LMX1601

LMX1600/LMX1601/LMX1602 PLLatinum Low Cost Dual Frequency Synthesizer June 2005 LMX1600 2.0 GHz/500 MHz LMX1601 1.1 GHz/500 MHz LMX1602 1.1 GHz/1.1 GHz PLLatinum™ Low Cost Dual Frequency Synthesizer General Description The LMX1600/01/02 is part of a family of monolithic integrated dual frequency synthesizers designed to be used in a local oscillator subsystem for a radio transceiver. It is fabricated using National’s 0.5u ABiC V silicon BiCMOS process. The LMX1600/01/02 contains two dual modulus prescalers, four programmable counters, two phase detectors and two selectable gain charge pumps necessary to provide the control voltage for two external loop filters and VCO loops. Digital filtered lock detects for both PLLs are included. Data is transferred into the LMX1600/01/02 via a MICROWIRE™ serial interface (Data, Clock, LE). VCC supply voltage can range from 2.7V to 3.6V. The LMX1600/01/02 features very low current consumption typically 4.0 mA at 3V for LMX1601, 5.0 mA at 3V for LMX1600 or LMX1602. Powerdown for the PLL is hardware controlled. The LMX1600/01/02 is available in a 16 pin TSSOP surface mount plastic package. Features n VCC = 2.7V to 3.6V operation n Low current consumption: 4 mA @ 3V (typ) for LMX1601 5 mA @ 3V (typ) for LMX1600 or LMX1602 n PLL Powerdown mode: ICC = 1 µA typical n Digital Filtered Lock Detects n Dual modulus prescaler: — 2 GHz/500 MHz option: (Main) 32/33 (Aux) 8/9 — 1.1 GHz/500 MHz option: (Main) 16/17 (Aux) 8/9 — 1.1 GHz/1.1 GHz option: (Main) 16/17 (Aux) 16/17 Applications n Cordless / Cellular / PCS phones n Other digital mobile phones Functional Block Diagram 10012901 TRI-STATE ® is a registered trademark of National Semiconductor Corporation. MICROWIRE™ and PLLatinum™ are trademarks of National Semiconductor Corporation. © 2005 National Semiconductor Corporation DS100129 www.national.com LMX1600/LMX1601/LMX1602 Connection Diagrams 10012922 Order Number LMX1600SLB, LMX1601SLB, or LMX1602SLB NS Package Number SLB16A 10012902 Order Number LMX1600TM, LMX1601TM, or LMX1602TM NS Package Number MTC16 www.national.com 2 LMX1600/LMX1601/LMX1602 Pin Descriptions Pin No. for 16-pin CSP Package 16 Pin No. for 16-pin TSSOP Package 1 Pin Name I/O Description FoLD O Multiplexed output of the Main/Aux programmable or reference dividers and Main/Aux lock detect. CMOS output. (See Programming Description 2.5) PLL reference input which drives both the Main and Aux R counter inputs. Has about 1.2V input threshold and can be driven from an external CMOS or TTL logic gate. Typically connected to a TCXO output. Can be used with an external resonator (See Programming Description 2.5.4). Oscillator output. Used with an external resonator. Aux PLL ground. Aux prescaler input. Small signal input from the VCO. Aux PLL power supply voltage input. Must be equal to VCCMAIN. May range from 2.7V to 3.6V. Bypass capacitors should be placed as close as possible to this pin and be connected directly to the ground plane. Aux PLL Charge Pump output. Connected to a loop filter for driving the control input of an external VCO. Powers down the Aux PLL when LOW (N and R counters, prescaler, and tristates charge pump output). Bringing ENAUX HIGH powers up the Aux PLL. Powers down the Main PLL when LOW (N and R counters, prescaler, and tristates charge pump output). Bringing ENMAIN HIGH powers up the Main PLL. Main PLL Charge Pump output. Connected to a loop filter for driving the control input of an external VCO. Main PLL power supply voltage input. Must be equal to VCCAUX. May range from 2.7V to 3.6V. Bypass capacitors should be placed as close as possible to this pin and be connected directly to the ground plane. Main prescaler input. Small signal input from the VCO. Main PLL ground. Load enable high impedance CMOS input. Data stored in the shift registers is loaded into one of the 4 internal latches when LE goes HIGH (control bit dependent). High impedance CMOS input. Binary serial data input. Data entered MSB first. The last two bits are the control bits. High impedance CMOS Clock input. Data for the various counters is clocked in on the rising edge, into the 18-bit shift register. 