion greatly increases at the outer limits of the
voice band.
Note: This chart represents the total harmonic distortion of the
complete DAA not just the telephone line transformer.
Distortion measurements of the transformer only will
show much lower distortion but do not account for
distortion from other sources.
50
55
60
65
70
75
80
85
90
50 100 200 500 1000 1 500 2000 4000
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XECOM (8) XEV90
XEV90
2/4 Wire Conversion:
Full Duplex communications over a two-wire telephone line
requires that transmit and receive signal share the available
bandwidth. The two-to-four wire convertor separates these
signals at the host interface. Most modem analog front end
chips incorporate an internal 2/4 wire convertor making it
unnecessary to provide one in the DAA.
If you are using the XEV90 for an application other than a
modem, such as voice processing, or your modem analog front
end does not provide the 2/4 wire convertor, you will need to
provide a discrete 2/4 wire convertor. The schematic on this
page shows a simple 2/4 wire convertor circuit.
The performance of the 2/4wire convertor is measured by its
Transhybrid Loss. The Transhybrid Loss shows how much the
2/4 wire convertor attenuates the transmit signal on the received
data line. The circuit above provides a typical Transhybrid Loss
of 20 dB.
The Transhybrid Loss will vary with the quality of the
impedance match to the telephone line. Even when the
recommended value for the impedance matching resistor, R6,
is used variations from line to line alter the impedance match.
The value of R3 can be changed to improve the Transhybrid
Loss.
The 2/4 wire convertor also amplifies the transmit and receive
signals to compensate for the insertion loss of the DAA. This
circuit provides 6 dB gain of both the transmit and receive
signals. The values of R1 and R2 set the transmit gain. The
values of R4 and R5 set the receive gain.
2/4 Wire Convertor
R6
R2
R1
R3
R4
R5
4558
4558
10K
11.5K
40K
320 ohms
20K
T1
T2
Transmit
Receive
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XECOM (9) XEV90
Telephone Line Connection Information
When developing a product to be connected to the telephone line, it is necessary to use a circuit known as a Data
Access Arrangement (DAA) approved by the appropriate governmental agency . In the US this agency is the Federal
Communications Commission (FCC), while in Canada it is Industry Canada (IC). These agencies test and approve
the product to ensure that it meets their specifications, thereby protecting the telephone system from damage and
protecting the user from high voltage transients (such as lightning strikes) which may come down the telephone line.
The XEV90 has been designed to meet all FCC Part 68 requirements for hazardous voltage, line impedance and
leakage current. If the system transmits data, synthesized voice, or DTMF tones on the telephone line, the user must
certify that the signals transmitted meet basic FCC requirements for maximum transmission levels, out of band energy
and billing delay. Full details may be obtained from the FCC under Part 68 of the FCC Rules and Regulations, or in
Title 47 of the Code of Federal Regulations, however the basic requirements are as follows:
1. Maximum Transmit Level
For the normal “permissive” (standard) telephone line, equipment which transmits data (such as a modem) must not
exceed a transmission level of -9 dBm.
2. Out of Band Energy
Data equipment must not transmit “out of band” energy on the telephone line which exceeds the following limits:
Frequency Range Max. Power
3995 Hz to 4005 Hz -27 dBm
4005 Hz to 12 kHz -20 dBm
12 kHz to 90 kHz -55 dBm
90 kHz to 270 kHz -55 dBm
270 kHz to 6 MHz -15 dBm
3. DTMF Transmission Level
If the system is capable of DTMF dialing, the maximum DTMF transmission level must be less than 0 dBm averaged
over a 3 second interval.
4. Billing Delay
A delay of 2 seconds or greater is required after the time the XEV90 is taken “off hook” and before any information
is transmitted. This is required to ensure that billing information may be exchanged between telephone company
central offices without interference.
OEM’s using the XEV90 must certify to the FCC that the final system meets the requirements of Part 68 which include
the criteria above as well as the high voltage protection provided by the XEV90. This is generally accomplished
through an independent testing lab which tests the System and submits the proper paperwork to the FCC for approval.
Since the XEV90 already complies with FCC Part 68 rules, this is a relatively simple process.
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XECOM XEV90
Copyright, Xecom © 1999
While Xecom, Inc. has made every effort to ensure that the information presented here is accurate, Xecom will not
be liable for any damages arising from errors or omission of fact. Xecom reserves the right to modify specifications
and/or prices without notice. Product mentioned herein are used for identification purposes only and may be trademarks and/or registered trademarks of their respective companies.
Xecom
Incorporated
374 Turquoise Street, Milpitas, CA 95035
Ph:408-945 -6640 Fax:408 -942-1346
Email: info@xecom.com
Terms of Sale
Devices sold by XECOM are covered by the warranty provisions appearing in its Terms of Sale only. XECOM
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. XECOM makes no warranty of
merchantability or fitness for any purposes. XECOM reserves the right to discontinue production and change
specifications and prices at any time and without notice. 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 and authorization by XECOM for such application.
Xecom assumes no responsibility for the use of any circuitry other than circuitry embodied in a Xecom product.
No other circuits, patents, or licenses are implied.
Life Support Policy
Xecom's products are not authorized for use as Critical Components in Life Support Devices or Systems.
Life Support Devices or Systems are devices or systems which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions provided in the labeling, can be reasonably expected to result in significant injury to the user.
A Critical Component is any component of a life support device or system whose failure to perform can be reasonably expected to cause failure of the life support device or system, or to affect its safety or effectiveness.
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