Integrated Synthesizer and VCO ADF4360-8 FEATURES GENERAL DESCRIPTION Output frequency range: 65 MHz to 400 MHz 3.0 V to 3.6 V power supply 1.8 V logic compatibility Integer-N synthesizer Programmable output power level 3-wire serial interface Digital lock detect Hardware and software power-down mode The ADF4360-8 is an integrated integer-N synthesizer and voltage-controlled oscillator (VCO). The ADF4360-8 center frequency is set by external inductors. This allows a frequency range of between 65 MHz to 400 MHz. Control of all the on-chip registers is through a simple 3-wire interface. The device operates with a power supply ranging from 3.0 V to 3.6 V and can be powered down when not in use. APPLICATIONS System clock generation Test equipment Wireless LANs CATV equipment FUNCTIONAL BLOCK DIAGRAM AVDD DVDD RSET CE ADF4360-8 MUXOUT MULTIPLEXER REFIN 14-BIT R COUNTER LOCK DETECT CLK DATA 24-BIT DATA REGISTER LE MUTE 24-BIT FUNCTION LATCH CHARGE PUMP CP PHASE COMPARATOR VVCO VTUNE L1 L2 CC CN RFOUTA VCO CORE 13-BIT B COUNTER OUTPUT STAGE RFOUTB 04763-001 N=B AGND DGND CPGND Figure 1. Rev. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. 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ADF4360-8 TABLE OF CONTENTS Specifications..................................................................................... 3 Output Stage................................................................................ 12 Timing Characteristics ................................................................ 5 Latch Structure ........................................................................... 13 Absolute Maximum Ratings............................................................ 6 Power-Up..................................................................................... 17 Transistor Count........................................................................... 6 Control Latch .............................................................................. 19 ESD Caution.................................................................................. 6 N Counter Latch......................................................................... 20 Pin Configuration and Function Descriptions............................. 7 R Counter Latch ......................................................................... 20 Typical Performance Characteristics ............................................. 8 Applications..................................................................................... 21 Circuit Description......................................................................... 10 Choosing the Correct Inductance Value ................................. 21 Reference Input Section............................................................. 10 Fixed Frequency LO................................................................... 21 N Counter.................................................................................... 10 Interfacing ................................................................................... 22 R Counter .................................................................................... 10 PCB Design Guidelines for Chip Scale Package........................... 22 PFD and Charge Pump.............................................................. 10 Output Matching ........................................................................ 23 MUXOUT and Lock Detect...................................................... 10 Outline Dimensions ....................................................................... 24 Input Shift Register..................................................................... 11 Ordering Guide .......................................................................... 24 VCO.............................................................................................. 11 REVISION HISTORY 01/05 — Rev. 0 to Rev. A Changes to Table 1............................................................................ 3 Changes to Table 2............................................................................ 5 Changes to Figure 20...................................................................... 12 Added Power-Up Section .............................................................. 17 Deleted Power-Up Section ............................................................ 22 Updated Outline Dimensions ....................................................... 24 Changes to Ordering Guide .......................................................... 24 10/04—Revision 0: Initial Version Rev. A | Page 2 of 24 ADF4360-8 SPECIFICATIONS1 AVDD = DVDD = VVCO = 3.3 V ± 10%; AGND = DGND = 0 V; TA = TMIN to TMAX, unless otherwise noted. Table 1. Parameter REFIN CHARACTERISTICS REFIN Input Frequency B Version Unit Conditions/Comments 10/250 MHz min/max 0.7/AVDD 0 to AVDD 5.0 ±60 V p-p min/max V max pF max µA max For f < 10 MHz, use a dc-coupled CMOS-compatible square wave, slew rate > 21 V/µs. AC-coupled CMOS-compatible 8 MHz max 2.5 0.312 2.7/10 0.2 2 1.5 2 mA typ mA typ kΩ nA typ % typ % typ % typ 1.5 0.6 ±1 3.0 V min V max µA max pF max DVDD – 0.4 500 0.4 V min µA max V max 3.0/3.6 AVDD AVDD 5 2.5 12.0 3.5 to 11.0 7 V min/V max 400 MHz Minimum VCO Output Frequency VCO Output Frequency 65 88/108 MHz MHz min/max VCO Frequency Range VCO Sensitivity 1.2 2 Ratio MHz/V typ Lock Time6 Frequency Pushing (Open Loop) Frequency Pulling (Open Loop) Harmonic Content (Second) 400 0.24 10 −16 µs typ MHz/V typ Hz typ dBc typ REFIN Input Sensitivity REFIN Input Capacitance REFIN Input Current PHASE DETECTOR Phase Detector Frequency2 CHARGE PUMP ICP Sink/Source3 High Value Low Value RSET Range ICP Three-State Leakage Current Sink and Source Current Matching ICP vs. VCP ICP vs. Temperature LOGIC INPUTS VINH, Input High Voltage VINL, Input Low Voltage IINH/IINL, Input Current CIN, Input Capacitance LOGIC OUTPUTS VOH, Output High Voltage IOH, Output High Current VOL, Output Low Voltage POWER SUPPLIES AVDD DVDD VVCO AIDD4 DIDD4 IVCO4, 5 IRFOUT4 Low Power Sleep Mode4 RF OUTPUT