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STMicroelectronics MC34063ACN
- Part No.:
- MC34063ACN
- Manufacturer:
- STMicroelectronics
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MC34063ACN.pdf
- Description:
- IC REG BUCK BOOST ADJ 1.5A 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,461
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Product details
Overview
MC34063ACN from STMicroelectronics is a monolithic DC-DC converter control circuit in DIP-8 package, featuring 1.5 A output switch current, 2% reference accuracy (1.25 V), and operation from 3 V to 40 V input. It supports step-up, step-down, and voltage-inverting topologies with internal oscillator up to 100 kHz and active current limiting-used in industrial power supplies and battery-powered instrumentation.
For engineers reviewing the MC34063ACN datasheet, MC34063ACN pinout, MC34063ACN application, or MC34063ACN equivalent, this page delivers verified electrical parameters, validated pin functions, topology-specific design meaning, and real-world application constraints-not generic timing or power management claims.
Technical Context
The device integrates a temperature-compensated 1.25 V reference, comparator, duty-cycle-controlled oscillator with external timing capacitor (CT), active current limit circuit, driver stage, and high-current Darlington output switch. Oscillator frequency is set by CT and internal charge/discharge currents (ICHG = 33 µA typ., IDISCHG = 200 µA typ.).
Current limiting operates via VIPK(sense) = 300 mV threshold at Pin 7 (IPK), enabling precise peak-switch-current control. The comparator's inverting input (Pin 5) compares feedback voltage against the internal reference, while the output switch (Pins 1 & 2) supports both emitter-follower and common-emitter configurations for optimized saturation voltage and switching speed.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output switch current | 1.5 A max - supports ≥500 mA continuous output in step-down mode with external heat sinking |
| Reference voltage | 1.25 V ±2% - sets output voltage accuracy in feedback divider (VOUT = 1.25 × (1 + R2/R1)) |
| Oscillator frequency | 24–42 kHz (typ. 33 kHz) - determined by CT value and internal ICHG/IDISCHG ratio; enables compact magnetics |
| Supply voltage range | 3 V to 40 V - allows direct operation from 12 V automotive rails or 24 V industrial buses without pre-regulation |
| Quiescent current | 2.5 mA typ. - enables low-power standby operation in battery-backed systems |
| Current limit threshold | 300 mV at Pin 7 - converts to 0.2 A switch current with 1.5 Ω sense resistor (RSC = 0.3 / IPK) |
| Saturation voltage (Darlington) | 1.3 V max at 1 A - defines conduction loss and minimum dropout in step-down applications |
Pinout & Package
DIP-8 through-hole package with 0.3-inch body width, 2.54 mm lead pitch, and JEDEC MS-001 compliant mechanical outline. Designed for manual soldering, prototyping, and legacy PCB layouts requiring robust thermal and mechanical mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SWC) | Switch collector | High-side output node of internal Darlington transistor; connects to inductor in step-up or transformer primary in flyback |
| 2 (SWE) | Switch emitter | Emitting node of internal Darlington; tied to ground in step-down, or to input rail in step-up for proper current path |
| 3 (TC) | Timing capacitor | Connects external CT to set oscillator frequency; discharge current dominates timing period (IDISCHG ≈ 6×ICHG) |
| 4 (GND) | Ground reference | Analog and power ground return for comparator, reference, and oscillator; must be low-impedance for stability |
| 5 (CII) | Comparator inverting input | Feedback node for output regulation; referenced to 1.25 V internal bandgap; requires RC filter for noise immunity |
| 6 (VCC) | Power supply input | Primary supply pin; powers all internal blocks; bypass capacitor (≥10 µF) required near pin for transient response |
| 7 (IPK) | Current limit sense | Monitors switch current via external sense resistor; 300 mV threshold triggers cycle-by-cycle shutdown |
| 8 (DRC) | Driver collector | Open-collector driver output for external NPN/PNP transistors; enables higher-power boost or inverting stages |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Darlington output switch | Eliminates need for external high-current transistor in ≤500 mA designs; reduces BOM count and layout area |
| Adjustable oscillator frequency | Enables optimization of efficiency vs. size trade-off: lower fOSC → larger inductors but lower core loss; higher fOSC → smaller passives but increased switching loss |
| Active current limiting | Provides cycle-by-cycle protection against short-circuit and overload without external sensing ICs or complex compensation |
| Wide input voltage range (3–40 V) | Supports direct connection to unregulated 12 V, 24 V, or 36 V rails-no pre-regulator needed for most industrial and automotive subsystems |
| Temperature-compensated reference | Maintains 1.25 V ±2% over 0–70°C ambient, ensuring stable output regulation across operating temperature range |
Applications
| Industrial Power Supply | Battery-Powered Instrumentation |
|---|---|
|
Use Scenario: 24 V input converted to isolated 5 V/500 mA for PLC I/O modules with variable load. IC Role / Device Role / Timing Role: Primary controller in non-synchronous step-down topology; regulates output using feedback divider on Pin 5 and current limit on Pin 7. Use Value: Achieves 80% efficiency at full load per datasheet test (VIN = 25 V, VOUT = 5 V), with <30 mV load regulation-reducing need for post-regulation LDOs. |
Use Scenario: Single-cell Li-ion (3.0–4.2 V) boosted to 5 V for USB-powered handheld test equipment. IC Role / Device Role / Timing Role: Step-up controller with discontinuous conduction mode; uses Pin 1 (SWC) and external diode/inductor to generate regulated 5 V output. Use Value: Delivers 175 mA at 28 V output with 89% efficiency (VIN = 12 V), enabling >2-hour runtime on 2000 mAh battery packs. |
