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Home > Products > Integrated Circuits (ICs) > Linear > Special Purpose Amplifiers

Analog Devices Inc./Maxim Integrated MAX3268CUB+T

Name: MAX3268CUB+T
Brand: Analog Devices Inc./Maxim Integrated
SKU: MAX3268CUB+T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MAX3268CUB+T

Manufacturer:: Analog Devices Inc./Maxim Integrated

Category:: Special Purpose Amplifiers

Package:: 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad

Datasheet:: MAX3268CUB+T.pdf

Description:: IC LIMITING AMP 10UMAX

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MAX3268CUB+T from Maxim Integrated is a 1.25Gbps PECL-output limiting amplifier for optical receiver front-ends, featuring programmable loss-of-signal (LOS) detection with RTH-based threshold setting, 300ps max edge speed, 14ps deterministic jitter, and operation from +3.0V to +5.5V supply. It interfaces directly with transimpedance amplifiers like MAX3266/MAX3267 in Gigabit Ethernet SFF receivers.

For engineers reviewing the MAX3268CUB+T datasheet, MAX3268CUB+T pinout, MAX3268CUB+T application, or MAX3268CUB+T equivalent, key selection criteria include its 10-pin µMAX-EP package, PECL output compatibility with VCC − 2V termination, LOS hysteresis of 2.5–4.4dB, input voltage range of 10–1200mV_PP, and guaranteed operation from 0°C to +70°C.

Technical Context

The MAX3268CUB+T implements a multistage limiting amplifier architecture with integrated RMS power detection and offset correction via CAZ1/CAZ2 lowpass filtering. Its PECL output stage is designed for direct connection to 50Ω transmission lines terminated at VCC − 2V, delivering controlled edge speeds without external equalization.

It uses a 100Ω differential input impedance matched to TIA outputs, supports programmable LOS assertion via external RTH (2.5kΩ–20kΩ), and includes internal 16kΩ pullups on LOS/LOS pins. The squelch function is unconnected per datasheet-no SQUELCH pin control is available in this 10-pin µMAX variant.

Key Specifications

Parameter	Value and Actual Design Meaning
Data Rate	1.25Gbps - supports full-rate Gigabit Ethernet and Fibre Channel 1x operation
Deterministic Jitter	14ps_P-P - meets jitter budget requirements for 1.25Gbps serial links with Bessel-filtered inputs
Input Voltage Range	10–1200mV_PP - accommodates wide dynamic range from TIAs without clipping
Edge Speed	300ps max - ensures clean signal integrity into 50Ω PECL loads
LOS Hysteresis	2.5–4.4dB - provides stable optical signal detect with 2.2dB optical hysteresis
Supply Voltage	+3.0V to +5.5V - enables interoperability with 3.3V and 5V system rails
Operating Temp	0°C to +70°C - qualified for commercial-grade optical module environments

Pinout & Package

MAX3268CUB+T is housed in a 10-pin µMAX-EP package (3.0mm × 3.0mm, 0.8mm height) with exposed paddle soldered to PCB ground for thermal management.

Pin/Terminal	Circuit Role	Design Meaning
1, 2	VCC	Positive supply input - requires local 0.1µF bypass capacitor to ground
3	IN+	Noninverted differential input - 100Ω impedance referenced to IN−
4	IN−	Inverted differential input - forms 100Ω differential pair with IN+
5	TH	LOS threshold programming node - connects to ground via RTH (2.5kΩ–20kΩ)
6	CAZ1	Offset correction loop capacitor terminal - open for f_OC = 2MHz (8B/10B)
7, 8	OUT+, OUT−	PECL differential data outputs - terminate to VCC − 2V with 50Ω each
9	LOS	Inverted loss-of-signal output - TTL-compatible, internally pulled up to 16kΩ
10	LOS	Noninverted loss-of-signal output - complementary to pin 9, same pullup

Key Features

Feature	Design Value
PECL Output Interface	Standards-compliant outputs with VCC − 2V termination - eliminates need for level-shifting in SFF modules
Programmable LOS Threshold	RTH resistor sets assert/deassert levels across 3 sensitivity ranges - enables precise optical power detection tuning
Low Input-Referred Noise	150µV_RMS - preserves SNR when amplifying weak TIA outputs
Differential Input Impedance	100Ω matched - minimizes reflections when driven by MAX3266/MAX3267 TIAs
Integrated Offset Correction	CAZ1/CAZ2 configurable time constant - suppresses DC drift below 100µV, reducing deterministic jitter

