DTL-TTL Controlled Buffered Analog Switch

Description: This analog switch utilizes the 2N4860 JFET, which features a low on-resistance (rON) of 25 ohms and minimal leakage current. The LM102 acts as a voltage buffer in the circuit. It is designed to be adaptable for use in a dual trace oscilloscope chopper configuration. The DM7800 monolithic integrated circuit offers sufficient switch drive capabilities, controlled by DTL-TTL logic levels. A schematic drawing is provided.

The circuit employs the 2N4860 JFET as the primary switching element, taking advantage of its low on-resistance to minimize signal loss and enhance performance in applications requiring precise signal integrity. The low leakage characteristics of the JFET are critical for maintaining signal fidelity, especially in high-impedance circuits.

The LM102, functioning as a voltage buffer, provides isolation between the input control signal and the JFET switch. This configuration ensures that variations in load do not affect the control voltage, thereby stabilizing the operation of the switch. The LM102 is known for its high-speed performance, making it suitable for applications where rapid switching is necessary.

For the control logic, the DM7800 monolithic IC is employed. This integrated circuit is designed to interface with DTL (Diode-Transistor Logic) and TTL (Transistor-Transistor Logic) levels, allowing for compatibility with a variety of digital control systems. The DM7800 is capable of delivering the necessary drive current to the JFET, ensuring reliable switching action while maintaining the integrity of the control signal.

This circuit can be effectively adapted for use in a dual trace oscilloscope chopper configuration, allowing for the simultaneous observation of two different signals on a single display. The design facilitates the rapid alternation between the two channels, providing a clear and concise representation of the signals being analyzed. The schematic drawing included serves as a visual representation of the circuit layout, illustrating the interconnections between the components and aiding in the understanding of the circuit operation.This analog switch uses the 2N4860 JFET for its 25 ohm rON and low leakage. The LM102 serves as a voltage buffer. This circuit can be adapted to a dual trace oscilloscope chopper. The DM7800 monolithic IC provides adequate switch drive controlled DTL-TTL logic levels. Here is a schematic drawing: