Texas Instruments LM78M05CH/NOPB

Overview

LM78M05CH/NOPB from Texas Instruments is a fixed-output, 3-terminal positive voltage regulator delivering 5 V ±2.5% at up to 500 mA output current with input voltage range of 7.2 V to 35 V. It integrates thermal shutdown, short-circuit current limiting, and safe-area protection for robust local power regulation in embedded control modules.

For engineers reviewing the LM78M05CH/NOPB datasheet, LM78M05CH/NOPB pinout, LM78M05CH/NOPB application, or LM78M05CH/NOPB equivalent, key selection criteria include dropout headroom (≥2.2 V), junction temperature limit (125°C), TO-220 package thermal resistance (22.6°C/W), and load regulation performance (≤100 mV over 5–500 mA).

Technical Context

The LM78M05CH/NOPB employs a monolithic NPN Darlington pass transistor with built-in current-sense and thermal foldback circuitry. Its regulation loop maintains stable 5 V output without external feedback components, relying on internal bandgap reference and error amplifier.

Operation requires ≥2.2 V input-to-output differential (dropout) to sustain regulation; below this, output collapses linearly. Protection modes-thermal shutdown at ~165°C junction, current limit at ~700 mA, and safe-area compensation-activate autonomously and recover without latch-up.

Key Specifications

Pinout & Package

LM78M05CH/NOPB uses the TO-220 (NDE) 3-pin package with 10.16 mm × 14.986 mm body size and tab-connected ground. The metal tab is electrically tied to Pin 2 (Ground), enabling direct heatsink mounting with electrical isolation required if chassis ground differs from circuit ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78M05CH/NOPB, the TO-252 alternative trades thermal margin for SMT compatibility, while the UA78M05CKCS sacrifices industrial temperature range for lower unit cost - neither offers pin-to-pin or functional drop-in replacement without thermal or environmental validation.

Availability

LM78M05CH/NOPB is available at Aetrix Electronics and suitable for industrial motor drives, smart appliance control modules, and point-of-sale terminals requiring stable component supply with full industrial temperature support (–40°C to +125°C) and long-term lifecycle assurance.

Supply support for LM78M05CH/NOPB 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 power management technologies since 1930.

The LM78Mxx series was designed as a rugged, drop-in-ready linear regulator family for cost-sensitive industrial and consumer systems needing reliable local 5 V, 12 V, or 15 V rails without design complexity.

FAQ

What is the minimum input voltage required for LM78M05CH/NOPB to maintain regulation?

The LM78M05CH/NOPB requires a minimum input voltage of 7.2 V to sustain 5 V output regulation under full 500 mA load, corresponding to a 2.2 V dropout headroom. Below this threshold, output voltage drops linearly with input; operation outside recommended conditions risks instability or premature thermal shutdown.

Does LM78M05CH/NOPB require input and output capacitors to operate stably?

No - the LM78M05CH/NOPB is internally compensated and operates stably without input or output capacitors. However, a 0.33 µF input capacitor is recommended to suppress high-frequency noise, and a 0.1 µF output capacitor improves transient response to load steps. These are design enhancements, not stability requirements.

Can LM78M05CH/NOPB be used in automotive applications?

The LM78M05CH/NOPB is specified for –40°C to +125°C operating junction temperature and features thermal shutdown and short-circuit protection, making it suitable for under-hood or cabin-located automotive subsystems. However, it is not AEC-Q100 qualified; for safety-critical or certified automotive use, TI recommends the TL750L05 or TPS7A47 families.

How does the metal tab on LM78M05CH/NOPB function electrically and thermally?

The metal tab on LM78M05CH/NOPB is internally connected to Pin 2 (Ground) and serves as the primary thermal conduction path from die to heatsink. Electrically, it must be isolated from chassis ground if system ground references differ; thermally, it reduces R_θJC to 1.3°C/W, enabling higher power dissipation than lead-frame-only conduction.

What is the quiescent current behavior of LM78M05CH/NOPB across load conditions?

The LM78M05CH/NOPB draws 4–10 mA quiescent current (I_Q) at 500 mA load, with ΔI_Q ≤0.5 mA variation from 5 mA to 500 mA load. This stable I_Q profile ensures predictable power budgeting in battery-backed or energy-harvesting systems where standby consumption directly impacts runtime.