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onsemi LM2594PADJG
- Part No.:
- LM2594PADJG
- Manufacturer:
- onsemi
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2594PADJG.pdf
- Description:
- IC REG BUCK BST ADJ 500MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,389
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Product details
Overview
LM2594PADJG from onsemi is a monolithic step-down switching regulator (buck converter) with internal 0.5 A power switch, 150 kHz fixed-frequency oscillator, and adjustable output voltage (1.23 V to 37 V). It integrates internal loop compensation, thermal shutdown, cycle-by-cycle current limiting, and TTL-compatible ON/OFF control - enabling compact, high-efficiency DC-DC conversion for industrial power supplies and embedded systems.
For engineers reviewing the LM2594PADJG datasheet, pinout, applications, or equivalent options, this page delivers verified technical context, real-world design meaning of key specs, validated SOIC-8 pin functions, confirmed alternatives with functional differences, and supply-chain support details specific to this Pb-free adjustable buck regulator.
Technical Context
The LM2594PADJG implements voltage-mode PWM control with a fixed 150 kHz internal oscillator and integrated NPN power switch emitter-output topology. Its feedback pin (FB) senses a resistor-divider voltage referenced to 1.23 V nominal, enabling precise output programming without external compensation components.
It features logic-level shutdown (ON/OFF pin threshold ≈1.6 V), cycle-by-cycle current limit (typ. 0.7 A peak), thermal shutdown at 150°C, and operates across −40°C to +125°C junction temperature. Input voltage range is 4.5 V to 40 V, supporting wide-input industrial and automotive pre-regulation applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Guaranteed 0.5 A continuous load current - supports mid-power point-of-load conversion without external current boosting. |
| Input Voltage Range | 4.5 V to 40 V - enables direct operation from 12 V/24 V industrial rails and battery inputs up to 36 V nominal. |
| Switching Frequency | 150 kHz (±15%) - allows use of standard low-cost 100 µH inductors and reduces EMI filtering burden vs. lower-frequency converters. |
| Feedback Reference | 1.23 V ±4% - sets output voltage via external resistor divider; tolerance directly impacts output accuracy under line/load variation. |
| Standby Current | 50 µA typical at shutdown - enables ultra-low quiescent power in battery-backed or always-on standby modes. |
| Saturation Voltage | 1.0–1.4 V at 0.5 A - defines conduction loss in internal switch; impacts efficiency especially at low output voltages. |
| Thermal Shutdown | Activates at 150°C junction temperature - provides fail-safe protection during overload or poor heatsinking conditions. |
Pinout & Package
LM2594PADJG is housed in an 8-lead SOIC surface-mount package (Case 751, MSL Level 1, Pb-free), with exposed pad not electrically connected. Pin layout follows standard SOIC-8 orientation (pin 1 marked).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–3 | NC | No internal connection - must remain unconnected; floating or tied to GND has no effect. |
| 4 | FB | Feedback input to error amplifier - connects to resistor divider midpoint; 1.23 V reference sets output voltage. |
| 5 | ON/OFF | TTL-compatible enable control - <1.6 V = ON; >2.2 V = OFF; 50 µA standby current when pulled high. |
| 6 | GND | Circuit ground reference - requires low-impedance PCB connection; serves as return for internal switch and bias currents. |
| 7 | +VIN | Positive input supply - accepts 4.5–40 V; requires local low-ESR bypass capacitor (e.g., 68 µF) near pin. |
| 8 | OUTPUT | Emitter of internal NPN switch - connects to inductor and catch diode anode; high di/dt node requiring minimal PCB copper area. |
Key Features
| Feature | Design Value |
|---|---|
| Internal Loop Compensation | Eliminates need for external compensation network - reduces BOM count and layout sensitivity in basic buck designs. |
| Adjustable Output (1.23–37 V) | Single part supports wide output range via two-resistor feedback divider - avoids stocking multiple fixed-output variants. |
| TTL Shutdown Interface | Direct microcontroller GPIO compatibility - enables system-level power sequencing without level-shifting circuitry. |
| Cycle-by-Cycle Current Limit | Protects internal switch during short-circuit or overload - limits peak switch current to ~0.7 A, preventing destructive failure. |
| Thermal Shutdown | Automatically disables regulator above 150°C junction - prevents permanent damage during sustained overloads or ambient overheating. |
Applications
| Industrial Power Supply | Automotive Pre-Regulator |
|---|---|
Use Scenario: 24 V vehicle battery powers 5 V MCU and sensors in engine control unit. IC Role / Device Role / Timing Role: Primary step-down regulator converting unregulated 9–36 V battery rail to stable 5 V. Use Value: 80% efficiency at 12 VIN/5 VOUT/0.5 A reduces heat dissipation vs. linear regulators; 40 V max input withstands load-dump transients. |
Use Scenario: 12 V automotive supply feeds isolated 3.3 V rail for infotainment SoC. IC Role / Device Role / Timing Role: High-efficiency pre-regulator feeding downstream low-noise LDO or isolated DC-DC. Use Value: 150 kHz switching enables small 100 µH inductor; adjustable output supports multiple downstream voltage requirements. |
| Embedded System Point-of-Load | Battery Charger Power Stage |
