ANALOG DEVICES AD8159 Service Manual

www.BDTIC.com/ADI

3.2 Gbps

FEATURES

Port level 2:1 mux/1:2 demux
Each port consists of 4 lanes
Each lane runs from dc to 3.2 Gbps, independent

of the other lanes

Compensates over 40 inches of FR4 at 3.2 Gbps through

o levels of input equalization, or four levels of output

tw

pre-emphasis
Accepts ac- or dc-coupled differential CML inputs
Low deterministic jitter, typically 20 ps p-p
Low random jitter, typically 1 ps rms
BER < 10
On-chip termination
Reversible inputs and outputs on one port
Unicast or bicast on 1:2 demux function
Port level loopback capability
Single lane switching capability

3.3 V core supply
Flexible I/O supply down to 2.5 V
Low power, typically 1 W in basic configuration
100-pin TQFP_EP

−40°C to +85°C operating temperature range

APPLICATIONS

Low cost redundancy switch
SONET OC48/SDH16 and lower data rates
XAUI (10 Gigabit Ethernet) over backplane
Gigabit Ethernet over backplane
Fibre channel 1.06 Gbps and 2.125 Gbps over backplane
Infiniband over backplane
PCI-Express over backplane

GENERAL DESCRIPTION

The AD8159 is an asynchronous, protocol agnostic, quad-lane
2:1 switch with a total of 12 differential PECL/CML-compatible
inputs and 12 differential CML outputs. The operation of this
product is optimized for NRZ signaling with data rates up to

3.2 Gbps per lane. Each lane offers two levels of input
equalization and four levels of output pre-emphasis.

-16

Quad Buffer Mux/Demux

AD8159

FUNCTIONAL BLOCK DIAGRAM

EQUALIZATION

Figure 1.

TRANSMIT

PRE-

EMPHASIS

EQ

RECEIVE

I/O

CROSS-

OVER

SWITCH

CONTROL

LOGIC

OUT_C[3:0]/
IN_C[3:0]

IN_C[3:0]/
OUT_C[3:0]

LB_A
LB_B
LB_C
PE_A[1:0]
PE_B[1:0]
PE_C[1:0]
EQ_A
EQ_B
EQ_C
SEL[3:0]
BICAST
REVERSE_C

RECEIVE

EQUALIZATION

IN_A[3:0]

IN_B[3:0]

OUT_A[3:0]

OUT_B[3:0]

EQ

EQ

TRANSMIT

PRE-

EMPHASIS

AD8159

2:1

1:2

QUAD

2:1

MULTIPLEXER/

1:2

DEMULTIPLEXER

The main application of the AD8159 is to support redundancy
on both the backplane side and the line interface side of a serial
link. The device has unicast and bicast capability, so it is
configurable to support either 1 + 1 or 1:1 redundancy.

The AD8159 supports reversing the output and input pins on
o

ne of its ports, which helps to connect two ASICs with

opposite pinouts.

05611-001

The AD8159 consists of four multiplexers and four demulti­p

lexers, one per lane. Each port is a 4-lane link, and each lane
runs up to a 3.2 Gbps data rate independent of the other lanes.
The lanes are switched independently using the four select pins,

The AD8159 is also used for testing high speed serial links by

uplicating incoming data and sending it to the destination port

d
and to test equipment simultaneously.

SEL[3:0]; each select pin controls one lane of the port. The
AD8159 has low latency and very low lane-to-lane skew.

Rev. A

Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] ©2006 Analog Devices, Inc. All rights reserved.

AD8159

www.BDTIC.com/ADI

TABLE OF CONTENTS

Features.............................................................................................. 1

Theory of Operation ...................................................................... 15

Applications....................................................................................... 1

General Description ......................................................................... 1

Functional Block Diagram .............................................................. 1

Revision History ............................................................................... 2

Specifications..................................................................................... 3

Absolute Maximum Ratings............................................................ 4

ESD Caution.................................................................................. 4

Pin Configuration and Function Descriptions............................. 5

Typical Performance Characteristics ............................................. 7

Evaluation Board Simplified Block Diagrams ............................ 12

Test Circuits..................................................................................... 13

REVISION HISTORY

4/06—Rev. 0 to Rev. A

Changes to Applications Section .................................................... 1

Changes to Table 5.......................................................................... 15

Updates to Outline Dimensions ...................................................22

Changes to Ordering Guide.......................................................... 22

Input Equalization (EQ) and Output Pre-Emphasis (PE).... 15

Loopback ..................................................................................... 16

Port C Reverse (Crossover) Capability.................................... 17

Applications..................................................................................... 18

Interfacing to the AD8159............................................................. 19

Termination Structures.............................................................. 19

Input Compliance....................................................................... 19

Output Compliance ................................................................... 20

Outline Dimensions....................................................................... 22

Ordering Guide .......................................................................... 22

9/05—Revision 0: Initial Version

Rev. A | Page 2 of 24

AD8159

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SPECIFICATIONS

VCC = +3.3 V, VEE = 0 V, RL = 50 Ω, basic configuration,1 data rate= 3.2 Gbps, input common-mode voltage = 2.7 V, differential input
swing = 800 mV p-p, @ T

Table 1.

