TLV987

3-V 10-BIT 27 MSPS AREA CCD SENSOR

SIGNAL PROCESSOR

SLAS211A – MARCH 1999 – REVISED SEPTEMBER 1999

12

POST OFFICE BOX 655303

PRINCIPLES OF OPERATION

test register format

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

TB9

TB8

TB7

TB6

TB5

TB4

TB3

TB2

TB1

TB0

Default test register value =1010000000

test register description

BIT

NAME

DESCRIPTION

D9 – D6

TB9 – TB6

These four bits are used to program the internal DC bias current. The bias current

programming uses the following equation:

Ibias = 8 µA + (code) x 2 µA

Hence, Ibias varies from 8 µA (code=0000) to 38 µA (code=1111), with a linear step

of 2

µA.

The recommended setting of the code is 1010 which sets the nominal Ibias value to

28

µA.

D5, D4

TB5, TB4

Test outputs (pin 34/35 – TPM/TPP) control:

TB5

TB4

0

0 or 1 High impedance outputs at pin TPP and TPM.

1

0

Inverted internal CDS clock at pin TPP,

Inverted internal PGA clock at pin TPM.

1

1

PGA non-inverting output at pin TPP,

PGA inverting output at pin TPM.

D3

TB3

1 = Use external reference, power down internal reference

0 = Use internal reference (default).

D2

TB2

Reserved

D1, D0

TB1, TB0

Test output (pin 23, DACT) control for offset DACs:

TB1

TB0

0

0 or 1 High impedance outputs at pin DACT (default = 00)

1

0

Fine offset DAC output at pin DACT

1

1

Coarse offset DAC output at pin DACT