Texas Instruments ONET3301PARGTT

Overview

ONET3301PARGTT from Texas Instruments is a 3.3-Gbps high-speed limiting amplifier with integrated loss-of-signal (LOS) detection and received signal strength indicator (RSSI), delivering 50 dB gain, 3 mV_p−p input sensitivity, and CML differential outputs in a 3 mm × 3 mm QFN package. It operates from a single 3.3-V supply and supports SONET OC48, Fibre Channel 2.125 Gbps, and Gigabit Ethernet receivers.

For engineers reviewing the ONET3301PARGTT datasheet, ONET3301PARGTT pinout, ONET3301PARGTT application, or ONET3301PARGTT equivalent, key selection criteria include input dynamic range (3–1200 mV_p−p), deterministic jitter (≤30 ps_p−p at 2.7 Gbps), RSSI linearity (±3% at 20-dB input), and LOS threshold programmability via external resistor.

Technical Context

The ONET3301PARGTT implements a three-stage high-speed data path with on-chip 50-Ω input termination to VCC and 50-Ω CML output back-termination to VCCO, enabling full differential swing across its 155 Mbps–3.3 Gbps multi-rate operation. Its offset cancellation loop-tunable via COC1/COC2 pins-supports low-frequency cutoffs down to 0.8 kHz with external capacitor.

LOS detection uses a user-programmable threshold (2–40 mV_p−p) referenced to TH pin, while RSSI provides analog voltage proportional to input amplitude (100–2800 mV over 2–80 mV_p−p input). The device integrates bandgap-based bias generation and operates across –40°C to 85°C with <106-mW typical power dissipation.

Key Specifications

Pinout & Package

The ONET3301PARGTT 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 top-left, marked by dot; pin numbering proceeds counterclockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX3748AETE+ and SY88303BLMG, the ONET3301PARGTT uniquely combines programmable LOS, integrated RSSI, and 3–1200 mV_p−p input range in a single 3.3-Gbps solution - reducing BOM count and enabling intelligent optical diagnostics in compact form factors.

Availability

ONET3301PARGTT is available at Aetrix Electronics and suitable for SONET/SDH OC48 systems, Fibre Channel SAN infrastructure, and Gigabit Ethernet optical interfaces requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for ONET3301PARGTT 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, with decades of heritage in high-speed optical networking ICs.

The ONET3301PARGTT belongs to TI's ONET family of optical limiting amplifiers, engineered specifically for multi-rate fiber receiver front-ends in telecom, datacom, and storage applications where low jitter, high dynamic range, and integrated diagnostics are essential.

FAQ

What is the minimum input signal level that the ONET3301PARGTT can reliably detect?

The ONET3301PARGTT achieves a minimum input sensitivity of 3 mV_p−p at BER <10⁻¹⁰, verified under recommended operating conditions (VCC = 3.3 V, TA = 25°C). This performance enables detection of weak signals after low-gain transimpedance amplifiers in long-haul optical links. The ONET3301PARGTT maintains this sensitivity across its full temperature range (–40°C to 85°C) due to on-chip offset cancellation and stable biasing.

How does the RSSI output of the ONET3301PARGTT scale with input amplitude?

The RSSI output of the ONET3301PARGTT provides an analog voltage linearly proportional to input amplitude: 100 mV at 2 mV_p−p input and 2800 mV at 80 mV_p−p input, with ±3% linearity over a 20-dB range. This scaling is internally calibrated and independent of supply voltage variations within 3.0–3.6 V. The ONET3301PARGTT RSSI output drives loads ≥10 kΩ and requires no external buffering for direct connection to ADC inputs or comparator thresholds.

Can the ONET3301PARGTT be used with a 2.5-V supply instead of 3.3 V?

No - the ONET3301PARGTT is specified only for 3.3-V ±10% operation (3.0–3.6 V). Absolute maximum ratings limit VCC/VCCO to 4.0 V, and recommended operating conditions require minimum 3.0 V. Operation below 3.0 V risks failure to meet gain, jitter, and LOS/RSSI specifications. The ONET3301PARGTT contains bandgap-based bias circuitry optimized for 3.3-V rails and does not support dual-supply or lower-voltage configurations.

What is the function of the COC1 and COC2 pins on the ONET3301PARGTT?

The COC1 and COC2 pins on the ONET3301PARGTT 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 baseline stability for low-data-rate protocols like 155 Mbps SONET OC3. Leaving COC1 and COC2 unconnected maintains the default bandwidth; shorting them disables the loop entirely. The ONET3301PARGTT datasheet specifies exact capacitor values and layout guidelines for optimal performance.

Does the ONET3301PARGTT support both AC-coupled and DC-coupled input configurations?

The ONET3301PARGTT is designed for AC-coupled differential inputs only, as confirmed by its internal 50-Ω termination to VCC and absence of DC bias control circuitry. DC-coupled operation is not supported and may violate absolute maximum ratings (e.g., VIN > 4 V). Application Figure 3 in the ONET3301PARGTT datasheet explicitly shows AC-coupling capacitors C1/C2 on the DIN+/DIN− path. For DC-coupled front-ends, alternative amplifiers with adjustable input common-mode voltage are required.