LMK01000 Family LMK01000 Family 1.6 GHz High Performance Clock Buffer, Divider, and Distributor General Description Features The LMK01000 family provides an easy way to divide and distribute high performance clock signals throughout the system. These devices provide best-in-class noise performance and are designed to be pin-to-pin and footprint compatible with LMK03000/LMK02000 family of precision clock conditioners. The LMK01000 family features two programmable clock inputs (CLKin0 and CLKin1) that allow the user to dynamically switch between different clock domains. Each device features 8 clock outputs with independently programmable dividers and delay adjustments. The outputs of the device can be easily synchronized by an external pin (SYNC*). Target Applications 30 fs additive jitter (100 Hz to 20 MHz) Dual clock inputs Programmable output channels (0 to 1600 MHz) External synchronization 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) Device LVDS Outputs LVPECL Outputs LMK01000 3 5 LMK01010 8 0 LMK01020 0 8 High performance Clock Distribution Wireless Infrastructure Medical Imaging Wired Communications Test and Measurement Military / Aerospace System Diagram 30042806 TRI-STATE(R) is a registered trademark of National Semiconductor Corporation. (c) 2009 National Semiconductor Corporation 300428 www.national.com LMK01000 Family 1.6 GHz High Performance Clock Buffer, Divider, and Distributor July 15, 2009 LMK01000 Family Functional Block Diagram 30042801 Connection Diagram 48-Pin LLP Package 30042802 www.national.com 2 Pin # Pin Name I/O 1, 25 GND - Ground 2, 7, 9,10, 32 NC - No Connect. Pin is not connected to the die. - 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 11 GOE I Global Output Enable 12 Test O This is an output pin used strictly for test purposes and should be not connected for normal operation. However, any load of an impedance of more than 1 k is acceptable. 14, 15 CLKout0, CLKout0* O Clock Output 0 17, 18 CLKout1, CLKout1* O Clock Output 1 20, 21 CLKout2, CLKout2* O Clock Output 2 23, 24 CLKout3, CLKout3* O Clock Output 3 27 SYNC* I Global Clock Output Synchronization 28, 29 CLKin0,CLKin0* I CLKin 0 Input; Must be AC coupled 34, 35 CLKin1, CLKin1* I CLKin 1 Input; Must be AC coupled 36 Bias I Bias Bypass 38, 39 CLKout4, CLKout4* O Clock Output 4 41, 42 CLKout5, CLKout5* O Clock Output 5 44, 45 CLKout6, CLKout6* O Clock Output 6 47, 48 CLKout7, CLKout7* O Clock Output 7 DAP DAP - Die Attach Pad should be connected to ground. The LMK01000 family is footprint compatible with the LMK03000/02000 family of devices. All CLKout pins are pin-to-pin compatible, and CLKin0 and CLKin1 are equivalent to OSCin and Fin, respectively. Device Configuration Information Output LMK01000 LMK01010 LMK01020 CLKout0 LVDS LVDS LVPECL CLKout1 LVDS LVDS LVPECL CLKout2 LVDS LVDS LVPECL CLKout3 LVPECL LVDS LVPECL CLKout4 LVPECL LVDS LVPECL CLKout5 LVPECL LVDS LVPECL CLKout6 LVPECL LVDS LVPECL CLKout7 LVPECL LVDS LVPECL 3 www.national.com LMK01000 Family Pin Descriptions LMK01000 Family Absolute Maximum Ratings (Note 1, Note 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 JA J-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 Power Supply Current (Note 5) Power Down Current All outputs enabled, no divide or delay ( CLKoutX_MUX = Bypassed ) LMK01000 271 LMK01010 160 LMK01020 338 Per channel, no divide or delay (CLKoutX_MUX = Bypassed ) LVDS 17.8 LVPECL (Includes Emitter Resistors) mA 40 POWERDOWN = 1 1 CLKin0, CLKin0*, CLKin1, CLKin1* fCLKin CLKin Frequency Range SLEWCLKin CLKin Frequency Input Slew Rate DUTYCLKin CLKin Frequency Input Duty Cycle PCLKin Input Power Range for CLKin or CLKin* www.national.com 1 1600 (Note 6, Note 8) 0.5 fCLKin 800 MHz 30 70 fCLKin > 800 MHz 40 60 AC coupled -13 5 4 MHz V/ns % dBm Parameter Conditions Min Typ Max Units Clock Distribution Section--Delays