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Texas Instruments LM2597N-12
- Part No.:
- LM2597N-12
- Manufacturer:
- Texas Instruments
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2597N-12.pdf
- Description:
- IC REG BUCK 12V 500MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,831
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Product details
Overview
LM2597N-12 from Texas Instruments is a monolithic 150-kHz nonsynchronous step-down (buck) DC-DC converter delivering 0.5-A output current with fixed 12-V output, ±4% output voltage tolerance over line and load, 4.5–40-V input voltage range, and integrated shutdown/soft-start and error flag functions - used in industrial power supplies and embedded system point-of-load regulation.
For engineers reviewing the LM2597N-12 datasheet, LM2597N-12 pinout, LM2597N-12 application, or LM2597N-12 equivalent, key selection criteria include its fixed 12-V output, PDIP-8 package compatibility, 150-kHz switching frequency for compact filter design, bias supply (VBS) pin for efficiency optimization at high VIN/low VOUT, and thermal shutdown protection.
Technical Context
The LM2597N-12 implements a fixed-frequency current-mode control architecture with internal compensation, enabling stable operation with minimal external components. Its 150-kHz oscillator sets the switching period, while the internal power switch features 0.9–1.2-V saturation voltage and dual-stage current limiting (0.58–1.4-A peak) for fault robustness.
It integrates supervisory functions including an open-collector error flag that asserts low when output drops >5% below nominal, with programmable delay via external capacitor on the Delay pin. The Bias Supply (VBS) pin allows powering internal circuitry from VOUT instead of VIN - improving efficiency by up to ~3% at light loads and high input voltages (e.g., 25 V → 12 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V ±4% over full temperature and load range - ensures stable rail for microcontrollers and analog circuitry without external feedback resistors. |
| Max Output Current | 0.5 A DC - supports moderate-power loads such as sensors, logic rails, and peripheral ICs in industrial and telecom systems. |
| Input Voltage Range | 4.5 V to 40 V - compatible with 12-V, 24-V, and 36-V nominal bus systems, including automotive battery-supplied designs with transient margin. |
| Switching Frequency | 150 kHz (±15%) - enables use of standard off-the-shelf inductors (e.g., 68–100 µH) and reduces EMI compared to lower-frequency alternatives. |
| Quiescent Current | 5–10 mA operating, 85 µA standby - minimizes no-load power loss in always-on applications like remote monitoring nodes. |
| Thermal Protection | Internal thermal shutdown at 150°C junction temperature - prevents damage during overload or poor PCB heatsinking conditions. |
| Package | PDIP-8 (9.81 mm × 6.35 mm) - through-hole mounting suitable for prototyping, legacy industrial boards, and high-reliability manual assembly. |
Pinout & Package
LM2597N-12 is supplied in an 8-pin plastic dual in-line package (PDIP), with 2.54-mm lead pitch and standard through-hole footprint. Thermal resistance θJA = 150°C/W with typical PCB copper area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Error_Flag) | Open-collector output | Asserts low when VOUT falls >5% below 12 V; used for microprocessor reset or system fault signaling - requires external pull-up resistor. |
| 2 (Delay) | Capacitor connection node | Sets time delay between VOUT reaching 95% of 12 V and Error_Flag going high - enables controlled power-up sequencing. |
| 3 (Bias_Supply) | Power input for internal circuitry | Accepts 3.5–30 V; connecting to 12-V output improves efficiency at high VIN (e.g., 25 V → 12 V) by reducing internal regulator dissipation. |
| 4 (Feedback) | Regulation reference input | Internally tied to 1.23-V reference; unused in fixed-output version - must be left open or grounded per datasheet guidance. |
| 5 (Shutdown/Soft-Start) | Dual-function digital control | Pull ≤0.6 V to enter 85-µA standby mode; add capacitor for soft-start ramp - limits inrush current and avoids input rail collapse. |
| 6 (Ground) | Power and signal reference | Main return path for internal switch, control circuitry, and external components - requires low-impedance connection to minimize noise coupling. |
| 7 (+VIN) | Main power input | Accepts 4.5–40 V DC; requires local 100-nF ceramic bypass capacitor to suppress high-frequency switching transients. |
| 8 (Output) | Internal power switch drain | Switches between (VIN − VSAT) and ≈−0.5 V at 150 kHz; connects to catch diode anode and inductor - PCB trace area must be minimized to reduce EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 12-V output with ±4% tolerance | Eliminates need for external feedback resistors - simplifies BOM, reduces layout sensitivity, and guarantees compliance across temperature and line/load variations. |
| Bias Supply (VBS) pin | Enables powering internal circuitry from regulated 12-V output instead of VIN - increases efficiency by ~2–3% at VIN ≥24 V and light loads. |
| Integrated shutdown/soft-start | Single-pin logic-level control (≤0.6 V shutdown, >2 V active) with optional capacitor-based ramp - replaces discrete timing circuits and reduces start-up inrush by >75%. |
| Out-of-regulation error flag with delay | Provides system-level fault detection with user-adjustable hold-off time - supports reliable power-good signaling for microcontrollers and FPGAs. |
| Thermal shutdown + current limiting | Dual-stage protection (0.58–1.4-A peak current limit + 150°C junction cutoff) - ensures safe operation under short-circuit, overload, or inadequate heatsinking. |
Applications
| Industrial Power Supplies | Embedded System Point-of-Load |
|---|---|
|
Use Scenario: Converting 24-V factory bus to stable 12-V rail for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary buck regulator providing isolated, regulated 12-V output with built-in fault signaling for system diagnostics. Use Value: Delivers 0.5-A continuous current with <±4% regulation, enabling direct replacement of linear regulators while reducing heat sink size by >60%. |
