ACS8520 SETS Synchronous Equipment Timing Source for Stratum 3/4E/4 and SMC Systems ADVANCED COMMUNICATIONS Description FINAL Features The ACS8520 is a highly integrated, single-chip solution for the Synchronous Equipment Timing Source (SETS) function in a SONET or SDH Network Element. The device generates SONET or SDH Equipment Clocks (SEC) and Frame Synchronization clocks. The ACS8520 is fully compliant with the required international specifications and standards. The device supports Free-run, Locked and Holdover modes. It also supports all three types of reference clock source: recovered line clock, PDH network, and node synchronization. The ACS8520 generates independent SEC and BITS/SSU clocks, an 8 kHz Frame Synchronization clock and a 2 kHz Multi-Frame Synchronization clock. Two ACS8520 devices can be used together in a Master/ Slave configuration mode allowing system protection against a single ACS8520 failure. A microprocessor port is incorporated, providing access to the configuration and status registers for device setup and monitoring. The ACS8520 supports IEEE 1149.1 JTAG boundary scan. The user can choose between OCXO or TCXO to define the Stratum and/or Holdover performance required. PRODUCT BRIEF Suitable for Stratum 3, 4E, 4 and SONET Minimum Clock (SMC) or SONET/SDH Equipment Clock (SEC) applications Meets Telcordia 1244-CORE Stratum 3 and GR-253, and ITU-T G.813 Options Ι and ΙΙ specifications Accepts 14 individual input reference clocks, all with robust input clock source quality monitoring. Simultaneously generates nine output clocks, plus two Sync pulse outputs Absolute Holdover accuracy better than 3 x 10-10 (manual), 7.5 x 10-14 (instantaneous); Holdover stability defined by choice of external XO Programmable PLL bandwidth, for wander and jitter tracking/attenuation, 0.1 Hz to 70 Hz in 10 steps Automatic hit-less source switchover on loss of input Microprocessor interface - Intel, Motorola, Serial, Multiplexed, or boot from EPROM Output phase adjustment in 6 ps steps up to ±200 ns IEEE 1149.1 JTAG Boundary Scan Single 3.3 V operation. 5 V tolerant Available in LQFP 100 package Block Diagram Figure 1 Block Diagram of the ACS8520 SETS T4 DPLL/Freq. Synthesis 2 x AMI 10 x TTL 2 x PECL/LVDS Programmable; 64/8 kHz (AMI) 2 kHz 4 kHz N x 8 kHz 1.544/2.048 MHz 6.48 MHz 19.44 MHz 25.92 MHz 38.88 MHz 51.84 MHz 77.76 MHz 155.52 MHz TCK TDI TMS TRST TDO T4 Selector Optional Divider, 1/n n = 1 to 214 PFD Digital Loop Filter T4 APLL DTO Frequency Dividers Input Port Monitors and Selection Control T0 DPLL/Freq. Synthesis T0 APLL (output) 14 x SEC T0 Selector IEEE 1149.1 JTAG Chip Clock Generator Optional Divider, 1/n n = 1 to 214 PFD Priority Register Set Table Digital Loop Filter Microprocessor Port OCXO or TCXO Frequency Dividers DTO Output Ports TO1 to TO7 Outputs T01-TO7: E1/DS1 (2.048/ 1.544 MHz) and frequency multiples: 1.5 x, 2 x, 3 x 4 x, 6 x, 12 x 16 x and 24 x E3/DS3 2 kHz 8 kHz and OC-N* rates TO8 & TO9 T08: AMI TO9: E1/DS1 TO10 & TO11 TO10: 8 kHz (FrSync) TO11: 2 kHz (MFrSync) TO APLL (feedback) OC-N* rates = OC-1 51.84 MHz OC-3 155.52 MHz and derivatives: 6.48 MHz 19.44 MHz 25.92 MHz 38.88 MHz 51.84 MHz 77.76 MHz 155.52 MHz 311.04 MHz F8520P_001BLOCKDIA_03 Revision 2.00/October 2003 © Semtech Corp. Page 1 www.semtech.com ACS8520 SETS ADVANCED COMMUNICATIONS Pin Diagram FINAL Table 1 Power Pins (cont...) Figure 2 ACS8520 Pin Diagram SONSDHB MSTSLVB IC7 IC6 IC5 TO9 TO5 TO4 AGND3 VA3+ TO3 TO2 TO1 DGNDb VDDb VDDc DGNDc AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7 Pin No. 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 1 2 3 4 5 6 7 8 9 10 11 1 12 13 14 15 16 17 18 19 20 21 22 23 24 25 AGND TRST IC1 IC2 AGND1 VA1+ TMS INTREQ TCK REFCLK DGND1 VD1+ VD3+ DGND3 DGND2 VD2+ IC3 SRCSW VA2+ AGND2 TDO IC4 TDI I1 I2 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 ACS8520 SONET/SDH SETS RDY PORB ALE RDB WRB CSB A0 A1 A2 A3 A4 A5 A6 DGNDd VDDd UPSEL0 UPSEL1 UPSEL2 I14 I13 I12 I11 I10 I9 I8 I/O Type 11, 14, DGND1, 15, DGND3, DGND2, P - Supply Ground: Digital ground for components in PLLs. 49, 62, DGNDa, 84, 87 DGNDd, DGNDc, DGNDb P - Supply Ground: Digital ground for logic. 29 GND_AMI P - Supply Ground: Digital ground for AMI output. 32, 38 GND_DIFFa, GND_DIFFb P - Supply Ground: Digital ground for differential ports. 1, 5, 20, 92 AGND, AGND1, AGND2, AGND3 P - Supply Ground: Analog grounds. VAMI+ TO8NEG TO8POS GND_AMI FrSync MFrSync GND_DIFFa VDD_DIFFa TO6POS TO6NEG TO7POS TO7NEG GND_DIFFb VDD_DIFFb I5POS I5NEG I6POS I6NEG VDD5 SYNC2K I3 I4 I7 DGNDa VDDa 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Pin Description Pin No. I/O Type 12, 13, VD1+, 16 VD3+, VD2+ P - Supply Voltage: Digital supply to gates in analog section, +3.3 Volts ±10%. 26 VAMI+ P - Supply Voltage: Digital supply to AMI output, +3.3 Volts ±10%. 33, 39 VDD_DIFFa, VDD_DIFFb P - Supply Voltage: Digital supply for differential ports, +3.3 Volts ±10%. 44 VDD5 P - Digital Supply for +5 Volts Tolerance to Input Pins. Connect to +5 Volts (±10%) for clamping to +5 Volts. Connect to VDD for clamping to +3.3 Volts. Leave floating for no clamping, input pins tolerant up to +5.5 Volts. 