/a>Amplifier” title=”Amplifier”>Amplifier” title=”Amplifier”>Amplifier (VGA), with dB linear gain control, operating frequency from low frequency to 1GHz, VGA and AGC working mode, continuous gain control range 48dB, maximum Noise at gain (NF) is 6.8dB, IMD3 at 1.0V output is greater than 62dBc, single power supply 5V operation, mainly used in point-to-multipoint radio, instrumentation and medical electronics. This article introduces the block diagram, VGA1 and VGA2 functional block diagram, Basic connection circuit diagram as well as evaluation board circuit diagram, bill of materials and component layout.
ADL5336 : Cascadable IF VGAs with Programmable RMS Detectors
The ADL5336 consists of a pair of variable gain amplifiers (VGAs) designed for cascaded IF applications. The amplifiers have linear-in-dB gain control and operate from low frequencies to 1 GHz. Their excellent gain conformance over the control range and flatness over frequency are due to Analog Devices, Inc., patented X-AMP® architecture, an innovative technique for implementing high performance variable gain control.
Each VGA has 24 dB of gain control range. Their maximum gain can be independently programmable over a 6 dB range via the SPI. The VGAs can be cascaded to provide a total range of 48 dB. When connected to a 50 Ω source through a 1 :4 balun, the gain is 6 dB higher. The second VGA has an SPI programmable input switch that selects one of two external inputs.
When driven from a 200 Ω source or from a 50 Ω source through a 1:4 balun, the noise figure (NF) for the composite amplifier is 6.8 dB at maximum gain. The output of each VGA can drive 100 Ω loads to 5 V pp maximum.
Each VGA has an independent square law detector for autonomous, automatic gain control (AGC) operation. Each detector setpoint can be programmed independently through the SPI from −24 dBV to −3 dBV in 3 dB steps. When both VGAs are arranged in AGC mode and are programmed to the same setpoint, the composite NF increases to 9 dB when backed off by 18 dB from maximum gain.
The ADL5336 operates from a 5 V supply and consumes a typical supply current of 80 mA. When disabled, it consumes 4 mA. It is fabricated in an advanced silicon-germanium BiCMOS process and is available in a 32-lead exposed paddle LFCSP package. Performance is specified over a −40°C to +85°C temperature range.
ADL5336 main features:
Pair of VGAs with rms AGC detectors
VGA and AGC modes of operation
Continuous gain control range: 48 dB
Noise figure (NF) = 6.8 dB at maximum gain
IMD3 > 62 dBc for 1.0 V pp composite output
Differential input and output
Multiplexed inputs for VGA2
Programmable detector AGC setpoints
Programmable VGA maximum gain
Single 5 V supply operation
Figure 1. ADL5336 block diagram
Figure 2. VGA1 functional block diagram
Figure 3. VGA2 functional block diagram
Figure 4. ADL5336 basic connection circuit diagram
Figure 5. ADL5336 Evaluation Board Circuit Diagram
Evaluation Board Bill of Materials (BOM):
Figure 6. ADL5336 Evaluation Board Component Layout
For details, see:
The Links: EL640.480-AD4 VUB72-16NO1