MCM20027IBMN View Datasheet(PDF) - Motorola => Freescale

Part Name

Description

Manufacturer

MCM20027IBMN

Color SXGA Digital Image Sensor 1280 x 1024 pixel progressive scan solid state image sensor with integrated CDS/PGA/ADC, digital programming, control, timing, and pixel correction features

Motorola => Freescale 

MOTOROLA

SEMICONDUCTOR TECHNICAL DATA

ImageMOS

1.0 MCM20027 Overview

The MCM20027 is a solid state CMOS Active CMOS

Imager (ACITM) that integrates the functionality of a

complete analog image acquisition, digitizer, and digital

signal processing system on a single chip. The image

sensor comprises a format pixel array with 1280x1024

active elements. The image size is fully programmable

to user defined windows of interest. The pixels are on a

6.0µm pitch. High sensitivity and low noise are a char-

acteristic of the pinned “shared diffusion” photodiode ar-

chitecture utilized in the pixels. Standard microlenses

further enhance the sensitivity. The sensor is available

with Bayer patterned Color Filter Arrays (CFAs) for color

output or as a monochrome imager.

Integrated timing and programming controls allow video

or still image capture modes. Frame rates are program-

mable while keeping Master Clock frequency constant.

User programmable row and column start/stop allow

windowing to a minimum 1x1 pixel window (see “Active

Window of Interest Control” on page 12). Windowing

can also be performed by subsampling in multiple pixel

increments to allow digital zoom (see “Active Window

Sub-sampling Control” on page 12).

The analog video output of the pixel array is processed

by an on chip analog signal processing pipeline. Corre-

lated Double Sampling (see “Correlated Double Sam-

pling (CDS)” on page 15) eliminates the sensor reset

noise without the need to capture and subtract a reset

frame per live video frame. The Frame Rate Clamp

(FRC) enables real time optical black level calibration

and offset correction (see “Frame Rate Clamp (FRC)”

on page 15). The programmable analog gain consists of

exposure or global gain to map the signal swing to the

ADC input range, and white balance gain to perform col-

or white balance in the analog domain. The ASP signal

chain consists of :

(1) Column op-amp(1.5X fixed gain)

(2) Column DOVA (1.5X fixed gain)

(3) White Balance PGA (0.88-2.82X)

(4) Global PGA (0.67X - 5.92X)

(5) Global DOVA (2.0X fixed gain)

These Digitally Programmable Amplifiers (DPGAs) al-

low real time color gain correction for Auto White Bal-

ance (see “White Balance Control PGA” on page 16) as

well as global gain adjustment (see “Exposure Global

Gain PGA” on page 16); offset calibration (see “Pro-

grammable Per-Column Offset” on page 16 and “Global

Digital Offset Voltage Adjust (DOVA)” on page 19) can

be done on a per column basis and globally. This per-

column offset correction can be applied by using stored

values in the on chip registers. A 10-bit Redundant

Signed Digit (RSD) ADC converts the analog data to a

10-bit digital word stream. The fully differential analog

signal processing pipeline serves to improve noise im-

munity, signal to noise ratio, and system dynamic

range.

The sensor uses an industry standard two line I2C com-

plaint serial interface. (see page 26). The MCM20027

operates with a single 3.3V power supply ( see “Electri-

cal Characteristics” on page 53) with no additional bias-

es and requires only a single Master Clock for operation

upto 13.5MHz. It is housed in a 48 pin ceramic LCC

package (see “MCM20027 Packaging Information” on

page 69).

The MCM20027 is designed taking into consideration

interfacing requirements to standard video encoders. In

addition to the 10 bit bayer encoded data stream, the

sensor outputs the valid frame, line and pixel sync sig-

nals needed for encoding. The sensor interfaces with a

variety of commercially available video image proces-

sors to allow encoding into various standard video for-

mats.

The MCM20027 is an elegant and extremely flexible

single chip solution that simplifies a system designer’s

tasks of image sensing, processing, digital conversion,

and digital signal processing to a high performance, low

cost, low power IC. One that supports among others a

wide range of low power, portable consumer digital im-

aging applications.

2.0 MCM20027 Architecture

2.1 Pixel Architecture

The MCM20027 ImageMOSTM (1) sensor comprises of

a 1280 x 1024 active pixel array and supports progres-

sive scan mode.

The MCM20027 utilizes the Kodak patented “Shared

Floating Diffusion” pixel design 3. This design enables

two adjacent Row pixels‘ photodiodes to share the

same floating diffusion transistor. (see Figure 2, on

page 8).

The basic operation of the pixel relies on the photoelec-

tric effect where due to its physical properties silicon is

able to detect photons of light. The photons generate

electron-hole pairs in direct proportion to the intensity

1. ImageMOS is a Motorola trademark

2. Patents held jointly by Motorola and Kodak

3. Kodak Patent pending

Revision 8.4 - 24 Oct 2002: MCM20027

MOTOROLA

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