National Manuals

The LMX2471 is a low power, high performance delta-sigma fractional-N PLL with an auxiliary integer-N PLL. The device is fabricated using National Semiconductor’s advanced BiC-MOS process. With delta-sigma architecture, fractional spur compensation is achieved with noise shaping capability of the delta-sigma modulator and the inherent low pass filtering of the PLL loop filter. Fractional spurs at lower frequencies are pushed to higher frequencies outside the loop bandwidth. Unlike analog compensation, the digital feedback techniques used in the LMX2471 are highly resistant to changes in temperature and variations in wafer processing. With delta-sigma architecture, the ability to push close in spur and phase noise energy to higher frequencies is a direct function of the modulator order. The higher the order, the more this energy can be spread to higher frequencies. The LMX2471 has a programmable modulator up to order four, which allows the designer to select the optimum modulator order to fit the phase noise, spur, and lock time requirements of the system. Programming is fast and simple. Serial data is transferred into the LMX2471 via a three line MICROWIRE interface (Data, Clock, Load Enable). Nominal supply voltage is 2.5 V. The LMX2471 features a typical current consumption of 5.6 mA at 2.5 V. The LMX2471 is available in a 24 lead 3.5 X 4.5 X 0.6 mm package. Features n Low power, high performance delta-sigma fractional-N PLLn Auxiliary integer-N PLLn Fabricated using National Semiconductor’s advanced BiC-MOS processn Noise shaping capability of the delta-sigma modulatorn Inherent low pass filtering of the PLL loop filtern Energy can be spread to higher frequenciesn Fast and simple programming

The LMX2470 is a low power, high performance delta-sigma fractional-N PLL with an auxiliary integer-N PLL. It is fabricated using National Semiconductor’s advanced BiCMOS process. The delta-sigma architecture allows for fractional spur compensation by utilizing the noise shaping capability of the delta-sigma modulator and the low pass filtering of the PLL loop filter. This pushes fractional spurs at lower frequencies to higher frequencies outside the loop bandwidth. The digital feedback techniques used in the LMX2470 are resistant to changes in temperature and variations in wafer processing, unlike analog compensation. The ability to push close in spur and phase noise energy to higher frequencies is directly related to the modulator order, with higher orders allowing for more energy spread to higher frequencies. The LMX2470 has a programmable modulator with a maximum order of four, allowing the designer to select the optimal modulator order for the system's phase noise, spur, and lock time requirements. Programming is simple and fast using a three line MICROWIRE interface. The LMX2470 operates at a nominal supply voltage of 2.5V and has a typical current consumption of 4.1mA. It is available in a 24 lead 3.5 X 4.5 X 0.6 mm package.

The LP2978 is a 50 mA, fixed-output voltage regulator designed to provide ultra low-dropout and low noise in battery powered applications. Using an optimized VIP™ (Vertically Integrated PNP) process, the LP2978 delivers unparalleled performance in all specifications critical to battery-powered designs: Dropout Voltage: Typically 120 mV @ 50 mA load, and 7 mV @ 1 mA load. Ground Pin Current: Typically 350 µA @ 50 mA load, and 75 µA @ 1 mA load. Enhanced Stability: The LP2978 is stable with output capacitor ESR as low as 5 mΩ, which allows the use of ceramic capacitors on the output. Sleep Mode: Less than 1 µA quiescent current when ON/OFF pin is pulled low. Smallest Possible Size: SOT-23 package uses absolute minimum board space. Precision Output: 1% tolerance output voltages available (A grade). Low Noise: By adding a 10 nF bypass capacitor, output noise can be reduced to 30 µV (typical).

LMX2430/LMX2433/LMX2434 PLLatinum™ Dual High Frequency Synthesizer for RF Personal Communications

LMX2377U is a ultra-low power dual frequency synthesizer from Linear Technology. It adopts a proprietary digital phase lock technique and can generate very stable, low noise control signals for UHF and VHF voltage controlled oscillators. The device features synchronous or asynchronous powerdown mode, and typically consumes 3.5 mA at 3.0V. LMX2377U is available in 20-Pin TSSOP, 24-Pin CSP and 20-Pin UTCSP packages.

The LMX237X family of monolithic, integrated dual frequency synthesizers, including prescalers, is designed to be used as a first and second local oscillator for dual mode or dual conversion transceivers.

