73K302L Bell 212A, 103, 202 Single-Chip Modem April 2000 DESCRIPTION FEATURES The 73K302L is a highly integrated single-chip modem IC which provides the functions needed to construct a Bell 202, 212A and 103 compatible modem. The 73K302L is an enhancement of the 73K212L single-chip modem with Bell 202 mode features added. The 73K302L is capable of 1200 or 0-300 bit/s full-duplex operation over dial-up lines. 4-wire full-duplex capability and a low speed back channel are also provided in Bell 202 mode. The 73K302L recognizes and generates a 900 Hz soft carrier turn-off tone, and allows 103 for 300 bit/s FSK operation. The 73K302L integrates analog, digital, and switched-capacitor array functions on a single substrate, offering excellent performance and a high level of functional integration in a single 28-pin DIP or PLCC package. The 73K302L operates from a single +5V supply with very low power consumption. • One-chip Bell 212A, 103 and 202S/T standard compatible modem data pump • Full-duplex operation at 0-300 bit/s (FSK), 1200 bit/s (DPSK) or 0-1200 bit/s (FSK) forward channel with or without 0-150 bit/s back channel • • Full-duplex 4-wire operation in Bell 202 mode • Interfaces directly with standard microprocessors (8048, 80C51 typical) • • Serial port for data transfer • Call progress, carrier, precise answer tone (2225 Hz), soft carrier turn-off (SCT), and FSK mark detectors • • DTMF, answer, and SCT tone generators • CMOS technology for low power consumption using 60 mW @ 5V from a single power supply The 73K302L includes the DPSK and FSK modulator/demodulator functions, call progress and handshake tone monitors, test modes, and a tone generator capable of producing DTMF, answer, and 900 Hz soft carrier turn-off tone. This device supports Bell 202, 212A and 103 modes of operation, allowing both synchronous and Pin and software compatible with other TDK Semiconductor Corporation K-Series 1-chip modems Both synchronous and asynchronous modes of operation Test modes available: ALB, DL, RDL, Mark, Space, Alternating bit patterns (continued) BLOCK DIAGRAM AD0-AD7 DATA BUS BUFFER DTMF & TONE GENERATORS 8-BIT BUS FSK MODULATOR/ DEMODULATOR FOR PSK MODULATOR/ DEMODULATOR STATUS SERIAL PORT FOR DATA SMART DIALING & DETECT FUNCTIONS TESTS: ALB, DLB RDLB PATTERNS RXD RXCLK CLOCK GENERATOR POWER GND VREF VDD ISET STATUS AND CONTROL LOGIC XTL2 TXD DIGITAL PROCESSING AND XTL1 INT CONTROL TXCLK CLK CS RESET READ WRITE CONTROL LOGIC EXCLK RD WR ALE TRANSMIT FILTER TXA RECEIVE FILTER RXA 73K302L Bell 212A, 103, 202 Single-Chip Modem The SYNC/ASYNC converter also has an extended overspeed mode which allows selection of an output overspeed range of either +1% or +2.3%. In the extended overspeed mode, stop bits are output at 7/8 the normal width. DESCRIPTION (continued) asynchronous communications. The 73K302L is designed to appear to the systems designer as a microprocessor peripheral, and will easily interface with popular one-chip microprocessors (80C51 typical) for control of modem functions through its 8bit multiplexed address/data bus or via an optional serial command bus. An ALE control line simplifies address demultiplexing. Data communications occurs through a separate serial port only. The serial data stream from the transmit buffer or the rate converter is passed through the data scrambler and onto the analog modulator. The data scrambler can be bypassed under processor control when unscrambled data must be transmitted. If serial input data contains a break signal through one character (including start and stop bits) the break will be extended to at least 2 times N + 3 bits long (where N is the number of transmitted bits/character). The 73K302L is ideal for use in either free standing or integral system modem products where multistandard data communications is desired. Its high functionality, low power consumption and efficient packaging simplify design requirements and increase system reliability. A complete modem requires only the addition of the phone line interface, a modem controller, and RS232 level converter for a typical system. Serial data from the demodulator is passed first through the data descrambler and then through the SYNC/ASYNC converter. The ASYNC/ASYNC converter will reinsert any deleted stop bits and output data at an intra-character rate (bit-to-bit timing) of no greater than 1219 bit/s. An incoming break signal (low through two characters) will be passed through without incorrectly inserting a stop bit. Tri-mode capability in one-chip allows full-duplex Bell 212 and 103 operation or assymetrical Bell 202S operation over the 2-wire switched telephone network. 202T mode full-duplex operation at 1200 bit/s is also possible when operating on 4-wire leased lines. SYNCHRONOUS MODE The Bell 212A standard defines synchronous operation at 1200 bit/s. Operation is similar to that of the asynchronous mode except that data must be synchronized to a provided clock and no variation in data transfer rate is allowable. Serial input data appearing at TXD must be valid on the rising edge of TXCLK. A soft carrier turn-off feature facilitates fast line turn around when using the 202S mode for half-duplex applications. The 73K302L is part of TDK Semiconduct K- Series family of pin and function compatible single-chip modem products. These devices allow systems to be configured for higher speeds and Bell or CCITT operation with only a single component change. TXCLK is an internally derived signal in internal mode and is connected internally to the RXCLK pin in slave mode. Receive data at the RXD pin is clocked out on the falling edge of RXCLK. The ASYNCH/SYNCH converter is bypassed when synchronous mode is selected and data is transmitted out at the same rate as it is input. OPERATION ASYNCHRONOUS MODE Data transmission for the DPSK mode requires that data ultimately be transmitted in a synchronous fashion. The 73K302L includes ASYNC/SYNC and SYNC/ASYNC converters which delete or insert stop bits in order to transmit data at a regular rate. In asynchronous mode the serial data comes from the TXD pin into the ASYNC/SYNC converter. The ASYNC/SYNC converter accepts the data provided on the TXD pin which normally must be 1200 bit/s +1.0%, 