LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 LMK01801 Dual Clock Divider Buffer Check for Samples: LMK01801 1 Device Summary 1.1 Features 12 • Pin Control Mode or MICROWIRE (SPI) • Input and Output Frequency Range 1 kHz to 3.1 GHz • Separate Input for Clock Output Banks A & B. • 14 Differential Clock Outputs in Two Banks (A & B) – Output Bank A • 8 Differential, Programmable Outputs (Up to 8 as LVCMOS) • Divider Values of 1 to 8, Even and Odd. – Output Bank B 1.2 • • • • • • • • • • • • 6 Differential Outputs (or up to 12 as LVCMOS) • Divides Values of 1 to 1045 or 1 to 8, Even and Odd • Analog and Digital Delays 50% Duty Cycle on All Outputs for All Divides Separate Synchronization of Bank A and B. RMS Additive Jitter 50 fs at 800 MHz – 50 fs RMS Additive Jitter (12 kHz to 20 MHz) Industrial Temperature Range: -40 to 85 °C 3.15 V to 3.45 V Operation Target Applications High Performance Clock Distribution and Division Wireless Infrastructure Datacom and Telecom Clock Distribution Medical Imaging Test and Measurement Military / Aerospace 1.3 Description The LMK01801 is a very low noise solution for clocking systems that require distribution and frequency division of precision clocks. The LMK01801 features extremely low residual noise, frequency division, digital and analog delay adjustments, and fourteen (14) programmable differential outputs: LVPECL, LVDS and LVCMOS (2 outputs per differential output). The LMK01801 features two independent inputs that can be driven differentially (LVDS, LVPECL) or in single-ended mode (LVCMOS, RF Sinewave). The first input drives output Bank A consisting of eight (8) outputs. The second input drives output Bank B consisting of six (6) outputs. 1 2 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2012–2013, Texas Instruments Incorporated LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 1.4 www.ti.com Functional Block Diagram CLKin1 CLKin1* CLKin0 CLKin0* Bank B Bank A Divider (2-8) CG4 Divider Divider (1-8) LVDS/ LVPECL CLKout2 CLKout2* CLKout3 CLKout3* LVDS/ LVPECL/ LVCMOS CLKout4 CLKout4* CLKout5 CLKout5* LVDS/ LVPECL/ LVCMOS CLKout6 CLKout6* CLKout7 CLKout7* Clock Distribution Path B CG1 Divider Clock Distribution Path A CLKout0 CLKout0* CLKout1 CLKout1* Mux Mux LVDS/ LVPECL CLKin1 Divider CLKin0 Divider Divider (2-8) Digital Delay Divider (1-1045) Analog Delay Mux CLKout13 CLKout13* LVDS/ LVPECL/ LVCMOS Mux CLKout12 CLKout12* LVDS/ LVPECL/ LVCMOS CLKout11 CLKout11* CLKout10 CLKout10* LVDS/ LVPECL/ LVCMOS CLKout9 CLKout9* CLKout8 CLKout8* LVDS/ LVPECL/ LVCMOS CG3 Divider Divider (1-8) CG2 Divider Divider (1-8) SYNC0/ CLKoutTYPE_1 SYNC1/ CLKoutTYPE_2 Test/ CLKoutTYPE_0 CLKuWire/ CLKoutDIV_1 Device Control DATAuWire/ CLKoutDIV_0 PWire Port Control Registers LEuWire/ CLKoutDIV_2 EN_PIN_CTRL 2 Device Summary Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com 1 ........................................ 1 ............................................. 1 1.2 Target Applications .................................. 1 1.3 Description ........................................... 1 1.4 Functional Block Diagram ........................... 2 Device Information ...................................... 4 2.1 Functional Configurations ............................ 4 2.2 Connection Diagram ................................. 5 Electrical Specifications ............................... 7 3.1 Absolute Maximum Ratings .......................... 7 3.2 Package Thermal Resistance ....................... 7 3.3 Recommended Operating Conditions ............... 7 3.4 Electrical Characteristics ............................ 8 3.5 Serial MICROWIRE Timing Diagram ............... 11 Typical Performance Characteristics ............. 12 Measurement Definitions ............................ 13 Device Summary 1.1 2 3 4 5 5.1 6 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Features ................................................. SYSTEM ARCHITECTURE ........................ 14 6.1 6.2 14 6.4 6.5 6.6 6.7 6.8 8 HIGH SPEED CLOCK INPUTS (CLKin0/CLKin0* and CLKin1/CLKin1*) ............................... 14 ............................ SMALL DIVIDER (1 to 8) ........................... LARGE DIVIDER (1 to 1045 ) ...................... CLKout ANALOG DELAY .......................... CLKout12 & CLKout13 DIGITAL DELAY .......... PROGRAMMABLE OUTPUTS ..................... CLOCK DISTRIBUTION 14 14 14 14 15 15 CLOCK OUTPUT SYNCHRONIZATION 6.10 DEFAULT CLOCK OUTPUTS 8.3 DIFFERENTIAL VOLTAGE MEASUREMENT TERMINOLOGY .................................... 13 Features 6.3 7 ........... ..................... Functional Description ............................... 7.1 PROGRAMMABLE MODE ......................... 7.2 PIN CONTROL MODE ............................. 7.3 INPUTS / OUTPUTS ............................... 7.4 INPUT AND OUTPUT DIVIDERS .................. 7.5 FIXED DIGITAL DELAY ............................ 7.6 CLOCK OUTPUT SYNCHRONIZATION (SYNC) .. General Programming Information ................ 8.1 RECOMMENDED PROGRAMMING SEQUENCE . 8.2 REGISTER MAP ................................... 6.9 9 15 15 16 16 16 16 16 16 18 26 26 27 DEFAULT DEVICE REGISTER SETTINGS AFTER POWER ON/RESET ............................... 28 ...................................... ............................ 8.6 REGISTER R3 ...................................... 8.7 REGISTER R4 ...................................... 8.8 REGISTER R5 ...................................... 8.9 REGISTER 15 ...................................... Application Information .............................. 9.1 POWER SUPPLY .................................. 9.2 PIN CONNECTION RECOMMENDATIONS ....... 9.3 THERMAL MANAGEMENT ........................ 9.4 DRIVING CLKin INPUTS ........................... 8.4 REGISTER R0 29 8.5 REGISTER R1 AND R2 31 9.5 33 35 36 37 38 38 40 40 41 TERMINATION AND USE OF CLOCK OUTPUT (DRIVERS) ......................................... 42 Revision History ............................................ Contents Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 46 3 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com 2 Device Information 2.1 Functional Configurations Table 2-1. Clock Output Configurations Bank Input A CLKin0/CLKin0 * CLKin1/CLKin1 * B (1) (2) Clock Group Output CLKoutX/CLK outX* CG1 Output Type Outputs in Divider Group Divider Ratios Delay 0 to 3 LVDS/LVPECL 0 to 3 1 to 8 No CG2 4 to 7 LVDS/LVPECL/ LVCMOS 4 to 7 1 to 8 No CG3 8 to 11 LVDS/LVPECL/ LVCMOS 8 to 11 1 to 8 No CG4 12 and 13 LVDS/LVPECL/ LVCMOS 12 and 13 1 to 1045 Digital and Analog (1) (2) Digital Delay will not work if CLKout12_13_DIV = 1. See Section 3.4 Table 2-2. Pin Control Mode for EN_PIN_CTRL = Low Pin Output Groups Pin=Low Pin=Middle Pin=High CLKoutTYPE_0 CLKout0 to CLKout3 LVDS Powerdown LVPECL CLKoutTYPE_1 CLKout4 to CLKout7 LVDS LVCOMS (Norm/Inv) LVPECL CLKoutTYPE_2 CLKout8 to CLKout13 LVDS LVCMOS (Norm/Inv) LVPECL CLKoutDIV_0 CLKout0 to CLKout3 Divider ÷1 ÷4 ÷2 CLKoutDIV_1 CLKout4 to CLKout7 Divider ÷1 ÷4 ÷2 CLKout8 to CLKout11 Divider ÷1 ÷4 ÷2 CLKout12 to CLKout13 Divider ÷8 ÷ 512 ÷ 16 CLKoutDIV_2 Table 2-3. Pin Control Mode for EN_PIN_CTRL = High (1) (2) Pin CLKoutTYPE_0 (1) (2) 4 Output Groups Pin=Low CLKout0 to CLKout3 LVDS CLKout4 to CLkout7 Pin=Middle LVPECL LVCMOS (Norm/Inv) Pin=High LVPECL CLKoutTYPE_1 CLKout8 to CLKout11 LVDS LVCMOS (Norm/Inv) LVPECL CLKoutTYPE_2 CLKout12 to CLKout13 LVDS LVCMOS (Norm/Inv) LVPECL CLKoutDIV_0 CLKout0 to CLKout7 Dividers ÷1 ÷4 ÷2 CLKoutDIV_1 CLKout8 to CLKout11 Divider ÷1 ÷4 ÷2 CLKoutDIV_2 CLKout12 to CLKout13 Divider ÷4 ÷ 512 ÷ 16 Digital Delay will not work if CLKout12_13_DIV = 1. See Section 3.4 Device Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com CLKout13* CLKout12* CLKout12 45 44 43 42 41 40 Vcc6_CLKin1 CLKout13 46 CLKin1 Vcc8_DIG 47 CLKin1* DATAuWire/ CLKoutDIV_0 48 Vcc7_CLKout 12/13 SYNC1/ CLKoutTYPE_2 CLKuWire/ CLKoutDIV_1 Connection Diagram 39 38 37 LEuWire/ CLKoutDIV_2 1 36 CLKout11 CLKout0 2 35 CLKout11* CLKout0* 3 34 CLKout10* CLKout1* 4 33 CLKout10 CLKout1 5 32 Vcc5_CLKout 8_9_10_11 Vcc1_CLKout 0_1_2_3 6 31 CLKout9 CLKout2 7 30 CLKout9* CLKout2* 8 29 CLKout8* CLKout3* 9 28 CLKout8 CLKout3 10 27 EN_PIN_CTRL Test/ CLKoutTYPE_0 11 26 Bias SYNC0/ CLKoutTYPE_1 12 25 Vcc4_Bias LLP-48 Top Down View 21 22 23 24 CLKout7 CLKout5* 20 CLKout7* CLKout4* 19 CLKout6* 18 CLKout6 17 CLKout5 16 Vcc3_CLKout 4_5_6_7 15 CLKout4 14 Vcc2_CLKin0 13 CLKin0* DAP CLKin0 2.2 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Figure 2-1. 48-Pin Package Table 2-4. Pin Descriptions (1) (1) Pin Number Name(s) I/O Type 1 LEuWire/ CLKoutDIV_2 Description I CMOS / 3-State MICROWIRE Latch Enable Input / Pin control mode: clock divider 2 2, 3 CLKout0 CLKout0* O Programmable Clock output 0: LVDS or LVPECL 4, 5 CLKout1 CLKout1* O Programmable Clock output 1: LVDS or LVPECL 6 Vcc1_CLKout 0_1_2_3 I PWR 7, 8 CLKout2, CLKout2* O Programmable Clock output 2: LVDS or LVPECL 9. 10 CLKout3, CLKout3* O Programmable Clock output 3: LVDS or LVPECL 11 Test/ CLKoutTYPE_0 I CMOS / 3-State Reserved Test Pin / Pin control mode: clock output type select 0 12 SYNC0/ CLKoutTYPE_1 I CMOS / 3-State SYNC0 / Pin control mode: clock output type select 1 13, 14 CLKin0/ CLKin0* I ANLG Clock input 0. Supports clocking types including but not limited to LVDS, LVPECL, and LVCMOS 15 Vcc2_CLKin0 I PWR Power supply for clock input 0 Power supply for clock outputs 0, 1, 2, and 3 See Application Information section Section 9.2 for recommended connections. Device Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 5 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com Table 2-4. Pin Descriptions(1) (continued) 6 Pin Number Name(s) I/O Type 16, 17 CLKout4/ CLKout4* Description O Programmable Clock output 4: LVDS, LVPECL, or LVCMOS 18, 19 CLKout5*/ CLKout5 O Programmable Clock output 5: LVDS, LVPECL, or LVCMOS 20 Vcc3_CLKout 4_5_6_7 I PWR Power supply for clock outputs 4, 5, 6, and 7 21, 22 CLKout6/ CLKout6* O Programmable Clock output 6: LVDS, LVPECL, or LVCMOS 23, 24 CLKout7*/ CLKout7 O Programmable Clock output 7: LVDS, LVPECL, or LVCMOS 25 Vcc4_Bias I PWR Power supply for Bias 26 Bias ANLG Bias bypass pin 27 EN_PIN_CTRL I 3-State Select MICROWIRE or pin control mode 28, 29 CLKout8/ CLKout8* O Programmable Clock output 8: LVDS, LVPECL, or LVCMOS 30, 31 CLKout9*/ CLKout9 O Programmable Clock output 9: LVDS, LVPECL, or LVCMOS 32 Vcc5_CLKout 8_9_10_11 I PWR Power supply for clock outputs 8, 9, 10, and 11 33, 34 CLKout10/ CLKout10* O Programmable Clock output 10: LVDS, LVPECL, or LVCMOS 35, 36 CLKout11*/ CLKout11 O Programmable Clock output 11: LVDS, LVPECL, or LVCMOS 37 Vcc6_CLKin1 I PWR Power supply for clock input 1 38, 39 CLKin1/ CLKin1* I ANLG Clock input 1. Supports clocking types including but not limited to LVDS, LVPECL, and LVCMOS 40 SYNC1/ CLKoutTYPE_2 I CMOS / 3-State 41 Vcc7_CLKout 12_13 I PWR 42, 43 CLKout12/ CLKout12* O Programmable Clock output 12: LVDS, LVPECL, or LVCMOS 44, 45 CLKout13*/ CLKout13 O Programmable Clock output 13: LVDS, LVPECL, or LVCMOS 46 Vcc8_DIG I PWR 47 DATAuWire/ CLKoutDIV_0 I CMOS / 3-State MICROWIRE DATA Pin / Pin control mode: Clock divider 0 48 CLKuWire/ CLKoutDIV_1 I CMOS / 3-State MICROWIRE CLK Pin / Pin control mode: Clock divider 1 DAP DAP GND SYNC pin for CLKin1 and bank B. Pin control mode: Clock output type select 2 