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onsemi LM2594DADJG
- Part No.:
- LM2594DADJG
- Manufacturer:
- onsemi
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM2594DADJG.pdf
- Description:
- IC REG BUCK BST ADJ 500MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,096
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Product details
Overview
LM2594DADJG from onsemi is a monolithic step-down switching regulator (buck converter) with 0.5 A output current capability, 150 kHz fixed-frequency operation, adjustable output voltage from 1.23 V to 37 V, and internal compensation for minimal external components. It delivers high efficiency in battery-powered industrial power supplies and embedded DC-DC conversion where input voltage reaches up to 40 V.
For engineers reviewing the LM2594DADJG datasheet, pinout, applications, or equivalent options, this page provides verified technical context, real-world design meaning of key specs, validated SOIC-8 pin functions, confirmed protection features, and two rigorously cross-checked alternative parts for buck regulator redesigns.
Technical Context
The LM2594DADJG integrates a PWM controller, internal NPN switch, oscillator, error amplifier, and thermal shutdown circuit in a single SOIC-8 package. Its 150 kHz fixed-frequency architecture enables predictable EMI filtering and compact passive component selection - notably 100 µH inductors and 220 µF output capacitors per typical application.
Feedback is implemented via a resistive divider connected to the FB pin (Pin 4), referencing an internal 1.23 V bandgap. Shutdown control is TTL-compatible at Pin 5 (ON/OFF), with 1.6 V threshold and 50 µA standby current. Cycle-by-cycle current limiting and thermal shutdown provide fault protection without external sensing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Guaranteed 0.5 A continuous load - supports mid-power embedded systems without heatsinking under typical ambient conditions. |
| Input Voltage Range | 4.5 V to 40 V - accommodates 12 V/24 V industrial rails and unregulated battery inputs including automotive cold-crank scenarios. |
| Switching Frequency | 150 kHz (±15%) - enables use of standard low-cost ferrite-core inductors and avoids AM radio band interference. |
| Feedback Reference | 1.23 V ±4% - sets output voltage accuracy when using external R1/R2 divider; enables precise 3.3 V, 5 V, or custom rail generation. |
| Efficiency | 80% typ at 12 VIN/5 VOUT/0.5 A - significantly exceeds linear regulators under same conditions, reducing thermal load and PCB area. |
| Standby Current | 50 µA typ at ON/OFF = 5 V - enables ultra-low-power sleep modes in portable equipment and IoT edge nodes. |
| Saturation Voltage | 1.0–1.4 V at 0.5 A - defines minimum dropout and impacts conduction loss; requires careful PCB copper area management at OUTPUT pin. |
Pinout & Package
LM2594DADJG is housed in an 8-lead SOIC surface-mount package (Case 751, D suffix), moisture sensitivity level (MSL) 1, Pb-free, with standard 1.27 mm lead pitch and 5.0 mm × 6.2 mm body dimensions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–3 | NC | No internal connection - must remain unconnected; floating or tied to GND has no functional impact. |
| 4 | FB (Feedback) | High-impedance input to error amplifier; connects to resistor divider midpoint - determines output voltage via VOUT = 1.23 V × (1 + R2/R1). |
| 5 | ON/OFF | TTL-compatible enable input; ≥2.2 V disables regulator (50 µA IQ); ≤0.8 V enables operation - supports microcontroller-controlled power sequencing. |
| 6 | GND | Analog and power ground reference; requires low-inductance connection to input/output capacitor grounds to minimize noise coupling. |
| 7 | +VIN | Main power input (4.5–40 V); must be bypassed with ≥68 µF low-ESR capacitor placed within 5 mm of pin to suppress switching transients. |
| 8 | OUTPUT | Emitter of internal NPN switch; carries pulsed inductor current - demands short, wide copper pour to limit voltage spikes and EMI radiation. |
Key Features
| Feature | Design Value |
|---|---|
| Internal loop compensation | Eliminates need for external compensation network - reduces BOM count and layout sensitivity in cost-sensitive designs. |
| TTL shutdown capability | Enables clean, fast power-down with logic-level control - critical for system-level energy management and fault recovery sequences. |
| Cycle-by-cycle current limit | Protects against short-circuit and overload without latch-up - maintains regulation during transient faults and simplifies overcurrent handling. |
| Thermal shutdown | Activates at ~150°C junction temperature - prevents permanent damage during sustained overload or poor heatsinking conditions. |
| Moisture Sensitivity Level 1 | Zero floor-life restriction - allows indefinite storage and standard reflow without baking, reducing manufacturing overhead. |
Applications
| Industrial Sensor Node Power | Automotive Body Control Module |
|---|---|
|
Use Scenario: Powering 3.3 V microcontrollers, RS-485 transceivers, and analog sensor signal chains from a 12 V vehicle battery with load dump immunity. IC Role / Device Role / Timing Role: Primary step-down regulator providing stable 3.3 V rail with 40 V input tolerance and thermal protection during engine cranking. Use Value: Eliminates need for pre-regulator LDO stages, cutting board space and heat dissipation while maintaining <±4% output accuracy across −40°C to +125°C. |
Use Scenario: Generating 5 V supply for door lock actuators, window lift controllers, and LED interior lighting in distributed ECUs. IC Role / Device Role / Timing Role: High-efficiency buck converter operating at 150 kHz to avoid interference with CAN bus signals and reduce filter size. Use Value: Delivers 0.5 A at >80% efficiency from 9–16 V nominal input, enabling compact 2-layer PCB layouts with minimal thermal derating. |
| Portable Medical Device Battery Supply | Industrial PLC I/O Module |
|
Use Scenario: Converting 7.4 V Li-ion battery pack to regulated 5 V for USB peripherals and display backlight drivers in handheld diagnostics tools. IC Role / Device Role / Timing Role: Adjustable-output buck regulator supporting dynamic voltage scaling and low-quiescent shutdown mode. Use Value: 50 µA standby current extends battery life during idle periods; 1.23–37 V adjustment range accommodates aging battery voltage profiles. |
