MAXIM MAX3784, MAX3784A Technical data

General Description

The MAX3784/MAX3784A 5Gbps equalizers provide
compensation for transmission-medium losses in up to
40in of FR-4. They are optimized for short-run length
and balanced codes such as 8b10b, as found in multi­plexed 1.25Gbps Ethernet systems and 4.25Gbps
Fibre Channel.

The equalizers use differential CML data inputs and
outputs. A standby mode reduces power consumption
when the parts are not in use. The MAX3784/
MAX3784A are available in a 4mm × 4mm, 16-pin QFN
package that consumes only 185mW at +3.3V.

Features

♦ Spans 40in (1m) of FR-4 PCB

♦ 0.18UI Deterministic Jitter Up to 40in

♦ Low Power Consumption: 185mW (MAX3784)

♦ Equalization Reduces Intersymbol Interference

♦ Single +3.3V Supply

♦ Standby Mode

♦ Small 4mm × 4mm, 16-Pin QFN Package

MAX3784/MAX3784A

5Gbps PCB Equalizer

________________________________________________________________

Maxim Integrated Products

1

Pin Configurations

LINE CARD

+3.3V

5Gbps

+3.3V

T/R 1

Rx

Tx

T/R 2

Rx

Tx

T/R 3

Rx

Tx

T/R 4

Rx

Tx

T/R 1

T/R 2

T/R 3

T/R 4

Rx

Tx

1.25Gbps

1.25Gbps

1.25Gbps

1.25Gbps

SWITCH

Rx

Tx

SWITCH CARD

PCB

BACKPLANE

MAX3784/

MAX3784A

EQUALIZER

IN OUT

MAX3784/

MAX3784A

EQUALIZER

OUT IN

Typical Application Circuit

19-2565; Rev 4; 10/07

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

Ordering Information

Applications

Chassis Life Extension

4.25Gbps Fibre Channel

4x Multiplexed 1.25Gbps Ethernet (5Gbps)

+

Denotes a lead-free package.

*Exposed pad.

1

23

4

5

6

7

8

9

10

11

16

12

13

14

15

V

CC

V

CC

V

CC

IN+

IN-

GND

GND

GND

N.C.

N.C.

N.C.

N.C.

N.C.

EN

OUT+

OUT-

* THE EXPOSED PAD MUST BE SOLDERED TO SUPPLY GROUND
FOR CORRECT THERMAL AND ELECTRICAL PERFORMANCE.

MAX3784/

MAX3784A

TOP VIEW

QFN

*EP

Pin Configurations continued at end of data sheet.

PART

TEMP

RANGE

MAX3784UGE 0°C to +85°C 16 QFN-EP* G1644-1

MAX3784UTE+ 0°C to +85°C 16 TQFN-EP* T1644-3

MAX3 784AUGE 0°C to +85°C 16 QFN-EP* G1644-1

MAX3784AUTE+ 0°C to +85°C 16 TQFN-EP* T1644-3

PIN­PACKAGE

PKG

CODE

MAX3784/MAX3784A

5Gbps PCB Equalizer

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3V to +3.6V, TA= 0°C to +85°C. Typical values are at VCC= +3.3V and TA= +25°C, unless otherwise noted.)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

Supply Voltage, VCC.................................................-0.5V to +6V

Input Voltage............................................(-0.5V) to (V

CC

+ 0.5V)

Continuous Output Current ...............................-25mA to +25mA

Continuous Power Dissipation (T

A

= +85°C)

16-Pin QFN (derate 25mW/°C above +85°C) ............1600mW

Operating Ambient Temperature Range ................0°C to +85°C

Storage Temperature Range .............................-55°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

Supply Power

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

EN = low 30

EN = high 185 250

Latency From input to output 200 ps

CML RECEIVER INPUT

Input Voltage Swing V

Return Loss 100MHz to 2.5GHz 15 dB

Input Resistance Differential 80 100 120 Ω

EQUALIZATION

Residual Deterministic Jitter,
5Gbps

Residual Deterministic Jitter,

2.5Gbps

Residual Deterministic Jitter,

1.25Gbps

Random Jitter (Notes 5, 6) 1.3 1.9 ps

CML TRANSMITTER OUTPUT (into 100Ω ±1Ω)

Output Voltage Swing V

Transition Time t

Output Resistance Single ended 40 50 60 Ω

f, tr

Measured differentially at point A in Figure 1 400 1000 mV

IN

Table 1 (Notes 2–5)

Table 1 (Notes 2–5)

Table 1 (Notes 2–5)

Differential swing, measured

O

differentially at point C in Figure 1

20% to 80% (Notes 5, 8) 30 45 60 ps

10Hz < f < 100Hz 100

100Hz < f < 1MHz 40Supply-Noise Tolerance (Note 1)

1MHz < f < 2.5GHz 10

20in 0.13 0.21

40in 0.18 0.23

20in 0.08 0.14

40in 0.13 0.28

20in 0.04 0.07

40in 0.07 0.15

MAX3784 400 600

MAX3784A 550 750

mV

UI

UI

UI

mV

mW

P-P

P-P

P-P

P-P

P-P

RMS

P-P

MAX3784/MAX3784A

5Gbps PCB Equalizer

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3V to +3.6V, TA= 0°C to +85°C. Typical values are at VCC= +3.3V and TA= +25°C, unless otherwise noted.)

Note 1: Allowed supply noise during jitter tests.
Note 2: Test pattern. This is a combination of K28.5± characters running at the full bit rate and at one-quarter the bit rate. This simu-

lates the multiplexing of four each 1.25Gbps Ethernet data streams.
Pattern (hex) 100 bits
00 FFFF F0F0 FF 0000 0F0F (quarter rate K28.5+, quarter rate K28.5-)

3EB05 (K28.5± 00 1111 1010 11 0000 0101)

Note 3: Difference in deterministic jitter between reference points A and C in Figure 1.
Note 4: Signal source amplitude range is 400mV

P-P

to 1000mV

P-P

differential. Signal is applied differentially at point A as shown in
Figure 1. The deterministic jitter at point B must be from media-induced loss and not from clock-source modulation.
Deterministic jitter is measured at the 50% vertical level of the signal at point C.

Note 5: Guaranteed by design and characterization.
Note 6: Test pattern is K28.5 with 40in trace.
Note 7: On-chip pullup resistor of 40kΩ (typ). Negative current indicates equalizer sources current.
Note 8: Using 00 0001 1111 or equivalent pattern. Measured over entire input voltage range, max and min media loss and within 2in

of output pins.

Figure 1. Test Conditions

Table 1. PCB Assumptions (PCB material is FR-4)

ENABLE CONTROL PIN

Input High Voltage 1.5 V

Input Low Voltage 0.5 V

Input High Current (Note 7) -150 +10 µA

Input Low Current (Note 7) -150 +10 µA

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SIGNAL

SOURCE

A

SMA CONNECTOR

BACKPLANE PCB

6mil LINE

L ≤ 40in

SMA CONNECTOR

BC

MAX3784/MAX3784A

EQUALIZER

IN OUT

PARAMETER CONDITIONS MIN TY P MAX UNITS

Transm issi on Line Edge-coupled stripline 6 mi ls

Relative Permitti vity FR-4 or sim ilar 4.4 4.5 —

Los s Tangent FR-4 or simi lar 0.02 0.022 —

Metal Thickne ss 0.7 mi ls (0.5o z copper) 0.7 mils

Impedance Different ia l 90 100 110 