Power supply for clock outputs 12, and 13 Power supply for digital DIE ATTACH PAD, connect to GND Device Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 3 Electrical Specifications 3.1 Absolute Maximum Ratings (1) (2) (3) (4) Parameter Symbol Ratings Units VCC -0.3 to 3.6 V Input Voltage VIN -0.3 to (VCC + 0.3) V °C Supply Voltage (1) (5) Storage Temperature Range TSTG -65 to 150 Lead Temperature (solder 4 seconds) TL +260 °C Differential Input Current (CLKinX/X*) IIN ±5 mA Moisture Sensitivty Level MSL 3 "Absolute Maximum Ratings" indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not ensure specific performance limits. For ensured specifications and test conditions, see the Electrical Characteristics. The ensured specifications apply only to the test conditions listed. This device is a high performance RF integrated circuit with an ESD rating up to 2.5 kV Human Body Model, up to 250 V Machine Model and up to 1,250 V Charged Device Model and is ESD sensitive. Handling and assembly of this device should only be done at ESD-free workstations. Stresses in excess of the absolute maximum ratings can cause permanent or latent damage to the device. These are absolute stress ratings only. Functional operation of the device is only implied at these or any other conditions in excess of those given in the operation sections of the data sheet. Exposure to absolute maximum ratings for extended periods can adversely affect device reliability. If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and specifications. Never to exceed 3.6 V. (2) (3) (4) (5) 3.2 Package Thermal Resistance 48-Lead WQFN Parameter Symbol Ratings Units Thermal resistance from junction to ambient on 4layer JEDEC board (1) θJA 26 °C/W θJC 3 °C/W Thermal resistance from junction to case (2) (1) Specification assumes 9 thermal vias connect the die attach pad to the embedded copper plane on the 4-layer JEDEC board. These vias play a key role in improving the thermal performance of the WQFN. It is recommended that the maximum number of vias be used in the board layout. Case is defined as the DAP (die attach pad). (2) 3.3 Recommended Operating Conditions Parameter Symbol Condition Min Typical Max Unit Ambient Temperature TA VCC = 3.3 V -40 25 85 °C Supply Voltage VCC 3.15 3.3 3.45 V Junction Temperature TJ 125 °C Electrical Specifications Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 7 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 3.4 www.ti.com Electrical Characteristics (3.15 V ≤ VCC ≤ 3.45 V, -40 °C ≤ TA ≤ 85 °C. Typical values represent most likely parametric norms at VCC = 3.3 V, TA = 25 °C, at the Recommended Operating Conditions at the time of product characterization and are not ensured.) Symbol Parameter Conditions Min Typ Max Units Current Consumption ICC_PD ICC_CLKS Power Down Supply Current Supply Current with all clocks enabled (1) 1 All clock delays disabled, CLKoutX_Y_DIV = 1, CLKoutX_TYPE = 1 (LVDS), 313 mA 390 mA CLKin0/0* and CLKin1/1* Input Clock Specifications fCLKinX Clock 0 or 1 Input Frequency (2) SLEWCLKin Slew Rate on CLKin DUTYCLKin Clock input duty cycle VCLKin Clock Input, Single-ended Input Voltage VIDCLKin VSSCLKin VIDCLKin Clock Input Differential Input Voltage CLKinX_MUX = Bypassed CLKoutX_Y_DIV = 1 0.001 3100 MHz CLKinX_MUX = Bypassed CLKoutX_Y_DIV = 2 to 8 .001 1600 MHz CLKin_MUX = Divide CLKinX_DIV = 1 to 8 .001 3100 MHz 20% to 80% 0.15 VCLKinX-offset DC offset voltage between CLKinX/CLKinX* CLKinX* - CLKinX VCLKin-VIH Maximum input voltage VCLKin-VIL Minimum input voltage VCLKinX-offset DC offset voltage between CLKinX/CLKinX* CLKinX* - CLKinX V/ns 50 % AC coupled to CLKinX; CLKinX* AC coupled to Ground (CLKinX_BUF_TYPE = Bipolar 0.25 2.4 Vpp AC coupled to CLKinX; CLKinX* AC coupled to Ground (CLKinX_BUF_TYPE = MOS 0.25 2.4 Vpp AC coupled (CLKinX_BUF_TYPE = Bipolar 0.25 1.55 |V| 0.5 3.1 Vpp AC coupled (CLKinX_BUF_TYPE = MOS 0.25 1.55 |V| 3.1 Vpp (3) (4) VSSCLKin 0.5 0.5 Each pin AC coupled CLKinX_BUF_TYPE = Bipolar DC coupled to CLKinX; CLKinX* AC coupled to Ground CLKinX_BUF_TYPE = MOS 0 mV 0 mV 2.0 VCC V 0.0 0.4 V Each pin AC coupled CLKinX_BUF_TYPE = MOS 55 mV Digital Inputs (CLKuWire, DATAuWire, LEuWire) for EN_PIN_CTRL = MIDDLE VIH High-Level Input Voltage VIL Low-Level Input Voltage 1.2 IIH High-Level Input Current VIH = VCC IIL Low-Level Input Current VIL = 0 VCC V 0.4 V -5 5 µA -5 5 µA VCC V 0.4 V Digital Inputs (SYNC0, SYNC1) for EN_PIN_CTRL = MIDDLE VIH (1) (2) (3) (4) 8 High-Level Input Voltage 1.2 VIL Low-Level Input Voltage IIH High-Level Input Current VIH = VCC VIH = VCC -5 5 µA IIL Low-Level Input Current VIL = 0 V VIL = 0 -40 -5 µA For Icc for specific part configuration, see applications section Section 9.1.1 for calculating Icc. The minimum recommended slew rate for all input clocks is 0.5 V/ns. This is especially true for single-ended clocks. Phase noise performance will begin to degrade as the clock input slew rate is reduced. However, the device will function at slew rates down to the minimum listed. When compared to single-ended clocks, differential clocks (LVDS, LVPECL) will be less susceptible to degradation in phase noise performance at lower slew rates due to their common mode noise rejection. However, it is also recommended to use the highest possible slew rate for differential clocks to achieve optimal phase noise performance at the device outputs. See applications section Section 5.1 for definition of VID and VOD voltages. Refer to application note AN-912 Common Data Transmission Parameters and their Definitions (SNLA036) for more information. Electrical Specifications Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Electrical Characteristics (continued) (3.15 V ≤ VCC ≤ 3.45 V, -40 °C ≤ TA ≤ 85 °C. Typical values represent most likely parametric norms at VCC = 3.3 V, TA = 25 °C, at the Recommended Operating Conditions at the time of product characterization and are not ensured.) Symbol Parameter Conditions Min Typ Max Units Digital Inputs (CLKuWire, DATAuWire, LEuWire, SYNC0, SYNC1) for EN_PIN_CTRL= Low or High VIH High-Level Input Voltage 2.6 VCC V VIM Mid-Level Input Voltage 1.3 1.85 V VIL Low-Level Input Voltage 0.7 V 100 µA 10 µA IIH High-Level Input Current IIM Mid-Level Input Current IIL Low-Level Input Current VIH = VCC -10 VIL= 0 -100 µA Clock Skew and Delay CLKoutX to CLKoutY (5) (6) , TSKEW Skew between any two LVCMOS outputs, same CLKout or different CLKout (5), (6) MixedTSKEW CLKoutX CLKoutY FADLY LVDS-to-LVDS, T = 25 °C, FCLK = 800 MHz, RL= 100 Ω AC coupled, Within same Divider 3 LVPECL-to-LVPECL, T = 25 °C FCLK = 800 MHz, RL= 100 Ω emitter resistors = 240 Ω to GND AC coupled, Within same Divider 3 RL = 50 Ω, CL = 10 pF, T = 25 °C, FCLK = 100 MHz, Within same Divider 50 LVPECL to LVDS skew LVDS to LVCMOS skew ps 32 Same device, T = 25 °C, 250 MHz, Within same Divider 830 LVCMOS to LVPECL skew ps 800 Maximum Analog Delay Frequency 1536 MHz 1600 MHz LVDS Clock Outputs (CLKoutX) fCLKout Maximum Clock Frequency (7) (8) RL = 100 Ω Differential Output Voltage VOD (9) (10) ΔVOD Change in Magnitude of VOD for complementary output states 225 T = 25 °C, DC measurement AC coupled to receiver input R = 100 Ω differential termination 400 -50 1.125 1.25 575 mV 50 mV 1.375 V 35 |mV| VOS Output Offset Voltage ΔVOS Change in VOS for complementary output states TR Output Rise Time 20% to 80%, RL = 100 Ω 200 ps TF Output Fall Time 80% to 20%, RL = 100 Ω 300 ps ISA ISB Output short circuit current - single ended Single-ended output shorted to GND, T = 25 °C -24 24 mA ISAB Output short circuit current differential Complimentary outputs tied together -12 12 mA (5) Equal loading and identical clock output configuration on each clock output is required for specification to be valid. Specification not valid for delay mode. (6) Ensured by characterization. (7) Ensured by characterization. (8) Refer to typical performance charts for output operation performance at higher frequencies than the minimum maximum output frequency. (9) See applications section Section 5.1 for definition of VID and VOD voltages. (10) Refer to application note AN-912 Common Data Transmission Parameters and their Definitions (SNLA036) for more information. Electrical Specifications Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 9 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com Electrical Characteristics (continued) (3.15 V ≤ VCC ≤ 3.45 V, -40 °C ≤ TA ≤ 85 °C. Typical values represent most likely parametric norms at VCC = 3.3 V, TA = 25 °C, at the Recommended Operating Conditions at the time of product characterization and are not ensured.) Symbol Parameter Conditions Min Typ Max Units LVPECL Clock Outputs (CLKoutX) TR Output Rise Time 20% to 80%, RL = 100 Ω, emitter resistors = 240 Ω to GND 200 ps TF Output Fall Time 80% to 20%, RL = 100 Ω, emitter resistors = 240 Ω to GND 200 ps Low Common-Mode Voltage PECL (LCPECL) (1), fCLKout Maximum Clock Frequency (3) (4) VOH Output High Voltage VOL Output Low Voltage VOD Output Voltage RL = 100 Ω, emitter resistors = 240 Ω to GND T = 25 °C, DC Measurement Termination = 50 Ω to VCC - 0.6 V (2) 3100 MHz 1.6 V 0.75 535 840 V 1145 mV 1600 mV LVPECL (LVPECL) Clock Outputs (CLKoutX) fCLKout Maximum Clock Frequency (3) (4) VOH Output High Voltage VOL Output Low Voltage VOD Output Voltage RL = 100 Ω, emitter resistors = 240 Ω to GND T = 25 °C, DC Measurement Termination = 50 Ω to VCC - 2.0 V 3100 MHz VCC - 0.94 V VCC - 1.9 585 925 V 1240 mV 2000 mV LVPECL (2VPECL) Clock Outputs (CLKoutX) fCLKout Maximum Clock Frequency (3) (4) VOH Output High Voltage VOL Output Low Voltage VOD Output Voltage RL = 100 Ω, emitter resistors = 240 Ω to GND T = 25 °C, DC Measurement Termination = 50 Ω to VCC - 2.3 V 3100 705 MHz VCC - 0.97 V VCC - 1.95 V 1150 1585 mV LVCMOS Clock Outputs (CLKoutX) fCLKout (3) (4) 5 pF Load 250 VOH Output High Voltage 1 mA Load VCC - 0.1 VOL Output Low Voltage 1 mA Load IOH Output High Current (Source) VCC = 3.3 V, VO = 1.65 V 28 mA IOL Output Low Current (Sink) VCC = 3.3 V, VO = 1.65 V 28 mA Output Duty Cycle (3) VCC/2 to VCC/2, FCLK = 100 MHz, T = 25 °C TR Output Rise Time 20% to 80%, RL = 50 Ω, CL = 5 pF 400 ps TF Output Fall Time 80% to 20%, RL = 50 Ω, CL = 5 pF 400 ps DUTYCLK (1) (2) (3) (4) 10 Maximum Clock Frequency MHz V 0.1 45 50 55 V % For LCPECL, the common mode voltage is regulated (VOH=1.6V, VOL=VOH-Vsw, Vcm=(VOH+VOL)/2 ) and is more stable against with PVT (process, supply, temperature) variations than conventional LVPECL implementations.. With proper selection of external emitter resistors, LCPECL can also be used for DC-coupling with devices with low common voltage such as 0.5V or 0,8V etc. Ensured by characterization. Refer to typical performance charts for output operation performance at higher frequencies than the minimum maximum output frequency. Electrical Specifications Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Electrical Characteristics (continued) (3.15 V ≤ VCC ≤ 3.45 V, -40 °C ≤ TA ≤ 85 °C. Typical values represent most likely parametric norms at VCC = 3.3 V, TA = 25 °C, at the Recommended Operating Conditions at the time of product characterization and are not ensured.) Symbol Parameter Conditions Min Typ Max Units MICROWIRE Interface Timing 3.5 TECS LE to Clock Set Up Time See MICROWIRE Input Timing 25 ns TDCS Data to Clock Set