Applications

Gigabit Ethernet SFF Receivers	Fibre Channel 1x Receivers
Use Scenario: Compact optical transceivers for 1000BASE-SX/LX/ZX links requiring minimal board area and low power. IC Role / Device Role / Timing Role: Final-stage limiting amplifier converting analog TIA output to clean, jitter-controlled PECL data stream. Use Value: 300ps edge speed and 14ps deterministic jitter ensure compliance with IEEE 802.3 Clause 38 eye mask requirements.	Use Scenario: FC-AL and FC-PH-2 compliant 1.0625Gbps optical modules used in storage area networks. IC Role / Device Role / Timing Role: Signal conditioning block providing LOS indication and amplitude limiting prior to CDR input. Use Value: Programmable RTH-based LOS hysteresis delivers robust optical link monitoring across temperature and aging.
Small-Form-Factor (SFF) Modules	GBIC Optical Subassemblies
Use Scenario: Hot-pluggable 2×5-pin SFF modules where footprint and thermal performance are critical. IC Role / Device Role / Timing Role: High-density PECL driver enabling direct interface to backplane traces or laser driver inputs. Use Value: 10-pin µMAX-EP package (3.0×3.0mm) reduces PCB area by >40% vs. 16-pin TSSOP alternatives.	Use Scenario: GBIC modules requiring TTL-compatible LOS signaling to host controller with high-impedance disable. IC Role / Device Role / Timing Role: Dual LOS output generator (LOS/LOS) meeting GBIC specification for open-drain signaling. Use Value: Internal 16kΩ pullups eliminate external resistors while maintaining <0.4V low-level and >2.4V high-level TTL thresholds.

Gigabit Ethernet SFF Receivers

Fibre Channel 1x Receivers

Use Scenario: Compact optical transceivers for 1000BASE-SX/LX/ZX links requiring minimal board area and low power.

IC Role / Device Role / Timing Role: Final-stage limiting amplifier converting analog TIA output to clean, jitter-controlled PECL data stream.

Use Value: 300ps edge speed and 14ps deterministic jitter ensure compliance with IEEE 802.3 Clause 38 eye mask requirements.

Use Scenario: FC-AL and FC-PH-2 compliant 1.0625Gbps optical modules used in storage area networks.

IC Role / Device Role / Timing Role: Signal conditioning block providing LOS indication and amplitude limiting prior to CDR input.

Use Value: Programmable RTH-based LOS hysteresis delivers robust optical link monitoring across temperature and aging.

Small-Form-Factor (SFF) Modules

GBIC Optical Subassemblies

Use Scenario: Hot-pluggable 2×5-pin SFF modules where footprint and thermal performance are critical.

IC Role / Device Role / Timing Role: High-density PECL driver enabling direct interface to backplane traces or laser driver inputs.

Use Value: 10-pin µMAX-EP package (3.0×3.0mm) reduces PCB area by >40% vs. 16-pin TSSOP alternatives.

Use Scenario: GBIC modules requiring TTL-compatible LOS signaling to host controller with high-impedance disable.

IC Role / Device Role / Timing Role: Dual LOS output generator (LOS/LOS) meeting GBIC specification for open-drain signaling.

Use Value: Internal 16kΩ pullups eliminate external resistors while maintaining <0.4V low-level and >2.4V high-level TTL thresholds.

Equivalent & Alternatives

The following parts are listed as comparable options for similar limiting amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX3268CUB	Same silicon, non-lead-free packaging - RoHS exemption applies; no Pb-free finish	Identical electrical and thermal specs - suitable for legacy industrial assemblies not requiring lead-free compliance	Select MAX3268CUB+T for new designs requiring RoHS compliance; use MAX3268CUB only if Pb-free is prohibited by end-equipment standard
MAX3768CUB+	Extended temperature grade (−40°C to +85°C); otherwise identical pinout, functionality, and AC specs	Required for extended-temp optical modules deployed in outdoor or industrial enclosures	Choose MAX3268CUB+T for commercial-grade SFF receivers; select MAX3768CUB+ when operating beyond 0°C–70°C ambient range

Compared with MAX3268CUB and MAX3768CUB+, the MAX3268CUB+T offers identical 1.25Gbps PECL performance and µMAX footprint but adds lead-free (Pb-free) termination for RoHS-compliant manufacturing, while MAX3768CUB+ extends operational range to industrial temperatures without altering interface behavior.

