LMK02000 Precision Clock Conditioner with Integrated PLL General Description Features The LMK02000 precision clock conditioner combines the functions of jitter cleaning/reconditioning, multiplication, and distribution of a reference clock. The device integrates a high performance Integer-N Phase Locked Loop (PLL), three LVDS, and five LVPECL clock output distribution blocks. Each clock distribution block includes a programmable divider, a phase synchronization circuit, a programmable delay, a clock output mux, and an LVDS or LVPECL output buffer. This allows multiple integer-related and phase-adjusted copies of the reference to be distributed to eight system components. The clock conditioner comes in a 48-pin LLP package and is footprint compatible with other clocking devices in the same family. ■ 20 fs additive jitter ■ Integrated Integer-N PLL with outstanding normalized ■ ■ ■ ■ ■ ■ phase noise contribution of -224 dBc/Hz Clock output frequency range of 1 to 800 MHz 3 LVDS and 5 LVPECL clock outputs Dedicated divider and delay blocks on each clock output Pin compatible family of clocking devices 3.15 to 3.45 V operation Package: 48 pin LLP (7.0 x 7.0 x 0.8 mm) Target Applications ■ ■ ■ ■ ■ ■ Data Converter Clocking Networking, SONET/SDH, DSLAM Wireless Infrastructure Medical Test and Measurement Military / Aerospace Functional Block Diagram 20216501 TRI-STATE® is a registered trademark of National Semiconductor Corporation. © 2007 National Semiconductor Corporation 202165 www.national.com LMK02000 Precision Clock Conditioner with Integrated PLL September 2007 LMK02000 Connection Diagram 48-Pin LLP Package 20216502 www.national.com 2 LMK02000 Pin Descriptions Pin # Pin Name I/O 1, 25 GND - Ground 2, 7 NC - No Connection to these pins - Power Supply 3, 8, 13, 16, 19, 22, 26, Vcc1, Vcc2, Vcc3, Vcc4, Vcc5, Vcc6, Vcc7, 30, 31, 33, 37, 40, 43, 46 Vcc8, Vcc9, Vcc10, Vcc11, Vcc12, Vcc13, Vcc14 Description 4 CLKuWire I MICROWIRE Clock Input 5 DATAuWire I MICROWIRE Data Input 6 LEuWire I MICROWIRE Latch Enable Input 9, 10 LDObyp1, LDObyp2 - LDO Bypass 11 GOE I Global Output Enable 12 LD O Lock Detect and Test Output 14, 15 CLKout0, CLKout0* O LVDS Clock Output 0 17, 18 CLKout1, CLKout1* O LVDS Clock Output 1 20, 21 CLKout2, CLKout2* O LVDS Clock Output 2 23, 24 CLKout3, CLKout3* O LVPECL Clock Output 3 27 SYNC* I Global Clock Output Synchronization 28, 29 OSCin, OSCin* I Oscillator Clock Input; Must be AC coupled 32 CPout O Charge Pump Output 34, 35 Fin, Fin* I Frequency Input; Must be AC coupled 36 Bias I Bias Bypass 38, 39 CLKout4, CLKout4* O LVPECL Clock Output 4 41, 42 CLKout5, CLKout5* O LVPECL Clock Output 5 44, 45 CLKout6, CLKout6* O LVPECL Clock Output 6 47, 48 CLKout7, CLKout7* O LVPECL Clock Output 7 DAP DAP - Die Attach Pad is Ground 3 www.national.com LMK02000 Absolute Maximum Ratings (Notes 1, 2) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Parameter Power Supply Voltage Input Voltage Symbol VCC Ratings Units -0.3 to 3.6 V VIN -0.3 to (VCC + 0.3) V TSTG -65 to 150 °C Lead Temperature (solder 4 s) TL +260 °C Junction Temperature TJ 125 °C Storage Temperature Range Recommended Operating Conditions Symbol TA Min Typ Max Units Ambient Temperature Parameter -40 25 85 °C Power Supply Voltage VCC 3.15 3.3 3.45 V Note 1: "Absolute Maximum Ratings" indicate limits beyond which damage to the device may occur, including inoperability and degradation of device reliability and/or performance. Functional operation of the device and/or non-degradation at the Absolute Maximum Ratings or other conditions beyond those indicated in the Recommended Operating Conditions is not implied. The Recommended Operating Conditions indicate conditions at which the device is functional and the device should not be operated beyond such conditions. Note 2: This device is a high performance integrated circuit with ESD handling precautions. Handling of this device should only be done at ESD protected work stations. The device is rated to a HBM-ESD of > 2 kV, a MM-ESD of > 200 V, and a CDM-ESD of > 1.2 kV. Package Thermal Resistance Package θJA θJ-PAD (Thermal Pad) 48-Lead LLP (Note 3) 27.4° C/W 5.8° C/W Note 