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Home > Products > Integrated Circuits (ICs) > Linear > Instrumentation, Op Amps, Buffer Amps

Texas Instruments ONET4201PARGTTG4

Name: ONET4201PARGTTG4
Brand: Texas Instruments
SKU: ONET4201PARGTTG4
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ONET4201PARGTTG4

Manufacturer:: Texas Instruments

Category:: Instrumentation, Op Amps, Buffer Amps

Package:: 16-VFQFN Exposed Pad

Datasheet:: ONET4201PARGTTG4.pdf

Description:: IC LIMITING 1 CIRCUIT 16VQFN

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Product details

Overview

ONET4201PARGTTG4 from Texas Instruments is a 3.3-V, 155 Mbps to 4.25 Gbps high-speed limiting amplifier with integrated loss-of-signal (LOS) detection and receive signal strength indicator (RSSI). It delivers ~50 dB gain, supports CML differential outputs, and operates across –40°C to 85°C for fiber optic receiver front-ends in SONET/SDH and Fibre Channel systems.

For engineers reviewing the ONET4201PARGTTG4 datasheet, ONET4201PARGTTG4 pinout, ONET4201PARGTTG4 application, or ONET4201PARGTTG4 equivalent, key selection criteria include input sensitivity (3 mV_p-p), output swing (520–760 mV_p-p), deterministic jitter (≤35 ps_p-p at 2.125 Gbps), RSSI linearity (±3%), and LOS threshold programmability via external resistor.

Technical Context

The ONET4201PARGTTG4 implements a three-stage high-speed data path with on-chip 50-Ω input termination to VCC and CML output stage with 50-Ω back-termination. Offset cancellation ensures stable operation down to 3 mV_p-p inputs, while built-in low-frequency filtering (25 kHz typical cutoff) supports DC-coupled or AC-coupled configurations.

Its LOS and RSSI detection block uses a linear amplitude-to-voltage converter referenced to an internal bandgap, with programmable threshold via TH pin (R_TH = 1.2–6.8 kΩ), enabling precise signal presence monitoring across multi-rate optical links from OC-3 to OC-48 and 1.0625–4.25 Gbps Fibre Channel.

Key Specifications

Parameter	Value and Actual Design Meaning
Data Rate	Up to 4.25 Gbps - supports OC-48, 4× Fibre Channel, and Gigabit Ethernet physical layer receivers.
Input Sensitivity	3 mV_p-p (min) - enables reliable amplification of weak signals from long-haul or attenuated optical paths.
Output Swing	520–760 mV_p-p differential - meets CML logic thresholds for direct interfacing with downstream clock/data recovery (CDR) ICs.
Deterministic Jitter	≤35 ps_p-p at 2.125 Gbps - preserves eye opening in high-speed serial links requiring BER < 10⁻¹⁰.
RSSI Linearity	±3% over 8–80 mV_p-p input - provides accurate analog representation of received optical power for closed-loop link margining.
Power Consumption	35–45 mA at 3.3 V (≈89 mW) - enables dense integration in power-constrained SFP/SFP+ modules and line cards.
Operating Temperature	–40°C to +85°C - qualified for industrial and telecom infrastructure environments without derating.

Pinout & Package

The ONET4201PARGTTG4 is housed in a 3-mm × 3-mm, 16-pin QFN package (RGT) with 0.5-mm pitch and exposed thermal pad (EP) requiring PCB grounding.

