Texas Instruments LM2825N-12

Overview

LM2825N-12 from Texas Instruments is a fixed-output 12V, 1A DC-DC buck converter in a 24-pin PDIP package, featuring ±4% output voltage tolerance, 87% typical efficiency at 24V_IN/0.5A, and integrated thermal shutdown and current limiting. It operates across −40°C to +85°C ambient and supports input voltages from 15V to 40V - ideal for industrial power distribution and embedded system pre-regulation.

For engineers reviewing the LM2825N-12 datasheet, LM2825N-12 pinout, LM2825N-12 application, or LM2825N-12 equivalent, key selection considerations include its 12V fixed output, 24-pin PDIP thermal profile (θ_JA = 30°C/W), no-external-components operation, TTL-compatible shutdown, and radiated EMI compliance to CISPR 22 Class B.

Technical Context

The LM2825N-12 integrates a PWM controller, power MOSFET, diode, inductor, and feedback network into a single 24-pin PDIP package. Its internal oscillator runs at 150 kHz, and it employs current-mode control with second-stage current limiting that reduces switching frequency under overload.

It delivers up to 0.75A continuous output at 12V across full temperature range (−40°C to +85°C), derating above 0°C per published curves. Input voltage must exceed V_OUT + 2V (i.e., ≥15V) for stable regulation, and output ripple is specified at 100 mV_p-p under 24V_IN/1A load conditions.

Key Specifications

Pinout & Package

LM2825N-12 uses a 24-pin plastic dual-in-line package (PDIP), package drawing NFL, dimensions 1.25 × 0.54 × 0.26 inches. Thermal performance relies on soldered leads acting as heat paths to PCB copper.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DC-DC buck converter applications.

Compared with LM2678-12 and TPS54160DGQ, the LM2825N-12 uniquely delivers fixed 12V regulation with zero external passive components, proven CISPR 22 Class B compliance, and through-hole manufacturability - making it the most direct solution for cost-sensitive, medium-current industrial power nodes.

Availability

LM2825N-12 is available at Aetrix Electronics and suitable for industrial power distribution, embedded system pre-regulation, and on-card switching regulator applications requiring stable component supply, long-lifecycle support, and RoHS-compliant through-hole packaging.

Supply support for LM2825N-12 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 leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in high-reliability power conversion ICs.

The LM2825 product line was designed specifically for simplified, high-density DC-DC conversion in industrial and embedded systems - prioritizing integration, EMI control, and ruggedized thermal performance over programmability.

FAQ

What is the maximum continuous output current for LM2825N-12 across its full temperature range?

The LM2825N-12 delivers up to 0.75 A continuously across −40°C to +85°C ambient temperature, as confirmed in the LM2825-12 Electrical Characteristics table. This derating reflects thermal limits of the 24-pin PDIP package; at 25°C and 24V_IN, peak current reaches 1.2 A minimum per the DC output current limit specification. Always consult Figure 22 and Figure 23 for precise derating versus input/output voltage and ambient temperature when designing with LM2825N-12.

Does LM2825N-12 require external components to operate at its rated 12V output?

No - the LM2825N-12 is a fully integrated buck converter and requires no external feedback resistors, inductor, diode, or controller components to deliver its fixed 12V output. Only optional input and output capacitors are recommended for stability and transient response; the standard test circuit in Figure 17 confirms operation with zero mandatory external passives. This distinguishes LM2825N-12 from controller-only ICs and enables rapid prototyping and high-reliability deployment.

How does the shutdown and soft-start functionality work on LM2825N-12?

The LM2825N-12 uses a single SD/SS pin for both functions: applying <0.6 V places the device in low-power standby (I_Q ≈ 65 μA), while >2.0 V enables normal operation with built-in soft-start. Adding a capacitor (0.1–1 μF) between SD/SS and GND controls the output voltage ramp rate, limiting inrush current - especially critical when powered from current-limited sources. This dual-mode control is internally implemented and requires no external timing circuitry, simplifying system power sequencing for LM2825N-12.

Is LM2825N-12 compliant with electromagnetic compatibility standards?

Yes - the LM2825N-12 meets CISPR 22 Class B radiated emission limits (≤37 dBμV/m at 230–1000 MHz, measured at 10 m), as verified in the datasheet's Radiated EMI section. Its integrated magnetics, optimized internal layout, and fixed 150 kHz switching frequency contribute to predictable, low-noise operation. No additional shielding or complex filtering is required for Class B compliance, making LM2825N-12 suitable for commercial and industrial equipment without added EMI mitigation cost.

What is the recommended PCB layout practice for thermal management of LM2825N-12?

For reliable thermal performance, the LM2825N-12 requires ≥2 in² of 1 oz. copper area connected to its GND and VIN pins - as specified by its θ_JA = 30°C/W rating. The "No Connect" pins (1, 2, 3, 4, 5, 6, 7, 18–24) should be tied to this copper pour solely for thermal conduction, not electrical connection. Avoid isolating the PDIP body; ensure all solder joints are robust and uniform. Refer to Figure 25 in the LM2825 datasheet for the validated single-sided through-hole layout supporting LM2825N-12.