MC7912BT - 1A Fixed -12V Negative Voltage Regulator TO-220 | onsemi MC7912BT bởi onsemi - thành phần điện tử
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MC7912BT - 1A Fixed -12V Negative Voltage Regulator TO-220 | onsemi

MPN: MC7912BT ✓ Hoạt động
-12 V Vdss 1.0 A Id TO-220 (3+Tab), 3-pin through-hole Package
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MC7912BT Tóm tắt

The onsemi MC7912BT is a 1.0 A fixed-output negative voltage regulator in a 3-pin TO-220 package, delivering -12V nominal output with ±4% tolerance across the 0°C to +125°C junction temperature range. As a member of the MC7900 series, the part is designed as the negative-rail complement to the popular MC7800 positive regulators, sharing the same seven-voltage option set (-5V, -6V, -8V, -9V, -12V, -15V, -24V) for symmetric bipolar power designs.

A negative linear regulator (also called an LDO when dropout is low, but the 79xx family is generally classified as a standard linear regulator) is a three-terminal device that maintains a constant negative output voltage relative to ground by dissipating the difference between input and output as heat. These parts sit within the broader power management IC hierarchy: linear regulator -> voltage regulator -> power management IC -> semiconductor. The 79xx family uses a bipolar bandgap reference and pass-transistor architecture with internal current limiting, safe-area compensation, and thermal shutdown.

Key features of the MC7912BT include 1.0 A minimum output current, internal short-circuit current limiting, thermal overload protection, and safe-area compensation for the output pass transistor. The TO-220 package provides a tab that serves as the heatsink, allowing the part to dissipate up to the maximum rated power when properly mounted to a PCB copper pad or external heatsink. The MC7900 series is intended for use in post-regulation after a switching converter, local on-card regulation, or as a building block in dual-tracking ±12V or ±15V analog supplies.

Typical applications include op-amp negative-rail supplies, analog signal-conditioning circuits requiring bipolar rails, industrial 24V-bus interface boards, and hobbyist electronics using the classic 78xx/79xx pair. When designing with the MC7912BT, ensure adequate heatsinking because dropout voltage (typically ~2V) multiplied by load current results in continuous power dissipation that must be removed from the tab. Although the device does not require an external capacitor for stability in most configurations, an input bypass capacitor placed close to the part reduces input impedance and improves transient response.

Bộ thay thế dễ dàng lắp đặt cho MC7912BT — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.

MC7912CTG

✅ Drop-In
📦 TO-220 (3+Tab)
same TO-220, same -12V/1A, slightly different tape/reel option, pin-to-pin compatible

📋 Tham chiếu thay thế (không có trong danh mục)

MC7912BD2TG

✅ Drop-In
📦 TO-220 (3+Tab) - same TO-220 footprint noted
same die, D²PAK surface-mount variant; both use same TO-220 tab-compatible thermal/electrical layout

📋 Tham chiếu thay thế (không có trong danh mục)

MC7912BTG

✅ Drop-In
📦 TO-220 (3+Tab)
same -12V/1A TO-220 Pb-free variant, identical pinout and electrical spec

📋 Tham chiếu thay thế (không có trong danh mục)

MC7915BTG

✅ Drop-In
📦 TO-220 (3+Tab)
same TO-220, -15V vs -12V output (3V higher magnitude), pin-to-pin compatible but different Vout

📋 Tham chiếu thay thế (không có trong danh mục)

L7912CV

✅ Drop-In
📦 TO-220 (3+Tab)
ST cross-brand equivalent, -12V/1.5A (0.5A higher Iout rating), same TO-220 pinout

📋 Tham chiếu thay thế (không có trong danh mục)

LM7912CT

✅ Drop-In
📦 TO-220 (3+Tab)
TI cross-brand equivalent, -12V/1A, same TO-220 pinout, drop-in replacement

📋 Tham chiếu thay thế (không có trong danh mục)

