TP3406 DASL Digital Adapter for Subscriber Loops General Description Features The TP3406 is a complete monolithic transceiver for data transmission on twisted pair subscriber loops. It is built on National’s double poly microCMOS process, and requires only a single a 5 Volt supply. Alternate Mark Inversion (AMI) line coding, in which binary ‘1’s are alternately transmitted as a positive pulse then a negative pulse, is used to ensure low error rates in the presence of noise with lower emi radiation than other codes such as Bi-phase (Manchester). Full-duplex transmission at 144 kb/s is achieved on a single twisted wire pair using a burst-mode technique (Time Compression Multiplexed). Thus the device operates as an ISDN ‘U’ Interface for short loop applications, typically in a PBX environment, providing transmission for 2 B channels and 1 D channel. On Ý24 cable, the range is up to 800 meters. System timing is based on a Master/Slave configuration, with the line card end being the Master which controls loop timing and synchronisation. All timing sequences necessary for loop activation and de-activation are generated on-chip. Selection of Master and Slave mode operation is programmed via the Microwire Control Interface. A 2.048 MHz clock, which may be synchronized to the system clock, controls all transmission-related timing functions. Complete ISDN PBX 2-Wire Data Transceiver including: Y 2 B plus D channel interface for PBX UÊ Interface Y 144 kb/s full-duplex on 1 twisted pair using Burst Mode Y Loop range up to 800 meters (Ý24AWG) Y Alternate Mark Inversion coding with transmit filter and scrambler for low emi radiation Y Adaptive line equalizer Y On-chip timing recovery, no external components Y Standard TDM interface for B channels Y Separate interface for D channel Y 2.048 MHz master clock Y Driver for line transformer Y 4 loop-back test modes Y Single a 5V supply Y MICROWIRE TM compatible serial control interface Y Applications in: PBX Line Cards Terminals Regenerators Y Available in 28-pin PLCC Package Block Diagram TL/H/11725 – 1 TRI-STATEÉ is a registered trademark of National Semiconductor Corporation MICROWIRETM is a trademark of National Semiconductor Corporation. C1995 National Semiconductor Corporation TL/H/11725 RRD-B30M115/Printed in U. S. A. TP3406 DASL Digital Adapter for Subscriber Loops November 1992 Connection Diagram TP3406 Package Information TL/H/11725 – 2 Order Number TP3406V See NS Package Number V28A Pin Descriptions Name GND Description Negative power supply pin, normally 0V. All analog and digital signals are referred to this pin. VCC Positive power supply input, which must be a 5V g 5%. The 2.048 MHz Master Clock input, which requires a CMOS logic level clock input from a stable source. Must be synchronous with BCLK. This pin is the 2.048 MHz Master Clock input, which requires either a crystal to be connected between this pin and XTAL2 or a CMOS logic level clock from a stable source, which must be synchronous with BCLK. This pin is the output side of the oscillator amplifier. MCLK MCLK/XTAL XTAL2 MBS/FSC BCLK FSa Name FSb Bx In Master Mode, this pin is the Master Burst Sync input, which may be clocked at 4 kHz to synchronize Transmit bursts from a number of devices at the Master end only. The 4 kHz should be nominally a square wave signal. If not used leave this pin open. In Slave mode, this pin is a short Frame Sync output, suitable for driving another DASL in Master Mode to provide a regenerator (i.e. range-extender) capability. Bit Clock logic signal which determines the data shift rate for B channel data on the digital interface side of the device. In Master mode this pin is an input which may be any multiple of 8 kHz from 256 kHz to 2.048 MHz, but must be synchronous with MCLK. In Slave mode this pin is an output at 2.048 MHz. Br Digital output for B1 and B2 channel data received from the line. TSr/LSD In Master mode only, this pin is an opendrain output which is normally high impedance but pulls low during both B channel active receive time slots. In Slave mode only, this pin is an output which is normally high impedance and pulls low when a valid line signal is received. Dx Digital input for D channel data to be transmitted to the line; must be synchronous with DCLK. Dr Digital output for D