3: Specification assumes 16 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 LLP. It is recommended that the maximum number of vias be used in the board layout. Electrical Characteristics (Note 4) (3.15 V ≤ Vcc ≤ 3.45 V, -40 °C ≤ TA ≤ 85 °C, Differential Inputs/Outputs; except as specified. Typical values represent most likely parametric norms at Vcc = 3.3 V, TA = 25 °C, and at the Recommended Operation Conditions at the time of product characterization and are not guaranteed). Symbol Parameter Conditions Min Typ Max Units Current Consumption ICC ICCPD Entire device; CLKout0 & CLKout4 enabled in Bypass Mode Power Supply Current (Note 5) Power Down Current 145.8 mA Entire device; All Outputs Off (no emitter resistors placed) 70 POWERDOWN = 1 1 mA Reference Oscillator fOSCin square Reference Oscillator Input Frequency Range for Square Wave VOSCinsquare Square Wave Input Voltage for OSCin and OSCin* fFin Frequency Input Frequency Range SLEWFin Frequency Input Slew Rate DUTYFin Frequency Input Duty Cycle PFin Input Power Range for Fin or Fin* 1 200 MHz 0.2 1.6 Vpp 1 800 MHz AC coupled; Differential (VOD) Frequency Input www.national.com (Notes 6, 10) 0.5 40 60 % AC coupled -13 8 dBm 4 V/ns Parameter Conditions Min Typ Max Units 40 MHz PLL fCOMP ISRCECPout Phase Detector Frequency Charge Pump Source Current VCPout = Vcc/2, PLL_CP_GAIN = 1x 100 VCPout = Vcc/2, PLL_CP_GAIN = 4x 400 VCPout = Vcc/2, PLL_CP_GAIN = 16x 1600 VCPout = Vcc/2, PLL_CP_GAIN = 32x 3200 VCPout = Vcc/2, PLL_CP_GAIN = 1x -100 VCPout = Vcc/2, PLL_CP_GAIN = 4x -400 VCPout = Vcc/2, PLL_CP_GAIN = 16x -1600 VCPout = Vcc/2, PLL_CP_GAIN = 32x -3200 µA μA ISINKCPout Charge Pump Sink Current ICPoutTRI Charge Pump TRI-STATE® Current 0.5 V < VCPout < Vcc - 0.5 V 2 ICPout%MIS Magnitude of Charge Pump Sink vs. Source Current Mismatch VCPout = Vcc / 2 TA = 25°C 3 % 0.5 V < VCPout < Vcc - 0.5 V TA = 25°C 4 % 4 % Magnitude of Charge Pump ICPoutVTUNE Current vs. Charge Pump Voltage Variation ICPoutTEMP Magnitude of Charge Pump Current vs. Temperature Variation PN10kHz PLL 1/f Noise at 10 kHz Offset (Note 7) Normalized to 1 GHz Output Frequency PLL_CP_GAIN = 1x -117 PLL_CP_GAIN = 32x -122 PN1Hz Normalized Phase Noise Contribution (Note 8) PLL_CP_GAIN = 1x -219 PLL_CP_GAIN = 32x -224 10 nA dBc/Hz dBc/Hz Clock Distribution Section (Note 9) - LVDS Clock Outputs (CLKout0 to CLKout2) JitterADD Additive RMS Jitter (Note 9) RL = 100 Ω Distribution Path = 800 MHz Bandwidth = 12 kHz to 20 MHz CLKoutX_MUX = Bypass 20 CLKoutX_MUX = Divided CLKoutX_DIV = 4 75 fs tSKEW CLKoutX to CLKoutY (Note 10) Equal loading and identical clock configuration RL = 100 Ω -30 ±4 30 ps VOD Differential Output Voltage RL = 100 Ω 250 350 450 mV ΔVOD Change in magnitude of VOD for complementary output states RL = 100 Ω -50 50 mV VOS Output Offset Voltage RL = 100 Ω 1.070 1.370 V ΔVOS Change in magnitude of VOS for complementary output states RL = 100 Ω -35 35 mV ISA ISB Clock Output Short Circuit Current single ended Single ended outputs shorted to GND -24 24 mA ISAB Clock Output Short Circuit Current differential Complementary outputs tied together -12 12 mA 5 1.25 www.national.com LMK02000 Symbol LMK02000 Symbol Parameter Conditions Min Typ Max Units Clock Distribution Section (Note 9) - LVPECL Clock Outputs (CLKout3 to CLKout7) JitterADD RL = 100 Ω Distribution Path = 800 MHz Bandwidth = 12 kHz to 20 MHz Additive RMS Jitter (Note 9) tSKEW CLKoutX to CLKoutY (Note 10) VOH Output High Voltage VOL Output Low Voltage VOD Differential Output Voltage CLKoutX_MUX = Bypass 20 CLKoutX_MUX = Divided CLKoutX_DIV = 4 75 Equal loading and identical clock configuration Termination = 50 Ω to Vcc - 2 V fs -30 Termination = 50 Ω to Vcc - 2 V 660 ±3 30 ps Vcc 0.98 V Vcc 1.8 V 810 965 mV Vcc V 0.8 V Digital LVTTL Interfaces (Note 11) VIH High-Level Input Voltage VIL Low-Level Input Voltage IIH High-Level Input Current VIH = Vcc -5.0 5.0 µA IIL Low-Level Input Current VIL = 0 -40.0 5.0 µA VOH High-Level Output Voltage IOH = +500 µA Vcc 0.4 VOL Low-Level Output Voltage 2.0 IOL = -500 µA V 0.4 V Vcc V 0.4 V Digital MICROWIRE Interfaces (Note 12) VIH High-Level Input Voltage VIL Low-Level Input Voltage IIH IIL 1.6 High-Level Input Current VIH = Vcc -5.0 5.0 µA Low-Level Input Current VIL = 0 -5.0 5.0 µA MICROWIRE Timing tCS Data to Clock Set Up Time See Data Input Timing 25 ns tCH Data to Clock Hold Time See Data Input Timing 8 ns tCWH Clock Pulse Width High See Data Input Timing 25 ns tCWL Clock Pulse Width Low See Data Input Timing 25 ns tES Clock to Enable Set Up Time See Data Input Timing 25 ns tCES Enable to Clock Set Up Time See Data Input Timing 25 ns tEWH Enable Pulse Width High See Data Input Timing 25 ns Note 4: The Electrical Characteristics tables list guaranteed specifications under the listed Recommended Operating Conditions except as otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and are not guaranteed. Note 5: See 3.4 for more current consumption / power dissipation calculation information. Note 6: For all frequencies the slew rate, SLEWFin, is measured between 20% and 80%. Note 7: A specification in modeling PLL in-band phase noise is the 1/f flicker noise, LPLL_flicker(f), which is dominant close to the carrier. Flicker noise has a 10 dB/decade slope. PN10kHz is normalized to a 10 kHz offset and a 1 GHz carrier frequency. PN10kHz = LPLL_flicker(10 kHz) - 20log(Fout / 1 GHz), where LPLL_flicker (f) is the single side band phase noise of only the flicker noise's contribution to total noise, L(f). To measure LPLL_flicker(f) it is important to be on the 10 dB/decade slope close to the carrier. A high phase detector frequency and a clean crystal are important to isolating this noise source from the total phase noise, L(f). LPLL_flicker (f) can be masked by the reference oscillator performance if a low power or noisy source is used. The total PLL inband phase noise performance is the sum of LPLL_flicker(f) and LPLL_flat(f). Note 8: A specification in modeling PLL in-band phase noise is the Normalized Phase Noise Contribution, LPLL_flat(f), of the PLL and is defined as PN1Hz = LPLL_flat(f) – 20log(N) – 10log(fCOMP). LPLL_flat(f) is the single side band phase noise measured at an offset frequency, f, in a 1 Hz Bandwidth and fCOMP is the phase detector frequency of the synthesizer. LPLL_flat(f) contributes to the total noise, L(f). To measure LPLL_flat(f) the offset frequency, f, must be chosen sufficiently smaller then the loop bandwidth of the PLL, and yet large enough to avoid a substantial noise contribution from the reference and flicker noise. LPLL_flat(f) can be masked by the reference oscillator performance if a low power or noisy source is used. Note 9: The Clock Distribution Section includes all parts of the device except the PLL section. Typical Additive Jitter specifications apply to the clock distribution section only. Note 10: Specification is guaranteed by characterization and is not tested in production. Note 11: Applies to GOE, LD, and SYNC*. www.national.com 6 LMK02000 Note 12: Applies to CLKuWire, DATAuWire, and LEuWire. Serial Data Timing Diagram 20216503 Data bits set on the DATAuWire signal are clocked into a shift register, MSB first, on each rising edge of the CLKuWire signal. On the rising edge of the LEuWire signal, the data is sent from the shift register to the addressed register determined by the LSB bits. After the programming is complete the CLKuWire, DATAuWire, and LEuWire signals should be returned to a low state. 7 www.national.com LMK02000 Charge Pump Current Specification Definitions 20216531 I1 = Charge Pump Sink Current at VCPout = Vcc - ΔV I2 = Charge Pump Sink Current at VCPout = Vcc/2 I3 = Charge Pump Sink Current at VCPout = ΔV I4 = Charge Pump Source Current at VCPout = Vcc - ΔV I5 = Charge Pump Source Current at VCPout = Vcc/2 I6 = Charge Pump Source Current at VCPout = ΔV ΔV = Voltage offset from the positive and negative supply rails. Defined to be 0.5 V for this device. Charge Pump Output Current Magnitude Variation vs. Charge Pump Output Voltage 20216532 Charge Pump Sink Current vs. Charge Pump Output Source Current Mismatch 20216533 Charge Pump Output Current Magnitude Variation vs. Temperature 20216534 www.national.com 8 The LMK02000 precision clock conditioner combines the functions of jitter