STMicroelectronics STLD1TR

Overview

STLD1TR from STMicroelectronics is a dual-channel, high-current line driver IC designed for narrow-band power-line communication (PLC) systems. It delivers up to 1.5 ARMS output current, supports 8–18 V single-supply operation, provides 18 V_p-p single-ended / 36 V_p-p differential output swing, and features embedded thermal shutdown and current sense feedback - enabling robust signal injection into 5–100 Ω AC mains loads in smart metering and grid-edge IoT nodes.

For engineers reviewing the STLD1TR datasheet, STLD1TR pinout, STLD1TR application, or STLD1TR equivalent, key selection considerations include its dual-amplifier topology with independent enable control (TX_ON_1/TX_ON_2), low 0.1 Ω typical output impedance, -72 dBc in-band IM3 at 50/80 kHz, SFDR ≥69 dBc, and QFN24 (4×4 mm) package with exposed thermal pad.

Technical Context

The STLD1TR integrates two fully independent, rail-to-rail capable Class-AB power amplifiers with externally configurable gain and bias via PAx_INP/INN inputs. Each amplifier features active Hi-Z disable (via TX_ON_x), current-sense output (CSF_OUT) with 106 A/A ratio, and thermal monitoring via proportional THERM current output scaled to IBIAS_IN.

Its internal 5 V linear regulator (AVDD_5V) powers analog circuitry from the same 8–18 V PVCC/VCC supply, eliminating need for external LDOs. The device achieves <0.1 Ω output impedance in RX mode and maintains <−70 dB THD across 50–500 kHz while meeting CENELEC A/B, FCC Part 15, and ARIB STD-T108 emission limits through ultra-low harmonic distortion and spurious-free dynamic range.

Key Specifications

Pinout & Package

STLD1TR is housed in a thermally enhanced QFN24L (4 × 4 × 1 mm) package with an exposed thermal pad that must be connected to AGND on the PCB for optimal thermal performance and EMI suppression.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel PLC line driver applications.

Compared with TI TSS721A and ADF7023+ADL5562, STLD1TR uniquely combines dual-channel independence, integrated thermal/current feedback, and regulatory-ready distortion performance in a single QFN24 package - reducing design risk and validation time for certified narrowband PLC endpoints.

Availability

STLD1TR is available at Aetrix Electronics and suitable for smart metering, grid-edge IoT nodes, and PRIME/G3-PLC gateways requiring stable component supply across extended industrial temperature ranges (−40 °C to +105 °C) and long product lifecycles.

Supply support for STLD1TR 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 power management ICs with strong emphasis on embedded systems and connectivity solutions.

The STLD1TR belongs to ST's Power Line Communication (PLC) Interface portfolio, engineered specifically to simplify certified narrowband PLC transmitter design by integrating high-current drivers, thermal intelligence, and regulatory-compliant linearity in one device.

FAQ

What is the recommended PCB layout practice for the exposed thermal pad on STLD1TR?

The exposed pad (Pin 25) must be soldered to a solid AGND copper plane with ≥4 thermal vias (0.3 mm diameter) connecting to inner-layer ground planes. Avoid splitting the pad or routing signals underneath it. This ensures ≤35 °C/W junction-to-ambient thermal resistance and prevents thermal shutdown during sustained 1.5 ARMS operation.

Can STLD1TR operate in single-ended mode while disabling one amplifier?

Yes. Drive only PA1_OUT with PA2_OUT disabled by holding TX_ON_2 low (≤0.95 V). PA2_OUT enters ~30 kΩ Hi-Z state, isolating it from the load. The remaining amplifier maintains full 1.5 ARMS capability and all specifications - confirmed in DS12339 Rev 2, Table 5 (Tx mode, single PA configuration).

How is the CSF_OUT current used for overcurrent protection?

CSF_OUT delivers a current equal to 106× the PA output current. Connect a precision resistor (e.g., 10 Ω) from CSF_OUT to AGND to generate a voltage proportional to load current. Feed this voltage to a comparator referenced to 159 mV to detect >1.5 ARMS - matching the absolute maximum rating in Table 2.

Does STLD1TR support automatic thermal foldback without external circuitry?

No. While THERM provides four-level current-scaled feedback (0× to 4× IBIAS_IN), external logic (e.g., microcontroller ADC or comparator) is required to interpret levels and reduce TX_ON duty cycle or lower signal amplitude. The IC self-disables only at Tj > 170 °C (T4 threshold), per Section 5.1.