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onsemi KA34063AD
- Part No.:
- KA34063AD
- Manufacturer:
- onsemi
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
KA34063AD.pdf
- Description:
- IC REG BUCK BOOST ADJ 1.5A 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,994
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Product details
Overview
KA34063AD from onsemi (formerly Fairchild) is a monolithic DC-DC switching regulator controller IC used for step-up, step-down, and inverting converter topologies. It integrates a temperature-compensated 1.24 V bandgap reference, oscillator with 100 Hz–100 kHz frequency range, current-limit comparator, and 1.5 A output switch. It operates from 3.0 V to 40 V input and supports adjustable output voltage in power supply designs for industrial instrumentation and embedded systems.
For engineers reviewing the KA34063AD datasheet, pinout, applications, or equivalent options, key selection considerations include its internal 1.5 A switch capability, 300 mV current-sense threshold, oscillator timing current ratio (K = 5.2–7.5), saturation voltage under load (VCE(SAT)2 ≤ 0.7 V at 1.0 A), and 8-SOP package compatibility with legacy 34063 layouts.
Technical Context
The KA34063AD implements a fixed-frequency, current-mode control architecture using an internal oscillator whose frequency is set by external RT/CT. The device senses peak switch current via an external sense resistor connected to the IPK SENSE (Pin 5) terminal and compares it to a 300 mV threshold to terminate each switching cycle.
Its internal driver stage directly controls the NPN output transistor (Q1/Q2 Darlington pair), enabling operation without external transistors up to 1.5 A. The COMP (Pin 5) pin serves as both current-sense input and error amplifier inverting input, supporting feedback loop compensation through external RC networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.0 V to 40 V - supports wide-input industrial and automotive battery-derived supplies |
| Output Switch Current | 1.5 A - enables direct drive of power stages without external pass transistors |
| Current Sense Threshold | 300 mV (typ.) - sets overcurrent limit with ±50 mV tolerance; defines minimum sense resistor value |
| Oscillator Frequency Range | 100 Hz to 100 kHz - allows optimization of efficiency vs. size for inductor/capacitor selection |
| Reference Voltage | 1.24 V (typ.) - stable bandgap reference used for output voltage feedback divider design |
| Supply Current | 4.0 mA (max) - low quiescent draw suitable for battery-backed or standby-power-sensitive systems |
| Switch Saturation Voltage | 0.7 V (max at 1.0 A) - determines conduction loss and thermal rise in high-current operation |
Pinout & Package
KA34063AD is housed in an 8-pin Small Outline Package (8-SOP), measuring 4.92 mm × 6.00 mm × 1.55 mm, with 1.27 mm pitch and gull-wing leads. It is RoHS-compliant and rated for 0°C to +70°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (SW) | Switch Collector | High-current output node connecting to external inductor; carries pulsed 1.5 A peak current |
| Pin 2 (GND) | Ground Reference | Power and signal ground return for oscillator, reference, and comparator circuits |
| Pin 3 (VCC) | Supply Input | Primary power rail input (3–40 V); powers internal circuitry and drives output switch base |
| Pin 4 (CT) | Oscillator Timing Capacitor | Connects external capacitor to set oscillator frequency; discharge/charge currents define fOSC |
| Pin 5 (IPK SENSE / COMP) | Current Sense & Error Amp Inverting Input | Senses voltage across external sense resistor; also accepts feedback signal for regulation loop |
| Pin 6 (VREF) | Internal Reference Output | Provides 1.24 V reference for feedback divider; requires bypass capacitor for stability |
| Pin 7 (DISCHARGE) | Oscillator Discharge Terminal | Drives external timing capacitor during oscillator discharge phase; sets duty cycle |
| Pin 8 (OUTPUT) | Driver Output | Open-collector NPN output driving external transistor or internal switch base; not used when internal switch suffices |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 1.5 A switch | Eliminates need for external power transistors in sub-1.5 A DC-DC converters, reducing BOM count and layout area |
| Adjustable output voltage | Enabled by 1.24 V reference and external resistor divider - supports custom output levels from ~1.25 V upward |
| Short-circuit current limiting | Hardware-based protection triggered at 300 mV sense voltage - prevents thermal runaway during fault conditions |
| Low standby current | 2.7 mA typical supply current at light load - improves efficiency in intermittent-duty applications |
| Multi-topology support | Configurable as buck, boost, or inverting regulator using standard external components - increases design reuse |
Applications
| Industrial Power Supplies | Automotive Accessory Converters |
|---|---|
Use Scenario: Generating regulated 5 V or 12 V rails from unregulated 24 V industrial bus for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary DC-DC controller managing switching frequency, current limiting, and output regulation via feedback loop. Use Value: Enables compact, cost-effective isolated/non-isolated supplies with built-in overcurrent protection and wide input tolerance. | Use Scenario: Converting vehicle battery voltage (9–16 V) to stable 5 V for USB charging ports or infotainment peripherals. IC Role / Device Role / Timing Role: Step-down controller with internal switch handling peak loads up to 1.5 A without external MOSFETs. Use Value: Reduces component count and PCB footprint while maintaining robustness against cold-crank and load-dump transients. |
| Portable Instrumentation | Legacy System Retrofit |
Use Scenario: Providing dual-polarity ±5 V outputs from a single 9 V battery in handheld test equipment. IC Role / Device Role / Timing Role: Inverting regulator controller generating negative rail with precise current-limited switching. Use Value: Delivers reliable bipolar supply with minimal external parts, leveraging internal 1.24 V reference for accuracy. | Use Scenario: Replacing obsolete 34063 variants in field-deployed equipment where redesign is impractical. IC Role / Device Role / Timing Role: Pin-compatible drop-in replacement for KA34063A in 8-SOP footprint, preserving existing layout and bill of materials. Use Value: Maintains functional equivalence including oscillator timing, current sensing, and reference behavior across operating temperature range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC-DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC34063AP1G | Same core architecture; 1.25 V reference (vs. 1.24 V), slightly higher ICC (4.5 mA max), identical 8-DIP package | Requires board-level rework for SOP-to-DIP conversion; better availability but different thermal profile | Select when DIP mounting or legacy socket compatibility is required; verify reference tolerance impact on output accuracy |
| LM2574N-5.0 | Fixed 5 V output; no adjustable feedback; integrated 0.5 A switch; lower IQ (8 mA typ.); different pinout and topology constraints | Limited to step-down only; unsuitable for boost/inverting configurations or non-5 V outputs | Choose only for simple 5 V buck applications where adjustability and multi-topology flexibility are unnecessary |
Compared with MC34063AP1G and LM2574N-5.0, the KA34063AD offers unique value in adjustable-output, multi-topology designs within an 8-SOP footprint - making it optimal for space-constrained upgrades of legacy 34063-based systems where pin compatibility and function retention are critical.
