SNAS654A March   2015  – July 2016 LMX2571

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Reference Oscillator Input
      2. 7.3.2  R-Dividers and Multiplier
      3. 7.3.3  PLL Phase Detector and Charge Pump
      4. 7.3.4  PLL N-Divider and Fractional Circuitry
      5. 7.3.5  Partially Integrated Loop Filter
      6. 7.3.6  Low-Noise, Fully Integrated VCO
      7. 7.3.7  External VCO Support
      8. 7.3.8  Programmable RF Output Divider
      9. 7.3.9  Programmable RF Output Buffer
      10. 7.3.10 Integrated TX, RX Switch
      11. 7.3.11 Powerdown
      12. 7.3.12 Lock Detect
      13. 7.3.13 FSK Modulation
      14. 7.3.14 FastLock
      15. 7.3.15 Register Readback
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation Mode
      2. 7.4.2 Duplex Mode
      3. 7.4.3 FSK Mode
    5. 7.5 Programming
      1. 7.5.1 Recommended Initial Power on Programming Sequence
      2. 7.5.2 Recommended Sequence for Changing Frequencies
    6. 7.6 Register Maps
      1. 7.6.1  R60 Register (offset = 3Ch) [reset = 4000h]
      2. 7.6.2  R58 Register (offset = 3Ah) [reset = C00h]
      3. 7.6.3  R53 Register (offset = 35h) [reset = 2802h]
      4. 7.6.4  R47 Register (offset = 2Fh) [reset = 0h]
      5. 7.6.5  R46 Register (offset = 2Eh) [reset = 1Ah]
      6. 7.6.6  R42 Register (offset = 2Ah) [reset = 210h]
      7. 7.6.7  R41 Register (offset = 29h) [reset = 810h]
      8. 7.6.8  R40 Register (offset = 28h) [reset = 101Ch]
      9. 7.6.9  R39 Register (offset = 27h) [reset = 11F0h]
      10. 7.6.10 R35 Register (offset = 23h) [reset = 647h]
      11. 7.6.11 R34 Register (offset = 22h) [reset = 1000h]
      12. 7.6.12 R33 Register (offset = 21h) [reset = 0h]
      13. 7.6.13 R25 to R32 Register (offset = 19h to 20h) [reset = 0h]
      14. 7.6.14 R24 Register (offset = 18h) [reset = 10h]
      15. 7.6.15 R23 Register (offset = 17h) [reset = 10A4h]
      16. 7.6.16 R22 Register (offset = 16h) [reset = 8584h]
      17. 7.6.17 R21 Register (offset = 15h) [reset = 101h]
      18. 7.6.18 R20 Register (offset = 14h) [reset = 28h]
      19. 7.6.19 R19 Register (offset = 13h) [reset = 0h]
      20. 7.6.20 R18 Register (offset = 12h) [reset = 0h]
      21. 7.6.21 R17 Register (offset = 11h) [reset = 0h]
      22. 7.6.22 R9 to R16 Register (offset = 9h to 10h) [reset = 0h]
      23. 7.6.23 R8 Register (offset = 8h) [reset = 10h]
      24. 7.6.24 R7 Register (offset = 7h) [reset = 10A4h]
      25. 7.6.25 R6 Register (offset = 6h) [reset = 8584h]
      26. 7.6.26 R5 Register (offset = 5h) [reset = 101h]
      27. 7.6.27 R4 Register (offset = 4h) [reset = 28h]
      28. 7.6.28 R3 Register (offset = 3h) [reset = 0h]
      29. 7.6.29 R2 Register (offset = 2h) [reset = 0h]
      30. 7.6.30 R1 Register (offset = 1h) [reset = 0h]
      31. 7.6.31 R0 Register (offset = 0h) [reset = 3h]
  8. Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  Direct Digital FSK Modulation
      2. 8.1.2  Frequency and Output Port Switching with TrCtl Pin
      3. 8.1.3  OSCin Configuration
      4. 8.1.4  Register R0 F1F2_INIT, F1F2_MODE usage
      5. 8.1.5  FastLock with External VCO
      6. 8.1.6  OSCin Slew Rate
      7. 8.1.7  RF Output Buffer Power Control
      8. 8.1.8  RF Output Buffer Type
      9. 8.1.9  MULT Multiplier
      10. 8.1.10 Integrated VCO
    2. 8.2 Typical Applications
      1. 8.2.1 Synthesizer Duplex Mode
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Synthesizer Duplex Mode Application Curves
      2. 8.2.2 PLL Duplex Mode
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 PLL Duplex Mode Application Curves
      3. 8.2.3 Synthesizer/PLL Duplex Mode
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 Synthesizer/PLL Duplex Mode Application Curves
    3. 8.3 Do's and Don'ts
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted) (1)
MIN MAX UNIT
VCC Power supply voltage –0.3 3.6 V
VIO IO supply voltage –0.3 3.6 V
VIN IO input voltage VCC + 0.3 V
VCP Charge pump supply voltage 5.25 V
TJ Junction temperature 150 °C
TSTG Storage temperature –65 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±1500 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±500
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
VCC Power supply voltage 3.15 3.45 V
VIO IO supply voltage VCC V
VCP Charge pump supply voltage PLL mode (external VCO) 5 V
Synthesizer mode (internal VCO) VCC 5
TA Ambient temperature –40 85 °C
TJ Junction temperature 125 °C