Use Scenario: Industrial PLC module requires 3.3 V from 12 V backplane. IC Role / Device Role / Timing Role: Compact, self-contained buck converter on main board with minimal external components. Use Value: Internal compensation and SOIC-8 footprint simplify layout; 0.5 A output meets typical FPGA/MCU core rail needs. |
Use Scenario: Li-ion battery charger uses adjustable output to set constant-voltage charge stage (e.g., 4.2 V). IC Role / Device Role / Timing Role: Programmable voltage source controlling charging profile via feedback resistors. Use Value: 1.23 V reference enables precise 4.2 V ±1% setting; ON/OFF pin allows charge enable/disable by host controller. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596ADJ | 3 A output current, 150 kHz, wider input (4–40 V), higher quiescent current (10 mA vs. 5 mA) | Better suited for higher-current loads (>0.5 A); larger thermal footprint required | Select when ≥1 A output or higher efficiency at full load is needed; verify PCB layout supports TO-220 or D2PAK package. |
| MP1584EN-LF-Z | 3 A output, 1.5 MHz switching, adjustable output, requires external compensation | Enables smaller magnetics and capacitors but increases design complexity and EMI filtering demands | Choose for space-constrained designs where 1.5 MHz allows <47 µH inductors; accept added compensation tuning effort. |
Compared with LM2594PADJG, LM2596ADJ offers 6× higher output current but requires larger thermal management, while MP1584EN-LF-Z achieves miniaturization at the cost of external compensation and higher-frequency EMI challenges - making LM2594PADJG optimal for robust, low-complexity 0.5 A buck conversion.
Availability
LM2594PADJG is available at Aetrix Electronics and suitable for industrial power supplies, automotive pre-regulators, and embedded point-of-load applications requiring stable component supply, long-term lifecycle support, and Pb-free compliance.
Supply support for LM2594PADJG 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 supplier focused on energy-efficient power management, analog, and sensing technologies for automotive, industrial, and cloud infrastructure markets.
The LM2594 series was designed as a cost-effective, easy-to-use monolithic buck regulator family targeting non-isolated DC-DC conversion in space- and BOM-constrained industrial and embedded systems.
FAQ
What is the maximum input voltage rating for LM2594PADJG?
The LM2594PADJG has an absolute maximum input voltage rating of 45 V, with guaranteed operation across 4.5 V to 40 V. Exceeding 45 V risks permanent damage. For automotive applications subject to load dump (up to 60 V), external clamping or pre-regulation is required before the LM2594PADJG input.
How do I calculate the output voltage of LM2594PADJG?
The LM2594PADJG output voltage is set by a resistor divider between VOUT and GND, connected to the FB pin. Use VOUT = 1.23 V × (1 + R2/R1), where R1 connects FB to GND and R2 connects VOUT to FB. R1 should be 1.0 kΩ to 5.0 kΩ; 1% metal-film resistors ensure stability.
Does LM2594PADJG require external compensation components?
No, the LM2594PADJG includes internal loop compensation. No external capacitors or resistors are needed for basic operation - only the feedback divider, input/output capacitors, inductor, and catch diode are required, simplifying design and reducing bill-of-materials cost.
What is the purpose of the ON/OFF pin on LM2594PADJG?
Pin 5 (ON/OFF) enables logic-controlled shutdown of the LM2594PADJG. Applying <1.6 V (or leaving open) enables regulation; applying >2.2 V disables switching and reduces total input current to ~50 µA. This allows system-level power sequencing and battery-saving sleep modes.
Can LM2594PADJG be used in negative-output configurations?
Yes - the LM2594PADJG can configure as a negative-output buck-boost converter by grounding the OUTPUT pin and connecting the inductor to VIN, per Figure 1 in the datasheet. Output polarity reverses, enabling VOUT = –1.23 V × (1 + R2/R1), useful for generating negative bias rails.
LM2594PADJG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost, Buck-Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.23V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 500mA
- Frequency - Switching:
- 150kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LM2594PADJG FAQ
1.How can I place an order for LM2594PADJG through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2594PADJG 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 LM2594PADJG reliable?
The price and inventory of LM2594PADJG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2594PADJG is usually 5 days.
3.What payment methods are accepted for LM2594PADJG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2594PADJG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2594PADJG?
LM2594PADJG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2594PADJG 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 LM2594PADJG?
For technical support, including LM2594PADJG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2594PADJG requirements.
6.How does Aetrix verify that LM2594PADJG is sourced from the original manufacturer or authorized distributors?
All LM2594PADJG 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 LM2594PADJG meets industry standards.
7.What is the process for return or replacement of LM2594PADJG?
All LM2594PADJG units undergo pre-shipment inspection (PSI). If there is an issue with LM2594PADJG, 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 LM2594PADJG part is unused and in its original packaging.
Return procedure for LM2594PADJG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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