Parameter Conditions Min Typ Max Unit

DYNAMIC PERFORMANCE

Data Rate/Channel (NRZ) DC 3.2 Gbps
Deterministic Jitter Data rate = 3.2 Gbps; see Figure 21 20 ps p-p
Random Jitter RMS; see Figure 24 1 ps
Propagation Delay Input to output 600 ps
Lane-to-Lane Skew 100 ps
Switching Time 5 ns
Output Rise/Fall Time 20% to 80% 100 ps

INPUT CHARACTERISTICS

Input Voltage Swing Differential, V
Input Voltage Range Common mode, VID = 800 mV p-p;3 see Figure 25 VEE + 1.8 VCC + 0.3 V
Input Bias Current 4 μA
Input Capacitance 2 pF

OUTPUT CHARACTERISTICS

Output Voltage Swing Differential, PE = 0 800 mV p-p
Output Voltage Range Single-ended absolute voltage level; see Figure 26 VCC − 1.6 VCC + 0.6 V
Output Current Port A/B, PE_A/B = 0 16 mA
Port C, PE_C = 0 20 mA
Port A/B, PE_A/B = 3 28 mA
Port C, PE_C = 3 32 mA
Output Capacitance 2 pF

TERMINATION CHARACTERISTICS

Resistance Differential 90 100 110 Ω
Temperature Coefficient 0.15 Ω/°C

POWER SUPPLY

Operating Range

V

CC

Supply Current

I

CC

I

= I

+ I

TTO

TTOI

+ I

I/O

Supply Current

I

CC

I

= I

+ I

TTO

TTOI

+ I

I/O

THERMAL CHARACTERISTICS

Operating Temperature Range −40 +85 °C
θJA Still air 29 °C/W
θJB Still air 16 °C/W
θJC Still air 13 °C/W

LOGIC INPUT CHARACTERISTICS

Input High (VIH) 2.4 VCC V
Input Low (VIL) VEE 0.8 V

1

Bicast off, loopback off on all ports, pre-emphasis off on all ports, equalization set to minimum on all ports.

2

V

= input common-mode voltage.

ICM

3

VID = input differential peak-to-peak voltage swing.

= +25°C, unless otherwise noted.

A

VEE = 0 V 3.0 3.3 3.6 V
Basic configuration1, dc-coupled inputs/outputs, 400 mV I/O

swings (800 mV p-p differential), 50 Ω far end terminations

+ I

TTI

TTIO

BICAST = 1, PE = 3 on all ports, dc-coupled inputs/outputs,
400 mV I/O swings (800 mV p-p differential), 50 Ω far end

+ I

TTI

TTIO

terminations

= VCC − 0.6 V;2 see Figure 22 200 2000 mV p-p

ICM

175 mA
144 mA

255 mA
352 mA

Rev. A | Page 3 of 24

AD8159

www.BDTIC.com/ADI

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating
VCC to VEE 3.7 V
V

V

TTI

V

V

TTIO

V

V

TTO

V

V

TTOI

Internal Power Dissipation
Differential Input Voltage 2.0 V
Logic Input Voltage VEE − 0.3 V < VIN < VCC + 0.6 V
Storage Temperature Range
Lead Temperature

+ 0.6 V

CC

+ 0.6 V

CC

+ 0.6 V

CC

+ 0.6 V

CC

4.26 W

−65°C to +125°C
300°C

Stresses above those listed under Absolute Maximum Ratings

y cause permanent damage to the device. This is a stress

ma
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.

ESD CAUTION

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 this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.

Rev. A | Page 4 of 24

AD8159

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PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

CC

EE

TTOI

EE

CC

EE

TTIO

EE

V

OIP_C098OIN_C097V

OIP_C195OIN_C194V

OIP_C292OIN_C291V

OIP_C389OIN_C388V

IOP_C086ION_C085V

IOP_C183ION_C182V

100

99

96

93

90

87

84

IOP_C280ION_C279V

81

IOP_C377ION_C376V

78

CC

1

NC

V

CC

V

EE

V

EE

V

EE

PE_A0

PE_A1

PE_B0

PE_B1

PE_C0

PE_C1

REVERSE_C

V

CC

ON_A3

OP_A3

V

EE

ON_A2

OP_A2

V

TTO

ON_A1

OP_A1

V

EE

ON_A0

OP_A0

V

CC

NC = NO CONNE CT

NOTES

1. THE AD8159 TQFP HAS AN EXPOSED PADDLE (ePAD) ON THE UNDERSIDE OF THE PACKAGE WHICH AIDS
IN HEAT DISS IPATIO N. THE ePAD M UST BE ELE CTRICALL Y CONNECTE D TO THE V
TO MEET THERMAL SPECIFICATIONS.

PIN 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

EE

CC

V

IP_A3

IN_A3

TTI

V

V

IP_A2

IN_A2

IN_A1

34

IP_A1

AD8159

TOP VIEW

(Not to Scale)

35

36

EE

V

IN_A0

37

38

39

40

41

42

43

44

45

46

47

48

EE

CC

V

V

IP_A0

OP_B3

ON_B3

OP_B2

ON_B2

EE

TTO

V

V

OP_B1

ON_B1

ON_B0

SUPPLY PLANE IN ORDER

EE

75

V

CC

74

EQ_A

73

EQ_B

72

EQ_C

71

SEL3

70

SEL2

69

SEL1

68

SEL0

67

LB_C

66

LB_B

65

LB_A

64

BICAST

63

V

CC

62

IP_B0

61

IN_B0

60

V

EE

59

IP_B1

58

IN_B1

57

V

TTI

56

IP_B2

55

IN_B2

54

V

EE

53

IP_B3

52

IN_B3

51

V

CC

49

50

CC

V

OP_B0

05611-002

Figure 2. Pin Configuration

Table 3. Pin Function Descriptions

Pin No. Mnemonic Type Description

1 NC N/A No connect
2, 13, 25, 26, 38, 50, 51, 63, 75, 76, 88, 100 VCC Power Positive supply
3 to 5, 16, 22, 29, 35, 41, 47, 54, 60, 79, 85, 91, 97 V
6 PE_A0 Control
7 PE_A1 Control
8 PE_B0 Control
9 PE_B1 Control
10 PE_C0 Control
11 PE_C1 Control
12 REVERSE_C Control
14 ON_A3 I/O
15 OP_A3 I/O
17 ON_A2 I/O
18 OP_A2 I/O
19, 44 V
20 ON_A1 I/O
21 OP_A1 I/O
23 ON_A0 I/O
24 OP_A0 I/O

Power Negative supply

EE

Pre-emphasis control for Port A (LSB)
Pre-emphasis control for Port A (MSB)
Pre-emphasis control for Port B (LSB)
Pre-emphasis control for Port B (MSB)
Pre-emphasis control for Port C (LSB)
Pre-emphasis control for Port C (MSB)
Reverse inputs and outputs on Port C
High speed output complement
High speed output
High speed output complement
High speed output

