19-3818; Rev 0; 9/05 622Mbps/1244Mbps Burst-Mode Clock Phase Aligner for GPON OLT Applications The MAX3634 burst-mode clock phase aligner (CPA) is designed specifically for 622Mbps or 1244Mbps GPON (ITU G.984) optical line terminal (OLT) receiver applications. The MAX3634 provides clock and clock-aligned resynchronized upstream data through differential LVPECL outputs. Using the OLT system clock as a reference, the MAX3634 aligns to the input data and acquires within the first 13 bits of the burst. The CPA operates with received data that is frequency locked to the OLT reference. The acquisition time, bit-error ratio, and jitter tolerance all support GPON PMD specifications. LVPECL high-speed clock and data outputs provide compatibility with FPGAs at 622Mbps and with the MAX3885 deserializer at 1244Mbps. The MAX3634 is available in a low-profile, 7mm x 7mm, 48-lead TQFN package. The MAX3634 operates from a single +3.3V supply, over the -40°C to +85°C temperature range. Features ♦ DC-Coupled Clock Phase Aligner for Burst-Mode GPON Applications ♦ 13-Bit Burst Acquisition Time ♦ 0.85UI High-Frequency Jitter Tolerance ♦ Continuous Clock Output ♦ Byte Rate (1/8th Data Rate) Reference Clock Input ♦ Lock Detect Output ♦ LVPECL Serial Data Input and Output ♦ LVPECL Reset Input Ordering Information PART TEMP RANGE PINPACKAGE MAX3634ETM -40°C to +85°C 48 TQFN (7mm x 7mm) Applications 622Mbps GPON OLT Receivers PKG CODE T4877-6 1244Mbps GPON OLT Receivers Pin Configuration appears at end of data sheet. Typical Application Circuit BURST ENABLE BURST RESET DATA 4 MAX3634 CLOCK BURST-MODE CLOCK PHASE ALIGNER BURST-MODE TIA/LA UPSTREAM 1244Mbps MAX3656 MAX3892 BURST-MODE LASER DRIVER DATA SERIALIZER DATA CLOCK DIVIDE BY 16 DIVIDE BY 8 OLT CLOCK DATA RATESEL MAX3738 CONTINUOUS LASER DRIVER GPON OPTICAL LINE TERMINATION DOWNSTREAM 2488Mbps MAX3864 MAX3748A TIA/LA MAX3872 CLOCK SONET CDR DATA GPON OPTICAL NETWORK TERMINATION ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX3634 General Description MAX3634 622Mbps/1244Mbps Burst-Mode Clock Phase Aligner for GPON OLT Applications ABSOLUTE MAXIMUM RATINGS VCC, VCCI, VCCO, VCCV ........................................-0.5V to +4.0V SDI±, RST±, REFCLK±, RATESEL, FILT, TEST.............................-0.5V to (VCC + 0.5V) LVPECL Output Current (SDO±, SCLK±, LOCK±).............50mA Continuous Power Dissipation (TA = +85°C) 48-Lead TQFN package (derate 27.8mW/°C above +85°C) .............................1800mW Storage Temperature Range .............................-55°C to +150°C Operating Ambient Temperature Range .............-40°C to +85°C Lead Temperature (soldering, 10s) .................................+400°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VCC = +3.0V to +3.6V, TA = -40°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted.) PARAMETER Supply Current SYMBOL ICC Data Rate Reference Clock Input Frequency SDI, RST, REFCLK Differential Input CONDITIONS SDO±, SCLK±, LOCK± Output Voltage High mA 622.08 RATESEL = low 155.52 RATESEL = high 77.76 Mbps MHz 200 1600 mVP-P -180 +180 µA Rate = 1244Mbps 200 Rate = 622Mbps 200 VCC - 1.49 VCC - VIN/4 TA = 0°C to +85°C (Note 1) VCC - 1.81 VCC - 1.62 TA = -40°C to 0°C (Note 1) VCC - 1.83 VCC - 1.555 TA = 0°C to +85°C (Note 1) VCC - 1.025 VCC - 0.88 TA = -40°C to 0°C (Note 1) VCC - 1.085 VCC - 0.88 VOL ps V V V VOH Jitter Tolerance UNITS 390 RATESEL = high