MAXIM MAX3891 User Manual

General Description

The MAX3891 evaluation kit (EV kit) is an assembled
surface-mount demonstration board that provides easy
evaluation of the MAX3891 2.5Gbps, 16:1 serializer with
clock synthesis and single-ended, low-voltage PECL
inputs.

The MAX3891 EV kit is optimized for +3.3V operation.
Total current consumption at 3.3V is 570mA. The EV kit
provides PECL terminations and controlled 50Ω imped-
ances on all input and output data lines.

Features

♦ +3.3V Single Supply

♦ Selectable Reference Clock Frequencies

(155.52MHz, 51.84MHz, 77.76MHz, 38.88MHz)

♦ Fully Assembled and Tested Surface-Mount

Board

Evaluates: MAX3891

MAX3891 Evaluation Kit

________________________________________________________________ Maxim Integrated Products 1

19-1969; Rev 0; 2/01

Component List

Ordering Information

Component Suppliers

Note: Please indicate you are using the MAX3891 when con­tacting the suppliers.

*Exposed pad

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

DESIGNATION QTY DESCRIPTION

C1–C6, C8–C11,

C13–C32,

C34–C37

C7 1

C12 1

J1–J6 6 SMA connectors (side mount)

J7–J24, J27, J28 20 SMB connectors (PC mount)

J25, J26 2 SMA connectors (PC mount)

JU1, JU3–JU9 8 2-pin headers (0.1in centers)

L1–L5 5

R1, R2 2 49.9Ω ±1% resistors (0402)

R3 1 10kΩ ±1% resistor (0402)

R4, R8, R12, R16,

R28, R29

R5, R9, R13, R17,

R24, R25

R6, R10, R14, R18,

R89, R93

0.1µF ±10%, 10V min ceramic

34

capacitors (0603)

0.33µF ±10%, 25V min ceramic
capacitor (0603)

33µF ±10%, 10V min tantalum
capacitor
Sprague 293D336X0010C2

56nH inductors
Coilcraft 0805CS-560XKBC

6 27.4Ω ±1% resistors (0402)

6 24.3Ω ±1% resistors (0402)

6 221Ω ±1% resistors (0402)

PART TEMP. RANGE IC PACKAGE

MAX3891EVKIT -40°C to +85°C 64 TQFP-EP*

DESIGNATION QTY DESCRIPTION

R7, R11, R15,
R19, R20, R26,
R30, R32, R33,
R34, R36, R38,
R42, R46, R50,
R54, R58, R62,
R66, R70, R74,
R78, R81, R85,

R91, R95

R21, R27, R31,

R35, R37, R39,
R40, R41, R43,
R47, R51, R55,
R59, R63, R67,
R71, R75, R79,

R83, R87

R22, R23 2 20kΩ ±1% resistors (0402)

U1 1 MAX3891ECB (64-pin TQFP-EP)

VCC, GND 2 Test points

None 8 Shunts

None 1 MAX3891 EV kit circuit board

None 1 MAX3891 data sheet

SUPPLIER PHONE FAX

Coilcraft 847-639-6400 847-639-1469

Sprague 207-324-4140 603-224-1430

26 130Ω ±1% resistors (0402)

20 82.5Ω ±1% resistors (0402)

Evaluates: MAX3891

MAX3891 Evaluation Kit

2 _______________________________________________________________________________________

Detailed Description

The MAX3891 EV kit contains all components needed
to simplify the evaluation of the MAX3891 16:1 serializ­er. The completely assembled and factory-tested EV kit
operates from a single +3.3V supply and includes all
external components necessary to interface with stan­dard 50Ω test equipment. On-board termination and
AC coupling is provided for the MAX3891’s single­ended LV PECL parallel data inputs. The differential LV
PECL serial data outputs are also terminated on-board
with resistive networks optimized for forward and
reverse 50Ω termination. The evaluation kit also pro­vides AC coupling and 50Ω terminations for the CML
system loopback outputs. Control functions and operat­ing parameters are programmed with jumpers. The ref­erence clock rate is programmed with JU3–JU5, the
PLL loop filter capacitor can be shorted by shorting
JU6, and the system loopback outputs can be selected
for diagnostic testing by setting JU1 appropriately.

Layout Considerations

All differential signal outputs are of equal length and
use coupled 50Ω transmission lines so that propagation
delay skew is minimized. The on-board impedance
matching resistive networks provided for the PECL out­puts allow easy interface of the EV kit to standard test
equipment with 50Ω terminations to ground. These min­imum loss pads are optimized for both forward and
reverse 50Ω impedance and attenuate the MAX3891’s
output signal by 0.46V/V (6dB). SMA connectors are
provided for all high-speed differential outputs (SDI±,
SLBI±, and SCLKO±) and for the differential reference
clock input (RCLK±). SMB connectors are provided for
the single-ended input data signals (PDI_) parallel input
clock (PCLKI±) and parallel output clock (PCLKO±)

Supply power is routed to the MAX3891 through five
separate, independently filtered voltage supplies:
VCCDIG, VCCO, VCCPLL, VCCVCO, and VCCPECL.