Power Port A and Port B output termination supply

TTO

High speed output complement
High speed output
High speed output complement
High speed output

27 IN_A3 I/O High speed input complement

Rev. A | Page 5 of 24

AD8159

www.BDTIC.com/ADI

Pin No. Mnemonic Type Description

28 IP_A3 I/O High speed input
30 IN_A2 I/O High speed input complement
31 IP_A2 I/O High speed input
32, 57 V
33 IN_A1 I/O High speed input complement
34 IP_A1 I/O High speed input
36 IN_A0 I/O High speed input complement
37 IP_A0 I/O High speed input
39 ON_B3 I/O High speed output complement
40 OP_B3 I/O High speed output
42 ON_B2 I/O High speed output complement
43 OP_B2 I/O High speed output
45 ON_B1 I/O High speed output complement
46 OP_B1 I/O High speed output
48 ON_B0 I/O High speed output complement
49 OP_B0 I/O High speed output
52 IN_B3 I/O High speed input complement
53 IP_B3 I/O High speed input
55 IN_B2 I/O High speed input complement
56 IP_B2 I/O High speed input
58 IN_B1 I/O High speed input complement
59 IP_B1 I/O High speed input
61 IN_B0 I/O High speed input complement
62 IP_B0 I/O High speed input
64 BICAST Control Bicast enable
65 LB_A Control Loopback enable for Port A
66 LB_B Control Loopback enable for Port B
67 LB_C Control Loopback enable for Port C
68 SEL0 Control

69 SEL1 Control
70 SEL2 Control
71 SEL3 Control
72 EQ_C Control Equalization control for Port C

73 EQ_B Control Equalization control for Port B
74 EQ_A Control Equalization control for Port A
77 ION_C3 I/O High speed input/output complement
78 IOP_C3 I/O High speed input/output
80 ION_C2 I/O High speed input/output complement
81 IOP_C2 I/O High speed input/output
82 V
83 ION_C1 I/O High speed input/output complement
84 IOP_C1 I/O High speed input/output
86 ION_C0 I/O High speed input/output complement
87 IOP_C0 I/O High speed input/output
89 OIN_C3 I/O High speed output/input complement
90 OIP_C3 I/O High speed output/input
92 OIN_C2 I/O High speed output/input complement
93 OIP_C2 I/O High speed output/input
94 V
95 OIN_C1 I/O High speed output/input complement
96 OIP_C1 I/O High speed output/input
98 OIN_C0 I/O High speed output/input complement
99 OIP_C0 I/O High speed output/input

Power Port A and Port B input termination supply

TTI

/B select for Lane 0

A

/B select for Lane 1

A

/B select for Lane 2

A

/B select for Lane 3

A

Power Port C input/output termination supply

TTIO

Power Port C output/input termination supply

TTOI

Rev. A | Page 6 of 24

AD8159

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TYPICAL PERFORMANCE CHARACTERISTICS

VCC = +3.3 V, VEE = 0 V, RL = 50 Ω, basic configuration, data rate = 3.2 Gbps, input common-mode voltage = 2.7 V, differential input
swing = 800 mV p-p, T

Note: All graphs were generated using the setup shown in Figure 32, unless otherwise specified.

= 25°C, unless otherwise noted.

A

0

–2

–4

–6

–8

150mV/DIV

39.0625ps/DIV

Figure 3. Output Port A Eye Diagram 3.2 Gbps

Input Port A or Input Port C

150mV/DIV

39.0625ps/DIV

Figure 4. Output Port B Eye Diagram

Input Port B

or Input Port C

05611-003

05611-004

–10

–12

BIT ERROR RATE (Decades)

–14

–16

0 1.0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

TIME (Unit Interval)

Figure 6. Output Port A Bathtub Curve 3.2 Gbps

0

–2

–4

–6

–8

–10

–12

BIT ERROR RATE (Decades)

–14

–16

0 1.0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

TIME (Unit Interval)

Figure 7. Output Port B Bathtub Curve 3.2 Gbps

0

05611-006

05611-007

–2

–4

–6

–8

150mV/DIV

39.0625ps/DIV

Figure 5. Output Port C Eye Diagram 3.2 Gbps

Input Port A

or Input Port B

05611-005

–10

–12

BIT ERROR RATE (Decades)

–14

–16

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

01

Figure 8. Output Port C Bathtub Curve 3.2 Gbps

Rev. A | Page 7 of 24

TIME (Unit Interval)