6.4 Thermal Information

THERMAL METRIC(1) LMX2571 UNIT
WQFN (NJK)
36 PINS
RθJA Junction-to-ambient thermal resistance 32.9 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 14.5 °C/W
RθJB Junction-to-board thermal resistance 6.3 °C/W
ψJT Junction-to-top characterization parameter 0.2 °C/W
ψJB Junction-to-board characterization parameter 6.3 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance 2.0 °C/W
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

6.5 Electrical Characteristics

3.15 V ≤ VCC ≤ 3.45 V, VIO = VCC, –40 °C ≤ TA ≤ 85 °C, except as specified. Typical values are at VCC = VIO = 3.3 V, VCP = 3.3 V or 5 V in synthesizer mode, VCP = 5 V in PLL mode, TA = 25 °C.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
CURRENT CONSUMPTION
ICC Total current in synthesizer mode (internal VCO) fOUT = 480 MHz
SE OSCin
Configuration A(2) 39 mA
Configuration B(3) 44
Configuration C(4) 46
Configuration D(5) 51
IPLL Total current in PLL mode (external VCO) Configuration E(6) 9
Configuration F(7) 15
Configuration G(8) 21
ICCPD Power down current CE = 0V or POWERDOWN bit = 1
VCC = 3.3 V, Push-pull output
0.9
OSCIN REFERENCE INPUT
fOSCin OSCin frequency range Single-ended or differential input 10 150 MHz
VOSCin OSCin input voltage(9) Single-ended input 1.4 3.3 V
Differential input 0.15 1.5
CRYSTAL REFERENCE INPUT
fXTAL Crystal frequency range Fundamental model, ESR < 200 Ω 10 40 MHz
CIN OSCin input capacitance 1 pF
MULT
fMULTin MULT input frequency MULT > Pre-divider
Not supported with crystal reference input
10 30 MHz
fMULTout MULT output frequency 60 130 MHz
PLL
fPD Phase detector frequency 130 MHz
KPD Charge pump current(10) Programmable minimum value Internal charge pump 312.5 µA
5-V charge pump 625
Per programmable step Internal charge pump 312.5
5-V charge pump 625
Programmable maximum value Internal charge pump 7187.5
5-V charge pump 6875
PNPLL_1/f Normalized PLL 1/f noise(11) At maximum charge pump current Internal charge pump –124 dBc/Hz
5-V charge pump –120
PNPLL_Flat Normalized PLL noise floor(11) Internal charge pump –231 dBc/Hz
5-V charge pump –226
fRFin External VCO input frequency(1) EXTVCO_CHDIV=1 100 2000 MHz
EXTVCO_CHDIV=8,10 100 1900
EXTVCO_CHDIV=2,3,4,5,6,7,9 100 1400
PRFin External VCO input power 0.1 GHz ≤ fRFin < 1 GHz –10 dBm
1 GHz ≤ fRFin ≤ 1.4 GHz –5
1.4 GHz < fRFin ≤ 2 GHz 0
VCO
fVCO VCO frequency 4300 5376 MHz
KVCO VCO gain(12) fVCO = 4800 MHz 56 MHz/V
| ΔTCL | Allowable temperature drift(13) VCO not being re-calibrated, –40 °C ≤ TA ≤ 85 °C 125 °C
tVCOCal VCO calibration time fOSCin = fPD = 100 MHz 140 µs
PNVCO Open loop VCO phase noise fOUT = 480 MHz 100 Hz offset –32.4 dBc/Hz
1 kHz offset –62.3
10 kHz offset –92.1
100 kHz offset –121.1
1 MHz offset –144.5
10 MHz offset –156.8
RF OUTPUT
fOUT RF output frequency Synthesizer mode 10 1344 MHz
PLL mode, RF output from buffer 10 1400
PTX, PRX RF output power fOUT = 480 MHz Power control bit = 6 0 dBm
H2RFout Second harmonic –25 dBc
DIGITAL FSK MODULATION
FSKLevel FSK level(14) FSK PIN mode 2 8
FSKBaud FSK baud rate(15) Loop bandwidth = 200 kHz 100 kSPs
FSKDev FSK deviation Configuration H(16) ±39 kHz