Pin/Terminal	Circuit Role	Design Meaning
VCC (Pins 1, 4, 12)	Supply input	3.3-V ±10% primary power rail; three pins reduce IR drop and improve PSRR in high-speed operation.
DIN+, DIN− (Pins 2, 3)	Differential analog input	50-Ω on-chip termination to VCC enables direct AC-coupled connection to photodiode transimpedance amplifier (TIA) outputs.
TH (Pin 5)	Analog input	Connects external resistor to GND to set LOS assert voltage (e.g., 2.5 kΩ → ~10 mV_p-p).
DISABLE (Pin 6)	Digital control input	CMOS-level active-high signal disables CML output stage to suppress radiation during link idle states.
LOS (Pin 7)	Digital status output	CMOS-level open-drain output indicating signal loss when input falls below programmed threshold.
GND (Pins 8, 16, EP)	Reference ground	Low-inductance return path; exposed pad must be soldered to solid ground plane for thermal and noise performance.
OUTPOL (Pin 9)	Digital control input	Selects output polarity inversion; internally pulled high for normal operation (no external pull-up required).
DOUT−, DOUT+ (Pins 10, 11)	Differential CML output	50-Ω on-chip back-termination to VCC allows direct connection to 50-Ω transmission lines without external resistors.
RSSI (Pin 13)	Analog output	Voltage proportional to log-scale input amplitude; used for real-time optical power monitoring and diagnostics.
COC1, COC2 (Pins 14, 15)	Analog filter terminals	Connect external capacitor between pins to extend offset cancellation loop bandwidth below 25 kHz for ultra-low-frequency applications.

Key Features

Feature	Design Value
Multi-rate limiting architecture	Single device supports 155 Mbps to 4.25 Gbps without reconfiguration - eliminates need for multiple SKUs in mixed-speed optical modules.
Integrated RSSI with ±3% linearity	Enables precise optical power calibration and dynamic link budget management without external ADC or scaling circuitry.
Programmable LOS threshold	Adjustable assert/deassert hysteresis (2.5–4.5 dB) via single external resistor - simplifies compliance testing across varying extinction ratios and modal noise conditions.
CML output with polarity select	Eliminates need for external inverters or layout rerouting when matching downstream CDR or FPGA input polarity requirements.
On-chip 50-Ω terminations	Reduces BOM count and board space by removing four external termination resistors per channel in typical TIA-to-limiter interfaces.

Applications

SONET/SDH OC-48 Receivers	Fibre Channel 4× Receivers
Use Scenario: Front-end limiting amplifier in OC-48 (2.488 Gbps) line interface cards for metro and core transport equipment. IC Role / Device Role / Timing Role: Converts low-amplitude, high-jitter TIA output into clean, full-swing CML data for clock/data recovery and descrambling. Use Value: 50 dB gain and 35 ps_p-p deterministic jitter ensure bit-error ratio < 10⁻¹² under worst-case dispersion and PMD conditions.	Use Scenario: Signal conditioning stage in 4× Fibre Channel (4.25 Gbps) host bus adapters and storage switches. IC Role / Device Role / Timing Role: Amplifies degraded signals from multimode fiber links while providing RSSI feedback for automatic gain control (AGC) loop stability. Use Value: RSSI linearity ±3% and programmable LOS enable robust link training and fault isolation across diverse cable lengths and transceiver types.
Gigabit Ethernet Receivers	Optical Transceiver Modules (SFP/SFP+)
Use Scenario: High-sensitivity receiver in enterprise-grade 1000BASE-X PHY implementations operating over single-mode or long-reach multimode fiber. IC Role / Device Role / Timing Role: Limits and reshapes recovered data after TIA, delivering jitter-clean CML output compatible with standard Ethernet MAC interface timing budgets. Use Value: Input sensitivity of 3 mV_p-p extends reach beyond IEEE 802.3z specifications, supporting extended-distance optical links up to 80 km.	Use Scenario: Core limiting amplifier in compact pluggable optical modules where thermal dissipation and footprint are constrained. IC Role / Device Role / Timing Role: Provides gain, signal integrity, and diagnostic functions (RSSI/LOS) within tight mechanical envelope and 89 mW power budget. Use Value: 3-mm × 3-mm QFN package with exposed pad achieves >100°C/W thermal resistance, enabling operation at full data rate in sealed module housings.