50, 61, 85, 86 Symbol IC1, IC2, IC3, IC4, IC5, IC6, IC7 I/O Type - - Description Internally Connected: Leave to Float. Table 3 Other Pins Table 1 Power Pins Symbol Description Table 2 Internally Connected 3, 4, 17, 22, 96, 97, 98 F8520D_002PINDIAG_03 Symbol Note...I = Input, O = Output, P = Power, TTLU = TTL input with pull-up resistor, TTLD = TTL input with pull-down resistor. Pin No. Pin No. PRODUCT BRIEF - Description VDDa, VDDd, VDDc, VDDb P Supply Voltage: Digital supply to logic, +3.3 Volts ±10%. 6 VA1+ P - Supply Voltage: Analog supply to clock multiplying PLL, +3.3 Volts ±10%. 19, 91 VA2+, VA3+ P - Supply Voltage: Analog supply to output PLLs, +3.3 Volts ±10%. Revision 2.00/October 2003 © Semtech Corp. Symbol I/O Type Description 2 TRST I TTLD JTAG Control Reset Input: TRST = 1 to enable JTAG Boundary Scan mode. TRST = 0 for Boundary Scan stand-by mode, still allowing correct device operation. If not used connect to GND or leave floating. 7 TMS I TTLU JTAG Test Mode Select: Boundary Scan enable. Sampled on rising edge of TCK. If not used connect to VDD or leave floating. 8 INTREQ O TTL/CMOS 9 TCK I TTLD JTAG Clock: Boundary Scan clock input. If not used connect to GND or leave floating. 10 REFCLK I TTL Reference Clock: 12.800 MHz 18 SRCSW I TTLD Source Switching: Force Fast Source Switching. 21 TDO O TTL/CMOS JTAG Output: Serial test data output. Updated on falling edge of TCK. If not used leave floating. 23 TDI I TTLU JTAG Input: Serial test data Input. Sampled on rising edge of TCK. If not used connect to VDD or leave floating. Page 2 Interrupt Request: Active High/Low software Interrupt output. www.semtech.com ACS8520 SETS ADVANCED COMMUNICATIONS FINAL Table 3 Other Pins (cont...) Pin No. Symbol Table 3 Other Pins (cont...) I/O Type Description Pin No. 24 I1 I AMI Input Reference 1: Composite clock 64 kHz + 8 kHz. 25 I2 I AMI Input Reference 2: Composite clock 64 kHz + 8 kHz. 27 TO8NEG O AMI Output Reference 8: Composite clock, 64 kHz + 8 kHz negative pulse. 28 TO8POS O AMI Output Reference 8: Composite clock, 64 kHz + 8 kHz positive pulse. 30 FrSync O TTL/CMOS Output Reference 10: 8 kHz Frame Sync output. 31 MFrSync O TTL/CMOS Output Reference 11: 2 kHz Multi-Frame Sync output. 34, 35 TO6POS, TO6NEG O LVDS/PECL Output Reference 6: Programmable, default 38.88 MHz, default type LVDS. 36, 37 TO7POS, TO7NEG O PECL/LVDS Output Reference 7: Programmable, default 19.44 MHz, default type PECL. 40, 41 I5POS, I5NEG I LVDS/PECL Input Reference 5: Programmable, default 19.44 MHz, default type LVDS. 42, 43 I6POS, I6NEG I PECL/LVDS Input Reference 6: Programmable, default 19.44 MHz, default type PECL. 45 SYNC2K I TTLD External Sync input: 2 kHz, 4 kHz or 8 kHz for frame alignment. 46 I3 I TTLD Input Reference 3: Programmable, default 8 kHz. 47 I4 I TTLD Input Reference 4: Programmable, default 8 kHz. 48 I7 I TTLD Input Reference 7: Programmable, default 19.44 MHz. 51 I8 I TTLD Input Reference 8: Programmable, default 19.44 MHz. 52 I9 I TTLD Input Reference 9: Programmable, default 19.44 MHz. 53 I10 I TTLD Input Reference 10: Programmable, default 19.44 MHz. 54 I11 I TTLD Input Reference 11: Programmable, default (Master mode) 1.544/2.048 MHz, default (Slave mode) 6.48 MHz. 55 I12 I TTLD Input Reference 12: Programmable, default 1.544/2.048 MHz. 56 I13 I TTLD Input Reference 13: Programmable, default 1.544/2.048 MHz. 57 PRODUCT BRIEF I14 I TTLD Input Reference 14: Programmable, default 1.544/2.048 MHz. 58 - 60 UPSEL(2:0) I TTLD Microprocessor Select: Configures the interface for a particular microprocessor type at reset. Revision 2.00/October 2003 © Semtech Corp. I/O Type Description 63 - 69 A(6:0) I TTLD Microprocessor Interface Address: Address bus for the microprocessor interface registers. A(0) is SDI in Serial mode - output in EPROM mode only. 70 CSB I TTLU Chip Select (Active Low): This pin is asserted Low by the microprocessor to enable the microprocessor interface output in EPROM mode only. 71 WRB I TTLU Write (Active Low): This pin is asserted Low by the microprocessor to initiate a write cycle. In Motorola mode, WRB = 1 for Read. 72 RDB I TTLU Read (Active Low): This pin is asserted Low by the microprocessor to initiate a read cycle. 73 ALE I TTLD Address Latch Enable: This pin becomes the address latch enable from the microprocessor. When this pin transitions from High to Low, the address bus inputs are latched into the internal registers. ALE = SCLK in Serial mode. 74 PORB I TTLU Power-On Reset: Master reset. If PORB is forced Low, all internal states are reset back to default values. 75 RDY O TTL/CMOS Ready/Data Acknowledge: This pin is asserted High to indicate the device has completed a read or write operation. 76 - 83 AD(7:0) IO TTLD Address/Data: Multiplexed data/address bus depending on the microprocessor mode selection. AD(0) is SDO in Serial mode. 88 TO1 O TTL/CMOS Output Reference 1: Programmable, default 6.48 MHz. 89 TO2 O TTL/CMOS Output Reference 2: Programmable, default 38.88 MHz. 90 TO3 O TTL/CMOS Output Reference 3: Programmable, default 19.44 MHz. 93 TO4 O TTL/CMOS Output Reference 4: Programmable, default 38.88 MHz. 94 TO5 O TTL/CMOS Output Reference 5: Programmable, default 77.76 MHz. 95 TO9 O TTL/CMOS Output Reference 9: 1.544/2.048 MHz, as per ITU G.783 BITS requirements. 