Availability
KA34063AD is available at Aetrix Electronics and suitable for industrial power supplies, automotive accessory converters, and portable instrumentation requiring stable component supply and long-term obsolescence management.
Supply support for KA34063AD 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 Fairchild Semiconductor) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The KA34063AD belongs to the legacy 34063 family of monolithic DC-DC controllers designed for cost-sensitive, medium-power switching regulator applications where flexibility, simplicity, and proven reliability are prioritized over ultra-high efficiency or integration.
FAQ
What is the maximum output current supported by the KA34063AD without external transistors?
The KA34063AD supports up to 1.5 A peak switch current internally, as specified in its Absolute Maximum Ratings and Electrical Characteristics tables. This rating applies under pulsed test conditions to limit power dissipation. For continuous operation, thermal derating must be applied based on PCB copper area, ambient temperature, and airflow. The KA34063AD's internal Darlington switch enables this level of current without requiring external pass devices in many mid-power applications.
Does the KA34063AD support boost, buck, and inverting topologies?
Yes, the KA34063AD supports all three topologies - step-up (boost), step-down (buck), and inverting - using standard external component configurations documented in its application notes. Its flexible pinout, internal oscillator, and current-mode control architecture allow reconfiguration via changes to inductor placement, diode orientation, and feedback network connections. The KA34063AD's design explicitly targets multi-topology use, distinguishing it from fixed-function regulators.
What is the purpose of the DISCHARGE (Pin 7) terminal on the KA34063AD?
The DISCHARGE (Pin 7) terminal controls the oscillator's discharge phase by sinking current from the external timing capacitor (CT). Combined with the CHARGE current sourced from Pin 4 (CT), it establishes the oscillator's frequency and duty cycle. The ratio of discharge-to-charge current (K = 5.2–7.5) directly affects timing accuracy and ripple performance. Proper CT selection and PCB routing near Pin 7 are essential for stable KA34063AD operation across temperature and supply variations.
Is the KA34063AD recommended for new designs?
No - the KA34063AD is marked "DISCONTINUED" and "NOT RECOMMENDED FOR NEW DESIGN" in official onsemi documentation. While still available for legacy support and repair, new projects should consider modern alternatives such as the NCP3063 or LM2574 series for improved efficiency and thermal performance. Aetrix Electronics provides technical guidance and migration paths for customers transitioning away from the KA34063AD while maintaining functional equivalence.
How does the KA34063AD implement current limiting?
The KA34063AD implements cycle-by-cycle peak current limiting by monitoring voltage across an external sense resistor connected between Pin 5 (IPK SENSE) and ground. When this voltage reaches approximately 300 mV (typ.), the internal comparator triggers and terminates the current switching cycle. This hardware-based method provides fast, predictable overcurrent protection independent of feedback loop dynamics. The KA34063AD's current limit is fixed by its internal reference and does not require programming resistors or external comparators.
KA34063AD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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):
- -
- Voltage - Output (Max):
- -
- Current - Output:
- 1.5A (Switch)
- Frequency - Switching:
- 100Hz ~ 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
KA34063AD FAQ
1.How can I place an order for KA34063AD through Aetrix?
Please submit a Request for Quotation (RFQ) for KA34063AD 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 KA34063AD reliable?
The price and inventory of KA34063AD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KA34063AD is usually 5 days.
3.What payment methods are accepted for KA34063AD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KA34063AD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KA34063AD?
KA34063AD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KA34063AD 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 KA34063AD?
For technical support, including KA34063AD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KA34063AD requirements.
6.How does Aetrix verify that KA34063AD is sourced from the original manufacturer or authorized distributors?
All KA34063AD 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 KA34063AD meets industry standards.
7.What is the process for return or replacement of KA34063AD?
All KA34063AD units undergo pre-shipment inspection (PSI). If there is an issue with KA34063AD, 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 KA34063AD part is unused and in its original packaging.
Return procedure for KA34063AD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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