Cermetek DataSheet for product XE2420

XE2420

March 2002

2400 BPS Surface-Mountable Integrated Sealed-Hybrid Modem

Description

Features

Xecom’s XE2420 provides a complete 2400 BPS

* Small Size: The HyPLCC™ measures less than 1

modem into an inexpensive miniature, surface-mount

inch by 1inch square and 0.290 inches thick

package. Xecom’s new HyPLCC™ package (Hybrid

* Surface-mountabile: The HyPLCC™ package is

PLCC) makes it possible to meet the conflicting goals

equivalent to a 68-Pin PLCC device.

of small size, low cost and surface-mountability. The

* Data transfer at 2400, 1200 and 300 BPS using

XE2420 targets remote monitoring applications in

V.22bis, V.22, V.23, V.21, Bell 202, Bell 212A, and

industrial, commercial and residential locations

Bell 103 Protocols

As a complete modem, the XE2420 includes not only

* Modem Control and Configuration via industry

all modem circuitry but also user transferrable FCC

standard AT Commands.

Part 68 Registration and UL60950 recognition. This

* Supports external shared line features permitting

allows the XE2420 to be safely integrated into your

unobtrusive sharing of a local telephone line.

embedded application.

* Complete integrated DAA includes, Ring Detect,

Xecom’s new HyPLCC™ package infuses the XE2420

Loop Current Holding Circuit, Hook Switch. Metalic

with both its small size and surface mountability. The

Surge Protection, and Telephone Line Transformer

HyPLCC package allows complex hybrid circuits to fit

* User Transferrable FCC Part 68 Registration

the 68-Pin PLCC footprint. The HyPLCC™ package

* UL60950 Recognition

provides a completely sealed enviroment protecting

the XE2420 during assembly and board cleaning

* Low Power operation, 330 milliWatt; Power down

operations.

operation less than 1 microWatt

XE2420 BLOCK DIAGRAM

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XE2420

XE2420 Mechanical Specifications

(TOP)

.050”

45 O

Inches

Millimeters

Dimension

Min

Typ

Max

Min

Typ

Max

0.280

0.285

0.290

7.11

7.24

7.37

0.985

0.990

0.995

25.02

25.15

25.27

0.950

0.955

0.960

24.13

24.26

24.38

0.910

0.920

0.930

23.11

23.37

23.62

0.045

0.050

0.055

1.15

1.27

1.40

0.695

0.700

0.705

17.65

17.78

17.91

0.395

0.400

0.405

10.03

10.16

10.29

i(radius)

0.015

0.020

0.025

0.13

0.25

0.38

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XE2420

XE2420 Pin Configuration

/DCD

/CTS

RESET

/DSR

RING

/RTS

N/C

/DTR

TIP

/RXD

N/C

/TXD

TOP

N/C

/RI

HI3

GND

HI1

N/C

EECL

HI2

EEDT

Vcc

Vui

Pin Descriptions

NAME

DESCRIPTION

/DCD

/DCD is an active low output from the modem. The AT&C command controls when the

XE2420 asserts /DCD.

/CTS

/CTS is an active low output from the modem. The modem asserts /CTS to indicate that it can

accept data from the terminal equipment on /TXD.

RESET

RESET is an active high input which intiates a modem hardware reset. RESET must be active

for a minimum of 100 milliseconds for a proper modem reset sequence. No external reset is

required; if none is used the RESET signal should be left open.

/DSR

/DSR is an active low output from the modem. The AT&S command controls when the XE2420

asserts /DSR.

/RTS

/RTS is an active low input to the modem. /RTS indicates to the modem that the host has data

to send.

/DTR

/DTR is an active low input to the modem. The AT&D command determines how the modem

will interpret activity on /DTR.

/RXD

/RXD provides the path for received data and modem responses to be sent from the modem to

the host terminal equipment.

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XE2420

XE2420 Pin Descriptions (continued)

NAME

DESCRIPTION

/TXD

/TXD provides the path for transmitted data and modem commands to be passed from the host

terminal equipment to the modem.

/RI

The /RI signal reports on the presence of an incoming ring signal. When a ring occurs across

Tip and Ring, the /RI output toggles at the ring frequency. The /RI output is powered by Vui

and therefore operates even when VCC is removed from the modem.

Ground

Ground provides the reference voltage for all host interface signals.

N/C

No internal connection

EECL

EECL provides the clock to the optional external non-volatile memory. The XE2420 requires

a serial 8 by 256 Byte EEPROM for telephone number storage. If the non-volatile memory is

not used, EECL should remain unconnected.

EEDT

EEDT provides the serial data connection for the optional, external non-volatile memory. The

XE2420 requires a serial 8 by 256 Byte EEPROM for telephone number storage. If the non-

volatile memory is not used, EEDT should remain unconnected.

VCC

VCC provides 5 volt power to the modem. The RI output is not powered by VCC but by Vui.

Vui

Vui provides uninterrupted power to the XE2420 ring detect circuit. Placing 5 volt power on

Vui insures that the /RI ouput will operate when VCC is removed from the modem.