1 2 OSCIN I 2 3 4 5 3 4 5 6 OSCOUT GND finAUX VCCAUX O — I — 6 7 7 8 CPoAUX ENAUX O I 8 9 ENMAIN I 9 10 10 11 CPoMAIN VCCMAIN O — 11 12 13 12 13 14 finMAIN GND LE I — I 14 15 15 16 Data Clock I I 3 www.national.com LMX1600/LMX1601/LMX1602 Absolute Maximum Ratings (Notes 2, 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Value Parameter Power Supply Voltage Voltage on any pin with GND=0V Storage Temperature Range Lead Temp. (solder 4 sec) ESD-Human Body Model (Note 2) Symbol VCCMAIN VCCAUX VI TS TL 2000 Min −0.3 −0.3 −0.3 −65 Typical Max 6.5 6.5 VCC + 0.3 +150 +260 Unit V V V ˚C ˚C eV Recommended Operating Conditions Value Parameter Power Supply Voltage Operating Temperature Symbol VCCMAIN VCCAUX TA Min 2.7 VCCMAIN −40 Typical Max 3.6 VCCMAIN +85 Unit V V ˚C Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Recommended Operating Conditions indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. Electrical Characteristics document specific minimum and/or maximum performance values at specified test conditions and are guaranteed. Typical values are for informational purposes only - based on design parameters or device characterization and are not guaranteed. Note 2: This device is a high performance RF integrated circuit and is ESD sensitive. Handling and assembly of this device should only be done on ESD-free workstations. Electrical Characteristics (VCCMAIN = VCCAUX = 3.0V; TA = 25˚C except as specified) Symbol GENERAL ICC Power Supply Current 2 GHz + 500 MHz 1.1 GHz + 500 MHz 1.1 GHz + 1.1 GHz 2 GHz Only 1.1 GHz Only 500 MHz Only ICC-PWDN fin Power Down Current fin Operating Frequency Crystal Mode (Note 3) Crystal Mode (Note 3) Crystal Mode (Note 3) Crystal Mode (Note 3) Crystal Mode (Note 3) Crystal Mode (Note 3) ENMAIN = LOW, ENAUX = LOW fin Main 2 GHz Option fin Main and Aux 1.1 GHz Option fin Aux 500 MHz Option OSCIN VOSC fφ Pfin ICPo-source ICPo-sink ICPo-source ICPo-sink ICPo-Tri VIH VIL www.national.com Parameter Conditions Min Typ 5.0 4.0 5.0 3.5 2.5 1.5 1 Max Units mA mA mA mA mA mA µA 200 100 40 1 1 0.5 10 −15 −1600 1600 −160 160 1 0.8VCC 2000 1100 500 40 20 VCC 0 MHz MHz MHz MHz MHz VPP MHz dBm µA µA µA µA nA V Oscillator Operating Frequency Oscillator Input Sensitivity Maximum Phase Detector Frequency Main and Aux RF Input Sensitivity Logic Mode (Note 3) Crystal Mode (Note 3) CHARGE PUMP RF Charge Pump Output Current (See VCPo = VCC/2, High Gain Mode Programming Description 2.4) VCPo = VCC/2, High Gain Mode VCPo = VCC/2, Low Gain Mode VCPo = VCC/2, Low Gain Mode Charge Pump TRI-STATE ® Current High-Level Input Voltage Low-Level Input Voltage 4 0.5 ≤ VCPo ≤ VCC−0.5 DIGITAL INTERFACE (DATA, CLK, LE, EN, FoLD) 0.2VCC V LMX1600/LMX1601/LMX1602 Electrical Characteristics Symbol IIH IIL IIH IIL IO Parameter High-Level Input Current Low-Level Input Current OSCIN Input Current OSCIN Input Current (Continued) (VCCMAIN = VCCAUX = 3.0V; TA = 25˚C except as specified) Conditions VIH = VCC = 3.6V, (Note 4) VIL = 0V; VCC = 3.6V, (Note 4) VIH = VCC = 3.6V VIL = 0V; VCC = 3.6V Logic Mode VCC = 3.6V (Note 3) VOUT = VCC/2 Crystal Mode VCC = 2.7V (Note 3) |300| −100 |200| Min −1.0 −1.0 Typ Max 1.0 1.0 100 Units µA µA µA µA µA OSCOUT Output Current Magnitude (sink/source) (Note 5) µA VOH VOL tCS tCH tCWH tCWL tES tEW RFφn High-Level Output Voltage Low-Level Output Voltage Data to Clock Set Up Time Data to