99 MSTSLVB I TTLU Master/Slave Select: Sets the state of the Master/Slave selection register, Reg. 34, Bit 1. 100 SONSDHB I TTLD SONET or SDH Frequency Select: Sets the initial power-up state (or state after a PORB) of the SONET/SDH frequency selection registers, Reg. 34, Bit 2 and Reg. 38, Bit 5, Bit 6 and Reg. 64 Bit 4. When set Low, SDH rates are selected (2.048 MHz etc.) and when set High, SONET rates are selected (1.544 MHz etc.) The register states can be changed after power-up by software. Page 3 Symbol www.semtech.com ACS8520 SETS ADVANCED COMMUNICATIONS Introduction FINAL General Description The ACS8520 SETS device is the industry standard singlechip solution for all of the SETS functions in both SONET and SDH Network Elements. It is a highly integrated and easily configurable device which generates and maintains accurate and stable SEC and Frame/Multi-Frame Synchronization pulse outputs, compliant with the required international telecom specifications and standards. The ACS8520 provides a simple, compact, highly flexible synchronization solution, which can be easily tailored for use with a range of transmission formats and rates, via software configuration. The ACS8520 employs various mechanisms to maintain the integrity of its output clocks when its input clocks fail or fall below the required specification levels. By smoothing out the effects of these input anomalies, the ACS8520 improves the overall stability and reliability of the downstream system synchronization, which translates to improved quality of service. In addition to the benefits of having all the SETS functionality on one chip, a key architectural advantage that the ACS8520 has over traditional solutions is in the use of Digital Phase Locked Loop (DPLL) technology for precise and repeatable performance over temperature or voltage variations and between parts. Semtech can provide an Evaluation Board and an intuitive, GUI-based Software package so that designers can rapidly appraise the ACS8520 SETS device and see for themselves the benefits that a Semtech SETS solution can bring to their designs. Figure 3 Evaluation Software Graphical User Interface PRODUCT BRIEF Inputs The ACS8520 SETS device accepts 14 input clocks via the input ports I1 to I12 (10 x TTL, 2 x PECL/LVDS, 2 x AMI). All the TTL/CMOS ports are 3 V and 5 V compatible (with clamping if required by connecting the VDD5 pin). The AMI inputs are typically ±1 V A.C. coupled. Input frequencies supported range from 2 kHz to 155.52 MHz. Common E1, DS1, OC-3 and sub-divisions are supported as spot frequencies to which the DPLLs will directly lock. Any input frequency, up to 100 MHz, that is a multiple of 8 kHz can also be locked to via a built-in programmable divider. The ACS8520 supports all three types of reference clock source: Recovered Line Clock, PDH Network Synchronization Timing and Node Synchronization. Refer to Table 4 for details of each input port. Monitors A monitoring function constantly appraises the frequency/activity of each input reference source, and reports anomalous behavior. Each of the 14 input monitors is individually configurable, allowing flags or interrupts to be raised which can influence both the operating state of the device and which inputs are available for selection by the PLL circuitry. Any reference source which suffers a loss-of-activity or clock-out-of-band condition will be declared as unavailable. Anomalies detected by the activity detector are integrated in a Leaky Bucket Accumulator. Occasional anomalies do not cause the Accumulator to cross the alarm setting threshold, so the selected reference source is retained. Persistent anomalies cause the alarm setting threshold to be crossed and result in the selected reference source being rejected. The ACS8520 performs frequency monitoring to identify reference sources which have drifted outside the acceptable frequency range measured with respect either to the output clock or to the XO clock. A soft alarm is raised if the drift is outside ±11.43 ppm and a hard alarm is raised if the drift is outside ±15.24 ppm. Revision 2.00/October 2003 © Semtech Corp. Page 4 www.semtech.com ACS8520 SETS ADVANCED COMMUNICATIONS FINAL PRODUCT BRIEF Table 4 Input Reference Source Selection and Priority Table Port Number Channel Number Input Port Technology Frequencies Supported Default Priority I1 0001 AMI 64/8 kHz (composite clock, 64 kHz + 8 kHz) Default (SONET): 64/8 kHz Default (SDH): 64/8 kHz 2 I2 0010 AMI 64/8 kHz (composite clock, 64 kHz + 8 kHz) Default (SONET): 64/8 kHz Default (SDH): 64/8 kHz 3 I3 0011 TTL/CMOS Up to 100 MHz (see Note (i)) Default (SONET): 8 kHz Default (SDH): 8 kHz 4 I4 0100 TTL/CMOS Up to 100 MHz (see Note (i)) Default (SONET): 8 kHz Default (SDH): 8 kHz 5 I5 0101 LVDS/PECL LVDS default Up to 155.52 MHz (see Note (ii)) Default (SONET): 19.44 MHz Default (SDH): 19.44 MHz 6 I6 0110 PECL/LVDS PECL default Up to 155.52 MHz (see Note (ii)) Default (SONET): 19.44 MHz Default (SDH): 19.44 MHz 7 I7 0111 TTL/CMOS Up to 100 MHz (see Note (i)) Default (SONET): 19.44 MHz Default (SDH): 19.44 MHz 8 I8 1000 TTL/CMOS Up to 100 MHz (see Note (i)) Default (SONET): 19.44 MHz Default (SDH): 19.44 MHz 9 I9 1001 TTL/CMOS Up to 100 MHz (see Note (i)) Default (SONET): 19.44 MHz Default (SDH): 19.44 MHz 10 I10 1010 TTL/CMOS Up to 100 MHz (see Note (i)) Default (SONET): 19.44 MHz Default (SDH): 19.44 MHz 11 I11 1011 TTL/CMOS Up to 100 MHz (see Note (i)) Default (Master) (SONET): 1.544 MHz Default (Master) (SDH): 2.048 MHz Default (Slave) 6.48 MHz 12/1 (Note (iii)) I12 1100 TTL/CMOS Up to 100 MHz (see Note (i)) Default (SONET): 1.544 MHz Default (SDH): 2.048 MHz 13 I13 1101 TTL/CMOS Up to 100 MHz (see Note (i)) Default (SONET): 1.544 MHz Default (SDH): 2.048 MHz 14 I14 1110 TTL/CMOS Up to 100 MHz (see Note (i)) Default (SONET): 1.544 MHz Default (SDH): 2.048 MHz 15 Notes: (i) TTL ports (compatible also with CMOS signals) support clock speeds up to 100 MHz, with the highest spot frequency being 77.76 MHz. The actual spot frequencies are: 2 kHz, 4 kHz, 8 kHz (and N x 8 kHz), 1.544 MHz (SONET)/2.048 MHz (SDH), 6.48 MHz, 19.44 MHz, 25.92 MHz, 38.88 MHz, 51.84 MHz, 77.76 MHz. SONET or SDH input rate is selected via Reg. 34 bit 2, ip_sonsdhb). (ii) PECL and LVDS ports support the spot clock frequencies listed above plus 155.52 MHz (and 311.04 MHz for TO6 only). (iii) Input port I11 is set at priority 12 on the Master SETS IC and priority 1 on the Slave SETS IC, as default on power up (or PORB). The default setup of Master or Slave I11 priority is determined by the MSTSLVB pin. PLL Paths There are two main paths through the device, T0 and T4; these names refer to the pair of PLLs (one digital, one analog) that process the selected inputs to synthesize the required output frequencies. The T0 and T4 paths are independent of each other in the default state, allowing two separate inputs to be in independent use in the device at the same time. However the interconnections between PLL blocks within and between these paths is highly configurable, via register control. Several different paths can be obtained to provide the output frequencies and jitter performance required. In many configurations the paths are combined so that only the T0, or only the T4 input can be used, not both at the same time. Phase and Frequency Detector (PFD), a Digital Loop filter, and a Digital Timed Oscillator (DTO); however the DPLL architecture in the T0 path is actually more complex than that of the T4 path and provides greater functionality. Both paths include an input selector, an optionally selected divider, a DPLL, a multiplying and filtering APLL and an output frequency divider. In each path the DPLLs are shown in the Block Diagram as comprising a generic Revision 2.00/October 2003 © Semtech Corp. Features of the T0 and T4 PLL Paths z Automatic source selection according to input priorities and quality level z Different quality levels (activity alarm thresholds) for each input z Variable bandwidth, lock range and damping factor z Direct PLL locking to common SONET/SDH input frequencies or any multiple of 8 kHz z Automatic mode switching between Free-run, Locked and Holdover states z Fast detection on input failure and entry into Holdover mode (holds at the last good frequency value) Page 5 www.semtech.com ACS8520 SETS ADVANCED COMMUNICATIONS FINAL z Frequency translation between input and output rates via direct digital synthesis z High accuracy digital architecture for stable PLL dynamics combined with an APLL for low jitter final output clocks z z z z z z z Frame Synchronization clock. Tables 5 and 6 summarize the output frequency/jitter options and technologies supported for each output port. Table 5 Output Port Frequencies and Technologies Port Name T0 Additional Features: z PRODUCT BRIEF Non-revertive mode Phase Build-out (PBO) on source switch (hit-less source switching) I/O phase offset control Greater programmable bandwidth from 0.1 Hz to 70 Hz in 10 steps (T4 path programmable bandwidth in 3 steps, 18, 35 and 70 Hz) Noise rejection on low frequency inputs Manual Holdover frequency control Controllable automatic Holdover frequency filtering Frame Sync pulse alignment Either the software or an internal state machine controls the operation of the DPLL in the T0 path. The state machine for the T4 path is very simple and cannot be manually/externally controlled, however the overall operation can be controlled by using manual reference source selection. The T4 path can be used to measure phase difference between two inputs. The T0 path DPLL always produces an output at 77.76 MHz to feed the APLL, regardless of the frequency selected at the output pins. The T4 path can be operated at a number of frequencies. This is to enable the generation of extra output frequencies, which cannot be easily related to 77.76 MHz. When the T4 path is selected to lock to the T0 path, the T4 DPLL locks to 8 kHz supplied from the T0 DPLL. This is because all of the frequencies of operation of the T4 path can be divided to 8 kHz and this ensures