LMX2522/LMX2532

Integrated VCOs

General Description

LMX2522 and LMX2532 are highly integrated, high perfor-

mance, low power frequency synthesizer systems optimized

for Korean PCS (K-PCS) with GPS and Korean Cellular

(K-Cellular) with GPS, CDMA (1xRTT, IS-95) mobile hand-

sets. Using a proprietary digital phase locked loop tech-

nique, LMX2522 and LMX2532 generate very stable, low

noise local oscillator signals for up and down conversion in

wireless communications devices.

LMX2522 and LMX2532 include a RF voltage controlled

oscillator (VCO), a GPS VCO, a loop filter, and a fractional-N

RF PLL based on a delta sigma modulator. In concert these

blocks form a closed loop RF and GPS synthesizer system.

LMX2522 supports the Korean PCS band with GPS and

LMX2532 supports the Korean Cellular band with GPS.

LMX2522 and LMX2532 include an Integer-N IF PLL also.

For more flexible loop filter designs, the IF PLL includes a

4-level programmable charge pump. Together with an exter-

nal VCO and loop filter, LMX2522 and LMX2532 make a

complete closed loop IF synthesizer system.

Serial data is transferred to the device via a three-wire

MICROWIRE interface (DATA, LE, CLK).

Operating supply voltage ranges from 2.7 V to 3.3 V.

LMX2502 and LMX2512 feature low current consumption:

17 mA at 2.8 V.

LMX2522 and LMX2532 are available in a 28-pin leadless

leadframe package (LLP).

Features

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Small Size

Small 5.0 mm x 5.0 mm x 0.75 mm 28-Pin LLP Package

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RF/GPS Synthesizer System

Integrated RF VCO

Integrated GPS VCO

Integrated Loop Filter

Low Spurious, Low Phase Noise Fractional-N RF PLL

Based on 11-bit Delta Sigma Modulator

10 kHz Frequency Resolution

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IF Synthesizer System

Integer-N IF PLL

Programmable Charge Pump Current Levels

Programmable Frequencies

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Supports Various Reference Oscillator Frequencies

19.20/19.68 MHz

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Fast Lock Time: 500 µs

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Low Current Consumption

17 mA at 2.8 V

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2.7 V to 3.3 V Operation

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Digital Filtered Lock Detect Output

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Hardware and Software Power Down Control

Applications

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Korean PCS CDMA Systems with GPS

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Korean Cellular CDMA Systems with GPS

Functional Block Diagram

20067201

PLLatinum is a trademark of National Semiconductor Corporation.

June 2003

© 2003 National Semiconductor Corporation

DS200672

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