Care must be taken when designing power-supply fil­tering as the VCCVCO supply is most susceptible to
power-supply noise. Noise on the VCO supply causes
the VCO to generate phase noise, which could degrade
the MAX3891’s jitter performance. Inductive filtering is
recommended for the VCO supply. Noise on the VCCO
supply is effectively rejected; however, because of the
external PECL biasing, significant noise is coupled
back onto the VCCO supply pin. Ideally, this supply
should be isolated from all the others. At the least, iso­late the VCCO supply from the VCCVCO supply. The
single-ended PECL inputs could be affected by noise
on the VCCPECL supply. Since PECL signal swings are
much larger than the expected supply noise, the PECL
inputs require relatively simple filtering. Decoupling
capacitors placed close to the IC should be adequate
in most cases. The VCCPLL and VCCDIG supplies
power the rest of the IC. These supplies have moderate
supply noise rejection and contribute moderately to
total supply-induced noise. In most cases, VCCPLL and
VCCDIG can also be decoupled with capacitors placed
close to the IC.

Jumpers and Test Points

The MAX3891 EV kit provides jumpers to allow easy
configuration of the MAX3891’s mode of operation.
Table 1 gives a brief description of the MAX3891’s
jumper functions. The SOS jumper, JU1, configures the
data output path. For normal operation, short pins 1
and 2 of JU1 to disable the SLBO outputs. For system
loopback diagnostic testing, remove the shunt from
JU1 to enable the system loopback outputs.

The MAX3891 has the ability to use multiple reference
clock frequencies. Use the CLKSET jumpers JU2, JU3,
and JU4 to program the MAX3891’s reference clock
input for 38.88MHz, 51.84MHz, 77.76MHz, or

155.52MHz (Table 2). For example, remove the shunts
from JU3 and JU5 and short pins 1 and 2 of JU4 for
operation using a 51.84MHz reference clock.

Table 1. Jumpers, Test Points,
and Connections

Table 2. CLKSET Jumper Functions

NAME TYPE DESCRIPTION

JU1

JU3,

JU4, JU5

JU6

Two-pin

header

Two-pin

header

Two-pin

header

U sed to enab l e/d i sab l e
the S LBO outp uts.

Used to program the
reference clock
frequency

Used to short the filter
(FIL ±) pins

NORMAL

POSITION

Shorted

See Table 2

Open

f

RCLK

(MHz)

155.52 Shorted (to VCC) Open Open

77.76 Open Open Open

51.84 Open

38.88 Open Open

JU3 JU4 JU5

S hor ted
( 20kΩ to g r ound )

Open

Shorted
(to ground)

Quick Start

The MAX3891 allows the use of multiple reference
clock frequencies. Be sure to set the clockset jumpers
appropriately for your reference clock frequency. The
following procedure sets up the EV kit for a 155.52MHz
reference clock.

1) Verify that the shunts are in place on 2-pin headers
JU1 and JU3. JU1 will disable the SLBO outputs
and JU3 will select the input reference clock fre­quency of 155.52MHz.

2) Verify that the shunts are removed from 2-pin head­ers JU4, JU5, and JU6.

3) Connect the differential output of your reference
clock through 50Ω cables to the differential RCLK±
inputs.

4) Connect your single-ended signal source outputs
through 50Ω cables to the parallel data (PDI_)
inputs. If 16 separate 155.52MHz signal generators
are not available, tie the unused parallel data inputs
to either a PECL high or PECL low. To tie an input to
a PECL high, remove the 130Ω PECL biasing resis­tor. To tie an input to a PECL low, reverse positions
of the PECL input biasing resistors.

5) Connect the differential parallel input clock through
50Ω cables to the PCLKI± inputs.

6) Connect the serial data and clock outputs through
50Ω cables to a 50Ω oscilloscope (minimum 3GHz
bandwidth) or test equipment.

7) Power up the EV kit with a 3.3V supply and check
the signal at the output.

Exposed Pad Package

The exposed pad (EP) 64-pin TQFP incorporates fea­tures that provide a very low thermal-resistance path for
heat removal from the IC—either to a PC board or to an
external heat sink. The MAX3891’s EP must be sol­dered directly to a ground plane with good thermal
conductance.

Evaluates: MAX3891

MAX3891 Evaluation Kit

_______________________________________________________________________________________ 3

Evaluates: MAX3891

MAX3891 Evaluation Kit

4 _______________________________________________________________________________________

