MC34063ABD-TR - 1.5A Buck/Boost DC-DC Converter | STMicroelectronics
MPN: MC34063ABD-TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.62 | $0.62 |
| 10 | $0.52 | $5.20 |
| 100 | $0.41 | $41.00 |
| 500 | $0.35 | $175.00 |
| 1,000 | $0.29 | $290.00 |
MC34063ABD-TR Overview
A switching regulator IC is a power management device that converts one DC voltage level to another using switching elements (an internal transistor plus an external inductor and diode) rather than dissipative linear pass elements, achieving far higher efficiency. Within the power management hierarchy, the MC34063ABD-TR belongs to the DC-DC converter controller family, sitting below integrated modular converters but above bare PWM controllers because it integrates the oscillator, comparator, reference, and output switch in one die.
Key features include an internal temperature-compensated 1.25V reference with 2% accuracy, a duty-cycle-controlled oscillator operating up to 100 kHz, active current limiting via the Ipk sense pin, and low 2.5 mA typical quiescent current. These specifications make it suitable for battery-powered and cost-sensitive designs where a full-featured modern controller is unnecessary.
Architecturally, the device combines a comparator, gated oscillator latch, driver, and high-current Darlington output switch. Output voltage is set by two external resistors dividing the output down to the 1.25V reference at the comparator input, enabling step-down, step-up, or voltage-inverting converter configurations with minimal external components.
Typical applications include automotive USB charger adapters stepping 12V or 24V down to 5V, negative voltage rails for op-amp supplies in industrial instrumentation, and boost conversion from single-cell or low-voltage supplies in consumer products.
Design consideration: keep the oscillator timing capacitor and current-sense resistor values consistent with peak current requirements, and place the inductor and catch diode close to the IC to limit switching loop area; the device tolerates board-level noise well but efficiency drops at higher output currents.
This page synthesizes distributor pricing, drop-in alternatives across ST, onsemi, and Texas Instruments, and practical design notes not found in the manufacturer datasheet, with pricing referenced as of 2026-10-12.
Drop-in alternatives for MC34063ABD-TR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC34063ACD-TR
✅ Drop-In📋 Reference alternative (not in catalog)
MC33063ABD
✅ Drop-In📋 Reference alternative (not in catalog)
MC33063ADX
✅ Drop-In📋 Reference alternative (not in catalog)
MC34063ADR
✅ Drop-In📋 Reference alternative (not in catalog)
MC34063ADG4
✅ Drop-In📋 Reference alternative (not in catalog)
MC34063ABD-TR Maximum Ratings & Electrical Characteristics
| Topology | Buck, Boost, Inverting |
| Output Polarity | Positive or Negative |
| Output Type | Adjustable |
| Reference Voltage | 1.25 V |
| Reference Accuracy | 2 % |
| Input Voltage Range | 3 V to 40 V |
| Output Voltage Range | 1.25 V to 38 V |
| Switch Current | 1.5 A |
| Number of Outputs | 1 |
| Switching Frequency | Up to 100 kHz |
| Quiescent Current | 2.5 mA (typ) |
| Current Limiting | Active (cycle-by-cycle via Ipk sense) |
| Package | 8-SOIC (0.154 in, 3.90 mm width) |
| Mounting Type | Surface Mount |
| Operating Temperature | 0C to 70C (commercial grade A suffix) |
| Internal Reference | Temperature compensated |
MC34063ABD-TR Pin Configuration
| Pin 1 | Switch Collector — Collector of internal NPN output switch |
| Pin 2 | Switch Emitter — Emitter of internal NPN output switch |
| Pin 3 | Timing Capacitor — Oscillator timing capacitor connection, sets switching frequency |
| Pin 4 | GND — Ground |
| Pin 5 | Comparator Inverting Input — Feedback input from output voltage divider (reference 1.25 V) |
| Pin 6 | VCC — Supply voltage input, 3 V to 40 V |
| Pin 7 | Ipk Sense — Peak current limit sense input |
| Pin 8 | Driver Collector — Collector of internal driver stage |
Typical Applications
MC34063ABD-TR is suitable for 6 applications: Automotive USB Charger Adapter, Negative Rail Generation for Op-Amps, Boost Converter for Battery-Powered Devices, Industrial 24V to 5V Logic Supply, Set-Top Box and Consumer Appliance Standby Power, LED Driver and Lighting Bias Supply.