SONET/SDH OC-48 Receivers

Fibre Channel 4× Receivers

Use Scenario: Front-end limiting amplifier in OC-48 (2.488 Gbps) line interface cards for metro and core transport equipment.

IC Role / Device Role / Timing Role: Converts low-amplitude, high-jitter TIA output into clean, full-swing CML data for clock/data recovery and descrambling.

Use Value: 50 dB gain and 35 ps_p-p deterministic jitter ensure bit-error ratio < 10⁻¹² under worst-case dispersion and PMD conditions.

Use Scenario: Signal conditioning stage in 4× Fibre Channel (4.25 Gbps) host bus adapters and storage switches.

IC Role / Device Role / Timing Role: Amplifies degraded signals from multimode fiber links while providing RSSI feedback for automatic gain control (AGC) loop stability.

Use Value: RSSI linearity ±3% and programmable LOS enable robust link training and fault isolation across diverse cable lengths and transceiver types.

Gigabit Ethernet Receivers

Optical Transceiver Modules (SFP/SFP+)

Use Scenario: High-sensitivity receiver in enterprise-grade 1000BASE-X PHY implementations operating over single-mode or long-reach multimode fiber.

IC Role / Device Role / Timing Role: Limits and reshapes recovered data after TIA, delivering jitter-clean CML output compatible with standard Ethernet MAC interface timing budgets.

Use Value: Input sensitivity of 3 mV_p-p extends reach beyond IEEE 802.3z specifications, supporting extended-distance optical links up to 80 km.

Use Scenario: Core limiting amplifier in compact pluggable optical modules where thermal dissipation and footprint are constrained.

IC Role / Device Role / Timing Role: Provides gain, signal integrity, and diagnostic functions (RSSI/LOS) within tight mechanical envelope and 89 mW power budget.

Use Value: 3-mm × 3-mm QFN package with exposed pad achieves >100°C/W thermal resistance, enabling operation at full data rate in sealed module housings.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ONET2501PA	Lower max data rate (2.5 Gbps); identical pinout and RSSI/LOS functionality.	Suitable for OC-48 and 2.125 Gbps Fibre Channel only - not rated for 4.25 Gbps operation.	Select when system data rate ceiling is ≤2.5 Gbps and legacy compatibility with ONET4201PARGTTG4 layout is required.
MAX3761	Higher power (120 mW); no integrated RSSI; requires external LOS comparator.	Lacks analog RSSI output and programmable LOS - demands additional components for signal monitoring functions.	Choose when absolute minimum jitter (<25 ps_p-p) is prioritized over power and diagnostic integration, and board area permits discrete support circuitry.

Compared with ONET2501PA and MAX3761, the ONET4201PARGTTG4 uniquely balances 4.25 Gbps capability, integrated diagnostics (RSSI + programmable LOS), and sub-90 mW power in a pin-compatible 3-mm QFN - making it optimal for next-generation SFP+ and OTU2 optical modules requiring both performance and system-level observability.

Availability

ONET4201PARGTTG4 is available at Aetrix Electronics and suitable for SONET/SDH line cards, Fibre Channel storage interconnects, and Gigabit Ethernet optical transceivers requiring stable component supply across extended product lifecycles.

Supply support for ONET4201PARGTTG4 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies for industrial, automotive, and communications markets.

The ONET4201PARGTTG4 belongs to TI's ONET family of high-speed optical receiver ICs, engineered specifically for multi-rate fiber optic communication systems demanding low jitter, high sensitivity, and integrated signal health monitoring.

FAQ

What is the minimum input signal amplitude supported by the ONET4201PARGTTG4?

The ONET4201PARGTTG4 supports a minimum input signal amplitude of 3 mV_p-p at BER < 10⁻¹⁰, enabled by its ~50 dB gain and internal offset cancellation. This allows reliable amplification of weak signals from long-haul optical links or low-output photodiodes. The ONET4201PARGTTG4 maintains this sensitivity across its full 155 Mbps to 4.25 Gbps operating range without configuration changes.