Up Time See MICROWIRE Input Timing 25 ns TCDH Clock to Data Hold Time See MICROWIRE Input Timing 8 ns TCWH Clock Pulse Width High See MICROWIRE Input Timing 25 ns TCWL Clock Pulse Width Low See MICROWIRE Input Timing 25 ns TCES Clock to LE Set Up Time See MICROWIRE Input Timing 25 ns TEWH LE Pulse Width See MICROWIRE Input Timing 25 ns TCR Falling Clock to Readback Time See MICROWIRE Readback Timing 25 ns Serial MICROWIRE Timing Diagram MSB DATAuWire D26 LSB D25 D24 D23 D22 D0 A4 A1 A0 CLKuWire tCES tDCS tCDH tCWH tECS tCWL LEuWire tEWH Figure 3-1. MICROWIRE Timing Diagram Register programming information on the DATAuWire pin is clocked into a shift register on each rising edge of the CLKuWire signal. On the rising edge of the LEuWire signal, the register is sent from the shift register to the register addressed. A slew rate of at least 30 V/µs is recommended for these signals. After programming is complete the CLKuWire, DATAuWire, and LEuWire signals should be returned to a low state. Electrical Specifications Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 11 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com 4 Typical Performance Characteristics Unless otherwise specified: Vdd=3.3V, TA=25 °C 2.0 LVPECL 2V Mode DIFFERENTIAL P-P VOLTAGE (V) DIFFERENTIAL P-P VOLTAGE (V) 1.0 0.8 0.6 0.4 0.2 1.5 LCPECL Mode 0.5 0.0 0.0 0 400 800 1200 1600 FREQUENCY (MHz) 2000 See Section 5.1 for a description of VSS. Figure 4-1. LVDS VSS vs. Frequency 0 3.5 5 pF Load 3.0 60 2.5 ICC (mA) SINGLE ENDED P-P VOLTAGE (V) 1000 1500 2000 2500 3000 FREQUENCY (MHz) 80 10 pF Load 2.0 22 pF Load 1.5 40 1.0 20 0.5 0.0 0 0 100 200 300 400 FREQUENCY (MHz) 500 Figure 4-3. LVCMOS Vpp vs. Frequency 0 -140 -145 -145 -150 LVPECL (differential) -150 Re=240 -155 -160 -165 -170 -175 LVPECL (differential) Re=120 LVDS (differential) -155 -160 -165 -170 LVCMOS -175 -180 10 50 100 150 200 250 300 350 400 FREQUENCY (MHz) Figure 4-4. Typical Dynamic ICC, CL = 5 pF NOISE FLOOR (dBc/Hz) NOISE FLOOR (dBc/Hz) 500 See Section 5.1 for a description of VSS. Figure 4-2. LVPECL VSS vs. Frequency 4.0 -180 100 1k FREQUENCY (MHz) 10k Figure 4-5. LVPECL Noise Floor vs. Frequency 12 LVPECL 1.6V Mode 1.0 10 100 1k FREQUENCY (MHz) 10k See Section 5.1 for a description of VSS. Figure 4-6. LVDS & LVCMOS Noise Floor vs. Frequency Typical Performance Characteristics Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 5 Measurement Definitions 5.1 DIFFERENTIAL VOLTAGE MEASUREMENT TERMINOLOGY The differential voltage of a differential signal can be described by two different definitions causing confusion when reading datasheets or communicating with other engineers. This section will address the measurement and description of a differential signal so that the reader will be able to understand and discern between the two different definitions when used. The first definition used to describe a differential signal is the absolute value of the voltage potential between the inverting and non-inverting signal. The symbol for this first measurement is typically VID or VOD depending on if an input or output voltage is being described. The second definition used to describe a differential signal is to measure the potential of the non-inverting signal with respect to the inverting signal. The symbol for this second measurement is VSS and is a calculated parameter. Nowhere in the IC does this signal exist with respect to ground, it only exists in reference to its differential pair. VSS can be measured directly by oscilloscopes with floating references, otherwise this value can be calculated as twice the value of VOD as described in the first section Figure 5-1 illustrates the two different definitions side-by-side for inputs and Figure 5-2 illustrates the two different definitions side-by-side for outputs. The VID and VOD definitions show VA and VB DC levels that the non-inverting and inverting signals toggle between with respect to ground. VSS input and output definitions show that if the inverting signal is considered the voltage potential reference, the non-inverting signal voltage potential is now increasing and decreasing above and below the non-inverting reference. Thus the peak-to-peak voltage of the differential signal can be measured. VID and VOD are often defined in volts (V) and VSS is often defined as volts peak-to-peak (VPP). VID Definition VSS Definition for Input Non-Inverting Clock VA 2· VID VID VB Inverting Clock VSS = 2· VID VID = | VA - VB | GND Figure 5-1. Two Different Definitions for Differential Input Signals VOD Definition VSS Definition for Output Non-Inverting Clock VA 2· VOD VOD VB Inverting Clock VOD = | VA - VB | VSS = 2· VOD GND Figure 5-2. Two Different Definitions for Differential Output Signals Measurement Definitions Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 13 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com 6 Features 6.1 SYSTEM ARCHITECTURE The LMK01801 is a dual clock buffer which allows separate clock domains on the same IC with options to divide and delay signals. The LMK01801 consists of two separate buffer banks, each with its own input divider, output dividers and programmable control of clock output channels. • Bank A has two clock output groups, see the Section 2.1 for more details. • Bank B has two clock output groups, one of which has analog and digital delay. See the Section 2.1 for more details. Each bank has it own common input divider and is then divided into output groups which share an output divider. The LMK01801 comes in a 48-pin WQFN package. 6.2 HIGH SPEED CLOCK INPUTS (CLKin0/CLKin0* and CLKin1/CLKin1*) The LMK01801 has two clock inputs, CLKin0 and CLKin1 which can be driven differentially or singleended. See Section 9.4 for more information. Each input has a 2 to 8 divider that may be enabled or bypassed. 6.3 CLOCK DISTRIBUTION The LMK01801 features a total of 14 differential outputs. CLKout0 through CLKout7 are driven from CLKin0 and CLKout8 through CLKout13 are driven from CLKin1. 6.4 SMALL DIVIDER (1 to 8) There are three small dividers which drive CLKout0 to CLKout3, CLKout4 to CLKout7, and CLKout8 to CLKout 11. These dividers support a divide range of 1 to 8 (even and odd). 6.5 LARGE DIVIDER (1 to 1045 ) The divider for CLKout12 and CLKout13 supports a divide range of 1 to 1045 (even and odd). When divides of 26 or greater are used, the divider/delay block uses extended mode. 6.6 CLKout ANALOG DELAY Clock outputs 12 and 13 include a fine (analog) delay for phase adjustment of the clock outputs. The fine (analog) delay allows a nominal 25 ps step size and range from 0 to 475 ps of total delay. Enabling the analog delay adds a nominal 500 ps of delay in addition to the programmed value. When adjusting analog delay, glitches may occur on the clock outputs being adjusted. 14 Features Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com 6.7 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 CLKout12 & CLKout13 DIGITAL DELAY CLKout12 and CLKout13 includes a coarse (digital) delay for phase adjustment of the clock outputs. The coarse (digital) delay allows a group of outputs to be delayed by 4.5 to 12 clock distribution path cycles in normal mode, or from 12.5 to 522 clock cycles in extended mode. The delay step can be as small as half the period of the clock distribution path by using the CLKout12_13_HS bit. e.g. 2 GHz clock frequency without using CLKin1 input clock divider results in 250 ps coarse tuning steps. The coarse (digital) delay value takes effect on the clock outputs after a SYNC event. There are 2 different ways to use the digital (coarse) delay. 1. Fixed Digital Delay 2. Relative Dynamic Digital Delay These are further discussed in the Functional Description. 6.8 PROGRAMMABLE OUTPUTS The outputs of the LMK01801 are programmable in a combination of output types based on Table 2-1. Programming the outputs is by MICROWIRE or by pin control mode based on the state of EN_PIN_CTRL pin. Any LVPECL output type can be programmed to LCPECL, 1600, or 2000 mVpp amplitude levels. The 2000 mVpp LVPECL output type is a Texas Instruments proprietary configuration that produces a 2000 mVpp differential swing for compatibility with many data converters and is also known as 2VPECL. 6.9 CLOCK OUTPUT SYNCHRONIZATION Using the SYNC input causes all active clock outputs to share a rising edge. See Section 7.6 for more information. The SYNC event also causes the digital delay value to take effect. 6.10 DEFAULT CLOCK OUTPUTS The power on reset sets the device to operate with all outputs active in bypass mode (no divide) with LVDS output type. In this way the device can be used without programming for fan-out purposes. Features Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 15 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com 7 Functional Description 7.1 PROGRAMMABLE MODE When the EN_PIN_CTRL pin is floating (default by internal pull-up/pull-down) then programming is via MICROWIRE. See Table 2-1 for a description of available programming options for the LMK01801 in programmable mode. 7.2 PIN CONTROL MODE The LMK01801 provides for an alternate function of the MICROWIRE (uWire) pins. This pin control mode is set by the logic of the EN_PIN_CTRL pin to provide limited control of the outputs and dividers. When the EN_PIN_CTRL pin is set high or low (not open) then the output states can be programmed by pins, eliminating the need for an external FPGA or CPU. If EN_PIN_CTRL is LOW then Table 2-2 in Section 2.1 defines how the outputs and dividers are configured. If EN_PIN_CTRL is HIGH then Table 2-3 in Section 2.1 defines how the outputs and dividers are configured. 7.3 7.3.1 INPUTS / OUTPUTS CLKin0 and CLKin1 There are two clock inputs CLKin0 and CLKin1. CLKin0 provides the input for output Bank A and CLKin1 provides the input for the output Bank B. Each input has it's own divider (2 to 8) that may be bypassed. 7.4 INPUT AND OUTPUT DIVIDERS This section discusses the recommended usage of input and output dividers. Clock inputs 0 and 1 each have an associated divider (2 to 8) that may be enabled or bypassed. Clock groups 1, 2 and 3 have small output dividers (1 to 8). Clock group 4 (CLKout12 and CLKout13) has a large output divider (1 to 1045). While the input and output clock dividers may be used in any combination the recommended operating frequency ranges are shown in the table below to minimize the phase noise floor: Table 7-1. Input and Output Divider Input Frequency Ranges 7.5 Input Divider Output Divider Max Frequency Bypassed Divide = 1 3.1 GHz Bypassed Divide > 1 1.6 GHz Divide = 2 to 8 Divide = 1 to 8 3.1 GHz FIXED DIGITAL DELAY This section discusses Fixed Digital Delay and associated registers. Clock outputs 12 and 13 may be delayed relative to CLKout8 to CLKout 11 by up to 517.5 clock distribution path periods if divide is 1 and 518.5 clock distribution path periods if divide is greater than 1. By programming a digital delay value from 4.5 to 522 clock distribution path periods, a relative clock output delay from 0 to 517.5 periods is achieved. The CLKout12_13_DDLY register sets the digital delay as shown in the table Table 7-2. 16 Functional Description Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Table 7-2. Possible Digital Delay Values CLKout12_13_DDLY CLKout12_13_HS Digital Delay 5 1 4.5 5 0 5 6 1 5.5 6 0 6 7 1 6.5 7 0 7 ... ... ... 