synchronization of all the frequencies (except 2 kHz) within the two paths. Output Port Technology T01 TTL/CMOS T02 TTL/CMOS T03 TTL/CMOS T04 TTL/CMOS T05 TTL/CMOS T06 LVDS/PECL (LVDS default) T07 PECL/LVDS (PECL default) T08 AMI Frequencies Supported See Table 6 64/8 kHz (composite clock, 64 kHz + 8 kHz), fixed frequency. T09 TTL/CMOS Either 1.544 MHz or 2.048 MHz. T010 TTL/CMOS FrSync, 8 kHz programmable pulse width and polarity, see Reg. 7C. T011 TTL/CMOS MFrSync, 2 kHz programmable pulse width and polarity, see Reg. 7C. Table 6 TO1 to TO7 Frequency/Jitter Options Frequency (MHz) 2 kHz Jitter Level (typ) rms (ps) 60 8 kHz pk-pk (ns) 0.6 60 0.6 1.536 (not TO4/TO5) 250 1.5 1.544 (not TO4/TO5) 150 1.0 2.048 220 1.2 2.0586667 150 1.0 2.316 (not TO4/TO5) 2.7306667 2.796 (not TO4/TO5) 110 0.75 220 1.2 110 1.0 3.088 110 0.75 3.728 110 1.0 4.096 via Digital1 (not TO7) or Digital2 (not TO6) 3800 13 4.296 (not TO4/TO5) 120 1.0 4.86 (not TO4/TO5) 60 0.6 5.728 120 1.0 6.144 250 1.5 6.176 150 1.0 6.48 60 0.6 8.192 220 1.2 Outputs 8.2346667 760 2.6 9.264 110 0.75 The PLLs work together to ensure a number of frequencies are simultaneously available for selection at the 11 output ports (8 x TTL, 2 x PECL/LVDS, 1 x AMI). 10.922667 250 1.6 11.184 110 1.0 12.288 250 1.5 12.352 110 0.75 16.384 220 1.2 16.46933 760 2.6 17.184 120 1.0 18.528 110 0.75 19.44 60 0.6 21.84533 250 1.6 22.368 110 1.0 The various configurations make the ACS8520 capable of generating a total of 55 possible output frequencies. The ACS8520 can be configured to support OC-N, E1/DS1, E3/DS3 and BITS outputs, together with an 8 kHz Frame Synchronization clock and a 2 kHz MultiRevision 2.00/October 2003 © Semtech Corp. Page 6 www.semtech.com ACS8520 SETS ADVANCED COMMUNICATIONS FINAL Table 6 TO1 to TO7 Frequency/Jitter Options (cont...) Frequency (MHz) Jitter Level (typ) rms (ps) pk-pk (ns) 24.576 250 1.5 24.704 110 0.75 25.92 60 0.6 32.768 220 1.2 34.368 120 1.0 37.056 110 0.75 38.88 60 0.6 44.736 110 1.0 49.152 (TO4/TO5 only) 250 1.5 49.152 (TO6/TO7 only) 900 4.5 49.408 (TO4/TO5 only) 150 1.0 49.408 (TO6/TO7 only) 760 2.6 60 0.6 65.536 (TO4/TO5 only) 220 1.2 65.536 (TO6/TO7 only) 120 1.0 51.84 68.736 120 1.0 74.112 (TO4/TO5 only) 110 0.75 74.112 (TO6/TO7 only) 110 0.75 60 0.6 77.76 89.472 (TO4/TO5 only) 110 1.0 98.304 (TO6 only) 900 4.5 98.816 (TO6 only) 760 2.6 131.072 (TO6 only) 250 1.6 137.472 (TO4/TO5 only) 120 1.0 148.224 (TO6 only) 110 0.75 155.52 311.04 (TO6 only) 60 0.6 60 0.6 match the last known good frequency of the last selected reference source. The device uses stored data, acquired when the input reference source was still valid, to control its output frequency. The ACS8520 provides several configurable modes for refining Holdover operation. Input Selection Priorities Each input reference can be programmed with a priority number (see Table 4) allowing references to be chosen according to the highest priority valid input. The two paths (T0 and T4) have their own separate priority settings so that the paths can operate independently. Both paths operate either automatic or external source selection. Table 4 gives details of the input reference ports. Specific frequencies and priorities are set by configuration. Automatic Selection Under normal operation, the input reference sources are selected automatically by an order of priority. But, for special circumstances such as chip or board testing, the selection may be forced by configuration. Modes of Operation The device has three principle modes of operation: Free-run, Locked, and Holdover. In Free-run mode, the ACS8520 is not synchronized to an input reference source. It generates a stable, low-noise clock signal derived from, and with the same frequency accuracy as, the external oscillator. The accuracy can be enhanced via software calibration to within ±0.0196229 ppm. In Locked mode, the ACS8520 selects the most appropriate input reference source from its 14 available inputs and generates a stable, low-noise clock signal locked to the selected reference. When the Locked mode is achieved, the output signal is phase locked to the selected input reference source. The selected input reference source is determined by the priority table. When the ACS8520 is in Locked mode, the output frequency and phase follows that of the selected input reference source. Automatic operation selects a reference source based on its predefined priority and its current availability. A table is maintained which lists all reference sources in the order of priority. This is initially defined by the default configuration and can be changed, via the microprocessor interface, by the Network Manager. In this way, when all the defined sources are active and valid, the source with the highest programmed priority is selected but, if this source fails, then the next-highest source is selected. Ultra Fast Switching Reference sources are monitored using a Leaky Bucket approach to allow source qualification criterion to be monitored. A reference source is normally disqualified after the Leaky Bucket monitor thresholds have been crossed. An option for a faster disqualification