Does the ONET4201PARGTTG4 require external termination resistors on its CML outputs?

No, the ONET4201PARGTTG4 integrates 50-Ω back-termination to VCC on both DOUT+ and DOUT− pins, eliminating the need for external resistors in standard 50-Ω transmission line designs. This reduces component count, PCB area, and potential impedance mismatches. The ONET4201PARGTTG4's internal termination is optimized for stable CML output swing (520–760 mV_p-p) across temperature and process variation.

How is the loss-of-signal (LOS) threshold configured on the ONET4201PARGTTG4?

The LOS threshold on the ONET4201PARGTTG4 is configured using an external resistor (R_TH) connected between the TH pin and GND. R_TH values from 1.2 kΩ to 6.8 kΩ set the assert voltage (V_AST) from ~2 mV_p-p to ~17 mV_p-p. The ONET4201PARGTTG4 datasheet provides equations to calculate V_AST and V_DEA based on R_TH, ensuring precise threshold alignment with system-specific extinction ratio and noise margins.

Can the ONET4201PARGTTG4 operate with AC-coupled inputs and outputs?

Yes, the ONET4201PARGTTG4 supports AC-coupled interfaces on both DIN+/DIN− and DOUT+/DOUT−. Its internal 50-Ω terminations are referenced to VCC, allowing direct connection through series coupling capacitors. The ONET4201PARGTTG4's input common-mode range (0.5 V to 4.0 V) and output compliance accommodate standard AC-coupled layouts used in SFP and XFP modules without level-shifting circuitry.

What is the function of the COC1 and COC2 pins on the ONET4201PARGTTG4?

The COC1 and COC2 pins on the ONET4201PARGTTG4 provide access to the internal offset cancellation loop filter. Connecting an external capacitor (e.g., 0.54 µF) between them lowers the loop's low-frequency cutoff from 25 kHz to ~0.8 kHz, improving baseline stability for very low-frequency or DC-coupled optical signals. Leaving COC1 and COC2 open configures the default 25 kHz cutoff. The ONET4201PARGTTG4 does not require external components for basic operation but offers this flexibility for specialized applications.

ONET4201PARGTTG4 Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: 16-VFQFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Discontinued at Digi-Key

Amplifier Type:: Limiting

Number of Circuits:: 1

Output Type:: Differential

Slew Rate:: -

Gain Bandwidth Product:: -

-3db Bandwidth:: 25 kHz

Current - Input Bias:: -

Voltage - Input Offset:: -

Current - Supply:: 35mA

Current - Output / Channel:: -

Voltage - Supply Span (Min):: 3 V

Voltage - Supply Span (Max):: 3.6 V

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-VQFN (3x3)

ONET4201PARGTTG4 FAQ

1.How can I place an order for ONET4201PARGTTG4 through Aetrix?

Please submit a Request for Quotation (RFQ) for ONET4201PARGTTG4 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 ONET4201PARGTTG4 reliable?

The price and inventory of ONET4201PARGTTG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ONET4201PARGTTG4 is usually 5 days.

3.What payment methods are accepted for ONET4201PARGTTG4?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ONET4201PARGTTG4 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ONET4201PARGTTG4?

ONET4201PARGTTG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ONET4201PARGTTG4 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 ONET4201PARGTTG4?

For technical support, including ONET4201PARGTTG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ONET4201PARGTTG4 requirements.

6.How does Aetrix verify that ONET4201PARGTTG4 is sourced from the original manufacturer or authorized distributors?

All ONET4201PARGTTG4 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 ONET4201PARGTTG4 meets industry standards.

7.What is the process for return or replacement of ONET4201PARGTTG4?

All ONET4201PARGTTG4 units undergo pre-shipment inspection (PSI). If there is an issue with ONET4201PARGTTG4, 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 ONET4201PARGTTG4 part is unused and in its original packaging.

Return procedure for ONET4201PARGTTG4:

1.Submit a request within 90 days.

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

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