05611-008

.0

AD8159

www.BDTIC.com/ADI

150mV/DIV

39.0625ps/DIV

Figure 9. Eye Diagram over Backplane

(18

” FR4 + 2 GbX Connectors), PE = 0

150mV/DIV

Figure 10. Eye Diagram over Backplane

(30

” FR4 + 2 GbX Connectors), PE = 0

39.0625ps/DIV

05611-009

05611-044

150mV/DIV

39.0625ps/DIV

Figure 12. Eye Diagram over Backplane

(18

” FR4 + 2 GbX Connectors), PE = 1

150mV/DIV

Figure 13. Eye Diagram over Backplane

(30” FR4 + 2 GbX Connectors), PE = 2

39.0625ps/DIV

05611-012

05611-013

150mV/DIV

39.0625ps/DIV

Figure 11. Eye Diagram over Backplane

(36

” FR4 + 2 GbX Connectors), PE = 0

05611-011

150mV/DIV

39.0625ps/DIV

Figure 14. Eye Diagram over Backplane

(36

” FR4 + 2 GbX Connectors), PE = 3

Rev. A | Page 8 of 24

05611-014

AD8159

www.BDTIC.com/ADI

150mV/DIV

39.0625ps/DIV

Figure 15. Eye Diagram over Backplane

(42

” FR4 + 2 GbX Connectors), PE = 0

150mV/DIV

Figure 16. Reference Eye Diagram for Figure 19

39.0625ps/DIV

150mV/DIV

05611-015

Figure 18. Eye Diagram over Backplane

(42

150mV/DIV

05611-005

Figure 19. Eye Diagram with Equalization

Note: See Figure 34 for Test Circuit Used

39.0625ps/DIV

” FR4 + 2 GbX Connectors), PE = 3

39.0625ps/DIV

(10

” FR4), EQ = 0

05611-018

05611-016

150mV/DIV

39.0625ps/DIV

Figure 17. Reference Eye Diagram for Figure 20. Eye Diagram with Equalization

Figure 34 for Test Circuit Used

Figure 20

05611-044

150mV/DIV

” FR4 + 2 GbX Connectors), EQ = 1

(34

Note: See

Rev. A | Page 9 of 24

39.0625ps/DIV

05611-019

AD8159

www.BDTIC.com/ADI

100

90

80

70

60

50

40

30

DETERMINISTIC JITTER (ps)

20

10

0

1.0 3.6

1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4

DATA RATE (Gbps)

Figure 21. Deterministic Jitter vs. Data Rate

100

VICM = 2.7V

90

80

70

60

INPUT C

50

40

30

DETERMINISTIC JITTER (ps)

INPUT A/B

20

10

0

0 2000

200 400 600 800 1000 1200 1400 1600 1800

DIFFERENTIAL INPUT SWING (mV p-p)

Figure 22. Deterministic Jitter v

s. Differential Input Swing

100

90

80

70

60

50

INPUT C

40

30

DETERMINISTIC JITTER (ps)

20

10

0

1.8 4.0

INPUT A/B

2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8

Figure 23. Deterministic Jitte

VCC (V)

r vs. Core Supply Voltage

05611-021

05611-024

05611-025

–2ps 0s–3ps 3ps

2ps–1ps 1ps

Figure 24. Random Jitter Histogram

Note: See

Figure 35 for Test Circuit Used

100

DIFFERENTIAL I NPUT SWI NG = 800mV p- p

90

80

INPUT A/B

70

60

50

40

30

DETERMINISTIC JITTER (ps)

20

10

0

04

0.5 1.0 1.5 2.0 2.5 3.0 3. 5

INPUT C

INPUT COMMON-MODE VOLTAGE (V)

Figure 25. Deterministic Jitter vs. Input Common-Mode Voltage

100

90

80

70

60

50

40

30

DETERMINISTIC JITTER (ps)

20

10

0

2.0 4.0

OUTPUT C

OUTPUT A/B

2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8

OUTPUT TERMINATION VOLTAGE (V)

Figure 26. Deterministic Jitter vs. Output Termination Voltage

05611-020

05611-023

.0

05611-026

Rev. A | Page 10 of 24

AD8159

www.BDTIC.com/ADI

100

90

80

70

60

50

40

30

DETERMINISTIC JITTER (ps)

20

10

0

–60 100

–40–200 20406080

TEMPERATURE (°C)

05611-022

Figure 27. Deterministic Jitter vs. Temperature

120

100

80

60

40

TRANSITION TIME (ps)

20

0

–60 100

–40–200 20406080

TEMPERATURE (°C)

Figure 28. Transition Time vs. Temperature

Note: See Figure 33 for Test Circuit Used

05611-027

Rev. A | Page 11 of 24

AD8159

www.BDTIC.com/ADI

EVALUATION BOARD SIMPLIFIED BLOCK DIAGRAMS

A

B

AD8159

AC-COUPLED

EVALUATIO N BOARD

C

AD8159-EVAL-AC

AC-COUPLED
EVALUATIO N BOARD

100Ω DIFF.
TRACE

0.1µF

100Ω DIFF.

C

A

B

TRACE

0.1µF

100Ω DIFF.
TRACE

0.1µF

5" 5"

INPUT A

INPUT B

INPUT C

V

TTI

V

TTIO

3.3V

/

VCCV

AD8159

V

EE

/

TTO

V

TTOI

OUTPUT C

OUTPUT A

OUTPUT B

100Ω DIFF.
TRACE

100Ω DIFF.
TRACE

100Ω DIFF.
TRACE

0.1µF

0.1µF

0.1µF

05611-028

Figure 29. AC-Coupled Evaluation Board Simplified Block Diagram

AD8159-EVAL-DC

DC-COUPLED
EVALUATIO N BOARD

/

A

B

AD8159

DC-COUPLED

EVALUATIO N BOARD

C

VCCV

V

TTI

V

TTIO

100Ω DIFF.
TRACE

100Ω DIFF.

C

A

B

TRACE

100Ω DIFF.
TRACE

5" 5"

INPUT A

INPUT B

INPUT C

AD8159

V

EE

–3.3V

Figure 30. DC-Coupled Evaluation Board Simplified Block Diagram

/

TTO

V

TTOI

OUTPUT C

OUTPUT A

OUTPUT B

100Ω DIFF.
TRACE

100Ω DIFF.
TRACE

100Ω DIFF.
TRACE

05611-029

Rev. A | Page 12 of 24

AD8159

T

www.BDTIC.com/ADI

TEST CIRCUITS

All graphs were generated using the setup shown in Figure 32, unless otherwise specified.

