cxd2310ar Sony Electronics, cxd2310ar Datasheet - Page 11

• Manufacturer Part Number: cxd2310ar
• Description: 10-bit 20msps Video A/d Converter
• Manufacturer: Sony Electronics

1. Calibration Function
In order to achieve superior linearity, the CXD2310AR has a built-in calibration circuit. In order to eliminate the
necessity for the externally input calibration pulse required by the earlier CXD2310R, a startup calibration
function and an auto calibration pulse generation function have been newly added to the CXD2310AR. Fig. 1
shows a block diagram of the calibration pulse generation circuit.
(1) Startup Calibration Function
Over 600 calibration pulses are needed to complete the initial calibration process when the power is first
supplied to the IC. The startup calibration function automatically generates these pulses internally and
completes the initial calibration process.
For example, if the main clock frequency is 14.3MHz, the time required for startup calibration is 18ms.
Sence Amp 2
Sence Amp 1
CLR
[V]
2.5
5
0
When RESET = High and CE = Low
RESET
AV
AV
VRB
VRT
CLK
1V
CE
DD
SS
Sence
Amp 2
Sence
Amp 1
Startup calibration time = main clock cycle
AV
VRB
VRT
[ t ]
Fig. 1. Calibration Pulse Generation Circuit
DD
16
1
The following five conditions must be satisfied to initiate the
startup calibration function.
Once all five of these conditions have been met, the calibration
pulses are generated. The pulses are generated by counting 16
main clock cycles on a 14-bit counter and closing the gate when
the carry-out occurs. Therefore, the time required for startup
calibration after the above five conditions have been met is
determined by the following formula:
14 bit
Counter
24 bit
Counter
a) The voltage between AV
b) The voltage between VRT and VRB is approximately 1V
c) The RESET pin (Pin 15) must is high.
d) The CE pin (Pin 24) must is low.
e) Condition b is met after condition a.
CLR
CLR
2.5V or more.
or more.
– 11 –
SEL
CAL
CO
CO
AV
D Q
CLR
DD
16
16,384
DD
and AV
OUT
SS
is approximately
CXD2310AR