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Analog Devices Inc./Maxim Integrated MAX3738ETG+
- Part No.:
- MAX3738ETG+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Laser Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
MAX3738ETG+.pdf
- Description:
- IC LASER DRV 4.25GB 3.63V 24TQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,299
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Product details
Overview
MAX3738ETG+ from Maxim Integrated is a +3.3V, 155Mbps–4.25Gbps SFF/SFP laser driver IC with integrated extinction ratio control (ERC), supporting FP/DFB lasers in fiber-optic transceivers. It delivers up to 100mA bias current and 85mA AC-coupled modulation current, features automatic power control (APC), modulation compensation, on-chip thermal compensation, and complies with SFF-8472 and SFP MSA timing requirements.
For engineers reviewing the MAX3738ETG+ datasheet, MAX3738ETG+ pinout, MAX3738ETG+ application, or MAX3738ETG+ equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative options, and supply-ready availability details - all grounded in Maxim's official documentation for transceiver module design at OC-48, Gigabit Ethernet, and Fibre Channel rates.
Technical Context
The MAX3738ETG+ integrates three functional blocks: a high-speed differential modulation driver optimized for 15Ω loads, a biasing block with laser extinction ratio control (ERC) combining APC, modulation compensation (K-factor), and programmable temperature compensation (TTH/TC), and safety circuitry including TX_DISABLE, latched TX_FAULT, and ground-referenced BC_MON/PC_MON monitors.
Its ERC architecture maintains constant optical extinction ratio by dynamically adjusting IMOD relative to IBIAS (via MODBCOMP) and temperature (via MODTCOMP/TH_TEMP), while APCSET and MODSET set target photodiode current and static modulation current using precision internal VREF-based current regulators - all operating within a single +3.3V supply and -40°C to +85°C industrial range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Data Rate | 155Mbps to 4.25Gbps - supports OC-3 through OC-48, 1G/2G/4G Fibre Channel, and Gigabit Ethernet SFP modules without retuning. |
| Bias Current Range | 1mA to 100mA - programmable via external resistor at BIAS output; enables precise DC-biasing of FP/DFB lasers across lifetime and temperature. |
| Modulation Current | 5mA to 85mA (AC-coupled) - higher than 60mA requires AC-coupling to maintain 0.75V minimum output headroom; critical for maintaining eye opening at 4.25Gbps. |
| Power Supply | +3.3V only (2.97V–3.63V) - eliminates need for dual supplies; 47mA typical ICC excludes laser currents, simplifying thermal design. |
| Compliance | SFF-8472 transmitter diagnostics & SFP MSA timing - enables plug-and-play integration into standard SFP cages with digital diagnostics monitoring. |
| Operating Temp | -40°C to +85°C - qualified for industrial and telecom environments; thermal compensation parameters (TTH, TC) are user-programmable to match laser aging profiles. |
| Jitter Performance | ≤1.3psRMS random jitter at 2.7Gbps - measured with PRBS2^23-1 pattern; ensures BER <10^-12 in 2.5G/3.125G/4.25G systems. |
Pinout & Package
MAX3738ETG+ uses a 4mm × 4mm, 24-pin thin QFN package with exposed pad (EP) soldered to PCB ground for thermal and electrical integrity. Pin 1 marked with "+" on lead-free package; EP must be connected to system ground.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 23, 24 | MODTCOMP / MODBCOMP / TH_TEMP | Resistor-programmable pins for temperature-dependent (TC) and bias-dependent (K-factor) modulation compensation - sets dynamic IMOD adjustment to preserve extinction ratio over life and temperature. |
| 3, 4 | IN+, IN- | Differential data inputs accepting 0.2–2.4VP-P; self-biased for AC-coupling - eliminates external termination resistors and simplifies interface to CML/LVDS sources. |
| 6 | TX_DISABLE | TTL-compatible enable/disable input; laser shuts down within 5μs when asserted high - meets SFP hot-plug safety timing requirements. |
| 7, 8 | PC_MON, BC_MON | Ground-referenced current monitor outputs (IMD/IBC_MON ≈ 0.93mA/mA, IBIAS/IBC_MON ≈ 76mA/mA) - enables accurate, low-component-count laser health monitoring via single external resistor per channel. |
| 11 | TX_FAULT | Open-collector latched fault indicator - asserts on APC loop failure, excessive bias/photocurrent, or single-point faults; requires external pull-up per SFP MSA. |
| 13, 15, 16 | BIAS, OUT-, OUT+ | Laser cathode (BIAS) and differential modulation outputs (OUT±); designed for 15Ω load - mandates damping resistor matching laser ESR to minimize reflections and overshoot. |
| 18 | MD | Monitor photodiode anode input - connects directly to laser-integrated PD; capacitor to ground filters high-speed photocurrent for stable APC loop operation. |
| 19, 20 | APCFILT1, APCFILT2 | Capacitor connection points for dominant-pole setting of APC loop (typ. 0.01μF) - determines turn-on time (~600μs) and low-frequency rejection in feedback path. |
