onsemi MC7915BT

Overview

MC7915BT from onsemi is a fixed-output negative voltage regulator delivering −15 V at up to 1.0 A, featuring internal thermal shutdown, short-circuit current limiting, and safe-area compensation for rugged operation in industrial power supplies. It requires no external components for basic regulation and maintains stable output across input voltages from −17.5 V to −30 V with ≤150 mV load regulation (5–1500 mA) and ≤300 mV line regulation.

For engineers reviewing the MC7915BT datasheet, pinout, applications, or equivalent options, key selection considerations include its −15 V fixed output, TO-220 package with heatsink-compatible Pin 2, dropout voltage of 1.3 V at 1.0 A, 4% output voltage tolerance, and suitability for dual-rail op-amp supplies, MECL logic, and industrial analog circuitry requiring robust negative bias.

Technical Context

The MC7915BT implements a monolithic PNP pass transistor architecture with integrated bandgap reference, error amplifier, and protection circuitry. Its safe-area compensation dynamically reduces short-circuit current as V_CE increases, preventing second breakdown during overload.

Thermal shutdown activates at +150°C junction temperature, and internal current limiting holds peak output current below 2.2 A under short-circuit conditions. The device operates over −40°C to +125°C ambient with internally limited power dissipation and 5.0°C/W junction-to-case thermal resistance in TO-220 packaging.

Key Specifications

Pinout & Package

MC7915BT uses the TO-220 (Case 221AB) package with heatsink surface electrically connected to Pin 2. The case outline conforms to JEDEC MS-001, and Pin 2 must be isolated from chassis ground unless referenced to system ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC7915CTG and LM337T, the MC7915BT offers guaranteed −40°C startup capability and fixed −15 V output without external components - making it optimal for ruggedized industrial systems where simplicity and cold-temperature reliability are mandatory.

Availability

MC7915BT is available at Aetrix Electronics and suitable for industrial control systems, telecom infrastructure, and analog test equipment requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for MC7915BT 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

onsemi (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power management, analog, and sensor solutions for automotive, industrial, and cloud infrastructure markets.

The MC7900 series - including MC7915BT - was designed as a rugged, drop-in complement to the MC7800 positive regulators, targeting industrial power supplies, dual-rail analog systems, and legacy logic families requiring fixed negative voltage rails.

FAQ

What is the maximum input voltage rating for MC7915BT?

The MC7915BT supports a maximum input voltage of −40 V DC under all operating conditions. This rating applies across its full −40°C to +125°C junction temperature range and ensures safe operation even with high-input-ripple or transient-prone supplies. Exceeding −40 V risks permanent damage due to internal junction breakdown.

Does MC7915BT require input and output capacitors for stable operation?

Yes - MC7915BT requires a minimum 0.33 µF input capacitor (tantalum or low-ESR ceramic) placed close to Pins 1 and 2, and a 1.0 µF output capacitor (tantalum preferred) across Pins 1 and 3. These capacitors prevent oscillation, improve transient response, and reduce output noise. Omitting them may cause instability or excessive ripple under dynamic loads.

Can MC7915BT be used in parallel to increase output current?

No - MC7915BT is not designed for parallel operation. Its output voltage tolerance (±4%) and lack of current-sharing circuitry mean mismatched units will cause one device to carry disproportionate current, leading to thermal runaway and premature failure. For >1.0 A, use a single higher-current regulator or external pass transistor boost configuration per Figure 9 in the datasheet.

What thermal management is required for MC7915BT at full 1.0 A load?

At 1.0 A with a −23 V input (typical), MC7915BT dissipates ~8 W (|−23 V − (−15 V)| × 1.0 A). With θ_JA = 65°C/W and ambient at +50°C, junction temperature reaches ~102°C - within spec but near limit. A heatsink with θ_SA ≤ 15°C/W is recommended; mounting with thermal compound and mechanical pressure ensures reliable operation at full load.

Is MC7915BT pin-compatible with other MC7900-series regulators?

Yes - all MC7900-series devices in TO-220 (e.g., MC7905BT, MC7912BT, MC7915BT, MC7918BT) share identical pinout (Pin 1: Ground, Pin 2: Input, Pin 3: Output) and package footprint. This allows direct substitution in existing designs when only output voltage differs, provided input voltage headroom and thermal design accommodate the new V_OUT.