Datasheet

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General Description

The MAX3969 limiting amplifier with PECL data outputs is

ideal for low-cost ATM, Fast Ethernet, FDDI and ESCON

fiber optic receivers.

The MAX3969 features 1mV

P-P

input sensitivity and an

integrated power detector that senses the input signal

power. It provides a received-signal-strength indicator

(RSSI), which is an analog indication of the power level.

Signal strength is also indicated by the complementary

TTL loss-of-signal (LOS) outputs and the PECL signal-

detect (SD) output, both of which indicate the power

level relative to a programmable threshold.

The threshold can be adjusted to detect signal ampli-

tudes as low as 2.7mV

P-P

. An optional squelch function

disables switching of the data outputs by holding them

at a known state when the signal is below the pro-

grammed threshold.

The MAX3969 is available in die form and a 4mm x

4mm, 20-pin thin QFN package.

Applications

SFP/SFF Transceivers

Fast Ethernet/FDDI Transceivers

155Mbps LAN ATM Transceivers

ESCON Receivers

FTTx Transceivers

Features

♦ 1mV

P-P

Input Sensitivity

♦ Loss-of-Signal Detector with Programmable

Threshold

♦ TTL LOS and PECL Signal Detect

♦ Analog Received-Signal-Strength Indicator

♦ Output Squelch Function

♦ Compatible with 4B/5B Data Coding

MAX3969

200Mbps SFP Limiting Amplifier

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

150Ω 150Ω

4700pF

1μF

FILTER

0.01μF

TRANSIMPEDANCE

AMPLIFIER

DIAGNOSTIC

MONITOR

SQUELCH

IN-

IN+

CZP CZN FILTER V

CCO

INV V

GND

EP*

*EXPOSED PAD (EP) ON MAX3969ETP ONLY.

LOS

OUT+

OUT-

100kΩ

MAX3969

0.1μF

OUT+

OUT-FILT

0.1μF

+2.97V TO +3.63V

LOS

4.7kΩ

10kΩ

SFP OPTICAL RECEIVER WITH DIAGNOSTICS HOST BOARD

Typical Application Circuits

19-3251; Rev 1; 6/06

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.

EVALUATION KIT

AVAILABLE

PART

TEMP RANGE

PIN-

PACKAGE

PKG CODE

MAX3969ETP

-40°C to +85°C 20 Thin QFN

T2044-2

MAX3969E/D

— Dice* —

*Dice are designed to operate over a -40°C to +100°C junction

temperature (T

) range, but are tested and guaranteed only at

= +25°C.

Typical Application Circuits continued at end of data sheet.

Pin Configuration appears at end of data sheet.

Summary of content (11 pages)