DelayCLKout Maximum Allowable Delay(Note 8) fCLKoutX 1 GHz (Delay is limited to maximum programmable value) 2250 ps fCLKoutX > 1 GHz (Delay is limited to 1/2 of a period) 0.5/ fCLKoutX Clock Distribution Section - Divides DivideCLKoutX Allowable divide range. (Note that 1 is fCLKinX 1300 MHz the only allowable odd divide value) 1300 MHz < f CLKinX 1600 MHz 1 510 1 2 n/a Clock Distribution Section - LVDS Clock Outputs JitterADD Additive RMS Jitter (Note 7) fCLKoutX = 200 MHz RL = 100 Bandwidth = fCLKoutX = 800 MHz 100 Hz to 20 MHz fCLKoutX = 1600 MHz Vboost = 1 80 30 fCLKoutX = 200 MHz -156 fCLKoutX = 800 MHz -153 fCLKoutX = 1600 MHz -148 Divider Noise Floor(Note 7) RL = 100 Vboost = 1 tSKEW CLKoutX to CLKoutY (Note 8) Equal loading and identical clock configuration RL = 100 VOD Differential Output Voltage (Note 9) VOD Change in magnitude of VOD for complementary output states RL = 100 -50 VOS Output Offset Voltage RL = 100 1.070 VOS Change in magnitude of VOS for complementary output states RL = 100 ISA ISB Clock Output Short Circuit Current single ended ISAB Clock Output Short Circuit Current differential Noise Floor Vboost=0 fs 25 dBc/Hz -30 4 30 250 350 450 Vboost=1 390 ps mV 50 mV 1.370 V -35 35 mV Single ended outputs shorted to GND -24 24 mA Complementary outputs tied together -12 12 mA 5 1.25 www.national.com LMK01000 Family Symbol LMK01000 Family Symbol Parameter Conditions Min Typ Max Units Clock Distribution Section - LVPECL Clock Outputs JitterADD Noise Floor Additive RMS Jitter(Note 7) Divider Noise Floor(Note 7) tSKEW CLKoutX to CLKoutY (Note 8) VOH Output High Voltage fCLKoutX = 200 MHz RL = 100 Bandwidth = fCLKoutX = 800 MHz 100 Hz to 20 MHz fCLKoutX = 1600 MHz Vboost = 1 RL = 100 Vboost = 1 65 25 fCLKoutX = 200 MHz -158 fCLKoutX = 800 MHz -154 fCLKoutX = 1600 MHz -148 Equal loading and identical clock configuration Termination = 50 to Vcc - 2 V fs 25 -30 Termination = 50 to Vcc - 2 V 3 dBc/Hz 30 ps Vcc 0.98 V Vcc 1.8 V VOL Output Low Voltage VOD Differential Output Voltage VIH High-Level Input Voltage VIL Low-Level Input Voltage 0.8 V IIH High-Level Input Current VIH = Vcc -5.0 5.0 A IIL Low-Level Input Current VIL = 0 -40.0 5.0 A Vcc 0.4 Vboost = 0 (Note 9) 660 Vboost = 1 810 965 865 mV Digital LVTTL Interfaces (Note 10) 2.0 VOH High-Level Output Voltage IOH = +500 A VOL Low-Level Output Voltage IOL = -500 A www.national.com 6 Vcc V V 0.4 V Parameter Conditions Min Typ Max Units Vcc V Digital MICROWIRE Interfaces (Note 11) VIH High-Level Input Voltage VIL Low-Level Input Voltage 0.4 V IIH High-Level Input Current VIH = Vcc -5.0 5.0 A IIL Low-Level Input Current VIL = 0 -5.0 5.0 A 1.6 MICROWIRE Timing tCS Data to Clock Set Up Time See Data Input Timing tCH Data to Clock Hold Time tCWH Clock Pulse Width High tCWL tES 25 ns See Data Input Timing 8 ns See Data Input Timing 25 ns Clock Pulse Width Low See Data Input Timing 25 ns 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 section 3.2 for more current consumption / power dissipation calculation information. Note 6: For all frequencies the slew rate, SLEWCLKin1, is measured between 20% and 80%. Note 7: The noise floor of the divider is measured as the far out phase noise of the divider. Typically this offset is 40 MHz, but for lower frequencies this measurement offset can be as low as 5 MHz due to measurement equipment limitations. If the delay is used, then use section 1.3. Note 8: Specification is guaranteed by characterization and is not tested in production. Note 9: See characterization plots to see how this parameter varies over frequency. Note 10: Applies to GOE, LD, and SYNC*. Note 11: Applies to CLKuWire, DATAuWire, and LEuWire. Serial Data Timing Diagram 30042803 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. The slew rate of CLKuWire, DatauWire, and LEuWire should be at least 30 V/s. 7 www.national.com LMK01000 