STMicroelectronics LNBH29QTR

Overview

LNBH29QTR from STMicroelectronics is a monolithic LNB supply and control IC with integrated step-up DC-DC converter and I²C interface, designed for satellite receiver front-end power and signaling. It delivers regulated 13/18 V output (programmable via I²C), generates compliant 22 kHz tone (±0.5% accuracy), supports up to 550 mA output current (set by external resistor), achieves 93% typical efficiency at 0.5 A, and integrates overload/overtemperature protection with I²C diagnostic bits - deployed in STB, TV, and PC-card satellite receivers.

For engineers reviewing the LNBH29QTR datasheet, LNBH29QTR pinout, LNBH29QTR application, or LNBH29QTR equivalent, this device serves as a complete single-chip solution for LNB power delivery and DiSEqC™ signaling - requiring no external voltage references, minimal passive count, and direct I²C configuration of output voltage, current limit, and boost compensation mode.

Technical Context

The LNBH29QTR implements a two-stage regulation architecture: a high-efficiency PWM step-up converter (driving an integrated N-MOS) generates VUP (typically 19–22 V), which feeds a low-drop linear post-regulator delivering precise 13/18 V on VOUT. The internal 22 kHz tone generator is factory-trimmed to ±0.5% and maintains waveform integrity even at no load.

I²C control enables real-time configuration of output voltage (3-bit programmable), current limit (via ISEL resistor selection), boost capacitor type (ceramic vs. electrolytic via COMP bit), and diagnostics readback (VMON, PDO, PNG, OLF, OTF bits). Undervoltage lockout activates below 4.7 V, and dynamic short-circuit protection cycles 90 ms ON / 900 ms OFF to limit thermal stress.

Key Specifications

Pinout & Package

Package: QFN16 (4×4 mm, 0.5 mm pitch), exposed thermal pad (Epad) connected to GND for enhanced thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX2181AETL+, LNBH29QTR reduces system-level component count by integrating tone generation and eliminates timing skew between voltage and tone edges; compared with LMX2531LQ1770E/NOPB, it provides complete power + signaling functionality where RF synthesis is irrelevant.

Availability

LNBH29QTR 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 consistent electrical performance across production batches.

Supply support for LNBH29QTR 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, designing and manufacturing analog, mixed-signal, power, and microcontroller solutions for industrial, automotive, and consumer markets.

The LNBH29 series belongs to ST's broadcast and satellite interface product line, engineered specifically to consolidate LNB power delivery, DiSEqC™ signaling, and diagnostics into a single monolithic IC for cost-sensitive, space-constrained satellite receiver designs.

FAQ

What is the maximum output current capability of the LNBH29QTR, and how is it configured?

The LNBH29QTR supports up to 550 mA output current, set by an external resistor (RSEL) connected between the ISEL pin and GND. The relationship follows IMAX(typ.) = 13915 / RSEL(kΩ) mA. For example, a 24.3 kΩ resistor yields 573 mA, but the datasheet specifies 550 mA as the maximum validated limit. This resistor-based configuration allows precise tailoring to specific LNB load requirements without firmware changes.

Does the LNBH29QTR support both 13 V and 18 V LNB outputs, and how is voltage selection performed?

Yes, the LNBH29QTR supports both 13 V and 18 V outputs via three programmable bits (V1, V0, VSEL) in the I²C DATA register. Valid combinations are 000 (13 V), 001 (18 V), and others reserved for future use. Voltage selection occurs digitally through the I²C interface - no external resistors or jumpers are needed, enabling dynamic polarity switching during DiSEqC™ multi-switch operation.

How does the LNBH29QTR handle overtemperature and overcurrent faults, and what diagnostic feedback is provided?

The LNBH29QTR features autonomous overtemperature (OTF) and overload/short-circuit (OLF) protection. When junction temperature exceeds 150 °C or output current exceeds the ISEL-set limit, the device shuts down the step-up converter and linear regulator. Both conditions set corresponding bits in the I²C STATUS register, readable by the host MCU. After fault removal, operation resumes automatically, and diagnostic bits clear upon next STATUS register read.

Is the LNBH29QTR pin-compatible with other variants in the LNBH29 family, such as the LNBH29PTR?

No - the LNBH29QTR uses QFN16 (4×4 mm), while the LNBH29PTR uses QFN16 (3×3 mm). Although both share identical pin functions and numbering (per Figure 4), their land patterns, thermal pad dimensions, and mechanical footprints differ. PCB layout must be redesigned when substituting between QTR and PTR variants; they are not drop-in replacements despite functional equivalence.