PI6050D Data Sheet

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PI6050D Unique Features

There are six unique features incorporated into the PI6050D which improve the sensor’s performance.

1.

Pixel-to-Pixel Offset Cancellation Circuit

The sensor employs a pixel-to-pixel offset cancellation circuit, which reduces the Fix Pattern Noise (FPN), and

amplifier offsets. In addition, this innovative circuit design greatly improves the optical linearity and low noise

sensitivity.

2.

Parallel Integrate, Transfer and Hold

The sensor has a parallel integrate, transfer and hold feature, which allows the sensor to be read out while

photon integration is taking place. These features are approached through the use of an integrate-and-hold cell,

located at each pixel site. Each pixel’s charge is read from its storage site as the sensor’s shift register

sequentially transfers each pixel’s charge onto a common video line.

3.

Dual Scan Initiation Inputs, GBST and SI

Each sensor has two scan initiation inputs, the Global Start Pulse (GBST) and the Start Pulse (SI), which are

compatible with standard 3.3V CMOS clocks. These clocks help to reduce the sensor-to-sensor transition Fix

Pattern Noise by initializing and preprocessing all sensors simultaneously before they start their readout scan.

The internal shift register starts the scan after GBST is clocked in on the falling edge of the Clock input (CLK).

The Start Input Control (SIC) selects the first sensor in a sequence of cascaded sensors to operate with 55 clock

cycles of delay by connecting it to Vdd and to Ground for all subsequent sensors. Then, only the first sensor

clocks out 110 inactive pixels (55 clocks cycles) before accessing its first active pixel. During these 55 clock

cycles, the first sensor and all of the subsequent cascaded sensors cycle through their pre-scan initialization

process. After initialization, only the first sensor starts its read cycle with its first-active pixel appearing on the 56

th

clock cycle. The second and subsequent sensors await the entry of their Start Pulse (SI). Furthermore, the first

sensor’s Start Pulse (SI) is left unconnected, while the subsequent sensors all have their Start Pulse’s (SI)

connected to the SO of their respective preceding sensor. The external scan Start Pulse (SI) is connected to all

of the sensors' Global Start Pulse (GBST) inputs.

For example in the 1200 dpi mode, when the first sensor completes its scan, its End-Of-Scan (SO) appears on

the falling edge of 389

continuous pixel readout between sensors in a module. This SO enters as the SI clock of the second and

subsequent sensors; hence all subsequent sensors will start their register scan after each of the preceding

sensors completes its scan.

4.

Power Saving

Each sensor incorporates a power-saving feature such that each chips amplifier is only turned on when its pixels

are ready to be read out.

5.

Common Reference Voltage between Cascaded Sensors

Each sensor has an input/output bias control (VREF), which serves as an offset voltage reference. Each bias

control pad is connected to an internal bias source and tied to its own amplifier’s reference bias input. In

operation, these pads on every sensor are connected together. Each sensor then “shares” the same bias level to

maintain a constant bias among all of the sensors.

6.

Selectable Resolutions of 600 dpi or 1200 dpi

The Switch Control input (SC) is connected to Ground or to Vdd to set the sensor to operate in the 600 dpi or

1200 dpi mode, respectively. In the 1200 dpi mode, all 688 pixels are clocked out, whereas in the 600 dpi mode,

pixels 1 and 2 are combined, 3 and 4 are combined and so on up to pixels 687 and 688 being combined. One

half of the pixel amplifiers and one half of the scanning register are then disabled. As a result, sensitivity in the

600 dpi mode will be twice that of the 1200 dpi mode. The 600 dpi readout time will be approximately half of the

1200 dpi readout time. Unlike a CCD array, both the 600 dpi and 1200 dpi arrays can operate with the same

clock frequency.

Page 3 of 15, PI6050D_rev A, Revised 1-31-05