TEST PATTERNS

ADS5271

SBAS313C – JUNE 2004 – REVISED JANUARY 2009...................................................................................................................................................... www.ti.com

SERIAL INTERFACE REGISTERS

ADDRESS

DATA

DESCRIPTION

REMARKS

D7

D6

D5

D4

D3

D2

D1

D0

0

0

0

0

LVDS BUFFERS (Register 0)

All Data Outputs

0

0

Normal ADC Output

(default after reset)

0

1

Deskew Pattern

1

0

Sync Pattern

See Test Patterns

1

1

Custom Pattern

0

0

Output Current in LVDS = 3.5mA

(default after reset)

0

1

Output Current in LVDS = 2.5mA

1

0

Output Current in LVDS = 4.5mA

1

1

Output Current in LVDS = 6.0mA

0

0

0

1

CLOCK CURRENT (Register 1)

0

X

X

0

Default LVDS Clock Output Current

IOUT = 3.5mA (default)

0

X

X

1

2x LVDS Clock Output Current(1)

IOUT = 7.0mA

0

0

0

1

LSB/MSB MODE (Register 1)

0

0

X

X

LSB First Mode

(default after reset)

0

1

X

X

MSB First Mode

0

0

1

0

POWER-DOWN ADC CHANNELS

(Register 2)

X

X

X

X

Example: 1010 Powers Down

Power-Down Channels 1 to 4; D3 is

Channels 4 and 2 and

for Channel 4 and D0 for Channel 1

Keeps Channels 1 and 3 Active

0

0

1

1

POWER-DOWN ADC CHANNELS

(Register 3)

X

X

X

X

Power-Down Channels 5 to 8; D3 is

for Channel 8 and D0 for Channel 5

CUSTOM PATTERN (Registers 4–6)

D3

D2

D1

D0

Bits for Custom Pattern

See Test Patterns

0

1

0

0

X

X

X

X

0

1

0

1

X

X

X

X

0

1

1

0

X

X

X

X

(1)

Output current drive for the two clock LVDS buffers (LCLKP and LCLKN and ADCLKP and ADCLKN) is double the output current setting

programmed in register 0. The current drive of the data buffers remains the same as the setting in register 0.

Serial Output(1)

LSB

MSB

ADC Output(2)

D0

D1

D2

D3

D4

D5

D6

D7

D8

D9

D10

D11

Deskew Pattern

1

0

1

0

1

0

1

0

1

0

1

0

Sync Pattern

0

0

0

0

0

0

1

1

1

1

1

1

Custom Pattern(3)

D0(4)

D1(4)

D2(4)

D3(4)

D0(5)

D1(5)

D2(5)

D3(5)

D0(6)

D1(6)

D2(6)

D3(6)

(1)

The serial output stream comes out LSB first by default.

(2)

D11...D0 represent the 12 output bits from the ADC.

(3)

D0(4) represents the content of bit D0 of register 4, D3(6) represents the content of bit D3 of register 6, etc.

10

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