Allegro MicroSystems A8282SLBTR

Overview

A8282SLBTR from Allegro MicroSystems is a monolithic LNB supply and control-voltage regulator IC designed for satellite receiver systems. It delivers programmable 12–21 V output to low-noise block downconverters (LNBs) via coaxial cable, integrates a factory-trimmed 22-kHz tone oscillator for DiSEqC™ encoding, and features cable-length compensation (LLC), reverse-current protection, and thermal shutdown. Used in analog/digital satellite receivers requiring stable, low-noise DC power over long coax runs.

For engineers reviewing the A8282SLBTR datasheet, A8282SLBTR pinout, A8282SLBTR application, or A8282SLBTR equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternatives with functional distinctions, and supply-chain support details specific to satellite LNB power management.

Technical Context

The A8282SLBTR combines a current-mode buck converter (352 kHz switching frequency, 16× tone frequency) with a tracking linear regulator to minimize power dissipation across its 12–21 V output range. The buck stage supplies the linear regulator with VBULK voltage dynamically adjusted to maintain ~900 mV headroom above VLNB, enabling efficient tone injection and load regulation.

It supports four discrete output voltages (12/13/18/20 V) via dual VSEL logic inputs and adds ±1 V cable-drop compensation via LLC input. Internal short-circuit protection uses an external sense resistor (RS) referenced to a 135 mV threshold, while OLF provides open-drain fault signaling for overload or thermal shutdown events.

Key Specifications

Pinout & Package

Package: 24-pin SOICW (wide-body), Pb-free matte tin leadframe plating, internally fused ground leads (pins 6, 7, 18, 19) for enhanced thermal dissipation (R_θJA = 35°C/W on JEDEC high-K board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX22026ATJ+T and STV1282A, the A8282SLBTR provides broader voltage flexibility (12–21 V), active cable compensation (LLC), and comprehensive diagnostics (OLF), making it suitable for next-generation multi-standard satellite receivers requiring field-programmable LNB bias and robust fault handling.

Availability

A8282SLBTR is available at Aetrix Electronics and suitable for digital satellite receivers, multi-LNB switching systems, and DirecTV®-compliant terminals requiring stable component supply, long-term lifecycle support, and traceable sourcing for broadcast equipment manufacturing.

Supply support for A8282SLBTR 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

Allegro MicroSystems is a U.S.-based designer and manufacturer of high-performance magnetic sensing and power ICs, serving automotive, industrial, and communications markets since 1989.

The A8282SLBTR belongs to Allegro's LNB supply and control-voltage regulator product line, engineered specifically for satellite receiver power management with integrated DiSEqC™ tone generation, cable-drop compensation, and thermal-safe operation.

FAQ

What output voltages does the A8282SLBTR support, and how are they selected?

The A8282SLBTR supports four discrete output voltages: 12 V, 13 V, 18 V, and 20 V, selected via the logic states of VSEL0 and VSEL1 pins. An additional +1 V boost is enabled by asserting the LLC pin high, yielding 14 V, 19 V, 21 V, or 13 V depending on base selection. This binary-select + compensation scheme meets regional LNB standards including EUTELSAT and DirecTV® specifications without external DACs or resistive dividers.

How does the A8282SLBTR implement DiSEqC™-compliant 22-kHz tone generation?

The A8282SLBTR integrates a factory-trimmed 22-kHz oscillator that produces a trapezoidal waveform with 40–60% duty cycle and 400–900 mV_PP amplitude at the LNB output. Activation is controlled by the ENT pin, and the tone is injected directly into the regulated DC output. No external crystal or timing components are needed, and burst coding is supported due to fast ENT response (<10 µs), enabling full DiSEqC™ 1.0/1.1/1.2 protocol implementation.

What is the purpose of the VINT pin on the A8282SLBTR, and what capacitor value is recommended?

The VINT pin on the A8282SLBTR provides access to an internal 5 V reference used by the VSEL/LLC logic comparators and TCAP timing network. It must be bypassed with a 1–10 µF capacitor (tantalum or ceramic) placed adjacent to the pin. This stabilization prevents logic misstates during voltage transients and ensures accurate slew-rate control and voltage selection-omitting or undersizing this capacitor risks erratic VSEL interpretation or unstable TCAP timing.

Can the A8282SLBTR be used in multi-receiver coaxial sharing applications, and how is reverse current limited?

Yes-the A8282SLBTR supports multi-receiver coaxial sharing via its EN pin. When EN is driven low, the LNB output is disabled and reverse current is actively limited to 1–5 mA (typ. 1 mA) even if VLNB = 22 V and VIN is floating or at 22 V. This prevents backfeeding between receivers on the same coax line, eliminating cross-talk and ensuring safe hot-plug operation without external blocking diodes or complex sequencing.

What thermal performance can be expected from the A8282SLBTR in a standard PCB layout?

On a JEDEC-compliant "high-K" four-layer board, the A8282SLBTR exhibits a junction-to-ambient thermal resistance (R_θJA) of 35°C/W. With a 750 mA load at 18 V output and 24 V input, total power dissipation is ~1.8 W; this yields a junction temperature rise of ~63°C above ambient. Using the fused ground leads (pins 6, 7, 18, 19) with ≥3 in² copper per side reduces thermal impedance further, enabling reliable operation up to +85°C ambient without forced air cooling.