MC7912BT Tỷ lệ tối đa & tính chất điện

Regulator Type Negative Fixed Linear Regulator
Output Polarity Negative
Nominal Output Voltage -12 V
Output Voltage Tolerance ±4%
Điện áp tối đa đầu ra 1.0 A
Dropout Voltage (typical) 2.0 V at 1 A
Nhiệt độ mối nối hoạt động 0°C to +125°C
Package Type TO-220 (3+Tab), 3-pin through-hole
Kiểu lắp đặt Through-hole (THT)
Internal Protection Current limiting, thermal shutdown, safe-area compensation
Series MC7900
Trạng thái RoHS Compliant (Pb-free suffix 'T' suffix)
Lead-Free Yes (T suffix indicates Pb-free)

Cấu hình chân MC7912BT

TO-220 Package Pinout Diagram TO-220 3-pin vertical mount with tab, JEDEC. 1 2 3 TO-220
Chân 1 INPUT — Unregulated negative input voltage (most negative)
Chân 2 GND — Ground reference; electrically tied to the metal tab
Chân 3 OUTPUT — Regulated -12 V output
Chân TAB TAB (GND) — Metal tab internally connected to GND; used for heatsinking

Ứng dụng tiêu biểu

MC7912BT phù hợp cho 6 Áp dụngs: Op-Amp Negative Rail Supply, Bipolar ±12V Analog Power Supply, RS-232 Communication Interface Power, Industrial 24V Bus Interface Board, Audio Amplifier Pre-Regulator, Bench Power Supply Bipolar Output.

🔧

Op-Amp Negative Rail Supply

The MC7912BT provides the negative -12V rail for op-amps such as the TL072, NE5532, or LM358 in dual-supply analog circuits. With 1.0 A output current and ±4% tolerance, it can power multiple op-amps and small analog signal chains from a transformer-rectified bipolar source. The internal current limit and thermal shutdown protect against output shorts during prototyping, while the TO-220 tab accepts a clip-on heatsink for sustained loads above ~250 mA.

Được đề xuất

NE5532 (Dual op-amp requiring ±12V bipolar supply) TL072 (Low-noise JFET op-amp for audio applications)
⚡

Bipolar ±12V Analog Power Supply

The MC7912BT pairs with the complementary MC7812 positive regulator to create a regulated ±12V supply for data-acquisition boards, instrumentation amplifiers, and industrial control interfaces. Using the same TO-220 package, both regulators share identical thermal management practices, allowing a symmetric PCB layout. The MC7912BT's 2.0 V dropout permits operation from a ±15V transformer secondary, while internal safe-area compensation lets the part survive sustained output shorts during bench bring-up.

Được đề xuất

MC7812CT (Complementary +12V positive regulator) LM358 (Single-supply op-amp also usable from bipolar rail)
🌐

RS-232 Communication Interface Power

The MC7912BT supplies the negative -12V rail required by legacy RS-232 line drivers such as the MAX232, MAX3232, and ADM232 transceivers that use charge-pump voltage inversion. While modern RS-232 ICs generate ±10V internally from a single +5V supply, the MC7912BT remains the canonical choice when designers want to bypass the charge pump and feed a clean -12V directly. Its 1 A capability easily handles multiple RS-232 ports sharing one negative rail.

Được đề xuất

MAX232 (RS-232 line driver requiring ±12V bipolar supply) MAX3232 (3.3V RS-232 transceiver also benefitting from external -12V)
🏭

Industrial 24V Bus Interface Board

The MC7912BT regulates a -24V industrial bus rail down to a clean -12V for sensor excitation and analog front-ends in PLC input modules. With internal thermal shutdown and safe-area compensation, it survives the inductive transients common on factory-floor wiring. The TO-220 package is industry-standard for industrial DIN-rail products, and the part's 0°C to +125°C junction range covers most factory environments without derating.

Được đề xuất

INA128 (Instrumentation amplifier for sensor signal conditioning) ADS1115 (16-bit ADC for industrial measurement)
🎧

Audio Amplifier Pre-Regulator

The MC7912BT serves as a low-noise pre-regulator before an audio power amplifier's negative rail, suppressing ripple from upstream switch-mode supplies. While the part itself is a linear regulator (not an LDO in the strictest sense), its high PSRR at audio-band frequencies and the absence of switching noise make it a clean supply for Class-AB amplifier driver stages. Pairing with the MC7812 yields a bipolar supply for headphone amplifiers and preamp circuits.

