AD9974

Rev. A | Page 42 of 52

COMPLETE REGISTER LISTING

All addresses and default values are expressed in hexadecimal. When an address contains less than 28 data bits, all remaining bits must be

written as 0s. All TESTMODE registers must be set to the specified values.

Table 22. AFE Registers

Address

Data Bit

Content

Default

Value

Update

Name

Description

0x00

[1:0]

3

SCK

STANDBY

Standby Modes.

0 = normal operation.

1= band gap reference in standby.

2, 3 = total power-down.

[2]

1

REFBUF_PWRDN

Reference Buffer for REFT and REFB Power Control.

0 = REFT/REFB internally driven.

1 = REFT/REFB not driven.

[3]

1

CLAMPENABLE

Clamp Enable Control.

0 = disable black clamp.

1 = enable black clamp.

[5:4]

0

TESTMODE

Test Operation Only. Set to 0.

[6]

0

PBLK_LVL

PBLK Level Control.

0 = blank to 0.

1 = blank to clamp level.

[7]

0

DCBYP

DC Restore Circuit Control.

0 = enable dc restore circuit during PBLK.

1 = bypass dc restore circuit during PBLK.

[9:8]

0

CDSMODE

CDS Operation.

0 = normal (inverting) CDS mode.

1 = sample and hold (SHA) mode.

2 = positive CDS mode.

3 = invalid, do not use.

[16:10]

0

TESTMODE

Test Operation Only. Set to 0.

[27:17]

Unused

Set unused bits to 0.

0x01

[1:0]

0

SCK

TESTMODE

Test Operation Only. Set to 0.

[2]

0

GRAYENCODE

Gray Coding ADC Outputs.

0 = disable.

1 = enable.

[3]

0

TESTMODE

Test Operation Only. Set to 0.

[4]

1

TESTMODE

Test Operation Only. Set to 0.

[27:5]

Unused

Set unused bits to 0.

0x02

[0]

0

SCK

TESTMODE

Test Operation Only. Set to 0.

[27:1]

Unused

Set unused bits to 0.

0x03

[23:0]

FFFFFF

SCK

TESTMODE

Test Operation Only. Set to FFFFFF.

[27:24]

Unused

Set unused bits to 0.

0x04

[1:0]

1

VD

CDSGAIN

CDS Gain Setting.

0 = −3 dB.

1 = 0 dB (default).

2 = +3 dB.

3 = +6 dB.

[27:2]

Unused

Set unused bits to 0.

0x05

[9:0]

F

VD

VGAGAIN

VGA Gain. 6 dB to 42 dB (0.035 dB per step).

[27:10]

Unused

Set unused bits to 0.

0x06

[9:0]

1EC

VD

CLAMPLEVEL

Optical Black Clamp Level. 0 LSB to 1023 LSB (1 LSB per step).

[27:10]

Unused

Set unused registers to 0.

0x07

[27:0]

0

TESTMODE

Test Operation Only. Set to 0 if this register is accessed.

0x08

[27:0]

0

TESTMODE

Test Operation Only. Set to 0 if this register is accessed.

0x09

[27:0]

0

TESTMODE

Test Operation Only. Set to 0 if this register is accessed.

0x0A

[27:0]

0

TESTMODE

Test Operation Only. Set to 0 if this register is accessed.

0x0B

[27:0]

0

TESTMODE

Test Operation Only. Set to 0 if this register is accessed.