Automotive USB Charger Adapter
The MC34063ABD-TR is the classic regulator for in-vehicle USB chargers converting a 12V or 24V automotive supply down to a regulated 5V. Its 3V to 40V input tolerance absorbs car-battery cranking dips and load-dump-adjacent transients without additional front-end regulation, and the 1.5A internal switch supports a 1A USB output in buck configuration. The circuit needs only an inductor, Schottky catch diode, current-sense resistor, and timing capacitor, keeping bill-of-materials cost extremely low, which matters in high-volume accessory markets. Using the Ipk sense pin to set peak current around 1.2A-1.5A protects the switch during output shorts, and the 100 kHz maximum frequency keeps the inductor physically small enough for charger enclosure form factors.
Recommended
Negative Rail Generation for Op-Amps
In single-supply industrial and audio systems, the MC34063ABD-TR in the inverting topology generates -5V, -12V, or -15V rails for op-amps, comparators, and ADC drivers from a single positive input. The datasheet inverting circuit rearranges the inductor and catch diode so the switch pumps energy to a negative output node; because the device senses feedback relative to ground, the same 1.25V reference and 2% accuracy apply. Its 40V input ceiling and adjustable output accommodate common ±12V/±15V analog supply combinations from a 12V or 24V rail. Designers should derate output current in inverting mode, since switch stress is higher than in buck, and select a low-ESR output capacitor to control output ripple on the sensitive analog rail.
Recommended
Boost Converter for Battery-Powered Devices
The MC34063ABD-TR boosts low battery voltages, such as 3V from two alkaline cells or a lithium cell, to 5V or 12V for displays, sensors, and radios in portable and IoT products. In boost configuration the internal 1.5A switch charges the inductor during on-time and the output capacitor catches the discharge through the Schottky diode during off-time. The 2.5 mA typical quiescent current is acceptable for devices with intermittent operation or mains charging. The adjustable feedback divider lets designers target any voltage between 1.25V and 38V, making one regulator design reusable across product families. Frequency selection near 50-100 kHz keeps inductor size small while limiting switching losses inherent to this bipolar-process device.
Recommended
Industrial 24V to 5V Logic Supply
Factory automation and building-control boards frequently need a low-cost 5V logic rail from a 24V industrial bus. The MC34063ABD-TR handles this directly in buck mode with generous headroom below its 40V maximum input, tolerating unregulated wall supplies and long cable drops. Compared with a linear regulator dissipating (24V-5V) x load current as heat, the switching topology raises efficiency dramatically at, for example, 200 mA loads, reducing enclosure heating and eliminating heatsinks. Designers should size the inductor saturation current above the Ipk set point and verify loop stability with the recommended compensation values from the datasheet application section, as this family has no internal soft-start on hot plugging.
Recommended
Set-Top Box and Consumer Appliance Standby Power
Consumer appliances need a small always-on standby rail that remains economical at very high manufacturing volumes. The MC34063ABD-TR, priced around $0.30 at 1000-piece quantities as of 2026-10-12, provides that low-cost regulated standby supply from a mains-adapter DC input, delivering 5V or 3.3V to microcontroller and IR-receiver circuitry in buck configuration. The SOIC-8 surface-mount footprint supports automated assembly, and the mature multi-source ecosystem (ST, onsemi, Texas Instruments pin-compatible equivalents) protects production against allocation. Because standby efficiency targets are modest in legacy appliance designs, the device's simplicity and proven field reliability outweigh its lower efficiency compared with modern regulators.
