ADI ADL5561 2GHz超低失真差分RF放大方案

ADI 公司的ADL5561是 2.0GHz超低失真差分RF/IF放大器.放大器的噪音为2.1 nV/√Hz,在很宽频率范围内有极好的失真性能.非常适合驱动8-16位高速ADC. ADL5561有三种增益选择:6db,12db 和15.5db.单端输入增益配置为5.6db, 11.1db 和14.1db.单电源2.8 V 到3.6 V工作,工作电流40mA,转换速率8V/ns.可用于差分ADC驱动器,单端到差分转换,RF/IF增益区块以及SAW滤波器接口等.本文介绍了ADL5561的主要特性,方框图以及用来测量失真和噪音的差分和单端输入评估板电路图.

ADL5561:2.0 GHz Ultralow Distortion Differential RF/IF Amplifier
The ADL5561 is a high performance differential amplifier optimized for RF and IF applications. The amplifier offers low noise of 2.1 nV/√Hz and excellent distortion performance over a wide frequency range making it an ideal driver for high speed 8-bit to 16-bit analog-to-digital converters (ADCs). The ADL5561 provides three gain levels of 6db, 12db and 15.5db through a pin strappable configuration. For the single ended input configuration the gains are reduced to 5.6db, 11.1db and 14.1db. Using an external series input resistor expands the amplifiers’ gain flexibility and allows for any gain selection form 0 to 15.5db. The quiescent current of the ADL5561 is typically 40 mA and when disabled consumes less than 3mA offering excellent input to output isolation. The device is optimized for wideband, low distortion perform- ance. These attributes, together with its adjustable gain capability, make this device the amplifier of choice for general- purpose IF and broadband applications where low distortion, noise, and power are critical. This device is optimized for the best combination of slew speed, BW and broadband distortion. These attributes allow it to drive a wide variety of A/D converters and is ideally suited for driving mixers, pin diode attenuators, SAW filters, and multielement discrete devices. Fabricated on an Analog Devices, Inc., high speed SiGe process, the ADL5561 is supplied in a compact 3 mm × 3 mm, 16-lead LFCSP package and operates over the temperature range of −40°C to +85°C.
ADL5561主要特性:
−3 dB bandwidth of 2.0 GHz (AV = 6 dB)
Pin strappable gain adjust: 6 dB, 12 dB, 15.5 dB
Low Supply Current 40mA
Differential or single-ended input to differential output
Low noise input stage: 2.1 nV/√Hz RTI @ AV = 12 dB
Low broadband distortion (Av = 6dB)
10 MHz: −94 dBc HD2, −91 dBc HD3
70 MHz: −90 dBc HD2, −90 dBc HD3
140 MHz: −82 dBc HD2, −87 dBc HD3
250 MHz: −78 dBc HD2, −80 dBc HD3
IMD3’s of 91dBc @ 250Mhz Center
Slew rate: 8 V/ns
Fast settling and overdrive recovery of 2 ns
Single-supply operation: 2.8 V to 3.6 V
Power down
Fabricated using the high speed XFCB3 SiGe process
ADL5561应用:
Differential ADC drivers
Single-ended to differential conversion
RF/IF gain blocks
SAW filter interfacing



图1.ADL5561功能方框图



图2.差分输入ADL5561评估板电路图(用来测量失真和噪音)



图3.单端输入ADL5561评估板电路图(用来测量失真和噪音)