Family Symbol LMK01000 Family Typical Performance Characteristics LVDS Differential Output Voltage (VOD) LVPECL Differential Output Voltage (VOD) 30042807 30042808 LVDS Output Noise Floor LVPECL Output Noise Floor 30042809 30042810 Delay Noise Floor (Adds to Output Noise Floor) 30042811 www.national.com 8 LMK01000 Family SYNC* Timing Diagram 1.0 Functional Description The LMK01000 family includes a programmable divider, a phase synchronization circuit, a programmable delay, a clock output mux, and an LVDS or LVPECL output buffer in each channel. This allows multiple integer-related and phase-adjusted copies of the reference to be distributed to up to eight system components. This family of devices comes in a 48-pin LLP package that is pin-to-pin and footprint compatible with other LMK02000/ LMK03000 family of clocking devices. 1.1 BIAS PIN To properly use the device, bypass Bias (pin 36) with a low leakage 1 F capacitor connected to Vcc. This is important for low noise performance. 30042804 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 CLKin0/CLKin0* and CLKin1/CLKin1 INPUT PORTS The device can be driven either by the CLKin0/CLKin0* or the CLKin1/CLKin1* pins. The choice of which one to use is software selectable. These input ports must be AC coupled. To drive these inputs in a single ended fashion, AC ground the complementary input. When choosing AC coupling capacitors for clock signals 0.1 F is a good starting point, but lower frequencies may require higher value capacitors while higher frequencies may use lower value capacitors. 1.6 CONNECTION TO LVDS OUTPUTS LMK01000 and LMK01010 LVDS outputs can be connected in AC or DC coupling configurations; however, in DC coupling configuration, proper conditions must be presented by the LVDS receiver. To ensure such conditions, we recommend the usage of LVDS receivers without fail-safe or internal input bias such as National Semiconductor's DS90LV110T. The LMK01000 family LVDS drivers provide the adequate DC bias for the LVDS receiver. We recommend AC coupling when using LVDS receivers with fail-safe or internal input bias. 1.3 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. When the delay is enabled it adds to the output noise floor; the total additive noise is 10(log( 10^(Output Noise Floor/10) + 10^ (Delay Noise Floor/10) ). Refer to the Typical Performance Characteristics plots for the Delay Noise Floor information. 1.7 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. 1.4 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. 1.5 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. When the SYNC* pin becomes high, the outputs will not simultaneously transition high until four more distribution path clock cycles have passed. See the SYNC* timing diagram for further detail. In the timing diagram below the clocks are programmed as CLKout0_MUX = Bypassed, CLKout1_MUX = Divided, CLKout1_DIV = 2, CLKout2_MUX = Divided, and CLKout2_DIV = 4. 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. 1.8 GLOBAL OUTPUT ENABLE 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. 1.9 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, which are specified in the General Programming Information section. Voltage should be applied to all Vcc pins simultaneously. 9 www.national.com LMK01000 Family 2.0 General Programming Information The LMK01000 family device is programmed using several 32-bit registers. 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 and R14 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). 