CHARACTERISTICS5 Maximum VCO Output Frequency With RSET = 4.7 kΩ 1.25 V ≤ VCP ≤ 2.5 V 1.25 V ≤ VCP ≤ 2.5 V VCP = 2.0 V CMOS output chosen IOL = 500 µA mA typ mA typ mA typ mA typ µA typ ICORE = 5 mA RF output stage is programmable ICORE = 5 mA. Depending on L. See the Choosing the Correct Inductance Value section. L1, L2 = 270 nH. See the Choosing the Correct Inductance Value section for other frequency values. FMAX / FMIN L1, L2 = 270 nH. See the Choosing the Correct Inductance Value section for other sensitivity values. To within 10 Hz of final frequency Into 2.00 VSWR load Rev. A | Page 3 of 24 ADF4360-8 Parameter Harmonic Content (Third) Output Power5, 7 Output Power5, 8 Output Power Variation VCO Tuning Range NOISE CHARACTERISTICS5 VCO Phase Noise Performance9 Synthesizer Phase Noise Floor10 Phase Noise Figure of Merit10 In-Band Phase Noise11, 12 RMS Integrated Phase Error13 Spurious Signals due to PFD Frequency12, 14 Level of Unlocked Signal with MTLD Enabled B Version −21 −9/0 −14/−9 ±3 1.25/2.5 Unit dBc typ dBm typ dBm typ dB typ V min/max −120 −139 −140 −142 −160 −150 −142 −215 −102 0.09 −75 dBc/Hz typ dBc/Hz typ dBc/Hz typ dBc/Hz typ dBc/Hz typ dBc/Hz typ dBc/Hz typ dBc/Hz typ dBc/Hz typ Degrees typ dBc typ −70 dBm typ Conditions/Comments Using tuned load, programmable in 3 dB steps; see Table 7 Using 50 Ω resistors to VVCO, programmable in 3 dB steps; see Table 7 @ 100 kHz offset from carrier @ 800 kHz offset from carrier @ 3 MHz offset from carrier @ 10 MHz offset from carrier @ 200 kHz PFD frequency @ 1 MHz PFD frequency @ 8 MHz PFD frequency @ 1 kHz offset from carrier 100 Hz to 100 kHz 1 Operating temperature range is –40°C to +85°C. Guaranteed by design. Sample tested to ensure compliance. 3 ICP is internally modified to maintain constant loop gain over the frequency range. 4 TA = 25°C; AVDD = DVDD = VVCO = 3.3 V. 5 Unless otherwise stated, these characteristics are guaranteed for VCO core power = 5 mA. L1, L2 = 270 nH, 470 Ω resistors to GND in parallel with L1, L2. 6 Jumping from 88 MHz to 108 MHz. PFD frequency = 200 kHz; loop bandwidth = 10 kHz. 7 For more detail on using tuned loads, see the Output Matching section. 8 Using 50 Ω resistors to VVCO, into a 50 Ω load. 9 The noise of the VCO is measured in open-loop conditions. 10 The synthesizer phase noise floor is estimated by measuring the in-band phase noise at the output of the VCO and subtracting 20 log N (where N is the N divider value). The phase noise figure of merit subtracts 10 log (PFD frequency). 11 The phase noise is measured with the EVAL-ADF4360-xEB1 Evaluation Board and the HP 8562E Spectrum Analyzer. The Spectrum Analyzer provides the REFIN for the synthesizer; offset frequency = 1 kHz. 12 fREFIN = 10 MHz; fPFD = 200 kHz; N = 1000; loop B/W = 10 kHz. 13 fREFIN = 10 MHz; fPFD = 1 MHz; N = 120; loop B/W = 100 kHz. 14 The spurious signals are measured with the EVAL-ADF4360-xEB1 Evaluation Board and the HP 8562E Spectrum Analyzer. The Spectrum Analyzer provides the REFIN for the synthesizer; fREFOUT = 10 MHz @ 0 dBm. 2 Rev. A | Page 4 of 24 ADF4360-8 TIMING CHARACTERISTICS1 AVDD = DVDD = VVCO = 3.3 V ± 10%; AGND = DGND = 0 V; 1.8 V and 3 V logic levels used; TA = TMIN to TMAX, unless otherwise noted. Table 2. Parameter t1 t2 t3 t4 t5 t6 t7 Unit ns min ns min ns min ns min ns min ns min ns min Test Conditions/Comments LE setup time DATA to CLOCK setup time DATA to CLOCK hold time CLOCK high duration CLOCK low duration CLOCK to LE setup time LE pulse width Refer to the Power-Up section for the recommended power-up procedure for this device. t4 t5 CLOCK t2 DATA DB23 (MSB) t3 DB22 DB2 DB1 (CONTROL BIT C2) DB0 (LSB) (CONTROL BIT C1) t7 LE t1 t6 04763-002 1 Limit at TMIN to TMAX (B Version) 20 10 10 25 25 10 20 LE Figure 2. Timing Diagram Rev. A | Page 5 of 24 ADF4360-8 ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. Table 3. Parameter AVDD to GND1 AVDD to DVDD VVCO to GND VVCO to AVDD Digital I/O Voltage to GND Analog I/O Voltage to GND REFIN to GND Operating Temperature Range Storage Temperature Range Maximum Junction Temperature CSP θJA Thermal Impedance Paddle Soldered Paddle Not Soldered Lead Temperature, Soldering Vapor Phase (60 sec) Infrared (15 sec) 1 Rating −0.3 V to +3.9 V −0.3 V to +0.3 V −0.3 V to +3.9 V −0.3 V to +0.3 V −0.3 V to VDD + 0.3 V −0.3 V to VDD + 0.3 V −0.3 V to VDD + 0.3 V −40°C to + 85°C −65°C to +150°C 150°C 50°C/W 88°C/W Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. This device is a high performance RF integrated circuit with an ESD rating of <1 kV, and it is ESD sensitive. Proper precautions should be taken for handling and assembly. TRANSISTOR COUNT 12543 (CMOS) and 700 (Bipolar) 215°C 220°C GND = AGND = DGND = 0 V. ESD CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. Rev. A | Page 6 of 24 ADF4360-8 19 LE 20 MUXOUT 22 AGND 21 DVDD 23 CE 24 CP PIN CONFIGURATION AND FUNCTION DESCRIPTIONS PIN 1 IDENTIFIER CPGND 1 AVDD 2 18 DATA 17 CLK CN VVCO 6 13 RSET 04763-003 14 CC 12 DGND RFOUTB 5 AGND 11 15 L2 10 TOP VIEW (Not to Scale) REFIN RFOUTA 4 L1 9 16 VTUNE 7 ADF4360-8 AGND 8 AGND 3 Figure 3. Pin Configuration Table 4. Pin Function Descriptions Pin No. 1 2 Mnemonic CPGND AVDD 3, 8, 11, 22 4 AGND RFOUTA 5 RFOUTB 6 VVCO 7 VTUNE 9 L1 10 L2 12 13 CC RSET Description Charge Pump Ground. This is the ground return path for the charge pump. Analog Power Supply. This ranges from 3.0 V to 3.6 V. Decoupling capacitors to the analog ground plane should be placed as close as possible to this pin. AVDD must have the same value as DVDD. Analog Ground. This is the ground return path of the prescaler and VCO. VCO Output. The output level is programmable from 0 dBm to −9 dBm. See the Output Matching section for a description of the various output stages. VCO Complementary Output. The output level is programmable from 0 dBm to −9 dBm. See the Output Matching section for a description of the various output stages. Power Supply for the VCO. This ranges from 3.0 V to 3.6 V. Decoupling capacitors to the analog ground plane should be placed as close as possible to this pin. VVCO