Renesas TW3811-TC1-CRT

Overview

TW3811-TC1-CRT from Intersil is a Security Link Over Coax (SLOC) receiver IC that decodes a single coaxial SLOC signal into separate analog CVBS video and 100BASE-T Ethernet digital video data. It integrates an AFE, digital modem, dual MII/RMII interfaces, and proprietary adaptive equalization for CVBS extension up to 500m over RG59 cable. Used in DVR/NVR systems and stand-alone SLOC-to-IP+CVBS converters.

For engineers reviewing the TW3811-TC1-CRT datasheet, TW3811-TC1-CRT pinout, TW3811-TC1-CRT application, or TW3811-TC1-CRT equivalent, key selection criteria include its dual-mode MII/RMII interface configuration, 36Mbps downlink/4Mbps uplink SLOC compliance, integrated PLL with 25MHz crystal support, and CVBS output linearity (≤5% luminance non-linearity) under real coax loading.

Technical Context

The TW3811-TC1-CRT implements a full-duplex SLOC physical layer using proprietary modulation to simultaneously carry IP video and analog CVBS over coax. Its internal architecture includes a band-pass filtered ADC path for CVBS recovery, a DSP-based digital modem for IP packet extraction, and dual configurable Ethernet interfaces (MIIA for MAC emulation, MIIB for PHY emulation).

It supports two operational modes via MODE_S3: Mode A (TW3811 acts as MAC, connects to external PHY) and Mode B (TW3811 acts as PHY, connects to external SoC/MAC). Register-controlled link speed (4Mbps uplink, 36Mbps downlink), Reed-Solomon error correction, and I²C-managed CVBS gain (0x30 register) enable robust deployment in variable-length coax environments.

Key Specifications

Pinout & Package

Package: 100-pin TQFP (12×12 mm, Pb-free, RoHS compliant, Q100.12X12A drawing).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SLOC receiver applications.

Compared with TW3811-TC1-CR (bulk) and TW3811-TC1-CR-EVAL (board), the TW3811-TC1-CRT offers tape-and-reel packaging optimized for automated SMT placement, while retaining identical thermal, electrical, and functional behavior-making it the preferred choice for volume DVR/NVR manufacturing.

Availability

TW3811-TC1-CRT is available at Aetrix Electronics and suitable for security DVR/NVR development, coax-based IP camera backhaul, and analog-to-IP field upgrade programs requiring stable component supply across extended product lifecycles.

Supply support for TW3811-TC1-CRT 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

Intersil (now part of Renesas Electronics) is a semiconductor company specializing in precision analog, power management, and interface ICs for industrial, communications, and security applications.

The TW3811-TC1-CRT belongs to Intersil's SLOC™ transceiver family, engineered specifically to extend IP video capability over legacy coax infrastructure while preserving analog monitoring paths in professional security systems.

FAQ

What is the primary function of the TW3811-TC1-CRT in a SLOC system?

The TW3811-TC1-CRT is the receiver IC in the SLOC™ protocol stack, responsible for decoding a single coaxial SLOC signal into parallel analog CVBS video and 100BASE-T Ethernet digital video data. It performs analog equalization, digital demodulation, Reed-Solomon error correction, and MII/RMII interface bridging-enabling simultaneous analog preview and IP recording from one coax cable. Its operation is fully defined in the FN8284 Rev.1.00 datasheet.

Does the TW3811-TC1-CRT support both MII and RMII interfaces, and how is the mode selected?

Yes, the TW3811-TC1-CRT supports both MII and RMII interfaces. Mode selection is controlled by register 0x01[5] (Interface Selection) and pin LED_0 / MII_Mode_Select (53). When register 0x01[0] = 0, the pin state at power-on determines mode: >2.0V = MII, <0.8V = RMII. When register 0x01[0] = 1, the setting is software-controlled. The TW3811-TC1-CRT has been validated with Marvell 88E1111 and IC+ IP101A PHYs in both modes.

What is the maximum coaxial cable length supported by the TW3811-TC1-CRT, and what conditions ensure compliance?

The TW3811-TC1-CRT supports up to 500m of RG59 coaxial cable when used with the TW3801 transmitter and configured for 4Mbps uplink (register 0x0A = 0x04). This length is SLOC-compliance certified. Using 3Mbps (0x03) is acceptable for marginal installations. Performance depends on proper COAX_IN termination, LOAD_DRV 75Ω resistor placement, and CVBS equalization tuning-details are specified in the FN8284 Rev.1.00 application schematic.

How does the TW3811-TC1-CRT handle CVBS output quality, and what parameters are guaranteed?

The TW3811-TC1-CRT guarantees CVBS output performance under defined test conditions: ≤5% luminance non-linearity, ≤1.8% chroma gain distortion, ≤2° chroma phase distortion, 5.4MHz (−3dB) bandwidth, and 52.5dB SNR (unweighted). These values are measured with 1m RG59 coax, TW3801 input, and standard 5-step/modulated pedestal test patterns-as documented in the FN8284 Rev.1.00 Electrical Specifications table on page 6.

Can the TW3811-TC1-CRT operate without an external crystal, and what are the clock requirements?

No, the TW3811-TC1-CRT requires a 25MHz ±50ppm crystal connected to XTAL_IN (84) and XTAL_OUT (85) pins. The device integrates a PLL but does not support external clock input in lieu of crystal. The crystal must be paired with two 22pF load capacitors and a 1MΩ feedback resistor as shown in the reference schematic (page 2). Omitting the crystal prevents oscillator startup and renders the TW3811-TC1-CRT non-operational.