2.5%. The rate converter will then insert or delete stop bits in order to output a signal which is 1200 bit/s ± .01% (±0.01% is the required synchronous data rate accuracy). DPSK MODULATOR/DEMODULATOR In DPSK mode the 73K302L modulates a serial bit stream into di-bit pairs that are represented by four possible phase shifts as prescribed by the Bell 212A standards. The base-band signal is then filtered to reduce intersymbol interference on the bandlimited 2-wire telephone line. Transmission occurs using either a 1200 Hz (originate mode) or 2400 Hz (answer mode) carrier. Demodulation is the reverse of the modulation process, with the incoming analog 2 73K302L Bell 212A, 103, 202 Single-Chip Modem addressed with the AD0, AD1, and AD2 multiplexed address lines (latched by ALE) and appear to a control microprocessor as four consecutive memory locations. Two control registers and the tone register are read/write memory. The detect register is read only and cannot be modified except by modem response to monitored parameters. signal eventually decoded into di-bits and converted back to a serial bit stream. The demodulator also recovers the clock which was encoded into the analog signal during modulation. Demodulation occurs using either a 1200 Hz carrier (answer mode or ALB originate mode) or a 2400 Hz carrier (originate mode or ALB answer mode). The 73K302L uses a phase locked loop coherent demodulation technique for optimum receiver performance. SERIAL COMMAND INTERFACE MODE The serial command interface allows access to the 73K302L control and status registers via a serial command port. In this mode the AD0, AD1 and AD2 lines provide register addresses for data passed through the data pin under control of the RD and WR lines. A read operation is initiated when the RD line is taken low. The first bit is available after RD is brought low and the next seven cycles of EXCLK will then transfer out seven bits of the selected address location LSB first. A write takes place by shifting in eight bits of data LSB first for eight consecutive cycles of EXCLK. WR is then pulsed low and data transfer into the selected register occurs on the rising edge of WR. FSK MODULATOR/DEMODULATOR The FSK modulator produces a frequency modulated analog output signal using two discrete frequencies to represent the binary data. Bell 103 mode uses 1270 and 1070 Hz (originate, mark and space) or 2225 and 2025 Hz (answer, mark and space). Bell 202 mode uses 1200 Hz (mark) and 2200 Hz (space for the main channel and 387 Hz (mark) and 487 Hz (space) for the back channel. The modulation rate of the back channel is up to 150 baud. Demodulation involves detecting the received frequencies and decoding them into the appropriate binary value. The rate converter and scrambler/descrambler are automatically bypassed in the 103 or 202 modes. SPECIAL DETECT CIRCUITRY The special detect circuitry monitors the received analog signal to determine status or presence of carrier, answer tone and weak received signal (long loop condition), special tones such as FSK marking and the 900 Hz soft carrier turn-off tone are also detected. A highly frequency selective call progress detector provides adequate discrimination to accurately detect lower quality call progress signals. PASSBAND FILTERS AND EQUALIZERS High and low band filters are included to shape the amplitude and phase response of the transmit and receive signals and provide compromise delay equalization and rejection of out-of-band signals in the receive channel. Amplitude and phase equalization are necessary to compensate for distortion of the transmission line and to reduce intersymbol interference in the bandlimited receive signal. The transmit signal filtering approximates a 75% square root of raised Cosine frequency response characteristic. DTMF GENERATOR The DTMF generator will output one of 16 standard tone pairs determined by a 4-bit binary value and TX DTMF mode bit previously loaded into the tone register. Tone generation is initiated when the DTMF mode is selected using the tone register and the transmit enable (CR0 bit D1) is changed from 0 to 1. AGC The automatic gain control maintains a signal level at the input to the demodulators which is constant to within 1 dB. It corrects quickly for increases in signal which would cause clipping and provides a total receiver dynamic range of >45 dB. SOFT CARRIER TURN-OFF TONE GENERATOR The soft carrier turn-off tone generator will output a 900 Hz tone. When activated in Bell 202 main channel transmit mode, the output signal will shift to 900 Hz, maintaining phase continuity during the transition. PARALLEL BUS INTERFACE Four 8-bit registers are provided for control, option select and status monitoring. These registers are 3 73K302L Bell 212A, 103, 202 Single-Chip Modem PIN DESCRIPTION POWER NAME PLCC/PIN DIP NUMBER TYPE DESCRIPTION GND 28 I System Ground. VDD 15 I Power supply input, 5V ±10%. Bypass with 0.1 and 22 µF capacitors to GND. VREF 26 O An internally generated reference voltage. Bypass with 0.1 µF capacitor to GND. ISET 24 I Chip current reference. Sets bias current for op-amps. The chip current is set by connecting this pin to VDD through a 2 MΩ resistor. ISET should be bypassed to GND with a 0.1 µF capacitor. PARALLEL MICROPROCESSOR INTERFACE ALE 12 I Address latch enable. The falling edge of ALE latches the address on AD0-AD2 and the chip select on CS. 4-11 I/O Address/data bus. These bidirectional tri-state multi-plexed lines carry information to and from the internal registers. CS 20 I Chip select. A low on this pin during the falling edge of ALE allows a read cycle or a write cycle to occur. AD0-AD7 will not be driven and no registers will be written if CS (latched) is not active. The state of CS is latched on the falling edge of ALE. CLK 1 O Output clock. This pin is selectable under processor control to be either the crystal frequency (for use as a processor clock) or 16 times the data rate for use as a baud rate clock in DPSK mode only. The pin defaults to the crystal frequency on reset. INT 17 O Interrupt. This open drain output signal is used to inform the processor that a detect flag has occurred. The processor must then read the detect register to