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AD9843A

–14–

REV. 0

Table VIII. VGA Gain Register Used for AUX2-Mode

MSB

LSB

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

Gain (dB)

X

0

X

X

X

X

X

X

X

X

X

0.0

1

0

0

0

0

0

0

0

0

0

0.0

1

1

1

1

1

1

1

1

1

1

18.0

AUX1IN

0.1

F

VGA GAIN

REGISTER

ADC

VGA

10

5k

0.4V

0.4V

INPUT SIGNAL

??V

0.8V

0.4V

MIDSCALE

0dB TO 36dB

Figure 14. AUX1 Circuit Configuration

0dB TO 18dB

8

AUX2IN

BUFFER

0.1

F

VIDEO

SIGNAL

9

CLAMP LEVEL

LPF

VGA GAIN

REGISTER

ADC

VGA

VIDEO CLAMP

CIRCUIT

CLAMP LEVEL

REGISTER

Figure 15. AUX2 Circuit Configuration

CCD

CCDIN

BUFFER

V

OUT

0.1

F

ADC

OUT

REGISTER

DATA

SERIAL

INTERFACE

DIGITAL

OUTPUTS

DIGITAL IMAGE

PROCESSING

ASIC

TIMING

GENERATOR

V-DRIVE

CCD

TIMING

CDS/CLAMP
TIMING

AD9843A

Figure 16. System Applications Diagram

Содержание AD9843A

Страница 1: ...with 6 Bit Resolution 2 dB to 36 dB 10 Bit Variable Gain Amplifier VGA Low Noise Clamp Circuits Analog Preblanking Function 10 Bit 20 MSPS A D Converter Auxiliary Inputs with VGA and Input Clamp 3 Wir...

Страница 2: ...cale Input Voltage 2 0 V Data Output Coding Straight Binary VOLTAGE REFERENCE Reference Top Voltage VRT 2 0 V Reference Bottom Voltage VRB 1 0 V Specifications subject to change without notice DIGITAL...

Страница 3: ...2 dB See Page 13 for Gain Equations Max Gain VGA Code 1023 36 dB BLACK LEVEL CLAMP Clamp Level Resolution 256 Steps Clamp Level Measured at ADC Output Min Clamp Level 0 LSB Max Clamp Level 63 75 LSB...

Страница 4: ...ODE SPECIFICATIONS Parameter Min Typ Max Unit POWER CONSUMPTION 60 mW MAXIMUM CLOCK RATE 20 MHz INPUT BUFFER Same as AUX1 MODE VGA Max Output Range 2 0 V p p Gain Control Resolution 512 Steps Gain Sel...

Страница 5: ...UTION ESD electrostatic discharge sensitive device Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection Although the AD98...

Страница 6: ...s Reference Level 22 SHD DI CDS Sampling Clock for CCD s Data Level 23 CLPDM DI Input Clamp Clock Input 25 26 35 AVSS P Analog Ground 27 AVDD1 P Analog Supply 28 BYP1 AO Internal Bias Level Decoupling...

Страница 7: ...calculated in LSB and represents the rms noise level of the total signal chain at the specified gain setting The output noise can be converted to an equivalent voltage using the relationship 1 LSB AD...

Страница 8: ...60 80 90 15 VDD 3 3V VDD 3 0V VDD 2 7V TPC 1 Power vs Sample Rate 0 1000 400 200 600 800 0 0 5 0 5 0 25 0 25 TPC 2 Typical DNL Performance Typical Performance Characteristics VGA GAIN CODE LSB 4 2 0 0...

Страница 9: ...IVE PIXELS CLPOB CLPDM OPTICAL BLACK PIXELS HORIZONTAL BLANKING DUMMY PIXELS EFFECTIVE PIXELS PBLK NOTES 1 CLPOB AND CLPDM WILL OVERWRITE PBLK PBLK WILL NOT AFFECT CLAMP OPERATION IF OVERLAPPING CLPDM...

Страница 10: ...OCCURS ON SL RISING EDGE Figure 8 Serial Write Operation SDATA SCK SL RNW TEST 1 0 A0 A1 D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 tDS tDH tLS tLH NOTES 1 RNW READ NOT WRITE SET HIGH FOR READ OPERATION 2 TES...

Страница 11: ...nts Default Value x080 MSB LSB D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Clamp Level LSB X X X 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 25 0 0 0 0 0 0 1 0 0 5 1 1 1 1 1 1 1 0 63 5 1 1 1 1 1 1 1 1 63 75 Table V Con...

Страница 12: ...ee Tables V and VI for more details A CDS gain of 4 dB provides some front end signal gain and improves the overall signal to noise ratio This gain setting works very well in most applications and the...

Страница 13: ...Interface Timing and Inter nal Register Description section When the loop is disabled the Clamp Level Register may still be used to provide pro grammable offset adjustment Horizontal timing is shown i...

Страница 14: ...NAL V 0 8V 0 4V MIDSCALE 0dB TO 36dB Figure 14 AUX1 Circuit Configuration 0dB TO 18dB 8 AUX2IN BUFFER 0 1 F VIDEO SIGNAL 9 CLAMP LEVEL LPF VGA GAIN REGISTER ADC VGA VIDEO CLAMP CIRCUIT CLAMP LEVEL REG...

Страница 15: ...ins 25 through 39 This will ensure that all analog decoupling capacitors provide the lowest possible impedance path between the power and bypass pins and their respective ground pins All decoupling ca...

Страница 16: ...inches and mm 48 Lead LQFP ST 48 TOP VIEW PINS DOWN 1 12 13 25 24 36 37 48 0 019 0 5 BSC 0 276 7 00 BSC SQ 0 011 0 27 0 006 0 17 0 354 9 00 BSC SQ 0 063 1 60 MAX 0 030 0 75 0 018 0 45 0 008 0 2 0 004...

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