Analog Devices, Inc. (Analog Devices) has introduced two new ultra-low-distortion differential amplifiers, ADL5561 and ADL5562 that address new performance standards for linearity and power consumption. The new differential amplifiers efficiently drive high-speed, high-IF sampling analog-to-digital converters (ADCs) for advanced communications systems. The 2-GHz ADL5561 ultra-low-distortion differential amplifier consumes 40 mA.

The ADL5561 and ADL5562 are capable of maintaining performance while driving ADCs up to 500 MHz, exceeding the current maximum of 380 MHz, set in 2005 by ADI’s AD8352 differential amplifier.

On-chip, user-selectable gain-setting resistors enable ADI to provide detailed specifications at common IF frequencies (70 MHz, 100 MHz, 140 MHz, and 250 MHz) and common gain settings (6 dB, 12 dB, 15.5 dB). This degree of specified performance simplifies and expedites the design process, provides previously unattainable flexibility, and allows the designer to exploit fully the amplifier’s performance at multiple gain settings and IF frequencies. Additionally, the pin-compatible ADL5561 and ADL5562 allow the user to select power consumption and performance to meet the requirements for a given application.

The ADL5561 and ADL5562 amplifiers drive 12- to 16-bit ADCs at the highest practical IF frequencies for use in next-generation communications systems, such as 3G LTE (Long-Term Evolution) and NGMN (Next Generation Mobile Networks). In current demanding advanced-radio applications, lowering the distortion level of the ADC driver improves system performance at higher frequencies by helping to maximize the receive channel’s SFDR (spurious free dynamic range) and minimize its SNR (signal-to-noise-ratio). This improvement minimizes the number of IF frequencies within the radio design, resulting in lower power, cost, component count, and board area, and advancing system-level performance in applications such as wireless base stations, cable communications, medical and instrumentation, military and satellite communications.

ADL5561 and ADL5562 set new standards with exceptional performance and low power within small footprint package

The 2-GHz ADL5561 ultra-low-distortion differential amplifier consumes just 40 mA and makes it suitable for use in sub-140 MHz IF applications. The ADL5561 beats the industry’s best performance and provides new a benchmark for performance vs. power consumption with maximum flexibility. The ADL5561 achieves distortion levels of –86 dBc HD2, –88 dBc HD3, and –95 dBc IMD3 at 100 MHz.

The 2.6 GHz ADL5562 ultra-low-distortion differential amplifier consumes 80 mA, setting a new standard for the industry’s lowest distortion for IF applications up to 500 MHz. The ADL5562 achieves distortion levels of –95 dBc HD2, –86 dBc HD3, and –96 dBc IMD3 at 140 MHz.

Both the ADL5561 and ADL5562 operate on a 3-volt power supply and are available in a space-saving 3 mm × 3 mm LFCSP. Furthermore, unlike conventional GaAs differential amplifiers, which often require the use of a transformer to perform the single-ended to differential conversion, the ADL5561 and ADL5562 can operate in fully differential circuits or provide the single-ended to differential conversion.