channel data received from the line. Dr is a TRI-STATE output. In Master mode this pin is an input for the 16 kHz serial shift clock for D channel data on Dx and Dr, which should be synchronous with BCLK. It may also be re-configured via the Control Register to act as an enable input for clocking the D channel interface synchronized to BCLK. In Slave mode this is a 16 kHz clock output for D channel data. DCLK/DEN In Master mode only, this pin is the Transmit Frame Sync pulse input, requiring a positive edge to indicate the start of the active channel time for transmit B channel data into Bx; FSa must be synchronous with BCLK and MCLK. In Slave mode only, this pin is a digi- Description tal output pulse which indicates the 8-bit periods of the B1 channel data transfer at both Bx and Br. In Master mode only, this pin is the Receive Frame Sync pulse input, requiring a positive edge to indicate the start of the active channel time of the device for receive B channel data out from Br; FSb must be synchronous with BCLK and MCLK. In Slave mode only, this pin is a digital output pulse which indicates the 8-bit periods of the B2 channel data transfer at both Bx and Br. Digital input for B1 and B2 channel data to be transmitted to the line; must be synchronous with BCLK. *Crystal specifications: 2.048 MHz parallel resonant, RS s 100X with a 20 pF load. Crystal tolerance should be g 75 ppm for aging and temperature. 2 LINE TRANSMIT SECTION Pin Descriptions (Continued) Name CI CO CCLK MICROWIRE control channel serial data input. MICROWIRE control channel serial data output. Clock input for the MICROWIRE control channel. CS Chip Select input which enables the MICROWIRE control channel data to be shifted in and out when pulled low. When high, this pin inhibits the MICROWIRE interface. INT Interrupt output, a latched output signal which is normally high-impedance and goes low to indicate a change of status of the loop transmission system. This latch is cleared when the Status Register is read by the microprocessor. Lo Transmit AMI signal output to the line transformer. This pin is capable of driving a load impedance t 60X. Receive AMI signal input from the line transformer. This is a high impedance input. Li Alternate Mark Inversion (AMI) line coding is used on the DASL because of its spectral efficiency and null dc energy content. All transmitted bits, excluding the start bit, are scrambled by a 9-bit scrambler to provide good spectral spreading with a strong timing content. The scrambler feedback polynomial is: x9 a x5 a 1. Description Pulse shaping is obtained by means of a raised cosine switched-capacitor filter, in order to limit rf energy and crosstalk while minimizing inter-symbol interference (isi). Figure 3 shows the pulse shape at the Lo output, while a template for the typical power spectrum transmitted to the line with random data is shown in Figure 4 . The line-driver output, Lo, is designed to drive a transformer through a capacitor and termination resistor. A 1:1 transformer, terminated in 100X, results in a signal amplitude of typically 1.3V pk-pk on the line. Over-voltage protection must be included in the interface circuit. LINE RECEIVE SECTION The front-end of the receive section consists of a continuous anti-alias filter followed by a switched-capacitor lowpass filter designed to limit the noise bandwidth with minimum intersymbol interference. To correct pulse attenuation and distortion caused by the transmission line an AGC circuit and first-order equalizer adapt to the received pulse shape, thus restoring a ‘‘flat’’ channel response with maximum received eye opening over a wide spread of cable attenuation characteristics. From the equalized output a DPLL (Digital Phase-Locked Loop) recovers a low-jitter clock for optimum sampling of the received symbols. The MCLK input provides the reference clock for the DPLL at 2.048 MHz. At the Master end of the loop this reference is the network clock (BCLK), which controls all transmit functions; the DPLL clock is used only for received data sampling. At the Slave end, however, a 2.048 MHz crystal is required to generate a stable local oscillator which is used as a reference by the DPLL to run both the receive and transmit sides of the DASL device. Following detection of the