UMW 78L05 Overview
The UMW 78L05 is a fixed-output 5V positive linear voltage regulator belonging to UMW’s 78L series of monolithic integrated circuit regulators — one of the most enduringly popular linear regulator families in electronics, trusted across decades of design for its simplicity, reliability, and near-universal PCB footprint compatibility. The UMW 78L05 provides a stable, internally regulated 5V output at load currents up to 100mA, accepting input voltages up to 30V — giving it a wide input headroom that suits a broad range of unregulated DC supply rails, battery voltages, and adapter outputs. It is designed for applications where a clean, fixed 5V supply is required for digital logic, microcontrollers, sensors, or reference circuitry, without the complexity or cost of a switching regulator.
The UMW 78L05 operates with a quiescent current of just 2mA, keeping self-heating and no-load power draw low in continuously powered applications. Internal circuitry provides thermal overload protection and current limiting, automatically reducing output current or shutting down the device before junction temperature reaches a damaging level — protecting both the regulator and downstream circuitry under short-circuit or overload fault conditions. The device requires only small ceramic or electrolytic capacitors on the input and output pins to achieve stable regulation and good transient response; a minimum of 0.1µF on the input and 0.1µF on the output is recommended, with larger electrolytic capacitors improving load transient performance in noise-sensitive circuits.
Housed in the SOT-89-3 surface-mount package, the UMW 78L05 is a compact, thermally capable SMD component well-suited to space-constrained PCBs in consumer electronics, industrial sensor nodes, and embedded system power rails. The SOT-89-3 pinout (Input – GND – Output) is the industry-standard configuration shared across all major 78L05 manufacturers, enabling a direct drop-in board-level substitution from brands including TI, STMicroelectronics, onsemi, and Diodes Inc. ABL Semi stocks the UMW 78L05 as a fully authentic, original UMW factory product, with flexible MOQ from prototype through to volume production and full compliance documentation for UK and European customers.
Key Specifications
| Parameter | Value |
|---|---|
| Device Type | Fixed Positive Linear Voltage Regulator |
| Fixed Output Voltage (VOutput) | 5V |
| Maximum Output Current (IOutput) | 100mA |
| Maximum Input Voltage | 30V |
| Quiescent Current (Iq) | 2mA |
| Dropout Voltage | Typically 1.7V at 100mA (see datasheet) |
| Internal Protections | Thermal shutdown, output current limiting |
| Minimum Input Capacitor | 0.1µF recommended |
| Minimum Output Capacitor | 0.1µF recommended |
| Output Voltage Tolerance | ±5% typical |
| Package | SOT-89-3 |
Applications
The UMW 78L05 is suited to any application requiring a stable, regulated 5V supply at currents up to 100mA from a higher unregulated or semi-regulated DC input. Primary application areas include microcontroller auxiliary power rails, TTL and CMOS logic supply regulation, sensor and transducer excitation supplies, op-amp bias rails, and RS-232 interface power supplies. The device is equally applicable in industrial control modules, home automation sensor nodes, legacy system power retrofits, and low-power IoT edge devices, where its simplicity, wide input voltage range, and compact SOT-89-3 footprint provide a cost-effective regulated 5V supply with minimal external component requirements.
Pin-to-Pin Compatible Alternatives
The UMW 78L05’s SOT-89-3 pinout is the universal industry standard for the 78L05 fixed 5V regulator, shared identically across all major manufacturers — enabling direct board-level substitution from any branded source to the UMW device with zero PCB modification and immediate cost savings.
| Reference Part Number | Original Manufacturer | Why Choose UMW 78L05 |
|---|---|---|
| UA78L05ACPK | Texas Instruments | The reference 78L05 device in SOT-89; UMW 78L05 is a pin-identical replacement with equivalent 5V/100mA/30V specification at a lower unit cost with flexible MOQ from ABL Semi UK stock |
| MC78L05ACPG | onsemi | onsemi’s widely deployed 78L05 in SOT-89-3; UMW 78L05 provides direct footprint and electrical replacement with equivalent thermal protection and output tolerance at competitive pricing |
| L78L05ACUTR | STMicroelectronics | ST’s popular SOT-89 fixed 5V regulator; UMW 78L05 is a pin-compatible drop-in alternative with identical operating parameters and the same thermal shutdown and current limiting protections |
| AP78L05SAG-7 | Diodes Inc. | Fixed 5V 100mA regulator in SOT-89; UMW 78L05 provides equivalent regulation performance with a wider distributor stock availability from ABL Semi for both prototype and volume orders |
| NJM78L05UA | Nisshinbo Micro Devices (JRC) | Japanese-branded 78L05 in SOT-89; UMW 78L05 offers an identical-footprint cost-reduction alternative with equivalent 30V input voltage rating and 100mA output capability |
Frequently Asked Questions
Is UMW 78L05 RoHS compliant?
Yes. The UMW 78L05 is fully RoHS compliant. UMW manufactures the 78L05 in accordance with EU RoHS Directive 2011/65/EU, ensuring the device is free from restricted hazardous substances including lead and mercury. ABL Semi can provide full compliance and trade documentation upon request to support UK and European regulatory and procurement requirements.
What are the pin-to-pin replacements for UMW 78L05?
The UMW 78L05 is a direct pin-to-pin replacement for the TI UA78L05, onsemi MC78L05, STMicroelectronics L78L05, Diodes Inc. AP78L05, and Nisshinbo NJM78L05 — all of which share the identical SOT-89-3 pinout and 5V/100mA electrical specification. Refer to the compatibility table above for a detailed comparison.
What is the minimum order quantity (MOQ) for UMW 78L05?
ABL Semi offers flexible MOQ for UMW 78L05, supporting both prototype quantities and mass production orders. Contact us for current stock and pricing.
What package options are available for UMW 78L05?
The UMW 78L05 is available in the SOT-89-3 (3-pin small outline transistor) surface-mount package. The SOT-89-3 provides a modest exposed tab that aids heat dissipation into the PCB copper, improving continuous current capability compared to the smaller SOT-23 package. The Input–GND–Output pinout is identical across all major 78L05 manufacturers in this package, confirming the UMW 78L05 as a true board-level drop-in replacement. Contact ABL Semi to confirm current stock availability.
What is the minimum input voltage required to maintain 5V regulation with the UMW 78L05?
The UMW 78L05 requires the input voltage to exceed the output voltage by at least the device’s dropout voltage — typically around 1.7V at 100mA output. This means a minimum input voltage of approximately 6.7V is needed to maintain a regulated 5V output at full load. In practice, an input of 7V or above is recommended to provide margin against input voltage ripple, dropout variation across temperature, and component-to-component tolerance. If the input voltage is likely to fall below 7V in operation — for example in battery-powered applications as the battery discharges — the output regulation will degrade and ultimately drop out of regulation, so designers should confirm the minimum operating input voltage against the expected supply rail range throughout the battery discharge cycle.
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