SA9025 datasheet(20/23 Pages) PHILIPS

No de pièce	SA9025

Description	900 MHz transmit modulator and 2.2 GHz fractional-N synthesizer

Download	23 Pages

Scroll/Zoom	100%

Fabricant	PHILIPS [NXP Semiconductors]

Site Internet	http://www.nxp.com

Logo

20 / 23 page

Philips Semiconductors

Objective specification

SA9025

900 MHz transmit modulator and 2.2 GHz

fractional–N synthesizer

1997 Aug 01

20

SR01454

REFERENCE R

MAIN M

VCO CYCLES

N

N+1

N

N+1

DETECTOR

OUTPUT

ACCUMULATOR

24

1

3

0

FRACTIONAL

COMPENSATION

CURRENT

OUTPUT ON

PHP, PHI

PULSE

WIDTH

MODULATION

PULSE LEVEL

MODULATION

mA

µA

CONTENTS

Figure 10.

Waveforms for NF = 2; Fraction = 0.4

Figure 10 shows that for a proper fractional compensation, the area

of the fractional compensation current pulse must be equal to the

area of the charge pump ripple output.

The fractional compensation current is derived from the main charge

pump in that it will follow all the current scaling through external

resistor setting, programming or speedup operation.

For a given pump,

|comp

+

|pump

128

x

Fdac

5 x 128

xFRD

Where:

Icomp is the compensation current, Ipump is the pump current, Fdac

is the fractional DAC value and FRD is the fractional accumulator

value.

The theoretical value for Fdac would then be: 128 for Fmod = 1

(modulo 5) and 80 for Fmod = 0 (modulo 8).

When the serial input A word is loaded, the output circuits are in the

“speedup mode” as long as the STROBE is H, otherwise the

“normal mode” is active.

Lock Detect

The output LOCK maintains a logic ‘1’ when the auxiliary phase

detector ANDed with the main phase detector indicates a lock

condition. The lock condition for the main and auxiliary synthesizers

is defined as a phase difference of less than

"1 cycle on the

reference inputs XTAL1,2. The LOCK condition is also fulfilled when

the relative counter is disabled (PDmain = ‘0’ or PDaux = ‘0’) for the

main or auxiliary counter, respectively. Lock indication when PDmain

= PDaux = ‘0’.

Functional Description of Offset Loop, Modulator

and Power Control

Transmit Offset Synthesizer

The transmit offset phase locked loop portion of the SA9025 design

consists of the following functional blocks: reference oscillator,

limiters, phase detector,

÷M, IF VCO and passive loop filter.

Harmonic contents of this signal are attenuated by an LP filter. The

output of the IF VCO is also divided by N and compared with the

reference oscillator in the phase detector.

Reference Oscillator

This Oscillator is used to generate the reference frequency together

with an external crystal and varicap. The output is internally routed

to three buffers and a phase comparator. It is possible to run the

oscillator as an amplifier from an external reference signal (TCXO).

Phase Detector and Charge Pump

The phase comparator is used to compare the output of the divider

with the reference. It provides an output proportional to the phase

difference between the divided down VCO and the reference. This

output is then filtered and used as the control voltage input to the

VCO. The phase detector is a Gilbert multiplier cell type, having a

linear output from 0 to

π (π/2 ±π/2), followed by a charge pump. The

charge pump peak output current is programmable to 6.4mA via the

use of an external resistor.

A preliminary design analysis has been performed with the following

loop parameters:

A lock detect signal is provided and ANDed together with lock detect

signals from both the main channel synthesizer and auxiliary

Numéro de pièce similaire - SA9025

Fabricant	No de pièce	Fiches technique	Description
NXP Semiconductors	SA9024	151Kb / 23P	900 MHz transmit modulator and 1.3 GHz fractional-N synthesizer 1997 Aug 01

More results

Description similaire - SA9025

Fabricant	No de pièce	Fiches technique	Description
NXP Semiconductors	SA9024	151Kb / 23P	900 MHz transmit modulator and 1.3 GHz fractional-N synthesizer 1997 Aug 01
RF Micro Devices	RF6001	1Mb / 70P	FRACTIONAL-N RF SYNTHESIZER WITH MODULATOR AND DIGITAL IF FILTER
RF Micro Devices	RF6001	35Kb / 2P	FRACTIONAL-N RF SYNTHESIZER WITH MODULATOR AND DIGITAL IF FILTER
Skyworks Solutions Inc.	SKY74038	128Kb / 12P	2.6 GHz/800 MHz Dual Fractional-N/lnteger-N Frequency Synthesizer
Analog Devices	ADF4156	421Kb / 24P	6 GHz Fractional-N Frequency Synthesizer REV. 0
Analog Devices	ADF4156	393Kb / 24P	6.2 GHz Fractional-N Frequency Synthesizer Rev. E
Skyworks Solutions Inc.	CX74038	127Kb / 12P	2.6 GHz/800 MHz Dual Fractional-N/lnteger-N Frequency Synthesizer
Texas Instruments	TRF8010	185Kb / 10P	[Old version datasheet] 900-MHz RF TRANSMIT DRIVER
Texas Instruments	TRF8010_1998	188Kb / 10P	[Old version datasheet] 900-MHz RF TRANSMIT DRIVER
Hittite Microwave Corpo...	HMC703LP4E	3Mb / 52P	8 GHZ FRACTIONAL SYNTHESIZER

More results

SA9025 Fiches technique(PDF) 20 Page - NXP Semiconductors

SA9025 Fiches technique(HTML) 20 Page - NXP Semiconductors

Numéro de pièce similaire - SA9025

Description similaire - SA9025

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Fiches technique Télécharger

Lien URL