Availability

MAX3268CUB+T is available at Aetrix Electronics and suitable for Gigabit Ethernet SFF receivers, Fibre Channel 1x optical modules, and small-form-factor transceiver assemblies requiring stable component supply, consistent parametric yield, and long-term production support.

Supply support for MAX3268CUB+T 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 RF ICs for communications, computing, and industrial systems.

The MAX326x family was designed specifically for optical receiver signal conditioning - delivering low-jitter limiting amplification, programmable LOS detection, and industry-standard CML/PECL outputs in space-constrained packages.

FAQ

What is the correct termination for MAX3268CUB+T PECL outputs?

The MAX3268CUB+T PECL outputs must be terminated to VCC − 2V using two 50Ω resistors - one from OUT+ to VCC − 2V and one from OUT− to VCC − 2V. This matches the standard PECL interface requirement and ensures optimal signal integrity, edge speed, and jitter performance. AC-coupling is permitted but requires careful DC biasing of the load side.

Does MAX3268CUB+T support the squelch function?

No, the MAX3268CUB+T does not support the squelch function. Per the datasheet Pin Description section, "In the MAX3265/MAX3268/MAX3269 10-pin µMAX, SQUELCH is not connected." The SQUELCH pin is unimplemented in this package variant, so output muting based on LOS state is not available.

What is the purpose of the CAZ1 and CAZ2 pins on MAX3268CUB+T?

The CAZ1 and CAZ2 pins on MAX3268CUB+T form the external node for the offset-correction loop capacitor. When left open, they set the offset correction time constant to 2MHz - optimal for 8B/10B encoded signals like Gigabit Ethernet. For scrambled NRZ (e.g., ATM), a 0.1µF capacitor between CAZ1 and CAZ2 lowers f_OC to ~2kHz to prevent duty-cycle distortion.

How is loss-of-signal (LOS) threshold programmed on MAX3268CUB+T?

The LOS threshold on MAX3268CUB+T is programmed by connecting an external resistor RTH from pin 5 (TH) to ground. Values from 2.5kΩ (low sensitivity) to 20kΩ (high sensitivity) set corresponding LOS assert levels from 2.2mV to 41.5mV differential input. Graphs in the datasheet's Typical Operating Characteristics show exact mapping per RTH value.

What is the input impedance of MAX3268CUB+T and how should it be driven?

The MAX3268CUB+T presents a 100Ω differential input impedance between IN+ and IN−. It is designed to be driven directly by transimpedance amplifiers such as the MAX3266 or MAX3267. DC coupling is not recommended - AC coupling with ≥0.01µF capacitors preserves offset correction loop functionality and minimizes deterministic jitter.

MAX3268CUB+T Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc./Maxim Integrated

Series:: -

Package/Case:: 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Type:: Limiting Amplifier

Applications:: Optical Networks

Mounting Type:: Surface Mount

Grade:: -

Qualification:: -

Supplier Device Package:: 10-uMAX-EP

MAX3268CUB+T FAQ

1.How can I place an order for MAX3268CUB+T through Aetrix?

Please submit a Request for Quotation (RFQ) for MAX3268CUB+T 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 MAX3268CUB+T reliable?

The price and inventory of MAX3268CUB+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX3268CUB+T is usually 5 days.

3.What payment methods are accepted for MAX3268CUB+T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX3268CUB+T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MAX3268CUB+T?

MAX3268CUB+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MAX3268CUB+T 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 MAX3268CUB+T?

For technical support, including MAX3268CUB+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX3268CUB+T requirements.

6.How does Aetrix verify that MAX3268CUB+T is sourced from the original manufacturer or authorized distributors?

All MAX3268CUB+T 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 MAX3268CUB+T meets industry standards.

7.What is the process for return or replacement of MAX3268CUB+T?

All MAX3268CUB+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX3268CUB+T, 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 MAX3268CUB+T part is unused and in its original packaging.

Return procedure for MAX3268CUB+T:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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