determine which detect triggered the interrupt. INT will stay low until the processor reads the detect register or does a full reset. RD 14 I Read. A low requests a read of the 73K302L internal registers. Data cannot be output unless both RD and the latched CS are active or low. RESET 25 I Reset. An active high signal on this pin will put the chip into an inactive state. All control register bits (CR0, CR1, Tone) will be reset. The output of the CLK pin will be set to the crystal frequency. An internal pull down resistor permits power on reset using a capacitor to VDD. AD0-AD7 4 73K302L Bell 212A, 103, 202 Single-Chip Modem PARALLEL MICROPROCESSOR INTERFACE (continued) NAME WR PLCC/PIN DIP NUMBER TYPE 13 I DESCRIPTION Write. A low on this informs the 73K302L that data is available on AD0-AD7 for writing into an internal register. Data is latched on the rising edge of WR. No data is written unless both WR and the latched CS are active low. SERIAL MICROPROCESSOR INTERFACE A0-A2 46 I Register Address Selection. These lines carry register addresses and should be valid during any read or write operation. DATA 11 I/O Serial Control Data. Data for a read/write operation is clocked in or out on the falling edge of the EXCLK pin. The direction of data flow is controlled by the RD pin. RD low outputs data. RD high inputs data. RD 14 I Read. A low on this input informs the 73K302L that data or status information is being read by the processor. The falling edge of the RD signal will initiate a read from the addressed register. The RD signal must continue for eight falling edges of EXCLK in order to read all eight bits of the referenced register. Read data is provided LSB first. Data will not be output unless the RD signal is active. WR 13 I Write. A low on this input informs the 73K302L that data or status information has been shifted in through the DATA pin and is available for writing to an internal register. The normal procedure for a write is to shift in data LSB first on the DATA pin for eight consecutive falling edges of EXCLK and then to pulse WR low. Data is written on the rising edge of WR. Note: The serial control mode is provided by tying ALE high and CS low. In this configuration AD7 becomes the data input and AD0, AD1 and AD2 become the address only. See the SERIAL CONTROL TIMING diagram on page22 5 73K302L Bell 212A, 103, 202 Single-Chip Modem PIN DESCRIPTION (continued) DTE USER INTERFACE NAME PLCC/PIN DIP NUMBER TYPE DESCRIPTION EXCLK 19 I External Clock. This signal is used only in synchronous DPSK transmission when the external timing option has been selected. In the external timing mode the rising edge of EXCLK is used to strobe synchronous DPSK transmit data available on the TXD pin. Also used for serial control interface. RXCLK 23 O Receive Clock. The falling edge of this clock output is coincident with the transitions in the serial received DPSK data output. The rising edge of RXCLK can be used to latch the valid output data. RXCLK will be valid as long as a carrier is present. In Bell 202 mode a clock which is 16 times 1200 or 16 times 150 baud data rate is output. RXD 22 O/ Weak Pull-up Received Data Output. Serial receive data is available on this pin. The data is always valid on the rising edge of RXCLK when in synchronous mode. RXD will output constant marks if no carrier is detected. TXCLK 18 O Transmit Clock.This signal is used only in synchronous DPSK transmission to latch serial input data on the TXD pin. Data must be provided so that valid data is available on the rising edge of the TXCLK. The transmit clock is derived from different sources depending upon the synchronization mode selection. In Internal Mode the clock is 1200 Hz generated internally. In External Mode TXCLK is phase locked to the EXCLK pin. In Slave Mode TXCLK is phase locked to the RXCLK pin. TXCLK is always active. In Bell 202 mode the output is a 16 times 1200 baud clock or 16 times 150 baud to drive a UART. TXD 21 I Transmit Data Input. Serial data for transmission is applied on this pin. In synchronous modes, the data must be valid on the rising edge of the TXCLK clock. In asynchronous modes (1200 or 300 baud) no clocking is necessary. DPSK must be 1200 bit/s +1%, -2.5% or +2.3%, -2.5% in extended overspeed mode. ANALOG INTERFACE AND OSCILLATOR RXA 27 I Received modulated analog signal input from the telephone line interface. TXA 16 O Transmit analog output to the telephone line interface. XTL1 2 I XTL2 3 I These pins are for the internal crystal oscillator requiring a 11.0592 MHz parallel mode crystal and two load capacitors to Ground. XTL2 can also be driven from an external clock. 6 73K302L Bell 212A, 103, 202 Single-Chip Modem REGISTER DESCRIPTIONS microprocessor and the 73K302L internal state. DR is a detect register which provides an indication of monitored modem status conditions. TR, the tone control register, controls the DTMF generator, answer and guard tones and RXD output gate used in the modem initial connect sequence. All registers are read/write except for DR which is read only. Register control and status bits are identified below: Four 8-bit internal registers are accessible for control and status monitoring. The registers are accessed in read or write operations by addressing the A0 and A1 address lines in serial mode, or the AD0 and AD1 lines in parallel mode. The AD0 and AD1 lines are latched by ALE. Register CR0 controls the method by which data is transferred over the phone line. CR1 controls the interface between the REGISTER BIT SUMMARY ADDRESS REGISTER DATA BIT NUMBER AD2 - AD0 D7 D6 D5 D4 D3 D2 D1 D0 TRANSMIT ENABLE ANSWER/ ORIGINATE CONTROL REGISTER 0 CR0 000 MODULATION OPTION 0 TRANSMIT MODE 3 TRANSMIT MODE 2 TRANSMIT MODE 1 TRANSMIT MODE 0 CONTROL REGISTER 1 CR1 001 TRANSMIT PATTERN 1 TRANSMIT PATTERN 0 ENABLE DETECT INTERRUPT BYPASS SCRAMBLER/ ADD PH. EQ. 202 CLK CONTROL RESET TEST MODE 1 TEST MODE 0 DR 010 X X RECEIVE DATA UNSCR. MARKS CARRIER DETECT SPECIAL TONE CALL PROGRESS LONG LOOP TONE CONTROL REGISTER TR 011 RXD OUTPUT CONTROL TRANSMIT SCT TONE TRANSMIT ANSWER TONE TRANSMIT DTMF DTMF3 DTMF/ 202T FDX DTMF1/ OVERSPEED DTMF0/ SPEC. TONE/ ANSWER TONE/ SELECT ID REGISTER ID 110 ID ID ID ID X X X X DETECT REGISTER NOTE: When a register containing reserved control bits is written into, the reserved bits must be programmed as 0's. X = Undefined, mask in software. 