TERADYNE FR4 TEST BACKPLANE

GBX4 TO SMA DAUG HTER CARDS

0.25"

DIFFERENTIAL STRIPLINE TRACES
8mm WIDE, 8mm SPACE, 8mm HEIGHT

RACE LENGTHS = 6", 18", 24", 30" + 3" × 2 DAUGHTER CARDS

Figure 31. Test Backplane

05611-030

DATA OUT

PATTERN

GENERATOR

NOTES

1. SINGLE-ENDED REPRESENTATION

DATA OUT

PATTERN

GENERATOR

NOTES

1. SINGLE-ENDED REPRESENTATION

50Ω CABLE

50Ω CABLE

A

B

AD8159

AC-COUPLED

EVALUATIO N BOARD

C

A

B

AD8159

DC-COUPLED

EVALUATIO N BOARD

C

C

A

50Ω

B

50Ω

TEST BACKPLANE

Figure 32. AC-Coupled Test Circuit

C

A

B

50Ω CABLE

50Ω

50Ω

TEST BACKPLANE

Figure 33. DC-Coupled Test Circuit

No

te: Test Circuit Used for Figure 28

50Ω CABLE50Ω CABLE

50Ω CABLE

HIGH SPEED

REAL-TIME

OSCILLOSCOPE

50Ω

HIGH SPEED

REAL-TIME

OSCILLOSCOPE

50Ω

05611-031

05611-032

Rev. A | Page 13 of 24

AD8159

www.BDTIC.com/ADI

50Ω CABLE

DATA OUT

PATTERN

GENERATO R

NOTES

1. SINGLE-ENDED REPRESENTATION

A

B

C

C

AD8159

DC-COUPLED

EVALUATI ON BOARD

DATA OUT

PATTERN

GENERATOR

NOTES

1. SINGLE-ENDED REPRESENTATION

A

B

50Ω

No

te: Test Circuit Used for Figure 19 and Figure 20

50Ω CABLE

50Ω CABLE50Ω CABLE

TEST BACKP LANE

50Ω

Figure 34. Equalization Test Circuit

A

B

AD8159

AC-COUPLED

EVALUATIO N BOARD

C

50Ω CABLE

C

A

B

50Ω

Figure 35. Random Jitter Test Circuit

te: Test Circuit Used for Figure 24

No

DEVICE UNDER T EST

A

B

AD8159

DC-COUPLE D

EVALUATI ON BOARD

C

HIGH SPEED

SAMPLING

OSCILLOSCOPE

50Ω

50Ω

C

A

B

50Ω

50Ω CABLE

50Ω

05611-034

HIGH SPEED

REAL-TI ME

OSCILLOSCOPE

50Ω

05611-033

Rev. A | Page 14 of 24

AD8159

www.BDTIC.com/ADI

THEORY OF OPERATION

The AD8159 relays received data on the demultiplexer Input
Port C to Output Port A and/or Output Port B, depending on
the mode selected by the BICAST control pin. On the
multiplexer side, the AD8159 relays received data on either
Input Port A or Input Port B to Output Port C, based on the
SEL[3:0] pin states.

The AD8159 is configured by toggling control pins. On the demul-

iplexer side, when the device is configured in the unicast mode,

t
it sends the received data on Input Port C to Output Port A or
Output Port B. When the device is configured in the bicast mode,
received data on Input Port C is sent to both Output Port A and
Output Port B.

On the multiplexer side, only received data on Input Port A or
I

nput Port B is sent to Output Port C, depending on the state of
the SEL[3:0] pins. Tab l e 4 summarizes port selection and
c

onfiguration when loopback is disabled (LB_A = LB_B = LB_C

= 0).

When the device is in unicast mode, the output lanes on either
Po

rt A or Port B are in an idle state. In the idle state, the output
tail current is set to 0, and the P and N sides of the lane are
pulled up to the output termination voltage through the on-chip
termination resistors.

Table 4. Port Selection and Configuration Table

SEL BICAST OUT_A OUT_B OUT_C

0 0 IN_C Idle IN_A
0 1 IN_C IN_C IN_A
1 0 Idle IN_C IN_B
1 1 IN_C IN_C IN_B

Table 5. Port C I/O Selection

Port C when REVERSE_C = 0 Port C when REVERSE_C = 1 Port C Pin List on

100-Lead TQFP

77 ION_C3 = INN_C3 Input pin ION_C3 = OUTN_C3 Output pin
78 IOP_C3 = INP_C3 Input pin IOP_C3 = OUTP_C3 Output pin
80 ION_C2 = INN_C2 Input pin ION_C2 = OUTN_C2 Output pin
81 IOP_C2 = INP_C2 Input pin IOP_C2 = OUTP_C2 Output pin
83 ION_C1 = INN_C1 Input pin ION_C1 = OUTN_C1 Output pin
84 IOP_C1 = INP_C1 Input pin IOP_C1 = OUTP_C1 Output pin
86 ION_C0 = INN_C0 Input pin ION_C0 = OUTN_C0 Output pin
87 IOP_C0 = INP_C0 Input pin IOP_C0 = OUTP_C0 Output pin
89 OIN_C3 = OUTN_C3 Output pin OIN_C3 = INN_C3 Input pin
90 OIP_C3 = OUTP_C3 Output pin OIP_C3 = INP_C3 Input pin
92 OIN_C2 = OUTN_C2 Output pin OIN_C2 = INN_C2 Input pin
93 OIP_C2 = OUTP_C2 Output pin OIP_C2 = INP_C2 Input pin
95 OIN_C1 = OUTN_C1 Output pin OIN_C1 = INN_C1 Input pin
96 OIP_C1 = OUTP_C1 Output pin OIP_C1 = INP_C1 Input pin
98 OIN_C0 = OUTN_C0 Output pin OIN_C0 = INN_C0 Input pin
99 OIP_C0 = OUTP_C0 Output pin OIP_C0 = INP_C0 Input pin

Pin Name Input/Output Pin Name Input/Output

INPUT EQUALIZATION (EQ) AND OUTPUT PRE-EMPHASIS (PE)

In backplane applications, the AD8159 needs to compensate
for signal degradation over potentially long traces. The device
supports two levels of input equalization, configured on a per­port basis.
gain (EQ) for each control setting as
of backplane trace that can be compensated for each setting.

The AD8159 also has four levels of output pre-emphasis,
configured for each port. The pre-emphasis circuitry adds
a controlled amount of overshoot to the output waveform
to compensate for the loss in a backplane trace.

Tabl e 9 to Ta bl e 11 summarize the high-frequency gain, amount
o

f overshoot, and the typical backplane channel length (including
two connectors) that can be compensated using each setting. A
typical backplane is made of FR4 material with 8 mil wide trace
and 8 mil spacing loosely coupled differential traces. Each
backplane channel consists of two connectors. The total length
of the channel includes three inches of traces on each card.

