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Texas Instruments ONET2501PARGTT
- Part No.:
- ONET2501PARGTT
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 16-VFQFN Exposed Pad
- Datasheet:
-
ONET2501PARGTT.pdf
- Description:
- IC LIMITING 1 CIRCUIT 16VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,000
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Product details
Overview
ONET2501PARGTT from Texas Instruments is a 2.5-Gbps high-speed limiting amplifier with integrated loss-of-signal (LOS) detection and receive signal strength indicator (RSSI), designed for fiber-optic receiver front-ends in SONET/SDH, Fibre Channel, and Gigabit Ethernet systems. It delivers 50 dB gain, supports input dynamic range from 3 mVp−p to 1200 mVp−p, operates on a single 3.3-V supply, and uses a 3 mm × 3 mm 16-pin QFN package.
For engineers reviewing the ONET2501PARGTT datasheet, ONET2501PARGTT pinout, ONET2501PARGTT application, or ONET2501PARGTT equivalent, key selection criteria include differential CML output swing (600–1200 mVp−p), input sensitivity (≤5 mVp−p at BER < 10−10), LOS threshold programmability (2–40 mVp−p), RSSI linearity (≤8%), and −40°C to 85°C industrial temperature operation.
Technical Context
The ONET2501PARGTT implements a three-stage high-speed analog data path with on-chip 50-Ω input termination to VCC and 50-Ω CML output back-termination to VCCO. Its offset cancellation loop-tunable via COC1/COC2 pins-enables stable operation down to 45 kHz low-frequency cutoff (extendable to 0.8 kHz with external capacitor).
LOS detection compares input amplitude against a resistor-programmed threshold at TH pin, with 2.5–4.5 dB hysteresis; RSSI provides a linear analog voltage (100–2800 mV) proportional to input swing (2–80 mVp−p). The device integrates bandgap-based bias generation and requires no external reference.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Data rate | Up to 2.5 Gbps - supports OC48, 2.125-Gbps Fibre Channel, and Gigabit Ethernet physical layer timing. |
| Input sensitivity | 3–5 mVp−p (BER < 10−10) - enables reliable detection of weak optical signals after photodiode amplification. |
| Differential output swing | 600–1200 mVp−p - meets CML interface requirements for downstream clock/data recovery ICs. |
| LOS threshold range | 2–40 mVp−p - adjustable via external resistor on TH pin for system-specific signal loss margining. |
| RSSI output linearity | ≤8% error over 20-dB input range - allows accurate real-time monitoring of received optical power level. |
| Supply current | 32–40 mA at 3.3 V - enables low-power front-end design without compromising high-speed performance. |
| Junction temperature range | −40°C to 85°C - qualified for industrial-grade optical line card and embedded telecom equipment. |
Pinout & Package
ONET2501PARGTT is housed in a 3 mm × 3 mm, 16-pin QFN package with 0.5-mm pitch and exposed thermal pad (EP) connected to GND. Pin 1 is located at top-left corner adjacent to marking dot.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (pins 1, 4) | Supply input | 3.3-V ±10% main supply for input stage and bias circuitry; must be decoupled locally. |
| DIN+, DIN− (pins 2, 3) | Differential analog input | AC-coupled high-speed data inputs with internal 50-Ω termination to VCC; accepts 3–1200 mVp−p swing. |
| TH (pin 5) | Analog input | Connects external resistor to GND to set LOS detection threshold between 2–40 mVp−p. |
| DISABLE (pin 6) | CMOS control input | Active-high signal disables CML output stage within 20 ns; reduces power during idle or fault conditions. |
| LOS (pin 7) | CMOS output | Open-drain output asserts high when input falls below programmed threshold; 2.4-V min high-level at –30 µA. |
| GND (pins 8, 16, EP) | Reference ground | All circuit grounds including exposed thermal pad; EP must be soldered to PCB ground plane for thermal and EMI control. |
| OUTPOL (pin 9) | CMOS control input | Selects output polarity: open/high = normal (DOUT+ in-phase with DIN+); low = inverted. |
| DOUT−, DOUT+ (pins 10, 11) | Differential CML output | 50-Ω back-terminated outputs driving downstream CDR or FPGA transceivers; swing 600–1200 mVp−p. |
| VCCO (pin 12) | Supply input | 3.3-V ±10% dedicated supply for CML output stage; separate from VCC to isolate noise coupling. |
| RSSI (pin 13) | Analog output | Voltage proportional to log-scale input amplitude (100–2800 mV for 2–80 mVp−p); used for AGC or diagnostics. |
