B4M1: DIP8 ±20 dB Adjustable Inverting Audio Amplifier

This is a potentiometer adjustable inverting gain stage in a DIP8 footprint for convenient breadboard prototyping. The whole module only occupies the space of a through hole dual op-amp.

Price: £11 (PCB with SMT components installed, through hole components included), £20 (+ through hole components installed)

If you have any questions please feel free to contact me via enquiries@macalisterelectronics.com or via Twitter (@macco_electro).

Gallery~

Detailed Description~

The goal for this module was to implement an adjustable gain/attenuation stage that could be adjusted without a screwdriver, in the smallest possible footprint. This module implements an inverting amplifier with gain adjustable from -20 to +20 dB. The actual circuit is shown below.

The module fits inside a DIP8 footprint whilst still including a potentiometer with an integrated knob. Typically implementing this functionality on a breadboard with discrete components would involve using a DIP8 op-amp and a through-hole potentiometer next to it (plus some TH passives). With this module it can implemented within the same footprint as just the op-amp.

Details of the dimensions are shown below.

Pinout~

Specification~

• Dimensions
  • Width : 10.16 mm
  • Depth : 10.16 mm
  • Total Height : 22.3 mm
  • Height Above PCB : 17.8 mm
• Weight : 2 g
• Gain range : ± 20 dB
• Bandwidth : 19 kHz
• Port impedances
  • Input : 1 kΩ
  • Output : <1 Ω
• Input signal range
  • Upper limit: V₊ + 0.1 V
  • Lower limit: V_- - 0.1 V
• Power supply
  • Required supplies : V₊, V_ref, V_-
  • Reference voltage (V_ref) : nominally (V₊ - V_-)/2, should match the 0 V reference of the input and output signals
  • Voltage range (V₊ - V_-) : 2.7 to 16 V
  • Quiescent current : <0.8 mA