Table 6 to Table 8 summarize the high-frequency

well as the typical length

Rev. A | Page 15 of 24

AD8159

K

www.BDTIC.com/ADI

Table 6. IN_C Port Input Equalization Settings Table 10. OUT_A Port Output Pre-Emphasis Settings

EQ_C EQ Typical Backplane Length

0 6 dB 0 to 20 inches
1 12 dB 20 to 40+ inches

Table 7. IN_A Port Input Equalization Settings

EQ_A EQ Typical Backplane Length

0 6 dB 0 to 20 inches
1 12 dB 20 to 40+ inches

Table 8. IN_B Port Input Equalization Settings

EQ_B EQ Typical Backplane Length

0 6 dB 0 to 20 inches
1 12 dB 20 to 40+ inches

Table 9. OUT_C Port Output Pre-Emphasis Settings

Typical

plane

Back

PE_C[1] PE_C[0] PE Overshoot

Length

0 0 0 dB 0% 0 to 10 inches
0 1 1.9 dB 15% 10 to 20 inches
1 0 3.5 dB 35% 20 to 30 inches
1 1 4.9 dB 60% 30 to 40+ inches

PE_A[1] PE_A[0] PE Overshoot

0 0 0 dB 0% 0 to 10 inches
0 1 1.9 dB 15% 10 to 20 inches
1 0 3.5 dB 35%
1 1 4.9 dB 60% 30 to 40+ inches

Table 11. OUT_B Port Output Pre-Emphasis Settings

PE_B[1] PE_B[0] PE Overshoot

0 0 0 dB 0% 0 to 10 inches
0 1 1.9 dB 15% 10 to 20 inches
1 0 3.5 dB 35%
1 1 4.9 dB 60% 30 to 40+ inches

LOOPBACK

The AD8159 also supports port level loopback, illustrated in
Figure 36. The loopback control pins override the lane select

EL[3:0]) and bicast control (BICAST) pins. Tab l e 1 2 summa-

(S
r

izes the different loopback configurations.

Typ ic al
Backplane
Length

20 to 30 inches

Typ ic al
Backplane
Length

20 to 30 inches

IN_C[3:0]

PORT C LOOPBAC

OUT_C[3:0]

X4

X4

X4

Figure 36. Port-Based Loopback Cap

1:2 DEMUX

X4

X4

2:1 MUX

X4

ability

OUT_A[3:0]

OUT_B[3:0]

PORT A LOOPBACK

PORT B LOOPBACK

IN_A[3:0]

IN_B[3:0]

05611-035

Rev. A | Page 16 of 24

AD8159

www.BDTIC.com/ADI

Table 12. Loopback, Bicast, and Port Select Settings

1

LB_A LB_B LB_C SEL BICAST OUT_A OUT_B OUT_C

0 0 0 0 0 IN_C Idle IN_A
0 0 0 0 1 IN_C IN_C IN_A
0 0 0 1 0 Idle IN_C
0 0 0 1 1 IN_C IN_C
0 0 1 0 0 IN_C Idle
0 0 1 X 1 IN_C IN_C
0 0 1 1 0 Idle IN_C
0 1 0 0 X IN_C IN_B
0 1 0 1 0 Idle IN_B
0 1 0 1 1 IN_C IN_B
0 1 1 0 X IN_C IN_B
0 1 1 1 0 Idle IN_B
0 1 1 X 1 IN_C IN_B
1 0 0 0 0 IN_A Idle
1 0 0 0 1 IN_A IN_C
1 0 0 1 X IN_A IN_C
1 0 1 0 0 IN_A Idle
1 0 1 X 1 IN_A IN_C
1 0 1 1 X IN_A IN_C
1 1 0 0 X IN_A IN_B
1 1 0 1 X IN_A IN_B

IN_B
IN_B
IN_C
IN_C
IN_C
IN_A
IN_B
IN_B
IN_C
IN_C
IN_C
IN_A
IN_A
IN_B
IN_C
IN_C
IN_C
IN_A
IN_B

1 1 1 X X IN_A IN_B IN_C

1

Switching is done on a lane-by-lane basis, but input equalization, output pre-emphasis, and loopback are set for each port.

PORT C REVERSE (CROSSOVER) CAPABILITY

Port C has a reversible I/O capability. The sense (input vs.
output) of the Port C pins can be swapped by toggling the
REVERSE_C control pin. This feature has been added to
facilitate the connection to different ASICs that may have
the opposite pinouts.

Figure 37 illustrates the reversible I/O function of Port C, and
Tabl e 5 describes this function in a selection table that
co

rresponds to a TQFP-100 package. Please note that the

reverse capability is supported only on Port C.

IN_C [3:0]/OUT_C[3:0]

OUT_C [3:0]/IN_C[3:0]

X4

X4

I/O

SWITCH

X4REVERSE_C

I/O

SWITCH

Figure 37. Port C Reverse I/O Capability

X4

X4

1:2 DEMUX

X4

X4

2:1 MUX

X4

OUT_A[3:0]

OUT_B[3:0]

IN_A[3:0]

IN_B[3:0]

05611-036

Rev. A | Page 17 of 24

AD8159

www.BDTIC.com/ADI

APPLICATIONS

The main application of the AD8159 is to support redundancy
on both the backplane side and the line interface side of a serial
link. Each port consists of four lanes to support standards such
as XAUI.
sys

tem. Each line card is connected to two switch fabrics
(primary and redundant). The device can be configured to
support either 1 + 1 or 1:1 redundancy.