HI2

HI2 is one of the four hardware hooks for connecting shared line features to the XE2420.

HI2 interfaces to the 911 Interrupt circuit.

This circuit detects changes in the loop current

when an extension handset is lifted as when making an emergency call. The system host

should immediately abort the modem connection to permit the user to complete their call.

See the Application Note on Page 10 of this data sheet to see how these line monitoring

circuits interface with the XE2420.

CD provides another of the four hardware hooks for connecting shared line features to the

XE2420. CD interfaces to the Connect Dectect circuit. Connect Detect allows the system

host to check the status of the telephone line before going off-hook to initiate a call. If the

phone line is in use,the host can delay its call until the telephone line is free. See the

Application Note on Page 10 of this data sheet to see how these line monitoring circuits

interface with the XE2420.

HI1

HI1 is one of the four hardware hooks for connecting shared line features to the XE2420.

HI1 interfaces to the 911 Interrupt circuit.

This circuit detects changes in the loop current

when an extension handset is lifted as when making an emergency call. The system host

should immediately abort the modem connection to permit the user to complete their call.

See the Application Note on Page 9 of this data sheet to see how these line monitoring

circuits interface with the XE2420.

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XE2420

XE2420 Pin Descriptions (continued)

NAME

DESCRIPTION

HI3

HI3 is one of the four hardware hooks for connecting shared line features to the XE2420.

HI3 interfaces to the 911 Interrupt circuit.

This circuit detects changes in the loop current

when an extension handset is lifted as when making an emergency call. The system host

should immediately abort the modem connection to permit the user to complete their call.

See the Application Note on Page 10 of this data sheet to see how these line monitoring

circuits interface with the XE2420.

N/C

No internal connection, To prevent damage in case of voltage surges on the telephone line, we

recommend that nothing be connected to this pin.

N/C

No internal connection, To prevent damage in case of voltage surges on the telephone line, we

recommend that nothing be connected to this pin.

Tip

The Ring and Tip signals provide modem the connection to the telephone line. 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.

The telephone company places a DC “Battery” voltage across Tip and Ring on all public switched

telephone lines. The XE2420 will operate regardless of the polarity of this “Battery” voltage.

The “Battery” voltage drives up to 100 milliamps of DC loop current.

UL60950 requires minimum creepage and clearances distances be maintained between the

Tip and Ring traces and all other circuits. Clearance is the shortest distance between conductive

circuits; creepage is the distance between conductive surfaces along the surface

N/C

No internal connection, To prevent damage in case of voltage surges on the telephone line, we

recommend that nothing be connected to this pin.

Ring

The Ring and Tip signals provide modem the connection to the telephone line. 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.

The telephone company places a DC “Battery” voltage across Tip and Ring on all public switched

telephone lines. The XE2420 will operate regardless of the polarity of this “Battery” voltage.

The “Battery” voltage drives up to 100 milliamps of DC loop current.

UL60950 requires minimum creepage and clearances distances be maintained between the

Tip and Ring traces and all other circuits. Clearance is the shortest distance between conductive

circuits; creepage is the distance between conductive surfaces along the surface.

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XE2420

XE2420 Soldering Instructions

The XE2420 is subject to damage if over-exposed to heat during solder reflow operations. Following the

soldering instructions below will ensure that the process of soldering the module to the board does not damage the

modem. The XE2420 must not be exposed to direct Infrared (IR) heating. If your process includes direct IR

heating, you must shield the XE2420 from the infrared rays.

Maximum Temperature

220 O C

MaximumTimeat220 O C

20 Seconds

Maximum Time above Eutectic (180 O C)

90 Seconds

MaximumPreheatDwellTime

180 Seconds

Maximum Recommended Solder Temperature Profile

220 O C

180 O C

150 O C

-20 sec-

--------------------------------180secmax---------------------

max

----- 90 sec max -----

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XE2420

XE2420 Electrical Specifications

Parameter

Min

Typ

Max

Units

Comments

VCC

4.75

5.25

Volts

ICC

On Line

ICC

idle

Vui

4.75

5.25

Volts

Iui

µ a

No Ring Signal Present

Ring Voltage Detected

150

RMS

Type B Ringer

Ring Frequency Detected

15.3

Type B Ringer

Connect Detect Sensitivity

Volts DC

Battery Voltage level detected by

circuit shown on Page 10

Handset Interrupt Detection

1.0

Volts DC

Change in Battery Voltage

detected by circuit shown on

Page 10

Telephone Loop Current

100

Line Impedance

600

Ohms

Data Transmit level

-12

-10

-9

dBm

DTMF Transmit Level

-2.5

dBm

Avg over 3 second interval

Voh

2.4

Volts

Vol

0.4

Volts

Vih

2.0

VCC+0.3

Volts

Vil

-0.3

0.8

Volts

XE2420 ABSOLUTE MAXIMUM RATINGS

Storage Temperature

-25 O C to +85 O C

Operating Temperature Range 1

0 O C to +70 O C

Maximum Time Above Eutectic (183 O C)

90 seconds

Preheat Dwell Time

120 to 180 seconds

The XE2420 can be ordered with an Operating Temperature of -40 O C to +85 O C at extra cost. Order XE2420-ITR or

to specify Industrial Temperature Range (ITR).