Recommended
LED Driver and Lighting Bias Supply
The MC34063ABD-TR can bias LED strings or supply LED-driver controllers in lighting products, using the boost topology to raise a low-voltage DC input to the forward-voltage sum of a short LED chain. The active current-limit circuit protects the switch when the output is overloaded or shorted, and the adjustable output via the external resistor divider covers typical 12V or 24V LED strip rails from 5V or 12V inputs. Because LED brightness tolerance is loose, the 2% reference accuracy is more than adequate. Designers should note that this part provides voltage regulation rather than true constant-current drive, so a series current-setting resistor or downstream constant-current stage is required for precise LED current control.
Recommended
Recommended Products Summary
Engineering reference data for MC34063ABD-TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC34063ACD-TR | MC33063ABD | MC34063ADR | MC34063ADG4 |
|---|---|---|---|---|---|
| Package | SOIC-8 | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same |
| Brand | STMicroelectronics | STMicroelectronics | onsemi | Texas Instruments | Texas Instruments |
| Input Voltage Range | 3 V to 40 V | 3 V to 40 V | 3 V to 40 V | 3 V to 40 V | 3 V to 40 V |
| Switch Current | 1.5 A | 1.5 A | 1.5 A | 1.5 A | 1.5 A |
| Reference Accuracy | 2 % at 1.25 V | 2 % at 1.25 V | 2 % at 1.25 V | 2 % at 1.25 V | 2 % at 1.25 V |
| Max Switching Frequency | 100 kHz | 100 kHz | 100 kHz | 100 kHz | 100 kHz |
| Quiescent Current (typ) | 2.5 mA | 2.5 mA | 2.5 mA | 2.5 mA | 2.5 mA |
| Operating Temperature | 0C to 70C (commercial) | -40C to +125C | -40C to +125C | 0C to 70C | -40C to +125C |
Key Differentiators
- Ultra-low total solution cost with minimal external parts (vs MC34063ADR (Texas Instruments))
- Extended-temperature drop-in option within the same ST family (vs MC34063ACD-TR)
- Three topologies from one IC: buck, boost, and inverting (vs MC33063ABD (onsemi))
Design Notes
The 1.5A rating is the internal switch peak current, not continuous output current. For a buck converter at 12V input / 5V output, practical continuous output is typically near 1A depending on inductor choice and thermal budget. Set the peak current limit via the Ipk sense resistor (Rsc = 0.3 V / Ipk per the datasheet formula) and verify inductor saturation current exceeds the set peak by at least 20%. Use a Schottky catch diode; a standard silicon diode adds roughly 0.4-0.6 V extra drop and can reduce efficiency by more than 10 percentage points.
Keep the switching loop (Switch Collector/Switch Emitter pins, catch diode, and inductor) as small as possible to limit EMI radiated at the 30-100 kHz switching rate and its harmonics. Place the timing capacitor close to pin 3 and the feedback divider close to pin 5, routing the feedback trace away from the inductor and diode to avoid coupling switching noise into the 1.25V comparator input, which causes output jitter. Use a solid ground connection at pin 4 and star-ground the compensation components for stable regulation.
Oversizing the timing capacitor drives the oscillator far below 20 kHz, producing audible whine from the inductor. Undersizing it pushes switching losses up and reduces efficiency because this bipolar-process device has relatively slow transition edges. Also avoid omitting the output filter capacitor ESR check: the MC34063A loop relies on modest output ripple, and ultra-low-ESR ceramic output capacitors alone can destabilize the regulation loop; a small series resistor or a low-ESR electrolytic/tantalum is often more stable than pure MLCC output.
Estimated: at 12V input, 5V/500 mA output in buck mode with ~85% efficiency, dissipation is roughly 0.44 W in the IC and diode combined. The SOIC-8 package theta-JA of about 100-160 C/W (board-dependent; exact value in the manufacturer datasheet) yields a modest junction rise at this level, but at 1A output the rise can approach or exceed 100 C in still air, so increase copper pour area on the ground pins and verify junction temperature stays within the 0C to 70C commercial rating of the AB grade.
Compliance Information
Compliance data was not explicitly present in the verified web data. RoHS/REACH status should be confirmed on the ST product page before qualification. The MC34063ACD grade is the extended-temperature variant; AEC-Q100 qualification is not claimed for this part in the provided data.
