FRACTIONAL-N RF/INTEGER-N IF DUAL PLL

S1M8831A/33

1

INTRODUCTION

The S1M8831A/33 is a Fractional-N frequency synthesizer with integrated

prescalers, designed for RF operation up to 1.2GHz/K-PCS and for IF

operation up to 520MHz. The fractional-N synthesizer allows fast-locking,

low phase noise phase-locked loops to be built easily, thus having rapid

channel switching and reducing standby time for extended battery life. The

S1M8831A/33 based on

∑ - ∆ fractional-N techniques solves the fractional

spur problems in other fractional-N synthesizers based on charge pump

compensation. The synthesizer also has an additional feature that the

PCS/CDMA channel frequency in steps of 10kHz can be accurately

programmed.

The S1M8831A/33 contains dual-modulus prescalers. The S1M8831A RF

synthesizer adopts an 8/9 prescaler (16/17 for the S1M8833) and the IF

synthesizer adopts an 8/9 prescaler. Phase detector gain is user-programmable for maximum flexibility to

address IS-95 CDMA and IMT2000. Various program-controlled power down options as well as low supply

voltage help the design of wireless cell phones having minimum power consumption.

Using the Samsung's proprietary digital phase-locked-loop technique, the S1M8831A/33 has a linear phase

detector characteristic and can be used for very stable, low noise PLLs. Supply voltage can range from 2.7V to

4.0V. The S1M8831A/33 is available in a 24-QFN package.

FEATURES

•

High operating frequency dual synthesizer

— S1M8831A: 0.71 to 1.2GHz(RF)/ 45 to 520MHz(IF)

— S1M8833: 1.6 to 1.65GHz(RF)/ 45 to 520MHz(IF)

•

Operating voltage range: 2.7 to 4.0V

•

Low current consumption (S1M8831A: 5.0mA, S1M8833: 7.0mA)

•

Selectable power saving mode (I

•

Dual-modulus prescaler and Fractional-N/Integer-N:

— S1M8831A

(RF) 8/9

Fractional-N

— S1M8833

(RF) 16/17

Fractional-N

— S1M8831A/33

(IF)

8/9

Integer-N

•

Excellent in-band phase noise ( – 85dBc/Hz @ PCS, -90dBc/Hz @CDMA)

Improved fractional spurious performance ( < 80dBc)

•

Frequency resolution (= 10kHz/64 @ fref = 9.84MHz)

•

Fast channel switching time: < 500us

•

Programmable charge pump output current: from 50uA to 800uA in 50uA steps

•

Programmability via on-chip serial bus interface

24-QFN-3.5

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