Abstract of the Disclosure

Disclosed is a differential amplifier adapted for monolithic integrated circuit fabrication which includes a pair of input NPN transistors connected to a pair of output lateral PNP transistors. The lateral PNP transistors clamp the collector voltage of the input NPN transistors so that the input NPN transistors may be fabricated to have a high current gain and thus require very low input currents. At the same time, the output currents from the output lateral PNP transistors are made independent of PNP common-emitter current gain (beta), and the frequency response of the complete amplifier is improved over other prior art approaches

• Figure 1 is a schematic diagram of the NPN-lateral PNP monolithic circuit configuration for one-half of the differential amplifier according to one embodiment of the invention.
• Figure 2 is a schematic diagram of one differential amplifier embodying the present invention and having apair of current sources and a single current sink.
• Figure 3 is a schematic diagram of another embodiment of the invention and includes a single current source and a pair of current sinks.
• Figure 4 is a schematic diagram of another embodiment of the invention and is somewhat dimilar to Figure 2. figure 4 includes emitter-resistors between the amplifier transistors and the single current sink of the amplifier circuit.
• Figure 5 is a schematic diagram of another embodiment of the invention. Figure 5 is somewhat similar to Figure 3 and includes a pair of resistors connected between the single current source and the source current nodes for the amplifier transistors.
• Figure 6 is a schematic diagram of another embodiment of the invention and includes still further emitter resistors for the output lateral PNP transistors of the amplifier circuit.

 Citations [54]:
  
3,177,414  04/1965  Kurosawa et al.
3,373,369  03/1968  Cones