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 R14 with global clock output bit, power down setting. -- R14 must be programmed in accordance with the register map as shown in the register map (See Section 2.2). www.national.com 10 11 0 0 0 R7 R9 R14 0 R4 0 0 R3 R6 0 R2 0 0 R1 R5 0 R0 1 0 0 0 0 0 0 0 0 30 31 RESET Register 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 CLKin _SELECT 0 0 0 0 0 0 0 0 27 28 29 2.2 Register Map EN_CLKout _Global 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 POWERDOWN 0 24 25 26 0 0 0 0 0 0 0 0 0 0 23 0 0 0 0 0 0 0 0 0 0 22 0 0 0 0 0 0 0 0 0 0 21 0 0 0 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 0 0 0 19 17 0 0 0 1 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 0 Vbo ost 0 0 15 0 0 14 0 1 13 11 0 0 0 1 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 0 0 10 0 1 9 0 0 8 0 0 7 5 0 0 0 0 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 0 0 4 1 1 0 0 0 0 0 0 0 1 0 1 1 1 1 0 0 0 0 A2 A3 0 2 3 1 0 1 1 0 0 1 1 0 0 A1 1 0 1 1 0 1 0 1 0 1 0 A0 0 LMK01000 Family CLKout0 CLKout1 CLKout2 CLKout3 CLKout4 CLKout5 CLKout6 CLKout7 _EN _EN _EN _EN _EN _EN _EN _EN www.national.com LMK01000 Family 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. 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. Default Register Settings after Power-on-Reset Bit Name Default Bit Value 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 7:4 CLKin_SELECT 0 CLKin1 Select CLKin0 or CLKin1 29 EN_CLKout_Global 1 Normal - CLKouts normal Global clock output enable POWERDOWN 0 Normal - Device active Device power down 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. Mode 0 Bypassed (default) 0 ps 1 Divided 100 ps Delayed 400 ps (In addition to the programmed delay) 2 3 Divided and Delayed 16 R0 to R7 15:8 R14 27 26 Clock Output Divider value 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 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 Section 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. Added Delay Relative to Bypassed Mode 500 ps (In addition to the programmed delay) 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 Section 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 Section 1.5). 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. www.national.com 31 18:17 CLKoutX_DIV[7:0] 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 Bypassed mode. The different MUX modes and associated delays are listed below. CLKoutX_MUX [1:0] R0 12 CLKoutX_DLY[3:0] Delay (ps) 0 0 (default) 1 150 2 300 3 450 4 600 5 750 6 900 7 1050 8 1200 9 1350 10 1500 11 1650 12 1800 13 1950 14 2100 15 2250 CLKoutX_EN bit 0 1 Conditions 2.5.1 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. CLKoutX State EN_CLKout_Global Disabled (default) bit = 1 GOE pin = High / No Enabled Connect 1 2.4 REGISTER R9 R9 only needs to be programmed if Vboost is set to 1. Program all other bits in R9 as indicated in register map (See Section 2.2) 0 1 fCLKoutX < 1300 MHz 1300 MHz fCLKoutX < 1500 MHz fCLKoutX 1600 MHz Insufficient voltage level for LVDS/LVPECL specifications, but saves current Voltage May overdrive LVPECL/ LVDS specifications, but noise floor is about 2-4 dB better and current consumption is increased Voltage is sufficient for LVDS/ LEVPECL specifications . Current consumption is increased, but noise floor is about the same. Normal Operation (default) 1 Entire Device Powered Down EN_CLKout_Global bit Clock Outputs 0 All Off 1 Normal Operation (default) 2.5.3 CLKin_SELECT Bit -- Device CLKin Select This bit determines which CLKin pin is used. 1500 MHz Recommended to hit voltage level specifications for LVPECL/LVDS Mode 0 2.5.2 EN_CLKout_Global Bit -- Global Clock Output Enable This bit overrides the individual CLKoutX_EN bits. When this bit is set to 0, all clock outputs are disabled, regardless of the state of any of the other bits or pins. 2.4.1 Vboost - Voltage Boost Bit Enabling this bit sets all clock outputs in voltage boost mode which increases the voltage at these outputs. This can improve the noise floor performance of the output, but also increases current consumption, and can cause the outputs to be too high to meet the LVPECL/LVDS specifications. Vboost bit POWERDOWN bit CLKin bit Mode 0 CLKin1 (default) 1 CLKin0 Insufficient voltage for LVDS/ LVPECL specifications , but still higher than when Vboost=0. Increased current consumption. 