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Texas Instruments LM2825N-ADJ/NOPB
- Part No.:
- LM2825N-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 24-DIP (0.600", 15.24mm)
- Datasheet:
-
LM2825N-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 1A 24PDIP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM2825N-ADJ/NOPB from Texas Instruments is a self-contained 1A synchronous buck DC-DC converter in a 24-pin PDIP package, delivering adjustable output voltages from 1.23V to 8V with ±4% tolerance, 74% typical efficiency at 12VIN/0.5A, and 65 μA standby quiescent current. It integrates all active and passive components for high-efficiency step-down regulation and is used in industrial power supplies requiring compact, reliable on-card conversion.
For engineers reviewing the LM2825N-ADJ/NOPB datasheet, LM2825N-ADJ/NOPB pinout, LM2825N-ADJ/NOPB application, or LM2825N-ADJ/NOPB equivalent, key selection criteria include its 4.5–40V input range, internal current limiting (1.2A min), thermal shutdown protection, TTL-compatible shutdown/soft-start control, and PDIP package suitability for through-hole prototyping and ruggedized embedded systems.
Technical Context
The LM2825N-ADJ/NOPB implements a fixed-frequency (150 kHz) current-mode PWM buck regulator with integrated power switch, error amplifier, oscillator, and protection circuitry. Its feedback loop uses an internal 1.23V reference applied to the ADJ pin, enabling precise output programming via external resistor dividers.
It features dual-stage overcurrent protection-first-stage foldback and second-stage hiccup mode-and combines thermal shutdown with junction temperature monitoring up to +125°C. The device operates across −40°C to +85°C ambient and supports programmable soft-start via external capacitor on the SS pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 1A maximum continuous load; derated above 0°C ambient per thermal curves |
| Input Voltage Range | 4.5V to 40V; enables direct use with 5V, 12V, 24V, and 36V industrial rails |
| Output Voltage Range | 1.23V to 8V; set externally via R1/R2 divider; VADJ = 1.23V ±2.7% |
| Efficiency | 74% typical at 12VIN, 0.5A, 3VOUT; reduces heat dissipation vs linear regulators |
| Quiescent Current | 65 μA in shutdown; enables low-power system sleep modes without auxiliary LDOs |
| Switching Frequency | 150 kHz fixed; simplifies EMI filtering design and avoids AM radio band |
| Thermal Resistance | 30°C/W junction-to-ambient (PDIP, 2 in² copper); defines heatsinking requirements |
Pinout & Package
The LM2825N-ADJ/NOPB is housed in a 24-pin plastic dual-in-line (PDIP) package (Package Drawing NFL), measuring 1.25 × 0.54 × 0.26 inches, with through-hole mounting and no exposed thermal pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 19, 20, 21, 22, 23, 24 | Ground | Common return path for power, control, and feedback; multiple pins reduce ground impedance |
| 8, 9 | Feedback Compensation | Shorting pins 8 and 9 reduces output ripple by 25–33%; requires feed-forward capacitor CFF |
| 10 | Adjust (ADJ) | Sense node for voltage divider; regulates output by maintaining 1.23V at this pin |
| 11 | Shutdown/Soft-start (SD/SS) | TTL-compatible input: <0.6V = shutdown (65 μA IQ), >2.0V = soft-start enabled |
| 12 | Output (VOUT) | Main regulated DC output; capable of sourcing up to 1A with proper layout and thermal management |
| 13 | Input (VIN) | Primary DC input; accepts 4.5–40V; requires local bypass capacitor if >6″ from bulk cap |
| 14, 15, 16, 17, 18 | No Connect (NC) | Internally unconnected; must remain electrically isolated but may be tied to ground for thermal relief |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Buck Power Stage | Eliminates need for external MOSFET, diode, and controller IC - reduces BOM count and layout complexity |
| Programmable Soft-Start | External capacitor on SD/SS pin controls ramp rate, preventing inrush current into downstream capacitance |
| Two-Stage Overcurrent Protection | Foldback + hiccup mode prevents thermal runaway during sustained overload or short-circuit conditions |
| Low-Ripple Adjustable Output | Shorting pins 8/9 + adding CFF achieves ≤30 mVp-p ripple at 1A, suitable for noise-sensitive analog circuits |
| Radiated EMI Compliance | Meets CISPR 22 Class B limits at 10 m - reduces need for external shielding or ferrite beads in end equipment |
Applications
| Industrial Sensor Node Power | Programmable Lab Supply Module |
|---|---|
Use Scenario: Powering 3.3V/5V microcontrollers, ADCs, and RS-485 transceivers in distributed field sensors operating from 24V DC rails. IC Role / Device Role / Timing Role: Primary buck regulator providing stable, low-noise 3.3V or 5V output; replaces discrete switching solutions with higher reliability. Use Value: Enables single-rail 24V-to-3.3V conversion with 74% efficiency and built-in thermal/current protection - eliminates external supervision circuitry. | Use Scenario: User-adjustable bench supply output (1.23–8V) with digital control interface and soft-start for lab test equipment. IC Role / Device Role / Timing Role: Core adjustable DC-DC stage; ADJ pin driven by DAC or potentiometer; SD/SS pin controlled by MCU GPIO. Use Value: Delivers precise, programmable voltage with <±4% tolerance and <100 mV p-p ripple - meets mid-range bench supply accuracy requirements without complex compensation. |
| On-Card Pre-Regulator for Linear Stages | Distributed Power in Control Cabinets |
Use Scenario: Generating 5.5V intermediate rail from 24V bus to feed low-noise LDOs powering precision op-amps and references. IC Role / Device Role / Timing Role: Efficient pre-regulator reducing dropout voltage and heat in downstream linear regulators. Use Value: Reduces power loss by >60% vs direct 24V-to-5.5V linear regulation; maintains tight line/load regulation (<8 mV) under dynamic loads. | Use Scenario: Local 5V/3.3V power for PLC I/O modules mounted inside metal enclosures with limited airflow. IC Role / Device Role / Timing Role: Standalone buck converter on each module PCB; PDIP package aids mechanical robustness and serviceability. Use Value: Operates reliably from −40°C to +85°C ambient with thermal shutdown; 30°C/W θJA allows conduction cooling via chassis mount. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576HVS-ADJ | Higher 60V max input; 3A output; TO-220 package; 52 kHz switching frequency | Better suited for high-input-voltage industrial systems (>40V) and higher current loads | Select when input exceeds 40V or output current >1A is required; requires heatsink and larger layout |
| TPS54202DRCR | 2A output; 6V max input; 400 kHz switching; SOIC-10 package; integrated FETs and compensation | Optimized for low-voltage, high-density designs where board space and efficiency at light loads matter | Select for compact 5V-input systems needing >1A and better light-load efficiency; not suitable for 24V+ inputs |
Compared with LM2825N-ADJ/NOPB, LM2576HVS-ADJ offers higher input voltage headroom and current capability at the cost of larger size and lower switching frequency, while TPS54202DRCR delivers higher integration and density for low-input applications but lacks the wide 4.5–40V range and rugged PDIP form factor.