520 0 520 521 1 520.5 521 0 521 522 1 521.5 522 0 522 The CLKout12_13_DDLY value only takes effect during a SYNC event and if NO_SYNC_CLKout12_13 bit is cleared for this clock group. See Section 7.6 for more information. the The resolution of digital delay is related to the frequency at the input to the Clock Group 4 (CG4) clock distribution path. Digital Delay Resolution = 1 / (2 * Clock Frequency) The digital delay between clock outputs can be dynamically adjusted with minimum or no disruption of the output clocks. See Section 7.6.1 for more information. 7.5.1 Fixed Digital Delay - Example Given a CLKin1 clock frequency of 983.04 MHz as input to CG4, by using digital delay the outputs can be adjusted in 1 / (2 * 983.04 MHz) = ~509 ps steps (Assumes CLKin1_MUX = bypass). To achieve a quadrature (90 degree) phase shift on 122.88 MHz outputs between CLKout12 and CLKout11 from a clock frequency of 983.04 MHz program: • Clock output divider to 8. CLKout8_11 = 8 and CLKout12_13_DIV = 8 • Set clock digital delay value. CLKout12_13_DDLY = 5, CLKout12_13_HS = 0. The frequency of 122.88 MHz has a period of ~8.14 ns. To delay 90 degrees of a 122.88 MHz clock period requires a ~2.03 ns delay. Given a digital delay step of ~509 ps, this requires a digital delay value of 4 steps (2.03 ns / 509 ps = 4). Since the 4 steps are half period steps, CLKout12_13_DDLY is programmed 2 full periods beyond 5 for a total of 7. Table 7-3 shows some of the possible phase delays in degrees achievable in the above example. Table 7-3. Relative phase shift from CLKout12 and CLKout13 to CLKout8 to CLKout11 CLKout12_13_DDLY CLKout12_13_HS Relative Digital Delay Degrees of 122.88 MHz 5 1 -0.5 -23° 5 0 0.0 0° 6 1 0.5 23° 6 0 1.0 45° 7 1 1.5 68° 7 0 2.0 90° 8 1 2.5 113° 8 0 3.0 135° 9 1 3.5 158° Functional Description Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 17 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com Table 7-3. Relative phase shift from CLKout12 and CLKout13 to CLKout8 to CLKout11 (continued) CLKout12_13_DDLY CLKout12_13_HS Relative Digital Delay Degrees of 122.88 MHz 9 0 4.0 180° 10 1 4.5 203° 10 0 5.0 225° 11 1 5.5 248° 11 0 6.0 270° 12 1 6.5 293° 12 0 7.0 315° 13 1 7.5 338° 13 0 8.0 360° ... ... ... ... Figure 7-2 illustrates clock outputs programmed with different digital delay values during a SYNC event. Refer to Section 7.6.1 for more information on dynamically adjusting digital delay. 7.6 CLOCK OUTPUT SYNCHRONIZATION (SYNC) The purpose of the SYNC function is to synchronize the clock outputs with a fixed and known phase relationship between each clock output selected for SYNC. SYNC can also be used to hold the outputs in a low or 0 state. The NO_SYNC_CLKoutX_Y bits can be set to disable synchronization for a clock group. The digital delay value set by CLKout12_13_DDLY takes effect only upon a SYNC event. The digital delay due to CLKout12_13_HS takes effect immediately upon programming. See Section 7.6.1 for more information on dynamically changing digital delay. It is necessary to ensure that the CLKin1 signal is stable before a sync event occurs when CLKout12_13_DIV is greater than 1. 18 Functional Description Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Effect of SYNC When SYNC is asserted, the outputs to be synchronized are held in a logic low state. When SYNC is unasserted, the clock outputs to be synchronized are activated and will transition to a high state simultaneously with one another except where digital delay values have been programmed. Refer to Section 7.6.1 for SYNC functionality when SYNC_QUAL = 1. Table 7-4. Steady State Clock Output Condition Given Specified Inputs SYNC_POL _INV SYNC Pin Clock Steady State 0 0 Active 0 1 Low 1 0 Low 1 1 Active Methods of Generating SYNC There are three methods to generate a SYNC event: • Manual: – Asserting the SYNC pin according to the polarity set by SYNC_POL_INV. – Toggling the SYNC_POL_INV bit though MICROWIRE will cause a SYNC to be asserted. • Automatic: – Programming Register R4 when SYNC_EN_AUTO = 1 will generate a SYNC event for Bank B. – Programming Register R5 when SYNC_EN_AUTO = 1 will generate a SYNC event for both Bank A and Bank B. Due to the high speed of the clock distribution path (as fast as ~322 ps period) and the slow slew rate of the SYNC, the exact clock cycle at which the SYNC is asserted or unasserted by the SYNC is undefined. The timing diagrams show a sharp transition of the SYNC to clarify functionality. Avoiding clock output interruption due to SYNC If a clock output has the NO_SYNC_CLKoutX_Y bits set they will be unaffected by the SYNC event. It is possible to perform a SYNC operation with the NO_SYNC_CLKoutX_Y bit cleared, set the NO_SYNC_CLKoutX_Y bits so that the selected clocks will not be affected by a future SYNC. Future SYNC events will not effect these clocks but will still cause the newly synchronized clocks to be resynchronized using the currently programmed digital delay values. When this happens, the phase relationship between the first group of synchronized clocks and the second group of synchronized clocks will be undefined. Except for CLKout12 and CLKout13 when synced using qualification mode. See Section 7.6.1. SYNC Timing When discussing the timing of the SYNC function, one cycle refers to one period of the clock distribution path. Functional Description Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 19 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com 4.5 cycles CLKout12_13_DDLY & CLKout12_13_HS 6 cycles 5.5 cycles CLKinX SYNC CLKout12 to 13 ÷ 2 CLKout12_13_DDLY & CLKout12_13_HS 5 cycles CLKout12 to 13 ÷ 1 CLKout0 to 11 ÷ 1 A B C D E F G CLKout8_11_DIV = 1 CLKout12_13_DIV = 2 The digital delay for clock outputs 12 and 13 is 5 The digital delay half step for all clock outputs is 0 SYNC1_QUAL = 0 (No qualification) CLKout12_ADLY_SEL & CLKout13_ADLY_SEL is 0 Figure 7-1. Clock Output synchronization using the SYNC1 pin (SYNC1 is Active Low, SYNC1_POL_INV=0) Refer to Figure 7-1 during this discussion on the timing of SYNC. SYNC must be asserted for greater than one clock cycle of the clock distribution path to register the SYNC event. After SYNC is asserted the SYNC event will begin on the following rising edge of the distribution path clock, at time A. After this event has been registered, the outputs will not reflect the low state for 4.5 cycles for CLKout0 - CLKout11 at time B or 5.5 cycles for CLKout12 and CLKout 13 if divide = 1 or 6.5 cycles for CLKout12 and CLKout13 if divide > 1, at time C. Due to the asynchronous nature of SYNC with respect to the output clocks, it is possible that a runt pulse could be created when the clock output goes low from the SYNC event. This is shown by CLKout12-13. See Section 7.6.1.2 for more information on synchronizing relative to an output clock to eliminate or minimize this runt pulse for CLKout12 or CLKout13. After SYNC becomes unasserted the event will be registered on the following rising edge of the distribution path clock, time D. Clock outputs 0 through 11 will rise at time E, coincident with a rising distribution clock edge that occurs after 5 cycles for CLKout0 to CLKout 11 and for CLKout12 to CLKout13 if CLKout12_13_DIV = 1. If CLKout12_13_DIV > 1 then the rising edge of CLKout12-CLKout13 will occur after 6 cycles of the distribution path at time F plus as many more cycles as programmed by the digital delay for that clock output path. The CLKout12 and CLKout13 will rise at time G, which is the Digital Delay value plus 5 cycles when CLKout12_13_DIV = 1 or 6 cycles when CLKout12_13_DIV > 1. See Figure 7-2 for further SYNC timing detail using different digital delays. 20 Functional Description Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 6 cycles CLKout12_13_DDLY & CLKout12_13_HS Distribution Path 5.5 cycles 2.5 cycles 1 cycle 4.5 cycles SYNC Case 1: CLKout12 Case 2: CLKout12 Case 3: CLKout12 A B C D E F Case 1: CLKout12_13_DIV = 2, CLKout12_13_DDLY = 5 Case 2: CLKout12_13_DIV = 2, CLKout12_13_DDLY = 7 Case 3: CLKout12_13_DIV = 2, CLKout12_13_DDLY = 8 Case 1: CLKout12_13_HS = 1 Case 2: CLKout12_13_HS = 0 Case 3: CLKout12_13_HS = 0 SYNC1_QUAL = 0 (No qualification) CLKout12_ADLY_SEL & CLKout13_ADLY_SEL is 0 Figure 7-2. Clock Output synchronization using the SYNC pin (SYNC is Active Low, SYNC_POL_INV=1) Figure 7-2 illustrates the timing with various digital delays programmed. • Time A) SYNC assertion event is registered. • Time B) SYNC unassertion registered. • Time C) All outputs toggle and remain low. A runt pulse can occur at this time as shown. • Time D) After 6 + 4.5 = 10.5 cycles, in Case 1, CLKout12 rises. • Time E) After 6 + 7 = 13 cycles, in Case 2, CLKout12 rises. • Time F) After 6 + 8 = 14 cycles, Case 3, CLKout12 rises. • Note: CLKout 12 and CLKout 13 are driven by the same divider and delay circuit, therefore, their timing is always the same except when analog delay is used. 7.6.1 Dynamically Programming Digital Delay To use dynamic digital delay synchronization qualification set SYNC1_QUAL = 3. This causes the SYNC pulse to be qualified by a clock output so that the SYNC event occurs after a specified time from a clock output transition. This allows the relative adjustment of clock output phase in real-time with no or minimum interruption of clock outputs. Hence the term dynamic digital delay. Note that changing the phase of a clock output requires momentarily altering in the rate of change of the clock output phase and therefore by definition results in a frequency distortion of the signal. Without qualifying the SYNC with an output clock, the newly synchronized clocks would have a random and unknown digital delay (or phase) with respect to clock outputs not currently being synchronized. Only CLKout12 can be used as a qualifying clock. Functional Description Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 21 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com Relative Dynamic Digital Delay When the qualifying clock digital delay is being adjusted, because the qualifying clock and the adjusted clock are the same, then a relative dynamic digital delay adjust is performed. Clocks with NO_SYNC_CLKoutX_Y = 1 are defined as clocks not being adjusted. These clocks operate without interruption. SYNC and Minimum Step Size The minimum step size adjustment for digital delay is half a clock distribution path cycle. This is achieved by using the CLKout12_13_HS bit. The CLKout12_13_HS bit change effect is immediate without the need for SYNC. To shift digital delay using CLKout12_13_DDLY, a SYNC signal must be generated for the change to take effect. Programming Overview To dynamically adjust the digital delay with respect to an existing clock output the device should be programmed as follows: • Set SYNC1_QUAL = 3 for clock output qualification. • Set NO_SYNC_CLKout12_13 = 0 to enable synchronization on CLKout12 and CLKout13. • Set CLKout12_ADLY_SEL = 0. • Set NO_SYNC_CLKoutX_Y = 1 for the output clocks, except CLKout12 and CLKout13, that will continue to operate during the SYNC event. There is no interruption of output on these clocks. • The SYNC_EN_AUTO bit may be set to cause a SYNC event to begin when register R4 is programmed. The auto SYNC feature is a convenience since it does not require the application to