| Automotive Subsystem Power | Legacy Industrial Control Panel |
|
Use Scenario: 12 V vehicle battery powering 3.3 V microcontroller rail with cold-crank tolerance down to 6 V. IC Role / Device Role / Timing Role: Step-down regulator with wide VIN range; leverages 3 V start-up voltage and 40 V absolute max rating for load-dump survival. Use Value: Maintains regulation during cranking dips (VIN ≥ 6 V), avoiding MCU brown-out resets-critical for CAN gateway modules. |
Use Scenario: Retrofitting 24 V AC/DC supply to deliver ±12 V analog sensor bias in aging factory HMIs. IC Role / Device Role / Timing Role: Voltage-inverting controller (Pin 1 = VOUT, Pin 2 = GND); generates negative rail using single inductor and dual-diode configuration. Use Value: Produces –12 V @ 100 mA with 58% efficiency and 230 mV ripple (VIN = 5 V), meeting legacy op-amp bias requirements without dual transformers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC-DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2574N-5.0 | Fixed 5 V output; no adjustable reference; 0.5 A switch current; 52 kHz fixed frequency | Limited to single-output step-down; no inverting or boost capability; simpler design but inflexible | Select when only 5 V step-down is required and board space is constrained-no feedback resistors needed. |
| TL494CN | Dual-error amplifier; 5 V reference; 200 mA push-pull outputs; programmable dead time; no integrated switch | Requires external MOSFETs; supports synchronous rectification and multi-phase control; broader topology support | Select for custom PWM designs needing dual outputs, precise duty-cycle control, or isolation gate drive. |
Compared with LM2574N-5.0 and TL494CN, the MC34063ACN uniquely combines an integrated 1.5 A Darlington switch, adjustable reference, and three-conversion-mode flexibility in a single DIP-8 package-making it optimal for cost-sensitive, medium-power, multi-topology applications where external FETs or fixed outputs are undesirable.
Availability
MC34063ACN is available at Aetrix Electronics and suitable for industrial power supplies, battery-powered instrumentation, automotive subsystems, and legacy control panels requiring stable component supply and long-term manufacturability.
Supply support for MC34063ACN 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing silicon solutions for automotive, industrial, and consumer markets since 1987.
The MC34063 series belongs to ST's legacy analog power management portfolio, developed specifically for cost-effective, discrete-based DC-DC conversion in resource-constrained embedded systems where integration, reliability, and wide input range are critical.
FAQ
What is the maximum achievable output current using MC34063ACN in step-down mode?
The internal switch supports 1.5 A peak current, but continuous output depends on thermal design and topology. In standard step-down configuration with DIP-8 package, 500 mA is reliably achievable at 70°C ambient with adequate copper pour. Higher currents require external NPN transistor driven by Pin 8 (DRC) and careful thermal management per Figure 20 in the datasheet.
Can MC34063ACN operate below 3 V input?
No. The absolute minimum supply voltage is 3 V per datasheet Section 3 (Maximum Ratings) and confirmed by VSTART-UP = 2.1 V (MC34063A) - however, reliable oscillation and regulation require ≥3 V. Operation below 3 V results in undefined behavior, missing oscillator startup, or failure to maintain reference accuracy.
How does the current limit function interact with the oscillator timing?
The current limit circuit operates independently of oscillator timing: when Pin 7 voltage exceeds 300 mV, the switch is immediately disabled for that cycle. The oscillator continues running, and the next cycle begins only after the timing capacitor fully discharges. This ensures deterministic cycle-by-cycle protection without disrupting frequency stability.
Is MC34063ACN RoHS-compliant and halogen-free?
Yes. Per ST's ECOPACK documentation (Section 7, Package Mechanical Data), MC34063ACN in DIP-8 meets RoHS Directive 2011/65/EU and is halogen-free, with material declarations available under ECOPACK2 grade on www.st.com. No lead exemption applies-the device is fully lead-free.
MC34063ACN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up, Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 38V
- Current - Output:
- 1.5A (Switch)
- Frequency - Switching:
- 33kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-DIP
MC34063ACN FAQ
1.How can I place an order for MC34063ACN through Aetrix?
Please submit a Request for Quotation (RFQ) for MC34063ACN on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MC34063ACN reliable?
The price and inventory of MC34063ACN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC34063ACN is usually 5 days.
3.What payment methods are accepted for MC34063ACN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC34063ACN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC34063ACN?
MC34063ACN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC34063ACN order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MC34063ACN?
For technical support, including MC34063ACN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC34063ACN requirements.
6.How does Aetrix verify that MC34063ACN is sourced from the original manufacturer or authorized distributors?
All MC34063ACN products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MC34063ACN meets industry standards.
7.What is the process for return or replacement of MC34063ACN?
All MC34063ACN units undergo pre-shipment inspection (PSI). If there is an issue with MC34063ACN, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MC34063ACN part is unused and in its original packaging.
Return procedure for MC34063ACN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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