Clock Hold Time Clock Pulse Width High Clock Pulse Width Low Clock to Load Enable Set Up Time Load Enable Pulse Width Main PLL Phase Noise Floor IOH = −500 µA IOL = 500 µA See Data Input Timing See Data Input Timing See Data Input Timing See Data Input Timing See Data Input Timing See Data Input Timing (Note 6) VCC−0.4 0.4 50 10 50 50 50 50 −160 V V ns ns ns ns ns ns dBc/Hz MICROWIRE TIMING CLOSED LOOP SYNTHESIZER PERFORMANCE (NSC evaluation board only) Note 3: Refer to Programming Description 2.5.3. Note 4: Except fin. Note 5: The OSCout Output Current Magnitude is lass than or equal to 200µA when the Logic Mode is selected. The OSCout Output Current Magnitude is greater than or equal to 300µA when the Crystal Mode is selected. Note 6: Offset frequency = 1 kHz, fin = 900 MHz, fφ = 25 kHz, N = 3600, fOSC = 10 MHz, VOSC > 1.2 VPP. Refer to the Application Note, AN-1052, for description of phase noise floor measurement. 5 www.national.com LMX1600/LMX1601/LMX1602 1.0 Functional Description The basic phase-lock-loop (PLL) configuration consists of a high-stability crystal reference oscillator, a frequency synthesizer such as the National Semiconductor LMX1600/01/02, a voltage controlled oscillator (VCO), and a passive loop filter. The frequency synthesizer includes a phase detector, current mode charge pump, as well as programmable reference [R], and feedback [N] frequency dividers. The VCO frequency is established by dividing the crystal reference signal down via the R counter to obtain the comparison frequency. This reference signal, fr, is then presented to the input of a phase/frequency detector and compared with another signal, fp, the feedback signal, which was obtained by dividing the VCO frequency down using the N counter. The phase/ frequency detector’s current source outputs pump charge into the loop filter, which then converts the charge into the VCO’s control voltage. The phase/frequency comparator’s function is to adjust the voltage presented to the VCO until the feedback signal’s frequency (and phase) match that of the reference signal. When this “phase-locked” condition exists, the VCO’s frequency will be N times that of the comparison frequency, where N is the divider ratio. 1.1 REFERENCE OSCILLATOR INPUTS The reference oscillator frequency for the Main and Aux PLL’s is provided by either an external reference through the OSCIN pin with the OSCOUT pin not connected or connected to a 30 pF capacitor to ground in Logic Mode, or an external crystal resonator across the OSCIN and OSCOUT pins in Crystal Mode (See Programming Description 2.5.3). The OSCIN input can operate to 40 MHz in Logic Mode or to 20 MHz in Crystal Mode with an input sensitivity of 0.5 VPP. The OSCIN pin drives the Main and Aux R counters. The inputs have a ∼ 1.2V input threshold and can be driven from an external CMOS or TTL logic gate. The OSCIN pin is typically connected to the output of a Temperature Compensated Crystal Oscillator (TCXO). 1.2 REFERENCE DIVIDERS (R COUNTERS) The Main and Aux R Counters are clocked through the oscillator block in common. The maximum frequency is 40 MHz in Logic Mode or 20 MHz in crystal Mode. Both R Counters are 12-bit CMOS counters with a divide range from 2 to 4,095. (See Programming Description 2.2) 1.3 FEEDBACK DIVIDERS (N COUNTERS) The Main and Aux N Counters are clocked by the small signal fin Main and fin Aux input pins respectively. These inputs should be AC coupled through external capacitors. The Main N counter has an 16-bit equivalent integer divisor configured as a 5-bit A Counter and an 11-bit B Counter offering a continuous divide range from 992 to 65,535 (2 GHz option) or a 4-bit A Counter and a 12-bit B Counter offering a continuous divide range from 240 to 65,535 (1.1 