STMicroelectronics LNBH23LQTR

Overview

LNBH23LQTR from STMicroelectronics is a monolithic LNB supply and control IC designed for satellite receiver front-ends. It integrates a high-efficiency step-up DC-DC converter (93% typ. @ 0.5 A), low-drop linear post-regulator, factory-trimmed 22 kHz tone generator, I²C interface, and DiSEqC™ 1.X encoding support - delivering 13/18 V output to LNBs via VoRX pin with selectable current limit up to 0.65 A.

For engineers reviewing the LNBH23LQTR datasheet, LNBH23LQTR pinout, LNBH23LQTR application, or LNBH23LQTR equivalent, this device serves as a complete single-chip solution for powering and signaling satellite LNBs in STB, TV, and PC card receivers - requiring precise voltage selection, dynamic short-circuit protection, thermal diagnostics, and ESD-hardened output pins (±4 kV).

Technical Context

The LNBH23LQTR implements a two-stage power architecture: a PWM-controlled step-up converter (driving LX pin) generates VUP (typically ~19.1 V), which feeds an internal linear post-regulator to deliver regulated 13 V or 18 V at VoRX with 1.1 V typical dropout. Its I²C interface controls EN, VSEL, TTX, PCL, and LLC bits across an 8-bit system register, enabling real-time diagnostics (OTF/OLF flags) and DiSEqC™ modulation via DSQIN or EXTM pin.

DiSEqC™ 1.X compliance is achieved through three configurable modes: internal 22 kHz tone generation (VoTX → EXTM coupling), external 22 kHz injection (EXTM direct AC coupling), or hybrid use of VoTX as tone source - all synchronized with DSQIN TTL pulses or TEN bit activation. The EXTM pin provides analog gain-based modulation (VoRX(AC) = VEXTM(AC) × GEXTM), eliminating need for external R-L filters in standard designs.

Key Specifications

Pinout & Package

Package: QFN32 (5 × 5 mm) with exposed thermal pad (EpAD), optimized for thermal dissipation in space-constrained satellite receiver modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX2181AETX+, LNBH23LQTR offers lower component count and EXTM-based DiSEqC™ flexibility but lower current capacity; versus SP232EEN-LF, it is functionally distinct - the latter is an RS-232 driver with no LNB supply capability.

Availability

LNBH23LQTR is available at Aetrix Electronics and suitable for STB satellite receivers, TV satellite receivers, and PC card satellite receivers requiring stable component supply, long-term lifecycle support, and full traceability for broadcast equipment manufacturing.

Supply support for LNBH23LQTR 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 portfolios.

The LNBH23LQTR belongs to ST's satellite receiver interface product line, engineered specifically for cost-sensitive, space-constrained DVB-S/S2 front-ends requiring integrated LNB power, tone generation, and DiSEqC™ control in a single QFN package.

FAQ

What is the maximum allowable output current for LNBH23LQTR, and how is it configured?

The maximum output current is 0.65 A typical, set by an external resistor (RSEL) connected between ISEL pin and GND. The relationship is defined as IMAX (A) = 10000 / RSEL (Ω); for example, a 15 kΩ resistor yields ~0.67 A. This threshold is enforced by the internal linear regulator and can be dynamically adjusted via I²C PCL bit during overload conditions.

How does the EXTM pin function in DiSEqC™ 1.X implementations?

The EXTM pin accepts an external 22 kHz AC signal (via DC-blocking capacitor) and superimposes it onto the VoRX DC output using internal analog gain. When used, the TTX bit must be held LOW to disable the internal oscillator. This configuration removes the need for external R-L filtering components and simplifies compliance with DiSEqC™ signal shape requirements.

Can LNBH23LQTR operate from a 12 V supply only, and what is its minimum input voltage?

Yes - the device operates from a single 8 V to 15 V supply on both VCC and VCC–L pins. Its under-voltage lockout disables operation below 6.7 V (typ.), ensuring stable startup and preventing erratic behavior during brown-out conditions common in automotive or battery-backed satellite systems.

What diagnostic functions are accessible via the I²C interface, and how are they reported?

Two real-time diagnostic flags - Over-Temperature Flag (OTF) and Over-Load Flag (OLF) - are reported in bits 7 and 6 of the 8-bit system register (SR) during I²C read mode. Both are active-high and self-clearing upon fault resolution. Additional status bits include EN (enable), VSEL (voltage select), and LLC (line-loss compensation), providing full operational visibility to the host microcontroller.