cleaning/reconditioning, multiplication, and distribution of a reference clock. The device integrates a high performance Integer-N Phase Locked Loop (PLL), three LVDS, and five LVPECL clock output distribution blocks. Each clock distribution block includes a programmable divider, a phase synchronization circuit, a programmable delay, a clock output mux, and an LVDS or LVPECL output buffer. This allows multiple integer-related and phase-adjusted copies of the reference to be distributed to eight system components. The clock conditioner comes in a 48-pin LLP package and is footprint compatible with other clocking devices in the same family. SYNC* Timing Diagram 1.1 BIAS PIN To properly use the device, bypass Bias (pin 36) with a low leakage 1 µF capacitor connected to Vcc. This is important for low noise performance. 20216504 The SYNC* pin provides an internal pull-up resistor as shown on the functional block diagram. If the SYNC* pin is not terminated externally the clock outputs will operate normally. If the SYNC* function is not used, clock output synchronization is not guaranteed. 1.2 LDO BYPASS To properly use the device, bypass LDObyp1 (pin 9) with a 10 µF capacitor and LDObyp2 (pin 10) with a 0.1 µF capacitor. 1.8 CLKout OUTPUT STATES Each clock output may be individually enabled with the CLKoutX_EN bits. Each individual output enable control bit is gated with the Global Output Enable input pin (GOE) and the Global Output Enable bit (EN_CLKout_Global). All clock outputs can be disabled simultaneously if the GOE pin is pulled low by an external signal or EN_CLKout_Global is set to 0. 1.3 OSCILLATOR INPUT PORT (OSCin, OSCin*) The purpose of OSCin is to provide the PLL with a reference signal. The OSCin port must be AC coupled, refer to the System Level Diagram in the Application Information section. The OSCin port may be driven single endedly by AC grounding OSCin* with a 0.1 µF capacitor. 1.4 FREQUENCY INPUT PORT (Fin, Fin*) The purpose of Fin is to provide the PLL with a feedback signal from an external oscillator. The Fin port may be driven single endedly by AC grounding Fin*. 1.5 CLKout DELAYS Each individual clock output includes a delay adjustment. Clock output delay registers (CLKoutX_DLY) support a 150 ps step size and range from 0 to 2250 ps of total delay. CLKoutX _EN bit EN_CLKout _Global bit GOE pin Clock X Output State 1 1 Low Low Don't care 0 Don't care Off 0 Don't care Don't care Off 1 High / No Connect Enabled 1 When an LVDS output is in the Off state, the outputs are at a voltage of approximately 1.5 volts. When an LVPECL output is in the Off state, the outputs are at a voltage of approximately 1 volt. 1.6 LVDS/LVPECL OUTPUTS Each LVDS or LVPECL output may be disabled individually by programming the CLKoutX_EN bits. All the outputs may be disabled simultaneously by pulling the GOE pin low or programming EN_CLKout_Global to 0. 1.9 GLOBAL OUTPUT ENABLE AND LOCK DETECT The GOE pin provides an internal pull-up resistor. If it is not terminated externally, the clock output states are determined by the Clock Output Enable bits (CLKoutX_EN) and the EN_CLKout_Global bit. By programming the PLL_MUX register to Digital Lock Detect Active High (See 2.5.2), the Lock Detect (LD) pin can be connected to the GOE pin in which case all outputs are set low automatically if the synthesizer is not locked. 1.7 GLOBAL CLOCK OUTPUT SYNCHRONIZATION The SYNC* pin synchronizes the clock outputs. When the SYNC* pin is held in a logic low state, the divided outputs are also held in a logic low state. When the SYNC* pin goes high, the divided clock outputs are activated and will transition to a high state simultaneously. Clocks in the bypassed state are not affected by SYNC* and are always synchronized with the divided outputs. The SYNC* pin must be held low for greater than one clock cycle of the Frequency Input port, also known as the distribution path. Once this low event has been registered, the outputs will not reflect the low state for four more cycles. Similarly once the SYNC* pin becomes high, the outputs will not simultaneously transition high until four more distribution path clock cycles have passed. See the timing diagram below for further detail. In the timing diagram below the clocks are pro- 1.10 POWER ON RESET When supply voltage to the device increases monotonically from ground to Vcc, the power on reset circuit sets all registers to their default values, see 2.3.1 for more information on default register values. Voltage should be applied to all Vcc pins simultaneously. 