must have the same value as AVDD. Control Input to the VCO. This voltage determines the output frequency and is derived from filtering the CP output voltage. An external inductor to AGND should be connected to this pin to set the ADF4360-8 output frequency. L1 and L2 need to be the same value. A 470 Ω resistor should be added in parallel to AGND. An external inductor to AGND should be connected to this pin to set the ADF4360-8 output frequency. L1 and L2 need to be the same value. A 470 Ω resistor should be added in parallel to AGND. Internal Compensation Node. This pin must be decoupled to ground with a 10 nF capacitor. Connecting a resistor between this pin and CPGND sets the maximum charge pump output current for the synthesizer. The nominal voltage potential at the RSET pin is 0.6 V. The relationship between ICP and RSET is I CPmax = 14 15 16 CN DGND REFIN 17 CLK 18 DATA 19 LE 20 MUXOUT 21 DVDD 23 CE 24 CP 11.75 RSET where RSET = 4.7 kΩ, ICPmax = 2.5 mA. Internal Compensation Node. This pin must be decoupled to VVCO with a 10 µF capacitor. Digital Ground. Reference Input. This is a CMOS input with a nominal threshold of VDD/2 and a dc equivalent input resistance of 100 kΩ (see Figure 16). This input can be driven from a TTL or CMOS crystal oscillator, or it can be ac-coupled. Serial Clock Input. This serial clock is used to clock in the serial data to the registers. The data is latched into the 24-bit shift register on the CLK rising edge. This input is a high impedance CMOS input. Serial Data Input. The serial data is loaded MSB first with the two LSBs being the control bits. This input is a high impedance CMOS input. Load Enable, CMOS Input. When LE goes high, the data stored in the shift registers is loaded into one of the four latches, and the relevant latch is selected using the control bits. This multiplexer output allows either the lock detect, the scaled RF, or the scaled reference frequency to be accessed externally. Digital Power Supply. This ranges from 3.0 V to 3.6 V. Decoupling capacitors to the digital ground plane should be placed as close as possible to this pin. DVDD must have the same value as AVDD. Chip Enable. A logic low on this pin powers down the device and puts the charge pump into three-state mode. Taking the pin high powers up the device depending on the status of the power-down bits. Charge Pump Output. When enabled, this provides ±ICP to the external loop filter, which in turn drives the internal VCO. Rev. A | Page 7 of 24 ADF4360-8 –40 0 –50 –10 –60 –20 –70 OUTPUT POWER (dB) –80 –90 –100 –110 –120 –30 –40 –50 –60 –70 –84dBc –150 100 1k 10k 100k FREQUENCY OFFSET (Hz) 1M 04763-007 04763-004 –140 –90 –1.1MHz 10M –0.55MHz 65MHz 0.55MHz 1.1MHz Figure 7. Reference Spurs at 65 MHz (1 MHz Channel Spacing, 100 kHz Loop Bandwidth) Figure 4. Open-Loop VCO Phase Noise, L1, L2 = 560 nH –40 –70 –75 –50 –80 –85 –90 –95 –100 –60 OUTPUT POWER (dB) –105 –110 –115 –120 –125 –130 –135 –70 –80 –90 –100 –110 –120 –130 04763-005 –140 –145 –150 100 1k 10k 100k FREQUENCY OFFSET (Hz) 1M 04763-008 OUTPUT POWER (dB) VDD = 3.3V, V VCO = 3.3V ICP = 2.5mA PFD FREQUENCY = 1MHz LOOP BANDWIDTH = 100kHz RES. BANDWIDTH = 1kHz VIDEO BANDWIDTH = 1kHz SWEEP = 4.2SECONDS AVERAGES = 20 –80 –130 –140 –150 100 10M Figure 5. VCO Phase Noise, 65 MHz, 1 MHz PFD, 100 kHz Loop Bandwidth 1k 10k 100k FREQUENCY OFFSET (Hz) 1M 10M Figure 8. Open-Loop VCO Phase Noise, L1, L2 = 110 nH 0 –70 –20 –30 –40 VDD = 3.3V, VVCO = 3.3V ICP = 2.5mA PFD FREQUENCY = 1MHz LOOP BANDWIDTH = 100kHz RES. BANDWIDTH = 30Hz VIDEO BANDWIDTH = 30Hz SWEEP = 1.9SECONDS AVERAGES = 20 –75 OUTPUT POWER (dB) REFERENCE LEVEL = –2.5dBm –10 OUTPUT POWER (dB) REFERENCE LEVEL = –2.5dBm –50 –60 –70 –107.4dBc/Hz –80 –80 –85 –90 –95 –100 –105 –110 –115 –120 –125 –130 04763-006 –135 –90 –2kHz –1kHz 65MHz 1kHz –140 –145 –150 100 2kHz Figure 6. Close-In Phase Noise at 65 MHz (1 MHz Channel Spacing) 04763-009 OUTPUT POWER (dB) TYPICAL PERFORMANCE CHARACTERISTICS 1k 10k 100k FREQUENCY OFFSET (Hz) 1M 10M Figure 9. VCO Phase Noise, 160 MHz, 1 MHz PFD, 100 kHz Loop Bandwidth Rev. A | Page 8 of 24 ADF4360-8 0 –70 –30 –40 –50 –60 –70 –110 –115 –120 –125 –135 –109.4dBc/Hz –2kHz –1kHz 160MHz 1kHz 04763-013 –140 04763-010 –90 –145 –150 100 2kHz Figure 10. Close-In Phase Noise at 160 MHz (1 MHz Channel Spacing) 1k 10k 100k FREQUENCY OFFSET (Hz) 1M 10M Figure 13. VCO Phase Noise, 400 MHz, 1 MHz PFD, 100 kHz Loop Bandwidth 0 0 –20 –30 –40 VDD = 3.3V, V VCO = 3.3V ICP = 2.5mA PFD FREQUENCY = 1MHz LOOP BANDWIDTH = 100kHz RES. BANDWIDTH = 1kHz VIDEO BANDWIDTH = 1kHz SWEEP = 4.2SECONDS AVERAGES = 20 REFERENCE LEVEL = 0dBm –10 –20 OUTPUT POWER (dB) REFERENCE LEVEL = 1dBm –10 –50 –60 –76dBc –70 –80 –30 –40 VDD = 3.3V, VVCO = 3.3V ICP = 2.5mA PFD FREQUENCY = 1MHz LOOP BANDWIDTH = 100kHz RES. BANDWIDTH = 30Hz VIDEO BANDWIDTH = 30Hz SWEEP = 1.9SECONDS AVERAGES = 20 –50 –60 –70 –103.4dBc/Hz 04763-011 –80 –90 –1.1MHz –0.55MHz 160MHz 0.55MHz –90 1.1MHz Figure 11. Reference Spurs at 160 MHz (1 MHz Channel Spacing, 100 kHz Loop Bandwidth) 04763-014 OUTPUT POWER (dB) –105 –130 –80 –2kHz –1kHz 400MHz 1kHz 2kHz Figure 14. Close-In Phase Noise at 400 MHz (1 MHz Channel Spacing) –40 0 –50 –10 –60 REFERENCE LEVEL = 0dBm –20 OUTPUT POWER (dB) –70 –80 –90 –100 –110 –120 –30 –40 VDD = 3.3V, V VCO = 3.3V ICP = 2.5mA PFD FREQUENCY = 1MHz LOOP BANDWIDTH = 100kHz RES. BANDWIDTH = 1kHz VIDEO BANDWIDTH = 1kHz SWEEP = 4.2SECONDS AVERAGES = 20 –50 –60 –77dBc –70 –80 –130 04763-012 OUTPUT POWER (dB) –80 –85 –90 –95 –100 –140 –150 100 1k 10k 100k FREQUENCY OFFSET (Hz) 1M 04763-015 OUTPUT POWER (dB) –20 –75 OUTPUT POWER (dB) REFERENCE LEVEL = 1dBm –10 VDD = 3.3V, VVCO = 3.3V ICP = 2.5mA PFD FREQUENCY = 1MHz LOOP BANDWIDTH = 100kHz RES. BANDWIDTH = 30Hz VIDEO BANDWIDTH = 30Hz SWEEP = 1.9SECONDS AVERAGES = 20 –90 10M –1.1MHz –0.55MHz 400MHz 0.55MHz Figure 15. Reference Spurs at 400 MHz (1 MHz Channel Spacing, 100 kHz Loop Bandwidth) Figure 12. Open-Loop VCO Phase Noise, L1, L2 = 18 nH Rev. A | Page 9 of 24 1.1MHz ADF4360-8 CIRCUIT DESCRIPTION REFERENCE INPUT SECTION The reference input