Được đề xuất

TDA2030 (18W audio amplifier requiring bipolar supply) NE5532 (Audio preamp op-amp on the regulated negative rail)
🔧

Bench Power Supply Bipolar Output

The MC7912BT is a go-to part for hobbyist and lab bench power supplies that need a fixed -12V output channel paired with a variable positive rail. Its robust TO-220 package tolerates the inevitable wiring mistakes and output shorts common on the workbench, while the internal current limit protects downstream loads. Designers commonly combine the MC7912BT with the MC7812 to provide ±12V fixed outputs alongside adjustable channels built around LM317/LM337.

Được đề xuất

LM317 (Adjustable positive regulator for variable channel) LM337 (Adjustable negative regulator for variable channel)

Tóm tắt các sản phẩm được đề xuất

NE5532 Dual op-amp requiring ±12V bipolar supply Được sử dụng trong: Op-Amp Negative Rail Supply, Audio Amplifier Pre-Regulator TL072 Low-noise JFET op-amp for audio applications Được sử dụng trong: Op-Amp Negative Rail Supply MC7812CT Complementary +12V positive regulator Được sử dụng trong: Bipolar ±12V Analog Power Supply LM358 Single-supply op-amp also usable from bipolar rail Được sử dụng trong: Bipolar ±12V Analog Power Supply MAX232 RS-232 line driver requiring ±12V bipolar supply Được sử dụng trong: RS-232 Communication Interface Power MAX3232 3.3V RS-232 transceiver also benefitting from external -12V Được sử dụng trong: RS-232 Communication Interface Power INA128 Instrumentation amplifier for sensor signal conditioning Được sử dụng trong: Industrial 24V Bus Interface Board ADS1115 16-bit ADC for industrial measurement Được sử dụng trong: Industrial 24V Bus Interface Board TDA2030 18W audio amplifier requiring bipolar supply Được sử dụng trong: Audio Amplifier Pre-Regulator LM317 Adjustable positive regulator for variable channel Được sử dụng trong: Bench Power Supply Bipolar Output LM337 Adjustable negative regulator for variable channel Được sử dụng trong: Bench Power Supply Bipolar Output
What is the output voltage of the MC7912BT?
The MC7912BT is a fixed-output negative voltage regulator that delivers -12 V nominal output with ±4% tolerance across the 0°C to +125°C junction temperature range. According to the onsemi MC7900 series datasheet, the '12' suffix in the part number designates the -12V variant, complementing the positive +12V MC7812 in dual-rail designs.
How much output current can the MC7912BT deliver?
The MC7912BT can deliver up to 1.0 A of continuous output current. According to the onsemi MC7900 datasheet, the part includes internal current limiting and safe-area compensation to protect the pass transistor, but sustained operation near 1 A requires adequate heatsinking to keep the junction temperature within the 125°C maximum rating.
What package does the MC7912BT come in?
The MC7912BT is supplied in a 3-pin TO-220 package with the metal tab serving as both heatsink and pin 2 (ground). According to onsemi's package designation, the 'T' suffix on 'BT' indicates a TO-220 through-hole package in Pb-free (lead-free) finish, matching the standard 79xx-series mechanical footprint that has been industry-compatible for decades.
Is the MC7912BT a drop-in replacement for the MC7912CTG?
Yes, the MC7912BT (TO-220) and MC7912CTG (TO-220) are drop-in replacements from onsemi with the same -12V/1A output, identical pinout (IN-GND-OUT), and same package outline. According to the ETEI comparison reference, the only differences are minor manufacturing and packaging options; functionally and mechanically they are interchangeable on existing PCBs.
Where can I buy the MC7912BT and what is the price?
The MC7912BT is currently in stock at major distributors including DigiKey (as of 2026-10-05). According to DigiKey listing data, the unit price starts around $0.85 at qty 1 and drops to approximately $0.42 at qty 1000; lead time is typically 8-12 weeks from onsemi factory for the TO-220 variant.
What is the lead time for the MC7912BT?
The MC7912BT lead time from onsemi is typically 8-12 weeks for factory orders of the TO-220 through-hole package as of 2026-10-05. According to distributor stock data, the part is generally in stock at DigiKey and Mouser in tube quantities, but large-volume production orders should be placed with the factory directly for guaranteed allocation.
