onsemi KA78L05AMTF

Overview

KA78L05AMTF from Fairchild Semiconductor is a fixed-output +5V, 100mA positive linear voltage regulator in SOT-89 package, featuring thermal overload protection, short-circuit current limiting, ±5% output voltage tolerance, and 1.7V dropout voltage at 25°C. It delivers stable low-power bias for microcontroller peripherals, sensor interfaces, and logic-level circuitry in space-constrained industrial control modules.

For engineers reviewing the KA78L05AMTF datasheet, pinout, applications, or equivalent options, key selection criteria include its SOT-89 thermal performance (PD ≤ 0.75W), 7–20V input range, 4.85–5.15V output under load, 80dB ripple rejection at 120Hz, and compatibility with 0.33µF input / 0.1µF output ceramic capacitors.

Technical Context

The KA78L05AMTF implements a monolithic three-terminal linear regulation architecture with internal reference voltage, error amplifier, series pass transistor, short-circuit protection, and thermal shutdown circuitry. Its design centers on fixed +5V output stabilization without external components beyond recommended bypass capacitors.

It operates across 0°C to +125°C junction temperature, supports 1mA–100mA load current, and maintains regulation with input voltages from 7V up to 30V - requiring ≥2.7V headroom (VD = 1.7V typical) for full-load operation. Ripple rejection and line/load regulation are specified under defined test conditions (CI = 0.33µF, CO = 0.1µF).

Key Specifications

Pinout & Package

SOT-89 package: 3-pin surface-mount plastic package with exposed thermal pad (pin 2 is GND and thermally connected to tab); compact 4.50 × 2.50 mm footprint optimized for high thermal efficiency in low-power applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar +5V, 100mA linear regulator applications.

Compared with LM78L05ACZ and MC78L05ABD, the KA78L05AMTF offers best-in-class 80dB ripple rejection and SOT-89 thermal efficiency for 5V/100mA regulation in compact industrial PCBs - making it optimal where noise immunity and board area are critical.

Availability

KA78L05AMTF is available at Aetrix Electronics and suitable for industrial sensor interfaces, microcontroller power rails, IoT edge node bias, and legacy RS-232 transceiver supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for KA78L05AMTF 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

Fairchild Semiconductor was a U.S.-based analog and power IC manufacturer acquired by ON Semiconductor in 2016; known for robust, cost-effective linear regulators and discrete power devices.

The KA78LXXA series was designed specifically for low-power, space-constrained industrial and consumer applications requiring reliable fixed-voltage regulation without external compensation components.

FAQ

What is the maximum input voltage rating for KA78L05AMTF?

The KA78L05AMTF has an absolute maximum input voltage of 30V for 5V output versions. Operation above this voltage risks permanent damage. For reliable long-term use, keep input within 7–25V to maintain thermal margin and ensure 1.7V dropout headroom - the KA78L05AMTF datasheet specifies 7–20V for optimal line regulation performance.

Does KA78L05AMTF require external capacitors, and what values are recommended?

Yes, the KA78L05AMTF requires two external ceramic capacitors: a 0.33µF input capacitor placed within 5mm of pin 3 (Input), and a 0.1µF output capacitor placed adjacent to pin 1 (Output). These values are validated in the KA78L05AMTF datasheet for stability, transient response, and ripple suppression - using larger or electrolytic types may degrade performance or cause oscillation.

Can KA78L05AMTF deliver its full 100mA output current continuously?

The KA78L05AMTF is rated for 100mA maximum output current, but continuous delivery depends on thermal conditions. With its SOT-89 package and 0.75W power dissipation limit, full 100mA is sustainable only if input voltage stays near minimum (e.g., 7V) and ambient temperature remains ≤50°C. At 12V input and 25°C ambient, derating to ~65mA is typical to avoid thermal shutdown - the KA78L05AMTF thermal protection activates at ~150°C junction temperature.

How does KA78L05AMTF compare to standard 78L05 regulators in terms of noise and ripple rejection?

The KA78L05AMTF provides 40µV/V_O output noise (10Hz–100kHz) and 80dB ripple rejection at 120Hz - significantly better than legacy 78L05 variants like LM78L05ACZ (typically 45dB PSRR). This makes the KA78L05AMTF especially suitable for noise-sensitive analog circuits. The improved performance is inherent to its internal bandgap and error amplifier design, confirmed in KA78L05AMTF electrical characteristics tables.

Is KA78L05AMTF pin-compatible with other SOT-89 5V regulators such as MC78L05ABP?

No, KA78L05AMTF is not pin-compatible with MC78L05ABP. While both use SOT-89 packages, KA78L05AMTF pinout is Input–GND–Output (pin 3–2–1), whereas MC78L05ABP uses Output–GND–Input (pin 1–2–3). Swapping them without PCB revision will cause reverse polarity and immediate failure. Always verify pin mapping using the official KA78L05AMTF datasheet before substitution.