STMicroelectronics L78L05CD13TR

Overview

L78L05CD13TR from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 5 V output at up to 100 mA, featuring internal current limiting, thermal overload protection, and short-circuit protection. It requires no external components, operates with input voltages up to 30 V (for 5 V output), and maintains ±4% output tolerance over temperature and load. It is used for local on-card regulation in microcontroller power domains, sensor interface rails, and low-power industrial control modules.

For engineers reviewing the L78L05CD13TR datasheet, L78L05CD13TR pinout, L78L05CD13TR application, or L78L05CD13TR equivalent, this device serves as a drop-in replacement for legacy 78L05 regulators in space-constrained designs requiring stable 5 V bias with low quiescent current (6 mA typ.), low noise (40 µV RMS), and high supply rejection (41–49 dB at 120 Hz).

Technical Context

The L78L05CD13TR implements a monolithic bipolar linear regulator architecture with built-in foldback current limiting and thermal shutdown circuitry, ensuring robust operation under fault conditions without external supervision. Its internal bandgap reference and error amplifier maintain output regulation across ambient temperatures from 0 °C to 125 °C (L78L05C grade) and load currents from 1 mA to 100 mA.

It achieves 40 µV RMS output noise (10 Hz–100 kHz) and 41–49 dB supply voltage rejection at 120 Hz due to integrated ripple filtering and stable loop compensation. Dropout voltage is specified at 2 V, requiring minimum input of 7 V for full-load 5 V output compliance.

Key Specifications

Pinout & Package

Supplied in SO-8 package (ECOPACK® compliant), with pins 2, 3, 6, and 7 internally connected to the die attach flag for enhanced thermal performance. Requires ≥6 cm² copper pour for optimal power dissipation (R_thJA = 55 °C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output linear regulator applications.

Compared with MC78L05ACDR2G and TL750L05IDRG4, the L78L05CD13TR uniquely balances ±4% tolerance, SO-8 thermal performance, and 40 µV noise in a single industrial-grade package - making it optimal for space-constrained, thermally demanding 5 V regulation where both accuracy and reliability are critical.

Availability

L78L05CD13TR is available at Aetrix Electronics and suitable for industrial sensor nodes, microcontroller power domains, IoT edge peripherals, and legacy equipment retrofits requiring stable component supply with guaranteed long-term sourcing.

Supply support for L78L05CD13TR 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The L78L series belongs to ST's legacy linear regulator product line, engineered specifically for cost-effective, robust local regulation in space- and thermal-constrained embedded systems - emphasizing fault resilience, ease of use, and broad operating range.

FAQ

What is the maximum allowable input voltage for L78L05CD13TR?

The absolute maximum DC input voltage is 30 V when regulating 5 V output, per Table 1 of DS0424 Rev 30. Operation above this risks permanent damage. For reliable long-term use, ST recommends limiting input to ≤25 V to maintain safe junction temperature margins under full 100 mA load.

Does L78L05CD13TR require input and output capacitors?

Yes - ST specifies a minimum 0.33 µF ceramic capacitor at the input pin and 0.1 µF ceramic capacitor at the output pin, placed as close as possible to the device. These stabilize internal feedback, suppress high-frequency noise, and prevent oscillation; omitting them may cause regulation instability or increased output ripple.

Can L78L05CD13TR be used in automotive applications?

No - the L78L05CD13TR is rated for 0 °C to 125 °C operating junction temperature (L78L05C grade), not the extended -40 °C to 150 °C required for AEC-Q100 automotive qualification. For automotive use, ST recommends the L78L05AB variant (–40 °C to 125 °C) or automotive-qualified alternatives like TLE4275.

How does thermal performance differ between SO-8 and TO-92 packages of L78L05?

In SO-8, pins 2/3/6/7 are internally connected to the die attach flag, reducing R_thJA to 55 °C/W with 6 cm² PCB copper (vs. 200 °C/W for TO-92). This allows ~3× higher continuous power dissipation - enabling 100 mA at 25 °C ambient in SO-8, whereas TO-92 saturates thermally above ~35 mA without heatsinking.