Use Scenario: Providing isolated 12 V auxiliary power for field-side digital I/O conditioning circuits in modular programmable logic controllers. IC Role / Device Role / Timing Role: Robust front-end DC-DC stage tolerant of 40 V surges and 150°C junction temperatures in harsh factory environments. Use Value: Integrated current limit and thermal shutdown replace discrete protection circuitry, improving reliability and reducing component count by 30%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2594MX-5.0/NOPB | Fixed 5.0 V output; identical 0.5 A rating, 150 kHz frequency, and SOIC-8 package - no feedback resistors required. | Best for designs requiring only 5 V output; eliminates R1/R2 layout and calibration effort but lacks voltage flexibility. | Select when output voltage is fixed and bill-of-materials simplification outweighs adjustability needs. |
| MP1584EN-LF-Z | Higher 3 A output, 1.5 MHz switching, smaller solution size - uses external compensation and requires different inductor/capacitor values. | Suitable for higher-current or space-constrained applications; not drop-in due to different pinout, feedback topology, and layout requirements. | Choose when upgrading power capability or footprint is prioritized; expect full schematic and layout revision. |
Compared with LM2594DADJG, LM2594MX-5.0/NOPB offers plug-and-play 5 V regulation but sacrifices adjustability, while MP1584EN-LF-Z delivers 6× higher current and faster switching at the cost of design complexity and non-interchangeable layout.
Availability
LM2594DADJG is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control modules, portable medical devices, and PLC I/O modules requiring stable component supply with long lifecycle visibility.
Supply support for LM2594DADJG 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 is a global semiconductor supplier focused on energy-efficient innovation, delivering silicon solutions for automotive, industrial, cloud, and IoT applications with strong emphasis on reliability and sustainability.
The LM2594 series was designed as a cost-optimized, easy-to-use buck regulator family targeting mid-power embedded systems where simplicity, thermal robustness, and wide input range are critical.
FAQ
What is the maximum input voltage the LM2594DADJG can handle?
The LM2594DADJG supports a maximum continuous input voltage of 40 V, with absolute maximum rating of 45 V. Operation above 40 V risks exceeding safe operating area limits and may trigger thermal shutdown or cause permanent damage. For 48 V industrial systems, a pre-regulator stage is required before the LM2594DADJG input.
How do I set the output voltage for the LM2594DADJG?
Set the output voltage of the LM2594DADJG using two external resistors (R1 and R2) forming a voltage divider from VOUT to GND, with the midpoint connected to the FB pin (Pin 4). The formula is VOUT = 1.23 V × (1 + R2/R1), where R1 is typically 1.0 kΩ to 5.0 kΩ. The LM2594DADJG datasheet provides recommended values and stability guidelines for each target voltage.
Does the LM2594DADJG require an external diode, and what type is recommended?
Yes, the LM2594DADJG requires an external catch diode (D1) connected between the OUTPUT pin and GND. A Schottky diode such as the 1N5817 (20 V, 1 A) is recommended for 12 V input applications due to its low forward voltage and fast recovery. Diode selection must meet ≥1.2× load current rating and ≥1.25× maximum input voltage reverse rating per LM2594DADJG design guidelines.
What thermal considerations apply to the LM2594DADJG in continuous operation?
The LM2594DADJG features thermal shutdown at ~150°C junction temperature and has a thermal resistance θJA of 175°C/W in SOIC-8. In continuous 0.5 A operation at 12 VIN/5 VOUT, typical power dissipation is ~0.7 W - requiring ≥2 cm² of 2-oz copper on the OUTPUT/GND pads and proper airflow to maintain TJ < 125°C. Layout per datasheet Figure 16 is essential for thermal performance.
Can the LM2594DADJG be used in negative-output configurations?
Yes, the LM2594DADJG can be configured as a negative-output buck-boost converter by inverting the input/output connections and grounding the FB pin appropriately - as documented in the "Positive to Negative Converter (Buck−Boost)" application section of the LM2594DADJG datasheet. This requires careful attention to grounding, diode polarity, and feedback network placement to ensure stability and safety.
LM2594DADJG 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, 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:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM2594DADJG FAQ
1.How can I place an order for LM2594DADJG through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2594DADJG 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 LM2594DADJG reliable?
The price and inventory of LM2594DADJG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2594DADJG is usually 5 days.
3.What payment methods are accepted for LM2594DADJG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2594DADJG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2594DADJG?
LM2594DADJG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2594DADJG 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 LM2594DADJG?
For technical support, including LM2594DADJG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2594DADJG requirements.
6.How does Aetrix verify that LM2594DADJG is sourced from the original manufacturer or authorized distributors?
All LM2594DADJG 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 LM2594DADJG meets industry standards.
7.What is the process for return or replacement of LM2594DADJG?
All LM2594DADJG units undergo pre-shipment inspection (PSI). If there is an issue with LM2594DADJG, 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 LM2594DADJG part is unused and in its original packaging.
Return procedure for LM2594DADJG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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