Texas Instruments TPS65235-1RUKR

Overview

TPS65235-1RUKR from Texas Instruments is a monolithic LNB voltage regulator with integrated I²C interface, boost converter, low-dropout linear regulator, and 22-kHz tone generator - designed to supply 13-V to 18-V power and superimposed DiSEqC-compliant tone signals to satellite LNBs. It delivers up to 1000-mA output current with ±10% accuracy via external ISET resistor, supports DiSEqC 2.x/1.x, and operates at selectable 1-MHz or 500-kHz switching frequency in a 3-mm × 3-mm WQFN package.

For engineers reviewing the TPS65235-1RUKR datasheet, TPS65235-1RUKR pinout, TPS65235-1RUKR application, or TPS65235-1RUKR equivalent, key selection considerations include its dual-tone capability (22-kHz/44-kHz), programmable soft-start transition time (2 ms typical), thermal shutdown at 160°C, DiSEqC-compliant GDR gate drive for external MOSFET, and I²C-accessible diagnostics for VLNB voltage, cable connection, and tone status.

Technical Context

The TPS65235-1RUKR integrates a current-mode boost converter with 140-mΩ internal low-side MOSFET and a push-pull LDO stage enabling clean 22-kHz tone superposition even at zero load. Its tone generation supports both internal oscillator and external 22-kHz/44-kHz input via EXTM pin, with amplitude selectable between 650 mV and 750 mV.

DiSEqC 2.x compliance is implemented through dedicated DIN/DOUT tone detection circuitry and GDR-controlled external NMOS switch, while I²C registers (address 0x11 default) provide real-time readback of PGOOD, overcurrent, thermal warning (125°C), and fault flags - all accessible with EN pin held low.

Key Specifications

Pinout & Package

TPS65235-1RUKR is housed in a thermally enhanced 20-pin WQFN package (RUK), 3.0 mm × 3.0 mm, with exposed thermal pad requiring PCB soldering and thermal vias for optimal junction-to-board thermal resistance (R_θJB = 16.5°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LNB power regulation applications.

Compared with TPS65235RUKR and MAX2102ETL+, the TPS65235-1RUKR uniquely integrates DiSEqC 2.x GDR drive, programmable tone amplitude, and I²C-accessible cable diagnostics - enabling single-chip compliance with EN 50494/50600 while reducing layout complexity and test overhead in new satellite receiver designs.

Availability

TPS65235-1RUKR is available at Aetrix Electronics and suitable for satellite TV receivers, set-top box LNB power supplies, and PC card satellite tuners requiring stable component supply, DiSEqC 2.x compliance, and thermal robustness up to 125°C ambient.

Supply support for TPS65235-1RUKR 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 power management technologies, with decades of heritage in satellite and broadcast infrastructure ICs.

The TPS65235-1RUKR belongs to TI's LNB power management product line, engineered specifically for DiSEqC-compliant satellite receiver systems - balancing high efficiency, tone fidelity, diagnostic visibility, and compact packaging for next-generation broadcast equipment.

FAQ

What is the maximum output current accuracy of the TPS65235-1RUKR?

The TPS65235-1RUKR achieves ±10% output current limit accuracy across temperature and process variation when configured with an external ISET resistor. For example, a 200-kΩ resistor sets the nominal current limit to 650 mA, with actual performance ranging from 580 mA to 720 mA per datasheet specifications under full operating conditions. This accuracy is maintained without calibration and directly supports cable-loss compensation in long LNB runs.

How does the TPS65235-1RUKR support DiSEqC 2.x communication?

The TPS65235-1RUKR supports DiSEqC 2.x through three integrated functions: (1) GDR pin drives an external NMOS FET to transmit DiSEqC commands, (2) DIN/DOUT pins detect and relay tone presence for bidirectional handshaking, and (3) I²C registers provide real-time status of tone detection, cable connection, and fault conditions. Unlike DiSEqC 1.x-only alternatives, it enables positioner control and multi-switch addressing without external logic.

Can the TPS65235-1RUKR generate a 44-kHz tone signal?

Yes - the TPS65235-1RUKR supports 44-kHz tone generation when a 44-kHz signal is applied to the EXTM pin and the EXTM TONE bit (Control Register 1, bit 6) is set to 1b. The internal tone generator remains disabled in this mode, and the 44-kHz input is passed directly to the VLNB output with amplitude matching the selected TONEAMP setting (650 mV or 750 mV). This capability is explicitly verified in the Electrical Characteristics table.

What is the purpose of the TCAP pin on the TPS65235-1RUKR?

The TCAP pin on the TPS65235-1RUKR sets the 13-V to 18-V output voltage transition time using an external capacitor (e.g., 22 nF yields ~2 ms). This controlled slew rate prevents instability in the boost converter feedback loop during voltage changes and ensures the LDO reference tracks smoothly. In light-load transitions, an internal pull-down circuit activates to maintain waveform fidelity - a feature critical for avoiding false DiSEqC command rejection.

Does the TPS65235-1RUKR require external components for basic operation?

Yes - the TPS65235-1RUKR requires six minimum external components for functional operation: (1) input capacitor (100 nF), (2) boost inductor (4.7 µH), (3) boost output capacitor (2 × 22 µF), (4) TCAP capacitor (22 nF), (5) ISET resistor (e.g., 200 kΩ), and (6) VCP capacitor (100 nF). Additional components like VCC decoupling (1 µF) and thermal vias for the exposed pad are mandatory for reliability and thermal performance per datasheet guidelines.