CCD143A Datasheet, PDF (3/12 Pages) List of Unclassifed Manufacturers – 2048-Element High Speed Linear Image Sensor

CCD143A
2048-Element High Speed Linear Image Sensor
Transfer Clock X — The transfer clock is the voltage
waveform applied to the transfer gate to move the
accumulated charge from the image sensor elements to the
CCD transport shift registers.
Transport Clock T — The transport clock is the clock
applied to the gates of the CCD transport shift registers to
move the charge-packets received from the image sensor
elements to the gate charge-detector/amplifiers.
Gate Charge-Detector/Amplifier — These are the
output circuits of the CCD143A which receive the charge
packets from the CCD transport shift registers and provide a
signal voltage proportional to the size of each charge-packet
received. Before each new charge-packet is sensed, an
internal reset clock returns the charge-detector voltages to a
fixed base level.
Sample-and-Hold Clock SHC — This is an internally or
externally supplied voltage waveform applied to the sample-
and-hold gate in the amplifiers to create a continuous
sampled video signal at the output. On-chip sample-and-hold
operation is achieved by connecting SHGA to SHCA and SHGB
to SHCB.
If the internal (on chip) sample-and-hold clocks are not used,
the on-chip sample-and-hold clock driver circuits can be
depowered, which greatly reduces on-chip power
consumption. To disable (turn off) these drivers, VGG is tied
to VDD/VCD. The on-chip SH clock drivers are enabled by
connecting VCG to VSS.
Optional External Reset Clocks RA and RB — Dynamic
Range and S/N Ratio may be maximized by double-
correlated sampling off-chip of the device output. This
requires externally-supplied reset clocks for the on-chip
amplifiers. Pins 5 and 21 are RA and RB, respectively. If this
feature is not desired, both pins should be tied to VCD/VDD,
which enables the internally generated reset circuits.
Dark Reference — Video output level generated from
sensing elements covered with opaque metallization
provides a reference voltage equivalent to device operation
in the dark. This permits use of external dc restoration
circuitry.
White Reference — Video output level generated by on-
chip circuitry provides a reference voltage permitting external
automatic gain control circuitry to be used. The reference
voltage is produced by charge-injection under the control of
the electrical input bias voltage (VEI). The amplitude of the
reference is typically 80% of the saturation output voltage.
Isolation Cell — This is a site on-chip producing an
element in the video output that serves as a buffer between
valid video data and dark reference signals. The output from
an isolation cell contains no valid video information and
should be ignored.
Dynamic Range — The dynamic range is the saturation
exposure divided by the peak-to-peak noise equivalent
exposure. (This does not take into account any dark signal
components.) Dynamic range is sometimes defined in terms
of rms noise. To compare the two definitions a factor of four
to six is generally appropriate in that peak-to-peak noise is
approximately equal to four to six times rms noise.
Peak-to-Peak Noise Equivalent Exposure — This is
the exposure level which gives an output signal equal to the
peak-to-peak noise level at the output in the dark.
Saturation Exposure — Saturation exposure is the
minimum exposure level that will produce a saturated output
signal. Exposure is equal to the light intensity times the
photosite integration time.
Charge Transfer Efficiency — This is the percentage
of valid charge information that is transferred between each
successive stage of the transport registers.
Spectral Response Range — This is the spectral band
in which the response per unit of radiant power is more than
10% of the peak response.
Responsivity — Responsivity is the output signal voltage
per unit exposure for a specified spectral type of radiation.
Responsivity equals output voltage divided by exposure
level.
Dark Signal — This is the output signal in the dark
caused by thermally generated electrons which is a linear
function of integration time and highly sensitive to
temperature. (See accompanying photos for details of
definition.)
Total Photoresponse Non-Uniformity — This is the
difference in the response levels between the most and least
sensitive elements under uniform illumination. (See
accompanying photos for details of definition.)
Integration Time — The time interval between the falling
edges of any two successive transfer pulses X is the
integration time shown in the Timing Diagram. The
integration time is the time allowed for the photosites to
collect charge.
Pixel — Picture element (photosite).
1801 McCarthy Blvd. • Milpitas CA 95035 • [phone] • www.fairchildimaging.com • Rev A • 3 of 12