has been implemented so that a loss of activity of just a few reference clock cycles will raise an alarm and cause a reference switch. External Protection Switching In Holdover mode, the ACS8520 generates a stable, lownoise clock signal from the internal oscillator, adjusted to Revision 2.00/October 2003 © Semtech Corp. PRODUCT BRIEF External Switching mode, for fast switching between inputs I3 or I5 and I4 or I6, can also be triggered directly from a dedicated pin (SRCSW). Page 7 www.semtech.com ACS8520 SETS ADVANCED COMMUNICATIONS Performance FINAL PRODUCT BRIEF magnitude higher than the DPLL bandwidth. This ensures that the overall system performance still maintains the advantage of consistent behavior provided by the digital approach. Conformance In all modes of operation, the frequency accuracy, jitter and drift performance of the clocks meet the requirements of the following specifications: ITU-T: G.736, G.742, G783, G.812, G.813, G.822, G.823, G.824, G.825. Telcordia: GR-253-CORE, Issue 3; GR-499-CORE, Issue 2; GR-1244-CORE, Issue 2. ANSI: T1.101-1999. ETSI: ETS 300 462-3, ETS 300 462-5. Performance Benefits from DPLL/APLL Technology The use of Digital Phase Locked Loop technology ensures precise and repeatable performance over temperature or voltage variations, and between parts. The overall PLL bandwidth, loop damping, pull-in range and frequency accuracy are all determined by digital parameters that provide a consistent level of performance. An APLL takes the signal from the DPLL output and provides a lower jitter output. The APLL bandwidth is set four orders of The DPLLs are clocked by the external oscillator module (OCXO or XO) therefore the Free-run or Holdover frequency stability is only determined by the stability of the external oscillator module. This second key advantage confines all temperature critical components to one well defined and pre-calibrated module, whose performance can be chosen to match the application; for example, a TCXO for Stratum 3 applications. All performance parameters of the DPLLs are programmable without the need to understand detailed PLL equations. Bandwidth, damping factor and lock range, for example, can all be set directly. The PLL bandwidth can be set over a wide range, 0.1 Hz to 70 Hz in 10 steps, to cover all SONET/SDH clock synchronization applications. A high level of phase and frequency accuracy is made possible in the ACS8520 by an internal resolution of up to 54 bits and internal Holdover accuracy up to 7.5 x 10-14 (instantaneous). Typical Application Figure 4 Semtech’s Product Family Solution for a Typical SONET/SDH Architecture Multiple Line cards Line Card Recovered Clock Master Clock Master Sync Slave Clock Slave Sync Stand-by Clock Stand-by Sync Frame Sync Multi Frame Sync ACS8515 ACS8525 ACS8526 ACS8527 FRAMER E1/DS1 To/from SONET/SDH/PDH Network MPLL LINE CARD PROTECTION Low Jitter/Low Skew Clock ACS8942 Distribution ACS8943 Low Jitter up to 622 MHz Backplane SERDES Slave Sync Card Master Sync Card Input CLK Sources Config. Priorities mP/Serial Bus SSM Primary Ref. Input/ output RDATA TDATA TCLK ACS8510 ACS8520 ACS8522 ACS8530 Priorities TCLK RCLK Line I/F Unit SETS Output CLKs ACS8110 SSM HANDLER Clock Distribution SEC F8942_SetsLinecardGenApp_02 Revision 2.00/October 2003 © Semtech Corp. Page 8 www.semtech.com ACS8520 SETS ADVANCED COMMUNICATIONS Register Map FINAL PRODUCT BRIEF Table 7 Register Map Data Bit Address (hex) Default (hex) Register Name RO = Read Only R/W = Read/Write chip_id (RO) 7 (MSB) 6 5 4 3 2 1 00 48 Device part number [7:0] 8 least significant bits of the chip ID 01 21 Device part number [15:8] 8 most significant bits of the chip ID chip_revision (RO) 02 00 test_register1 (R/W) 03 14 phase_alarm disable_180 sts_interrupts (R/W) 05 FF I8 valid change I7 valid change 06 3F operating_ mode main_ref_ failed sts_current_DPLL_frequency, see OC/OD 07 00 sts_interrupts (R/W) 08 50 Sync_ip_alarm T4_status sts_operating (RO) 09 41 SYNC2K_ alarm sts_priority_table (RO) 0 (LSB) Chip revision number [7:0] resync_ analog Set to 0 8K edge polarity Set to zero Set to zero I6 valid change I5 valid change I4 valid change I3 valid change I2 valid change I1 valid change I14 valid change I13 valid change I12 valid change I11 valid change I10 valid change I9 valid change Bits [18:16] of current DPLL frequency T4_DPLL_lock T4_inputs_ failed TO_DPLL_freq _soft_alarm AMI2_Viol AMI2_LOS T4_DPLL_freq _soft_alarm AMI1_Viol T0_DPLL_operating_mode 0A 00 Highest priority validated source Currently selected source 0B 00 3rd highest priority validated source 2nd highest priority validated source sts_current_DPLL_frequency[7:0] 0C 00 Bits [7:0] of current DPLL frequency [15:8] 0D 00 Bits [15:8] of current DPLL frequency (RO) [18:16] 07 00 0E 00 0F 00 sts_sources_valid (RO) sts_reference_sources (RO) Status of inputs: Bits [18:16] of current DPLL frequency I8 I7 Out-of-band alarm (soft) Out-of-band alarm (hard) I6 I5 I4 I3 I2 I1 I14 I13 I12 I11 I10 I9 No activity alarm Phase lock alarm Out-of-band alarm (soft) Out-of band alarm (hard) No activity alarm Phase lock alarm Input pairs (1 & 2) 10 