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XE2420

XE2420 Typical Application Schematic

+5 Volts

NM24C04

20K

VCC

XE2420

SCL

Reset

VSS

SDA

EECL

EEDT

/TXD

RJ11

/TXD

/RXD

FB1

/RTS

RING

16C550

/RI

UART

/DSR

FB2

/DCD

TIP

/CTS

/DTR

+5 Volts

Vcc

Battery

Vui

Gnd

Notes:

FB1 and FB2 are ferrite beads which may be required for EMI filtering in your system. Without these

components you may experience unintended radiation when the telephone cable is attached to your system.

We recommend selecting components such as the TDK ACB2012L-120 which provide a minimum of 100

ohms of impedence at frequencies above 100 MHz.

2. C1 and C2 are high-voltage capacitors which may be required for EMI filtering in your system. Without these

components you may experience unintended radiation when the telephone cable is attached to your system. We

recommend selecting components such as the Panasonic ECKDRS471. This 470 pfd, 3000 volt capacitor will

direct the high frequency harmonics to the system ground. These capacitors must be rated at a minimum of 1500

volts to maintain the isolation required by FCC Part 68 Rules.

3. The Battery applied to Vui allows the XE2420’s Ring Indicate output to remain active even when the modem

itself is powered down. If this power-down mode is not required for your application, Vui should be tied to

VCC.

4. The EEPROM, NM24C04, provides for non-volatile storage of telephone numbers using the AT&Z command.

The EEPROM must be programmed using the Diplomat™ Utility from Zilog Inc.

Diplomat™ is a trademark of Zilog Inc.

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XE2420

Application Note: Using a 68-Pin PLCC Socket

The XE2420 can be inserted into a socket for a 68-pin PLCC device. The HyPLCC package uses only 24 pins; 15

on one side and 9 on the opposite side. Allignment within the socket is critical for all pins of the XE2420 to

make contact with the appropriate pins of the PLCC socket. The drawing below illustrates how the XE2420 can be

inserted into the 68-pin PLCC socket.

XE2420

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XE2420

Application Note: XE2420 Shared Line Feature

For applications where the XE2420 shares a telephone line with a telephone handset, Xecom has provided four

hardware hooks for connecting two monitoring circuits. These circuits monitor the status of the telephone line to

prevent the modem from interfering with a voice call.

The Connect Detection Circuit monitors the telephone loop voltage when the modem is not in use. This allows the

system host to check the status of the telephone line before initiating a call. The ConDetect signal will be be high

when the phone line is available but goes low to indicate that the telephone line is in use.

The Handset Interupt or 911 Interrupt circuit monitors loop current while the modem is in the off-hook state. This

circuit detects the change in loop current which occurs when a handset on the shared telephone line is lifted. The

HSInterrupt output will go low momentarily if the handset is lifted during data communications. The system host can

then immediately abort the modem connection and permit the user to complete their call.

Parts List for Shared Line Feature Application Note

Reference

Designation

Qty

Description

Designation

Qty

Description

C1, C2

Cap. 470 pfd 2600V

Resistor, 56K 5%

Cap. 10 ufd 20% 16V

Resistor, 33K 5%

Cap. 1 Ufd, 20% 10V

Resistor, 402K 5%

F1, F2

PTC, TR600-150

R10

Resistor, 1M 5%

FB1, FB2

Ferrite, ACB2012L-120

R11

Resistor, 1.5K 5%

Trans. FMMT3904

R12

Resistor, 20K 5%

R1, R2

Resistor, 10M 5%

R13

Resistor, 100K 5%

R3, R5, R6

Resistor, 200K 1%

U1, U2

OP Amp, TLC271CD

Resistor, 280K 1%

Opto-coupler, PS2705-1

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XE2420

XE2420 AT Commands

The XE2420 uses "AT" commands for configuration and

Command Buffer -

No more than 36 characters,

control. This section describes use of the AT command

including the AT prefix, may be loaded into the com-

format and lists the AT commands, Registers and Result

mand buffer.

If the command buffer overflows, the

codes. XE2420 "AT" commands have two operational

modem issues an "ERROR" result code and commands

modes; Command Mode and Data Mode.

are not executed.

Data Mode: The XE2420 enters data mode after it

Command Line Editing -

The backspace edits a

connects with a remote modem and issues the appropri-

command line before it is executed. The backspace key,

ate result code. In the Data Mode the modem sends all

(Control and H simultaneously on some systems), erases

data presented on Transmit Data (/TXD) to the remote

the previous character in the command line. Register S5

modem and puts data from the remote modem onto

allows the user to select a character other than a back-

Received Data (/RXD). When the modem exits data

space to edit the command line.

mode, it is