13 www.national.com LMK01000 Family 2.5 REGISTER R14 The LMK01000 family requires register R14 to be programmed as shown in the register map (See Section 2.2). 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 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. LMK01000 Family 3.0 Application Information 3.1 SYSTEM LEVEL DIAGRAM The following shows a typical application for a LMK01000 family device. In this setup the clock may be divided, skewed, and redistributed. 30042870 FIGURE 1. Typical Application www.national.com 14 Block Condition Core Current All outputs disabled. Includes input buffer currents. Current Consumption at 3.3 V (mA) Power Dissipated in device (mW) Power Dissipated in LVPECL emitter resistors (mW) 19 62.7 - Low clock buffer The low clock buffer is enabled anytime one of CLKout0 (internal) through CLKout3 are enabled 9 29.7 - High clock The high clock buffer is enabled anytime one of the CLKout4 buffer (internal) through CLKout7 are enabled 9 29.7 - 17.8 58.7 - LVPECL output, Bypassed mode (includes 120 emitter resistors) 40 72 60 LVPECL output, disabled mode (includes 120 emitter resistors) 17.4 38.3 19.1 0 0 - Additional current per channel LVPECL Output due to setting Vboost from 0 to 1. LVDS Output 0.5 1.65 - 1.5 5.0 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 LMK01000 CLKout0 & LMK01010 CLKout4 enabled in LMK01020 Bypassed mode 85.8 223.1 60 63.6 209.9 - 108 236.4 120 Entire device LMK01000 all outputs LMK01010 enabled with no delay and divide LMK01020 value of 2 323.8 768.5 300 212.8 702.3 - 390.4 808.3 480 LVDS output, Bypassed mode Output buffers LVPECL output, disabled mode. No emitter resistors placed; open outputs Vboost From the above table, the current can be calculated in any configuration. For example, the current for the entire device with 1 LVDS (CLKout0) & 1 LVPECL (CLKout4) output in Bypassed 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 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 for LMK01000, we calculate 3.3 V x (10 + 9 + 9 + 17.8 + 40) mA = 3.3 V x 85.8 mA = 283.1 mW. Because the LVPECL output (CLKout4) has the emitter resistors hooked up and the power dissipated by these resistors is 60 mW, the total power dissipation is 283.1 mW - 60 mW = 223.1 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 = 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 = 9.5 mW. 15 www.national.com LMK01000 Family 3.2 CURRENT CONSUMPTION / POWER DISSIPATION CALCULATIONS (Vcc = 3.3 V, TA = 25 C) LMK01000 Family lines are followed. Check the datasheet of the receiver or input being driven to determine the best termination and coupling method to be sure the receiver is biased at the optimum DC voltage (common mode voltage). For example, when driving the OSCin/OSCin* input of the LMK01000 family, OSCin/ OSCin* should be AC coupled because OSCin/ OSCin* biases the signal to the proper DC level, see Figure 1. This is only slightly different from the AC coupled cases described (See Section 3.4.2) because the DC blocking capacitors are placed between the termination and the OSCin/OSCin* pins, but the concept remains the same, which is the receiver (OSCin/ OSCin*) set the input to the optimum DC bias voltage (common mode voltage), not the driver. 3.3 THERMAL MANAGEMENT Power consumption of the LMK01000 family device 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 JA 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. 