100 MH TO 4000 MH RF/IF Digitally Controlled VGA

The ADL5243 is a high performance, digitally controlled variable gain amplifier operating from 100 MHz to 4000 MHz.

The VGA integrates two high performance amplifiers and a digital step attenuator (DSA). Amplifier 1 (AMP1) is an internally matched gain block amplifier with 20 dB gain, and Amplifier 2 (AMP2) is a broadband ¼ W driver amplifier that requires very few external tuning components. The DSA is 6-bit with a 31.5 dB gain control range, 0.5 dB steps, and ±0.25 dB step accuracy. The attenuation of the DSA can be controlled using a serial or parallel interface.

The gain block and DSA are internally matched to 50 Ω at their inputs and outputs, and all three internal devices are separately biased. The separate bias allows all or part of the ADL5243 to be used, which allows for easy reuse throughout a design. The pinout of the ADL5243 also enables the gain block, DSA, or ¼ W driver amplifier to be first, giving the VGA maximum flexibility in a signal chain.

The ADL5243 consumes 175 mA and operates off a single supply ranging from 4.75 V to 5.25 V. The VGA is packaged in a thermally efficient, 5 mm × 5 mm, 32-lead LFCSP and is fully specified for operation from −40°C to +85°C. A fully populated evaluation board is available.

Applications

* Wireless infrastructure

* Automated test equipment

* RF/IF gain control

* Operating frequency from 100 MHz to 4000 MHz

* Digitally controlled VGA with serial and parallel interfaces

* 6-bit, 0.5 dB digital step attenuator

* 31.5 dB gain control range with ±0.25 dB step accuracy

* Gain block, DSA, or ¼ W driver amplifier can be first

* The companion ADL5240 integrates a gain block with DSA

* Gain Block Amplifier 1

Gain: 19.2 dB at 2140 MHz

OIP3: 40.2 dBm at 2140 MHz

P1dB: 19.8 dBm at 2140 MHz

Noise figure: 2.9 dB at 2140 MHz

* ¼ W Driver Amplifier 2

Gain: 14.2 dB at 2140 MHz

OIP3: 41.1 dBm at 2140 MHz

P1dB: 26.0 dBm at 2140 MHz

Noise figure: 3.7 dB at 2140 MHz

* Low quiescent current of 175 mA