7 73K302L Bell 212A, 103, 202 Single-Chip Modem REGISTER ADDRESS TABLE ADDRESS REGISTER CONTROL REGISTER 0 CR0 DATA BIT NUMBER AD2 - AD0 D7 D6 D5 D4 D3 D2 D1 D0 000 MODULATION OPTION 0 TRANSMIT MODE 3 TRANSMIT MODE 2 TRANSMIT MODE 1 TRANSMIT MODE 0 TRANSMIT ENABLE ORIGINATE/ ANSWER 0=103 FSK 1=202 FSK CONTROL REGISTER 1 CR1 001 TRANSMIT PATTERN 1 0000=PWR DOWN 1100=FSK 0010=EXT SYNCH 0011=SLAVE SYNCH 0100=ASYNCH 8 BITS/CHAR 0101=ASYNCH 9 BITS/CHAR 0110=ASYNCH 10 BITS/CHAR 0111=ASYNCH 11 BITS/CHAR 1100=FSK BELL 103 OR 202 TRANSMIT PATTERN 0 00=TX DATA 01=TX ALTERNATE 10=TX MARK 11=TX SPACE DETECT REGISTER DR 010 X X ENABLE DETECT INTERRUPT BYPASS SCRAMBLER/ ADD PH. EQ. 0=DISABLE 1=ENABLE 0=NORMAL 1=BYPASS SCRAMBLER 1=ADD EXTRA PHASE EQ. IN 202 ONLY RECEIVE DATA UNSCR. MARK 0=DISABLE TXA OUTPUT 1=ENABLE TXA OUTPUT CLK CONTROL 0=XTAL 1=16 X DATA RATE OUTPUT AT CLK PIN IN DPSK MODE ONLY CARRIER DETECT OUTPUTS RECEIVED DATA STREAM TONE CONTROL REGISTER TR 011 RXD OUTPUT CONTROL RXD PIN 0=NORMAL 1=TRI STATE TRANSMIT SCT TONE 0=OFF 1=ON TRANSMIT ANSWER TONE 0=OFF 1=ON RESET 0=NORMAL 1=RESET SPECIAL TONE TEST MODE 1 10 110 00XX=73K212AL, 322L, 321L 01XX=73K221AL, 302L 10XX=73K222AL, 222BL 1100=73K224L 1110=73K324L 1100=73K224BL 1110=73K324BL ID CALL PROGRESS TEST MODE 0 LONG LOOP 0=CONDITION NOT DETECTED 1=CONDITION DETECTED TRANSMIT DTMF DTMF3 0=DATA 1=TX DTMF DTMF2/ 202T FDX DTMF1/ OVERSPEED 4 BIT CODE FOR 1 OF 16 DUAL TONE COMBINATIONS.0=1% 1=2.5% ID IN 202 MODE: 0=RECEIVE @ 1200 BIT/S, TRANSMIT @ 150 BIT/S 1=RECEIVE @ 150 BIT/S, TRANSMIT @ 1200 BIT/S 00=NORMAL 01=ANALOG LOOPBACK 10=REMOTE DIGITAL LOOPBACK 11=LOCAL DIGITAL LOOPBACK 0=NORMAL 1=FULL DUPLEX IN 202 MODE ID REGISTER IN 212, 103 MODES: 0=ANSWER 1=ORIGINATE ID ID X = Undefined, mask in software 0 = Only write zeros to this location 8 X X X DTMF0/ SPECIAL TONE 0=900 HZ SCT TONE IF IN ANSWER MODE =2225 HZ ANSWER TONE IN 103 OR 212 ORIGINATE MODES 1=FSK MARK X 73K302L Bell 212A, 103, 202 Single-Chip Modem CONTROL REGISTER 0 CR0 000 D7 D6 D5 D4 D3 D2 D1 D0 MODUL. OPTION 0 TRANSMIT MODE 3 TRANSMIT MODE 2 TRANSMIT MODE 1 TRANSMIT MODE 0 TRANSMIT ENABLE ANSWER/ ORIGINATE BIT NO. D0 NAME CONDITION DESCRIPTION Answer/ Originate 0 Selects answer mode in 103 and 212A modes (transmit in high band, receive in low band) or in Bell 202 mode, receive at 1200 bit/s and transmit at 150 bit/s. 1 Selects originate mode in 103 and 212A modes (transmit in low band, receive in high band) or in Bell 202 mode, receive at 150 bit/s and transmit at 1200 bit/s. Note: This bit works with TR bit D0 to program special tones detected in Tone Register. See detect and tone registers. D1 Transmit Enable 0 Disables transmit output at TXA. 1 Enables transmit output at TXA. Note: Answer tone and DTMF TX control require TX enable. D5, D4,D3, D2 Transmit Mode D5 D4 D3 D2 0 0 0 0 Selects power down mode. All functions disabled except digital interface. 0 0 0 1 Internal synchronous mode. In this mode TXCLK is an internally derived 1200 Hz signal. Serial input data appearing at TXD must be valid on the rising edge of TXCLK. Receive data is clocked out of RXD on the falling edge of RXCLK. 0 0 1 0 External synchronous mode. Operation is identical to internal synchronous, but TXCLK is connected internally to EXCLK pin, and a 1200 Hz ± 0.01% clock must be supplied externally. 0 0 1 1 Slave synchronous mode. Same operation as other synchronous modes. TXCLK is connected internally to the RXCLK pin in this mode. 0 1 0 0 Selects DPSK asynchronous mode - 8 bits/character (1 start bit, 6 data bits, 1 stop bit). 0 1 0 1 Selects DPSK asynchronous mode - 9 bits/character (1 start bit, 7 data bits, 1 stop bit). 0 1 1 0 Selects DPSK asynchronous mode - 10 bits/character (1 start bit, 8 data bits, 1 stop bit). 0 1 1 1 Selects DPSK asynchronous mode - 11 bits/character (1 start bit, 8 data bits, Parity and 1 or 2 stop bits). 1 1 0 0 Selects 103 or 202 FSK operation. 9 73K302L Bell 212A, 103, 202 Single-Chip Modem CONTROL REGISTER 0 (continued) CR0 000 D7 D6 D5 D4 D3 D2 D1 D0 MODUL. OPTION 0 TRANSMIT MODE 3 TRANSMIT MODE 2 TRANSMIT MODE 1 TRANSMIT MODE 0 TRANSMIT ENABLE ANSWER/ ORIGINATE BIT NO. NAME CONDITION D6 0 D7 Modulation Option DESCRIPTION Not used; must be written as a “0.” D7 D5 D4 X 0 X DPSK asynchronous mode at 1200 bit/s. 0 1 1 FSK Bell 103 mode. 1 1 1 FSK Bell 202 mode. Selects: CONTROL REGISTER 1 CR1 001 D7 D6 D5 D4 D3 D2 D1 D0 TRANSMIT PATTERN 1 TRANSMIT PATTERN 0 ENABLE DETECT INTER. BYPASS SCRAMB/ ADD PH. EQ. CLK CONTROL RESET TEST MODE 1 TEST MODE 0 BIT NO. NAME D1, D0 Test Mode D2 Reset CONDITION DESCRIPTION D1 D0 0 0 Selects normal operating mode. 0 1 Analog loopback mode. Loops the transmitted analog signal back to the receiver, and causes the receiver to use the same center frequency as the transmitter. To squelch the TXA pin, transmit enable must be forced low. Not supported in FDX202 mode. 1 0 Selects remote digital loopback. Received data is looped back to transmit data internally, and RXD is forced to a mark. Data on TXD is ignored. 1 1 Selects local digital loopback. Internally loops TXD back to RXD and continues to transmit carrier from TXA pin. 0 Selects normal operation. 1 Resets modem to power down state. All control register bits (CR0, CR1, Tone) are reset to zero. The output of the CLK pin will be set to the crystal frequency. 10 73K302L Bell 212A, 103, 202 Single-Chip Modem CONTROL REGISTER 1 (continued) CR1 001 BIT NO. D3 D4* D5 D7, D6 D7 D6 D5 D4 D3 D2 D1 D0 TRANSMIT PATTERN 1 TRANSMIT PATTERN 0 ENABLE DETECT INTER. BYPASS SCRAMB/ ADD PH. EQ. CLK CONTROL RESET TEST MODE 1 TEST MODE 0 NAME CONDITION CLK Control 0 Selects 11.0592 MHz crystal echo output at CLK pin. 1 Selects 16 times the data rate, output at CLK pin in DPSK modes only. Bypass Scrambler/ Add Phase Equalization 0 Selects normal operation. DPSK data is passed through scrambler. 