Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - laser controller Laser diode driver (LWL) TQFP 32 EP Surface-mount

General Description

The MAX3869 is a complete, single +3.3V laser driver

for SDH/SONET applications up to 2.5Gbps. The

device accepts differential PECL data and clock inputs

and provides bias and modulation currents for driving a

laser. A synchronizing input latch can be used (if a

clock signal is available) to reduce jitter.

An automatic power control (APC) feedback loop is

incorporated to maintain a constant average optical

power over temperature and lifetime. The wide modula-

tion current range of 5mA to 60mA and bias current of

1mA to 100mA are easy to program, making this prod-

uct ideal for use in various SDH/SONET applications.

The MAX3869 also provides enable control, two current

monitors that are directly proportional to the laser bias and

modulation currents, and a failure-monitor output to indi-

cate when the APC loop is unable to maintain the average

optical power. The MAX3869 is available in 32-pin TQFP

and small 32-pin QFN packages as well as dice.

Applications

SONET/SDH Transmission Systems

Add/Drop Multiplexers

Digital Cross-Connects

Section Regenerators

2.5Gbps Optical Transmitters

Features

♦ Single +3.3V or +5V Power Supply

♦ 64mA Supply Current at +3.3V

♦ Programmable Bias Current from 1mA to 100mA

♦ Programmable Modulation Current from

5mA to 60mA

♦ Bias Current and Modulation Current Monitors

♦ 87ps Rise/Fall Time

♦ Automatic Average Power Control with Failure

Monitor

♦ Complies with ANSI, ITU, and Bellcore

SDH/SONET Specifications

♦ Enable Control

*Exposed pad.

**Package Code: G3255-1

***Dice are designed to operate over this range, but are tested and

guaranteed at T

= +25°C only. Contact factory for availability.

+Denotes lead-free package.

Ordering Information

MAX3869

+3.3V, 2.5Gbps SDH/SONET Laser Driver

with Current Monitors and APC

________________________________________________________________ Maxim Integrated Products 1

EVALUATION KIT

AVAILABLE

124Ω 124Ω

SERIALIZER

WITH

CLOCK GEN.

124Ω

23Ω

25Ω

+3.3V

0.056µF

0.01µF

BIASMON

MODMON

+3.3V

1000pF

BIASMAX

LATCH

ENABLE

FAIL

MODSET

APCSET

APCFILT

CLK-

CLK+

DATA-

DATA+

FERRITE

BEAD

OUT+

BIAS

OUT-

CAPC

124Ω

84.5Ω 84.5Ω 84.5Ω84.5Ω

MAX3869

MAX3890

Typical Application Circuit

19-1570; Rev 4; 1/05

Pin Configuration appears at end of data sheet.

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.

PART TEMP RANGE PIN-PACKAGE

MAX3869EHJ -40°C to +85°C 32 TQFP-EP*

MAX3869EHJ+ -40°C to +85°C 32 TQFP-EP*

MAX3869EGJ -40°C to +85°C 32 QFN**

MAX3869E/D -40°C to +85°C Dice***

Summary of content (15 pages)

