2400 BPS Surface-Mount Modem

XE2422H Septembeer 2005 Low-Cost, 2400 BPS Surface-Mount Modem Description XE2422H is a complete miniature, surface-mount, 2400 bps modem. It permits the designer to easily incorporate dial-up communications into set top box, security, vending, or point-of-sale applications. XE2422H is not just a modem chip. The only design requirements are a serial port connection to the micro-controller and the connection to the telephone line. The XE2422H includes transferable FCC Part 68 Registration eliminating FCC Part 68 testing for the Xecom customer. With the XE2422H, Xecom lowers the total cost of modem ownership. As a complete modem, it dramatically reduces modem development and certification costs. Assembly costs are reduced as dozens of components are replaced with this single, surface-mount module. And since Xecom tests 100% of all modules, quality is also improved. The cost of the XE2422H is under nine dollars in 100,000 piece quantities. Contact Xecom for pricing at other quantities Features • • Small Size: 1.60” by 0.80” by 0.152” Data transfer rates from 300 bps to 2400 bps 212A modem protocols • Supports V.21, V.22, V.22bis, V.23, Bell 103, Bell • V.22/Bell 212 Fast Connect • Supports Pulse and FSK Alarm formats • • • • • • • • • • Serial data rates to 115,200 bps. Control and configuration via AT Commands. 3.3 and 5 volt compatible Serial Interface Shared Line Features prevent interference with voice communications on an extension telephone. Complete integrated DAA. User Transferrable FCC Part 68 Registration UL60950 Recognition Low Operating Power, 3.3 Volts, <30 mW; Sleep Mode with Wake-on-Ring feature; Power Down reduces current draw to 100 µA XE2422H BLOCK DIAGRAM /Reset TXD RXD /DCD /CTS /INT ROM Modem Controller Analog Front End Telephone Line Interface (DAA) Tip Ring /RI XECOM (1) XE2422H XE2422H Mechanical Specifications A E D F I F J B (bottom) F C G H Inches Dimension A B C D E F G H I J Min 1.595 0.795 0.147 0.095 0.055 0.095 1.045 0.495 0.995 0.395 Typ 1.600 0.800 0.152 0.100 0.060 0.100 1.050 0.500 1.000 0.400 Max 1.605 0.805 0.157 0.105 0.065 0.105 1.055 0.505 1.005 0.405 Min 40.51 20.19 3.73 2.41 1.40 2.41 26.54 12.57 25.27 10.03 Millimeters Typ 40.64 20.32 3.86 2.54 1.52 2.54 26.67 12.70 25.40 10.16 Max 40.77 20.45 3.99 2.67 1.65 2.67 26.80 12.83 25.53 10.29 XECOM (2) XE2422H XE2422H Pin Configuration Top View Tip Ring 1 2 13 /DCD /DTR /RI Reserved GND 3 4 5 6 7 12 11 10 9 8 VCC /INT /CTS /RESET RXD TXD Note: Pin 1 is marked with a white circle on the top of the module Pin Descriptions PIN 1 NAME Tip DESCRIPTION The Ring and Tip signals connect the modem 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 public switched telephone lines. The XE2422H operates regardless of the polarity of this voltage. The “Battery” voltage drives up to 120 milliampere of DC loop current. UL60950 requires minimum creepage and clearances distances between the Tip and Ring traces and all other circuits. Clearance is the shortest distance between conductive circuits; creepage is the distance between conductive points along the surface 2 Ring The Ring and Tip signals connect the modem 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 public switched telephone lines. The XE2422H operates regardless of the polarity of this voltage. The “Battery” voltage drives up to 120 milliampere of DC loop current. UL60950 requires minimum creepage and clearances distances between the Tip and Ring traces and all other circuits. Clearance is the shortest distance between conductive circuits; creepage is the distance between conductive points along the surface. XECOM (3) XE2422H XE2422H Pin Descriptions (continued) PIN 3 NAME /DCD DESCRIPTION /DCD is an active low output from the modem that indicates the presence of a valid carrier signal. The SE2 register controls /DCD in the XE2422H. The default state is for /DCD to be disabled ATSE2=04 enables /DCD. /DTR is an active low input to the modem. The operation of /DTR is controlled by register SE2 and is normally disabled. When enabled, the modem will exit data mode and enter command mode if /DTR is removed while the modem is on-line. In Pulse and FSK Alarm modes raising /DTR is the only was to disconnect the data link. The /RI signal reports on the presence of an incoming ring signal. When a ring occurs across Tip and Ring, the /RI output goes low and toggles with the cadence of the ring signal. /RI is controlled by register S0D bit 6. The default condition is for /RI to be disabled. Reserved for