1 Selects Scrambler Bypass. DPSK data is routed around scrambler in the transmit path. In Bell 202 mode, additional phase equalization is added to the main channel filters when D4 is set to 1. Enable Detect 0 Disables interrupt at INT pin. 1 Enables INT output. An interrupt will be generated with a change in status of DR bits D1-D4. The special tone and call progress detect interrupts are masked when the TX enable bit is set. Carrier detect is masked when TX DTMF is activated. All interrupts will be disabled if the device is in power down mode. Transmit Pattern DESCRIPTION D7 D6 0 0 Selects normal data transmission as controlled by the state of the TXD pin. 0 1 Selects an alternating mark/space transmit pattern for modem testing. 1 0 Selects a constant mark transmit pattern. 1 1 Selects a constant space transmit pattern. * D4 should always be set to 1 when receiving 1200 bit/s data and to 0 when transmitting 1200 bit/s data in 202 mode. 11 73K302L Bell 212A, 103, 202 Single-Chip Modem DETECT REGISTER DR 010 BIT NO. D0 D1 D2 D7 D6 D5 D4 D3 D2 D1 D0 X X RECEIVE DATA UNSCR. MARK CARR. DETECT SPECIAL TONE CALL PROG. LONG LOOP NAME CONDITION DESCRIPTION Long Loop 0 Indicates normal received signal. 1 Indicates low received signal level. Call Progress Detect 0 No call progress tone detected. 1 Indicates presence of call progress tones. The call progress detection circuitry is activated by energy in the normal 350 to 620 Hz call progress band. Special Tone Detect 0 No special tone detected as programmed by CR0 bit D0 and Tone Register bit D0. 1 Special tone detected. The detected tone is: (1) 2225 Hz answer tone if D0 of TR=0 and the device is in Bell 103 or 212A originate mode. (2) Soft carrier turn-off tone if D0 of TR=0 and the device is in Bell 202 answer mode. (3) An FSK mark in the mode the device is set to receive if D0 of TR is set to 1. Tolerance on special tones is ±3%. D3 D4 D5 D6, D7 Carrier Detect 0 No carrier detected in the receive channel. 1 Indicated carrier has been detected in the received channel. Unscrambled Mark Detect 0 No unscrambled mark. 1 (DPSK only) Indicates detection of unscrambled marks in the received data. A valid indication requires that unscrambled marks be received for > 165.5 ±6.5 ms. Receive Data Not Used Continuously outputs the received data stream. This data is the same as that output on the RXD pin, but it is not disabled when RXD is tri-stated. Undefined Mask in software 12 73K302L Bell 212A, 103, 202 Single-Chip Modem TONE REGISTER TR 011 D7 D6 D5 D4 D3 D2 D1 D0 RXD OUTPUT CONTR. TRANSMIT SOFT CARRIER TURN-OFF TONE TRANSMIT ANSWER TONE TRANSMIT DTMF DTMF 3 DTMF 2/ 202 FDX DTMF 1/ OVERSPEED DTMF 0/ SPECIAL TONE SEL BIT NO. D0 NAME CONDITION DESCRIPTION DTMF 0/ Special Tone D5 D4 D0 D0 interacts with bits D5, D4, and CR0 as shown. 0 1 X Transmit DTMF tones. Detect/Select 0 0 0 2225 Hz answer tone will be detected in D2 of DR if originate mode is selected in CR0. 900 Hz SCT tone will be detected in D2 of DR if Bell 202 answer mode is selected in CR0. D1 D2 D3, D2, D1, D0 DTMF 1/ Overspeed X 0 1 Mark of an FSK mode selected in CR0 is to be detected in D2 of DR. 1 0 0 2225 Hz answer tone will be generated when in answer mode and transmit enable is selected in CR0. 1 0 1 2100 Hz answer tone will be generated when in answer mode and transmit enable is selected in CR0. D4 D1 0 0 Asynchronous DPSK 1200 bit/s +1.0% -2.5%. 0 1 Asynchronous DPSK 1200 bit/s +2.3% -2.5%. DTMF2/202T FDX DTMF 3, 2, 1, 0 D1 interacts with D4 as shown. 0 Enables 202 half-duplex operation if TR D4 = 0 1 Enables 202 full-duplex operation if TR D4 = 0 D3 D2 D1 D0 0 1 0 1 0 1 01 Programs 1 of 16 DTMF tone pairs that will be transmitted when TX DTMF and TX enable bit (CR0, bit D1) are set. Tone encoding is shown below: KEYBOARD EQUIVALENT 13 DTMF CODE D3 D2 D1 D0 TONES LOW HIGH 1 0 0 0 1 697 1209 2 0 0 1 0 697 1336 3 0 0 1 1 697 1477 4 0 1 0 0 770 1209 5 0 1 0 1 770 1336 6 0 1 1 0 770 1477 7 0 1 1 1 852 1209 8 1 0 0 0 852 1336 9 1 0 0 1 852 1477 0 1 0 1 0 941 1336 73K302L Bell 212A, 103, 202 Single-Chip Modem TONE REGISTER (continued) TR 011 D7 D6 D5 D4 D3 D2 D1 D0 RXD OUTPUT CONTR. TRANSMIT SOFT CARRIER TURN-OFF TONE TRANSMIT ANSWER TONE TRANSMIT DTMF DTMF 3 DTMF 2/ 202 FDX DTMF 1/ OVERSPEED DTMF 0/ SPECIAL TONE SEL BIT NO. NAME CONDITION D3, D2, D1, D0(cont.) D4 D5 D6 D7 DESCRIPTION KEYBOARD EQUIVALENT DTMF CODE D3 D2 D1 D0 TONES LOW HIGH * 1 0 1 1 941 1209 # 1 1 0 0 941 1477 A 1 1 0 1 697 1633 B 1 1 1 0 770 1633 C 1 1 1 1 852 1633 D 0 0 0 0 941 1633 Transmit DTMF 0 Disable DTMF. 1 Activate DTMF. The selected DTMF tones are transmitted continuously when this bit is high. TX DTMF overrides all other transmit functions. Transmit Answer Tone 0 Disables answer tone generator. 1 Enables answer tone generator. A 2225 Hz answer tone will be transmitted continuously when the transmit enable bit is set. To transmit answer tone, the device must be in answer mode. Transmit SCT Tone 0 Disables SCT tone generator. 1 Transmit SCT tone in Bell 202 mode. To transmit SCT tone, 202 originate mode must be selected. RXD Output Control 0 Enables RXD pin. Receive data will be output on RXD. 1 Disables RXD pin. The RXD pin reverts to a high impedance with internal weak pull-up resistor. Notes for Tone Register use: 1. To detect SCT tone, 202 answer mode must be selected. 2. For answer tone detection, 103 or 212 originate mode must be active. To transmit answer tone, the 73K302L must be in 103 or 212 answer mode. 3. After completion of DTMF dialing, bit D2 should be reset unless 202 full-duplex mode is selected. 14 73K302L Bell 212A, 103, 202 Single-Chip Modem ID REGISTER ID 110 D7 D6 D5 D4 D3 D2 D1 D0 ID ID ID ID X X X X BIT NO. D7, D6, D5, D4 D3-D0 NAME CONDITION Device Identification Signature D7 D6 D5 D4 Not Used DESCRIPTION Indicates Device: 0 0 X X 73K212AL, 73K321L or 73K322L 0 1 X X 73K221AL or 73K302L 1 0 X X 73K222AL , 73K222BL 1 1 0 0 73K224L 1 1 1 0 73K324L 1 1 0 0 73K224BL 1 1 1 0 73K324B L Undefined Mask in software 15 73K302L Bell 212A, 103, 202 Single-Chip Modem ELECTRICAL SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS PARAMETER RATING VDD Supply Voltage 7V Storage Temperature -65 to 150°C Soldering Temperature (10 sec.) 260°C Applied Voltage -0.3 to VDD+0.3V Note: All inputs and outputs are protected from static charge using built-in, industry standard protection devices and all outputs are short-circuit protected. RECOMMENDED OPERATING CONDITIONS PARAMETER MIN NOM MAX UNIT VDD Supply voltage 4.5 5 5.5 V TA, Operating Free-Air Temp. -40 +85 °C -0.01 +0.01 % Clock Variation CONDITION (11.0592 MHz) Crystal or external clock External Components (Refer to Application section for placement.) VREF Bypass Capacitor (External to GND) 0.1 Bias setting resistor (Placed between VDD and ISET pins) 1.8 ISET Bypass Capacitor (ISET pin to GND) 0.1 µF VDD Bypass Capacitor 1 (External to GND) 0.1 µF VDD Bypass Capacitor 2 (External to GND) 22 µF XTL1 Load Capacitor Depends on crystal characteristics; from pin to GND XTL2 Load Capacitor 16 µF 2 2.2 40 20 MΩ pF 73K302L Bell 212A, 103, 202 Single-Chip Modem DC ELECTRICAL CHARACTERISTICS (TA = -40°C to 85°C, VDD = recommended range unless otherwise noted.) PARAMETER CONDITION MIN IDD, Supply Current ISET Resistor = 2 MΩ NOM MAX UNIT 8 12 mA IDDA, Active CLK = 11.0592 MHz IDD1, Power-down CLK = 11.0592 MHz 4 mA IDD2, Power-down CLK = 19.200 kHz 3 mA Digital Inputs VIH, Input High Voltage Reset, XTL1, XTL2 3.0 VDD V All other inputs 2.0 VDD V 0 0.8 V 100 µA VIL, Input Low Voltage IIH, Input High Current VI = VIH Max IIL, Input Low Current VI = VIL Min -200 Reset Pull-down Current Reset = VDD 1 Input Capacitance All Digital Input Pins µA 50 µA 10 pF VDD V Digital Outputs VOH, Output High Voltage IOH MIN = -0.4 mA 2.4 VOL, Output Low Voltage IO MAX = 1.6 mA 0.4 V VOL, CLK Output IO = 3.6 mA 0.6 V RXD Tri-State Pull-up Curr. RXD = GND -50 µA CMAX, CLK Output Maximum Capacitive Load 15 pF Inputs Capacitance, all Digital Input pins 10 pF XTL1, 2 Load Capacitors Depends on crystal 60 pF CLK Maximum Capacitive Load 15 pF -1 Capacitance 17 15 73K302L Bell 212A, 103, 202 Single-Chip Modem ELECTRICAL SPECIFICATIONS (continued) DYNAMIC CHARACTERISTICS AND TIMING (TA = -40°C to +85°C, VDD = recommended range unless otherwise noted.) PARAMETER CONDITION MIN NOM MAX UNIT DPSK Modulator Carrier Suppression Measured at TXA 45 Output Amplitude TX scrambled marks -11.5 Output Freq. Error CLK = 11.0592 MHz -0.35 Transmit Level Transmit Dotting Pattern -11.5 -11.9 dB -10 -9 dBm0 +0.35 % -10 -9 dBm0 -10.9 -9.9 dBm0 THD in the alternate band DPSK or FSK -60 -50 dB Output Bias Distortion Transmit Dotting Pattern In ALB @ RXD ±3 Total Output Jitter Random Input in ALB @ RXD DTMF Generator Must not be in 202 mode FSK Modulator Soft Carrier Turnoff Tone Harmonic Distortion in 700-2900 Hz band Freq. Accuracy % -10 +10 % -0.25 +0.25 % Output Amplitude, Low group DPSK mode -10 -9 -8 dBm0 Output Amplitude, High group DPSK mode -8 -7 -6 dBm0 Twist High-Band to Low-Band 1.0 2.0 3.0 dB Long Loop Detect With Sinusoid -38 -28 dBm0 Dynamic Range Refer to Performance Curves Note: 45 Parameters expressed in dBm0 refer to the following definition: 0 dB loss in the Transmit path from TXA to the telephone line. 2 dB gain in the Receive path from the telephone line to RXA. Refer to the Basic Box Modem diagram in the Applications section for the DAA design. 18 dB 73K302L Bell 212A, 103, 202 Single-Chip Modem DYNAMIC CHARACTERISTICS AND TIMING (continued) PARAMETER CONDITION MIN Detect Level -3 dB points in 285 and 675 Hz -38 Reject Level Test signal is a 460 Hz sinusoid Delay Time -70 dBm0 to -30 dBm0 STEP Hold Time -30 dBm0 to -70 dBm0 STEP NOM MAX UNIT Call Progress Detector Hysteresis dBm0 -45 dBm0 20 40 ms 20 40 ms 2 dB Carrier Detect Threshold DPSK or FSK receive data -49 -42 dBm0 Bell 103 8 20 ms Bell 212A 15 32 ms Bell 202 Forward Channel 6 12 ms Bell 202 Back Channel 25 40 ms Bell 103 6 20 ms Bell 212A 10 24 ms Bell 202 Forward Channel 3 8 ms Bell 202 Back Channel 10 25 ms Delay Time Hold Time Hysteresis 2 dB Special Tone Detectors Detect Level See definitions for TR bit D0 mode -49 -42 dBm0 10 25 ms 4 10 ms 202 Main Channel Mark 10 25 ms 202 Back Channel Mark 20 65 ms 1270 or 2225 Hz marks 10 25 ms Delay Time Answer tone 900 Hz SCT tone Preceded by valid carrier* * If SCT duration >4ms, it is guaranteed to detect. 19 73K302L Bell 212A, 103, 202 Single-Chip Modem DYNAMIC CHARACTERISTICS AND TIMING (continued) PARAMETER CONDITION MIN NOM MAX UNIT Special Tone Detectors (continued) Hold Time Answer tone 4 15 ms 900 Hz SCT tone 1 10 ms 202 Main Channel Mark 3 10 ms 202 Back Channel Mark 10 25 ms 1270 or 2225 Hz marks 5 15 ms Hysteresis Detect Freq. Range 2 Any Special Tone -3 TXA pin; FSK Single Tone out for THD = -50 dB in 0.3 to 3.4 kHz 10 dB +3 % Output Smoothing Filter Output Load kΩ 50 pF -60 dBm0 Out of Band Energy Frequency >12 kHz in all modes See Transmit Energy Spectrum Output Impedance TXA pin 20 50 Ω Clock Noise TXA pin; 76.8 kHz or 122.88 kHz in 202 main channel 0.1 0.4 mVrms +10 Hz 100 ms +625 ppm 50 ms Carrier VCO Capture Range Originate or Answer Capture Time -10 Hz to +10 Hz Carrier Frequency Change -10 40 DPSK Recovered Clock Capture Range % of data rate (center at 1200 Hz) Data Delay Time Analog data in at RXA pin to receive data valid at RXD pin -625 30 Tone Generator Tone Accuracy DTMF or FSK tones -5 +5 Hz Tone Level For DTMF, must not be in 202 mode -1 +1 dB 20 73K302L Bell 212A, 103, 202 Single-Chip Modem DYNAMIC CHARACTERISTICS AND TIMING PARALLEL CONTROL INTERFACE PARAMETER CONDITION MIN NOM MAX UNIT Timing (Refer to Timing Diagrams) * TAL CS/ADDr. setup before ALE Low 15 ns TLA CS/ADDr. hold after ALE Low 20 ns TLC ALE Low to RD/WR Low 30 ns TCL RD/WR Control to ALE High -5 ns TRD Data out from RD Low TLL ALE width TRDF Data float after RD High TRW RD width 200 ns TWW WR width 140 ns TDW Data setup before WR High 40 ns TWD Data hold after WR High 25 ns TWW WR width 140 TRD 140 30 ns ns 90 ns 25000 ns Data out from RD Low 140 ns TRDF Data float after RD High 50 ns TCKD Data out after EXCLK Low 200 ns TCKW WR after EXCLK Low 200 ns TDCK Write data setup before EXCLK Low 150 ns TAC Address setup before control* 50 ns TCA Address hold after control* 50 ns TWH Data hold after EXCLK 85 Control for setup is the falling edge of RD or WR. Control for hold is the falling edge of RD or the rising edge of WR. NOTE: Asserting ALE, CS, and RD or WR concurrently can cause unintentional register accesses. When using non-8031 compatible processors, care must be taken to prevent this from occurring when designing the interface logic. 