recovered symbols, the received data is de-scrambled by the same x9 a x5 a 1 polynomial and presented to the digital system interface circuit. When the device is de-activated, a Line-Signal Detect circuit remains powered-up to detect the presence of incoming bursts if the far-end starts to activate the loop. From a ‘‘cold’’ start, acquisition of bit timing and equalizer convergence with random scrambled data takes approximately 25 ms at each end of the loop. Full loop burst synchronization is achieved approximately 50 ms after the ‘‘activate’’ command at the originating end. Functional Description POWER-UP/POWER-DOWN CONTROL Following the initial application of power, the DASL enters the power-down (de-activated) state, in which all the internal circuits are inactive and in a low power state except for the line-signal detect circuit and the necessary bias circuit; the line output Lo is in a low impedance state and all digital outputs are inactive. All bits in the Control Register powerup initially set to ‘0’, so that the device always initializes as the Master end. Thus, at the Slave end, a control word must be written through the MICROWIRE port to select Slave mode. While powered-down, the Line-Signal Detect circuits in both Master and Slave devices continually monitor the line, to enable loop transmission to be initiated from either end. To power-up the device and initiate activation, bit C6 in the Control Register must be set high. Setting C6 low de-activates the loop and powers-down the device, see Table I. TABLE I. Master Mode Burst Sync Control (TP3401 Only) MBS/FSc Pin I/P at Master C6 State Don’t Care 0 Pull up this pin to a 5V through a resistor 4 kHz 1 1 Action Powered-down, Line-Signal Detect active Powered-up, sending bursts synchronized to FSa Powered-up, sending bursts synchronized to MBS 3 Functional Description (Continued) TL/H/11725 – 3 FIGURE 3. Typical AMI Waveform at Lo TL/H/11725 – 4 FIGURE 4. Typical AMI Transmit Spectrum Measured at LO Output (With RBW e 100 Hz). TL/H/11725 – 5 FIGURE 5. Burst Mode Timing on the Line 4 Functional Description (Continued) flexibility. On the B channel interface, phase skew between transmit and receive directions may be accommodated at the Master end since separate frame sync inputs, Fsa and Fsb, are provided. Each of these synchronizes a counter which gates the transfer of B1 and B2 channels in consecutive time-slots across the digital interface; since the counters are edge-synchronized the duration of the Fs input signals may vary from a single-bit pulse to a square-wave. The serial shift rate is determined by the BCLK input, and may be any frequency from 256 kHz to 2.048 MHz, as shown in Figure 6. At the Slave end, both Fsa and Fsb are outputs. Fsa goes high for 8 cycles of BCLK coincident with the 8 bits of the B1 channel in both Transmit and Receive directions. Fsb goes high for the next 8 cycles of BCLK, which are coincident with the 8 bits of the B2 channel in both Transmit and Receive directions. BCLK is also an output at 2.048 MHz, the serial data shift rate, as shown in Figure 7. Data may be exchanged between the B1 and B2 channels as it passes through the device, by setting Control bit C0 e 1. An additional Frame Sync output, FSc, is provided to enable a regenerator to be built by connecting a DASL in Slave Mode to a DASL in Master Mode. The FSc output from the Slave directly drives the FSa and FSb inputs on the Master. D channel information, being packet-mode, requires no synchronizing input. This interface consists of the transmit data input, Dx, receive data output, Dr, and 16 kHz serial shift clock DCLK, which is an input at the Master end and an output at the Slave end. Data shifts into Dx on falling edges of DCLK and out from Dr on rising edges, as shown in Figure 11. DCLK should be Synchronous with BCLK. An alternative function of the DCLK/DEN pin allows Dx and Dr to be clocked at the same rate as BCLK at the Master end only. By setting bit C1 in the Control Register to a 1, DCLK/DEN becomes an input for an enabling pulse to gate 2 cycles of BCLK for shifting the 2 D bits per frame. Thus, at the Master end, the D channel bits can be interfaced to a TDM bus and assigned to a time-slot (the same time-slot for both transmit and receive), as shown in Figure 12. BURST