SDI±, RST±, REFCLK± CommonMode Input SDO±, SCLK±, LOCK± Output Voltage Low MAX 315 1244.16 VIN tr, tf TYP RATESEL = low SDI±, RST±, REFCLK± Input Current RST Input Rise/Fall Times MIN Not including LVPECL output current 622Mbps (Notes 2, 5, 6) 0.73 0.83 1244Mbps (Notes 2, 5, 6) 0.73 0.81 UIP-P Acquisition Time (Notes 2, 3) Bit-Error Ratio After acquisition (Notes 2, 4) 10-10 13 Bits SDO±, LOCK± Transition Time tr, tf 20% to 80% (Note 1) 265 ps SCLK± Transition Time tr, tf 20% to 80% (Note 1) 200 ps 2 _______________________________________________________________________________________ 622Mbps/1244Mbps Burst-Mode Clock Phase Aligner for GPON OLT Applications (VCC = +3.0V to +3.6V, TA = -40°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL Serial Data Output Clock-to-Q Delay (Figure 1) tCLK-Q Serial Data Output Q-to-Clock Delay (Figure 1) tQ-CLK RATESEL Input High VIH RATESEL Input Low VIL MIN 622Mbps (Notes 1, 2) 500 1244Mbps (Notes 1, 2) 250 622Mbps (Notes 1, 2) 500 1244Mbps (Notes 1, 2) 250 TYP MAX UNITS ps ps 2 RATESEL Input Current Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: CONDITIONS VIN = 0V or VCC V -100 0.8 V +100 µA PECL output must have external termination of 50Ω to VCC - 2V (Thevenin equivalent). AC parameters are guaranteed by design and characterization. From start of PON burst, 101010101010 preamble sequence. BER, acquisition time requirements are met with 100mVP-P sinusoidal noise on VCC, 0 < fNOISE ≤ 10MHz. Measured with 20psRMS input random jitter (1.244Mbps), 30psRMS (622Mbps) Jitter tolerance refers to the variation in phase between REFCLK and SDI after acquisition. (SCLK+) - (SCLK-) (SDO+) - (SDO-) tQ-CLK tCLK-Q Figure 1. Definition of Clock-to-Q and Q-to-Clock Delay Typical Operating Characteristics (VCC = +3.3V and TA = +25°C, unless otherwise noted) SDI BURST CAPTURE AT 1.244Gbps MAX3634 toc02 MAX3634 toc01 622Mbps INPUT AND OUTPUT EYE DIAGRAMS SDI MAX3634 toc03 1.244Gbps INPUT AND OUTPUT EYE DIAGRAMS RST SDI LOCK SDO SDO SDO 200ps/div 400ps/div 1ns/div _______________________________________________________________________________________ 3 MAX3634 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (VCC = +3.3V and TA = +25°C, unless otherwise noted) JITTER TOLERANCE vs. SDI-TO-REFCLK PHASE (1.244Gbps) JITTER TOLERANCE vs. SDI-TO-REFCLK PHASE (622Mbps) 0.7 LIMITED BY TEST EQUIPMENT 0.6 0.5 0.4 0.3 0.7 0.5 0.4 0.3 0.2 0.1 0.1 0 0 0 200 400 600 800 LIMITED BY TEST EQUIPMENT 0.6 MAX3634 toc06 0.8 0.2 340 320 SUPPLY CURRENT (mA) 0.8 0.9 JITTER TOLERANCE (UIP-P) 0.9 SUPPLY CURRENT vs. TEMPERATURE MAX3634 toc05 1.0 MAX3634 toc04 1.0 JITTER TOLERANCE (UIP-P) MAX3634 622Mbps/1244Mbps Burst-Mode Clock Phase Aligner for GPON OLT Applications 300 280 260 240 220 EXCLUDES PECL OUTPUT CURRENT 200 0 SDI-TO-REFCLK PHASE (ps) 200 400 600 800 -50 SDI-TO-REFCLK PHASE (ps) 0 50 100 AMBIENT TEMPERATURE (°C) Pin Description PIN NAME 1, 2, 12, 25, 36, 37, 48 GND Supply Ground 3, 6, 7, 10 VCCI +3.3V Supply for Input Buffers 4 SDI+ Positive Serial Data Input, LVPECL 5 SDI- Negative Serial Data Input, LVPECL 8 RST+ Positive Reset Input, LVPECL. Reset (= RST+ - RST-) is falling edge triggered. 9 RST- Negative Reset Input, LVPECL 11, 38, 39, 44, 47 VCC +3.3V Supply for Digital Circuitry 13–20, 22, 23 TEST Production Test Pins, Reserved. Leave open for normal operation. 