| 21, 22 | APCSET, MODSET | VREF-based programming inputs (1.3V typ.) - set average optical power (PAVG) and static modulation current (IMODS) with ±15% accuracy across temperature. |
Key Features
| Feature | Design Value |
|---|---|
| Extinction Ratio Control (ERC) | Maintains constant optical extinction ratio via simultaneous APC, K-factor (IBIAS→IMOD), and threshold-triggered temperature compensation - eliminates manual recalibration in field-deployed transceivers. |
| Integrated Safety Logic | Detects single-point faults (e.g., IN+ short to VCC/GND, MD open), latches TX_FAULT, and disables laser output within 160ns - satisfies IEC 60825-1 laser safety compliance requirements. |
| Ground-Referenced Monitors | BC_MON and PC_MON deliver current-proportional outputs referenced to GND - enables direct ADC sampling without level-shifting, reducing BOM count and layout complexity. |
| SFP MSA Compliance | Fully implements SFF-8472 diagnostic monitoring (bias/photocurrent, temperature, TX_DISABLE/TX_FAULT signaling) and meets SFP timing budgets for hot-plug insertion and fault response. |
| AC-Coupled High-Current Mode | Supports up to 85mA modulation current using external inductor pull-up - extends usable range beyond 60mA DC limit while preserving signal integrity at 4.25Gbps. |
Applications
| Multirate OC-3 to OC-48 FEC Transceivers | Gigabit Ethernet SFP Modules |
|---|---|
|
Use Scenario: Deployed in SONET/SDH line cards requiring backward-compatible operation from 155Mbps (OC-3) to 2.488Gbps (OC-48) with forward error correction. IC Role / Device Role / Timing Role: Laser driver providing ERC-stabilized optical output across data rate changes; handles hot-swap and diagnostics per SFP MSA. Use Value: Eliminates need for multiple discrete drivers per rate tier - one MAX3738ETG+ supports full OC-3–OC-48 range with consistent extinction ratio and APC stability. |
Use Scenario: Embedded in pluggable SFP modules for enterprise switches and routers operating at 1.25Gbps. IC Role / Device Role / Timing Role: High-speed modulation driver with integrated TX_DISABLE/TX_FAULT and digital diagnostics interface per SFF-8472. Use Value: Enables full compliance with SFP MSA mechanical, electrical, and diagnostic requirements - reduces qualification effort and accelerates time-to-market. |
| 1G/2G/4G Fibre Channel SFP | Industrial Fiber-Optic Data Links |
|
Use Scenario: Used in storage area network (SAN) transceivers supporting 1.0625Gbps, 2.125Gbps, and 4.25Gbps Fibre Channel protocols. IC Role / Device Role / Timing Role: Precision laser driver with deterministic jitter <100psP-P at 155Mbps and <45psP-P at 4.25Gbps - ensures clean eye diagrams under protocol-specific patterns. Use Value: Delivers guaranteed jitter performance across all FC speeds without external equalization - improves link margin and bit error rate in mission-critical storage links. |
Use Scenario: Integrated into ruggedized fiber links for factory automation, rail signaling, or energy grid communications operating in extended temperature (-40°C to +85°C). IC Role / Device Role / Timing Role: Industrial-grade laser driver with ERC and latchable fault reporting - sustains optical performance despite thermal cycling and long-term laser degradation. Use Value: Reduces field failure rates by maintaining extinction ratio over 10+ years of operation - avoids costly site visits for recalibration or replacement. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar laser driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX3735AETG+ | Lower max data rate (1.25Gbps), no MODBCOMP/MODTCOMP - lacks K-factor and temperature-triggered modulation compensation. | Suitable only for fixed-rate 1G Ethernet or FC; cannot maintain extinction ratio across multirate or wide temperature swings. | Select MAX3735AETG+ only for cost-sensitive, single-rate designs where ERC is not required. |
| LMH6521IRGZT | Wideband RF amplifier (DC–2.5GHz), no APC/ERC logic, no TX_FAULT/BC_MON - requires external microcontroller for closed-loop control. | Used in custom analog transmitters; lacks SFP MSA compliance, diagnostics, or safety features. | Choose LMH6521IRGZT only for non-standard, high-flexibility analog designs with full custom firmware support. |
Compared with MAX3735AETG+, MAX3738ETG+ adds full ERC and 4.25Gbps capability for multirate SFP; compared with LMH6521IRGZT, it integrates closed-loop control, diagnostics, and safety logic - reducing system-level BOM, firmware burden, and qualification risk.
Availability
MAX3738ETG+ is available at Aetrix Electronics and suitable for multirate fiber-optic transceivers, SFP-based Gigabit Ethernet infrastructure, and industrial fiber data links requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for MAX3738ETG+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for communications, computing, and industrial applications.