MODE OPERATION For full-duplex operation over a single twisted-pair, burst mode timing is used, with the line-card (exchange) end of the link acting as the timing Master. Each burst from the Master consists of the B1, B2 and D channel data from 2 consecutive frames combined in the format shown in Figure 5 . During transmit bursts the Master’s receiver input is inhibited to avoid disturbing the adaptive circuits. The Slave’s receiver is enabled at this time and it synchronizes to the start bit of the burst, which is always an unscrambled ‘1’ (of the opposite polarity to the last ‘1’ sent in the previous burst). When the Slave detects that 36 bits following the start bit have been received, it disables the receiver input, waits 6 line symbol periods to match the other end settling guard time, and then begins to transmit its burst back towards the Master, which by this time has enabled its receiver input. The burst repetition rate is thus 4 kHz, which can either free-run or be locked to a synchronizing signal at the Master end by means of the MBS input (See Figure 10 ). In the latter case, with all Master-end transmitters in a system synchronized together, near-end crosstalk between pairs in the same cable binder may be eliminated, with a consequent increase in signal-to-noise ratio (SNR). ACTIVATION AND LOOP SYNCHRONIZATION Activation (i.e. power-up and loop synchronization) is typically completed in 50 ms and may be initiated from either end of the loop. If the Master is activating the loop, it sends normal bursts of scrambled ‘1’s, which are detected by the Slave’s line-signal detect circuit, causing it to set C0 e 1 in the Status Register, and pull the INT pin low. Pin 6, the LSD pin, also pulls low. To proceed with Activation, the device must be powered up by writing to the Control Register with C6 e 1. The Slave then replies with bursts of scrambled ‘1’s synchronized to received bursts, and the flywheel circuit at each end searches for 4 consecutive correctly formatted receive bursts to acquire full loop synchronization. Each receiver indicates when it is correctly in sync with received bursts by setting the C1 bit in the Status Register high and pulling INT low. To activate the loop from the Slave end, bit C6 in the Control Register must be set high, which will power-up the device and begin transmission of alternate bursts i.e., the burst repetition rate is 2 kHz, not 4 kHz. At this point the Slave is running from its local oscillator and is not receiving any sync information from the Master. When the Master’s line-signal detect circuit recognizes this ‘‘wake-up’’ signal, the Master is activated and begins to transmit bursts, synchronized, as normal, to the MBS or FSa input with a 4 kHz repetition rate. This enables the Slave’s receiver to correctly identify burst timing from the Master and to re-synchronize its own burst transmissions to those it receives. The flywheel circuits then acquire full loop sync as described earlier. Loop synchronization is considered to be lost if the flywheel finds 4 consecutive receive burst ‘‘windows’’ (i.e. where a receive burst should have arrived based on timing from previous bursts) do not contain valid bursts. At this point bit C1 in the Status Register is set low, the INT output is set low and the receiver searches to re-acquire loop sync. CONTROL INTERFACE A serial interface, which can be clocked independently from the B and D channel system interfaces, is provided for microprocessor control of various functions on the DASL device. All data transfers consist of a single byte shifted into the Control Register via CI simultaneous with a single byte shifted out from the Status Register via CO, see Figure 13 . Data shifts in to CI on rising edges of CCLK and out from CO on falling edges when CS is pulled low for 8 cycles of CCLK. An Interrupt output, INT goes low to alert the microprocessor whenever a change in one of the status bits, C1 and/or C0 has occurred. This latched output is cleared high following the first CCLK pulse when CS is low. No interrupt is generated when status bit C2 (bipolar violation) goes high, however. This bit is set whenever 1 or more violations of the AMI coding rule is received, and cleared everytime the CS is pulsed. Statistics on the line bit error rate can be accumulated by regularly polling this bit. When reading the CO pin, data is always clocked into the Control Register; therefore the CI data word should repeat the previous instruction if no change to the device mode is intended. DIGITAL SYSTEM INTERFACE The digital system interface on the DASL separates B and D channel information onto different pins to provide maximum Figure 13 shows the timing for this interface, and Table II lists the control functions and status indicators. 