AD9945(RevC) データシートの表示（PDF） - Analog Devices
部品番号
コンポーネント説明
メーカー
AD9945 Datasheet PDF : 14 Pages
| |||
Internal Power-On Reset Circuitry
After power-on, the AD9945 will automatically reset all internal
registers and perform internal calibration procedures. This takes
approximately 1 ms to complete. During this time, normal clock
signals and serial write operations may occur. However, serial
register writes will be ignored until the internal reset operation
is completed.
Required Start-Up Write
During power-up of the AD9945, 0x838 must be written into
Register 0xD for proper start-up operation.
Grounding and Decoupling Recommendations
As shown in Figure 11, a single ground plane is recommended for
the AD9945. This ground plane should be as continuous as
possible. This will ensure that all analog decoupling capacitors
SERIAL
3
INTERFACE
D0
D1
AD9945
provide the lowest possible impedance path between the power
and bypass pins and their respective ground pins. All decoupling
capacitors should be located as close as possible to the package
pins. A single clean power supply is recommended for the AD9945,
but a separate digital driver supply may be used for DRVDD
(Pin 11). DRVDD should always be decoupled to DRVSS (Pin 12),
which should be connected to the analog ground plane. If the digital
outputs (Pins 1 to 10, 31, and 32) must drive a load larger than 20 pF,
buffering is recommended to reduce digital code transition noise.
Alternatively, placing series resistors close to the digital output pins
may also help reduce noise.
D2 1
D3 2
D4 3
D5 4
D6 5
D7 6
D8 7
D9 8
PIN 1
IDENTIFIER
AD9945
TOP VIEW
(Not to Scale)
24 REFB
23 REFT
22 CCDIN
21 AVSS
20 AVDD
19 SHD
18 SHP
17 CLPOB
1.0F
1.0F
0.1F
0.1F
CCDIN
3V
ANALOG
SUPPLY
DATA 12
OUTPUTS
3V
DRIVER
SUPPLY
0.1F
0.1F
3V
ANALOG
SUPPLY
5
CLOCK
INPUTS
NC = NO CONNECT
NOTE
THE EXPOSED PAD ON THE BOTTOM OF THE AD9945 SHOULD BE
SOLDERED TO THE GND PLANE OF THE PRINTED CIRCUIT BOARD
Figure 11. Recommended Circuit Configuration for CCD Mode
REV. C
–13–
Share Link: 