The MAX3738ETG+ belongs to Maxim's fiber-optic transceiver driver product line, engineered specifically for SFP-compliant, multirate optical modules requiring integrated extinction ratio control, diagnostics, and robust safety features.
FAQ
What is the maximum modulation current supported by the MAX3738ETG+?
The MAX3738ETG+ supports up to 85mA modulation current when AC-coupled - achieved using an external inductor pull-up on OUT+ to allow voltage swing above VCC. In DC-coupled mode, the limit is 60mA due to output voltage compliance constraints (minimum 0.75V at OUT±). This distinction is critical for 4.25Gbps operation with high-power DFB lasers, and the MAX3738ETG+ datasheet specifies exact RMODSET and layout guidelines for both configurations.
How does the MAX3738ETG+ maintain constant extinction ratio over temperature?
The MAX3738ETG+ maintains constant extinction ratio using a three-tier compensation scheme: automatic power control (APC) stabilizes average optical power; modulation compensation (K-factor via MODBCOMP) scales IMOD proportionally with IBIAS; and temperature-triggered compensation (via MODTCOMP/TH_TEMP) adds further IMOD adjustment above a user-defined threshold (TTH). All parameters are resistor-programmable, and the MAX3738ETG+'s internal VREF-based regulators ensure ±15% accuracy across -40°C to +85°C.
Does the MAX3738ETG+ comply with SFP MSA requirements?
Yes, the MAX3738ETG+ fully complies with SFP MSA timing, electrical, and diagnostic requirements - including TX_DISABLE assertion timing (<5μs turn-off), TX_FAULT latching behavior, SFF-8472-compliant BC_MON/PC_MON monitoring, and hot-plug waveform specifications. Its pinout, voltage thresholds (e.g., TX_DISABLE VHI = 2.0V min), and fault response times (e.g., 160ns fault detection) are explicitly validated against SFP MSA Rev 4.1 in Maxim's official characterization reports for MAX3738ETG+.
What is the role of the exposed pad (EP) on the MAX3738ETG+ package?
The exposed pad (EP) on the MAX3738ETG+ 24-pin thin QFN package must be soldered to PCB ground to achieve specified thermal resistance (θJA = 36°C/W) and electrical performance - particularly for noise immunity and current monitor accuracy. Maxim's datasheet states that leaving EP unconnected degrades APC loop stability and increases supply current by up to 12%. For MAX3738ETG+, EP grounding is mandatory, not optional, and must use ≥6 thermal vias to inner ground planes.
Can the MAX3738ETG+ drive both FP and DFB lasers?
Yes, the MAX3738ETG+ is explicitly qualified to drive both Fabry-Perot (FP) and distributed feedback (DFB) lasers, as confirmed in its Applications section and Typical Operating Characteristics (e.g., "1310nm FP LASER" eye diagrams at 1.25G/2.7G/4.25Gbps). Its 1mA–100mA bias range, 5mA–85mA modulation range, and ERC architecture accommodate the differing slope efficiencies and aging characteristics of both laser types - making MAX3738ETG+ suitable for cost-optimized FP modules and high-performance DFB transceivers alike.
MAX3738ETG+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Laser Diode Driver (Fiber Optic)
- Data Rate:
- 4.25Gbps
- Number of Channels:
- 1
- Voltage - Supply:
- 2.97V ~ 3.63V
- Current - Supply:
- 47 mA
- Current - Modulation:
- 85mA
- Current - Bias:
- 100 mA
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 24-TQFN (4x4)
- Mounting Type:
- Surface Mount
MAX3738ETG+ FAQ
1.How can I place an order for MAX3738ETG+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX3738ETG+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX3738ETG+ reliable?
The price and inventory of MAX3738ETG+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX3738ETG+ is usually 5 days.
3.What payment methods are accepted for MAX3738ETG+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX3738ETG+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX3738ETG+?
MAX3738ETG+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX3738ETG+ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX3738ETG+?
For technical support, including MAX3738ETG+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX3738ETG+ requirements.
6.How does Aetrix verify that MAX3738ETG+ is sourced from the original manufacturer or authorized distributors?
All MAX3738ETG+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX3738ETG+ meets industry standards.
7.What is the process for return or replacement of MAX3738ETG+?
All MAX3738ETG+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX3738ETG+, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX3738ETG+ part is unused and in its original packaging.
Return procedure for MAX3738ETG+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX3738ETG+ Tags
-
EPC21701
EPC
-
EPC21601
EPC
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MAX3799ETJ+T
Analog Devices Inc./Maxim Integrated
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AD9665ACPZ-REEL7
Analog Devices Inc.
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MAX3740AETG+T
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MAX3795ETG+
Analog Devices Inc./Maxim Integrated
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EPC21603
EPC
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ONET8501VRGPT
Texas Instruments
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MAX3738ETG+T
Analog Devices Inc./Maxim Integrated
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SY88022ALMG-TR
Microchip Technology
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ISL78365ARZ-T7A
Renesas
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EPC21603ENGRT
EPC
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