Title:
CIRCUIT AND METHOD FOR REDUCING NONLINEARITY IN ANALOG OUTPUT CURRENT BY WASTE CURRENT CONVERSION
Document Type and Number:
Japanese Patent JPS59131223
Kind Code:
A
Abstract:
An integrated circuit digital to analog converter includes circuitry having first and second resistors in a R/2R resistor ladder which scales bit current contributions to an analog output current. Each of the first and second resistors have a respective terminal connected to the collector of a bit current transistor, the emitter of which is connected to the emitter of a waste current transistor. The digital to analog converter includes a metal ground voltage conductor having a "shared node" and a distributed resistance between one side of the shared node and a main ground voltage connection. The collector of the waste current transistor and a second terminal of the first resistor are both connected directly to the shared node. In operation, the waste current transistor switches waste current into the shared node, rather than into a separate waste current ground conductor. This results in substantially less voltage variation across the distributed resistance of the metal ground voltage conductor, and consequently lower non-linearity, than is the case if waste current is switched into the separate ground conductor.
Inventors:
ANSONII DEII UON
DONARUDO RII BURAMUBOO
DONARUDO RII BURAMUBOO
Application Number:
JP16493483A
Publication Date:
July 28, 1984
Filing Date:
September 07, 1983
Export Citation:
Assignee:
BURR BROWN RES CORP
International Classes:
H03M1/78; H03M1/00; H03M1/06; H03M1/68; H03M1/74; (IPC1-7): H03K13/05
Attorney, Agent or Firm:
Kyozo Yuasa