9 www.national.com LMK02000 grammed as CLKout0_MUX = Bypassed, CLKout1_MUX = Divided, CLKout1_DIV = 2, CLKout2_MUX = Divided, and CLKout2_DIV = 4. 1.0 Functional Description LMK02000 2.0 General Programming Information The LMK02000 device is programmed using several 32-bit registers which control the device's operation. The registers consist of a data field and an address field. The last 4 register bits, ADDR[3:0] form the address field. The remaining 28 bits form the data field DATA[27:0]. During programming, LEuWire is low and serial data is clocked in on the rising edge of clock (MSB first). When LEuWire goes high, data is transferred to the register bank selected by the address field. Only registers R0 to R7, R11, R14, and R15 need to be programmed for proper device operation. It is required to program register R14. 2.1 RECOMMENDED PROGRAMMING SEQUENCE The recommended programming sequence involves programming R0 with the reset bit set (RESET = 1) to ensure the device is in a default state. It is not necessary to program R0 again, but if R0 is programmed again, the reset bit is programmed clear (RESET = 0). Registers are programmed in order with R15 being the last register programmed. An example programming sequence is shown below. • Program R0 with the reset bit set (RESET = 1). This ensures the device is in a default state. When the reset bit is set in R0, the other R0 bits are ignored. — If R0 is programmed again, the reset bit is programmed clear (RESET = 0). • Program R0 to R7 as necessary with desired clocks with appropriate enable, mux, divider, and delay settings. • Program R11 with DIV4 setting if necessary. • Program R14 with global clock output bit, power down setting, PLL mux setting, and PLL R divider. It is required to program register R14. — R14 must be programmed in accordance with the register map as shown in the register map (see 2.2). • Program R15 with PLL charge pump gain, and PLL N divider. www.national.com 10 www.national.com 0 0 R6 R7 0 R5 R2 0 R1 R4 0 R0 0 0 Register R3 0 RESET 0 0 0 0 0 0 0 30 31 0 0 0 0 0 0 0 0 29 0 0 0 0 0 0 0 0 28 0 0 0 0 0 0 0 0 27 0 0 0 0 0 0 0 0 26 0 0 0 0 0 0 0 0 25 0 0 0 0 0 0 0 0 24 0 0 0 0 0 0 0 0 23 0 0 0 0 0 0 0 0 22 0 0 0 0 0 0 0 0 21 0 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 0 19 17 CLKout7 _MUX [1:0] CLKout6 _MUX [1:0] CLKout5 _MUX [1:0] CLKout4 _MUX [1:0] CLKout3 _MUX [1:0] CLKout2 _MUX [1:0] CLKout1 _MUX [1:0] CLKout0 _MUX [1:0] Data [27:0] 18 16 CLKout7_EN CLKout6_EN CLKout5_EN CLKout4_EN CLKout3_EN CLKout2_EN CLKout1_EN CLKout0_EN 2.2 LMK02000 REGISTER MAP 15 14 13 11 CLKout7_DIV [7:0] CLKout6_DIV [7:0] CLKout5_DIV [7:0] CLKout4_DIV [7:0] CLKout3_DIV [7:0] CLKout2_DIV [7:0] CLKout1_DIV [7:0] CLKout0_DIV [7:0] 12 10 9 8 7 5 CLKout7_DLY [3:0] CLKout6_DLY [3:0] CLKout5_DLY [3:0] CLKout4_DLY [3:0] CLKout3_DLY [3:0] CLKout2_DLY [3:0] CLKout1_DLY [3:0] CLKout0_DLY [3:0] 6 4 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 A2 A3 0 2 3 1 1 0 0 1 1 0 0 A1 1 1 0 1 0 1 0 1 0 A0 0 LMK02000 11 www.national.com 12 1 0 0 0 PLL_ CP_ GAIN [1:0] R15 0 R14 0 0 Register R11 0 0 0 0 0 0 0 24 0 25 0 26 EN_CLKout_Global 27 POWERDOWN 28 TRI-STATE 29 PLL_CP_POL 30 31 0 0 1 PLL_MUX [3:0] 21 22 23 0 20 0 19 0 18 0 16 PLL_N [17:0] 1 17 0 0 13 PLL_R [11:0] 14 15 DIV4 0 12 0 11 0 10 0 9 0 8 0 0 0 7 0 0 0 6 0 0 0 5 0 0 0 4 1 1 1 3 1 1 0 2 1 1 1 1 1 0 1 0 LMK02000 Bit Name Default Bit Value 2.3.1 RESET Bit -- R0 only This bit is only in register R0. The use of this bit is optional and it should be set to '0' if not used. Setting this bit to a '1' forces all registers to their power on reset condition and therefore automatically clears this bit. If this bit is set, all other R0 bits are ignored and R0 needs to be programmed again if used