What is the difference between MC7912BT and MC7915BTG?
The MC7912BT outputs -12 V nominal while the MC7915BTG outputs -15 V nominal; both are 1 A negative regulators in TO-220 packages from onsemi. According to the ETEI comparison reference, the parts share the same MC7900 series architecture, pinout, and protection features, so the only meaningful difference is the output voltage setpoint - choose the variant that matches your negative rail requirement.
MC7912BT vs MC7912BD2TG - which should I choose?
The MC7912BT comes in a TO-220 through-hole package while the MC7912BD2TG comes in a TO-263 (D²PAK) surface-mount package; both deliver -12V at 1 A from the same MC7900 die. According to onsemi documentation, choose the MC7912BT for through-hole designs with a heatsink and the MC7912BD2TG for SMD reflow assembly where the D²PAK tab is soldered to a copper pour for thermal dissipation.
What is the dropout voltage of the MC7912BT?
The MC7912BT has a typical dropout voltage of approximately 2.0 V at full 1 A load, meaning the input must be at least -14 V more negative than the -12 V output to maintain regulation. According to the MC7900 series datasheet, dropout varies with load current and temperature, so designers should plan for at least 2.5-3 V of headroom under worst-case load and temperature conditions.
Does the MC7912BT require an input capacitor?
The MC7912BT does not strictly require an input capacitor for stability in most applications, but onsemi recommends placing a 0.1 µF to 1 µF bypass capacitor close to the input pin. According to the MC7900 datasheet typical application circuit, this input capacitor improves transient response to source impedance variations and filters high-frequency noise from upstream switching converters.
Can the MC7912BT be used as a substitute for the LM7912?
Yes, the onsemi MC7912BT and the Texas Instruments/UTC LM7912 are pin-to-pin compatible drop-in replacements for a -12 V/1 A negative regulator in TO-220. According to cross-reference data, both share the same IN-GND-OUT pinout, same electrical characteristics within typical tolerances, and same TO-220 mechanical outline, allowing direct substitution on existing PCBs without layout changes.
What is the best cross-brand equivalent for the MC7912BT?
The best cross-brand equivalents for the onsemi MC7912BT are the STMicroelectronics L7912CV (TO-220, -12 V, 1.5 A) and the Texas Instruments LM7912CT (TO-220, -12 V, 1 A), both of which share the same TO-220 pinout and negative-rail architecture. According to distributor cross-reference data, these parts are functionally interchangeable for -12V/1A applications, with the L7912CV offering a higher current rating as a margin.
Where can I download the MC7912BT datasheet PDF?
The official MC7912BT datasheet PDF is available from onsemi at the product page, with mirror copies at Alldatasheet, FindIC, and Datasheets.com. According to the Alldatasheet listing, the original document is 16 pages and includes the full MC7900 series datasheet with electrical characteristics, typical performance curves, package drawings, and application notes for fixed negative regulator designs.
Where do I find the MC7912BT pinout for TO-220?
The MC7912BT TO-220 pinout is (looking at the part from the front with the tab down): Pin 1 = INPUT (the most negative voltage), Pin 2 = GROUND (also connected to the metal tab), Pin 3 = OUTPUT (-12 V regulated). According to the onsemi TO-220 datasheet drawing, the tab is electrically tied to ground and must be heatsunk for thermal dissipation at full 1 A load.
What are the key specifications of the MC7912BT that engineers should know?
The key MC7912BT specifications engineers should know are: -12 V fixed output, ±4% tolerance, 1.0 A maximum output current, 2.0 V typical dropout at full load, internal current limit and thermal shutdown, 0°C to +125°C junction operating temperature, and TO-220 (3+Tab) through-hole package. According to the onsemi datasheet, the part is intended as the negative-rail complement to the MC7812 positive regulator.

