Renesas ISL6423BERZ-T

Overview

ISL6423BERZ-T from Renesas Electronics (formerly Intersil) is a single-output LNB supply and control voltage regulator with integrated I²C interface, boost PWM, low-noise linear regulator, 22kHz tone oscillator, DiSEqC decoder, and fault diagnostics - designed for satellite set-top box antenna port power delivery. It delivers up to 750mA continuous output at selectable 13.3V/14.3V/18.3V/19.3V, supports cable length compensation, and enables polarization switching via SELVTOP pin in 1-tuner/1-dish systems.

For engineers reviewing the ISL6423BERZ-T datasheet, ISL6423BERZ-T pinout, ISL6423BERZ-T application, or ISL6423BERZ-T equivalent, this device serves as a complete LNB power and control solution requiring no external tone generator, minimal passive components, and full I²C-configurable voltage selection, current limiting, and fault reporting - critical for STB design validation, DiSEqC protocol compliance, and thermal-safe LNB interfacing.

Technical Context

The ISL6423BERZ-T integrates a current-mode boost PWM (≥92% efficiency) feeding a low-dropout linear regulator, enabling stable LNB output while maintaining constant ~0.8V dropout across the pass element for tone injection headroom. Its internal 22kHz oscillator is factory-trimmed per EUTELSAT DiSEqC standards and supports both internal tone modulation (via ENT bit) and external DiSEqC envelope injection (via EXTM pin).

I²C control spans eight system registers (SR1–SR4), providing read-back diagnostic flags (OTF, OLF, BCF, CABF), programmable overcurrent thresholds (four levels), dynamic/static current limiting modes (DCL bit), and dual-voltage-range selection (13–14V or 18–19V) via VTOP/VBOT bits or hardware SELVTOP pin - all operating at up to 400kHz I²C fast-mode with 2.5V/3.3V/5V logic compatibility.

Key Specifications

Pinout & Package

ISL6423BERZ-T is packaged in a Pb-free 24-lead 4×4mm QFN (L24.4x4D) with exposed thermal pad. Pin functions are validated per FN6412 Rev 1.00 datasheet, Page 8 (Functional Pin Description) and Page 2 (QFN top view).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LNB supply and control applications.

Compared with MAX2223ETE+ and LM48001QMH/NOPB, the ISL6423BERZ-T uniquely combines full DiSEqC 1.x transmit/receive capability, four-programmable current limits, and hardware SELVTOP pin control - making it the only option that satisfies complete LNB power, polarization switching, and protocol-compliant diagnostics in a single chip for consumer STB designs.

Availability

ISL6423BERZ-T is available at Aetrix Electronics and suitable for satellite set-top box manufacturing, personal video recorder (PVR) development, and digital TV tuner module production requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for ISL6423BERZ-T 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, formed from the merger of NEC Electronics and Renesas Technology, is a global semiconductor leader specializing in microcontrollers, analog, and power management ICs for industrial, automotive, and consumer applications.

The ISL6423BERZ-T belongs to Renesas' legacy Intersil satellite power management product line, engineered specifically for high-efficiency, low-noise LNB supply and DiSEqC control in cost-sensitive, space-constrained STB platforms.

FAQ

What output voltages does the ISL6423BERZ-T support, and how are they selected?

The ISL6423BERZ-T supports four precise output voltages: 13.3V, 14.3V, 18.3V, and 19.3V. Selection is achieved either via I²C register bits VTOP and VBOT (when VSPEN = 1) or through the hardware SELVTOP pin combined with VBOT/VTOP bits (when VSPEN = 0). This dual-mode control allows firmware-based voltage switching or pin-strapped configuration for fixed-polarity LNBs - ensuring compatibility with universal LNBs requiring 13V/18V for vertical/horizontal polarization.

How does the ISL6423BERZ-T implement DiSEqC 1.x communication?

The ISL6423BERZ-T implements DiSEqC 1.x via its EXTM pin for tone modulation and TDIN/TDOUT pins for tone detection. When MSEL = 1 and ENT = 0, EXTM accepts external DiSEqC envelopes and injects them symmetrically onto VO. Simultaneously, TDIN monitors VO for incoming 22kHz tones, and TDOUT asserts low upon detection - enabling full bidirectional DiSEqC protocol handling without external comparators or logic. The internal 22kHz oscillator is factory-trimmed to ±2kHz accuracy per EUTELSAT spec.

What thermal protection features does the ISL6423BERZ-T include?

The ISL6423BERZ-T incorporates junction-temperature sensing with shutdown at 150°C (typ) and automatic recovery at 130°C (typ), plus a latched-off mode after four consecutive overtemperature events. The FLT pin asserts low during thermal fault, and the OTF bit in SR1 register provides persistent status. This multi-tiered protection prevents thermal runaway in enclosed STB chassis while enabling firmware-triggered reset via I²C EN bit toggling - eliminating need for external thermal sensors or reset ICs.

Can the ISL6423BERZ-T drive high-capacitance LNB cables, and what is its maximum load capacitance?

Yes, the ISL6423BERZ-T is designed to drive capacitive LNB loads up to 0.75µF, typical for long coaxial runs. Its linear regulator architecture provides controlled slew rate via the TCAP pin (0.1µF typical), limiting inrush current and preventing instability. The device maintains regulation under full 750mA load even with 0.75µF output capacitance, and includes cable fault detection (CABF flag) to distinguish open-cable (Io < 2mA) from short-circuit (Io > 20mA) conditions - critical for field-installation diagnostics.

What I²C address does the ISL6423BERZ-T use, and is it configurable?

The ISL6423BERZ-T uses a fixed 7-bit I²C slave address of 000100XX (0x10–0x13), where the two LSBs are determined by ADDR0 and ADDR1 pin states (low = 0, high = 1). This allows up to four ISL6423BERZ-T devices on the same bus - useful in multi-tuner STBs. The address is hardware-configurable only; no software register modifies it. All communication follows Philips I²C Specification Rev. 2.1, supporting standard (100kHz) and fast-mode (400kHz) speeds with 2.5V/3.3V/5V logic level compatibility.