Rainbow Electronics MAX3645 User Manual

General Description

The MAX3645 limiting amplifier functions as a data
quantizer and is pin compatible with the Mindspeed
MC2045-2 and MC2045-2Y postamplifiers. The amplifi­er accepts a wide range of input voltages and provides
constant-level positive emitter-coupled logic (PECL)
output voltages with controlled edge speeds.

The MAX3645 features an integrated power detector
with complementary PECL loss-of-signal (LOS) outputs
that indicate when the input power level drops below a
programmable threshold. An optional squelch function
holds the data outputs at static levels during a
LOS condition.

The MAX3645 operates from a single +3.3V or +5.0V
power supply over a -40°C to +85°C temperature
range. It is available in 16-pin SO and 16-pin QSOP
packages.

Applications

SONET 155Mbps Transceivers

Fast Ethernet Receivers

FDDI 125Mbps Receivers

FTTx Receivers

ESCON Receivers

Features

♦ Pin Compatible with the Mindspeed

MC2045-2/MC2045-2Y

♦ 500µV Input Sensitivity (BER = 10

-12

)

♦ Compatible with 4B/5B Data Coding

♦ Programmable LOS Threshold

♦ Stable LOS Threshold Over Supply Range

♦ Output Disable Function and Automatic Squelch

♦ Single +3.3V or +5.0V Power Supply

♦ 18mA Supply Current

MAX3645

+2.97V to +5.5V, 125Mbps to 200Mbps Limiting

Amplifier with Loss-of-Signal Detector

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-3026; Rev 0; 10/03

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.

Pin Configuration

MAX3645

MAX3644*

PIN K

IN

V

CC

V

CC

V

CC

V

CC

OUT-

OUT+

DIN+

DIN-

GNDA

DOUT+

DOUT-

LOS

LOS

DIS

CSD

V

CCA CAZ1 CAZ2

GND

*FUTURE PRODUCT

V

CCE

TH GNDE

N.C.

0.1µF

0.1µF

C

SD

1nF

C

AZ

0.1µF

R

TH

100Ω

50Ω

50Ω 50Ω 50Ω

V

CC

- 2V

V

CC

- 2V

Typical Application Circuit

PART TEMP RANGE PIN-PACKAGE

MAX3645ESE -40°C to +85°C 16 SO

MAX3645EEE -40°C to +85°C 16 QSOP

TOP VIEW

CAZ2

CAZ1

GNDA

DIN+

DIN-

V

CCA

CSD

DIS

1

2

3

MAX3645

4

5

6

7

8

16

TH

15

N.C.

14

V

CCE

DOUT+

13

DOUT-

12

GNDE

11

LOS

10

LOS

9

SO/QSOP

MAX3645

+2.97V to +5.5V, 125Mbps to 200Mbps Limiting
Amplifier with Loss-of-Signal Detector

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +2.97V to +5.5V, PECL outputs are terminated with 50Ω to VCC- 2V, RTH= 100Ω, CAZ= 0.1µF, CSD= 1nF, TA= -40°C to
+85°C. Typical values are at V

CC

= +3.3V, 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.

Power-Supply Voltage (V

CCA

, V

CCE

) ....................-0.5V to +7.0V

Voltage at CAZ1, CAZ2, DIN+,

DIN-, CSD, DIS, TH ................................-0.5V to (V

CC

+ 0.5V)

PECL Output Current (DOUT+, DOUT-, LOS, LOS) ...........50mA

Differential Voltage between CAZ1 and CAZ2......-1.5V to +1.5V

Differential Voltage between DIN+ and DIN- ........-1.5V to +1.5V

Continuous Power Dissipation (T

A

= +85°C)

16-Pin SO (derate 8.7mW/°C above +85°C)................565mW

16-Pin QSOP (derate 8.3mW/°C above +85°C)...........540mW

Storage Ambient Temperature Range (T

S

)…….-65°C to +160°C

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

POWER SUPPLY

Supply Current I

INPUT SPECIFICATIONS

Input Resistance R

Input Sensitivity (Note 1) V

Input Overload (Note 1) V

Input-Referred Offset Voltage

Input Common-Mode Voltage V

Input-Referred RMS Noise V

DIS Input High V

DIS Input Low V

DIS Input Current IIL, I

OUTPUT SPECIFICATIONS

PECL Output-Voltage High (Notes 1, 2)