PAGE 1
9-1570; Rev 4; 1/05 KIT ATION EVALU E L B A IL AVA +3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC Features The MAX3869 is a complete, single +3.3V laser driver for SDH/SONET applications up to 2.5Gbps. The device accepts differential PECL data and clock inputs and provides bias and modulation currents for driving a laser. A synchronizing input latch can be used (if a clock signal is available) to reduce jitter.
PAGE 2
MAX3869 +3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC............................................. -0.5V to +7.0V Current into BIAS ...........................................-20mA to +150mA Current into OUT+, OUT- ................................-20mA to +100mA Current into MD.....................................................-5mA to +5mA Voltage at DATA+, DATA-, CLK+, CLK-, ENABLE, LATCH, FAIL, BIASMON, MODMON .....-0.5V to (VCC + 0.
PAGE 3
+3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC (VCC = +3.14V to +5.5V, load as shown in Figure 2, TA = -40°C to +85°C. Typical values are at VCC = +3.3V, IMOD = 30mA, TA = +25°C.
PAGE 4
MAX3869 +3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC VCC tCLK = 402ps A A A, B ARE SMD FERRITE BEADS: B = BLM11A601S MURATA ELECTRONICS A = BLM21A102S MURATA ELECTRONICS CLK tSU B 25Ω B tH DATA MAX3869 0.056µF OUTIOUT+ Figure 3. Setup/Hold Time Definition OSCILLOSCOPE OUT+ 0.056µF BIAS 15Ω 50Ω 50Ω VCC Figure 2. Output Termination for Characterization Typical Operating Characteristics (VCC = +3.3V, load as shown in Figure 2, TA = +25°C, unless otherwise noted.
PAGE 5
+3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC RANDOM JITTER vs. IMOD 8.0 7.5 RANDOM JITTER (psp-p) 7.0 400mV/div 250mV/div MAX3869-05 MAX3869-04 ELECTRICAL EYE DIAGRAM (IMOD = 60mA, 213-1 +80 CID, 32 TQFP-EP) MAX3869-06 ELECTRICAL EYE DIAGRAM (IMOD = 30mA, 213-1 +80 CID, 32 TQFP-EP) 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 100ps/div 50 40 0.8 0.7 0.6 0.5 0.1 0 0 1 300 10 RBIASMAX (kΩ) 100 1 IBIAS = 100mA, IMOD = 50mA GAIN (IBIAS/IBIASMON) 40 VCC = +3.
PAGE 6
Typical Operating Characteristics (continued) (VCC = +3.3V, load as shown in Figure 2, TA = +25°C, unless otherwise noted.) MODULATION-CURRENT MONITOR GAIN vs. TEMPERATURE PULSE-WIDTH DISTORTION vs. IMOD 35 IBIAS = 100mA, IMOD = 50mA 30 20 VCC = +3.3V IBIAS = 10mA, IMOD = 10mA PWD (ps) 25 MAX3869-13 25 MAX3869-12 40 GAIN (IMOD/IMODMON) MAX3869 +3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC 20 15 10 15 VCC = +5V 10 5 5 0.
PAGE 7
+3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC PIN NAME FUNCTION 20 OUT- Negative Modulation-Current Output. IMOD flows through this pad when input data is low. 22 GND4 Ground for Output Circuitry 23 GND3 Ground for APC 24 MD 25 VCC3 Power Supply for APC 26 CAPC A capacitor connected from this pad to ground controls the dominant pole of the APC feedback loop (CAPC = 0.1µF). 27 GND2 Ground for Internal Reference 28 N.C.
PAGE 8
MAX3869 +3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC VCC LP2 LATCH LP1 RP MAX3869 RD OUT+ IMOD 0 CD MUX DATA D Q 1 OUT- CLK 25Ω VCC ENABLE IBIAS BIASMON 165x IBIAS 37 BIAS 40x 5x MD MOBMON 1000pF IMD IMOD 29 FAILURE DETECTOR MODSET CAPC BIASMAX APCSET FAIL RMODSET RBIASMAX CAPC RAPCSET Figure 4. Functional Diagram laser package is used to convert the optical power into a photocurrent.
PAGE 9
+3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC Programming the Modulation Current For a given laser power PAVG, slope efficiency (η), and extinction ration (re), the modulation current can be calculated using Table 1. See the IMOD vs. RMODSET graph in the Typical Operating Characteristics and select the value of RMODSET that corresponds to the required current at +25°C. Enable Control The MAX3869 incorporates a laser driver enable function.
PAGE 10
MAX3869 +3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC should equal 25Ω. Typical values for RD are 18Ω to 23Ω. For best performance, a bypass capacitor (0.01µF typical) should be placed as close as possible to the anode of the laser diode. Depending on the exact characteristics of the laser diode and PC board layout, a resistor (RP) of 20Ω to 70Ω in parallel with pull-up inductor LP1 can be useful in damping overshoot and ringing in the optical output.
PAGE 11
+3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC Layout Considerations To minimize inductance, keep the connections between the MAX3869 output pins and LD as close as possible. Optimize the laser diode performance by placing a bypass capacitor as close as possible to the laser anode. Use good high-frequency layout techniques and multilayer boards with uninterrupted ground planes to minimize EMI and crosstalk. IBIASMAX = ITH(MAX) + IMOD/2 In this example, IBIASMAX = 68.1mA.
PAGE 12
MAX3869 +3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC VCC2 BIASMAX MODSET APCSET N.C. GND2 CAPC VCC3 Pin Configurations 32 31 30 29 28 27 26 25 TOP VIEW Chip Topography CLKVCC1 VCC1 VCC1 DATA+ GND1 CLK+ GND1 DATA- VCC1 GND1 GND2 VCC2 LATCH VCC1 1 24 MD DATA+ 2 DATA- 3 ENABLE BIASMAX 23 GND3 GND1 MODSET 22 GND4 GND1 BIASMON GND2 APCSET MODMON N.C.
PAGE 13
+3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC 32L,TQFP.EPS PACKAGE OUTLINE, 32L TQFP, 5x5x1.0mm, EP OPTION 21-0079 F 1 2 ______________________________________________________________________________________ 13 MAX3869 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.
PAGE 14
MAX3869 +3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) PACKAGE OUTLINE, 32L TQFP, 5x5x1.
PAGE 15
+3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC 32L QFN.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.