STMicroelectronics LM217LD13TR

Overview

LM217LD13TR from STMicroelectronics is a monolithic adjustable positive voltage regulator in SO-8 package, delivering up to 100 mA output current with 1.2–37 V adjustable output range, ±0.7% output voltage temperature stability, and integrated thermal overload and short-circuit protection. It operates in floating configuration for high-voltage applications such as industrial power supplies and programmable lab bench supplies.

For engineers reviewing the LM217LD13TR datasheet, LM217LD13TR pinout, LM217LD13TR application, or LM217LD13TR equivalent, key selection criteria include output adjustability via resistive divider, low adjustment pin current (≤100 µA), line regulation (0.01% typ.), load regulation (0.1% typ.), and SO-8 thermal performance (R_thJA = 55 °C/W with 6 cm² copper heatsink).

Technical Context

The LM217LD13TR implements a bandgap-referenced feedback loop with internal 1.25 V reference voltage between OUT and ADJ pins, enabling precise output setting using two external resistors. Its quiescent current flows entirely into the output terminal, requiring ≥3.5 mA minimum load current to maintain regulation.

It features safe-area compensation for output transistors, allowing stable operation under transient overloads. The SO-8 package uses internally connected pins 2, 3, 6, and 7 to the die attach flag-reducing thermal resistance and improving power dissipation capability when PCB copper area is used as heatsink.

Key Specifications

Pinout & Package

LM217LD13TR is housed in an SO-8 surface-mount package with exposed die attach flag connected internally to pins 2 (IN), 3 (OUT), 6, and 7 for enhanced thermal conduction. Pin 1 is ADJUST, pin 2 is INPUT, pin 3 is OUTPUT, and remaining pins are NC or internally tied.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable linear regulator applications.

Compared with LM317LD13TR, the LM217LD13TR offers extended temperature support for industrial environments; versus TLV1117-ADJ, it trades higher dropout for full 37 V output range and true floating operation-making it uniquely suited for high-differential, isolated, or wide-range biasing tasks.

Availability

LM217LD13TR is available at Aetrix Electronics and suitable for industrial sensor bias supplies, programmable lab power modules, and embedded system auxiliary rails requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for LM217LD13TR 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, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The LM217L series belongs to ST's precision linear regulator product line, engineered specifically for applications demanding wide output adjustability, thermal resilience, and floating operation in harsh or space-constrained environments.

FAQ

What is the minimum load current required for stable regulation with LM217LD13TR?

The LM217LD13TR requires a minimum load current of 3.5 mA when the input-output differential voltage is 40 V, and 5 mA under typical conditions. This is necessary because all quiescent current returns to the output terminal; insufficient load causes output voltage to rise uncontrollably. A bleeder resistor is commonly used to meet this requirement in light-load or no-load scenarios.

Can LM217LD13TR be used in floating (high-side) configurations?

Yes-LM217LD13TR is explicitly designed for floating operation. It regulates based solely on the voltage difference between IN and OUT pins, not ground. This allows use as a high-side regulator-for example, generating +15 V referenced to a 400 V DC bus-provided the VI–VO differential remains ≤40 V and thermal limits are observed via PCB copper heatsinking.

How does the SO-8 package thermal performance compare to TO-92 versions?

The SO-8 package achieves R_thJA = 55 °C/W with 6 cm² copper heatsink, significantly better than TO-92's 200 °C/W. Internally connected pins 2, 3, 6, and 7 tie directly to the die attach flag, enabling efficient heat transfer into the PCB. This allows ~625 mW continuous dissipation at T_J = 125°C-more than double what TO-92 can sustain-making SO-8 ideal for higher-power or thermally dense designs.

What is the role of the adjustment pin current (I_ADJ) in output voltage accuracy?

I_ADJ (50–100 µA) flows out of the ADJ pin and into the R2 resistor in the standard feedback divider. It introduces an error term I_ADJ × R2 in the output voltage equation VO = V_REF(1 + R2/R1) + I_ADJR2. Because I_ADJ is low and stable, this error is typically negligible when R2 ≤ 10 kΩ-preserving ±1% output accuracy without trimming.