Analog Devices Inc./Maxim Integrated

The LT5516 is an 800MHz to 1.5GHz direct conversion quadrature demodulator optimized for high linearity receiver applications. It is suitable for communications receivers where an RF or IF signal is directly converted into I and Q baseband signals with bandwidth up to 260MHz. The LT5516 incorporates balanced I and Q mixers, LO buffer amplifiers and a precision, high frequency quadrature generator.In an RF receiver, the high linearity of the LT5516 provides excellent spur-free dynamic range, even with fixed gain front end amplification. This direct conversion receiver can eliminate the need for intermediate frequency (IF) signal processing, as well as the corresponding requirements for image filtering and IF filtering. Channel filtering can be performed directly at the outputs of the I and Q channels. These outputs can interface directly to channelselect filters (LPFs) or to a baseband amplifier.ApplicationsCellular/PCS/UMTS InfrastructureHigh Linearity Direct Conversion I/Q ReceiverHigh Linearity I/Q Demodulator

The LT5517 is a 40MHz to 900MHz quadrature demodulator optimized for high linearity receiver applications where high dynamic range is important. It is suitable for communications receivers where an RF or IF signal is directly converted into I and Q baseband signals with a bandwidth up to 130MHz. The LT5517 incorporates balanced I and Q mixers, LO buffer amplifiers and a precision, broadband quadrature generator derived from an on-chip divide-by-two circuit.The superior linearity and low noise performance of the LT5517 is achieved across its full frequency range. A well-balanced divide-by-two circuit generates precision quadrature LO carriers to drive the I mixer and the Q mixer. Consequently, the outputs of the I-channel and the Q-channel are well matched in amplitude, and their phases are 90° apart. The LT5517 also provides excellent 50Ω impedance matching at the 2XLO port across its entire frequency range.ApplicationsWireless InfrastructureHigh Linearity Direct Conversion I/Q ReceiverHigh Linearity I/Q Demodulator

The LT5518 is a direct I/Q modulator designed for high performance wireless applications, including wireless infrastructure. It allows direct modulation of an RF signal using differential baseband I and Q signals. It supports PHS, GSM, EDGE, TD-SCDMA, CDMA, CDMA2000, W-CDMA and other systems. It may also be configured as an image reject up-converting mixer, by applying 90° phase-shifted signals to the I and Q inputs. The high impedance I/Q baseband inputs consist of voltage-to-current converters that in turn drive double-balanced mixers. The outputs of these mixers are summed and applied to an on-chip RF transformer, which converts the differential mixer signals to a 50Ω single-ended output. The balanced I and Q baseband input ports are intended for DC coupling from a source with a common mode voltage level of about 2.1V. The LO path consists of an LO buffer with single-ended input, and precision quadrature generators that produce the LO drive for the mixers. The supply voltage range is 4.5V to 5.25V.ApplicationsInfrastructure Tx for DCS, PCS and UMTS BandsImage Reject Up-Converters for DCS, PCS and UMTS BandsLow Noise Variable Phase-Shifter for 1.5GHz to 2.4GHz Local Oscillator Signals

The LT5524 is a programmable gain amplifier (PGA) with bandwidth extending from low frequency (LF) to 540MHz. It consists of a digitally controlled variable attenuator, followed by a high linearity amplifier. Four parallel digital inputs control the gain over a 22.5dB range with 1.5dB step resolution. An on-chip power supply regulator/filter helps isolate the amplifier signal path from external noise sources.The LT5524’s open-loop architecture offers stable operation for any practical load conditions, including peaking-free AC response when driving capacitive loads, and excellent reverse isolation.The LT5524 may be operated broadband, where the output differential RC time constant sets the bandwidth, or it may be used as a narrowband driver with the appropriate output filter.ApplicationsHigh Linearity ADC DriverIF Sampling ReceiversVGA IF Power Amplifier50Ω DriverInstrumentation Applications

The LT5525 is a low power broadband mixer optimized for high linearity applications such as point-to-point data transmission, high performance radios and wireless infrastructure systems. The device includes an internally 50Ω matched high speed LO amplifier driving a double-balanced active mixer core. An integrated RF buffer amplifier provides excellent LO-RF isolation. The RF input balun and all associated 50Ω matching components are integrated. The IF ports can be easily matched across a broad range of frequencies for use in a wide variety of applications.The LT5525 offers a high performance alternative to passive mixers. Unlike passive mixers, which require high LO drive levels, the LT5525 operates at significantly lower LO input levels and is much less sensitive to LO power level variations.*Operation over a wider frequency range is achievable with reduced performance. Consult factory for more information.ApplicationsPoint-to-Point Data Communication SystemsWireless InfrastructureHigh Performance RadiosHigh Linearity Receiver Applications