Amplifier Circuit DiagramsRadio RF Wifi Circuit Diagrams

Single-Chip VHF RF Preamp Schematic Circuit Diagram

High-Performance RF Amplifier for VHF Bands

This RF amplifier is engineered to deliver exceptional performance across the entire VHF broadcast and PMR band (100-175 MHz) without the need for specialized testing equipment. Utilizing a grounded-gate configuration, the amplifier achieves inherent stability, eliminating the requirement for neutralization when appropriate PCB layout techniques are implemented. The amplifier’s performance stands out with a noise figure below 2 dB and a gain exceeding 13 dB. These impressive specifications enable car radios and home stereo receivers to capture lower-power local or campus radio stations, as well as distant amateur VHF stations in the 2-meters band. Notably, FM receivers suffer abrupt signal losses, leading to fading in and out of radio stations during drives. This amplifier can significantly enhance reception, providing a drastic improvement in such scenarios.

Single-Chip VHF RF Preamp Schematic Circuit Diagram

The Versatile MAX2633 Low-Voltage, Low-Noise Amplifier

The MAX2633 stands as a versatile low-voltage. Low-noise amplifier suitable for VHF to SHF frequencies. Operating efficiently with a single +2.7 V to +5.5 V supply, this amplifier exhibits virtually flat gain responses up to 900 MHz. With its low noise figure and modest supply current requirements, it proves to be an excellent choice for various RF applications, including reception, buffering, and transmission. The MAX2633 incorporates internal biasing, allowing for user-selectable supply current adjustments through the addition of a single external resistor, exemplified here by R1.

The circuit’s power draw remains at a mere 3 mA. Beyond a single bias resistor, the MAX2630 family of RF amplifiers necessitates only a handful of external components, specifically input and output blocking capacitors (C1 and C3), and a VCC bypass capacitor (C2). For these coupling capacitors, their size must be substantial enough to introduce negligible reactance within a 50-Ω system operating at the lowest frequency. To calculate their minimum value, the equation Cc = 53000/flow [pdf] is employed.

MAX2630 Series: Low-Voltage, Low-Noise Amplifiers for VHF to Microwave Frequencies

The MAX2630, MAX2631, MAX2632, and MAX2633 form part of the MAX2630 series. A family of low-voltage, low-noise amplifiers built to handle VHF to microwave frequencies. These versatile devices operate efficiently from a single +2.7V to +5.5V supply, offering a consistently flat gain response up to 900MHz. Their impressively low noise figures and modest supply current requirements make them exceptionally well-suited for a variety of applications, including reception, buffering, and transmitting IF signals.


  • Single +2.7V to +5.5V Operation
  • Internally Biased (MAX2630/MAX2631)
  • Adjustable Bias (MAX2632/MAX2633)
  • 6.6mA Supply Current (insensitive to the supply voltage)
  • 1µA Shutdown Current (MAX2631/MAX2633)
  • 3.7dB Noise Figure
  • 13.4dB Gain
  • Ultra-Small SOT Packages

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