Availability
LM2825N-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial sensor nodes, programmable lab supplies, on-card pre-regulators, and distributed control cabinet power systems requiring stable component supply and long-term manufacturability.
Supply support for LM2825N-ADJ/NOPB 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
Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and power management technologies, with decades of leadership in high-reliability power conversion ICs.
The LM2825 product line was designed for rugged, self-contained DC-DC conversion in industrial and embedded systems where minimal external components, wide input range, and through-hole assembly are critical requirements.
FAQ
What output voltage range does the LM2825N-ADJ/NOPB support?
The LM2825N-ADJ/NOPB supports an output voltage range of 1.23V to 8V, set by an external resistor divider connected to the ADJ pin. This range is confirmed in the LM2825-ADJ Electrical Characteristics table, where VADJ is specified as 1.230V ±2.7%, and the device is explicitly optimized for outputs between 1.23V and 8V per the APPLICATION INFORMATION section. The LM2825N-ADJ/NOPB does not support the 7–15V range - that applies only to the H-ADJ variant.
Does the LM2825N-ADJ/NOPB require external components to operate?
Yes, the LM2825N-ADJ/NOPB requires external components to operate: at minimum, an input capacitor (if >6″ from bulk source), output capacitor, and resistor divider (R1/R2) for output voltage setting. Unlike fixed-output versions, the LM2825N-ADJ/NOPB cannot function without the ADJ pin network. Optional components include a soft-start capacitor on the SD/SS pin and a feed-forward capacitor (CFF) if pins 8 and 9 are shorted to reduce ripple.
What is the maximum continuous output current of the LM2825N-ADJ/NOPB?
The LM2825N-ADJ/NOPB is rated for up to 1A of continuous output current under specified thermal and voltage conditions. However, actual deliverable current depends on ambient temperature, input/output voltage differential, and PCB copper area. Derating curves in Figures 20–23 show reduced output current at extremes: e.g., ≤0.75A at 85°C ambient or with high VIN/VOUT ratios. The guaranteed minimum DC output current limit is 1.2A per the Electrical Characteristics table.
How does the shutdown and soft-start functionality work on the LM2825N-ADJ/NOPB?
The LM2825N-ADJ/NOPB uses a single SD/SS pin for both functions: applying <0.6V places it in shutdown mode (IQ ≈ 65 μA), while applying >2.0V initiates soft-start. During soft-start, internal current ramps up gradually, controlling output voltage rise time. A capacitor on this pin sets the ramp duration - values from 0.1 μF to 1 μF are recommended. This dual-function pin simplifies control interface design while ensuring safe startup and low-power standby.
Is the LM2825N-ADJ/NOPB RoHS compliant and lead-free?
Yes, the LM2825N-ADJ/NOPB is RoHS compliant and lead-free. Per TI's PACKAGE OPTION ADDENDUM, the /NOPB suffix indicates "Green (RoHS & no Sb/Br)" packaging with CU SN (copper-tin) lead finish and Level-1 moisture sensitivity rating. It meets EU RoHS Directive 2011/65/EU requirements and contains no intentionally added bromine or antimony-based flame retardants.
LM2825N-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-DIP (0.600", 15.24mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- 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):
- 15V
- Current - Output:
- 1A
- Frequency - Switching:
- 150kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 24-PDIP
LM2825N-ADJ/NOPB FAQ
1.How can I place an order for LM2825N-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2825N-ADJ/NOPB 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 LM2825N-ADJ/NOPB reliable?
The price and inventory of LM2825N-ADJ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2825N-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2825N-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2825N-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2825N-ADJ/NOPB?
LM2825N-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2825N-ADJ/NOPB 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 LM2825N-ADJ/NOPB?
For technical support, including LM2825N-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2825N-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2825N-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2825N-ADJ/NOPB 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 LM2825N-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2825N-ADJ/NOPB?
All LM2825N-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2825N-ADJ/NOPB, 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 LM2825N-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2825N-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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