AD6688 datasheet(73/138 Pages) AD

73 / 138 page

Data Sheet

AD6688

Rev. 0 | Page 73 of 138

fS × 4 MODE

The fS × 4 mode adds a special packing mode on top of a JESD204B

transmitter/receiver to fix the serial lane rate at four times the

sample rate (fS).

The JESD204B link settings are L = 8; M = 2; F = 2; S = 5; N' = 12;

N = 12; CS = 0; CF = 2; and HD = 1.

However, CF = 2 is not supported by the design; therefore, the

following link parameters are used along with special packing:

L = 8; M = 2; F = 2; S = 4; N' = 16; N = 16; CS = 0; CF = 0; and

HD = 0.

In fS × 4 mode, five 12-bit ADC samples (along with an extra 4 bits)

are packed into four 16-bit JESD204B samples to create a 64-bit

frame.

The following SPI writes are necessary to place the device in

fS × 4 mode:

•

M = 2, L = 8, fS × 4 mode.

•

CS = 0, N' = 16.

•

Subclass 1 mode, N = 16.

The transmit architecture of the fS × 4 mode is shown in Figure 101,

and the receive portion is shown in Figure 102. The fS × 4 mode

only works in full bandwidth mode (Register 0x0200 = 0x00).

ADC1 SAMPLE N (12 BITS)

CONVERTER 1

SAMPLE N (16 BITS)

CONVERTER 1

SAMPLE N+1 (16 BITS)

CONVERTER 1

SAMPLE N+2 (16 BITS)

CONVERTER 1

SAMPLE N+3 (16 BITS)

S[N][15:0]

S[N + 1][15:0]

S[N + 2][15:0]

S[N + 3][15:0]

JESD204B FRAMER + PHY

(M = 2; L = 8; S = 4; F = 2; N = 16; N’ = 16; CF = 0; HD = 0)

APPLICATION

LAYER

TRANSPORT,

DATA LINK,

AND PHY

LAYERS

12-BITS

LANE 0 LANE 1 LANE 2 LANE 3 LANE 4 LANE 5 LANE 6 LANE 7

fS × 4 MODE (TRANSMIT)

1/5 RATE EXCHANGE

ADC1

SAMPLE N (12 BITS)

ADC1

SAMPLE N + 1 (12 BITS)

ADC1

SAMPLE N + 2 (12 BITS)

ADC1

SAMPLE N + 3 (12 BITS)

ADC1

SAMPLE N + 4 (12 BITS) (4 BITS)

S[N][11:0], S[N + 1][11:8]

(16 BITS)

S[N + 1][7:0], S[N + 2][11:4]

(16 BITS)

S[N + 2][3:0], S[N + 3][11:0]

(16 BITS)

S[N + 4][11:0], 0000

(16 BITS)

ADC0 SAMPLE N (12 BITS)

ADC0

CONVERTER 0

SAMPLE N (16 BITS)

CONVERTER 0

SAMPLE N + 1 (16 BITS)

CONVERTER 0

SAMPLE N + 2 (16 BITS)

CONVERTER 0

SAMPLE N + 3 (16 BITS)

S[N][15:0]

S[N + 1][15:0]

S[N + 2][15:0]

S[N + 3][15:0]

1/5 RATE EXCHANGE

ADC0

SAMPLE N (12 BITS)

ADC0

SAMPLE N + 1 (12 BITS)

ADC0

SAMPLE N + 2 (12 BITS)

ADC0

SAMPLE N + 3 (12 BITS)

ADC0

SAMPLE N + 4 (12 BITS) (4 BITS)

S[N][11:0], S[N + 1][11:8]

(16 BITS)

0000

S[N + 1][7:0], S[N + 2][11:4]

(16 BITS)

S[N + 2][3:0], S[N + 3][11:0]

(16 BITS)

S[N + 4][11:0], 0000

(16 BITS)

0000

ADC1

64-BITS

AT fS/5

64-BITS

AT fS/5

Figure 101. fS × 4 Mode (Transmit)

fS × 4 MODE (RECEIVE)

APPLICATION

LAYER

DATA LINK,

TRANSPORT,

AND PHY

LAYERS

CUSTOMER APPLICATION

S[N][15:0]

S[N + 1][15:0]

S[N + 2][15:0]

S[N + 3][15:0]

S[N][15:0]

S[N + 1][15:0]

S[N + 2][15:0]

S[N + 3][15:0]

JESD204B FRAMER + PHY

(M = 2; L = 8; S = 4; F = 2; N = 16; N’ = 16; CF = 0; HD = 0)

LANE 0 LANE 1 LANE 2 LANE 3 LANE 4 LANE 5 LANE 6 LANE 7

CONVERTER 1

SAMPLE N (16 BITS)

CONVERTER 1

SAMPLE N + 1 (16 BITS)

CONVERTER 1

SAMPLE N + 2 (16 BITS)

CONVERTER 1

SAMPLE N + 3 (16 BITS)

CONVERTER 0

SAMPLE N (16 BITS)

CONVERTER 0

SAMPLE N + 1 (16 BITS)

CONVERTER 0

SAMPLE N + 2 (16 BITS)

CONVERTER 0

SAMPLE N + 3 (16 BITS)

ADC1

SAMPLE N (12 BITS)

ADC1

SAMPLE N + 1 (12 BITS)

ADC1

SAMPLE N + 2 (12 BITS)

ADC1

SAMPLE N + 3 (12 BITS)

ADC1

SAMPLE N + 4 (12 BITS) (4 BITS)

S[N][11:0], S[N + 1][11:8]

(16 BITS)

S[N + 1][7:0], S[N + 2][11:4]

(16 BITS)

S[N + 2][3:0], S[N + 3][11:0]

(16 BITS)

S[N + 4][11:0], 0000

(16 BITS)

ADC0

SAMPLE N (12 BITS)

ADC0

SAMPLE N + 1 (12 BITS)

ADC0

SAMPLE N + 2 (12 BITS)

ADC0

SAMPLE N + 3 (12 BITS)

ADC0

SAMPLE N + 4 (12 BITS) (4 BITS)

S[N][11:0], S[N + 1][11:8]

(16 BITS)

S[N + 1][7:0], S[N + 2][11:4]

(16 BITS)

S[N + 2][3:0], S[N + 3][11:0]

(16 BITS)

S[N+4][11:0], 0000

(16 BITS)

64-BITS

AT fS/5

64-BITS

AT fS/5

0000

Figure 102. fS × 4 Mode (Receive)

AD6688 Datasheet(PDF) 73 Page - Analog Devices

AD6688 Datasheet(HTML) 73 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL