LMX2572RHAR

LMX2572RHAR

Part Number: LMX2572RHAR

Manufacturer: Texas Instruments

Description: IC FREQ SYNTHESIZER RF 40VQFN

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Texas Instruments
Product Category: Phase Locked Loops – PLL
RoHS:  Details
Si
– 40 C
+ 85 C
SMD/SMT
VQFN-40
Reel
Brand: Texas Instruments
Features: Integrated VCO , FSK modulation, Flexible ramp generation, Integer-Boundary Spurs (IBS) removal, In
Product Type: PLLs – Phase Locked Loops
Series: LMX2572

LMX2572RHAR Description

A wideband synthesizer with outstanding performance and low power consumption, the LMX2572 can produce any frequency between 12.5 MHz and 6.4 GHz without needing an internal doubler. The PLL needs only 75 mA from a single 3.3-V supply to deliver excellent performance. The LMX2572 is capable of FSK modulation, making it suitable for wireless microphones and digital mobile radios (DMR). These include discrete-level FSK and pulse-shaping FSK. Programming or pins can be used to create direct digital FSK modulation. Users can synchronize the output of multiple devices using the LMX2572, and it also supports applications that require a deterministic delay between input and output.

To correct for delay mismatch on the board or between devices, the LMX2572 can modify the phase with precise granularity. A frequency ramp generator can manually or automatically generate up to two ramp segments for maximum adaptability. Thanks to the fast calibration process, the user can change frequencies faster than 20 milliseconds. Because it can also generate or repeat SYSREF, for timing high-speed data converters, the LMX2572 is a fantastic low-power, low-noise clock source. A fine delay adjustment is available in this configuration to consider board trace delay variations. There is no need for onboard low-noise LDOs because the LMX2572 incorporates LDOs from a single 3.3-V supply.

LMX2572RHAR Features

  • 5 MHz to 6.4 GHz as the output frequency
  • PLL merit figure: -232 dBc/Hz.
  • PLL 1/f noise normalized: -123.5 dBc/Hz.
  • Fractional-N divider in 32 bits.
  • With the help of a programmable input multiplier, remove integer boundary spurs.
  • Output phase synchronization amongst many devices.
  • Support for the programmable delay JESD204B SYSREF.
  • Ramp and chirp functionalities are supported.
  • FSK direct digital modulation support.
  • Two outputs with configurable power level differentials.
  • 20 s is a quick VCO calibration speed.
  • A solitary 3-V to a 3.5-V power supply.

LMX2572RHAR Applications

  • Low Power Radio Communication Systems
  • Satellite Communication
  • Wireless Microphones
  • Propriety Wireless Connectivity

Detailed Description

VCO and output divider built into a wideband frequency synthesizer, the LMX2572 has low power consumption and high performance. With the help of the output divider and the VCO’s operating range of 3.2 to 6.4 GHz, any frequency between 12.5 MHz and 6.4 GHz can be produced. For flexible frequency planning, there are two dividers and a multiplier in the input path. By relocating the frequencies from the integer boundary, the multiplier also permits the reduction of spurs.

The PLL has a configurable delta-sigma modulator up to the fourth order and is a fractional-N PLL. The 32-bit programmable fractional denominator may readily provide small frequency steps below the 1-Hz precision. The same fractions, like 1/3 and 7/1000, can also be calculated using the denominator, among many other fractions. For applications requiring a predictable or programmable phase, the OSCin and RFout pin relationships can be made deterministic using the SYNC pin.  Once completed, By incrementally dividing the fractional denominator by the VCO time, the phase can be changed.

For applications where the frequency needs to be swept or altered suddenly, the ultra-fast VCO calibration is perfect. The frequency can either be manually chosen or configured to ramp and chirp on the device. A differential SYSREF output that can be a single pulse, a sequence of pulses, or an ongoing stream of pulses can be produced utilizing the RFoutB output as part of the JESD204B support. These pulses have a delay that can be adjusted and synchronized with the RFoutA signal.

The FSK generator is perfect for supporting pulse-shaped FSK modulation, such as GFSK, because it supports FSK production in discrete 2-, 4-, or 8-level FSK and any other level FSK.

The LMX2572 gadget uses extremely little current and needs a single 3.3-V power source. Integrated LDOs provide internal power sources, disregarding the necessity for high-performance external LDOs. 1.8-V input is compatible with the digital logic interface. Through the serial interface, the user can program the gadget. The gadget can be turned off by modifying the registers or turning the Chip Enable (CE) pin.

Feature Description

Reference Oscillator Input

The gadget receives its frequency reference input from the OSCin pins. Due to the input’s high impedance, the pin needs AC-coupling capacitors. With a CMOS clock, XO, or single-ended differential clock, the OSCin pins can be driven single-ended. Additionally, the device supports differential clock input, making it simpler to interface with high-performance system clock components like TI’s LMK series clock components. When programming FCAL EN, a suitable reference signal must be applied at the OSCin pin because the OSCin signal serves as a clock for the VCO calibration.

PLL N Divider and Fractional Circuitry

The fractional compensation feature of the N divider allows it to achieve any fractional denominator (PLL DEN) between 1 and (232 – 1). The entire value of the N divider is represented by the integer component of N (PLL N), and the remaining fraction is represented by Nfrac = PLL NUM / PLL DEN. PLL N, PLL NUM, and PLL DEN can all be programmed using the software. The resolution step of the output is finer the greater the denominator. For instance, the output can increase in increments of 200 MHz / (232 – 1) = 0.0466 Hz even when FPD = 200 MHz.

Voltage-Controlled Oscillator

A fully integrated VCO is part of the LMX2572. With the help of the tuning voltage from the loop filter, the VCO produces a frequency that changes. The entire 3.2 to 6.4 GHz VCO frequency range spans an octave, enabling the channel divider to handle frequencies below the lower bound.

The VCO frequency range is split into 6 distinct frequency bands to lower the VCO’s tuning gain and improve the VCO’s phase noise performance. As a result, frequency calibration is required to establish the proper frequency band supplied in the intended output frequency. Additionally, the VCO is the amplitude adjusted to reduce phase noise. Certain calibration routines become active when the FCAL EN bit is set to one in the R0 register. Before starting the VCO calibration, a reliable OSCin signal must be present.

Without re-calibrating the VCO, this device can support a full sweep of the valid temperature range of 125°C (-40°C to 85°C). This is necessary for the synthesizer to operate continuously, even when temperatures vary greatly.

Voltage-Controlled Oscillator

There is a wholly integrated VCO in the LMX2572. The tuning voltage from the loop filter affects the frequency that the VCO generates. The channel divider can handle frequencies below the lower bound since the full VCO frequency range, 3.2 to 6.4 GHz, covers an octave. The VCO frequency range is split into 6 distinct frequency bands to lower the VCO’s tuning gain and improve the VCO’s phase noise performance.

As a result, frequency calibration is required to establish the proper frequency band supplied in the intended output frequency. Additionally, the VCO is the amplitude adjusted to reduce phase noise. Certain calibration routines become active when the FCAL EN bit is set to one in the R0 register. Before starting the VCO calibration, a reliable OSCin signal must be present. Without re-calibrating the VCO, this device can support a full sweep of the valid temperature range of 125°C (-40°C to 85°C). This is crucial for the synthesizer to run continuously, even in extreme temperature variations.

Conclusion

A 100-nF capacitor ought to be put close to each power supply pin, according to TI. Use a ferrite bead on each power supply pin to slightly minimize spurs if fractional spurs are a significant concern. LDOs built into this gadget increase its resilience to power supply noise.

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