5 Functional Description (Continued) TABLE II. Control and Status Register Functions Bit C7 C6 C5 C4 C3 C2 C1 C0 State 0 Control Register Function Status Register Function Master Mode Read Back C7 from Control Register 1 Slave Mode Read Back C7 from Control Register 0 Deactivate and Power Down Read Back C6 from Control Register 1 Power Up and Activate Read Back C6 from Control Register 0 Normal Through Connection Read Back C5 from Control Register 1 Loopback to Digital Interface Read Back C5 from Control Register 0 Normal Through Connection Read Back C4 from Control Register 1 Loopback B1 a B2 a D to Line (Note 1) Read Back C4 from Control Register 0 Normal Through Connection Read Back C3 from Control Register 1 Loopback B1 Only to Line (Note 1) Read Back C3 from Control Register 0 Normal Through Connection No Error 1 Loopback B2 Only to Line (Note 1) Bipolar Violation Since Last READ (Note 2) 0 DCLK/DEN pin e 16 kHz Clock Out-Of-Sync 1 DCLK/DEN pin e D Channel Enable (Note 3) Loop In-Sync and Activation Complete 0 B1/B2 Channels Direct No Line Signal at Receiver Input 1 B1/B2 Channels Exchanged Line Signal Present at Receiver Input Note 1: Receive data active. Note 2: After the device is in sync. Note 3: In Master mode only. Note 4: C7 is the first bit clocked in and out of the device. Timing Diagrams TL/H/11725 – 6 FIGURE 6. B Channel Interface Timing: Master Mode 6 Timing Diagrams (Continued) TL/H/11725 – 7 FIGURE 7. B Channel Interface Timing: Slave Mode Typical Applications TL/H/11725 – 8 FIGURE 8. Typical Application for Slave End Note 1: The TP3076 Programmable Combos also must be connected to the MICROWIRE interface. Note 2: Only necessary if a mechanical Hookswitch is connected to the NMI input of the HPC. Note 3: Crystal load capacitors include board and trace capacitance. Oscillator frequency can be checked by measuring the BCLK output frequency when slave mode part is in digital loopback. 7 Typical Applications (Continued) TL/H/11725 – 9 FIGURE 9. Typical Application for Master End Timing Diagrams (Continued) TL/H/11725 – 10 FIGURE 10. B Channel Interface Timing Details 8 Timing Diagrams (Continued) TL/H/11725 – 11 TL/H/11725 – 12 FIGURE 11. D Channel Interface Timing (Master and Slave Modes, C1 e 0) TL/H/11725 – 13 FIGURE 12. D Channel Interface Timing (Master Mode only, C1 e 1) 9 FIGURE 13. Control Interface Timing TL/H/11725 – 14 Timing Diagrams (Continued) 10 Absolute Maximum Ratings Storage Temperature Range If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. VCC to GND Voltage at Li, Lo Voltage at any Digital Input b 65§ C to a 150§ C Current at Lo g 100 mA Current at any Digital Output Lead Temperature (Soldering, 10 sec.) ESD (Human Body Model) 7V VCC a 1V to VSSb1V VCC a 1V to VSSb1V g 50 mA 300§ C 2000V Electrical Characteristics Unless otherwise noted, limits printed in bold characters are guaranteed for VCC e 5.0V g 5% and TA e 0§ C to a 70§ C by correlation with 100% electrical testing at VCC e 5.0V and TA e 25§ C. All other limits are assured by correlation with other production tests and/or product design and characterization. Typical characteristics are specified at VCC e 5.0V and TA e 25§ C. All digital signals are referenced to GND. Symbol Parameter Conditions Min Typ Max Units DIGITAL INTERFACES VIL Input Low Voltage All Digital Inputs (not MCLK) VIH Input High Voltage All Digital Inputs (not MCLK) VOL Output Low Voltage IL e 1 mA VOH Output High Voltage IL e b1 mA IIM Input Current at MBS/FSc GND k VIN k VCC II Input Current IOZ Output Current in High Impedance State (TRI-STATEÉ) 0.7 2.2 V V 0.4 V b 600 10 mA Any Other Digital Input, GND k VIN k VCC b 10 10 mA Br, INT, TSr, CO, Dr GND k VOUT k VCC b 10 10 mA 2.4 V LINE INTERFACES RLi Input Resistance 0V k Li k 5.0V CLLo Load Capacitance CLLo from Lo to GND. 