stage is shown in Figure 16. SW1 and SW2 are normally closed switches. SW3 is normally open. When power-down is initiated, SW3 is closed, and SW1 and SW2 are opened. This ensures that there is no loading of the REFIN pin on power-down. VP HI D1 Q1 CHARGE PUMP UP U1 R DIVIDER CLR1 POWER-DOWN CONTROL NC PROGRAMMABLE DELAY 100kΩ SW2 REFIN NC CP U3 TO R COUNTER ABP1 BUFFER ABP2 CLR2 HI D2 Q2 DOWN U2 Figure 16. Reference Input Stage N DIVIDER N COUNTER The CMOS N counter allows a wide division ratio in the PLL feedback counter. The counters are specified to work when the VCO output is 400 MHz or less. To avoid confusion, this is referred to as the B counter. It makes it possible to generate output frequencies that are spaced only by the reference frequency divided by R. The VCO frequency equation is CPGND R DIVIDER N DIVIDER 04763-017 SW3 NO 04763-016 SW1 CP OUTPUT fVCO = B × f REFIN / R Figure 17. PFD Simplified Schematic and Timing (In Lock) where: MUXOUT AND LOCK DETECT fVCO is the output frequency of the VCO. B is the preset divide ratio of the binary 13-bit counter (3 to 8191). fREFIN is the external reference frequency oscillator. The output multiplexer on the ADF4360 family allows the user to access various internal points on the chip. The state of MUXOUT is controlled by M3, M2, and M1 in the function latch. The full truth table is shown in Table 7. Figure 18 shows the MUXOUT section in block diagram form. R COUNTER The 14-bit R counter allows the input reference frequency to be divided down to produce the reference clock to the phase frequency detector (PFD). Division ratios from 1 to 16,383 are allowed. DVDD DIGITAL LOCK DETECT R COUNTER OUTPUT The PFD takes inputs from the R counter and N counter ( N = BP + A) and produces an output proportional to the phase and frequency difference between them. Figure 17 is a simplified schematic. The PFD includes a programmable delay element that controls the width of the antibacklash pulse. This pulse ensures that there is no dead zone in the PFD transfer function, and minimizes phase noise and reference spurs. Two bits in the R counter latch, ABP2 and ABP1, control the width of the pulse (see Table 9). MUX MUXOUT CONTROL N COUNTER OUTPUT Rev. A | Page 10 of 24 DGND Figure 18. MUXOUT Circuit 04763-018 PFD AND CHARGE PUMP ADF4360-8 MUXOUT can be programmed for one type of lock detect. Digital lock detect is active high. When LDP in the R counter latch is set to 0, digital lock detect is set high when the phase error on three consecutive phase detector cycles is less than 15 ns. With LDP set to 1, five consecutive cycles of less than 15 ns phase error are required to set the lock detect. It stays set high until a phase error of greater than 25 ns is detected on any subsequent PD cycle. INPUT SHIFT REGISTER The ADF4360 family’s digital section includes a 24-bit input shift register, a 14-bit R counter, and an 18-bit N counter comprised of a 5-bit A counter and a 13-bit B counter. Data is clocked into the 24-bit shift register on each rising edge of CLK. The data is clocked in MSB first. Data is transferred from the shift register to one of four latches on the rising edge of LE. The destination latch is determined by the state of the two control bits (C2, C1) in the shift register. The two LSBs, DB1 and DB0, are shown in Figure 2. The correct band is chosen automatically by the band select logic at power-up or whenever the N counter latch is updated. It is important that the correct write sequence be followed at power-up. This sequence is 1. R counter latch 2. Control latch 3. N counter latch During band select, which takes five PFD cycles, the VCO VTUNE is disconnected from the output of the loop filter and connected to an internal reference voltage. 3.5 3.0 2.5 VTUNE (V) Lock Detect 2.0 1.5 1.0 The truth table for these bits is shown in Table 5. Table 6 shows a summary of how the latches are programmed. Note that the test modes latch is used for factory testing and should not be programmed by the user. 0 80 Table 5. C2 and C1 Truth Table C2 0 0 1 1 Control Bits C1 0 1 0 1 04763-019 0.5 85 90 95 100 105 FREQUENCY (MHz) 110 115 Figure 19. Frequency vs. VTUNE, ADF4360-8, L1 and L2 = 270 nH The R counter output is used as the clock for the band select logic and should not exceed 1 MHz. A programmable divider is provided at the R counter input to allow division by 1, 2, 4, or 8, and is controlled by the BSC1 bit and the BSC2 bit in the R counter latch. Where the required PFD frequency exceeds 1 MHz, the divide ratio should be set to allow enough time for correct band selection. Data Latch Control Latch R Counter N Counter (B) Test Modes Latch VCO The VCO core in the ADF4360 family uses eight overlapping bands, as shown in Figure 19, to allow a wide frequency range to be covered without a large VCO sensitivity (KV) and resultant poor phase noise and spurious performance. After band selection, normal PLL action resumes. The value of KV is determined by the value of inductors used (see the Choosing the Correct Inductance Value section). The ADF4360 family contains linearization circuitry to minimize any variation of the product of ICP and KV. The operating current in the VCO core is programmable in four steps: 2.5 mA, 5 mA, 7.5 mA, and 10 mA. This is controlled by the PC1 bit and the PC2 bit in the control latch. Rev. A | Page 11 of 24 ADF4360-8 OUTPUT STAGE If the outputs are used individually, the optimum output stage consists of a shunt inductor to VDD. Another feature of the ADF4360 family is that the supply current to the RF output stage is shut down until the part achieves lock, as measured by the digital lock detect circuitry. This is enabled by the Mute-Till-Lock Detect (MTLD) bit in the control latch. RFOUTA VCO RFOUTB BUFFER 04763-020 The RFOUTA and RFOUTB pins of the ADF4360 family are connected to the collectors of an NPN differential pair driven by buffered outputs of the VCO, as shown in Figure 20. To allow the user to optimize the power dissipation vs. the output power requirements, the tail current of the differential pair is