Renesas GX36220-F-DNT

Overview

GX36220-F-DNT from Renesas Electronics (formerly IDT) is a dual-channel 64Gbps linear trans-impedance amplifier (TIA) designed for I/Q signal paths in integrated coherent receivers. It delivers 150–5,000Ω differential linear gain, >40 GHz 3dB bandwidth, and >30dB dynamic range, enabling 400G/600G optical links using 16QAM/64QAM modulation in CFP2/CFP4 modules.

For engineers reviewing the GX36220-F-DNT datasheet, GX36220-F-DNT pinout, GX36220-F-DNT application, or GX36220-F-DNT equivalent, key selection criteria include analog-controlled gain range, adjustable bandwidth, AGC/peak detection functionality, output voltage control, and low THD/crosstalk performance for high-order QAM coherent detection.

Technical Context

The GX36220-F-DNT implements two independent TIA signal chains with dedicated VGA1/VGA2 stages, DC offset cancellation loops (Loop1–Loop3), and CM feedback architecture to maintain common-mode stability across high-speed differential outputs. Each channel supports automatic gain control and peak detection for adaptive signal conditioning in real-time coherent demodulation.

Bandwidth is adjustable via external BW control pins, and gain is set through analog GC-Gain Control inputs with 150–5,000Ω range. Output stage includes OA-Output Voltage Control and Output Monitor functionality, enabling closed-loop biasing and system-level signal integrity validation without external instrumentation.

Key Specifications

Pinout & Package

Package: 40-pin QFN (6 mm × 6 mm, 0.4 mm pitch), thermally enhanced, exposed pad.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel high-speed linear TIA applications.

Compared with MAX3748AETE+ and HMC1093LP5E, the GX36220-F-DNT uniquely integrates dual 64Gbps paths with analog-adjustable bandwidth and gain, on-chip AGC/peak detection, and >40 GHz BW-enabling direct support for 600G coherent systems without external signal conditioning.

Availability

GX36220-F-DNT is available at Aetrix Electronics and suitable for 400G/600G coherent transceivers, CFP2/CFP4 optical modules, and metro line card designs requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for GX36220-F-DNT 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

Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog power, and connectivity solutions for automotive, industrial, and data infrastructure markets.

The GX36220-F-DNT belongs to Renesas' high-speed optical interconnect product line, engineered specifically for next-generation coherent receiver front-ends in 400G/600G optical modules and pluggable transceivers.

FAQ

What is the primary function of the GX36220-F-DNT in a coherent optical receiver?

The GX36220-F-DNT serves as a dual-channel linear trans-impedance amplifier that converts weak photocurrents from I/Q balanced photodiodes into amplified, low-distortion differential voltage signals. Its >40 GHz bandwidth and 150–5,000Ω gain range make it essential for preserving signal integrity in 64Gbaud 64QAM coherent detection. The GX36220-F-DNT integrates AGC, peak detection, and output voltage control to simplify front-end design in CFP2/CFP4 modules.

Does the GX36220-F-DNT support both 16QAM and 64QAM modulation formats?

Yes, the GX36220-F-DNT supports both 16QAM and 64QAM modulation formats through its >40 GHz 3dB bandwidth, >30 dB dynamic range, and low THD/crosstalk performance. These specifications ensure sufficient signal-to-noise ratio and linearity for maintaining EVM below 10⁻⁴ in 64QAM operation. The GX36220-F-DNT's analog gain and bandwidth controls allow system-level optimization for either format without hardware change.

How does the analog gain control (GC) interface of the GX36220-F-DNT operate?

The GX36220-F-DNT features dedicated analog GC_I and GC_Q pins that accept voltage inputs to set trans-impedance per channel across a 150–5,000Ω range. This enables precise, continuous gain adjustment without digital registers or SPI communication. The GX36220-F-DNT's GC interface works in conjunction with internal AGC and peak detection to maintain optimal signal swing at the output stage, especially under varying optical input power conditions.

Is the GX36220-F-DNT pin-compatible with earlier IDT TIA devices like the GX36120?

No, the GX36220-F-DNT is not pin-compatible with the GX36120. While both are dual-channel TIAs, the GX36220-F-DNT uses a 40-pin QFN package with distinct pin assignments for BW control, OA output voltage, and separate VCC rails. The GX36120 employs a different pinout and lacks analog bandwidth control and integrated peak detection. Board redesign is required when migrating to the GX36220-F-DNT.

What thermal management considerations apply to the GX36220-F-DNT in CFP2 modules?

The GX36220-F-DNT uses a 6 mm × 6 mm QFN package with an exposed thermal pad requiring solder connection to a solid copper plane for effective heat dissipation. In CFP2 modules, junction temperature must remain below 105°C under full 64Gbps operation. The GX36220-F-DNT's low-power design minimizes thermal load, but airflow and PCB copper area beneath the exposed pad are critical-typical thermal resistance is 22°C/W junction-to-board with 2-in² 2-oz copper.