50 RO Output Resistance at Lo Load e 60X in Series with 2 mF to GND VDC Mean d.c. Voltage at Lo Load e 60X in Series with 2 mF to GND kX 100 pF 3.0 X 2.0 V POWER DISSIPATION ICC0 Power Down Current ICC1 Power Up Current (Activated) 1.3 Load at Lo e 200X in Series with 2 mF to GND (in Master Mode) 2.5 mA 20 mA TRANSMISSION PERFORMANCE Transmit Pulse Amplitude at Lo RL e 200X in Series with 2 mF to GND Input Pulse Amplitude at Li Timing Recovery Jitter g 1.1 g 250 BCLK at Slave Relative to MCLK at Master 11 Vpk mVpk 100 ns pk-pk Timing Characteristics Unless otherwise noted: VCC e a 5V g 5%, TA e 0§ C to 70§ C. Typical characteristics are specified at VCC e 5V, TA e 25§ C. All signals are referenced to GND. Symbol Parameter Conditions Min Typ Max Units MASTER CLOCK INPUT SPECIFICATIONS FMCK Master Clock Frequency 2.048 Master Clock Tolerance Measured Relative to the Slave MCLK Master Clock Input Jitter 2.048 MHz Input, 18 kHz k f k 200 kHz tWMH, tWML Clock Pulse Width Hi & Low for MCLK VIH e VCC b 0.5V VIL e 0.5V tMR, tMF Rise and Fall Time of MCLK Used as a Logic Input b 100 MHz a 100 ppm 200 ns pk-pk 190 ns 15 ns B CHANNEL INTERFACE (Figure 10) FBCK Bit Clock Frequency Master Mode Only tWBH, tWBL Clock Pulse Width Hi & Low for BCLK VIH e 2.2V VIL e 0.7V 2.048 MHz tBR, tBF Rise and Fall Time of BCLK Master Mode requirement for BCLK Source tSFB Set-Up Time, FSa and FSb to BCLK Low Master Mode Only tHCFL Hold Time, BCLK Low to FSa and FSb Low Master Mode Only tWBH tWBL Output Pulse Width High and Low for BCLK Slave Mode Only Load e 2 LSTTL Inputs Plus 50 pF tDCF Delay Time, BCLK High to FSa, FSb and FSc Transitions Slave Mode Only Load e 2 LSTTL Inputs Plus 50 pF tSBC Set Up Time, BX Valid to BCLK Low 30 ns tHCB Hold Time, BCLK Low to BX Invalid 50 ns tDCB Delay Time, BCLK High to Br Valid Load e 2 LSTTL Inputs Plus 100 pF tDCBZ Delay Time, BCLK Low to Br High-Impedance Slave Mode Only tDCT Delay Time, BCLK High to TSr Low Load e 2 LSTTL Inputs Plus 100 pF tDCTZ Delay Time, BCLK Low to TSr High-Impedance tSMBC Set-Up Time, MBS to BCLK Low (Note 1) Master Mode Only tWMBH Width of MBS Input High Master Mode Only 190 ns 15 70 ns 100 ns 195 ns 115 60 60 Note 1: MBS transitions may occur anywhere in the Frame, and require no specific relationship to FSa or FSb. 12 ns 60 ns 160 ns 220 ns 180 ns 185 ns ns 125 ms Timing Characteristics (Continued) Unless otherwise noted: VCC e a 5V g 5%, TA e 0§ C to 70§ C. Typical characteristics are specified at VCC e 5V, TA e 25§ C. All signals are referenced to GND. Symbol Parameter Conditions Min Max Units D CHANNEL INTERFACE (Figure 11 & 12) tSDDC Set Up Time, DX Valid to DCLK Low 100 ns tHCD Hold Time, DCLK Low to DX Invalid 100 ns tDDCD Delay Time, DCLK High to Dr Data Valid Load e 100 pF a 2 LSTTL Inputs tSDCB Set-Up Time, DCLK Transitions to BCLK High Master Mode Only 50 ns tHBDC Hold Time, BCLK High to DCLK Transitions Master Mode Only 50 ns tSDCF Set-Up Time, DCLK Transitions to FSa HIgh Master Mode Only 70 ns tDDED Delay Time, DEN High to Dr Valid Load e 100 pF a 2 LSTTL Inputs tSDEB Set-Up Time, DEN to BCLK Low tSDBC 220 200 ns ns 100 ns Set-Up Time, Dx to BCLK Low 50 ns tHBCD Hold Time, BCLK Low to Dx Invalid 50 ns tDBCD Delay Time, BCLK High to Dr Valid tDCDZ Delay Time, DEN Low to Dr High Impedance Load e 100 pF a 2 LSSTL Inputs 190 ns 140 ns CONTROL INTERFACE (Figure 13) tCH CCLK High Duration 250 ns tCL CCLK Low Duration 250 ns tSIC Setup Time, CI Valid to CCLK High 100 ns tHCI Hold Time, CCLK High to CI Invalid 0 ns tSSC Setup Time from CS Low to CCLK High 200 ns tHCS Hold Time from CCLK Low to CS 10 ns tDCO Delay Time from CCLK Low to C0 Data Valid Load e 100 pF a 2 LSTTL Inputs tDSO Delay Time from CS Low to CO Valid 1st Bit Only tDSZ tDCI 150 ns 100 ns Delay Time from CS High to CO High Impedance 100 ns Delay Time from CCLK1 High to INT High Impedance 120 ns 13 Definitions and Timing Conventions DEFINITIONS VIH VIL VIH is the d.c. input level above which an input level is guaranteed to appear as a logical one. This parameter is to be measured by performing a functional test at reduced clock speeds and nominal timing, (i.e. not minimum setup and hold times or output strobes), with the high level of all driving signals set to VIH and maximum supply voltages applied to the device. VIL