66 Status of I2 Input Status of I1 Input (3 & 4) 11 66 Status of I4 Input Status of I3 Input (5 & 6) 12 66 Status of I6 Input Status of I5 Input (7 & 8) 13 66 Status of I8 Input Status of I7 Input (9 & 10) 14 66 Status of I10 Input Status of I9 Input (11 & 12) 15 66 Status of I12 Input Status of I11 Input (13 & 14) 16 66 Status of I14 Input Status of I13 Input cnfg_ref_selection_priority (1 & 2) 18 32 programmed_priority I2 programmed_priority I1 (R/W) (3 & 4) 19 54 programmed_priority I4 programmed_priority I3 (5 & 6) 1A 76 programmed_priority I6 programmed_priority I5 (7 & 8) 1B 98 programmed_priority I8 programmed_priority I7 (9 & 10) 1C BA programmed_priority I10 programmed_priority I9 (11 & 12) 1D DC programmed_priority I12 programmed_priority I11 programmed_priority I14 programmed_priority I13 (13 & 14) 1E FE cnfg_ref_source_frequency_ _1 20 00 Set to zero bucket_id_1 (R/W) _2 21 00 Set to zero bucket_id_2 Set to zero 3 22 00 divn_3 lock8k_3 bucket_id_3 reference_source_frequency_3 4 23 00 divn_4 lock8k_4 bucket_id_4 reference_source_frequency_4 5 24 03 divn_5 lock8k_5 bucket_id_5 reference_source_frequency_5 6 25 03 divn_6 lock8k_6 bucket_id_6 reference_source_frequency_6 7 26 03 divn_7 lock8k_7 bucket_id_7 reference_source_frequency_7 8 27 03 divn_8 lock8k_8 bucket_id_8 reference_source_frequency_8 9 28 03 divn_9 lock8k_9 bucket_id_9 reference_source_frequency_9 10 29 03 divn_10 lock8k_10 bucket_id_10 reference_source_frequency_10 Set to zero 11 2A 03 divn_11 lock8k_11 bucket_id_11 reference_source_frequency_11 12 2B 01 divn_12 lock8k_12 bucket_id_12 reference_source_frequency_12 13 2C 01 divn_13 lock8k_13 bucket_id_13 reference_source_frequency_13 14 2D 01 divn_14 lock8k_14 bucket_id_14 reference_source_frequency_14 cnfg_sts_remote_sources_valid (R/W) 30 FF 31 3F cnfg_operating_mode (R/W) 32 00 AMI1_LOS Revision 2.00/October 2003 © Semtech Corp. Remote status, channels <8:1> Remote status, channels <14:9> TO_DPLL_operating_mode Page 9 www.semtech.com ACS8520 SETS ADVANCED COMMUNICATIONS FINAL PRODUCT BRIEF Table 7 Register Map (cont...) Address (hex) Default (hex) Register Name RO = Read Only R/W = Read/Write Data Bit 7 (MSB) 6 force_select_reference_source (R/W) 33 0F cnfg_input_mode (Bit 1 RO, otherwise R/W) 34 C2 auto_extsync_ en phalarm_ timeout cnfg_T4_path (R/W) 35 40 lock_T4_to_T0 T4_dig_ feedback cnfg_differential_inputs (R/W) 36 02 cnfg_uPsel_pins (RO) 37 02 5 4 3 2 XO_ edge man_holdover extsync_en I6_PECL 1F 39 08 cnfg_differential_outputs (R/W) 3A C6 cnfg_auto_bw_sel (R/W) 3B FB [7:0] 3C 99 Nominal frequency [7:0] [15:8] 3D 99 Nominal frequency [15:8] (R/W) dig2_sonsdh digital2_frequency T07_PECL_LVDS auto_BW_sel T06_LVDS_PECL T0_lim_int 00 Holdover frequency [7:0] 00 Holdover frequency [15:8] 88 I5_LVDS digital1_frequency [7:0] 3E 40 reversion_ mode dig1_sonsdh [15:8] 3F cnfg_holdover_modes (R/W) master_slaveb Microprocessor type 38 cnfg_holdover_frequency 0 (LSB) T4_forced_reference_source cnfg_dig_outputs_sonsdh (R/W) (R/W) ip_sonsdhb T4_op_ from_T0 cnfg_digtial_frequencies (R/W) cnfg_nominal_frequency 1 forced_reference_source auto_ averaging fast_averaging read_average mini_holdover_mode Holdover frequency [18:16] (with Registers 3E and 3F above) cnfg_DPLL_freq_limit (R/W) [7:0] 41 76 [9:8] 42 00 cnfg_interrupt_mask (R/W) [7:0] 43 00 I8 interrupt not masked I7 interrupt not masked I6 interrupt not masked I5 interrupt not masked I4 interrupt not masked I3 interrupt not masked I2 interrupt not masked I1 interrupt not masked [15:8] 44 00 Operating_ mode interrupt not masked Main_ref_ failed interrupt not masked I14 interrupt not masked I13 interrupt not masked I12 interrupt not masked I11 interrupt not masked I10 interrupt not masked I9 interrupt not masked [23:16] 45 00 Sync_ip_ T4_status alarm interrupt interrupt not not masked masked T4_inputs_ failed interrupt not masked AMI2_Viol interrupt not masked AMI2_LOS interrupt not masked AMI1_Viol interrupt not masked AMI1_LOS interrupt not masked freq_monitor_ soft_enable freq_monitor_ hard_enable cnfg_freq_divn (R/W) DPLL frequency offset limit [7:0] DPLL frequency offset limit [9:8] [7:0] 46 FF [13:8] 47 3F divn_value [7:0] cnfg_monitors (R/W) 48 05 cnfg_freq_mon_threshold (R/W) 49 23 soft_frequency_alarm_threshold [3:0] hard_frequency_alarm_threshold [3:0] cnfg_current_freq_mon_ threshold (R/W) 4A 23 current_soft_frequency_alarm_threshold [3:0] current_hard_frequency_alarm_threshold [3:0] cnfg_registers_source_select (R/W) 4B 00 sts_freq_measurement (R/W) 4C 00 cnfg_DPLL_soft_limit (R/W) 4D 8E cnfg_upper_threshold_0 (R/W) 50 06 Configuration 0: Activity alarm set threshold [7:0] cnfg_lower_threshold_0 (R/W) 51 04 Configuration 0: Activity alarm reset threshold [7:0] cnfg_bucket_size_0 (R/W) 52 08 Configuration 0: Activity alarm bucket size [7:0] cnfg_decay_rate_0 (R/W) 53 01 cnfg_upper_threshold_1 (R/W) 54 06 Configuration 1: Activity alarm set threshold [7:0] divn_value [13:8] freq_mon_clk los_flag_ on_ TDO ultra_fast_ switch ext_switch T4_T0_select PBO_freeze PBO_en frequency_measurement_channel_select [3:0] freq_measurement_value [7:0] Freq limit Phase loss enable DPLL