future use Ground provides the reference voltage for all host interface signals. TXD provides the path for transmitted data and modem commands to be passed from the host controller to the modem. A logic high on TXD represents a “Mark” condition and a logic low represents a “Space” condition. RXD provides the path for received data and modem responses to be sent from the modem to the host controller. A logic high on RXD represents a “Mark” condition and a logic low represents a “Space” condition. /RESET is an active low input which initiates a modem hardware reset. /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. /INT provides an active low hardware interrupt signal from the XE2422H. The operation of this interrupt pin is programmable using registers SE2 and S08. /INT can be programmed to indicate Loss of Carrier, Wake-on-Ring, Loss of Loop Current, or Shared Line Activity. Once triggered the /INT line remains active until cleared by the AT:I command. VCC provides 3.3 volt power to the modem. 4 /DTR 5 /RI 6 7 8 Reserved Ground TXD 9 RXD 10 11 12 /RESET /CTS /INT 13 VCC XECOM (4) XE2422H XE2422H Electrical Specifications Parameter VCC ICC Min 3.0 Typ 3.3 8 7 .1 Max 3.6 Units Volts mA mA mA Comments On Line Sleep Power Down Type B Ringer Type B Ringer Ring Voltage Detected Ring Frequency Detected Telephone Loop Current Line Impedance Data Transmit level DTMF Transmit Level Voh V ol Vih Vil 26 15.3 16 40 600 150 68 120 VRMS Hz ma Ohms -9.0 -2.5 2.4 0.4 2.0 -0.3 5.0 0.8 0 dBm dBm Volts Volts Volts Volts Avg over 3 second interval XE2422H ABSOLUTE MAXIMUM RATINGS Storage Temperature 1 -25O C to +85O C 0O C to +70O C 90 seconds 120 to 180 seconds Maximum Operating Temperature Range Maximum Time Above Eutectic (183O C) Preheat Dwell Time XECOM (5) XE2422H XE2422H Surface-Mount Soldering Instructions The XE2422H is subject to damage if overexposed 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. Maximum Temperature Maximum Time at 220O C Maximum Time above Eutectic (180O C) Maximum Preheat Dwell Time 220O C 20 Seconds 90 Seconds 180 Seconds Maximum Recommended Solder Temperature Profile 220O C 180O C 150O C -20 sec------------------------------180 sec max------------------------max ----- 90 sec max ----- XECOM (6) XE2422H XE2422H Typical Connection Diagram To Host Serial Port VCC XE2422H VCC /DCD /CTS RXD TXD /RI /Reset /INT GND RJ11 F1 RING TIP (22) To System Reset To System Interrupt C1 C2 Parts List for XE2422H Typical Connection Diagram Reference Designation C1, C2 F1 Qty 2 1 Description Cap. 1000 pfd, 1500V minimum PTC, TR600-150 Notes: 1 Capacitors, C1 and C2, may be required for EMI filtering in your system. Without these components you may experience unintended radiation when the telephone cable is attached. C1 and C2 are highvoltage capacitors. We recommend the Johanson Dielectrics 502S47N102KV6T. This 1000 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. F1 is a positive thermal coefficient (PTC) device which protects the modem from excessive current flow. These devices are required for your system to pass UL60950. Fuses may be used in place of the PTC’s XECOM (7) XE2422H XE2422H Shared Line Features The XE2422H monitors line conditions before, after, and during calls. This allows conflicts with other equipment connected to the telephone line to be avoided. The XE2422H includes two Shared Line Features; Connect Detect and Handset Interrupt. Connect Detect Register SDB stores the XE2422H on-hook telephone line voltage. The modem checks the value of register SDB before going off-hook to avoid interrupting a call in progress. The typical value for telephone line voltage while on-hook is 48 volts. A lower voltage level indicates that the line is either disconnected from the modem or is currently in use. Register SDB is an 8 bit register. It stores the loop voltage as a 2’s complement number with each bit representing 1 volt. The Most Significant Bit represents the polarity of the loop voltage. Handset Interrupt: Handset Interrupt permits the modem to yield the phone line when other equipment on the line goes off-hook. This prevents the modem from blocking outgoing emergency calls when the telephone line is shared as in residential use. The modem monitors loop current while it is off-hook. The loop current will drop if another device on the line goes off-hook. Register SF3 holds the loop current value in 1.1 milliamp increments. The XE2422H updates SF3 regularly. The loop current value stored in SF3 is compared to the values of registers S11 and S12.