with its proper values and RESET = 0. Bit State Bit Description Register Bit Location RESET 0 No reset, normal operation Reset to power on defaults CLKoutX_MUX 0 Bypassed CLKoutX mux mode CLKoutX_EN 0 Disabled CLKoutX enable CLKoutX_DIV 1 Divide by 2 CLKoutX clock divide CLKoutX_DLY 0 0 ps CLKoutX clock delay DIV4 0 PDF ≤ 20 MHz Phase Detector Frequency EN_CLKout_Global 1 Normal - CLKouts normal Global clock output enable 27 POWERDOWN 0 Normal - Device active Device power down 26 PLL_CP_TRI 0 Normal - PLL active TRI-STATE PLL charge pump PLL_CP_POL 0 Negative Polarity CP Polarity of charge pump PLL_MUX 0 Disabled Multiplexer control for LD pin 23:20 PLL_R 10 R divider = 10 PLL R divide value 19:8 0 100 uA Charge pump current N divider = 760 PLL N divide value PLL_CP_GAIN PLL_N 760 2.3.2 CLKoutX_MUX[1:0] -- Clock Output Multiplexers These bits control the Clock Output Multiplexer for each clock output. Changing between the different modes changes the blocks in the signal path and therefore incurs a delay relative to the bypass mode. The different MUX modes and associated delays are listed below. 13 R0 31 18:17 16 R0 to R7 15:8 7:4 R11 15 25 R14 R15 24 31:30 25:8 CLKoutX_MUX [1:0] Mode Added Delay Relative to Bypass Mode 0 Bypassed (default) 0 ps 1 Divided 100 ps 2 Delayed 400 ps (In addition to the programmed delay) 3 Divided and Delayed 500 ps (In addition to the programmed delay) www.national.com LMK02000 2.3 REGISTER R0 to R7 Registers R0 through R7 control the eight clock outputs. Register R0 controls CLKout0, Register R1 controls CLKout1, and so on. There is one additional bit in register R0 called RESET. Aside from this, the functions of these bits are identical. The X in CLKoutX_MUX, CLKoutX_DIV, CLKoutX_DLY, and CLKoutX_EN denote the actual clock output which may be from 0 to 7. LMK02000 2.3.3 CLKoutX_DIV[7:0] -- Clock Output Dividers These bits control the clock output divider value. In order for these dividers to be active, the respective CLKoutX_MUX (See 2.3.2) bit must be set to either "Divided" or "Divided and Delayed" mode. After all the dividers are programed, the SYNC* pin must be used to ensure that all edges of the clock outputs are aligned (See 1.7). By adding the divider block to the output path a fixed delay of approximately 100 ps is incurred. The actual Clock Output Divide value is twice the binary value programmed as listed in the table below. CLKoutX_DIV[7:0] 0 0 0 0 0 0 0 Invalid 0 0 0 0 0 0 0 1 2 (default) 0 0 0 0 0 0 1 0 4 0 0 0 0 0 0 1 1 6 0 0 0 0 0 1 0 0 8 0 0 0 0 0 1 0 1 10 . . . . . . . . ... 1 1 1 1 1 1 1 1 510 Delay (ps) 0 0 (default) 1 150 2 300 3 450 4 600 5 750 www.national.com 6 900 7 1050 8 1200 14 2100 15 2250 CLKoutX_EN bit 0 Conditions CLKoutX State EN_CLKout_Global Disabled (default) bit = 1 GOE pin = High / No Enabled Connect 1 1 2.4 REGISTER R11 This register only has one bit and only needs to be programmed in the case that the phase detector frequency is greater than 20 MHz and digital lock detect is used. Otherwise, it is automatically defaulted to the correct values. 2.4.1 DIV4 This bit divides the frequency presented to the digital lock detect circuitry by 4. It is necessary to get a reliable output from the digital lock detect output in the case of a phase detector frequency greater than 20 MHz. 2.3.4 CLKoutX_DLY[3:0] -- Clock Output Delays These bits control the delay stages for each clock output. In order for these delays to be active, the respective CLKoutX_MUX (See 2.3.2) bit must be set to either "Delayed" or "Divided and Delayed" mode. By adding the delay block to the output path a fixed delay of approximately 400 ps is incurred in addition to the delay shown in the table below. CLKoutX_DLY[3:0] Delay (ps) 2.3.5 CLKoutX_EN bit -- Clock Output Enables These bits control whether an individual clock output is enabled or not. If the EN_CLKout_Global bit (See 2.5.4) is set to zero or if GOE pin is held low, all CLKoutX_EN bit states will be ignored and all clock outputs will be disabled. See 1.8 for more information on CLKout states. Clock Output Divider value 0 CLKoutX_DLY[3:0] DIV4 Digital Lock Detect Circuitry Mode 0 Not divided; Phase detector frequency ≤ 20 MHz (default) 1 Divided by 4; Phase detector frequency > 20 MHz 2.5 REGISTER R14 The LMK02000 requires register R14 to be programmed as shown in the register map (see 2.2). 