manually assert SYNC by toggling the SYNC_POL_INV bit or the SYNC pin when changing digital delay. Internal Dynamic Digital Delay Timing Once SYNC is qualified by an output clock, 1.5 cycles later an internal one shot pulse will occur. The width of the one shot pulse is 3 cycles. This internal one shot pulse will cause the outputs to turn off and then back on with a fixed delay with respect to the falling edge of the qualification clock. This allows for dynamic adjustments of digital delay with respect to an output clock. The qualified SYNC timing is shown in Figure 7-3 for relative dynamic digital delay. Dynamic Digital Delay Conditions To perform a dynamic digital delay adjustment, the analog delay must be bypassed by setting CLKout12_ADLY_SEL to 0. If the analog delay is not bypassed the output synchronization may be inaccurate due to unknown analog delay settings. When adjusting digital delay dynamically, the falling edge of the qualifying clock must coincide with the falling edge of the clock distribution path. For this requirement to be met, program the CLKout12_13_HS value of the qualifying clock group according to Table 7-5. Table 7-5. Half Step programming requirement of qualifying clock during SYNC event 22 CLKout12_13_DIV value CLKout12_13_HS Odd Must = 1 during SYNC event. Even Must = 0 during SYNC event. Functional Description Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com 7.6.1.1 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 RELATIVE DYNAMIC DIGITAL DELAY Relative dynamic digital delay can be used to program a clock output to a specific phase offset from another clock output. Pros: • Direct phase adjustment with respect to same clock output. • Possible glitch pulses from clock output will always be the same during digital delay adjustment transient. Cons: • For some clock divide values there may be a glitch pulse due to SYNC assertion. • Adjustments of digital delay requiring the half step bit (CLKout12_13_HS) for finer digital delay adjust is complicated due to the half step requirement in Table 7-5 above. 7.6.1.2 RELATIVE DYNAMIC DIGITAL DELAY - EXAMPLE To illustrate the relative dynamic digital delay adjust procedure, consider the following example. System Requirements: • CLKin1 Frequency = 983.04 MHz • CLKout8 = 983.04 MHz (CLKout8_11_DIV = 1) • CLKout12 = 491.52 MHz (CLKout12_13_DIV = 2) • During initial programming: – CLKout12_13_DDLY = 5 – CLKout12_13_HS = 0 – NO_SYNC_CLKoutX_Y = 0 The application requires the 491.52 MHz clock to be stepped in 90 degree steps (~508.6 ps), which is the minimum step resolution allowable by the clock distribution path. That is 1 / 983.04 MHz / 2 = ~169.5 ps. During the stepping of the 491.52 MHz clocks the 983.04 MHz clock must not be interrupted. Step 1: The device is programmed from register R0 to R5 with values that result in the device operating as desired, see the system requirements above. The phase of all the output clocks are aligned because all the digital delay and half step values were the same when the SYNC was generated by programming register R5. The timing of this is as shown in Figure 7-1. Step 2: Now the registers will be programmed to prepare for changing digital delay (or phase) dynamically. Register Purpose SYNC1_QUAL = 3 Use clock output for qualifying the SYNC pulse for dynamically adjusting digital delay. NO_SYNC_CLKout7_11 = 1 Clock output 8 (983.04 MHz) won't be affected by SYNC. It will operate without interruption. SYNC1_AUTO = 0 (default) Automatically generation of SYNC is not allowed because of the half step requirement. SYNC must be generated manually by toggling the SYNC_POL_INV bit or the SYNC pin. After the above registers have been programmed, the application may now dynamically adjust the digital delay of the 491.52 MHz clocks. Step 3: Adjust digital delay of CLKout12 by one step. Refer to Table 7-6 for the programming sequence to step one half clock distribution period forward or backwards. Functional Description Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 23 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com Table 7-6. Programming sequence for one step adjust Step direction and current HS state Programming Sequence Adjust clock output one step forward. CLKout12_13_HS = 0. 1. CLKout12_13_HS = 1. Adjust clock output one step forward. CLKout12_13_HS = 1. 1. CLKout12_13_DDLY = 9. 2. Perform SYNC event. 3. CLKout12_13_HS = 0. Adjust clock output one step backward. CLKout12_13_HS = 0. 1. CLKout12_13_HS = 1. 2. CLKout12_13_DDLY = 5. 3. Perform SYNC event. Adjust clock output one step backward. CLKout12_13_HS = 1. 1. CLKout12_13_HS = 0. To fulfill the qualifying clock output half step requirement in Table 7-5 when dynamically adjusting digital delay, the CLKout12_13_HS bit must be set if CLKout12 or CLKout13 has an odd divide. So before any dynamic digital delay adjustment, CLKout12_13_HS must be set because the clock divide value is odd. To achieve the final required digital delay adjustment, the CLKout12_13_HS bit may cleared after SYNC. If a SYNC is to be generated this can be done by toggling the SYNC pin or by toggling the SYNC_POL_INV bit. Because of the internal one shot pulse, no strict timing of the SYNC pin or SYNC_POL_INV bit is required. After the SYNC event, the clock output will be at the specified phase. See Figure 7-3 for a detailed view of the timing diagram. The timing diagram critical points are: • Time A) SYNC assertion event is registered. • Time B) First qualifying falling clock output edge. • Time C) Second qualifying falling clock output edge. • Time D) Internal one shot pulse begins. 5.5 cycles later CLKout12 outputs will be forced low while 8.5 cycles later CLKout8 outputs will be forced low. • Time E) Internal one shot pulse ends. 6 cycles + digital delay cycles later CLKout12 or CLKout13 outputs rise. 10 cycles later CLKout8 to CLKout11 outputs rise. • Time F) CLKout12 to CLKout13 outputs are forced low. • Time G) Beginning of digital delay cycles. • Time H) CLKout8 to CLKout11 outputs are forced low. • Time I) CLKout8 to CLKout11 outputs rise now. • Time j) For CLKout12_13_DDLY = 5; the CLKout12 and CLKout13 outputs rise now. 24 Functional Description Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 CLKout12_13_DDLY & CLKout12_13_HS 6 cycles CLKin1 1.5 cycles 3 cycles Internal One Shot Pulse 6 cycles CLKout12 to 13, ÷ 2 HS = 1 A 1 2 B C D E F G J 10.5 cycles 8.5 cycles CLKout8 to 11, ÷ 2 A B C D E H I (SYNC1_QUAL = 1, Qualify with clock output) Starting condition is after half step is removed (CLKout12_13_HS = 0). Figure 7-3. Relative Dynamic Digital Delay Programming Example, 2nd adjust Functional Description Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 25 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com 8 General Programming Information LMK01801 devices are programmed using 32-bit registers. Each register consists of a 4-bit address field and 23-bit data field. The address field is formed by bits 0 through 3 (LSBs) and the data field is formed by bits 4 through 31 (MSBs). The contents of each register is clocked in MSB first (bit 31), and the LSB (bit 0) last. During programming, the LE signal should be held LOW. The serial data is clocked in on the rising edge of the CLK signal. After the LSB (bit 0) is clocked in the LE signal should be toggled LOW-to-HIGHto-LOW to latch the contents into the register selected in the address field. It is recommended to program registers in numeric order, for example R0 to R5 and R15 to achieve proper device operation. Figure 3-1 illustrates the serial data timing sequence. 8.1 RECOMMENDED PROGRAMMING SEQUENCE Registers are programmed in numeric order with R0 being the first and R15 being the last register programmed. The recommended programming sequence involves programming R0 with the reset bit (b4) set to 1 to ensure the device is in a default state. Then R0 is programmed again, the reset bit is be cleared to 0 during the re-programming of R0. 8.1.1 Overview • • • • • • • 26 R0 (Init): – Program R0 with RESET = 1. This ensures that the device is configured with default settings. When RESET =1, all other R0 bits are ignored. R0: Powerdown Controls and CLKin Dividers – Program R0 with RESET = 0 R1 and R2: Clock output types R3: SYNC Features and Analog Delay for CLKout12 and CLKout13 R4: Dynamic Digital Delay for CLKout12 and CLKout13 R5: CLKout Dividers and Analog Delay Select R15: uWireLock General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com 8.2 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 REGISTER MAP Table 8-1 provides the register map for device programming: Table 8-1. Register Map Register 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 1 CLKout12_TYPE CLKout11_TYPE CLKout10_TYPE 0 0 0 R3 0 0 0 1 0 SYNC0_AUTO SYNC1_FAST R4 0 0 0 0 0 0 0 0 R5 0 0 0 0 R15 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 CLKout9_TYPE 0 0 0 0 0 0 CLKout8_11 _DIV 0 0 0 0 0 CLKout12_13_DIV 0 1 0 0 SYNC1_ QUAL 0 0 0 CLKout0_ TYPE 0 0 0 1 CLKout8_TYPE 0 0 1 0 0 0 1 1 0 1 0 0 0 1 0 1 1 1 1 1 CLKout12_13_ADLY CLKout12_13_DDLY 0 1 CLKout4_7 _DIV 0 1 1 CLKout0_3 _DIV 1 1 uWireLock 0 2 0 CLKout1_ TYPE CLKout12_ADLY_SEL CLKout13_TYPE R2 CLKout2_ TYPE SYNC0_POL_INV CLKout3_ TYPE CLKout13_ADLY_SEL CLKout4_TYPE SYNC1_POL_INV CLKout5_TYPE NO_SYNC_CLKout0_3 CLKout6_TYPE CLKout7_TYPE RESET 1 POWERDOWN CLKin0_DIV CLKout0_3_PD CLKin0_ MUX CLKin1_DIV CLKout4_7_PD CLKin1_ MUX CLKout8_11_PD 0 CLKout12_13_PD 0 CLKin0_BUF_TYPE 0 CLKout12_13_HS 1 NO_SYNC_CLKout4_7 0 NO_SYNC_CLKout8_11 0 SYNC1_AUTO R1 1 NO_SYNC_CLKout12_13 0 SYNC0_FAST R0 3 Address [3:0] CLKin1_BUF_TYPE Data [31:4] General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 27 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 8.3 www.ti.com DEFAULT DEVICE REGISTER SETTINGS AFTER POWER ON/RESET The Default Device Register Settings after Power On/Reset Table below illustrates the default register settings programmed in silicon for the LMK018xx after power on or asserting the reset bit. Capital X and Y represent numeric values. Table 8-2. Default Device Register Settings after Power On/Reset Field Name RESET Default Value (decimal) 0 Register Bit Location (MSB:LSB) R0 4 R0 5 Power down the divider and clock outputs 0 through 3 R0 6 Disabled Power down the divider and clock outputs 4 through 7 R0 7 Disabled Power down the divider and clock outputs 8 through 11 R0 8 Disabled Power down the divider and clock outputs 12 through 13 R0 9 10 Default State Not in reset Field Description Performs power on reset for device Disabled (device is Device power down control active) POWERDOWN 0 CLKout0_3_PD 0 CLKout4_7_PD 0 CLKout8_11_PD 0 CLKout12_13_PD 0 CLKin0_BUF_TYPE 0 Bipolar Clock in buffer type R0 CLKin1_BUF_TYPE 0 Bipolar Clock in buffer type R0 11 CLKin0_DIV 2 Divide by 2 Divider value for CLKin0 R0 14:16 [3] CLKin0_MUX 0 Bypass Enables or bypasses the CLKin0 divider R0 17:18 [2] CLKin1_DIV 2 Divide by 2 Divider value for CLKin1 R0 19:21 [3] CLKin1_MUX 0 Bypass Enables or bypasses the CLKin1 divider R0 22:23 [2] CLKout0_TYPE 1 LVDS R1 4:6 [3] CLKout1_TYPE 1 LVDS CLKout2_TYPE 1 LVDS CLKout3_TYPE 1 CLKout4_TYPE CLKout5_TYPE Disabled R1 7:9 [3] R1 10:12 [3] LVDS R1 13:15 [3] 1 LVDS R1 16:19 [4] 1 LVDS R1 20:23 [4] CLKout6_TYPE 1 LVDS R1 24:27 [4] CLKout7_TYPE 1 LVDS R1 28:31 [4] CLKout8_TYPE 1 LVDS CLKout9_TYPE 1 LVDS CLKout10_TYPE 1 CLKout11_TYPE CLKout12_TYPE Individual clock output format. Select from LVDS/LVPECL. R2 4:7 [4] R2 8:11 [4] LVDS R2 12:15 [4] 1 LVDS R2 16:19 [4] 1 LVDS R2 20:23 [4] CLKout13_TYPE 1 LVDS R2 24:27 [4] CLKout12_13_ADLY 0 CLKout12_13_HS 0 No delay Analog delay setting for CLKout12 & CLKout13. R3 4:9 [6] No Shift Half shift for digital delay. R3 10 Allows SYNC operations to be qualified by a clock output R3 11:12 [2] R3 14 R3 15 R3 16 R3 17 R3 18 R3 19 Not Qualified SYNC1_QUAL 0 SYNC0_POL_INV 1 Logic Low SYNC1_POL_INV 1 Logic Low NO_SYNC_CLKout0_3 0 Will sync NO_SYNC_CLKout4_7 0 Will sync NO_SYNC_CLKout8_11 0 Will sync NO_SYNC_CLKout12_13 0 Will sync 28 Individual clock output format. Select from LVDS/LVPECL/LVCMOS. Sets the polarity of the SYNC pin when input Disable individual clock groups from being synchronized. General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Table 8-2. Default Device Register Settings after Power On/Reset (continued) Default Value (decimal) Default State SYNC0_FAST 0 Disabled SYNC1_FAST 0 Disabled SYNC0_AUTO 1 SYNC1_AUTO 1 CLKout12_13_DDLY 5 CLKout0_3_DIV 1 Divide-by-1 CLKout4_7_DIV 1 Divide-by-1 CLKout8_11_DIV 1 Divide-by-1 CLKout12_ADLY_SEL 0 No Delay CLKout13_ADLY_SEL 0 No Delay CLKout12_13_DIV 1 Divide-by-1 uWireLock 0 Writeable Field Name 8.4 Field Description Register Bit Location (MSB:LSB) R3 23 R3 24 Enables synchronization circuitry. Automatic SYNC is started by programming a Register R5 R3 25 Automatic SYNC is started by programming a Register R4 or R5 R3 26 Digital Delay setting for CLKout12 & CLKout13. R4 4:13 [10] R5 4:6 [3] 5 clock cycles Divider for clock outputs. R5 7:9 [3] R5 10:12 [3] Enable Digital Delay for CLKout12 R5 13 Enable Digital Delay for CLKout 13 R5 14 Divider for clock output. R5 17:27 [11] The values of registers R0 to R5 are lockable R15 4 REGISTER R0 The R0 register controls reset, global power down, the power down functions for the channel dividers and their corresponding outputs, CLKinX divider value and CLKinX divide select. The X, Y in CLKoutX_Y_PD denote the actually clock output which may be from 0 to 13 where X is the first CLKout and Y is the last CLKout. 8.4.1 RESET Setting this bit will cause the silicon default values to be set upon loading of R0 by a high LEuWire pin. When programming register R0 with the RESET bit set, all other programmed values are ignored. The RESET bit is automatically cleared upon writing any other register. For instance, when R0 is written to again with default values. If the user reprograms the R0, after the initial programming then set RESET = 0. Table 8-3. RESET R0[4] 8.4.2 State 0 Normal operation 1 Reset (automatically cleared) POWERDOWN Setting this bit causes the device to enter powerdown mode. Normal operation is resumed by clearing this bit with MICROWIRE. All other MICROWIRE settings are preserved during POWERDOWN. Table 8-4. POWERDOWN R1[5] State 0 Normal operation 1 Powerdown General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 29 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 8.4.3 www.ti.com CLKoutX_Y_PD This bit powers down the clock outputs as specified by CLKoutX to CLKoutY. This includes the divider and output buffers. Table 8-5. CLKoutX_Y_PD Programming Addresses CLKoutX_Y_PD Programming Address CLKout0_3_PD R0[6] CLKout4_7_PD R0[7] CLKout8_11_PD R0[8] CLKout12_13_PD R0[9] Table 8-6. CLKoutX_Y_PD 8.4.3.1 R0[6,7,8,9] State 0 Power up clock group 1 Power down clock group CLKinX_BUF_TYPE There are two input buffer types for CLKin0 and CLKin1: bipolar or CMOS. Bipolar is recommended for differential inputs such as LVDS and LVPECL. CMOS is recommended for DC coupled single ended inputs. When using bipolar, CLKinX and CLKinX* input pins must be AC coupled when using differential or single ended input. When using CMOS, CLKinX and CLKinX* input pins may be AC or DC coupled with a differential input. When using CMOS in a single ended mode, the used clock input pin (CLKinX or CLKinX*) may be AC or DC coupled to the signal source. The unused CLKin shouLd be AC coupled to ground. The programming address table shows at what register the specified CLKinX_BUF_TYPE is located. The CLKinX_BUF_TYPE table shows the programming definition for these registers. Table 8-7. CLKinX_BUF_TYPE Programming Addresses CLKinX_BUF_TYPE Programming Address CLKin0_BUF_TYPE R0[10] CLKin1_BUF_TYPE R0[11] Table 8-8. CLKinX_BUF_TYPE 8.4.3.2 R0[10] CLKinX Buffer Type 0 Bipolar 1 CMOS CLKinX_DIV These set the CLKin divide value, from 2-8. Table 8-9. CLKinX_DIV Programming Address 30 CLKinX_DIV Programming Address CLKin0_DIV R0[16:14] CLKin1_DIV R0[21:19] General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Table 8-10. CLKinX_DIV 8.4.3.3 R0[21:19, 16:14] Divide Value 0 (0x00) 8 1 (0x01) 2 2 (0x02) 2 3 (0x03) 3 4 (0x04) 4 5 (0x05) 5 6 (0x06) 6 7 (0x07) 7 CLKinX_MUX These bits select whether or not the CLKin divider is bypassed or enabled. Table 8-11. CLKinX_MUX Programming Address CLKinX_MUX Programming Address CLKin0_MUX R0[18:17] CLKin1_MUX R0[23:22] Table 8-12. CLKinX_MUX 8.5 R0[23:22, 18:17] State 0 (0x00) Bypass 1(0x01) Divide REGISTER R1 AND R2 Registers R1 and R2 set the clock output types. 8.5.1 CLKoutX_TYPE The clock output types of the LMK01801 are individually programmable. The CLKoutX_TYPE registers set the output type of an individual clock output to LVDS, LVPECL, LVCMOS, or powers down the output buffer. Note that LVPECL supports three different amplitude levels and LVCMOS supports single LVCMOS outputs, inverted, and normal polarity of each output pin for maximum flexibility. The programming addresses table shows at what register and address the specified clock output CLKoutX_TYPE register is located. The CLKoutX_TYPE table shows the programming definition for these registers. General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 31 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com Table 8-13. CLKoutX_TYPE Programming Addresses CLKoutX Programming Address CLKout0 R1[4:6] CLKout1 R1[7:9] CLKout2 R1[10:12] CLKout3 R1[13:15] CLKout4 R1[16:19] CLKout5 R1[20:23] CLKout6 R1[24:27] CLKout7 R1[28:31] CLKout8 R2[4:7] CLKout9 R2[8:11] CLKout10 R2[12:15] CLKout11 R2[16:19] CLKout12 R2[20:23] CLKout13 R2[24:27] Table 8-14. CLKoutX_TYPE, 4 bits 32 R1[31:28,27:24,23:20,19:16], R2[27:24,23:20,19:16,15:12,11:8,7:4] Definition 0 (0x00) Powerdown 1 (0x01) LVDS 2 (0x02) LCPECL 3 (0x03) Reserved 4 (0x04) LVPECL (1600 mVpp) 5 (0x05) LVPECL (2000 mVpp) 6 (0x06) LVCMOS (Norm/Inv) 7 (0x07) LVCMOS (Inv/Norm) 8 (0x08) LVCMOS (Norm/Norm) 9 (0x09) LVCMOS (Inv/Inv) 10 (0x0A) LVCMOS (Off/Norm) 11 (0x0A) LVCMOS (Off/Inv) 12 (0x0C) LVCMOS (Norm/Off) 13 (0x0D) LVCMOS (Inv/Off) 14 (0x0E) LVCMOS (Off/Off) General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com 8.6 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 REGISTER R3 Register R3 sets the analog delay, digital delay half-shift and SYNC controls. 8.6.1 CLKout12_13_ADLY This registers controls the analog delay of the clock outputs 12 and 13. Adding analog delay to the output will increase the noise floor of the output. For this analog delay to be active for a clock output, it must be selected with ADLY12_SEL or ADLY13_SEL. If neither clock output selects the analog delay, then the analog delay block is powered down. In addition to the programmed delay, a fixed 500 ps of delay will be added by engaging the delay block. The CLKout12_13_ADLY table shows the programming definition for these registers. Table 8-15. CLKout12_13_ADLY, 6bits 8.6.2 R3[4:9] Definition 0 (0x00) 500 ps + No delay 1 (0x01) 500 ps + 25 ps 2 (0x02) 500 ps + 50 ps 3 (0x03) 500 ps + 75 ps 4 (0x04) 500 ps + 100 ps 5 (0x05) 500 ps + 125 ps 6 (0x06) 500 ps + 150 ps 7 (0x07) 500 ps + 175 ps 8 (0x08) 500 ps + 200 ps 9 (0x09) 500 ps + 225 ps 10 (0x0A) 500 ps + 250 ps 11 (0x0B) 500 ps + 275 ps 12 (0x0C) 500 ps + 300 ps 13 (0x0D) 500 ps + 325 ps 14 (0x0E) 500 ps + 350 ps 15 (0x0F) 500 ps + 375 ps 16 (0x10) 500 ps + 400 ps 17 (0x11) 500 ps + 425 ps 18 (0x12) 500 ps + 450 ps 19 (0x13) 500 ps + 475 ps 20 (0x14) 500 ps + 500 ps 21 (0x15) 500 ps + 525 ps 22 (0x16) 500 ps + 550 ps 23 (0x17) 500 ps + 575 ps CLKout12_13_HS, Digital Delay Half Shift This bit subtracts a half clock cycle of the clock distribution path period to the digital delay of CLKout12 and CLKout13. CLKout12_13_HS is used together with CLKout12_13_DDLY to set the digital delay value. The state of this bit does not affect the power mode of the clock output group. When changing CLKout12_13_HS, the digital delay immediately takes effect without a SYNC event. Table 8-16. CLKout12_13_HS R3[10] State 0 Normal General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 33 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com Table 8-16. CLKout12_13_HS (continued) 8.6.3 R3[10] State 1 Subtract half of a clock distribution path period from the total digital delay SYNC1_QUAL When SYNC1_QUAL is set clock outputs on Bank B will be synchronized. CLKout12 will be used as the SYNC qualification clock. Only CLKout12 and CLKout13 support dynamic digital delay. However, this permits the relative phase relationship between CLKout 12 and CLKout13 to be dynamically adjusted with respect to all other clock outputs. When NO_SYNC_CLKoutX_Y = 1, the corresponding clock outputs will not be interrupted during the SYNC event. Qualifying the SYNC means that the pulse which turns the clock outputs off and on will have a fixed time relationship with the phase of the other clock outputs. See Section 6.9 for more information. Table 8-17. SYNC1_QUAL 8.6.4 R3[11] Mode 0 (0x00) No Qualification 1 (0x01) Reserved 2 (0x10) Reserved 3 (0x11) Qualification Enabled SYNCX_POL_INV Sets the polarity of a SYNCX input pin. When SYNC is asserted the clock outputs will transition to a low state. A pull-up on the SYNCX pin results in normal operation when the SYNCX_POL_INV = 1 and the SYNCX input is a no connect. See Section 7.6 for more information on SYNC. A SYNC event can be generated by toggling this bit through the MICROWIRE interface. Table 8-18. SYNCX_POL_INV 8.6.5 R3[14, 15] Polarity 0 SYNC is active high 1 SYNC is active low NO_SYNC_CLKoutX_Y The NO_SYNC_CLKoutX_Y bits prevent individual clock groups from becoming synchronized during a SYNC event. A reason to prevent individual clock groups from becoming synchronized is that during synchronization, the clock output is in a fixed low state or can have a glitch pulse. By disabling SYNC on a clock group, it will continue to operate normally during a SYNC event. Digital delay requires a SYNC operation to take effect. If NO_SYNC_CLKout12_13 is set before a SYNC event, the digital delay value will be unused. Setting the NO_SYNC_CLKoutX_Y bit has no effect on clocks already synchronized together. 