10 MHz to 3 GHz VGA with 60 dB Gain Control Range

The ADL5330 is a high performance, voltage controlled, variable gain amplifier (VGA)/attenuator for use in applications with frequencies up to 3 GHz. The balanced structure of the signal path minimizes distortion while it also reduces the risk of spurious feedforward at low gains and high frequencies caused by parasitic coupling. While operation between a balanced source and load is recommended, a single sided input is internally converted to differential form.

The input impedance is 50 Ω from INHI to INLO. The outputs are usually coupled into a 50 Ω grounded load via a 1:1 balun. A single supply of 4.75 V to 5.25 V is required.

The 50 Ω input system converts the applied voltage to a pair of differential currents with high linearity and good common rejection even when driven by a single sided source. The signal currents are then applied to a proprietary voltage controlled attenuator providing precise definition of the overall gain under the control of the linear in dB interface. The GAIN pin accepts a voltage from 0 V at minimum gain to 1.4 V at full gain with a 20 mV/dB scaling factor.

The output of the high accuracy wideband attenuator is applied to a differential transimpedance output stage. The output stage sets the 50 Ω differential output impedances and drives the OPHI and OPLO pins. The ADL5330 has a power-down function. It can be powered down by a Logic LO input on the ENBL pin. The current consumption in power-down mode is 250 μA.

The ADL5330 is fabricated on an Analog Devices, Inc., proprietary high performance, complementary bipolar IC process. The ADL5330 is available in a 24-lead (4 mm × 4 mm), Pb-free LFCSP package and is specified for operation from ambient temperatures of −40°C to +85°C. An evaluation board is also available.

Applications

* Transmit and receive power control at RF and IF

* Voltage controlled amplifier/attenuator

* Operating frequency 10 MHz to 3 GHz

* Optimized for controlling output power

* High linearity: OIP3 31 dBm at 900 MHz

* Output noise floor: −150 dBm/Hz at 900 MHz

* 50 Ω input and output impedances

* Single-ended or differential operation

* Wide gain control range: −34 dB to +22 dB at 900 MHz

* Linear in dB gain control function, 20 mV/dB

* Single-supply 4.75 V to 5.25 V