Frequency Soft Alarm Limit [6:0] Resolution = 0.628 ppm Cfg 0:decay_rate [1:0] cnfg_lower_threshold_1 (R/W) 55 04 Configuration 1: Activity alarm reset threshold [7:0] cnfg_bucket_size_1 (R/W) 56 08 Configuration 1: Activity alarm bucket size [7:0] cnfg_decay_rate_1 (R/W) 57 01 cnfg_upper_threshold_2 (R/W) 58 06 Configuration 2: Activity alarm set threshold [7:0] Cfg 1:decay_rate [1:0] cnfg_lower_threshold_2 (R/W) 59 04 Configuration 2: Activity alarm reset threshold [7:0] cnfg_bucket_size_2 (R/W) 5A 08 Configuration 2: Activity alarm bucket size [7:0] cnfg_decay_rate_2 (R/W) 5B 01 cnfg_upper_threshold_3 (R/W) 5C 06 cnfg_lower_threshold_3 (R/W) 5D 04 cnfg_bucket_size_3 (R/W) 5E 08 cnfg_decay_rate_3 (R/W) 5F 01 Revision 2.00/October 2003 © Semtech Corp. Cfg 2:decay_rate [1:0] Configuration 3: Activity alarm set threshold [7:0] Configuration 3: Activity alarm reset threshold [7:0] Configuration 3: Activity alarm bucket size [7:0] Cfg 3:decay_rate [1:0] Page 10 www.semtech.com ACS8520 SETS ADVANCED COMMUNICATIONS FINAL PRODUCT BRIEF Table 7 Register Map (cont...) Address (hex) Default (hex) Register Name RO = Read Only R/W = Read/Write Data Bit 7 (MSB) 6 5 4 3 2 1 0 (LSB) cnfg_output_frequency (R/W) (TO1 & TO2) 60 85 output_freq_2 (TO2) output_freq_1 (TO1) (TO3 & TO4) 61 86 output_freq_4 (TO4) output_freq_3 (TO3) (TO5 & TO6) 62 8A output_freq_6 (TO6) (TO7 to TO11) 63 F6 cnfg_T4_DPLL_frequency (R/W) 64 01 cnfg_T0_DPLL_frequency (R/W) 65 01 cnfg_T4_DPLL_bw (R/W) 66 00 cnfg_T0_DPLL_locked_bw (R/W) 67 0B MFrSync enable T4 for measuring T0 phase output_freq_5 (TO5) FrSync enable TO9 enable TO8 enable Auto Disable T4 output AMI Duty cycle T4 SONET/SDH selection T4 APLL for T0 E1/DS1 output_freq_7 <TO7> T4_DPLL_frequency T0_DPLL_frequency T0 Freq to T4 APLL T4_DPLL_bandwidth [1:0] T0_DPLL_locked_bandwidth [4:0] cnfg_T0_DPLL_acq_bw (R/W) 69 0F cnfg_T4_DPLL_damping (R/W) 6A 13 T4_PD2_gain_alog_8K [6:4] cnfg_T0_DPLL_damping (R/W) 6B 13 T0_PD2_gain_alog_8K [6:4] T0_damping [2:0] cnfg_T4_DPLL_PD2_gain (R/W) 6C C2 T4_PD2_gain_ enable T4_PD2_gain_alog [6:4] T4_PD2_gain_digital [2:0] cnfg_T0_DPLL_PD2_gain (R/W) 6D C2 T0_PD2_gain_ enable T0_PD2_gain_alog [6:4] T0_PD2_gain_digital [2:0] cnfg_phase_offset (R/W) T0_DPLL_acquisition_bandwidth [4:0] [7:0] 70 00 phase_offset_value[7:0] [15:8] 71 00 phase_offset_value[15:8] cnfg_PBO_phase_offset (R/W) PBO_phase_offset [5:0] 72 00 cnfg_phase_loss_fine_limit (R/W) 73 A2 Fine limit Phase loss enable (1) No activity for phase loss Test bit Set to 1 cnfg_phase_loss_coarse_limit (R/W) 74 85 Coarse limit Phase loss enable (2) Wide range enable Enable Multi Phase resp. cnfg_phasemon (R/W) 76 06 Input noise window enable sts_current_phase (RO) T4_damping [2:0] phase_loss_fine_limit [2:0] Phase loss coarse limit in UI pk-pk [3:0] [7:0] 77 00 current_phase[7:0] [15:8] 78 00 current_phase[15:8] Timeout value in 2s intervals [5:0] cnfg_phase_alarm_timeout (RO) 79 32 cnfg_sync_pulses (R/W) 7A 00 2 k/8 k out from T4 cnfg_sync_phase (R/W) 7B 00 indep_FrSync/ MFrSync cnfg_sync_monitor (R/W) 7C 2B ph_offset_ ramp cnfg_interrupt (R/W) 7D 02 cnfg_protection(R/W) 7E 85 cnfg_uPsel (R/W) 7F 02 * Revision 2.00/October 2003 © Semtech Corp. 8 k invert 8 k pulse enable 2 k invert 2 k pulse enable Sync_phase Sync_OC-N_ rates Sync_monitor_limit Sync_reference_source GPO interrupt enable Interrupt tristate enable Interrupt polarity enable protection_value Microprocessor type (*Default value depends on value on UPSEL[2:0] pins) Page 11 www.semtech.com ACS8520 SETS ADVANCED COMMUNICATIONS Ordering Information FINAL PRODUCT BRIEF Table 8 Parts List Part Number Description ACS8520 SETS Synchronous Equipment Timing Source for Stratum 3/4E/4 and SMC Systems ACS8520 EVB Evaluation Board and Software Disclaimers Life support- This product is not designed or intended for use in life support equipment, devices or systems, or other critical applications. This product is not authorized or warranted by Semtech for such use. Right to change- Semtech Corporation reserves the right to make changes, without notice, to this product. Customers are advised to obtain the latest version of the relevant information before placing orders. Compliance to relevant standards- Operation of this device is subject to the User’s implementation and design practices. It is the responsibility of the User to ensure equipment using this device is compliant to any relevant standards. Contacts For Additional Information, contact the following: Semtech Corporation Advanced Communications Products E-mail: [email protected] Internet: http://www.semtech.com USA: Mailing Address: Street Address: Tel: +1 805 498 2111, [email protected] P.O. Box 6097, Camarillo, CA 93011-6097 200 Flynn Road, Camarillo, CA 93012-8790 Fax: +1 805 498 3804 FAR EAST: 11F, No. 46, Lane 11, Kuang Fu North Road, Taipei, R.O.C. Tel: +886 2 2748 3380 Fax: +886 2 2748 3390 EUROPE: Semtech Ltd., Units 2 and 3, Park Court, Premier Way, Abbey Park Industrial Estate, Romsey, Hampshire, SO51 9DN Tel: +44 (0)1794 527 600 Fax: +44 (0)1794 527 601 ISO9001 CERTIFIED Revision 2.00/October 2003 © Semtech Corp. Page 12 www.semtech.com