is the d.c. input level below which an input level is guaranteed to appear as a logical zero to the device. This parameter is measured in the same manner as VIH but with all driving signal low levels set to VIL and minimum supply voltages applied to the device. VOH VOH is the minimum d.c. output level to which an output placed in a logical one state will converge when loaded at the maximum specified load current. VOL VOL is the maximum d.c. output level to which an output placed in a logical zero state will converge when loaded at the maximum specified load current. Threshold Region The threshold region is the range of input voltages between VIL and VIH. Valid Signal A signal is Valid if it is in one of the valid logic states, (i.e. above VIH or below VIL). In timing specifications, a signal is deemed valid at the instant it enters a valid state. Invalid Signal A signal is Invalid if it is not in a valid logic state, i.e. when it is in the threshold region between VIL and VIH. In timing specifications, a signal is deemed invalid at the instant it enters the threshold region. TIMING CONVENTIONS For the purpose of this timing specification the following conventions apply: Input Signals All input signals may be characterized as: VL e 0.4V, VIH e 2.4V, tR k 10 ns, tF k 10 ns. Period The period of clock signal is designated at tPxx where xx represents the mnemonic of the clock signal being specified. 14 Rise Time Rise times are designated at tRyy, where yy represents a mnemonic of the signal whose rise time is being specified. tRyy is measured from VIL to VIH. Fall Time Fall times are designated as tFyy, where yy represents a mnemonic of the signal whose fall time is being specified. tFyy is measured from VIH to VIL. Pulse Width High The high width is designated as tWzzH, where zz represents the mnemonic of the input or output signal whose pulse width is being specified. High pulse widths are measured from VIH to VIH. Pulse Width Low The low pulse width is designed as tWzzL, where zz represents the mnemonic of the input or output signal whose pulse width is being specified. Low pulse widths are measured from VIL to VIL. Setup Time Setup times are designated as tSwwxx, where ww represents the mnemonic of the input signal whose setup time is being specified relative to a clock or strobe input represented by mnemonic xx. Setup times are measured from the ww Valid to xx Invalid. Hold Time Hold times are designated as tHxxww, where ww represents the mnemonic of the input signal whose hold time is being specified relative to a clock or strobe input represented by mnemonic xx. Hold times are measured from xx Valid to ww invalid. Delay Time Delay times are designated as tDxxyy [ lHlL], where xx represents the mnemonic of the input reference signal and yy represents the mnemonic of the output signal whose timing is being specified relative to xx. The mnemonic may optionally be terminated by an H or L to specifiy the high going or low going transition of the output signal. Maximum delay times are measured from xx Valid to yy Valid. Minimum delay times are measured from xx Valid to yy invalid. This parameter is tested under the load conditions specified in the Conditions column of the Timing Specification section of this data sheet. 15 TP3406 DASL Digital Adapter for Subscriber Loops Physical Dimensions inches (millimeters) Plastic Chip Carrier (V) Order Number TP3406V NS Package Number V28A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. 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 for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. National Semiconductor Corporation 1111 West Bardin Road Arlington, TX 76017 Tel: 1(800) 272-9959 Fax: 1(800) 737-7018 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. National Semiconductor Europe Fax: (a49) 0-180-530 85 86 Email: cnjwge @ tevm2.nsc.com Deutsch Tel: (a49) 0-180-530 85 85 English Tel: (a49) 0-180-532 78 32 Fran3ais Tel: (a49) 0-180-532 93 58 Italiano Tel: (a49) 0-180-534 16 80 National Semiconductor Hong Kong Ltd. 13th Floor, Straight Block, Ocean Centre, 5 Canton Rd. Tsimshatsui, Kowloon Hong Kong Tel: (852) 2737-1600 Fax: (852) 2736-9960 National Semiconductor Japan Ltd. Tel: 81-043-299-2309 Fax: 81-043-299-2408 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.