21, 24, 26, 29, 32, 35 VCCO +3.3V Supply for Output Buffers 27 LOCK- Negative Lock Status Output, LVPECL LOCK+ Positive Lock Status Output, LVPECL. Lock (= (LOCK+) - (LOCK-)) high indicates that the MAX3634 has acquired the correct phase. 28 30 SDO- 31 SDO+ Positive Serial Data Output, LVPECL 33 SCLK- Negative Serial Clock Output, LVPECL 34 SCLK+ Positive Serial Clock Output, LVPECL 40 RATESEL 41, 43 VCCV +3.3V Supply for VCO 42 FILT PLL Filter Capacitor. Connect a 0.1µF X7R capacitor from pin 42 to VCCV. 45 REFCLK- Negative Reference Clock Input, LVPECL (1/8th data rate) 46 REFCLK+ Positive Reference Clock Input, LVPECL EP 4 FUNCTION Negative Serial Data Output, LVPECL Rate Select Input, TTL. High selects 622.08Mbps operation. Exposed Pad The exposed pad must be connected to the ground plane for proper thermal performance. _______________________________________________________________________________________ 622Mbps/1244Mbps Burst-Mode Clock Phase Aligner for GPON OLT Applications Theory of Operation The MAX3634 CPA provides serial clock and data outputs for GPON upstream bursts. The burst-mode CPA operates on the principle that the recovered clock from the ONT CDR is used at each ONT to clock upstream data bursts out of the ONT controller. The burst-mode CPA has logic that determines the correct phase relationship between the upstream data and the OLT reference clock at the beginning of each ONT’s burst, and resamples the upstream data at each bit using that clock. The burst-mode CPA contains a phase-locked loop (PLL) that synchronizes its oscillator to the reference clock input. This oscillator drives a phase splitter, which generates eight evenly spaced phases of the serial clock, which are used to sample the input data at 1/8th bit intervals in eight flip-flops. Combinatorial and sequential logic measures the preamble, and based on the phase of the preamble, determines which one of the eight clock phases is at the center of the input data bits. The data from the flip-flop associated with this phase is then steered through a multiplexer to the CPA output, which requires four or five additional clock periods until valid data is output. The CPA serial output clock is continuous, without any phase jumps or discontinuities from burst to burst. The burst-mode CPA requires a preamble sequence of 1010101010101 (13 bits) for correct phase alignment. Typically, output begins after the 12th bit, although for certain data/phase relationships, 13 bits are required. An LVPECL-compatible lock status output is provided, which indicates when the correct phase has been acquired and valid serial output data is available. This output remains low until reset by the burst reset input (RST). The output data is disabled (held low) during the period between reset and lock. Reference Clock Input The MAX3634 includes a PLL, which multiplies the reference clock by eight for use in the retiming circuitry. For correct operation, the REFCLK input must be connected to the OLT byte-rate reference clock, which must be equal to 1/8th the serial data rate, and must have a 40% to 60% duty cycle. This must be the same clock source used to time the downstream data, and the upstream data must be frequency locked to this source. The RATESEL input is used to configure 622Mbps or 1244Mbps operation; when RATESEL is high, the MAX3634 operates at 622Mbps. REFCLK+ LVPECL 622Mbps/1244Mbps PLL/PHASE SPLITTER φ0 RATESEL TTL MAX3634 BURST-MODE CPA φ7 D Q SDO+ MUX SDI+ SDI- LVPECL D D Q SYNCHRONIZER REFCLK- LVPECL SCLK+ LVPECL SCLK- Q RST+ RST- SDO- LOCK+ LVPECL PHASE-ACQUISITION LOGIC LVPECL LOCK- Figure 2. Functional Block Diagram _______________________________________________________________________________________ 5 MAX3634 General Description MAX3634 622Mbps/1244Mbps Burst-Mode Clock Phase Aligner for GPON OLT Applications Input Stage rest (BRST) signal. It then uses the next 8 bits of preamble (10101010) to measure the phase relationship between the reference clock and upstream data (after the internal logic has been reset), and 3 to 5 bits later begins outputting data. The time interval from BRST to the end of the preamble must be no less than 18 bits long. If the 8 bits of preamble that it uses to measure phase have been excessive pulse-width distortion, the phase measurement is in error. The LVPECL serial data input, SDI±, and burst-mode reset input, RST±, provide 200mVP-P sensitivity. The RST± input rise and fall times (20% to 80%) must not exceed 200ps. LVPECL inputs must be DC-coupled with external termination for correct operation with burst data (see Maxim Application Note HFAN 1.0 for termination configuration). Lock Detect The active edge of the reset input (BRST) must arrive at the MAX3634 after the TIA has finished its level recovery, but no sooner than 18 bits prior to the end of the (repeating 10 pattern) preamble, in order to provide adequate time for the MAX3634 to initialize, measure the phase, and load the output pipelines. This timing is shown in Figure 3. After the first 12 or 13 bits of the preamble, plus 4 or 5 bits of synchronizer delay, LOCK asserts to indicate the beginning of valid data output. Applications Information GPON Burst-Mode Timing Internally, the MAX3634 requires five internal clock cycles (8x REFCLK) to initialize itself after receiving the DATA INPUT TO MAX3634 TLR TDSR TCR RESET TDSR: BURST-TO-BURST SEPARATION TIME TLR: TIA/LA LEVEL RECOVERY TIME TCR: CPA RESET AND ACQUISITION TIME, ≥ 19 BITS DATA VALID GUARD TIME TIA/LA ACQUISITION CPA RESET (5 BITS) CPA ACQUISITION (12 OR 13 BITS) OUTPUT DATA VALID Figure 3. Clock Phase Aligner Operation Timing Diagram 6 _______________________________________________________________________________________ 622Mbps/1244Mbps Burst-Mode Clock Phase Aligner for GPON OLT Applications TRANSISTOR COUNT: 10,805 PROCESS: Silicon Germanium BiCMOS GND VCCO LOCK- LOCK+ VCCO SDO- SDO+ VCCO SCLK- SCLK+ VCCO GND Chip Information 36 35 34 33 32 31 30 29 28 27 26 25 GND 37 24 VCCO VCC 38 23 TEST10 VCC 39 22 TEST9 RATESEL 40 21 VCCO VCCV 41 20 TEST8 FILT 42 19 TEST7 MAX3634 VCCV 43 18 TEST6 VCC 44 17 TEST5 REFCLK- 45 16 TEST4 15 TEST3 REFCLK+ 46 EP* VCC 47 14 TEST2 13 TEST1 SDI+ SDI- 8 9 10 11 12 GND VCCI 7 VCC GND 6 VCCI 5 RST- 4 RST+ 3 VCCI 2 VCCI 1 GND GND 48 TQFN *EP MUST BE CONNECTED TO GROUND. _______________________________________________________________________________________ 7 MAX3634 Pin Configuration Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) E DETAIL A 32, 44, 48L QFN.EPS MAX3634 622Mbps/1244Mbps Burst-Mode Clock Phase Aligner for GPON OLT Applications (NE-1) X e E/2 k e D/2 CL (ND-1) X e D D2 D2/2 b L E2/2 e E2 CL L L1 CL k DETAIL B CL L L e A1 A2 e A PACKAGE OUTLINE 32, 44, 48, 56L THIN QFN, 7x7x0.8mm 21-0144 E 1 2 PACKAGE OUTLINE 32, 44, 48, 56L THIN QFN, 7x7x0.8mm 21-0144 E 2 2 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.