Renesas UPC79L12J-A

Overview

UPC79L12J-A from NEC Electronics is a three-terminal negative voltage regulator delivering fixed −12 V output with 100 mA maximum output current, internal overcurrent and thermal shutdown protection, and TO-92 package. It stabilizes unregulated DC inputs (−14.5 V to −27 V) for low-power analog and digital subsystems requiring clean negative rail supply.

For engineers reviewing the UPC79L12J-A datasheet, UPC79L12J-A pinout, UPC79L12J-A application, or UPC79L12J-A equivalent, key selection criteria include dropout voltage (0.9 V), ripple rejection (55–70 dB), output noise (88–280 μV r.m.s.), and thermal resistance (180 °C/W) in constrained ambient environments.

Technical Context

The UPC79L12J-A operates as a monolithic bipolar linear regulator using internal error amplification and series pass transistor control to maintain stable −12 V output across load (1–100 mA) and line (−14.5 V to −27 V) variations. Its architecture integrates on-chip current limiting and thermal foldback to prevent damage during overload or elevated junction temperature.

Designed for through-hole mounting in TO-92, it requires external input (≥2.2 μF) and output (≥1 μF) capacitors placed within 2 cm of pins; reverse-polarity diodes D1 and D2 are recommended when VIN > VO or VO > GND to protect against transient backfeed conditions.

Key Specifications

Pinout & Package

UPC79L12J-A uses a 3-pin plastic SIP (TO-92) package with standard marking-side orientation: Pin 1 = Input (VIN), Pin 2 = Ground (GND), Pin 3 = Output (VO). The package meets JEDEC TO-92 mechanical dimensions (5.0 mm × 4.0 mm × 15.0 mm) and supports wave soldering (≤260 °C, 10 s).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar negative voltage regulator applications.

Compared with LM7912ACZ and MC79L12ACPG, the UPC79L12J-A offers superior ripple rejection (up to 70 dB) and lower thermal resistance in TO-92, making it optimal for compact, noise-sensitive analog designs where input ripple is high and board area is limited.

Availability

UPC79L12J-A is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, legacy RS-232 transceiver power, and medical ECG front-end bias requiring stable component supply across long-lifecycle embedded programs.

Supply support for UPC79L12J-A 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

NEC Electronics Corporation was a Japanese semiconductor manufacturer specializing in analog, mixed-signal, and microcontroller ICs before merging into Renesas Electronics in 2010.

The μPC79Lxx Series was designed specifically for cost-sensitive, low-power negative voltage regulation in industrial controls, test equipment, and legacy communication interfaces where TO-92 form factor and robust thermal protection were essential.

FAQ

What is the absolute maximum input voltage rating for UPC79L12J-A?

The absolute maximum input voltage for UPC79L12J-A is −35 V at TA = 25°C. Exceeding this value-even momentarily-risks permanent device failure due to junction breakdown. For reliable operation, the recommended input range is −14.5 V to −27 V under typical load conditions. Always verify input transient suppression in your design to ensure UPC79L12J-A remains within its absolute maximum ratings.

Does UPC79L12J-A require external capacitors, and what values are recommended?

Yes, UPC79L12J-A requires both input and output capacitors for stability. A minimum 2.2 μF input capacitor (CIN) is needed if the regulator is located more than a few centimeters from the main power filter. A minimum 1 μF output capacitor (COUT) must be placed within 2 cm of the OUTPUT and GND pins. Ceramic or tantalum types are preferred for low ESR; placement proximity directly affects transient response and noise suppression in the UPC79L12J-A circuit.

How does the thermal shutdown feature operate in UPC79L12J-A?

UPC79L12J-A activates thermal shutdown when junction temperature reaches +150 °C, halting output conduction to prevent damage. The device automatically recovers once TJ falls below +125 °C, restoring regulation without manual reset. This behavior is confirmed in the Absolute Maximum Ratings table and Typical Characteristics curves of the UPC79L12J-A datasheet, making it suitable for enclosed or high-ambient-temperature deployments.

Can UPC79L12J-A be used in battery-powered applications with variable input voltage?

Yes, UPC79L12J-A supports input voltages from −14.5 V to −27 V, enabling use with stacked alkaline or lithium primary batteries (e.g., four −3.6 V LiSOCl₂ cells). Its 0.9 V dropout allows regulation down to −13.0 V input, preserving usable battery life. However, quiescent current (4.4–6.0 mA) must be factored into total system drain-UPC79L12J-A is best suited for medium-duty-cycle portable instruments rather than ultra-low-power IoT sensors.

Is UPC79L12J-A RoHS-compliant and lead-free?

Yes, UPC79L12J-A is explicitly marked as Pb-free in the Ordering Information section of its datasheet: "Note Pb-free (This product does not contain Pb in external electrode and other parts)." It complies with EU RoHS Directive 2011/65/EU and is suitable for environmentally regulated industrial and medical end equipment requiring documented lead-free status.