STMicroelectronics LNBK20PD

Overview

LNBK20PD from STMicroelectronics is a monolithic linear LNB supply and control voltage regulator in PowerSO-20 package, designed for dual-port satellite receivers. It delivers selectable 13 V or 18 V (typ.) regulated outputs to LNBA/LNBB ports, integrates a factory-trimmed 22 kHz tone oscillator (±2 kHz tolerance), supports DiSEqC™ encoding via fast tone enable, and provides dynamic short-circuit protection with 4.7 µF CEXT-based 1200 ms overload cycle - used in analog/digital satellite receiver front-ends.

For engineers reviewing the LNBK20PD datasheet, LNBK20PD pinout, LNBK20PD application, or LNBK20PD equivalent, key selection criteria include dual-output voltage selection logic (VSEL/LLC), stand-by backward current limit (≤3 mA), bypass switch operation (MI→LNBA when EN=L), thermal shutdown at 150 °C, and dual-supply input architecture (VCC1/VCC2) for optimized dissipation.

Technical Context

The LNBK20PD implements a dual-channel linear regulator with logic-controlled output port selection (OSEL), voltage selection (VSEL), and line-length compensation (LLC) to adjust output by +1 V. Its internal 22 kHz oscillator enables DiSEqC™ burst coding with ≤15 µs rise/fall time and 40–60% duty cycle.

Overcurrent protection operates dynamically: upon fault detection, it disables the affected output for t_OFF (set by CEXT), then resumes briefly for t_ON = t_OFF/15 before rechecking - enabling robust start-up into capacitive LNB loads while limiting average power dissipation during sustained shorts.

Key Specifications

Pinout & Package

Supplied in PowerSO-20 surface-mount package (16.0 × 14.5 × 3.6 mm, ECOPACK® lead-free), thermally enhanced with low R_thJC = 2 °C/W for high-power LNB supply applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LNBK20PD, LNBP20D2-TR offers higher current headroom and ruggedness but demands revised thermal management, while LNBH20PD trades linear simplicity for switching efficiency and removes integrated DiSEqC™ support - making LNBK20PD optimal for cost-sensitive, thermally tolerant satellite receivers needing full protocol integration.

Availability

LNBK20PD is available at Aetrix Electronics and suitable for satellite receiver front-ends, DiSEqC™-enabled set-top boxes, and multi-LNB distribution systems requiring stable component supply across extended production lifecycles.

Supply support for LNBK20PD 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and consumer ICs with emphasis on power management and analog interface solutions.

The LNBK20PD belongs to ST's LNBP family of LNB power controllers, engineered specifically for satellite receiver manufacturers needing integrated voltage regulation, DiSEqC™ tone generation, and robust fault protection in compact packages.

FAQ

What is the maximum allowable coaxial cable length supported by the LNBK20PD's line-length compensation?

The LLC pin enables +1 V output boost to compensate for voltage drop across coaxial cable. With typical RG-6U cable (≈0.1 Ω/m), this supports up to ~100 m at 400 mA load before reaching LNB minimum input voltage (typically 11 V). Actual reach depends on cable gauge, ambient temperature, and LNB quiescent current - verified via measurement under worst-case load conditions.

Can the LNBK20PD operate with only one supply input connected?

Yes - VCC1 alone can power both 13 V and 18 V outputs if ≥23 V is applied, though efficiency drops and thermal stress increases at 18 V due to higher dropout. VCC2-only operation is not recommended: VCC1 is required for 13/14 V modes and internal bias. Dual-supply use remains optimal for thermal performance and regulation stability.

How does the OLF pin behave during simultaneous overcurrent on both LNBA and LNBB?

The OLF pin goes LOW whenever either LNBA or LNBB experiences overcurrent or thermal overload - it is not channel-specific. The pin remains LOW for the full t_OFF duration (e.g., 1200 ms with 4.7 µF), then cycles to HIGH-Z for t_ON (80 ms) regardless of which output triggered the fault. Continuous LOW indicates persistent fault on at least one channel.

Is external decoupling required on the EXTM pin when unused?

No - the datasheet explicitly states the EXTM pin may be left open when external modulation is not used. No pull-up, pull-down, or capacitor is needed. However, if routing near noisy signals, a 100 pF capacitor to ground may reduce coupling; this is optional and not specified in the electrical characteristics.