GHz option). The Main N divider incorporates a 32/33 dual modulus prescaler capable of operation from 200 MHz to 2.0 GHz or a 16/17 dual modulus prescaler capable of operation from 100 MHz to 1.1 GHz. The Aux N divider operates from 100 MHz to 1.1 GHz with a 16/17 prescaler or from 40 MHz to 500 MHz with a 8/9 prescaler. The Aux N counter is a 16-bit integer divider fully programmable from 240 to 65,535 over the frequency range of 100 MHz to 1.1 GHz or from 56 to 32,767 over the frequency range of 40 MHz to 550 MHz. The Aux N counter is configured as a 4-bit A Counter and a 12-bit B Counter. These inputs should be AC coupled through external capacitors. (See Programming Description 2.3) 1.3.1 Prescalers The RF input to the prescalers consists of the fin pins which are one of two complimentary inputs to a differential pair amplifier. The complimentary inputs are internally coupled to ground with a 10 pF capacitor and not brought out to a pin. The input buffer drives the A counter’s ECL D-type flip flops in a dual modulus configuration. A 32/33 for 2.0 GHz option, 16/17 for 1.1 GHz option, or 8/9 for 500 MHz option prescale ratio is provided for the LMX1600/01/02. The prescaler clocks the subsequent CMOS flip-flop chain comprising the fully programmable A and B counters. 1.4 PHASE/FREQUENCY DETECTOR The Main and Aux phase(/frequency) detectors are driven from their respective N and R counter outputs. The maximum frequency at the phase detector inputs is 10 MHz (unless limited by the minimum continuous divide ratio of the multi modulus prescalers). The phase detector outputs control the charge pumps. The polarity of the pump-up or pumpdown control is programmed using Main_PD_Pol or Aux_PD_Pol depending on whether Main or Aux VCO characteristics are positive or negative. (See Programming Description 2.4) The phase detector also receives a feedback signal from the charge pump in order to eliminate dead zone. 1.5 CHARGE PUMP The phase detector’s current source outputs pump charge into an external loop filter, which then converts the charge into the VCO’s control voltage. The charge pumps steer the charge pump output, CPo, to VCC (pump-up) or ground (pump-down). When locked, CPo is primarily in a TRISTATE mode with small corrections. The charge pump output current magnitude can be selected as 160 µA or 1600 µA using bits AUX_CP_GAIN and MAIN_CP_GAIN as shown in Programming Description 2.4. 1.6 MICROWIRE SERIAL INTERFACE The programmable functions are accessed through the MICROWIRE serial interface. The interface is made of 3 functions: clock, data, and latch enable (LE). Serial data for the various counters is clocked in from data on the rising edge of clock, into the 18-bit shift register. Data is entered MSB first. The last two bits decode the internal register address. On the rising edge of LE, data stored in the shift register is loaded into one of the 4 appropriate latches (selected by address bits). Data is loaded from the latch to the counter when counter reaches to zero. A complete programming description is included in the following sections. 1.7 FoLD MULTIFUNCTION OUTPUT The LMX1600/01/02 programmable output pin (FoLD) can deliver the internal counter outputs, digital lock detects, or CMOS high/low levels. 1.7.1 Lock Detect A digital filtered lock detect function is included with each phase detector through an internal digital filter to produce a logic level output available on the Fo/LD output pin, if selected. The lock detect output is high when the error between the phase detector inputs is less than 15 ns for 4 consecutive 6 www.national.com LMX1600/LMX1601/LMX1602 1.0 Functional Description (Continued) comparison cycles. The lock detect output is low when the error between the phase detector outputs is more than 30 ns for one comparison cycle. The lock detect output is always low when the PLL is in power down mode. For further description see Programming Description 2.5. 