2.5.1 PLL_R[11:0] -- R Divider Value These bits program the PLL R Divider and are programmed in binary fashion. PLL_R[11:0] PLL R Divide Value 9 1350 0 0 0 0 0 0 0 0 0 0 0 0 Invalid 10 1500 0 0 0 0 0 0 0 0 0 0 0 1 1 11 1650 0 0 0 0 0 0 0 0 0 0 1 0 2 12 1800 . . . . . . . . . . . . ... 13 1950 0 0 0 0 0 0 0 0 1 0 1 0 10 (default) . . . . . . . . . . . . ... 1 1 1 1 1 1 1 1 1 1 1 1 4095 14 PLL_CP_TRI PLL Charge Pump PLL_MUX[3:0] Output Type LD Pin Function 0 Normal operation (default) 0 Hi-Z Disabled (default) 1 TRI-STATE 1 Push-Pull Logic High 2 Push-Pull Logic Low 3 Push-Pull Digital Lock Detect (Active High) 4 Push-Pull Digital Lock Detect (Active Low) 5 Push-Pull Analog Lock Detect PLL_CP_POL PLL Charge Pump Polarity 0 Negative (default) 6 Open Drain NMOS Analog Lock Detect 1 Positive 7 Open Drain PMOS Analog Lock Detect 8 2.5.6 PLL_CP_POLBbit -- PLL Charge Pump Polarity This bit sets the polarity of the charge pump to either negative or positive. A negative charge pump is used with a VCO or VCXO which decreases frequency with increasing tuning voltage. A positive charge pump is used with a VCO or VCXO which increases frequency with increasing tuning voltage. 2.6 Register R15 2.6.1 PLL_N[17:0] -- PLL N Divider These bits program the divide value for the PLL N Divider. The PLL N Divider precedes the PLL phase detector. The VCO or VCXO frequency is calculated as, fVCO = fOSCin × PLL N Divider / PLL R Divider. Since the PLL N divider is a pure binary counter, there are no illegal divide values for PLL_N [17:0] except for 0. Invalid 9 Push-Pull 10 N Divider Output/2 (50% Duty Cycle) Invalid 11 Push-Pull 12 to 15 R Divider Output/2 (50% Duty Cycle) 2.5.3 POWERDOWN Bit -- Device Power Down This bit can power down the device. Enabling this bit powers down the entire device and all blocks, regardless of the state of any of the other bits or pins. POWERDOWN bit Mode 0 Normal Operation (default) 1 Entire Device Powered Down 2.5.4 EN_CLKout_Global Bit -- Global Clock Output Enable This bit overrides the individual CLKoutX_EN bits (See 2.3.5). When this bit is set to 0, all clock outputs are disabled, regardless of the state of any of the other bits or pins. See 1.8 for more information on CLKout states. EN_CLKout_Global bit PLL_N[17:0] PLL N Divider Value 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Invalid Invalid All Off 1 Normal Operation (default) 1 . . . . . . . . . . . . . . . . . . ... 0 0 0 0 0 0 0 0 1 0 1 1 1 1 1 0 0 0 760 (default) . . . . . . . . . . . . . . . . . . ... 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 262143 2.6.2 PLL_CP_GAIN[1:0] -- PLL Charge Pump Gain These bits set the charge pump gain of the PLL. Clock Outputs 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 15 PLL_CP_GAIN[1:0] Charge Pump Gain 0 1x (default) 1 4x 2 16x 3 32x www.national.com LMK02000 2.5.5 PLL_CP_TRI Bit -- PLL Charge Pump TRI-STATE This bit sets the PLL charge pump TRI-STATE. 2.5.2 PLL_MUX[3:0] -- Multiplexer Control for LD Pin These bits set the output mode of the LD pin. The table below lists several different modes. LMK02000 3.0 Application Information 3.1 SYSTEM LEVEL DIAGRAM The following shows the LMK02000 in a typical application. In this setup the clock may be multiplied, reconditioned, and redistributed. 20216570 FIGURE 1. Typical Application 3.2 BIAS PIN To properly use the device, bypass Bias (pin 36) with a low leakage 1 µF capacitor connected to Vcc. This is important for low noise performance. www.national.com 3.3 LDO BYPASS To properly use the device, bypass LDObyp1 (pin 9) with a 10 µF capacitor and LDObyp2 (pin 10) with a 0.1 µF capacitor. 