United States Patent 3,538,449
November 3, 1970
Lateral PNP-NPN Composite Monolithic Differential Amplifier
James E. Solomon
Filed November 22, 1968
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 descriptions: cover graphic
- 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
- 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
- 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.
3,177,414 04/1965 Kurosawa et al.
3,373,369 03/1968 Cones