programmable via Bits PL1 and PL2 in the control latch. Four current levels may be set: 3.5 mA, 5 mA, 7.5 mA, and 11 mA. These levels give output power levels of −9 dBm, −6 dBm, −3 dBm, and 0 dBm, respectively, using the correct shunt inductor to VDD and ac coupling into a 50 Ω load. Alternatively, both outputs can be combined in a 1 + 1:1 transformer or a 180° microstrip coupler (see the Output Matching section). Figure 20. Output Stage ADF4360-8 Rev. A | Page 12 of 24 ADF4360-8 LATCH STRUCTURE Table 6 shows the three on-chip latches for the ADF4360 family. The two LSBs decide which latch is programmed. Table 6. Latch Structure DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 RSV RSV PD2 PD1 CPI6 CPI5 CPI4 CPI3 CPI2 CPI1 PL2 PL1 MTLD CPG MUXOUT CONTROL COUNTER RESET CP THREESTATE PHASE DETECTOR POLARITY OUTPUT POWER LEVEL CURRENT SETTING 1 CP GAIN CURRENT SETTING 2 MUTE-TILLD POWERDOWN 1 POWERDOWN 2 RESERVED RESERVED CONTROL LATCH CORE POWER LEVEL CONTROL BITS DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 CP PDP M3 M2 M1 CR PC2 PC1 C2 (0) C1 (0) DB1 DB0 CP GAIN RESERVED RESERVED N COUNTER LATCH 13-BIT B COUNTER DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 RSV RSV CPG B13 B12 B11 B10 B9 B8 B7 B6 CONTROL BITS RESERVED B5 B4 B3 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 B2 B1 RSV RSV RSV RSV RSV RSV C2 (1) C1 (0) DB1 DB0 ANTIBACKLASH PULSE WIDTH DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 RSV RSV BSC2 BSC1 TMB LDP ABP2 ABP1 CONTROL BITS 14-BIT REFERENCE COUNTER R14 R13 R12 R11 R10 R9 Rev. A | Page 13 of 24 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 R8 R7 R6 R5 R4 R3 R2 R1 DB1 DB0 C2 (0) C1 (1) 04763-021 BAND SELECT CLOCK TEST MODE BIT LOCK DETECT PRECISION RESERVED RESERVED R COUNTER LATCH ADF4360-8 DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 RSV RSV PD2 PD1 CPI6 CPI5 CPI4 CPI3 CPI2 CPI1 PL2 PL1 MTLD CPG COUNTER RESET CP THREESTATE PHASE DETECTOR POLARITY OUTPUT POWER LEVEL CURRENT SETTING 1 CP GAIN CURRENT SETTING 2 MUTE-TILLD POWERDOWN 1 POWERDOWN 2 RESERVED RESERVED Table 7. Control Latch MUXOUT CONTROL CORE POWER LEVEL DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 CP PDP M3 M2 M1 CR PC2 PC1 C2 (0) C1 (0) PC2 0 0 1 1 CPI6 CPI5 CPI4 ICP (mA) CPI3 0 0 0 0 1 1 1 1 CPI2 0 0 1 1 0 0 1 1 CPI1 0 1 0 1 0 1 0 1 4.7kΩ 0.31 0.62 0.93 1.25 1.56 1.87 2.18 2.50 PDP 0 1 CP 0 1 CPG 0 1 MTLD 0 1 PL2 0 0 1 1 THESE BITS ARE NOT USED BY THE DEVICE AND ARE DON'T CARE BITS. PD2 X X 0 1 PD1 X 0 1 1 OUTPUT POWER LEVEL 0 1 0 1 CURRENT 3.5mA 5.0mA 7.5mA 11.0mA (USING TUNED LOAD) –9dBm –6dBm –3dBm 0dBm PHASE DETECTOR POLARITY NEGATIVE POSITIVE PC1 0 1 0 1 DB1 DB0 CORE POWER LEVEL 2.5mA 5mA 7.5mA 10mA COUNTER OPERATION CR 0 1 NORMAL R, A, B COUNTERS HELD IN RESET CHARGE PUMP OUTPUT NORMAL THREE-STATE CP GAIN CURRENT SETTING 1 CURRENT SETTING 2 MUTE-TIL-LOCK DETECT DISABLED ENABLED (USING 50Ω TO VVCO) –19dBm –15dBm –12dBm –9dBm MODE ASYNCHRONOUS POWER-DOWN NORMAL OPERATION ASYNCHRONOUS POWER-DOWN SYNCHRONOUS POWER-DOWN 04763-022 CE PIN 0 1 1 1 PL1 CONTROL BITS Rev. A | Page 14 of 24 M3 0 0 M2 0 0 M1 0 1 0 0 1 1 0 1 1 1 1 1 0 0 1 1 0 1 0 1 MUXOUT THREE-STATE OUTPUT DIGITAL LOCK DETECT (ACTIVE HIGH) N DIVIDER OUTPUT DVDD R DIVIDER OUTPUT NOT USED NOT USED DGND ADF4360-8 CP GAIN RESERVED RESERVED Table 8. N Counter Latch 13-BIT B COUNTER DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 RSV RSV CPG B13 B12 B11 B10 B9 B8 B7 CONTROL BITS RESERVED B6 B5 B4 B3 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 B2 B1 RSV RSV RSV RSV RSV RSV C2 (1) C1 (0) THESE BITS ARE NOT USED BY THE DEVICE AND ARE DON'T CARE BITS. B12 0 0 0 0 . . . 1 1 1 1 B11 0 0 0 0 . . . 1 1 1 1 .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... B3 0 0 0 1 . . . 1 1 1 1 B2 0 0 1 1 . . . 0 0 1 1 B1 0 1 0 1 . . . 0 1 0 1 F4 (FUNCTION LATCH) FASTLOCK ENABLE CP GAIN OPERATION 0 0 0 1 CHARGE PUMP CURRENT SETTING 1 IS PERMANENTLY USED CHARGE PUMP CURRENT SETTING 2 IS PERMANENTLY USED B COUNTER DIVIDE RATIO NOT ALLOWED NOT ALLOWED NOT ALLOWED 3 . . . 8188 8189 8190 8191 N = B; P IS PRESCALER VALUE SET IN THE CONTROL LATCH. B MUST BE GREATER THAN OR EQUAL TO A. FOR CONTINUOUSLY ADJACENT VALUES OF (N × FREF), AT THE OUTPUT, NMIN IS (P2–P). THESE BITS ARE NOT USED BY THE DEVICE AND ARE DON'T CARE BITS. Rev. A | Page 15 of 24 04763-023 B13 0 0 0 0 . . . 1 1 1 1 DB0 ADF4360-8 TEST MODE BIT LOCK DETECT PRECISION RESERVED RESERVED Table 9. R Counter Latch BAND SELECT CLOCK ANTIBACKLASH PULSE WIDTH DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 RSV BSC2 BSC1 TMB THESE BITS ARE NOT USED BY THE DEVICE AND ARE DON'T CARE BITS. LDP ABP2 ABP1 TEST MODE BIT SHOULD BE SET TO 0 FOR NORMAL OPERATION. LDP 0 1 BSC1 0 1 0 1 R13 R12 R11 R10 R14 0 0 0 0 . . . 1 1 1 1 ABP2 0 0 1 1 BSC2 0 0 1 1 R14 ABP1 0 1 0 1 ANTIBACKLASH PULSE WIDTH 3.0ns 1.3ns 6.0ns 3.0ns LOCK DETECT PRECISION THREE CONSECUTIVE CYCLES OF PHASE DELAY LESS THAN 15ns MUST OCCUR BEFORE LOCK DETECT IS SET. FIVE CONSECUTIVE CYCLES OF PHASE DELAY LESS THAN 15ns MUST OCCUR BEFORE LOCK DETECT IS SET. BAND SELECT CLOCK DIVIDER 1 2 4 8 04763-024 RSV CONTROL BITS 14-BIT REFERENCE COUNTER Rev. A | Page 16 of 24 R9 R13 0 0 0 0 . . . 1 1 1 1 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 R8 R7 R6 R5 R4 R3 R2 R1 R12 0 0 0 0 . . . 1 1 1 1 .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... R3 0 0 0 1 . . . 1 1 1 1 R2 0 1 1 0 . . . 0 0 1 1 R1 1 0 1 0 . . . 0 1 0 1 DB1 DB0 C2 (0) C1 (1) DIVIDE RATIO 1 2 3 4 . . . 