The LMX2364 is a high-performance PLLatinum fractional frequency synthesizer that integrates a 2.6 GHz fractional frequency synthesizer and an 850 MHz low power integer-N frequency synthesizer. It is designed for use in the local oscillator subsystem of a radio transceiver, providing stable and low noise control signals for UHF and VHF voltage controlled oscillators.

The LMX2354 is a radio frequency frequency synthesizer manufactured by National Semiconductor. It is fabricated using National’s 0.5 μ ABiC V silicon BiCMOS process and consumes only 7.0 mA of power. The operating frequency range is 2.5 GHz to 550 MHz. The product uses quadruple modulus prescalers and modulo 15 or 16 fractional compensation circuitry in the RF divider to provide a continuous divide ratio of 80 to 32767 in 16/17/20/21 (1.2 GHz–2.5 GHz) fractional mode and 40 to 16383 in 8/9/12/13 (550 MHz–1.2 GHz) fractional mode.

The LMX2353 is a fractional N frequency synthesizer with 2.5 GHz frequency range, 2.7V - 5.5V operating voltage and 4.5 mA typical current consumption. It supports 16 levels programmable charge pump current.

LMX2350/LMX2352 is a low power frequency synthesizer produced by National Company, with a working frequency range of 2.5GHz/550MHz and 1.2GHz/550MHz. It is manufactured using National's 0.5µ ABiC V sili- con BiCMOS process, and has the characteristics of low power consumption and high stability

The LMX2346/LMX2347 are frequency synthesizers produced by National Semiconductor Corporation. Their working frequencies are 2.0GHz and 2.5GHz, and they support 2.7V to 5.5V voltage. They are manufactured using National's 0.5µ ABiC V silicon BiCMOS process and are available in 16-pin TSSOP and 16-pin CSP packages.

The LMX2335U/LMX2336U PLLatinum™ is an ultra low power dual frequency synthesizer for RF personal communications. LMX2335U is 1.2 GHz/1.2 GHz, LMX2336U is 2.0 GHz/1.2 GHz. These two devices are high performance frequency synthesizers with integrated dual modulus prescalers. The LMX2335U/LMX2336U devices are designed for use in applications requiring two RF phase-locked loops. A 64/65 or a 128/129 prescale ratio can be selected for each RF synthesizer. Using a proprietary digital phase locked loop technique, the LMX2335U/LMX2336U devices generate very stable, low noise control signals for the RF voltage controlled oscillators. Both RF synthesizers include two-level programmable charge pump. The RF1 synthesizera has dedicated Fastlock circuitry. Serial data is transferred to the devices via a three wire interface (Data, LE, Clock). Supply voltages from 2.7V to 5.5V are supported. The LMX2335U and the LMX2336U feature very low current consumption: LMX2335U (1.2 GHz)– 3.0 mA, LMX2336U (2.0 GHz)– 3.5 mA at 3.0V. The LMX2335U device is available in 16-pin TSSOP, and 16-pin Chip Scale Package (CSP) surface mount plastic packages. The LMX2336U device is available in 20-Pin TSSOP, 24-Pin CSP, and 20-Pin UTCSP surface mount plastic packages.

LMX2330L/LMX2331L/LMX2332L are a series of low power dual frequency synthesizers, suitable for RF personal communications. LMX2330L's RF frequency is 2.5 GHz, IF frequency is 510 MHz; LMX2331L's RF frequency is 2.0 GHz, IF frequency is 510 MHz; LMX2332L's RF frequency is 1.2 GHz, IF frequency is 510 MHz. The series of synthesizers use digital phase locked loop technology, combined with a high quality reference oscillator, provide the tuning voltages for voltage controlled oscillators to generate stable, low noise signals for RF and IF local oscillators. Serial data is transferred into the LMX233XL via a three wire interface (Data, Enable, Clock). Supply voltage ranges from 2.7V to 5.5V. The series of synthesizers has very low power consumption; LMX2330L - 5.0 mA at 3V; LMX2331L - 4.0 mA at 3V; LMX2332L - 3.0 mA at 3V. LMX233XL offers TSSOP 20-pin and CSP 24-pin surface mount plastic packages.

LMX2330A/LMX2331A/LMX2332A PLLatinum™ Dual Frequency Synthesizer for RF Personal Communications

LMX2323 is a 2.0GHz frequency synthesizer that uses a digital phase locked loop to generate stable, low-noise control signals