Texas Instruments LM78L05ACZ

Overview

LM78L05ACZ from Texas Instruments is a 3-pin TO-92 packaged, 5 V fixed-output linear voltage regulator delivering up to 100 mA output current with ±5% output voltage tolerance over temperature, input voltage range up to 30 V, and integrated thermal overload and short-circuit protection - widely used in battery-powered instrumentation and low-wattage power supplies.

For engineers reviewing the LM78L05ACZ datasheet, LM78L05ACZ pinout, LM78L05ACZ application, or LM78L05ACZ equivalent, key selection criteria include dropout voltage (1.7 V at 100 mA), quiescent current (3–5 mA), ripple rejection (47–62 dB at 120 Hz), and thermal performance in the TO-92 package (R_θJA = 158.7 °C/W).

Technical Context

The LM78L05ACZ implements a classic three-terminal series pass architecture with internal bandgap reference, error amplifier, and Darlington output transistor. It operates without external components but requires ≥0.01 µF output capacitance for high-frequency noise suppression and benefits from a 0.33 µF input capacitor when placed >3 inches from the source filter.

Its protection features include foldback current limiting (peak output current = 140 mA), safe-area protection limiting internal power dissipation, and thermal shutdown activation at junction temperatures exceeding 125 °C - enabling robust operation in unregulated input environments such as wall adapters and automotive accessory rails.

Key Specifications

Pinout & Package

LM78L05ACZ is supplied in the 3-pin TO-92 plastic package (body size 3.70 mm × 4.70 mm), with leads arranged in bottom-view orientation: Pin 1 = V_OUT, Pin 2 = GND, Pin 3 = V_IN. This through-hole package supports manual assembly and prototyping while offering moderate thermal performance (R_θJA = 158.7 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L05ACM and MC78L05ACP, the LM78L05ACZ offers lowest-cost through-hole assembly, proven legacy reliability in TO-92, and direct compatibility with breadboard and hand-soldered prototypes - making it optimal for evaluation, low-volume production, and service replacement.

Availability

LM78L05ACZ is available at Aetrix Electronics and suitable for battery chargers, portable instrumentation, and LED lighting applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LM78L05ACZ 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

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, specializing in analog, embedded processing, and digital signal technologies for industrial, automotive, and consumer markets.

The LM78Lxx series was designed as a low-cost, easy-to-use fixed-output linear regulator family targeting space- and cost-constrained applications where simplicity, reliability, and broad temperature operation are prioritized over ultra-low dropout or ultra-low IQ.

FAQ

What is the maximum input voltage for LM78L05ACZ?

The absolute maximum input voltage for LM78L05ACZ is 35 V, but the recommended operating maximum is 30 V. Exceeding 30 V risks exceeding safe power dissipation limits in the TO-92 package, especially at elevated ambient temperatures. The minimum input voltage to maintain regulation is 6.7 V at 25 °C, increasing with load and temperature.

Does LM78L05ACZ require external capacitors?

LM78L05ACZ does not require external capacitors to function, but TI strongly recommends a 0.33 µF ceramic or tantalum capacitor on the input if the device is placed more than 3 inches from the main filter capacitor, and a minimum 0.01 µF ceramic capacitor on the output to suppress high-frequency noise and ensure stability - both are critical for reliable operation per the datasheet.

What is the thermal resistance of LM78L05ACZ in TO-92 package?

The junction-to-ambient thermal resistance (R_θJA) of LM78L05ACZ in the TO-92 (LP) package is 158.7 °C/W under standard JEDEC test conditions. This value assumes no added heatsink; actual thermal performance improves significantly with PCB copper pour or mechanical heatsinking - essential for sustaining 100 mA output near ambient temperature limits.

Can LM78L05ACZ be used in adjustable-output configurations?

Yes, LM78L05ACZ can be configured as an adjustable regulator by connecting its GND pin to the center of a resistive divider between V_OUT and ground - effectively using the internal 5 V reference to set higher output voltages. However, this configuration alters load regulation and requires careful resistor selection to maintain accuracy and stability per Figure 10 in the datasheet.

Is LM78L05ACZ pin-compatible with other LM78Lxx variants?

Yes, all LM78Lxx devices including LM78L05ACZ, LM78L12ACZ, and LM78L15ACZ share identical TO-92 pinout (Pin 1 = V_OUT, Pin 2 = GND, Pin 3 = V_IN), enabling drop-in replacement across output voltages in existing designs - provided input voltage headroom and load current requirements remain within each variant's specification limits.