Figure1. MAX3891 EV Kit Schematic

3R3V

VCC

J46

C12

33µF

GND

J47

VCC

C1

R4

27.4Ω

R8

27.4Ω

R12

27.4Ω

R16

27.4Ω

0.1µF

C32

0.1µF

0.1µF

C2

0.1µF

C6

24.3Ω

R6
221Ω

24.3Ω

R10
221Ω

24.3Ω

R14
221Ω

24.3Ω

R18
221Ω

R32
130Ω

R5

R9

R13

R17

J1

SMA

J2

J2

SMA

SMA

J3

SMA

J4

SMA

J5

SMA

J6

SMA

J7

SMB

J8

SMB

C13

0.1µF

VCC

VCC

R1

49.9Ω

R2

49.9Ω

R40

82.5Ω

R33
130Ω

VCC

56nH

56nH

56nH

56nH

56nH

C15

0.1µF

R7
130Ω

VCC

R11
130Ω

VCC

R15
130Ω

VCC

R19
130Ω

VCC

R41

82.5Ω

L1

VCCDIG

L2

VCC0

L3

VCCPLL

L4

VCCVCO

L5

VCCPECL

GND

VCC

R3
10kΩ

JU1

VCCO

C3

0.1µF

C10

0.1µF

VCCO

VCCO

VCCDIG

C35

0.1µF

R27

82.5Ω

R26

130Ω

C16

0.1µF

VCCPLL

VCCO

VCCO

0.1µF

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15
16

VCCPECL

VCC

R22

20kΩ

C9

VCCVCO

C11

0.1µF

GND
V

CC

SLBO­SLBO+
V

CC

SOS
V

CC

SCLKO­SCLKO+

V

CC

SDO­SDO+

V

CC

V

CC

PLKI+
PLKI-

R31

82.5Ω

R30

130Ω

C17

0.1µF

VCCDIG

JU6

64

CC

V

GND

17

18

63

GND

PDI15

VCC

JU3

JU4

JU5

C7

0.33µF

62

FIL-

FIL+

VCCPDI14

19

20

0.1µF

C8

0.1µF

61

21

R35

82.5Ω

R34

130Ω

C18

VCCPLL

60

CC

V

CLKSET

CC

V

PDI13

22

VCC

VCC

58

59

RCLK-

RCLK+

U1

MAX3891

VCCPDI12

23

24

82.5Ω

130Ω

0.1µF

C19

R38

57

R39

0.1µF

R37

82.5Ω

VCCDIGV

56

CC

CC

V

J26
SMA

C5

55

PCLKO-

PDI11

26

VCC

R36

130Ω

VCC

VCCPECL

54

V

PCLKO+

VCCPDI10

272528

82.5Ω

130Ω

0.1µF

53

CC

29

R43

R42

C20

C4

0.1µF

R21

82.5Ω

VCCPECL

52

CC

V

PDI0

CC

V

30

VCC

51

J25

SMA

31

PDI1

0.1µF

R20

130Ω

50

GND

VCCVCCPDI9

32

R47

82.5Ω

R46

130Ω

C21

49

GND

PDI2

PDI3

PDI4

PDI5

PDI6

PDI7

PDI8
GND

VCC

V

CC

V

CC

V

CC

V

CC

V

CC

V

CC

V

CC

VCCPECL

VCC

J28

SMB

R29

27.4Ω
R93

221Ω

R25

24.3Ω

R95

130Ω

VCCDIG

GNDTEST

R23

JU7

20kΩ

JU8

48

JU9

VCCDIG

C34

0.1µF

VCC

VCCPECL

C36VCCPECL

C14

0.1µF

C37

0.1µF

0.1µF

47
46
45
44
43
42
41

40
39
38
37
36
35
34
33

R51

82.5Ω

R50

130Ω

C22

0.1µF

SMB

J9

J10

SMB

J11

SMB

J12

SMB

J13

SMB

J14

SMB

J15

SMB

Evaluates: MAX3891

MAX3891 Evaluation Kit

_______________________________________________________________________________________ 5

Figure1. MAX3891 EV Kit Schematic (continued)

VCC

R28

27.4Ω

R24

24.3Ω
R91

130Ω

J27
SMB

R89

221Ω

VCC

C31

0.1µF

R87

82.5Ω

J24
SMB

R85

130Ω

VCC

C30

0.1µF

R83

82.5Ω

J23
SMB

R81
130Ω

VCC

VCC

VCC

VCC

VCC

VCC

VCC

R79

82.5Ω

R75

82.5Ω

R71

82.5Ω

R67

82.5Ω

R63

82.5Ω

R59

82.5Ω

R55

82.5Ω

R78

130Ω

R74

130Ω

R70

130Ω

R66

130Ω

R62

130Ω

R58

130Ω

R54

130Ω

C29

0.1µF

C28

0.1µF

C27

0.1µF

C26

0.1µF

C25

0.1µF

C24

0.1µF

C23

0.1µF

J22
SMB

J21
SMB

J20
SMB

J19
SMB

J18
SMB

J17
SMB

J16
SMB

Evaluates: MAX3891

MAX3891 Evaluation Kit

6 _______________________________________________________________________________________

Figure 2. MAX3891 EV Kit Component Placement Guide

1.0"

Evaluates: MAX3891

MAX3891 Evaluation Kit

_______________________________________________________________________________________ 7

Figure 3. MAX3891 EV Kit PC Board Layout —Component Side

1.0"

Evaluates: MAX3891

MAX3891 Evaluation Kit

8 _______________________________________________________________________________________

Figure 4. MAX3891 EV Kit PC Board Layout—Ground Plane

1.0"

Evaluates: MAX3891

MAX3891 Evaluation Kit

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9

© 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

Figure 5. MAX3891 EV Kit PC Board Layout—Power Plane

1.0"