A CMOS-only R-2R ladder D/A converter for image sensor applications

Author

Domingues, Suzana ; Braga, Leo H C ; Mesquita, Antonio C.

Author_Institution

Lab. de Projeto de Circuitos Integrados, Univ. Fed. do Rio de Janeiro, Rio de Janeiro, Brazil

fYear

2009

fDate

6-8 Nov. 2009

Firstpage

1

Lastpage

6

Abstract

This paper presents a monotonic CMOS-only R-2R ladder D/A converter to be used in a single-slope A/D converter for image sensor applications. It employs complementary switches with dummy transistors in the ladder to reduce the glitch energy of the output. This does not affect the monotonicity of the ladder and adds less than 0.5% to the total mismatch variations. The estimate of the mismatch variations results in 99.5% of probability for monotonic behavior of the fabricated chips. The complete D/A converter was implemented in a standard 0.35 Â¿m CMOS process and occupies an area of only 0.03 mm². Post-layout simulations showed that the DNL graph does not exceed the range of Â± 1 LSB, which indicates a monotonic behavior of the D/A converter. The average power consumption for the conversion of a full digital cycle is 0.55 mW.

Keywords

CMOS image sensors; digital-analogue conversion; CMOS-only R-2R ladder D/A converter; image sensor applications; power 0.55 mW; size 0.35 mum; transistor mismatch; CMOS image sensors; CMOS process; Circuits; Energy consumption; Image converters; Image sensors; Ionizing radiation sensors; Resistors; Silicon; Voltage; CMOS image sensors; D/A conversion; I/V conversion; R-2R ladder; transistor mismatch;

fLanguage

English

Publisher

ieee

Conference_Titel

Signals, Circuits and Systems (SCS), 2009 3rd International Conference on

Conference_Location

Medenine

Print_ISBN

978-1-4244-4397-0

Electronic_ISBN

978-1-4244-4398-7

Type

conf

DOI

10.1109/ICSCS.2009.5414155

Filename

5414155