1.8 POWER CONTROL Each PLL is individually power controlled by the device EN pin. The ENMAIN controls the Main PLL, and the ENAUX controls the Aux PLL. Activation of EN = LOW (power down) condition results in the disabling of the respective N and R counters and de-biasing of their respective fin inputs (to a high impedance state). The reference oscillator input block powers down and the OSCIN pin reverts to a high impedance state only when both EN pins are LOW. Power down forces the respective charge pump and phase comparator logic to a TRI-STATE condition as well as disabling the bandgap reference block. Power up occurs immediately when the EN pin is brought high. Power up sequence: Bandgap and Oscillator blocks come up first, with the remaining PLL functions becoming active approx. 1 µs later. All programming information is retained internally in the chip when in power down mode. The MICROWIRE control register remains active and capable of loading and latching in data during power down mode. 2.0 Programming Description 2.1 MICROWIRE INTERFACE The descriptions below detail the 18-bit data register loaded through the MICROWIRE Interface. The 18-bit shift register is used to program the 12-bit Main and Aux R counter registers and the 16-bit Main and Aux N counter registers. The shift register consists of a 16-bit DATA field and a 2-bit control (CTL [1:0]) field as shown below. The control bits decode the internal register address. On the rising edge of LE, data stored in the shift register is loaded into one of the 4 appropriate latches (selected by address bits). Data is shifted in MSB first. MSB DATA [15:0] 18 21 LSB CTL [1:0] 0 2.1.1 Register Location Truth Table When LE transitions high, data is transferred from the 18-bit shift register into one of the 4 appropriate internal latches depending upon the state of the control (CTL) bits. The control bits decode the internal register address CTL [1:0] 0 0 1 1 2.1.2 Register Content Truth Table First Bit 17 AUX_R AUX_N MAIN_R MAIN_N 2.2 CP_WORD 16 15 14 13 12 FoLD AUX_B_CNTR MAIN_R_CNTR MAIN_B_CNTR and MAIN_A_CNTR SHIFT REGISTER BIT LOCATION 11 10 9 8 7 6 5 4 3 2 AUX_R_CNTR AUX_A_CNTR Last Bit 1 0 0 1 1 0 0 1 0 1 0 1 0 1 DATA Location AUX_R Register AUX_N Register MAIN_R Register MAIN_N Register PROGRAMMABLE REFERENCE DIVIDERS 2.2.1 AUX_R Register If the Control Bits (CTL [1:0]) are 0 0 when LE transitions high, data is transferred from the 18-bit shift register into a latch which sets the Aux PLL 12-bit R counter divide ratio. The divide ratio is programmed using the bits AUX_R_CNTR as shown in table 2.2.3. The divider ratio must be ≥ 2. The FoLD word bits controls the multifunction FoLD output as described in section in 2.5. First Bit 17 AUX_R 16 15 14 13 12 FoLD[3:0] SHIFT REGISTER BIT LOCATION 11 10 9 8 7 6 5 4 3 2 AUX_R_CNTR[11:0] Last Bit 1 0 0 0 7 www.national.com LMX1600/LMX1601/LMX1602 2.0 Programming Description 2.2.2 MAIN_R REGISTER (Continued) If the Control Bits (CTL [1:0]) are 1 0 when LE transitions high, data is transferred from the 18-bit shift register into a latch which sets the Main PLL 12-bit R counter divide ratio and various control functions. The divide ratio is programmed using the bits MAIN_R_CNTR as shown in table 2.2.3. The divider ratio must be ≥ 2. The charge pump control word (CP_WORD[3:0] ) sets the charge pump gain and the phase detector polarity as detailed in 2.4. First Bit 17 MAIN_R 16 15 14 13 12 CP_WORD[3:0] SHIFT REGISTER BIT LOCATION 11 10 9 8 7 6 5 4 3 2 MAIN_R_CNTR[11:0] Last Bit 1 1 0 0 2.2.3 12-Bit Programmable Main and Auxiliary