LMX2531LQ1500E_08 Datasheet, PDF (1/24 Pages) National Semiconductor (TI) – High Performance Frequency Synthesizer System with Integrated VCO

September 4, 2008
LMX2531LQ1500E
High Performance Frequency Synthesizer System with
Integrated VCO
General Description
The LMX2531LQ1500E is a low power, high performance
frequency synthesizer system which includes a fully integrat-
ed delta-sigma PLL and VCO with fully integrated tank circuit.
The third and fourth poles are also integrated and also ad-
justable. Also included are integrated ultra-low noise and high
precision LDOs for the PLL and VCO which give higher supply
noise immunity and also more consistent performance. When
combined with a high quality reference oscillator, the
LMX2531LQ1500E generates very stable, low noise local os-
cillator signals for up and down conversion in wireless com-
munication devices. The LMX2531LQ1500E is a monolithic
integrated circuit, fabricated in an advanced BiCMOS pro-
cess. There are several different versions of this product in
order to accomdate different frequency bands.
Device programming is facilitated using a three-wire
MICROWIRE Interface that can operate down to 1.8 volts.
Supply voltage range is 2.8 to 3.2 Volts. The
LMX2531LQ1500E is available in a 36 pin 6x6x0.8 mm Lead-
Free Leadless Leadframe Package (LLP).
Features
■ ^{PLL Features}
— Fractional-N Delta Sigma Modulator Order
programmable up to 4th order
— FastLock/Cycle Slip Reduction with Timeout Counter
— Partially integrated, adjustable Loop Filter
— Very low phase noise and spurs
■ ^{VCO Features}
— Integrated tank inductor
— Low phase noise
— 1499 - 1510 MHz Output Frequency
— 749.5 - 755 MHz Output Frequency (Divide by 2 Mode)
■ ^{Other Features}
— 2.8 V to 3.2 V Operation
— Low Power-Down Current
— 1.8V MICROWIRE Support
— Package: 36 Lead LLP
Target Applications
■ ^{Data Converting Clocking}
Functional Block Diagram
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