_______________General Description

The MAX3761/MAX3762 limiting amplifiers, with 4mV

sensitivity and PECL data outputs, are optimized for

operation in low-cost, 622Mbps, LAN/ATM LAN fiber

optics applications.

An integrated power detector senses the input signal’s

amplitude. A received-signal-strength indicator (RSSI)

gives an analog indication of the power level, while the

complementary loss-of-signal (LOS) outputs indicate if

the input power level exceeds the programmed

threshold level. The LOS threshold can be adjusted to

detect signal amplitudes between 3mVp-p and

100mVp-p, providing a 15dB LOS adjustment in fiber

optic receivers. The LOS outputs have 3.5dB of

hysteresis, which prevents chatter when input signal

levels are small. The MAX3761’s LOS outputs are com-

patible with TTL-logic levels. The MAX3762 has PECL

LOS outputs.

DISABLE and LOS can be used to implement a squelch

function, which turns off the data outputs when the

input signal is below the programmed threshold.

________________________Applications

622Mbps LAN/ATM LAN Receivers

155Mbps LAN/ATM LAN Receivers

____________________________Features

o Chatter-Free Power Detector with Programmable

Loss-of-Signal Outputs

o 4mV Input Sensitivity (PECL Loss-of-Signal

Interface Logic—MAX3766

o PECL Data Outputs

o Single 5V Power Supply

o 250ps Output Edge Speed

o Low 15ps Pulse-Width Distortion

o TTL Loss-of-Signal Interface Logic—MAX3761

Low-Power, 622Mbps Limiting Amplifiers

with Chatter-Free Power Detect for LANs

________________________________________________________________ Maxim Integrated Products

1

CZN

OUT+

OUT-

LOS-

LOS+

DISABLE

SUB

GND

GNDO

100pF

50

Ω

CZP

R1

100k

Ω

R2

22k

Ω

VTH

INV

MAX3761

150pF

50

Ω

EN

RSSI

VCCO

VIN+

10nF

100pF

BYPASS

SUPPLY

5.6nF

5.6nF

+5V

VIN-

FILTER

_________Typical Operating Circuits

19-1097; Rev 3; 7/04

PART

MAX3761EEP

MAX3761C/D

MAX3762EEP

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

TEMP RANGE

PIN-PACKAGE

20 QSOP

Dice*

20 QSOP

EVALUATION

KIT

AVAILABLE

Ordering Information

+Denotes lead free package.

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.

MAX3762EEP+

-40°C to +85°C

20 QSOP

MAX3762C/D

-40°C to +85°C

Dice*

__________________Pin Configuration

20

19

18

17

16

15

14

13

1

2

3

4

5

6

7

8

DISABLE

LOS+

LOS-

EN

RSSI

FILTER

TOP VIEW

VCCO

OUT+

OUT-

GNDO

SUB

GND

VIN-

VIN+

12

11

9

10

VTH

INV

CZN

CZP

QSOP

MAX3761

MAX3762

MAX3762 at end of data sheet.