PAGE 1
9-3251; Rev 1; 6/06 KIT ATION EVALU LE B A IL A AV 200Mbps SFP Limiting Amplifier Features The MAX3969 limiting amplifier with PECL data outputs is ideal for low-cost ATM, Fast Ethernet, FDDI and ESCON fiber optic receivers. The MAX3969 features 1mVP-P input sensitivity and an integrated power detector that senses the input signal power. It provides a received-signal-strength indicator (RSSI), which is an analog indication of the power level.
PAGE 2
MAX3969 200Mbps SFP Limiting Amplifier ABSOLUTE MAXIMUM RATINGS Power-Supply Voltage Range (VCC, VCCO) ..........-0.5V to +7.0V Voltage at FILTER, RSSI, IN+, IN-, CZP, CZN, SQUELCH, INV, VTH..................................................-0.5V to (VCC + 0.5V) TTL Output Current (LOS, LOS) .........................................±9mA PECL Output Current (OUT+, OUT-, SD) .........................±50mA Differential Voltage Between CZP and CZN..........-1.5V to +1.
PAGE 3
200Mbps SFP Limiting Amplifier OUTPUT EYE DIAGRAM (VIN = 2mVP-P, 155Mbps, 223 - 1 PRBS) SUPPLY CURRENT vs. TEMPERATURE (PECL OUTPUTS OPEN) SUPPLY CURRENT (mA) MAX3969 toc03 MAX3969 toc01 60 OUTPUT EYE DIAGRAM (VIN = 1500mVP-P, 155Mbps, 223 - 1 PRBS) MAX3969 toc02 55 50 45 40 35 30 200mV/div 200mV/div 25 20 15 10 5 0 -40 -15 10 35 60 1ns/div 1ns/div BIT ERROR RATIO vs. DIFFERENTIAL INPUT VOLTAGE RSSI VOLTAGE vs. DIFFERENTIAL INPUT VOLTAGE 85 2.40 10-06 10-07 10-08 1.20 10-12 1.00 0.
PAGE 4
Typical Operating Characteristics (continued) (VCC = +3.3V, PECL outputs terminated with 50Ω to VCC - 2V, R1 = 100kΩ, TA = +25°C, unless otherwise noted.) POWER-DETECT TIMING WITH SQUELCH (INPUT = 12mVP-P, CFILTER = 0.01μF, R2 = 15kΩ, 155Mbps, 223 - 1 PRBS) 100Mbps 1-0 PATTERN 90 LOS SD 70 60 INPUT DATA THROUGH 117MHz FILTER 50 40 UNFILTERED INPUT DATA 30 20 1.4 TRANSITION TIME (ns) OUT 80 1.6 1.2 1.0 0.8 0.6 0.4 0.
PAGE 5
200Mbps SFP Limiting Amplifier PIN NAME FUNCTION 17, 18 VCC 19 SQUELCH 20 VTH EP Exposed Pad Supply Voltage Squelch Input. The squelch function disables the data outputs by forcing OUT- low and OUT+ high when the signal is below the power-detect threshold. Connect to GND or leave unconnected to disable squelch. Connect to VCC to enable squelch. Output of Internal Op Amp that Sets Power-Detect Threshold Voltage (Figure 1).
PAGE 6
MAX3969 200Mbps SFP Limiting Amplifier Power Detector PECL Outputs Each amplifier stage contains a logarithmic FWD, which indicates the RMS input signal power. The FWD outputs are summed together at the FILTER pin where the signal is filtered by an external capacitor (CFILTER) connected between FILTER and VCC. The FILTER signal generates the RSSI output voltage (VRSSI), which is proportional to the input power in decibels. When LOS is low, VRSSI is approximated by the following equation: VRSSI (V) = 1.
PAGE 7
200Mbps SFP Limiting Amplifier MAX3969 10 log(OPTICAL POWER) VCCO PIN-TIA RESPONSIVITY = G RX_MAX (SENSITIVITY) 1.8dB SD HIGH / LOS LOW 2.5dB SD LOW / LOS HIGH OUTOUT+ ESD STRUCTURES 5dB 3.6dB VIN_TH VIN_SEN 20 log(VIN) Figure 4. Signal Levels for Power-Detect Threshold Select CFILTER For SFP/SFF, FDDI, 155Mbps ATM LAN, Fast Ethernet, and ESCON receivers, Maxim recommends CFILTER = 0.01µF. This capacitor value ensures chatter-free LOS/SD and provides a typical assert/deassert time of 10µs.
PAGE 8
Applications Information Wire Bonding For high-current density and reliable operation, the MAX3969 uses gold metalization. For best results, use gold-wire ball-bonding techniques. Use caution if attempting wedge bonding. Die pad size is 4 mils x 4 mils. Die thickness is 16 mils. Table 1 lists the bond pad coordinates for the MAX3969. The origin for pad coordinates is defined as the bottom left corner of the bottom left pad.
PAGE 9
200Mbps SFP Limiting Amplifier INV 1 FILTER 2 RSSI 3 IN- 4 IN+ 5 ORIGIN VTH SQUELCH VCC VCC LOS 20 19 18 17 16 15 LOS 14 SD 47mil (1.19mm) 6 7 8 9 10 GND GND GND CZP CZN 13 OUT- 12 OUT+ 11 VCCO 57mil (1.
PAGE 10
200Mbps SFP Limiting Amplifier MAX3969 Typical Application Circuits (continued) CAZ 1μF VCC CFILTER 0.01μF SFF OR 1 x 9 MSA RECEIVER CZP CZN 0.1μF FILTER VCC RSSI CIN 4700pF FILT LOS LOS SQUELCH SD MAX3969 IN- OUT- VCCO OUT- TRANSIMPEDANCE AMPLIFIER IN OUT+ IN+ CIN 4700pF OUT+ INV R1 100kΩ VTH EP* GND 50Ω 50Ω R2 VCC - 2V *EXPOSED PAD (EP) PAD ON MAX3969ETP ONLY.
PAGE 11
200Mbps SFP Limiting Amplifier 24L QFN THIN.EPS 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.