| COC1, COC2 (pins 14, 15) | Analog filter terminals | Connect external capacitor (e.g., 2.2 nF) between them to extend offset cancellation loop bandwidth down to 0.8 kHz. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated RSSI and LOS detection | Eliminates need for external monitoring circuitry; RSSI provides analog feedback for automatic gain control loops. |
| Programmable LOS threshold | Resistor-adjustable trigger point (2–40 mVp−p) enables system-specific loss margining without firmware changes. |
| Output polarity select and disable | Hardware-configurable DOUT+/DOUT− inversion and fast (<20 ns) output shutdown support protocol-level link management. |
| On-chip 50-Ω terminations | Reduces BOM count and layout complexity by integrating input termination to VCC and output back-termination to VCCO. |
| Offset cancellation with external tuning | Stabilizes DC operating point across temperature and process variation; COC1/COC2 allow cutoff frequency adjustment from 45 kHz to 0.8 kHz. |
Applications
| SONET/SDH OC48 Receivers | Fibre Channel 2.125-Gbps Receivers |
|---|---|
|
Use Scenario: Front-end amplification in OC48 (2.488-Gbps) line cards for metro and access networks. IC Role / Device Role / Timing Role: Limiting amplifier conditioning photodiode output before CDR; provides deterministic jitter <30 psp−p at 2.5 Gbps. Use Value: Enables robust signal recovery under varying optical power (−30 to −3 dBm) while maintaining BER < 10−12. |
Use Scenario: Signal conditioning in storage area network (SAN) host bus adapters and switch ports. IC Role / Device Role / Timing Role: High-gain limiting stage converting low-amplitude differential signals from VCSELs into clean CML logic levels. Use Value: Supports hot-plug detection via RSSI and link integrity monitoring via LOS, reducing firmware overhead. |
| Gigabit Ethernet PHY Receivers | Optical Transceiver Modules (SFP) |
|
Use Scenario: 1.25-Gbps receiver path in enterprise switches and routers compliant with IEEE 802.3z. IC Role / Device Role / Timing Role: Amplifies degraded signals from multimode fiber links; compensates for modal dispersion-induced jitter. Use Value: Input overload tolerance up to 1200 mVp−p prevents saturation during burst-mode traffic or reflectance events. |
Use Scenario: Embedded in SFP modules for telecom and datacom applications requiring compact, low-power front-end amplification. IC Role / Device Role / Timing Role: Core limiting amplifier in pluggable optics; interfaces directly with laser driver and CDR ASICs. Use Value: 3 mm × 3 mm QFN footprint saves board space; single 3.3-V supply simplifies module power architecture. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar limiting amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX3748AETE+ | Higher max data rate (3.2 Gbps); RSSI output not available; requires dual supplies (3.3 V + 2.5 V). | Better suited for 10G-EPON or CPRI front-ends where extended bandwidth is critical; lacks integrated RSSI for diagnostics. | Choose MAX3748AETE+ when >2.5 Gbps operation or lower deterministic jitter (<15 psp−p) is required; avoid if RSSI or single-supply simplicity is mandatory. |
| LMH6522MA/NOPB | Wider bandwidth (DC to 3.5 GHz); no built-in LOS/RSSI; higher supply current (65 mA); SOIC-8 package. | Used in RF sampling and wideband test equipment; lacks optical-specific features like programmable LOS threshold. | Choose LMH6522MA/NOPB for non-optical, wide-dynamic-range analog signal chains; avoid for standardized optical receiver designs requiring LOS/RSSI compliance. |
Compared with MAX3748AETE+ and LMH6522MA/NOPB, the ONET2501PARGTT uniquely integrates RSSI, programmable LOS, and CML output drive in a single 3.3-V, 16-pin QFN package optimized for 155 Mbps–2.5 Gbps optical standards-offering lowest BOM count and fastest time-to-deploy in SONET, Fibre Channel, and Gigabit Ethernet receivers.
Availability
ONET2501PARGTT is available at Aetrix Electronics and suitable for SONET/SDH transmission systems, Fibre Channel receivers, and Gigabit Ethernet PHY implementations requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for ONET2501PARGTT 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, communications, and consumer markets.
The ONET2501PARGTT belongs to TI's Optical Networking amplifier product line, engineered specifically for high-speed fiber-optic receiver front-ends requiring low jitter, wide input dynamic range, and integrated signal health monitoring.