21 73K302L Bell 212A, 103, 202 Single-Chip Modem TIMING DIAGRAMS BUS TIMING DIAGRAM (PARALLEL VERSION) TLL ALE TLC TRW TCL RD TLC TWW WR TLA TRD TRDF TWD TAL TDW ADDRESS AD0-AD7 READ DATA ADDRESS WRITE DATA CS READ TIMING DIAGRAM (SERIAL MODE) T1 T2 EXCLK TRCLK RD TAR A0-A2 TRA ADDRESS TRD D0 DATA TRDF TCKDR D1 D2 D3 D4 D5 D6 D7 WRITE TIMING DIAGRAM (SERIAL MODE) T2 EXCLK T1 TWW WR TCKW TAW A0-A2 ADDRESS TCKDW TDCK DATA D0 D1 D2 D3 D4 Note: EXCLK must be Low to read D0 after RD is asserted. 22 D5 D6 D7 TWA 73K302L Bell 212A, 103, 202 Single-Chip Modem APPLICATIONS INFORMATION interface. The parallel version is intended for use with 8039/48 or 8031/51 microcontrollers from Intel or many other manufacturers. The serial interface can be used with other microcontrollers or in applications where only a limited number of port lines are available or the application does not lend itself to a multiplexed address/data interface. The parallel versions may also be used in the serial mode, as explained in the data sheet pin description. GENERAL CONSIDERATIONS Figures 1 and 2 show basic circuit diagrams for K-Series modem integrated circuits. K-Series products are designed to be used in conjunction with a control processor, a UART or RS-232 serial data interface, and a DAA phone line interface to function as a typical intelligent modem. The K-Series ICs interface directly with Intel 8048 and 80C51 microprocessors for control and status monitoring purposes. Two typical DAA arrangements are shown: one for a split ±5 or ±12 volt design and one for a single 5V design. These diagrams are for reference only and do not represent productionready modem designs. In most applications the controller will monitor the serial data for commands from the DTE and the received data for break signals from the far end modem. In this way, commands to the modem are sent over the same line as the transmitted data. In other applications the RS-232 interface handshake lines are used for modem control. K-Series devices are available with two control interface versions: one for a parallel multiplexed address/data interface, and one for a serial C14 C13 39 pF N/C RS232 LEVEL CONVERTERS CA CB CC CD CF RTS CTS DSR DTR DCD XTL2 BA DB TXD RXD 18 pF +5V R10 2.2M XTL1 INT CLK XTL1 XTL2 INT ISET P0.0-7 P1.2 P1.3 RD WR RD WR ALE P1.5 P3.1 ALE CS P1.6 P3.2 GND VREF C8 22 µF C10 0.1 µF R4 20K - LM 1458 C6 0.1 µF LOW U1A FAMILY R7 43.2K TXA RXCLK TXCLK C7 R6 0.1 µF 20K RESET + R4 5.1K C2 300 pF RXA POWER C1 390 pF R5 37.4K C11 0.1 µF RXA K-SERIES EXCLK U5, U6 MC145406 + C9 0.1 µF VDD 80C51 P1.0 P1.1 P3.0 P1.7 RESET BB DA DD Y1 11.0592 MHZ C3 1000 pF R3 3.6K V+ LM 1458 U1B + +5V V– C12 1 µF T1 MIDCOM 671-8005 R1 - TXA T 475 1% D3, D4 4.7V ZENER C5 0.47 µF 250V C4 0.033 µF U2 4N35 VR1 MOV V250L20 D1 IN4004 +5V R8 22K K1 D2 IN914 R9 10K R Q1 2N2222A FIGURE 1: Basic Box Modem with Dual-Supply Hybrid 23 +5 22K 73K302L Bell 212A, 103, 202 Single-Chip Modem APPLICATIONS INFORMATION (continued) amplitude than data, these signals will clip if a single-ended drive approach is used. The bridged driver uses an extra op-amp (U1A) to invert the signal coming from the gain setting op-amp (U1B) before sending it to the other leg of the transformer. Each op-amp then supplies half the drive signal to the transformer. The receive amplifier (U1C) picks off its signal at the junction of the impedance matching resistor and the transformer. Because the bottom leg of the transformer is being driven in one direction by U1A and the resistor is driven in the opposite direction at the same time by U1B, the junction of the transformer and resistor remains relatively constant and the receive signal is unaffected. DIRECT ACCESS ARRANGEMENT (DAA) The telephone line interfaces show two examples of how the “hybrid” may be implemented. The split supply design (Figure 1) is a typical two op-amp hybrid. The receive op-amp serves two purposes. It supplies gain to amplify the receive signal to the proper level for the modem’s detectors and demodulator, and it removes the transmitted signal from the receive signal present at the transformer. This is done by supplying a portion of the transmitted signal to the non-inverting input of the receive op-amp at the same amplitude as the signal appearing at the transformer, making the transmit signal common mode. DESIGN CONSIDERATIONS The single-supply hybrid is more complex than the dual-supply version described above, but its use eliminates the need for a second power supply. This circuit (Figure 2) uses a bridged drive to allow undistorted signals to be sent with a single 5V supply. Because DTMF tones utilize a higher TDK Semiconductor's 1-chip modem products include all basic modem functions. This makes these devices adaptable for use in a variety of applications, and as easy to control as conventional digital bus peripherals. C1 390 pF R4 37.4K 1% C3 0.1 µF 8 RXA * U1C + C4 0.0047 µF R1 20K 1% 9 R2 20K 1% R5 3.3K +5V 5 6 4 + - 11 Note: Op-amp U1 must be rated for single 5V operation. R10 & R11 values depend on Op-amp 10 R3 475 1% 7 T1 MIDCOM 671-8005 * U1B C6 0.1 µF R7 20K 1% C2 0.033 µF C5 750 pF U2 4N35 TXA R9 20K 1% 3.3V ZENERS 2 3 - * U1A T R13 22K VR1 MOV V250L20 D1 IN4004 D2 R8 20K 1% +5V C10 0.47 µF 250V R6 22.1K R12 22K D3 1 + +5V +5V VOLTAGE REFERENCE K1 D4 IN914 R10* R R11* C7 0.1 µF + R14 10K Q1 2N2222A C8 10 µF HOOK RING FIGURE 2: Single 5V Hybrid Version 24 73K302L Bell 212A, 103, 202 Single-Chip Modem MODEM PERFORMANCE CHARACTERISTICS Unlike digital logic circuitry, modem designs must properly contend with precise frequency tolerances and very low level analog signals, to ensure acceptable performance. Using good analog circuit design practices will generally result in a sound design. Following are additional recommendations which should be taken into consideration when starting new designs. The curves presented here define modem IC performance under a variety of line conditions while inducing disturbances that are typical of those encountered during data transmission on public service telephone lines. Test data was taken using an AEA Electronics’ “Autotest I” modem test set and line simulator, operating under computer control. All tests were run full-duplex, using a Concord Data Systems 