16380 16381 16382 16383 ADF4360-8 POWER-UP Power-Up Sequence The correct programming sequence for the ADF4360-8 after power-up is 1. R counter latch 2. Control latch 3. N counter latch Initial Power-Up Initial power-up refers to programming the part after the application of voltage to the AVDD, DVDD, VVCO, and CE pins. On initial power-up, an interval is required between programming the control latch and programming the N counter latch. This interval is necessary to allow the transient behavior of the ADF4360-8 during initial power-up to settle. these currents have not settled to within 10% of their steadystate value, and if the N counter latch is then programmed, the VCO may not oscillate at the desired frequency, which does not allow the band select logic to choose the correct frequency band, and the ADF4360-8 may not achieve lock. If the recommended interval is inserted, and the N counter latch is programmed, the band select logic can choose the correct frequency band, and the part locks to the correct frequency. The duration of this interval is affected by the value of the capacitor on the CN pin (Pin 14). This capacitor is used to reduce the close-in noise of the ADF4360-8 VCO. The recommended value of this capacitor is 10 µF. Using this value requires an interval of ≥15 ms between the latching in of the control latch bits and latching in of the N counter latch bits. If a shorter delay is required, the capacitor can be reduced. A slight phase noise penalty is incurred by this change, which is further explained in Table 10. During initial power-up, a write to the control latch powers up the part, and the bias currents of the VCO begin to settle. If Table 10. CN Capacitance vs. Interval and Phase Noise Open-Loop Phase Noise @ 10 kHz Offset (L1 and L2 = 18.0 nH) −100 dBc/Hz −99 dBc/Hz Open-Loop Phase Noise @ 10 kHz Offset (L1 and L2 = 110.0 nH) −97 dBc/Hz −96 dBc/Hz Open-Loop Phase Noise @ 10 kHz Offset (L1 and L2 = 560.0 nH) −99 dBc/Hz −98 dBc/Hz POWER-UP CLOCK DATA R COUNTER LATCH DATA CONTROL LATCH DATA N COUNTER LATCH DATA LE REQUIRED INTERVAL CONTROL LATCH WRITE TO N COUNTER LATCH WRITE Figure 21. ADF4360-8 Power-Up Timing Rev. A | Page 17 of 24 04763-033 CN Value 10 µF 440 nF Recommended Interval Between Control Latch and N Counter Latch ≥15 ms ≥ 600 µs ADF4360-8 Hardware Power-Up/Power-Down Software Power-Up/Power-Down If the part is powered down via the hardware (using the CE pin) and powered up again without any change to the N counter register during power-down, the part locks at the correct frequency, because the part is already in the correct frequency band. The lock time depends on the value of capacitance on the CN pin, which is <15 ms for 10 µF capacitance. The smaller capacitance of 440 nF on this pin enables lock times of <600 µs. If the part is powered down via the software (using the control latch) and powered up again without any change to the N counter latch during power-down, the part locks at the correct frequency, because the part is already in the correct frequency band. The lock time depends on the value of capacitance on the CN pin, which is <15 ms for 10 µF capacitance. The smaller capacitance of 440 nF on this pin enables lock times of <600 µs. The N counter value cannot be changed while the part is in power-down, since the part may not lock to the correct frequency on power-up. If it is updated, the correct programming sequence for the part after power-up is the R counter latch, followed by the control latch, and finally the N counter latch, with the required interval between the control latch and N counter latch, as described in the Initial Power-Up section. The N counter value cannot be changed while the part is in power-down, because the part may not lock to the correct frequency on power-up. If it is updated, the correct programming sequence for the part after power-up is to the R counter latch, followed by the control latch, and finally the N counter latch, with the required interval between the control latch and N counter latch, as described in the Initial Power-Up section. Rev. A | Page 18 of 24 ADF4360-8 CONTROL LATCH Charge Pump Currents With (C2, C1) = (0,0), the control latch is programmed. Table 7 shows the input data format for programming the control latch. CPI3, CPI2, and CPI1 in the ADF4360 family determine Current Setting 1. Power-Down CPI6, CPI5, and CPI4 determine Current Setting 2. See the truth table in Table 7. DB21 (PD2) and DB20 (PD1) provide programmable powerdown modes. In the programmed asynchronous power-down, the device powers down immediately after latching a 1 into Bit PD1, with the condition that PD2 has been loaded with a 0. In the programmed synchronous power-down, the device powerdown is gated by the charge pump to prevent unwanted frequency jumps. Once the power-down is enabled by writing a 1 into Bit PD1 (on the condition that a 1 has also been loaded to PD2), the device goes into power-down on the second rising edge of the R counter output, after LE goes high. When the CE pin is low, the device is immediately disabled, regardless of the state of PD1 or PD2. Output Power Level Bits PL1 and PL2 set the output power level of the VCO. See the truth table in Table 7. Mute-Till-Lock Detect DB11 of the control latch in the ADF4360 family is the MuteTill-Lock Detect bit. This function, when enabled, ensures that the RF outputs are not switched on until the PLL is locked. CP Gain DB10 of the control latch in the ADF4360 family is the Charge Pump Gain bit. When it is programmed to 1, Current Setting 2 is used. When programmed to 0, Current Setting 1 is used. When a power-down is activated (either synchronous or asynchronous mode), the following events occur: Charge Pump Three-State • All active dc current paths are removed. • This bit puts the charge pump into three-state mode when programmed to a 1. It should be set to 0 for normal operation. The R, N, and timeout counters are forced to their load state conditions. Phase Detector Polarity • The charge pump is forced into three-state mode. • The digital lock detect circuitry is reset. • The RF outputs are de-biased to a high impedance state. • The reference input buffer circuitry is disabled. • The input register remains active and capable of loading and latching data. The PDP bit in the ADF4360 family sets the phase detector polarity. The positive setting enabled by programming a 1 is used when using the on-chip VCO with a passive loop filter or with an active non-inverting filter. It can also be set to 0, which is required if an active inverting loop filter is used. MUXOUT Control The on-chip multiplexer is controlled by M3, M2, and M1. See the truth table in Table 