Use Scenario: Generating clean 12-V supply for FPGA configuration circuitry and auxiliary logic in edge computing gateways. IC Role / Device Role / Timing Role: Step-down converter with soft-start and error flag - ensures controlled power-up and early fault detection before firmware execution. Use Value: 150-kHz switching allows use of small, low-cost inductors (<10 mm² footprint), and PDIP-8 package supports manual rework in low-volume production. |
| Telecom Line Card Power | Test & Measurement Equipment |
|
Use Scenario: Preregulating -48-V telecom supply to intermediate 12-V rail feeding downstream DC-DC converters. IC Role / Device Role / Timing Role: High-input-voltage buck preregulator with 40-V max rating - handles wide input transients common in central office environments. Use Value: Bias supply (VBS) pin connected to 12-V output improves conversion efficiency by ~2.5% at 36-V input, reducing thermal stress on board-level heatsinking. |
Use Scenario: Providing isolated 12-V supply for analog front-end amplifiers and ADC references in portable multimeters. IC Role / Device Role / Timing Role: Fixed-output switching regulator with low 85-µA standby current - extends battery life during idle periods without compromising startup speed. Use Value: Integrated error flag and delay pin enable precise power-good assertion timing, synchronizing measurement acquisition with stable supply conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2597MX-12 | Same electrical specs but in SOIC-8 surface-mount package (4.90 mm × 3.91 mm); θJA = 95°C/W vs 150°C/W for PDIP. | Better thermal performance and smaller footprint - suited for high-density PCBs where manual assembly is not required. | Select LM2597MX-12 for automated SMT production; LM2597N-12 remains optimal for through-hole prototyping and repair-friendly designs. |
| LM2596-12 | Higher 3-A output current, same 12-V fixed output, but 150-kHz frequency and different pinout - not pin-compatible; requires layout change. | Supports higher-power loads (e.g., motor drivers, multiple peripherals) but demands larger inductor and output capacitance. | Choose LM2596-12 only when >0.5-A output is needed; LM2597N-12 offers superior cost-efficiency and simplicity for sub-1-A applications. |
Compared with LM2597MX-12 and LM2596-12, the LM2597N-12 uniquely balances through-hole manufacturability, proven reliability in industrial environments, and integrated supervision features - making it ideal for legacy upgrades and low-to-moderate volume embedded power designs where ease of validation and serviceability are critical.
Availability
LM2597N-12 is available at Aetrix Electronics and suitable for industrial power supplies, embedded system point-of-load regulation, and telecom line card power requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2597N-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 experience in high-reliability power conversion solutions.
The LM2597 series belongs to TI's SIMPLE SWITCHER® portfolio - designed specifically for engineers needing easy-to-use, robust, and application-ready DC-DC converters with minimal external components and comprehensive protection features.
FAQ
What is the maximum input voltage supported by the LM2597N-12?
The LM2597N-12 supports a maximum input voltage of 40 V, with recommended operating range from 4.5 V to 40 V. This makes it suitable for 24-V and 36-V industrial bus systems, including those with transient overvoltage margins. Exceeding 40 V risks permanent damage, as absolute maximum rating is strictly enforced by internal protection circuitry.
Does the LM2597N-12 require external feedback resistors to set the 12-V output?
No, the LM2597N-12 is a fixed-output variant - its 12-V regulation is implemented internally using a precision 1.23-V reference and trimmed feedback network. Pin 4 (Feedback) is unused and must be left open or grounded per datasheet guidance; no external resistors are needed or permitted.
Can the LM2597N-12 be used in a negative-output (inverting) configuration?
Yes, the LM2597N-12 can be configured as a positive-to-negative converter by bootstrapping the ground pin to the negative output rail. The datasheet provides a validated inverting −12-V circuit (Figure 24 variant), though maximum output current depends on VIN and |VOUT| - e.g., 24-V input yields ~0.3-A at −12 V due to power dissipation limits.
How does the Bias Supply (VBS) pin improve efficiency in the LM2597N-12?
When the VBS pin is connected to the 12-V output, internal circuitry draws power from VOUT instead of VIN - reducing power loss in the internal LDO and lowering junction temperature. At 25-V input and light load, this improves efficiency by ~2.5%, as confirmed in Figure 20 of the LM2597 datasheet (SNVS119D).
Is the LM2597N-12 RoHS compliant and lead-free?
Yes, the LM2597N-12 is RoHS compliant and lead-free per TI's packaging standards. It uses matte tin lead finish on PDIP leads and meets JEDEC J-STD-020 moisture sensitivity level (MSL) requirements. Full compliance documentation is available in TI's official product change notices and material declarations.
LM2597N-12 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 12V
- Voltage - Output (Max):
- -
- 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
LM2597N-12 FAQ
1.How can I place an order for LM2597N-12 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2597N-12 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 LM2597N-12 reliable?
The price and inventory of LM2597N-12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2597N-12 is usually 5 days.
3.What payment methods are accepted for LM2597N-12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2597N-12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2597N-12?
LM2597N-12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2597N-12 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 LM2597N-12?
For technical support, including LM2597N-12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2597N-12 requirements.
6.How does Aetrix verify that LM2597N-12 is sourced from the original manufacturer or authorized distributors?
All LM2597N-12 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 LM2597N-12 meets industry standards.
7.What is the process for return or replacement of LM2597N-12?
All LM2597N-12 units undergo pre-shipment inspection (PSI). If there is an issue with LM2597N-12, 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 LM2597N-12 part is unused and in its original packaging.
Return procedure for LM2597N-12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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