PECL Output-Voltage Low (Notes 1, 2)

PARAMETER SYM B O L CONDITIONS MIN TYP MAX UNITS

CC

IN-MIN

IN-MAX

CMM

IN-NOISE

Excludes PECL termination currents 18 27 mA

Single ended; VIN = ±200mV 3.3 4.8 6.4 kΩ

IN

Single ended 0.5

Differential 1.0

Single ended 750

Differential 1500

Unterminated input, output offset divided by
DC gain (Note 2)

(Notes 2, 3) 36 50 µV

PECL or CMOS logic

IH

PECL or CMOS logic 0

IL

0V ≤ V

IH

DIS

≤ V

CC

240µV

VCC -

0.87

V

-

CC

1160

-10 +10 µA

V

-

CC

1085

V

-

CC

1830

V

CC

V

CC

1480

VCC -

880

VCC ­1555

-

mV

mV

P-P

P-P

V

RMS

mV

mV

mV

mV

Data Output Transition Time tR, t

Pulse-Width Distortion PWD (Notes 1, 2, 4, 5) 30 200 ps

20% to 80% (Notes 1, 2, 4) 0.7 1.4 ns

F

MAX3645

+2.97V to +5.5V, 125Mbps to 200Mbps Limiting

Amplifier with Loss-of-Signal Detector

_______________________________________________________________________________________ 3

Note 1: Between sensitivity and overload, the output amplitude is >95% of the fully limited amplitude and all AC specifications are met.
Note 2: Guaranteed by design and characterization.
Note 3: Noise is derived from BER measurement.
Note 4: The data input transition time is controlled by a 4th-order Bessel filter with f

-3dB

= 0.75 × data rate.

Note 5: PWD = [(width of wider pulse) - (width of narrower pulse)] / 2, measured with 155Mbps 0011 pattern.
Note 6: All LOS specifications are measured using a 155Mbps 2

23

- 1 PRBS pattern.

Note 7: The signal at the input is switched between two amplitudes, SIGNAL_ON and SIGNAL_OFF, as shown in Figure 1.

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +2.97V to +5.5V, PECL outputs are terminated with 50Ω to VCC- 2V, RTH= 100Ω, CAZ= 0.1µF, CSD= 1nF, TA= -40°C to
+85°C. Typical values are at V

CC

= +3.3V, TA = +25°C, unless otherwise noted.)

Figure 1. Signal Levels for LOS Assert/Deassert Time
Measurement

TRANSFER CHARACTERISTICS

Bandwidth Gain = 60dB 150 250 MHz

Low-Frequency Cutoff

LOSS-OF-SIGNAL SPECIFICATIONS (Notes 2, 4, 6)

LOS Sensitivity Range 0Ω ≤ RTH ≤ 2kΩ 220mV

LOS Hysteresis 10log (V

LOS Assert/Deassert Time (Note 7) 2.3 80.0 µs

Signal-Dectect Filter Resistance R

PARAMETER SYM B O L CONDITIONS MIN TYP MAX UNITS

CAZ = open 500

= 0.1µF 0.5

C

AZ

DEASSERT/VASSERT

RTH = 0Ω, low setting 0.5 0.9 1.3

RTH = 1kΩ, medium setting 4.8 6.6 8.3LOS Assert Level

= 2kΩ, high setting 12 17 22

R

TH

RTH = 0Ω, low setting 1.1 1.5 1.9

RTH = 1kΩ, medium setting 8.0 10.8 13.5LOS Deassert Level

= 2kΩ, high setting 20 28 36

R

TH

Pin 7 14 20 26 kΩ

SD

kHz

) 1.4 2 dB

mV

mV

P-P

P-P

P-P

V

IN

SIGNAL ON

1dB

6dB MAXIMUM POWER-DETECT WINDOW

0V

MAXIMUM DEASSERT LEVEL

MINIMUM ASSERT LEVEL

SIGNAL OFF

TIME