16 Table 3.4 - Block Current Consumption Current Consumption at 3.3 V (mA) Power Dissipated in device (mW) Power Dissipated in LVPECL emitter resistors (mW) 70 231 - Low clock buffer The low clock buffer is enabled anytime one of (internal) CLKout0 through CLKout3 are enabled 9 29.7 - High clock buffer The high clock buffer is enabled anytime one of (internal) the CLKout4 through CLKout7 are enabled 9 29.7 - LVDS output, bypass mode 17.8 58.7 - LVPECL output, bypass mode (includes 120 Ω emitter resistors) 40 72 60 LVPECL output, disabled mode (includes 120 Ω emitter resistors) 17.4 38.3 19.1 0 0 - Block Condition Entire device, core current All outputs off; No LVPECL emitter resistors connected Output buffers LVPECL output, disabled mode. No emitter resistors placed; open outputs Divide circuitry per output Divide enabled, divide = 2 5.3 17.5 - Divide enabled, divide > 2 8.5 28.0 - Delay circuitry per output Delay enabled, delay < 8 5.8 19.1 - Delay enabled, delay > 7 9.9 32.7 - Entire device CLKout0 & CLKout4 enabled in bypass mode 145.8 421.1 60 From Table 3.4 the current consumption can be calculated in any configuration. For example, the current for the entire device with 1 LVDS (CLKout0) & 1 LVPECL (CLKout4) output in bypass mode can be calculated by adding up the following blocks: core current, low clock buffer, high clock buffer, one LVDS output buffer current, and one LVPECL output buffer current. There will also be one LVPECL output drawing emitter current, but some of the power from the current draw is dissipated in the external 120 Ω resistors which doesn't add to the power dissipation budget for the device. If delays or divides are switched in, then the additional current for these stages needs to be added as well. For power dissipated by the device, the total current entering the device is 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. For example, in the case of 1 LVDS (CLKout0) & 1 LVPECL (CLKout4) operating at 3.3 volts, we calculate 3.3 V × (70 + 9 + 9 + 17.8 + 40) mA = 3.3 V × 145.8 mA = 481.1 mW. Because the LVPECL output (CLKout4) has the emitter resistors hooked up and the power dissipated by these resistors is 60 mW, the total device power dissipation is 481.1 mW - 60 mW = 421.1 mW. When the LVPECL output is active, ~1.9 V is the average voltage on each output as calculated from the LVPECL Voh & Vol typical specification. Therefore the power dissipated in each emitter resistor is approximately (1.9 V)2 / 120 Ω = 30 mW. When the LVPECL output is disabled, the emitter resistor voltage is ~1.07 V. Therefore the power dissipated in each emitter resistor is approximately (1.07 V)2 / 120 Ω = 9.5 mW. 3.5 THERMAL MANAGEMENT Power consumption of the LMK02000 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 the 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 land and via pattern is shown in Figure 2. More information on soldering LLP packages can be obtained at www.national.com. 17 www.national.com LMK02000 calculate estimated current consumption of the LMK02000. Unless otherwise noted Vcc = 3.3 V, TA = 25 °C. 3.4 CURRENT CONSUMPTION / POWER DISSIPATION CALCULATIONS Due to the myriad of possible configurations the following table serves to provide enough information to allow the user to LMK02000 20216573 FIGURE 2. To minimize junction temperature it is recommended that a simple heat sink be built into the PCB (if the ground plane layer is not exposed). This is done by including a copper area of about 2 square inches on the opposite side of the PCB from the device. This copper area may be plated or solder coated to prevent corrosion but should not have conformal coating (if www.national.com possible), which could provide thermal insulation. The vias shown in Figure 2 should connect these top and bottom copper layers and to the ground layer. These vias act as “heat pipes” to carry the thermal energy away from the device side of the board to where it can be more effectively dissipated. 18 LMK02000 Physical Dimensions inches (millimeters) unless otherwise noted Leadless Leadframe Package (Bottom View) 48 Pin LLP (SQA48A) Package Order Number Package Marking Packing LVDS Outputs LVPECL Outputs LMK02000ISQ LMK02000ISQX K02000 I 250 Unit Tape and Reel 3 5 K02000 I 2500 Unit Tape and Reel 3 5 19 www.national.com LMK02000 Precision Clock Conditioner with Integrated PLL Notes THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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