3.4.1 Termination for DC Coupled Differential Operation For DC coupled operation of an LVDS driver, terminate with 100 as close as possible to the LVDS receiver as shown in Figure 3. To ensure proper LVDS operation when DC coupling it is recommend to use LVDS receivers without fail-safe or internal input bias such as National Semiconductor's DS90LV110T. The LVDS driver will provide the DC bias level for the LVDS receiver. For operation with LMK01000 family LVDS drivers it is recommend to use AC coupling with LVDS receivers that have an internal DC bias voltage. Some failsafe circuitry will present a DC bias (common mode voltage) which will prevent the LVDS driver from working correctly. This precaution does not apply to the LVPECL drivers. 30042873 30042820 FIGURE 2. Recommended Land and Via Pattern FIGURE 3. Differential LVDS Operation, DC Coupling 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 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. For DC coupled operation of an LVPECL driver, terminate with 50 to Vcc - 2 V as shown in Figure 4. Alternatively terminate with a Thevenin equivalent circuit (120 resistor connected to Vcc and an 82 resistor connected to ground with the driver connected to the junction of the 120 and 82 resitors) as shown in Figure 5 for Vcc = 3.3 V. 3.4 TERMINATION AND USE OF CLOCK OUTPUTS 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. -- LVDS drivers are current drivers and require a closed current loop. -- LVPECL drivers are open emitter 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 a LVDS or LVPECL driver as long as the above guidewww.national.com 30042821 FIGURE 4. Differential LVPECL Operation, DC Coupling 16 30042822 FIGURE 5. Differential LVPECL Operation, DC Coupling, Thevenin Equivalent 30042823 FIGURE 6. Differential LVDS Operation, AC Coupling equivalent circuit (82 resistor connected to Vcc and a 120 resistor connected to ground with the driver connected to the junction of the 82 and 120 resistors) is a valid termination as shown in Figure 7 for Vcc = 3.3 V. Note: this Thevenin circuit is different from the DC coupled example in Figure 5. LVPECL drivers require a DC path to ground. When AC coupling an LVPECL signal use 120 emitter resistors close to the LVPECL driver to provide a DC path to ground as shown in Figure 10. 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 (common mode voltage) for LVPECL receivers is 2 V. A Thevenin 30042824 FIGURE 7. Differential LVPECL Operation, AC Coupling, Thevenin Equivalent It is possible to use an LVPECL driver as one or two separate 800 mV p-p signals. When DC coupling one of the LMK01000 family LVPECL drivers, the termination should still be 50 to Vcc - 2 V as shown in Figure 8. Again the Thevenin equivalent circuit (120 resistor connected to Vcc and an 82 resistor connected to ground with the driver connected to the junction 3.4.3 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. 17 www.national.com LMK01000 Family 3.4.2 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 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 6. LMK01000 Family of the 120 and 82 resistors) is a valid termination as shown in Figure 9 for Vcc = 3.3 V. 3.4.4 Conversion to LVCMOS Outputs To drive an LVCMOS input with an LMK01000 family LVDS or LVPECL output, an LVPECL/LVDS to LVCMOS converter such as National Semiconductor's DS90LV018A, DS90LV028A, DS90LV048A, etc. is required. For best noise performance, LVPECL provides a higher voltage swing into input of the converter. 3.5 OSCin INPUT In addition to LVDS and LVPECL inputs, OSCin can also be driven with a sine wave. The OSCin input can be driven single-ended or differentially with sine waves. These configurations are shown in Figure 11 and Figure 12. 