Reference Divider Ratio (MAIN/AUX R Counter) MAIN_R_CNTR/AUX_R_CNTR Divide Ratio 2 3 11 0 0 10 0 0 9 0 0 8 0 0 7 0 0 6 0 0 5 0 0 4 0 0 3 0 0 2 0 0 1 1 1 0 0 1 • 4,095 Note 7: Legal divide ratio: 2 to 4,095. • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 2.3 PROGRAMMABLE FEEDBACK (N) DIVIDERS 2.3.1 AUX_N Register If the Control Bits ( CTL[1:0]) are 0 1 when LE transitions high, data is transferred from the 18-bit shift register into the AUX_N register latch which sets the Aux PLL 16-bit programmable N counter value. The AUX_N counter is a 16-bit counter which is fully programmable from 240 to 65,535 for 1.1 GHz option or from 56 to 32,767 for 500 MHz option. The AUX_N register consists of the 4-bit swallow counter (AUX_A_CNTR), the 12-bit programmable counter (AUX_B_CNTR). Serial data format is shown below. The divide ratio (AUX_N_CNTR [13:0]) must be ≥ 240 (1.1 GHz option) or ≥ 56 (500 MHz option) for a continuous divide range. The Aux PLL N divide ratio is programmed using the bits AUX_A_CNTR, AUX_B_CNTR as shown in tables 2.3.2. First Bit 17 AUX_N 2.3.2 16 15 14 13 12 SHIFT REGISTER BIT LOCATION 11 10 9 8 7 6 5 4 3 2 AUX_B_CNTR[11:0] AUX_A_CNTR[3:0] Last Bit 1 0 0 1 4-BIT Swallow Counter Divide Ratio (Aux A COUNTER) 1.1 GHz option Swallow Count (A) 0 1 3 0 0 AUX_A_CNTR 2 0 0 1 0 0 0 0 1 Swallow Count (A) 1 3 X AUX_A_CNTR 2 0 1 0 0 1 • 7 X = Don’t Care condition • X • 1 • 1 • 1 • 15 • 1 • 1 • 1 • 1 Note 9: Swallow Counter Value: 0 to 7 Note 8: Swallow Counter Value: 0 to 15 500 MHz option Swallow Count (A) 0 3 X AUX_A_CNTR 2 0 1 0 0 0 www.national.com 8 LMX1600/LMX1601/LMX1602 2.0 Programming Description 2.3.3 (Continued) 12-BIT Programmable Counter Divide Ratio (Aux B COUNTER) AUX_B_CNTR Divide Ratio 3 4 11 0 0 10 0 0 9 0 0 8 0 0 7 0 0 6 0 0 5 0 0 4 0 0 3 0 0 2 0 1 1 1 0 0 1 0 • 4,095 AUX_B_CNTR ≥ AUX_A_CNTR. • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 Note 10: Divide ratio: 3 to 4,095 (Divide ratios less than 3 are prohibited) See section 2.3.7 for calculation of VCO output frequency. 2.3.4 MAIN_N Register If the Control Bits (CTL[1:0]) are 1 1 when LE transitions high, data is transferred from the 18-bit shift register into the MAIN_N register latch which sets 16-bit programmable N divider value. The Main N divider is a 16-bit counter which is fully programmable from 992 to 65,535 for 2 GHz option and from 240 to 65,535 for 1.1 GHz option. The MAIN_N register consists of the 5-bit (2 GHz option) or 4-bit (1.1 GHz option) swallow counter (MAIN_A_CNTR) and the 11-bit (2 GHz option) or 12-bit (1.1 GHz option) programmable counter (MAIN_B_CNTR). Serial data format for the MAIN_N register latch shown below. The divide ratio must be ≥ 992 (2 GHz option) or > 240 (1.1 GHz option) for a continuous divide range. The divide ratio is programmed using the bits MAIN _A_CNTR and MAIN_B_CNTR as shown in tables 2.3.5 and 2.3.6 The pulse swallow function which determines the divide ratio is described in Section 2.3.7. 2 GHz option First Bit 17 MAIN_N 16 15 14 13 12 SHIFT REGISTER BIT LOCATION 11 10 9 8 7 6 5 4 3 2 AUX_B_CNTR[10:0] 1.1 GHz option First Bit 17 MAIN_N 2.3.5 16 15 14 13 12 SHIFT REGISTER BIT LOCATION 11 10 9 8 7 6 5 4 3 2 AUX_B_CNTR[11:0] AUX_A_CNTR[3:0] Last Bit 1 1 0 1 AUX_A_CNTR[4:0] Last Bit 1 1 0 1 Swallow Counter Divide Ratio (Main A COUNTER) 2 GHz option (5 bit) Swallow Count (A) 0 1 4 0 0 MAIN_A_CNTR 3 0 0 2 0 0 1 0 0 0 0 1 1.1 GHz option (4 bit) Swallow Count (A) 0 1 MAIN_A_CNTR 3 0 0 2 0 0 1 0 0 0 0 1 • 31 • 1 • 1 • 1 • 1 • 1 • 15 • 1 • 1 • 1 • 1 Note 11: Swallow Counter Value: 0 to 31 Note 12: Swallow Counter Value: 0 to 15 9 www.national.com LMX1600/LMX1601/LMX1602 2.0 Programming Description 2.3.6 (Continued) Programmable Counter Divide Ratio (Main B COUNTER) 2 GHz option (11 bit) MAIN_B_CNTR Divide Ratio 3 4 10 0 0 9 0 0 8 0 0 7 0 0 6 0 0 5 0 0 4 0 0 3 0 0 2 0 1 1 1 0 0 1 0 • 2,047 MAIN_B_CNTR ≥ MAIN_A_CNTR. • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 Note 13: Divide ratio: 3 to 2,047 (Divide ratios less than 3 are prohibited) See section 2.3.7 for calculation of VCO output frequency. 