Philips Semiconductors

Objective specification

SA9024

900 MHz transmit modulator and 1.3 GHz

fractional–N synthesizer

1997 Aug 01

5

OPERATING MODES & POWER DOWN CONTROL

There are two power saving modes of operation which the SA9024

can be put into, dependent on the status of the system. The

intention of these different modes is to disable circuity that is not in

use at the time in order to reduce power consumption. During sleep

mode, only circuitry which is required to provide a master clock to

the digital portion of the system is enabled. During receive mode,

circuitry which is used to perform the receive function and provide a

master clock is enabled. In transmit mode all the functions of the

chip are enabled which are required to perform transmit, receive and

provide master clock.

SA9024 POWER MODE TRUTH TABLE

Sleep Mode

Receive Mode

Transmit Mode

Enabled

yes

no

yes

no

yes

no

Crystal Oscillator







Phase detector and charge pump (transmit offset)







VCO







SSB Up-converter







MCLK Buffer







RCLK Buffer







÷M offset loop divider



















I/Q Modulator







Variable Gain Amp.







Control Logic







Main Divider







Reference Divider







Auxiliary Divider







Main Phase Detector and charge pump







Auxiliary Phase Detector and charge pump







Lock Detect