STMicroelectronics LNBK20PD-TR

Overview

LNBK20PD-TR from STMicroelectronics is a monolithic linear LNB supply and control voltage regulator in PowerSO-20 package, designed for satellite receiver front-ends to deliver regulated 13 V or 18 V (typ.) DC power and 22 kHz tone modulation over coaxial cable to antenna-mounted LNB downconverters. It supports dual-port selection (LNBA/LNBB), built-in factory-trimmed 22 kHz oscillator (±2 kHz tolerance), dynamic short-circuit protection with 4.7 µF CEXT timing, and dual supply inputs (VCC1 ≥15 V, VCC2 ≥22 V) for optimized dissipation.

For engineers reviewing the LNBK20PD-TR datasheet, LNBK20PD-TR pinout, LNBK20PD-TR application, or LNBK20PD-TR equivalent, key selection criteria include output voltage selection logic (VSEL/LLC), stand-by backward current limit (≤3 mA), tone enable response time, thermal shutdown threshold (150 °C), and compatibility with DiSEqC™ burst coding requirements in analog/digital satellite receivers.

Technical Context

The LNBK20PD-TR integrates two independent LNB output regulators with logic-controlled port selection (OSEL), voltage selection (VSEL), and line-length compensation (LLC) to adjust output by +1 V. Its internal dual-supply switch automatically routes VCC1 (15–27 V) for 13/14 V outputs or VCC2 (22–27 V) for 18/19 V outputs, minimizing power loss.

It implements fast-start 22 kHz tone generation (ENT pin), auxiliary AC-coupled modulation (EXTM), and dynamic overload protection using external CEXT capacitor-triggering 1100 ms OFF time and ~73 ms ON time (t_ON = t_OFF/15) with open-collector OLF flag reporting fault status.

Key Specifications

Pinout & Package

Package: PowerSO-20, surface-mount, thermally enhanced with exposed die pad (R_thJC = 2 °C/W). Designed for high-power LNB interface applications requiring efficient heat transfer to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LNBK20PD-TR, LNBP20CR offers higher drive strength for demanding LNB loads but shares identical control architecture, while LNBK10SP trades functionality and thermal performance for footprint reduction - making LNBK20PD-TR the balanced choice for dual-port, diagnostic-aware designs.

Availability

LNBK20PD-TR is available at Aetrix Electronics and suitable for satellite receiver manufacturing, DiSEqC™-enabled tuner modules, and dual-LNB front-end development requiring stable component supply across industrial temperature range and long-lifecycle programs.

Supply support for LNBK20PD-TR 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 strong analog and power management heritage.

LNBK20PD-TR belongs to ST's dedicated LNB interface product line, engineered specifically for satellite receiver power and control subsystems - balancing thermal efficiency, protocol compliance, and system-level diagnostics.

FAQ

What is the maximum allowable coaxial cable length when using LNBK20PD-TR with LLC compensation?

With LLC = HIGH, the +1 V output boost compensates for typical RG-6 cable voltage drop (~0.33 V/m at 500 mA). At rated 500 mA load, this supports up to ~30 m of standard coax before reaching LNB minimum operating voltage (11 V). Actual reach depends on cable quality, ambient temperature, and LNB quiescent current.

Can LNBK20PD-TR be used with a single 23 V supply connected to both VCC1 and VCC2?

Yes - the datasheet explicitly permits powering both VCC1 and VCC2 from a common 23 V source. The internal supply selector remains functional, and all electrical characteristics (output regulation, thermal behavior, protection timing) are preserved. This simplifies power design but increases dissipation at 13 V output.

How does the dynamic overload protection behave during repeated short-circuit events?

Each short-circuit triggers a fixed 1100 ms OFF period (set by CEXT), followed by a 73 ms ON test window. If overload persists, the cycle repeats indefinitely until fault removal. Total power dissipation during cycling is <1.5 W average - significantly lower than continuous shutdown, preserving reliability.

Is external filtering required on the EXTM pin when not in use?

No - the datasheet states EXTM "can be left open" if unused. However, for noise immunity in high-EMI environments, a 100 kΩ pull-down resistor to GND is recommended. No capacitor or series termination is needed unless active modulation is implemented.