Using a proprietary digital-phase, locked-loop technique, the LMX243x devices generate very stable, low-noise control signals for RF and IF voltage controlled oscillators. Both the RF and IF synthesizers include a two-level programmable charge pump. Both the RF and IF PLLs have dedicated fastlock circuitry with integrated time-out counters which require only a single word write to power up or change frequencies. The LMX243x devices are high-performance frequency synthesizers with integrated dual-modulus prescalers. A 32/33 or a 16/17 prescale ratio can be selected for the 5-GHz LMX2434 RF synthesizer. An 8/9 or a 16/17 prescale ratio can be selected for both the LMX2430 and LMX2433 RF synthesizers. The IF circuitry contains an 8/9 or a 16/17 prescaler. Serial data is transferred to the devices through a three-wire interface (DATA, LE, CLK). A low voltage logic interface allows direct connection to 1.8-V devices. Supply voltages from 2.25 V to 2.75 V are supported.