7. Counter Reset DB4 is the counter reset bit for the ADF4360 family. When this is 1, the R counter and the A, B counters are reset. For normal operation, this bit should be 0. Core Power Level PC1 and PC2 set the power level in the VCO core. The recommended setting is 5 mA. See the truth table in Table 7. Rev. A | Page 19 of 24 ADF4360-8 N COUNTER LATCH R COUNTER LATCH Table 8 shows the input data format for programming the N counter latch. With (C2, C1) = (0, 1), the R counter latch is programmed. Table 9 shows the input data format for programming the R counter latch. Reserved Bits R Counter DB2 to DB7 are spare bits and have been designated as reserved. They should be programmed to 0. R1 to R14 set the counter divide ratio. The divide range is 1 (00...001) to 16383 (111...111). B Counter Latch B13 to B1 program the B counter. The divide range is 3 (00...0011) to 8191 (11...111). Antibacklash Pulse Width Overall Divide Range Lock Detect Precision The overall VCO feedback divide range is defined by B. DB18 is the lock detect precision bit. This bit sets the number of reference cycles with less than 15 ns phase error for entering the locked state. With LDP at 1, five cycles are taken; with LDP at 0, three cycles are taken. DB16 and DB17 set the antibacklash pulse width. CP Gain DB21 of the N counter latch in the ADF4360 family is the charge pump gain bit. When it is programmed to 1, Current Setting 2 is used. When programmed to 0, Current Setting 1 is used. This bit can also be programmed through DB10 of the control latch. The bit always reflects the latest value written to it, whether this is through the control latch or the N counter latch. Test Mode Bit DB19 is the test mode bit (TMB) and should be set to 0. With TMB = 0, the contents of the test mode latch are ignored and normal operation occurs, as determined by the contents of the control latch, R counter latch, and N counter latch. Note that test modes are for factory testing only and should not be programmed by the user. Band Select Clock These bits set a divider for the band select logic clock input. The output of the R counter is, by default, the value used to clock the band select logic; if this value is too high (>1 MHz), a divider can be switched on to divide the R counter output to a smaller value (see Table 9). Reserved Bits DB23 to DB22 are spare bits that have been designated as reserved. They should be programmed to 0. Rev. A | Page 20 of 24 ADF4360-8 12 CHOOSING THE CORRECT INDUCTANCE VALUE 10 8 6 4 2 0 The lowest center frequency of oscillation possible is approximately 65 MHz, which is achieved using 560 nH inductors. This relationship can be expressed by FO = 0 2π 9.3 pF(0.9 nH + L EXT ) 450 400 350 300 250 200 150 200 300 400 INDUCTANCE (nH) 04763-025 200 300 400 INDUCTANCE (nH) 500 600 6 10µF FOX 801BE-160 16MHz Figure 22. Output Center Frequency vs. External Inductor Value LOCK DETECT VVDD 21 2 23 20 VVCO DVDD AVDD CE MUXOUT VTUNE 7 14 CN CP 24 1nF 1nF 16 REFIN 51Ω 15kΩ 680pF 6.8kΩ ADF4360-8 18 DATA SPI-COMPATIBLE SERIAL BUS The approximate value of capacitance at the midpoint of the center band of the VCO is 9.3 pF, and the approximate value of internal inductance due to the bond wires is 0.9 nH. The VCO sensitivity is a measure of the frequency change vs. the tuning voltage. It is a very important parameter for the low-pass filter. Figure 23 shows a graph of the tuning sensitivity (in MHz/V) vs. the inductance (nH). It can be seen that as the inductance increases, the sensitivity decreases. This relationship can be derived from the equation above; that is, since the inductance has increased, the change in capacitance from the varactor has less of an effect on the frequency. Rev. A | Page 21 of 24 VVCO 19 LE 12 CC 56nH 13 RSET 1nF 56nH 100pF RFOUTA 4 4.7kΩ CPGND 1 22nF 47pF 17 CLK AGND DGND L1 L2 RF OUTB 5 3 8 11 22 15 9 10 68nH 100pF 470Ω 470Ω 68nH 04763-027 50 100 600 Figure 24 shows the ADF4360-8 used as a fixed frequency LO at 200 MHz. The low-pass filter was designed using ADIsimPLL for a channel spacing of 2 MHz and an open-loop bandwidth of 100 kHz. The maximum PFD frequency of the ADF4360-8 is 8 MHz. Since using a larger PFD frequency allows the use of a smaller N, the in-band phase noise is reduced to as low as possible, −109 dBc/Hz. The typical rms phase noise (100 Hz to 100 kHz) of the LO in this configuration is 0.09°. The reference frequency is from a 16MHz TCXO from Fox; thus, an R value of 2 is programmed. Taking into account the high PFD frequency and its effect on the band select logic, the band select clock divider is enabled. In this case, a value of 8 is chosen. A very simple shunt inductor and dc-blocking capacitor complete the RF output stage. VVCO 0 500 Figure 23. Tuning Sensitivity (in MHz/V) vs. Inductance (nH) 100 0 100 FIXED FREQUENCY LO 1 where FO is the center frequency and LEXT is the external inductance. FREQUENCY (MHz) 04763-026 The ADF4360-8 can be used at many different frequencies simply by choosing the external inductors to give the correct output frequency. Figure 22 shows a graph of both minimum and maximum frequency vs. the external inductor value. The correct inductor should cover the maximum and minimum frequencies desired. The inductors used are 0603 CS or 0805 CS type from Coilcraft. To reduce mutual coupling, the inductors should be placed at right angles to one another. SENSITIVITY (MHz/V) APPLICATIONS Figure 24. Fixed Frequency LO ADF4360-8 INTERFACING ADSP-2181 Interface The ADF4360 family has a simple SPI®-compatible serial interface for writing to the device. CLK, DATA, and LE control the data transfer. When LE goes high, the 24 bits that have been clocked into the appropriate register on each rising edge of CLK are transferred to the appropriate latch. See Figure 2 for the timing diagram and Table 5 for the latch truth table. Figure 26 shows the interface between the ADF4360 family and the ADSP-21xx digital signal processor. The ADF4360 family needs a 24-bit serial word for each latch write. The easiest way to accomplish this using the ADSP-21xx family is