FAQ
What is the minimum input signal level supported by the ONET2501PARGTT?
The ONET2501PARGTT supports input signals as low as 3 mVp−p while maintaining BER < 10−10, verified per its datasheet's dc electrical characteristics table. This sensitivity enables reliable operation with low-output photodiodes or high-loss fiber links. The device achieves this using a 50-dB gain architecture with precision offset cancellation. Designers should ensure proper AC coupling and impedance matching to preserve signal integrity at this level. The ONET2501PARGTT's performance remains stable across its full −40°C to 85°C operating range.
Does the ONET2501PARGTT require external termination resistors on its differential inputs?
No, the ONET2501PARGTT integrates 50-Ω on-chip termination resistors from DIN+ and DIN− to VCC, eliminating the need for external input termination components. This simplifies PCB layout and reduces BOM cost. However, designers must still provide local 3.3-V decoupling capacitors near VCC/VCCO pins and ensure proper AC coupling (e.g., 100 nF) on both input and output paths as shown in the recommended application circuit. The ONET2501PARGTT's internal termination is optimized for standard 50-Ω differential signaling environments used in optical receivers.
How is the loss-of-signal (LOS) threshold configured on the ONET2501PARGTT?
The LOS threshold on the ONET2501PARGTT is set by connecting an external resistor between the TH pin (pin 5) and GND. The datasheet specifies a programmable range of 2–40 mVp−p, with exact threshold determined by resistor value per TI's application curves. No additional active components are needed. The LOS output (pin 7) is an open-drain CMOS signal that asserts high when input amplitude drops below the programmed threshold, with 2.5–4.5 dB hysteresis to prevent chatter. This configuration is fully hardware-based and requires no firmware or calibration for the ONET2501PARGTT.
Can the ONET2501PARGTT operate with only one supply voltage?
Yes, the ONET2501PARGTT operates from a single 3.3-V ±10% supply, but it requires two distinct supply connections: VCC (pins 1, 4) powers the input stage and bias circuitry, while VCCO (pin 12) powers the CML output stage. Though both accept 3.3 V, separating them improves PSNR (26 dB for f < 2 MHz) and reduces crosstalk between input and output paths. The ONET2501PARGTT's internal bandgap reference ensures stable operation across temperature and supply variation without needing external references or regulators.
What is the purpose of the COC1 and COC2 pins on the ONET2501PARGTT?
The COC1 (pin 14) and COC2 (pin 15) pins on the ONET2501PARGTT provide access to the internal offset cancellation loop filter. Connecting an external capacitor (e.g., 2.2 nF) between them extends the low-frequency −3-dB bandwidth from 45 kHz down to 0.8 kHz, improving stability for very low data rates or burst-mode signals. Leaving them unconnected maintains the default 45-kHz cutoff. Shorting COC1 and COC2 disables the loop entirely. This flexibility allows designers to optimize the ONET2501PARGTT for specific modulation schemes without modifying the core amplifier design.
ONET2501PARGTT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-VFQFN Exposed Pad
- Packaging:
- Bulk
- Product Status:
- Discontinued at Digi-Key
- Amplifier Type:
- Limiting
- Number of Circuits:
- 1
- Output Type:
- Differential
- Slew Rate:
- -
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 45 kHz
- Current - Input Bias:
- -
- Voltage - Input Offset:
- -
- Current - Supply:
- 32mA
- Current - Output / Channel:
- 25 mA
- 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)
ONET2501PARGTT FAQ
1.How can I place an order for ONET2501PARGTT through Aetrix?
Please submit a Request for Quotation (RFQ) for ONET2501PARGTT 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 ONET2501PARGTT reliable?
The price and inventory of ONET2501PARGTT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ONET2501PARGTT is usually 5 days.
3.What payment methods are accepted for ONET2501PARGTT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ONET2501PARGTT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ONET2501PARGTT?
ONET2501PARGTT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ONET2501PARGTT 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 ONET2501PARGTT?
For technical support, including ONET2501PARGTT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ONET2501PARGTT requirements.
6.How does Aetrix verify that ONET2501PARGTT is sourced from the original manufacturer or authorized distributors?
All ONET2501PARGTT 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 ONET2501PARGTT meets industry standards.
7.What is the process for return or replacement of ONET2501PARGTT?
All ONET2501PARGTT units undergo pre-shipment inspection (PSI). If there is an issue with ONET2501PARGTT, 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 ONET2501PARGTT part is unused and in its original packaging.
Return procedure for ONET2501PARGTT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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