1.1 GHz option (12 bit) MAIN_B_CNTR Divide Ratio 3 4 11 0 0 10 0 0 9 0 0 8 0 0 7 0 0 6 0 0 5 0 0 4 0 0 3 0 0 2 0 1 1 1 0 0 1 0 • 4,095 MAIN_B_CNTR ≥ MAIN_A_CNTR. • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 Note 14: Divide ratio: 3 to 4,095 (Divide ratios less than 3 are prohibited) See section 2.3.7 for calculation of VCO output frequency. 2.3.7 Pulse Swallow Function The N divider counts such that it divides the VCO RF frequency by (P+1) for A times, and then divides by P for (B – A ) times. The B value (B_CNTR) must be ≥ 3. The continuous divider range for the Main PLL N divider is from 992 to 65,535 for 2 GHz option, from 240 to 65,535 for 1.1 GHz option, and from 56 to 32,767 for 500 MHz option. Divider ratios less than the minimum value are achievable as long as the binary counter value is greater than or equal to the swallow counter value (B_CNTR ≥ A_CNTR). fVCO = N x ( fOSC / R ) N = (P x B) + A fVCO: Output frequency of external voltage controlled oscillator (VCO) fOSC: Output frequency of the external reference frequency oscillator (input to OSCIN). R: N: B: A: P: Preset divide ratio of binary programmable reference counter (R_CNTR) Preset divide ratio of main programmable integer N counter (N_CNTR) Preset divide ratio of binary programmable B counter (B_CNTR) Preset value of binary 4-bit swallow A counter (A _CNTR) Preset modulus of dual modulus prescaler (P = 32 for 2 GHz option, P=16 for 1.1 GHz option, and P=8 for 500 MHz option) www.national.com 10 LMX1600/LMX1601/LMX1602 2.0 Programming Description 2.4 MSB AUX_CP_GAIN (Continued) CHARGE PUMP CONTROL WORD (CP_WORD) LSB MAIN_CP_GAIN AUX_PD_POL MAIN_PD_POL BIT AUX_CP_GAIN MAIN_CP_GAIN AUX_PD_POL MAIN_PD_POL LOCATION MAIN_R[17] MAIN_R[16] MAIN_R[15] MAIN_R[14] FUNCTION Aux Charge Pump Current Gain Main Charge Pump Current Gain Aux Phase Detector Polarity Main Phase Detector Polarity 0 LOW LOW Negative Negative 1 HIGH HIGH Positive Positive AUX_CP_GAIN (MAIN_R[17]) and MAIN_CP_GAIN (MAIN_R[16]) are used to select charge pump current magnitude either low gain mode (160 µA typ) or high gain mode (1600 µA typ) AUX_ PD_POL (MAIN_R[15]) and MAIN_ PD_POL (MAIN_R[14]) are respectively set to one when Aux or Main VCO characteristics are positive as in (1) below. When VCO frequency decreases with increasing control voltage (2) PD_POL should set to zero. 2.4.1 VCO Characteristics 10012914 2.4.2 Phase Comparator and Internal Charge Pump Characteristics (AUX_PD_POL/MAIN_PD_POL = 1) 10012915 Note 15: fr is phase detector input from reference counter. fp is phase detector input from programmable N counter. Phase difference detection range: - 2π to + 2pπ. The minimum width pump up and pump down current pulses occur at the CPo pin when the loop is locked. 2.5 FOUT/LOCK DETECT PROGRAMMING TRUTH TABLE (FoLD) FoLD 3 AUX_R[17] 0 0 0 2 AUX_R[16] 0 0 0 1 AUX_R[15] 0 0 1 0 AUX_R[14] 0 1 X “0” “1” Main Lock Detect Fo/LD OUTPUT STATE 11 www.national.com LMX1600/LMX1601/LMX1602 2.0 Programming Description FoLD 0 0 1 1 1 1 1 1 0 0 1 1 0 1 0 1 0 1 (Continued) Fo/LD OUTPUT STATE x X X X X X Aux Lock Detect Main “and” Aux Lock Detect Main Reference Counter Output Aux Reference Counter Output Main Programmable Counter Output Aux Programmable Counter Output Note 16: See section 2.5.3 for AUX_R[14] description. 