DIGITAL INTERFACE
VIH High level input voltage 1.4 VIO V
VIL Low level input voltage 0.4 V
IIH High level input current VIH = 1.75 V –25 25 µA
IIL Low level input current VIL = 0 V –25 25 µA
VOH High level output voltage IOH = 500 µA 2 V
VOL Low level output voltage IOL = –500 µA 0 0.4 V
(1) For external VCO frequencies above 1.4 GHz, there are restrictions on the output divider and register R70 needs to be programmed to 0x046110.
(2) fOSCin = 19.44 MHz, MULT = 1, Prescaler = 4, fPD = 19.44 MHz, one RF output, output type = push pull, output power = –3 dBm
(3) fOSCin = 19.44 MHz, MULT = 1, Prescaler = 2, fPD = 19.44 MHz, one RF output, output type = push pull, output power = –3 dBm
(4) fOSCin = 19.44 MHz, MULT = 5, Prescaler = 2, fPD = 19.44 MHz, one RF output, output type = push pull, output power = –3 dBm
(5) fOSCin = 19.44 MHz, MULT = 5, Prescaler = 2, fPD = 97.2 MHz, one RF output, output type = push pull, output power = –3 dBm
(6) fOSCin = 19.44 MHz, MULT = 1, fPD = 19.44 MHz, output from VCO
(7) fOSCin = 19.44 MHz, MULT = 1, fPD = 19.44 MHz, one RF output, output type = push pull, output power = –3 dBm
(8) fOSCin = 19.44 MHz, MULT = 1, fPD = 19.44 MHz, two RF outputs, output type = push pull, output power = –3 dBm
(9) See OSCin Configuration for definition of OSCin input voltage.
(10) This is referring to the total base charge pump current. In PLL mode, this is equal to EXTVCO_CP_IDN + EXTVCO_CP_IUP. In synthesizer mode, this is equal to CP_IDN + CP_IUP. See Table 6, Table 7 and Table 8 for details.
(11) Measured with a clean OSCin signal with a high slew rate using a wide loop bandwidth. The noise metrics model the PLL noise for an infinite loop bandwidth as:
PLL_Total = 10 * log[10(PLL_Flat / 10) + 10(PLL_Flicker / 10)]
PLL_Flat = PN1Hz + 20 * log(N) + 10 * log(fPD)
PLL_Flicker = PN10kHz – 10 * log(Offset / 10 kHz) + 20 * log(fOUT / 1 GHz)
(12) The VCO gain changes as a function of the VCO core and frequency. See Integrated VCO for details.
(13) Not tested in production. Ensured by characterization. Allowable temperature drift refers to programming the device at an initial temperature and allowing this temperature to drift WITHOUT reprogramming the device, and still have the device stay in lock. This change could be up or down in temperature and the specification does not apply to temperatures that go outside the recommended operating temperatures of the device.
(14) The data showed here simply specifies the range of discrete FSK level that is supported in PIN mode. PIN mode supports 2-, 4- and 8-level of FSK modulation. If arbitrary level of FSK modulation is desired, use FSK SPI™ FAST mode or FSK I2S mode. See Direct Digital FSK Modulation for details.
(15) The baud rate is limited by the loop bandwidth of the PLL loop. As a general rule of thumb, it is desirable to have the loop bandwidth at least twice the baud rate.
(16) fPD = 100 MHz, DEN = 224, CHDIV1 = 5, CHDIV2 = 2, Prescaler = 2, FSK step value = 32716, 32819. The maximum achievable frequency deviation depends on the configuration, see Direct Digital FSK Modulation for details.