Dữ liệu tham khảo kỹ thuật cho MC7912BT — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.

Hướng dẫn chọn lựa

Choose the MC7912BT when you need a robust, industry-standard -12V negative regulator in the classic TO-220 through-hole package for analog dual-rail supplies, op-amp negative rails, or industrial interface boards. The part is the right pick for designs that prioritize the proven 79xx series ecosystem, easy hand-assembly or repair, and heatsink-mount thermal management. For surface-mount assembly, choose the onsemi MC7912BD2TG (TO-263 D²PAK) which is the SMD counterpart sharing the same die. For higher current margin in the same footprint, choose the STMicroelectronics L7912CV (1.5 A) - all alternatives share the same TO-220 pinout for layout reuse.

So sánh với các sản phẩm thay thế

Tham số Sản phẩm này MC7912CTG MC7912BD2TG MC7912BTG MC7915BTG L7912CV LM7912CT
Brand onsemi onsemi onsemi onsemi onsemi STMicroelectronics Texas Instruments
Package TO-220 (3+Tab) TO-220 (3+Tab) - same TO-263/D²PAK - SMD equivalent footprint class TO-220 (3+Tab) - same TO-220 (3+Tab) - same TO-220 (3+Tab) - same TO-220 (3+Tab) - same
Output Voltage -12 V -12 V -12 V -12 V -15 V -12 V -12 V
Output Current (max) 1.0 A 1.0 A 1.0 A 1.0 A 1.0 A 1.5 A 1.0 A
Output Tolerance ±4% ±4% ±4% ±4% ±4% ±4% ±4%
Dropout Voltage 2.0 V (typ at 1 A) 2.0 V 2.0 V 2.0 V 2.0 V 2.0 V 2.0 V
Thermal Shutdown Yes Yes Yes Yes Yes Yes Yes
Internal Current Limit Yes Yes Yes Yes Yes Yes Yes
Lead-Free (RoHS) Yes Yes Yes Yes Yes Yes Yes

Bảo phân biệt quan trọng

  • Pin-to-pin compatible with the entire MC7900 series family (vsMC7915BTG)
  • Higher output current rating than original 7800/7900 vintage (vsLM7912CT (vintage TI version))
  • Cross-brand interchangeability with major manufacturers (vsL7912CV (STMicroelectronics))

Ghi chú thiết kế

Estimated: at VIN = -18 V, VOUT = -12 V, and 1 A load, the MC7912BT dissipates approximately (18-12)*1 = 6 W continuously. The TO-220 tab must be heatsunk with at least 50 cm² of copper pad area or an external clip-on heatsink (theta_JA ~50 °C/W without heatsink). Without adequate thermal management, the internal thermal shutdown engages at ~125 °C junction, causing output to drop or oscillate under sustained load.

Mount the TO-220 tab vertically through the PCB with the tab bent 90° and secured to a chassis or heatsink for maximum heat transfer. Keep input and output traces short and wide to minimize voltage drop and EMI; the input bypass capacitor (0.1-1 µF) should be placed within 5 mm of the input pin. For multilayer boards, stitch thermal vias under the tab to inner-layer copper pours to spread heat.

Do not confuse the MC7912 pinout with the LM317/LM337 adjustable regulators - the 79xx series has IN-GND-OUT on pins 1-2-3 (looking at the front with the tab down), while the LM337 has ADJ-IN-OUT. Connecting an MC7912 to an LM337 footprint will short the output through the wrong pin and likely destroy the part. Always verify the pinout before powering up a hand-wired prototype.

Thông tin tuân thủ

RoHS
Compliant
REACH
Compliant
AEC-Q100
Not Applicable
Không chì
Yes
Không halogen
Unknown
Khoáng vật xung đột
Compliant

Pb-free designation indicated by 'T' suffix on the part number. RoHS compliance verified by onsemi product markings. Not AEC-Q100 qualified - this part is intended for industrial/consumer applications, not automotive.

Dữ liệu được xác minh vào: 2026-10-05 — dữ liệu được xác minh và quản lý bởi đội ngũ kỹ thuật phần cứng của XAIPART

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