2.5.1 Lock Detect Digital Filter The Lock Detect Digital Filter compares the difference between the phase of the inputs of the phase detector to a RC generated delay of approximately 15 ns. To enter the locked state (Lock = HIGH) the phase error must be less than the 15 ns RC delay for 4 consecutive reference cycles. Once in lock (Lock = HIGH), the RC delay is changed to approximately 30 ns. To exit the locked state (Lock = LOW), the phase error must become greater than the 30 ns RC delay. When the PLL is in the powerdown mode, Lock is forced LOW. A flow chart of the digital filter is shown below. 10012916 www.national.com 12 LMX1600/LMX1601/LMX1602 2.0 Programming Description 2.5.2 (Continued) Typical Lock Detect Timing (AUX_PD_POL/MAIN_PD_POL = 1) 10012917 2.5.3 OSC Mode Programming The OSCout pin can be optimized for operating with an external crystal resonator or an external reference frequency source (i.e. TCXO). If the application uses an external reference frequency source, the current dissipation of the LMX1600/01/02 can be reduced with the Logic Mode (0.5 mA typ.). Crystal Mode should be used when an external crystal resonator is used. Logic Mode is used when an external reference frequency source is used. In Logic Mode, OSCOUT should be connected to a 30 pF capacitor to ground for optimum performance. When the FoLD output state is selected to CMOS high/low levels, the OSC Mode is forced to Crystal Mode. FoLD 3 AUX_R[17] 0 0 2 AUX_R[16] 0 0 All Other States 1 AUX_R[15] 0 0 0 AUX_R[14] 0 1 0 1 Crystal Mode Crystal Mode Logic Mode Crystal Mode OSCOUT 2.5.4 Typical Crystal Oscillator Circuit A typical implementation of a 10 MHz crystal oscillator with the OSCOUT pin in Crystal Mode is shown below. 10012918 13 www.national.com LMX1600/LMX1601/LMX1602 2.0 Programming Description 2.6 SERIAL DATA INPUT TIMING (Continued) 10012919 Note 17: Data shifted into register on clock rising edge. Data is shifted in MSB first. TEST CONDITIONS: The Serial Data Input Timing is tested using a symmetrical waveform around VCC/2. The test waveform has an edge rate of 0.6 V/ns with amplitudes of 2.2V @ VCC = 2.7V. www.national.com 14 LMX1600/LMX1601/LMX1602 2.0 Programming Description 2.7 TYPICAL APPLICATION EXAMPLE (Continued) 10012920 OPERATIONAL NOTES: * VCO is assumed AC coupled. ** RIN increases impedance so that VCO output power is provided to the load rather than the PLL. Typical values are 10Ω to 200Ω depending on the VCO power level. The fin RF impedance ranges from 40Ω to 100Ω. The fin IF impedances are higher. *** 50Ω termination is often used on test boards to allow use of external reference oscillator. For most typical products, a CMOS clock is used and no terminating resistor is required. OSCIN may be AC or DC coupled. AC coupling is recommended because the input circuit provides its own bias. (See Figure below) 10012921 **** Adding RC filter to the VCC line is recommended to reduce loop-to-loop noise coupling. — Proper use of grounds and bypass capacitors is essential to achieve a high level of performance. Crosstalk between pins can be reduced by careful board layout. — This is a static sensitive device. It should be handled only at static free work stations. 15 www.national.com LMX1600/LMX1601/LMX1602 Physical Dimensions inches (millimeters) unless otherwise noted Dimensions are in millimeters. 16-Pin TSSOP Package (MTC16) Order Number LMX1600TM, LMX1601TM, or LMX1602TM NS Package Number MTC16 www.national.com 16 LMX1600/LMX1601/LMX1602 PLLatinum Low Cost Dual Frequency Synthesizer Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 16-Pin CSP Package (SLB16A) Order Number LMX1600SLB, LMX1601SLB, or LMX1602SLB NS package SLB16A National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. For the most current product information visit us at www.national.com. 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