to use the autobuffered transmit mode of operation with alternate framing. This provides a means for transmitting an entire block of serial data before an interrupt is generated. The maximum allowable serial clock rate is 20 MHz. This means that the maximum update rate possible is 833 kHz, or one update every 1.2 µs. This is more than adequate for systems that have typical lock times in hundreds of microseconds. SCLOCK MOSI TFS ADSP-21xx ADuC812 Interface I/O PORTS LE ADF4360-x CE MUXOUT (LOCK DETECT) 04763-029 Figure 25 shows the interface between the ADF4360 family and the ADuC812 MicroConverter®. Since the ADuC812 is based on an 8051 core, this interface can be used with any 8051-based microcontrollers. The MicroConverter is set up for SPI master mode with CPHA = 0. To initiate the operation, the I/O port driving LE is brought low. Each latch of the ADF4360 family needs a 24-bit word, which is accomplished by writing three 8-bit bytes from the MicroConverter to the device. After the third byte has been written, the LE input should be brought high to complete the transfer. SCLK SDATA Figure 26. ADSP-21xx to ADF4360-x Interface Set up the word length for 8 bits and use three memory locations for each 24-bit word. To program each 24-bit latch, store the 8-bit bytes, enable the autobuffered mode, and write to the transmit register of the DSP. This last operation initiates the autobuffer transfer. PCB DESIGN GUIDELINES FOR CHIP SCALE PACKAGE SCLOCK MOSI ADuC812 I/O PORTS The leads on the chip scale package (CP-24) are rectangular. The printed circuit board pad for these should be 0.1 mm longer than the package lead length and 0.05 mm wider than the package lead width. The lead should be centered on the pad to ensure that the solder joint size is maximized. SCLK SDATA LE ADF4360-x CE 04763-028 MUXOUT (LOCK DETECT) Figure 25. ADuC812 to ADF4360-x Interface I/O port lines on the ADuC812 are also used to control powerdown (CE input) and detect lock (MUXOUT configured as lock detect and polled by the port input). When operating in the described mode, the maximum SCLOCK rate of the ADuC812 is 4 MHz. This means that the maximum rate at which the output frequency can be changed is 166 kHz. The bottom of the chip scale package has a central thermal pad. The thermal pad on the printed circuit board should be at least as large as this exposed pad. On the printed circuit board, there should be a clearance of at least 0.25 mm between the thermal pad and the inner edges of the pad pattern to ensure that shorting is avoided. Thermal vias may be used on the printed circuit board thermal pad to improve thermal performance of the package. If vias are used, they should be incorporated into the thermal pad at 1.2 mm pitch grid. The via diameter should be between 0.3 mm and 0.33 mm, and the via barrel should be plated with 1 ounce of copper to plug the via. The user should connect the printed circuit thermal pad to AGND. This is internally connected to AGND. Rev. A | Page 22 of 24 ADF4360-8 There are a number of ways to match the output of the ADF4360-8 for optimum operation; the most basic is to use a 50 Ω resistor to VVCO. A dc bypass capacitor of 100 pF is connected in series, as shown in Figure 27. Because the resistor is not frequency dependent, this provides a good broadband match. The output power in the circuit below typically gives −9 dBm output power into a 50 Ω load. VVCO 51Ω The recommended value of this inductor changes with the VCO center frequency. A graph of the optimum inductor value vs. frequency is shown in Figure 29. 300 250 INDUCTANCE (nH) OUTPUT MATCHING 200 150 100 50Ω 50 0 Figure 27. Simple ADF4360-8 Output Stage 0 A better solution is to use a shunt inductor (acting as an RF choke) to VVCO. This gives a better match and, therefore, more output power. Experiments have shown that the circuit shown in Figure 28 provides an excellent match to 50 Ω over the operating range of the ADF4360-8. This gives approximately 0 dBm output power across the specific frequency range of the ADF4360-8 using the recommended shunt inductor, followed by a 100 pF dc blocking capacitor. 200 300 CENTRE FREQUENCY (MHz) 400 5000 Both complementary architectures can be examined using the EVAL-ADF4360-8EB1 evaluation board. If the user does not need the differential outputs available on the ADF4360-8, the user should either terminate the unused output or combine both outputs using a balun. Alternatively, instead of the LC balun, both outputs may be combined using a 180° rat-race coupler. L 04763-031 100pF 50Ω 100 Figure 29. Optimum ADF4360-8 Shunt Inductor VVCO RFOUT 04763-032 RFOUT 04763-030 100pF Figure 28. Optimum ADF4360-8 Output Stage Rev. A | Page 23 of 24 ADF4360-8 OUTLINE DIMENSIONS 0.60 MAX 4.00 BSC SQ PIN 1 INDICATOR 0.60 MAX TOP VIEW 0.50 BSC 3.75 BSC SQ 0.50 0.40 0.30 1.00 0.85 0.80 12° MAX PIN 1 INDICATOR 19 18 24 1 *2.45 EXPOSED PAD 2.30 SQ 2.15 (BOTTOMVIEW) 13 12 7 0.80 MAX 0.65 TYP 6 0.23 MIN 2.50 REF 0.05 MAX 0.02 NOM SEATING PLANE 0.30 0.23 0.18 0.20 REF COPLANARITY 0.08 *COMPLIANT TO JEDEC STANDARDS MO-220-VGGD-2 EXCEPT FOR EXPOSED PAD DIMENSION Figure 30. 24-Lead Lead Frame Chip Scale Package [VQ_LFCSP] 4 x 4 mm Body, Very Thin Quad (CP-24-2) Dimensions shown in millimeters ORDERING GUIDE Model Temperature Range Frequency Range Package Option ADF4360-8BCP ADF4360-8BCPRL ADF4360-8BCPRL7 ADF4360-8BCPZ1 ADF4360-8BCPZRL1 ADF4360-8BCPZRL71 EVAL-ADF4360-8EB1 −40°C to +85°C −40°C to +85°C −40°C to +85°C −40°C to +85°C −40°C to +85°C −40°C to +85°C 65 MHz to 400 MHz 65 MHz to 400 MHz 65 MHz to 400 MHz 65 MHz to 400 MHz 65 MHz to 400 MHz 65 MHz to 400 MHz CP-24-1 CP-24-1 CP-24-1 CP-24-1 CP-24-1 CP-24-1 Evaluation Board 1 Z = Pb-free part. Purchase of licensed I2C components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the purchaser under the Philips I2C Patent Rights to use these components in an I2C system, provided that the system conforms to the I2C Standard Specification as defined by Philips. © 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D04763–0–1/05(A) Rev. A | Page 24 of 24