Another application for the AD8159 is test equipment for
eval

uating high speed serial I/Os running at data rates at or
lower than 3.2 Gbps. Figure 40 illustrates a possible application
o

f the AD8159 in a simple XAUI link tester.Figure 38 illustrates redundancy in an XAUI backplane

PHYSICAL

INTERFACE

PHYSICAL

INTERFACE

MACs

FRAMERS

MACs

FRAMERS

FABRIC INTERFACE

TRAFFIC MANAGERS

NETWORK PROCESSOR

FABRIC INTERFACE

TRAFFIC MANAGERS

NETWORK PROCESSOR

AD8159

LINE CARDS

AD8159

Figure 38. Using the AD8159 for Switch Redundancy

PRIMARY

MODULE

MACs

FRAMERS

REDUNDANT

MODULE

Figure 39. Using the AD8159 for Line Interface Redundancy

CONNECT TO DEVICE UNDER TEST

BACKPLANE

FABRIC INTERFACE

TRAFFIC MANAGERS

NETWORK PROCESSOR

LINE CARD

PRIMARY

SWITCH
FABRIC

REDUNDANT

SWITCH
FABRIC

FABRIC CARDS

05611-038

05611-037

CONNECTOR

PORT B

CONNECT TO PROTOCOL

ANALYZER

CONNECTOR

PORT A

PORT C

FPGA

GENERATES SIMPLE

PATTERNS

TEST CARD

05611-039

Figure 40. Using the AD8159 in Test Equipment

Rev. A | Page 18 of 24

AD8159

V

V

V

www.BDTIC.com/ADI

INTERFACING TO THE AD8159

TERMINATION STRUCTURES

To determine the best strategy for connecting to the high speed

ins of the AD8159, the user must first be familiar with the on-

p
chip termination structures. The AD8159 contains two types of
these structures (see
and bidirectional ports and one type for output ports.

Figure 41. Termination Structure: Input and Bidirectional Ports

Figure 41 and Figure 42): one type for input

TTI/VTTIO/VTTOI

54.5Ω 54.5Ω

1173Ω

NP

05611-040

TTO

For output ports, there are two 50 Ω resistors connected to the
termination supply. Note that the differential input resistance
for both structures is the same, 100 Ω.

INPUT COMPLIANCE

The range of allowable input voltages is determined by the

damental limitations of the active input circuitry. This range

fun
of signals is normally a function of the common-mode level of
the input signal, the signal swing, and the supply voltage. For a
given input signal swing, there is a range of common-mode
voltages that keeps the high and low voltage excursions within
acceptable limits. Similarly, for a given common-mode input
voltage there is a maximum acceptable input signal swing.
There is also a minimum signal swing that the active input
circuitry can resolve reliably.

50Ω

PN

Figure 42. Output Ports

50Ω

05611-041

For input and bidirectional ports, the termination structure
consists of two 54.5 Ω resistors connected to a termination
supply and an 1173 Ω resistor connected across the differential
inputs, the latter being a result of the finite differential input
impedance of the equalizer.

CC

50Ω 50Ω

C

P

C

N

IP

1173Ω

IN

AD8159

Figure 22 and Figure 25 summarize the input voltage ranges for
all ports. Note that the input range is different when comparing
bidirectional ports to strictly input ports. This is a consequence
of the additional circuitry required to support the bidirectional
feature on Port C.

AC Coupling

One way to simplify the input circuit and make it compatible
with a wide variety of driving devices is to use ac coupling. This
has the effect of isolating the dc common-mode levels of the
driver and the AD8159 input circuitry. AC coupling requires a
capacitor in series with each single-ended input signal, as shown
in

Figure 43. This should be done in a manner that does not

in

terfere with the high speed signal integrity of the PCB.

V

TTI/VTTIO

54.5Ω

54.5Ω

V

VEE

CC

DRIVER

Figure 43. AC-Coupling Input Signal of AD8159

Rev. A | Page 19 of 24

05611-042

AD8159

V

www.BDTIC.com/ADI

When ac coupling is used, the common-mode level at the input
of the device is equal to V
swings above and below V

. The single-ended input signal

TTI

equally. The user can then use

TTI

Figure 22 and Figure 25 to determine the acceptable range of
c

ommon-mode levels and signal swing levels that satisfy the

input range of the AD8159.

If dc coupling is required, determining the input common­m

ode level is less straightforward because the configuration of
the driver must be also be considered. In most cases, the user
would set V
output termination voltage, V

on the AD8159 to the same level as the driver

TTI

. This prevents a continuous

TTOD

dc current from flowing between the two supply nets. As a
practical matter, both devices can be terminated to the same
physical supply net.

Consider the following example: A driver is dc-coupled to the
in

put of the AD8159. The AD8159 input termination voltage
(V

) and the driver output termination voltage (V

TTI

set to the same level; that is, V

TTI

= V

TTOD

= 3.3 V. If an 800 mV

) are both

TTOD

differential p-p swing is desired, the total output current of the
driver is 16 mA. At balance, the output current is divided evenly
between the two sides of the differential signal path, 8 mA to each
side. This 8 mA of current flows through the parallel combina­tion of the 54.5 Ω input termination resistor on the AD8159
and the 50 Ω output termination resistor on the driver, resulting
in a common-mode level of

DC Coupling

First, consider the dc-coupled case (see Figure 44). A lane on

utput Port A or Output Port B on the AD8159 is dc-coupled

O
to a receiving device. In this example, the output termination
voltage (V
input termination voltage (V
this level sets the high value (V

) on the AD8159 is set to the same level as the

TTO

) on the receiving device, and

TTIR

) of the single-ended output

HI

voltage. With pre-emphasis low (PE = 0), the maximum single­ended current is 16 mA

1

, which flows through the parallel
combination of the 50  on-chip resistor and the 50 Ω far end
termination. Therefore, the low value (V

) of the output

LO

voltage is equal to

V

− 16 mA × (50 Ω || 50 Ω) = V

TTO

− 400 mV

TTO

Because the minimum allowed voltage at the output is

− 1.6 V, the lowest acceptable value for V

V

CC

V

− 1.6 V + 0.4 V = VCC − 1.2 V

CC

TTO

is

Increasing pre-emphasis to its highest level (PE = 3) results in

imum, single-ended current of 28 mA. In this case

a max

= V

V

LO

− 28 mA × (50 Ω || 50 Ω) = V

TTO

As a result, the lowest acceptable value for V

− 1.6 V + 0.7 V = VCC − 0.9 V

V

CC

2

− 700 mV

TTO

is

TTO

− 8 mA × (50 Ω || 54.5 Ω) = V

V

TTI

− 209 mV

TTI

The user can then use Figure 25 to determine the allowable
ra

nge of values for V

that meets the input compliance range

TTI

based on an 800 mV p-p differential swing.