224 as the reference modem. A 511 pseudo-random-bit pattern was used for each data point. Noise was Cmessage weighted and all signal-to-noise (S/N) ratios reflect total power measurements similar to the CCITT V.56 measurement specification. The individual tests are defined as follows. CRYSTAL OSCILLATOR The K-Series crystal oscillator requires a parallel mode (antiresonant) crystal which operates at 11.0592 MHz. It is important that this frequency be maintained to within ±0.01% accuracy. In order for a parallel mode crystal to operate correctly and to specification, it must have a load capacitor connected to the junction of each of the crystal and internal inverter connections, terminated to ground. The values of these capacitors depend primarily on the crystal’s characteristics, and to a lesser degree on the internal inverter circuit. The values used affect the accuracy and start up characteristics of the oscillator. BER vs. S/N This test measures the ability of the modem to operate over noisy lines with a minimum of data-transfer errors. Since some noise is generated in the best of dial-up lines, the modem must operate with the lowest S/N ratio possible. Better modem performance is indicated by test curves that are closest to the BER axis. A narrow spread between curves representing the four line parameters indicates minimal variation in performance while operating over a range of aberrant operating conditions. Typically, a DPSK modem will exhibit better BER-performance test curves receiving in the low band than in the high band. LAYOUT CONSIDERATIONS Good analog/digital design rules must be used to control system noise in order to obtain highest performance in modem designs. The more digital circuitry present on the PC board, the more this attention to noise control is needed. The modem should be treated as a high impedance analog device. A 22 µF electrolytic capacitor in parallel with a 0.1 µF ceramic capacitor between VDD and GND is recommended. Liberal use of ground planes and larger traces on power and ground are also highly favored. High speed digital circuits tend to generate a significant amount of EMI (Electro-Magnetic Interference) which must be minimized in order to meet regulatory agency limitations. To accomplish this, high speed digital devices should be locally bypassed, and the telephone line interface and K-Series device should be located close to each other near the area of the board where the phone line connection is accessed. To avoid problems, power supply and ground traces should be routed separately to the analog and digital functions on the board, and digital signals should not be routed near low level or high impedance analog traces. The analog and digital grounds should only connect at one point near the K-Series device ground pin to avoid ground loops. The K-Series modem IC’s should have both high frequency and low frequency bypassing as close to the package as possible. BER vs. Receive Level This test measures the dynamic range of the modem. Because signal levels vary widely over dial-up lines, the widest possible dynamic range is desirable. The minimum Bell specification calls for 36 dB of dynamic range. S/N ratios are held constant at the indicated values while the receive level is lowered from a very high to very low signal levels. The width of the “bowl” of these curves, taken at the BER point, is the measure of dynamic range. . 25 73K302L Bell 212A, 103, 202 Single-Chip Modem 73K302L BER vs S/N 73K302L BER vs S/N 10-2 10-2 HIGH BAND RECEIVE -30 dBm DPSK OPERATION 1200 bit/s 10-3 10-3 BIT ERROR RATE BIT ERROR RATE C2 3002 W/O EQ. 10-4 FLAT W/EQ. C1 or 3002 FLAT 10-4 FLAT W/O EQ. C2 W/O EQ. 10-5 10-5 C2 W/EQ. RECEIVE LEVEL -30 dBm BELL 202 MODE 3002 W/EQ. 10-6 10-6 4 6 8 10 12 14 16 2 4 SIGNAL TO NOISE (dB) 6 8 10 14 73K302L BER vs PHASE JITTER 73K302L BER vs RECEIVE LEVEL 10-2 10-2 HIGH BAND RECEIVE DPSK OPERATION HIGH BAND RECEIVE DPSK OPERATION C2 LINE 10-3 BIT ERROR RATE 10-3 BIT ERROR RATE 12 SIGNAL TO NOISE (dB) 10-4 10-4 3002 11.5 dB S/N S/N = 10.8 dB 10-5 10-5 C2 10.8 dB S/N S/N = 15 dB 10-6 10-6 10 0 -10 -20 -30 -40 -50 0 RECEIVE LEVEL (dBm) 4 8 12 16 PHASE JITTER (DEG.) 26 20 24 73K302L Bell 212A, 103, 202 Single-Chip Modem 73K302L BER vs CARRIER OFFSET 10-2 HIGH BAND RECEIVE DPSK OPERATION BIT ERROR RATE 10-3 10-4 3002 11.8 dB S/N C2 11.3 dB S/N 10-5 10-6 12 8 4 0 -4 -8 -12 CARRIER OFFSET (HZ) 27 73K302L Bell 212A, 103, 202 Single-Chip Modem MECHANICAL SPECIFICATIONS 28-Pin DIP 28-Pin PLCC 0.495 (12.573) 0.075 (1.905) 0.485 (12.319) PIN NO. 1 IDENT. 0.065 (1.651) 0.165 (4.191) 0.180 (4.572) 0.495 (12.573) 0.456 (11.650) 0.485 (12.319) 0.450 (11.430) 0.050 (1.270) 0.045 (1.140) 0.016 (0.406) 0.020 (0.508) 0.390 (9.906) 0.430 (10.922) 0.456 (11.650) 0.450 (11.430) 28 0.020 (0.508) 73K302L Bell 212A, 103, 202 Single-Chip Modem PACKAGE PIN DESIGNATIONS CAUTION: Use handling procedures necessary for a static sensitive component. (Top View) CLK 1 28 GND XTL1 2 27 RXA XTL2 3 26 VREF AD0 4 25 RESET AD1 5 24 ISET AD2 6 23 RXCLK AD3 7 22 RXD AD4 8 21 TXD AD5 9 20 CS AD6 10 19 EXCLK AD7 11 18 TXCLK ALE 12 17 INT WR 13 16 TXA RD 14 15 VDD 4 3 2 1 28 27 26 5 25 6 24 7 8 9 PLCC PINOUTS ARE THE SAME AS THE 28-PIN DIP 23 22 21 10 20 11 19 12 13 14 15 16 17 18 600 Mil 28-Pin DIP 73K302L-28-IP 28-Pin PLCC 73K302L-IH ORDERING INFORMATION PART DESCRIPTION ORDER NUMBER PACKAGING MARK 73K302L 28-Pin Plastic Dual-In-Line 73K302L-IP 73K302L-IP 28-Pin Plastic Leaded Chip Carrier 73K302L-IH 73K302L-IH No responsibility is assumed by TDK Semiconductor Corporation for use of this product nor for any infringements of patents and trademarks or other rights of third parties resulting from its use. No license is granted under any patents, patent rights or trademarks of TDK Semiconductor Corporation and the company reserves the right to make changes in specifications at any time without notice. Accordingly, the reader is cautioned to verify that the data sheet is current before placing orders. TDK Semiconductor Corporation, 2642 Michelle Drive, Tustin, CA 92780-7019, (714) 508-8800, FAX: (714) 508-8877 Protected by the following patents: (4,777,453), (4,691,172 ã1990 TDK Semiconductor Corporation 04/24/00- rev. D 29