34 General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Table 8-19. NO_SYNC_CLKoutX_Y Programming Addresses NO_SYNC_CLKoutX_Y Programming Address CLKout0 toCLKout3 R3[16] CLKout4 to CLKout7 R3[17] CLKout8 to CLKout11 R3[18] CLKout12 to CLKout13 R3[19] Table 8-20. NO_SYNC_CLKoutX_Y 8.6.6 R3[19, 18, 17, 16] Definition 0 CLKoutX_Y will synchronize 1 CLKoutX_Y will not synchronize SYNCX_FAST SYNC1_FAST must be set to 1 when using SYNC1_QUAL 8.6.7 SYNCX_AUTO When set, causes a SYNC event to occur when programming R4 to adjust digital delay values (this will cause a SYNC event for Bank B only) or R5 when adjusting divide values (this will cause a SYNC event for both Bank A and B). The SYNC event will coincide with the LE uWire pin falling edge. Table 8-21. SYNCX_AUTO 8.7 8.7.1 R3[26, 25] Mode 0 Manual SYNC 1 SYNC internally generated REGISTER R4 CLKout12_13_DDLY, Clock Channel Digital Delay CLKout12_13_DDLY and CLKout12_13_HS sets the digital delay used for CLKout12 and CLKout13. CLKout12_13_DDLY only takes effect during a SYNC event and if the NO_SYNC_CLKout12_13 bit is cleared for this clock group. Programming CLKout12_13_DDLY can require special attention. See section Section 7.6.1 for more details. Using a CLKout12_13_DDLY value of 13 or greater will cause the clock outputs to operate in extended mode regardless of the clock group's divide value or the half step value. One clock cycle is equal to the period of the clock distribution path. The period of the clock distribution path is equal to clock divider value divided by the CLKin1 frequency. tclock distribution path = CLKout divide value / fCLKin General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 35 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com Table 8-22. CLKout12_13_DDLY, 10 bits 8.8 R4[13:4] Delay (Divide = 1) Delay (Divide >1) Power Mode 0 (0x00) 5 clock cycles 6 clock cycles 1 (0x01) 5 clock cycles 6 clock cycles 2 (0x02) 5 clock cycles 6 clock cycles 3 (0x03) 5 clock cycles 6 clock cycles 4 (0x04) 5 clock cycles 6 clock cycles 5 (0x05) 5 clock cycles 6 clock cycles 6 (0x06) 6 clock cycles 7 clock cycles 7 (0x07) 7 clock cycles 8 clock cycles ... ... ... 12 (0x0C) 12 clock cycles 13 clock cycles 13 (0x0D) 13 clock cycles 14 clock cycles ... ... ... 520 (0x208) 520 clock cycles 521 clock cycles 521 (0x209) 521 clock cycles 522 clock cycles 522 (0x20A) 522 clock cycles 523 clock cycles Normal Mode Extended Mode REGISTER R5 Register 5 sets the clock output dividers and analog delay. 8.8.1 CLKout12_ADLY_SEL[13], CLKout13_ADLY_SEL[14], Select Analog Delay These bits individually select the analog delay block for use with CLKout12 or CLKout13. It is not required for both outputs of a clock output group to use analog delay, but if both outputs do select the analog delay block, then the analog delay will be the same for each output. When neither clock output uses analog delay, the analog delay block is powered down. Table 8-23. CLKout12_ADLY_SEL[13], CLKout13_ADLY_SEL[14] 8.8.2 R5[13] R5[14] State 0 0 Analog delay powered down 0 1 Analog delay on CLKout13 1 0 Analog delay on CLKout12 1 1 Analog delay on both CLKouts CLKoutX_Y_DIV. Clock Output Divide CLKoutX_Y_DIV sets the divide value for the clock outputs X through Y. The divide may be even or odd. Both even and odd divides output a 50% duty cycle clock. Programming CLKoutX_Y_DIV is as follows: Table 8-24. CLKoutX_Y_DIV Programming Addresses 36 CLKoutX_Y_DIV Programming Address CLKout0_3_DIV R5[6:4] CLKout4_7_DIV R5[9:7] CLKout8_11_DIV R5[12:10] CLKout12_13_DIV R5[27:17] General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Table 8-25. CLKoutX_Y_Div, 2 bits R5[12:10, 9:7, 6:4] Divide Value 0 (0x00) 8 1 (0x01) 1 2 (0x02) 2 3 (0x03) 3 4 (0x04) 4 5 (0x05) 5 6 (0x06) 6 7 (0x07) 7 Table 8-26. CLKout12_13_DIV, 11 bits R5[27:17] Divide Value 0 (0x00) Invalid 1 (0x01) 1 2 (0x02) 2 (1) 3 (0x03) (1) Power Mode 3 4 (0x04) 4 (1) 5 (0x05) 5 (1) 6 (0x06) 6 ... ... 24 (0x18) 24 25 (0x19) 25 26 (0x1A) 26 27 (0x1B) 27 ... ... 1044 (0x414) 1044 1045 (0x415) 1045 Normal Mode Extended Mode After programming CLKout12_13_DIV a SYNC event must occur on the channels using this divide value (CLKout 12 and CLKout13), A SYNC event may be generated by changing the SYNC1_POL_INV bit or through the SYNC1 pin. Ensure that CLKin1 is stable before this SYNC event occurs. Using a divide value of 26 or greater will cause the clock group to operate in extended mode regardless of the clock group's digital delay value. 8.9 8.9.1 REGISTER 15 uWireLock Setting uWireLock will prevent any changes to uWire registers R0 to R5. Only by clearing uWireLock bit in R15 can the MICROWIRE registers be unlocked and written to once more. Table 8-27. uWireLock R15 [4] State 0 Registers Unlocked 1 Registers locked, Write-protected General Programming Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 37 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com 9 Application Information 9.1 9.1.1 POWER SUPPLY Current Consumption NOTE Assuming θJA = 25.8 °C/W, the total power dissipated on chip must be less than (125 °C - 85 °C) / 25.8 °C/W = 1.5 W to ensure a junction temperature less than 145 °C. Worst case power dissipation can be estimated by multiplying typical power dissipation with a factor of 1.20. From Table 9-1 the current consumption can be calculated for any configuration. For example, the current for the entire device with 1 LVDS (CLKout0) and 1 LVPECL 1600 mVpp /w 240 Ω emitter resistors (CLKout1) output active with a clock output divide = 1, and no other features enabled can be calculated by adding the following blocks: • Core Current • Clock Buffer • One LVDS Output Buffer Current • Bank A • Output Divider Buffer Current • LVPECL 1600 mVpp buffer /w 240 Ω emitter resistors Since there will be one LVPECL output drawing emitter current, this means some of the power from the current draw of the device is dissipated in the external emitter resistors which doesn't add to the power dissipation budget for the device but is important for LDO ICC calculations. For total current consumption of the device add up the significant functional blocks. In this example 92 mA = • 1 mA (core current) • 22 mA (Bank A current) • 15 mA (Output Buffer current) • 21 mA (Output Divider current) • 9 mA (LVDS output current) • 24 mA (LVPECL 1600 mVpp buffer /w 240 Ω emitter resistors) Once the total current consumption has been calculated, power dissipated by the device can be calculated. The power dissipation of the device is equel to the total current entering the device multiplied by the voltage at the device minus the power dissipated in any emitter resistors connected to any of the LVPECL outputs. If no emitter resistors are connected to the LVPECL outputs, this power will be 0 watts. Continuing the output with 240 Ω emitter resistors. Total IC power = 275.1 mW = 3.3 V * 95 mA -28.5 mW. 38 Application Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Table 9-1. Typical Current Consumption for Selected Functional Blocks (TA = 25 °C, VCC = 3.3 V) Block Typical ICC (mA) Condition Power dissipated in device (mW) Power dissipated externally (mW) (1) Core Core Bank 1 3.3 - Bank A All outputs and dividers off At least on output enabled 22 72.6 - Bank B At least on output enabled 25 82.5 - CLKout0 to CLKout3 Buffers - CLKout4 to CLKout7 On when any on output in the group is enabled CLKout8 to CLKout11 15 - 49.5 - CLKout12 to CLKout13 Divide = 1 21 69.3 - Divide = 2 to 8 24.2 79.8 - Divide = 1 to 25 and DDLY = 1 to 12 15 49.5 - Divide = 26 to 1045 or DDLY > 13 19.1 63.0 - 9 29.7 CLKout12_13_ADLY = 0 to 3 3.4 11.2 - CLKout12_13_ADLY = 4 to 7 3.8 12.5 - CLKout12_13_ADLY = 8 to 11 4.2 13.9 - CLKout12_13_ADLY = 12 to 15 4.7 15.5 - CLKout12_13_ADLY = 16 to 23 5.2 17.2 - 2.8 9.2 - CLkout0 to CLKout11; 100 Ω differential termination 9 29.7 - CLkout12 to CLKout13; 100 Ω differential termination 14 46.2 - CLkout0 to CLKout11; LVPECL 1600 mVpp, AC coupled using 240 Ω emitter resistors 24 79.2 28.5 CLkout12 to CLKout13; LVPECL 1600 mVpp, AC coupled using 240 Ω emitter resistors 29.5 97.3 28.5 10 MHz 18.6 61.4 - 50 MHz 23.1 76.2 - 150 MHz 31.7 104.6 - 10 MHz 24.7 81.51 - 50 MHz 30.3 100 - 150 MHz 42.0 138.6 - CLKout0 to CLKout11 Output Divider CLKout12 and CLKout13 Input Divider Analog Delay Bank A Divide = 2 to 8 Bank B Divide = 2 to 8 Analog Delay Value When only one, CLKout12 or CLKout13, have Analog Delay Selected. - Clock Output Buffers LVDS LVPEC L LVCMOS Pair, CLKout4 to CLKout11, (CLKoutX_TYPE = 6 - 10), CL = 5 pF LVCMOS Pair, CLKout12 and CLKout13, (CLKoutX_TYPE = 6 - 10), CL = 5 pF LVCMO S LVCMOS Single, CLKout4 to CLKout11, (CLKoutX_TYPE=11 - 13), CL = 5 pF LVCMOS Single, CLKout12 and CLKout13, (CLKoutX_TYPE= 11 - 13), CL = 5 pF (1) 10 MHz 9.7 32 - 50 MHz 10.8 35.6 - 150 MHz 13.5 44.5 - 10 MHz 15 49.5 - 50 MHz 17.5 57.7 - 150 MHz 22.8 75.2 - Power is dissipated externally in LVPECL emitter resistors. The externally dissipated power is calculated as twice the DC voltage level of one LVPECL clock output pin squared over the emitter resistance. That is to say power dissipated in emitter resistors = 2 * Vem2/Rem Application Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 39 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 9.2 9.2.1 www.ti.com PIN CONNECTION RECOMMENDATIONS Vcc Pins and Decoupling All Vcc pins must always be connected. Integrated capacitance on the IC makes high frequency decoupling capacitors unnecessary. Ferrite beads should be used on CLKout Vcc pins to minimize crosstalk through power supply. When several clocks share the same frequency, a single ferrite bead can be shared with the common frequency CLKout Vcc's for power supply isolation. 9.2.2 Unused clock outputs Leave unused clock outputs floating and powered down. 9.2.3 Unused clock inputs Unused clock inputs can be left floating. 9.2.4 Bias Proper bypassing of the Bias pin with a 1 µF capacitor connected to Vcc4_Bias (Pin 25) is important for low noise performance. 9.2.5 In MICROWIRE Mode SYNC0 and SYNC1 have an internal pullup and may be left as a no-connect if external SYNC is not required. MIRCROWIRE SYNC may still be used in this condition. 9.3 THERMAL MANAGEMENT Power consumption of the LMK01801 can be high enough to require attention to thermal management. For reliability and performance reasons the die temperature should be limited to a maximum of 125 °C. That is, as an estimate, TA (ambient temperature) plus device power consumption times θJA should not exceed 125 °C. The package of the device has an exposed pad that provides the primary heat removal path as well as excellent electrical grounding to a printed circuit board. To maximize the removal of heat from the package a thermal land pattern including multiple vias to a ground plane must be incorporated on the PCB within the footprint of the package. The exposed pad must be soldered down to ensure adequate heat conduction out of the package. A recommended footprint including recommended solder mask and solder paste layers can be found at: http://www.ti.com/packaging for the RHS0048A package. 40 Application Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com 9.4 9.4.1 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 DRIVING CLKin INPUTS Driving CLKin Pins with a Differential Source Both CLKin ports can be driven by differential signals. It is recommended that the input mode be set to bipolar (CLKinX_BUF_TYPE = 0) when using differential reference clocks. The LMK01801 family internally biases the input pins so the differential interface should be AC coupled. The recommended circuits for driving the CLKin pins with either LVDS or LVPECL are shown in Figure 9-1 and Figure 9-2. 