OUTPUT COMPLIANCE

Not surprisingly, there is also a range of voltages that satisfies
the requirements of the output devices. This range is specified
as the minimum and maximum voltage (with respect to V
allowed at an output pin.

TTO

50Ω 50Ω

PORT A/B: ( 16 + 4 × PE) mA
PORT C: (20 + 4 × PE) mA

V

EE

Figure 44. DC-Coupling Output Signal from AD8159

)

CC

AD8159

OP

ON

It is expected that the minimum V

is 300 mV higher than the

TTO

case when PE = 0, because increasing the pre-emphasis level
results in a 300 mV lower voltage excursion at the output.

1

The output current for Port C when PE_C = 0 is slightly higher, 20 mA. The

extra 4 mA of current (compared to Port A/Port B) is needed to support the
bidirectional feature.

2

The output current for Port C when PE_C = 3 is 32 mA, for the same reason

as stated in Endnote 1.

V

TTIR

RECEIVING DE VICE

05611-043

Rev. A | Page 20 of 24

AD8159

www.BDTIC.com/ADI

AC Coupling

In general, more V

supply headroom is required with ac-

TTO

coupled outputs. When the outputs are ac-coupled, the average
single-ended current does not see the far end 50 Ω termination
because the capacitor acts as a dc block. For example, with
PE = 0, the single-ended output current alternates from 0 mA
to 16 mA, or 8 mA on average. This 8 mA current flows entirely
through the on-chip 50 Ω termination resistor due to the dc
block.

The single-ended output voltage has an average value of

V

− 8 mA × 50 Ω = V

TTO

For appropriate data patterns,

− 400 mV

TTO

1

the capacitor acts as a short and
the voltage swing is 400 mV p-p, identical to the dc-coupled case.
The low output voltage is, therefore,

− 400 mV − 200 mV = V

V

TTO

− 600 mV

TTO

1

AC coupling requires that the signal pattern have no long term dc

component. Codes such as 8b/10b, for example, ensure that the data
pattern is benign in an ac-coupled link.

The lowest acceptable value for V

V

− 1.6 V + 0.6 V = VCC − 1.0 V

CC

TTO

is

The same exercise can be repeated for other pre-emphasis

ttings.

se

Output Compliance Table

To simplify the task of interfacing to the AD8159 output,
Tabl e 13 is useful as a quick-reference. It provides the minimum

nd maximum values for output termination voltage for both

a
ac and dc coupling. The values in the table are valid for any pre­emphasis setting.

Table 13. Output Compliance

AC-Coupled DC-Coupled

V

TTO VCC

V

TTOI VCC

Minimum
(V)

– 0.5 VCC + 0.6 VCC – 0.9 VCC + 0.6
– 0.4 VCC + 0.6 VCC – 0.8 VCC + 0.6

Maximum
(V)

Minimum
(V)

Maximum
(V)

Rev. A | Page 21 of 24

AD8159

www.BDTIC.com/ADI

OUTLINE DIMENSIONS

1.05

1.00

0.95

0.15

SEATING

0.05

PLANE

VIEW A

ROTATED 90° CCW

1.20

0.75
MAX

0.60

0.45

0° MIN

0.20

0.09
7°

3.5°
0°

0.08 MAX
COPLANARIT Y

NOTES

1. CENTER FI GURES ARE TYPICAL UNL ESS OTHERWI SE NOTED.

2. THE AD8159 HAS A CONDUCTIVE HEAT SLUG TO HELP DISS IPATE HEAT AND ENSURE RELIABLE OPERATION OF
THE DEVICE O VER THE FULL INDUSTRIAL T EMPERATURE RANGE. THE SLUG IS EXPOSED ON T HE BOTTOM OF
THE PACKAGE AND ELECTRICALLY CONNECTED TO V
TRACES OR VIAS BE LOCATED UNDER THE PACKAGE THAT COULD COME IN CONTACT WITH THE CONDUCT IVE
SLUG. ATTACHING THE SLUG TO A V

DEVICE WHICH MAY BE BENEFICIAL IN HIG H TEMPERATURE ENVIRONME NTS.

Figure 45. 100-Lead Thin Quad Flat Packag

16.00 BSC SQ

1

PIN 1

25

26 50

VIEW A

COMPLIANT TO JEDEC STANDARDS MS-026-AED-HD

PLANE WILL REDUCE T HE JUNCTION T EMPERATURE OF THE

EE

14.00 BSC SQ

TOP VIEW

(PINS DOWN)

76100

. IT IS RECOMMENDED THAT NO PCB SIG NAL

EE

76 100

75

75

51

51

e, Exposed Pad [TQFP_EP]

EXPOSED

BOTTOM VIEW

0.50 BSC

LEAD PITCH

PAD

(PINS UP)

0.27

0.22

0.17

2650

(SV-100-4)

Dimensions shown in millimeters

1

5.00 SQ

25

040506-A

ORDERING GUIDE

Model Temperature Range Package Description Package Option

AD8159ASVZ −40°C to +85°C 100-Lead TQFP_EP SV-100-4
AD8159-EVAL-DC −40°C to +85°C DC-Coupled Evaluation Board
AD8159-EVAL-AC −40°C to +85°C AC-

1

Z = Pb-free part.

1

Coupled Evaluation Board

Rev. A | Page 22 of 24

AD8159

www.BDTIC.com/ADI

NOTES

Rev. A | Page 23 of 24

AD8159

www.BDTIC.com/ADI

NOTES

©2006 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.

D05611-0-4/06(A)

Rev. A | Page 24 of 24