30042825 FIGURE 8. Single-Ended LVPECL Operation, DC Coupling 30042828 FIGURE 11. Single-Ended Sine Wave Input 30042826 FIGURE 9. Single-Ended LVPECL Operation, DC Coupling, Thevenin Equivalent When AC coupling an LVPECL driver use a 120 emitter resistor to provide a DC path to ground and ensure a 50 termination with the proper DC bias level for the receiver. The typical DC bias voltage for LVPECL receivers is 2 V (See Section 3.4.1). If the other 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 V DC) is expected for safe and proper operation. The internal 50 termination the test equipment correctly terminates the LVPECL driver being measured as shown in Figure 10. When using only one LVPECL driver of a CLKoutX/CLKoutX* pair, be sure to properly terminated the unused driver. 30042829 FIGURE 12. Differential Sine Wave Input Figure 13 shows the recommended power level for sine wave operation for both differential and single-ended sources over frequency. The part will operate at power levels below the recommended power level, but as power decreases the PLL noise performance will degrade. The VCO noise performance will remain constant. At the recommended power level the PLL phase noise degradation from full power operation (8 dBm) is less than 2 dB. 30042827 FIGURE 10. Single-Ended LVPECL Operation, AC Coupling www.national.com 18 LMK01000 Family 30042830 FIGURE 13. Recommended OSCin Power for Operation with a Sine Wave Input 3.6 MORE THAN EIGHT OUTPUTS WITH AN LMK01000 FAMILY DEVICE The LMK01000 family device can be used in conjunction with a LMK02000, LMK03000, LMK04000, or even another LMK01000 device in order to produce more than 8 outputs. When doing this, attention needs to be given to how the frequencies are assigned for each output to eliminate synchronization issues. Refer to AN-1864 for more details. 3.7 GLOBAL DELAY THROUGH AN LMK01000 FAMILY DEVICE The delay from CLKin to CLKout is determinsic, but can vary based on the engaged delays and divides as discussed in Section 2.3.2 for the CLKoutX_MUX bit. In addition, there can be variations based on voltage, temperature, and frequency. AN-1864 discusses this global delay in more detail. 19 www.national.com LMK01000 Family Physical Dimensions inches (millimeters) unless otherwise noted Leadless Leadframe Package (Bottom View) 48 Pin LLP (SQA48A) Package Order Number Package Marking Packing LMK01000ISQX K01000 I 2500 Unit Tape and Reel 1000 Unit Tape and Reel LMK01000ISQ K01000 I LMK01000ISQE K01000 I 250 Unit Tape and Reel LMK01010ISQX K01010 I 2500 Unit Tape and Reel LMK01010ISQ K01010 I 1000 Unit Tape and Reel LMK01010ISQE K01010 I 250 Unit Tape and Reel LMK01020ISQX K01020 I 2500 Unit Tape and Reel LMK01020ISQ K01020 I 1000 Unit Tape and Reel LMK01020ISQE K01020 I 250 Unit Tape and Reel www.national.com 20 LMK01000 Family Notes 21 www.national.com LMK01000 Family 1.6 GHz High Performance Clock Buffer, Divider, and Distributor Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH(R) Tools www.national.com/webench Audio www.national.com/audio App Notes www.national.com/appnotes Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns Data Converters www.national.com/adc Samples www.national.com/samples Interface www.national.com/interface Eval Boards www.national.com/evalboards LVDS www.national.com/lvds Packaging www.national.com/packaging Power Management www.national.com/power Green Compliance www.national.com/quality/green Switching Regulators www.national.com/switchers Distributors www.national.com/contacts LDOs www.national.com/ldo Quality and Reliability www.national.com/quality LED Lighting www.national.com/led Feedback/Support www.national.com/feedback Voltage Reference www.national.com/vref Design Made Easy www.national.com/easy www.national.com/powerwise Solutions www.national.com/solutions Mil/Aero www.national.com/milaero PowerWise(R) Solutions Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors SolarMagicTM www.national.com/solarmagic Wireless (PLL/VCO) www.national.com/wireless www.national.com/training PowerWise(R) Design University THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION ("NATIONAL") PRODUCTS. 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