100: Trace (Differential) LVDS 100: CLKinX 0.1 PF LMK01801 Input 0.1 PF CLKinX* 240: Figure 9-1. CLKinX/X* Termination for an LVDS Reference Clock Source LVPECL Ref Clk 0.1 PF 0.1 PF 100: Trace (Differential) 100: CLKinX 0.1 PF LMK01801 Input 0.1 PF 240: CLKinX* Figure 9-2. CLKinX/X* Termination for an LVPECL Reference Clock Source Finally, a reference clock source that produces a differential sine wave output can drive the CLKin pins using the circuit shown in Figure 9-3. Note: the signal level must conform to the requirements for the CLKin pins listed in the Section 3.4. 100: Trace (Differential) 100: CLKinX 0.1 PF 0.1 PF Differential Sinewave Clock Source LMK01801 Input CLKinX* Figure 9-3. CLKinX/X* Single-ended Termination 9.4.2 Driving CLKin Pins with a Single-Ended Source The CLKin pins of the LMK01801 family can be driven using a single-ended reference clock source, for example, either a sine wave source or an LVCMOS/LVTTL source. Either AC coupling or DC coupling may be used. In the case of the sine wave source that is expecting a 50 Ω load, it is recommended that AC coupling be used as shown in Figure 9-4 the circuit below with a 50 Ω termination. NOTE The signal level must conform to the requirements for the CLKin pins listed in the Section 3.4. CLKinX_BUF_TYPE is recommended to be set to bipolar mode (CLKinX_BUF_TYPE = 0). Application Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 41 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com 0.1 PF 50: Trace Clock Source CLKinX 50: 0.1 PF LMK01801 CLKinX* Figure 9-4. DC Coupled LVCMOS/LVTTL Reference Clock If the CLKin pins are being driven with a single-ended LVCMOS/ LVTTL source, either DC coupling or AC coupling may be used. If DC coupling is used, see Figure 9-5, the CLKinX_BUF_TYPE should be set to MOS buffer mode (CLKinX_BUF_TYPE = 1) and the voltage swing of the source must meet the specifications for DC coupled, MOS-mode clock inputs given in the table of Electrical Characteristics. If AC coupling is used, the CLKinX_BUF_TYPE should be set to the bipolar buffer mode (CLKinX_BUF_TYPE = 0). The voltage swing at the input pins must meet the specifications for AC coupled, bipolar mode clock inputs given in the table of Electrical Characteristics. In this case, some attenuation of the clock input level may be required. A simple resistive divider circuit before the AC coupling capacitor is sufficient. Figure 9-5. DC Coupled LVCMOS/LVTTL Reference Clock 9.5 TERMINATION AND USE OF CLOCK OUTPUT (DRIVERS) When terminating clock drivers keep in mind these guidelines for optimum phase noise and jitter performance: • Transmission line theory should be followed for good impedance matching to prevent reflections. • Clock drivers should be presented with the proper loads. For example: – LVDS drivers are current drivers and require a closed current loop. – LVPECL drivers are open emitters and require a DC path to ground. • Receivers should be presented with a signal biased to their specified DC bias level (common mode voltage) for proper operation. Some receivers have self-biasing inputs that automatically bias to the proper voltage level. In this case, the signal should normally be AC coupled. It is possible to drive a non-LVPECL or non-LVDS receiver with an LVDS or LVPECL driver as long as the above guidelines are followed. Check the datasheet of the receiver or input being driven to determine the best termination and coupling method to be sure that the receiver is biased at its optimum DC voltage (common mode voltage). For example, when driving the OSCin/OSCin* input of the LMK04800 family, OSCin/OSCin* should be AC coupled because OSCin/ OSCin* biases the signal to the proper DC level. This is only slightly different from the AC coupled cases described in Section 9.4.2 because the DC blocking capacitors are placed between the termination and the OSCin/OSCin* pins, but the concept remains the same. The receiver (OSCin/OSCin*) sets the input to the optimum DC bias voltage (common mode voltage), not the driver. 42 Application Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com 9.5.1 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 Termination for DC Coupled Differential Operation For DC coupled operation of an LVDS driver, terminate with 100 Ω as close as possible to the LVDS receiver as shown in Figure 9-6. 100: CLKoutX 100: Trace (Differential) LVDS Driver LVDS Receiver CLKoutX* Figure 9-6. Differential LVDS Operation, DC Coupling, No Biasing of the Receiver For DC coupled operation of an LVPECL driver, terminate with 50 Ω to VCC - 2 V as shown in Figure 9-7. Alternatively terminate with a Thevenin equivalent circuit (120 Ω resistor connected to VCC and an 82 Ω resistor connected to ground with the driver connected to the junction of the 120 Ω and 82 Ω resistors) as shown in Figure 9-8 for VCC = 3.3 V. 50: Vcc - 2 V CLKoutX 100: Trace (Differential) LVPECL Driver LVPECL Receiver 50: CLKoutX* Vcc - 2 V Figure 9-7. Differential LVPECL Operation, DC Coupling 82: 120: Vcc CLKoutX 100: Trace (Differential) LVPECL Driver LVPECL Receiver 82: 120: CLKoutX* Vcc Figure 9-8. Differential LVPECL Operation, DC Coupling, Thevenin Equivalent 9.5.2 Termination for AC Coupled Differential Operation AC coupling allows for shifting the DC bias level (common mode voltage) when driving different receiver standards. Since AC coupling prevents the driver from providing a DC bias voltage at the receiver it is important to ensure the receiver is biased to its ideal DC level. When driving non-biased LVDS receivers with an LVDS driver, the signal may be AC coupled by adding DC blocking capacitors, however the proper DC bias point needs to be established at the receiver. One way to do this is with the termination circuitry in Figure 9-9. Application Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 43 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com 0.1 PF 100: Trace (Differential) LVDS Driver 50: CLKoutX LVDS Receiver 50: Vbias CLKoutX* 0.1 PF Figure 9-9. Differential LVDS Operation, AC Coupling, External Biasing at the Receiver Some LVDS receivers may have internal biasing on the inputs. In this case, the circuit shown in is modified by replacing the 50 Ω terminations to Vbias with a single 100 Ω resistor across the input pins of the receiver, as shown in Figure 9-10. When using AC coupling with LVDS outputs, there may be a startup delay observed in the clock output due to capacitor charging. The previous figures employ a 0.1 μF capacitor. This value may need to be adjusted to meet the startup requirements for a particular application. 100: 0.1 PF 100: Trace (Differential) LVDS Driver LVDS Receiver 0.1 PF Figure 9-10. LVDS Termination for a Self-Biased Receiver LVPECL drivers require a DC path to ground. When AC coupling an LVPECL signal use 120 Ω to 240 Ω emitter resistors close to the LVPECL driver to provide a DC path to ground as shown in Figure 9-11. For proper receiver operation, the signal should be biased to the DC bias level (common mode voltage) specified by the receiver. The typical DC bias voltage for LVPECL receivers is 2 V. CA 0.1 PF LVPECL Driver 0.1 PF 100: Trace (Differential) 100: CLKoutX Rem A typical application is shown in Figure 9-11, where Rem=120 Ω to 240 Ω. Refer to the reciever input recommendations to determine if the proper value of CA's, if needed. CA Differential Input Rem CLKoutX* Figure 9-11. Differential LVPECL Operation, AC Coupling, External Biasing at the Receiver, Rem=120 Ω to 240 Ω 9.5.3 Termination for Single-Ended Operation A balun can be used with either LVDS or LVPECL drivers to convert the balanced, differential signal into an unbalanced, single-ended signal. 44 Application Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 LMK01801 www.ti.com SNAS573A – JANUARY 2012 – REVISED APRIL 2013 It is possible to use an LVPECL driver as one or two separate 800 mVpp signals. When using only one LVPECL driver of a CLKoutX/CLKoutX* pair, be sure to properly terminated the unused driver. When DC coupling one of the LMK04800 family clock LVPECL drivers, the termination should be 50 Ω to VCC - 2 V as shown in Figure 9-12. The Thevenin equivalent circuit is also a valid termination as shown in Figure 913 for Vcc = 3.3 V. 50: Vcc - 2V CLKoutX 50: Trace LVPECL Driver Vcc - 2V CLKoutX* Load 50: Figure 9-12. Single-Ended LVPECL Operation, DC Coupling CLKoutX Vcc 50: Trace 120: LVPECL Driver CLKoutX* 82: 120: Vcc 82: Load Figure 9-13. Single-Ended LVPECL Operation, DC Coupling, Thevenin Equivalent 0.1 PF LVPECL Driver 50: Trace 50: CLKoutX* 120: 0.1 PF 50: CLKoutX 120: When AC coupling an LVPECL driver use a 120 Ω to 240 Ω emitter resistor to provide a DC path to ground and ensure a 50 Ω termination with the proper DC bias level for the receiver. The typical DC bias voltage for LVPECL receivers is 2 V (See Section 9.5.2). If the companion driver is not used it should be terminated with either a proper AC or DC termination. This latter example of AC coupling a single-ended LVPECL signal can be used to measure single-ended LVPECL performance using a spectrum analyzer or phase noise analyzer. When using most RF test equipment no DC bias point (0 VDC) is required for safe and proper operation. The internal 50 Ω termination of the test equipment correctly terminates the LVPECL driver being measured as shown in Figure 9-14. Load Figure 9-14. Single-Ended LVPECL Operation, AC Coupling Rem=120 Ω to 240 Ω Application Information Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 45 LMK01801 SNAS573A – JANUARY 2012 – REVISED APRIL 2013 www.ti.com Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Original (April 2013) to Revision A • 46 Changed layout of National Data Sheet to TI format Page .......................................................................... Application Information 45 Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: LMK01801 PACKAGE OPTION ADDENDUM www.ti.com 19-Apr-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (°C) Top-Side Markings (3) (4) LMK01801BISQ/NOPB ACTIVE WQFN RHS 48 1000 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 85 K01801BI LMK01801BISQE/NOPB ACTIVE WQFN RHS 48 250 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 85 K01801BI LMK01801BISQX/NOPB ACTIVE WQFN RHS 48 2500 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 85 K01801BI (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) Multiple Top-Side Markings will be inside parentheses. Only one Top-Side Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Top-Side Marking for that device. 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Addendum-Page 1 Samples PACKAGE MATERIALS INFORMATION www.ti.com 24-Apr-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing LMK01801BISQ/NOPB WQFN RHS 48 LMK01801BISQE/NOPB WQFN RHS LMK01801BISQX/NOPB WQFN RHS SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 1000 330.0 16.4 7.3 7.3 1.3 12.0 16.0 Q1 48 250 178.0 16.4 7.3 7.3 1.3 12.0 16.0 Q1 48 2500 330.0 16.4 7.3 7.3 1.3 12.0 16.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 24-Apr-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMK01801BISQ/NOPB WQFN RHS 48 1000 367.0 367.0 38.0 LMK01801BISQE/NOPB WQFN RHS 48 250 213.0 191.0 55.0 LMK01801BISQX/NOPB WQFN RHS 48 2500 367.0 367.0 38.0 Pack Materials-Page 2 MECHANICAL DATA RHS0048A SQA48A (Rev B) www.ti.com IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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