6.6 Timing Requirements

3.15 V ≤ VCC ≤ 3.45 V, VIO = VCC, –40 °C ≤ TA ≤ 85 °C, except as specified. Typical values are at VCC = VIO = 3.3 V, TA = 25 °C.
MIN NOM MAX UNIT
MICROWIRE TIMING
tES Clock to enable low time See Figure 1 5 ns
tCS Data to clock setup time 2 ns
tCH Data to clock hold time 2 ns
tCWH Clock pulse width high 5 ns
tCWL Clock pulse width low 5 ns
tCES Enable to clock setup time 5 ns
tEWH Enable pulse width high 2 ns
LMX2571 7_uWireTim_SNAS654.gif Figure 1. MICROWIRE Timing Diagram

There are several other considerations for programming:

  • A slew rate of at least 30 V/µs is recommended for the CLK, DATA and LE. The same apply for other digital control signals such as FSK_D[0:2] and FSK_DV signals.
  • The DATA is clocked into a shift register on each rising edge of the CLK signal. On the rising edge of the LE signal, the data is sent from the shift register to an active register.
  • The LE pin may be held high after programming, causing the LMX2571 to ignore clock pulses.
  • When CLK or DATA lines are shared between devices, it is recommended to divide down the voltage to the CLK, DATA, and LE pins closer to the minimum voltage. This provides better noise immunity.
  • If the CLK and DATA lines are toggled while the VCO is in lock, as is sometimes the case when these lines are shared with other parts, the phase noise may be degraded during the time of this programming.

6.7 Typical Characteristics

at TA = 25 °C (unless otherwise noted0
LMX2571 7_Typ200M_SNAS654.png
OSCin = 19.44 MHz fOUT = 200 MHz Synthesizer mode
Figure 2. Typical Close Loop Phase Noise
LMX2571 7_Typ900M_SNAS654.png
OSCin = 19.44 MHz fOUT = 900 MHz Synthesizer mode
Figure 4. Typical Close Loop Phase Noise
LMX2571 7_4FSK_SNAS654.png
FSKBaud = 4.8 kSPS FSK PIN mode
Figure 6. 4FSK Direct Digital Modulation
LMX2571 7_Output_SNAS654.png
Switching between int. and ext. VCO as well as Tx and Rx port
Figure 8. Output Port and VCO Switching
LMX2571 7_Fin_SNAS654.png
Start: 100 MHz Stop: 2000 MHz
Figure 10. Fin input impedance
LMX2571 D001_SNAS654.gif
fOUT = 1228.8 MHz fPD = 122.88 MHz Synthesizer mode
Figure 12. Normalized PLL 1/f Noise and Noise Floor
LMX2571 7_Typ500M_SNAS654.png
OSCin = 19.44 MHz fOUT = 500 MHz Synthesizer mode
Figure 3. Typical Close Loop Phase Noise
LMX2571 7_Typ1200M_SNAS654.png
OSCin = 19.44 MHz fOUT = 1200 MHz Synthesizer mode
Figure 5. Typical Close Loop Phase Noise
LMX2571 7_FM_SNAS654.png
Reference clock is a FM modulated signal with fMOD = 2.4 kHz
Figure 7. FM Modulation via Reference Clock
LMX2571 7_FastLock_SNAS654.png
Freq. jump = 50 MHz LBW = 4 kHz PLL mode
Figure 9. FastLock with SPST Switch
LMX2571 7_OSCin_SNAS654.png
Start: 10 MHz Stop: 300 MHz
Figure 11. OSCin input impedance
LMX2571 D002_SNAS654.gif
fOUT = 430.08 MHz fPD = 61.44 MHz PLL mode
Figure 13. Normalized PLL 1/f Noise and Noise Floor