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Texas Instruments LM2597MX-ADJ/NOPB
- Part No.:
- LM2597MX-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM2597MX-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 500MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,192
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Product details
Overview
LM2597MX-ADJ/NOPB from Texas Instruments is a monolithic nonsynchronous step-down (buck) DC-DC switching regulator IC delivering up to 0.5 A output current with adjustable output voltage from 1.2 V to 37 V, fixed 150-kHz switching frequency, and input voltage range up to 40 V. It integrates internal frequency compensation, soft-start, shutdown control, error flag, and bias supply (VBS) functionality for high-efficiency power conversion in space-constrained industrial and embedded systems.
For engineers reviewing the LM2597MX-ADJ/NOPB datasheet, LM2597MX-ADJ/NOPB pinout, LM2597MX-ADJ/NOPB application, or LM2597MX-ADJ/NOPB equivalent, key selection criteria include its ±4% output voltage tolerance over line/load/temperature, 85 μA standby quiescent current, 1.23 V feedback reference, 0.9–1.2 V switch saturation voltage, and SOIC-8 package compatibility with standard buck layout practices.
Technical Context
The LM2597MX-ADJ/NOPB implements a current-mode controlled buck topology with an integrated 0.5-A NPN power switch and fixed 150-kHz oscillator. Its feedback loop uses a precision 1.23 V reference at the FB pin to regulate output via external resistor divider, enabling programmable output from 1.2 V to 37 V. The VBS pin allows internal circuitry to be powered from the regulated output instead of VIN-improving efficiency at high input/low output conditions.
It features dual-function SD/SS pin supporting logic-level shutdown (85 μA IQ) and capacitor-based soft-start, plus open-collector Error_Flag with delay timing controlled by external capacitor on the DELAY pin. Protection includes thermal shutdown, two-stage current limiting (0.65–1.3 A peak), and undervoltage lockout behavior derived from internal biasing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 0.5 A DC maximum-supports mid-power point-of-load conversion without external current boosting. |
| Input Voltage Range | 4.5 V to 40 V-enables direct regulation from 12 V, 24 V, or 36 V industrial rails. |
| Output Voltage Range | 1.2 V to 37 V (adjustable)-set precisely using external R1/R2 divider; 1.23 V FB reference ensures ±4% total tolerance. |
| Switching Frequency | 150 kHz (±15%)-enables use of low-cost, off-the-shelf 100–150 μH inductors and reduces EMI filtering complexity. |
| Quiescent Current | 5–10 mA operating / 85 μA standby-minimizes no-load power loss in battery-backed or always-on systems. |
| Efficiency | Up to 88% (e.g., 12 VIN → 12 VOUT, 0.5 A)-enhanced by VBS pin connection to output under light-load/high-VIN conditions. |
| Saturation Voltage | 0.9–1.2 V at 0.5 A-defines conduction loss in internal NPN switch; impacts minimum dropout and thermal design. |
Pinout & Package
LM2597MX-ADJ/NOPB is housed in an 8-pin SOIC (D) package measuring 4.90 mm × 3.91 mm, optimized for surface-mount assembly and thermal performance (RθJA = 95°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Error_Flag) | Open-collector fault indicator | Asserts low when VOUT drops >5%; used for microprocessor reset or system monitoring with external pull-up. |
| 2 (Delay) | Capacitor-timed flag delay | Controls time between VOUT reaching 95% and Error_Flag going high-prevents false resets during startup. |
| 3 (Bias_Supply) | Internal bias rail input | Accepts 3.5–30 V to power internal circuitry from VOUT, reducing VIN current and improving efficiency at high input voltages. |
| 4 (Feedback) | Voltage sense input | References 1.23 V internal bandgap; sets output via R1/R2 divider-determines regulation accuracy and stability. |
| 5 (Shutdown/Soft-Start) | Logic control & ramp timing | Pull low for shutdown (85 μA IQ); add capacitor for controlled VOUT ramp-limits inrush and eases input source stress. |
| 6 (Ground) | Power and signal reference | Common return for internal switch, control circuitry, and external components-requires low-impedance PCB plane. |
| 7 (+VIN) | Main power input | Accepts 4.5–40 V; requires local ceramic bypass capacitor to handle high di/dt switching currents. |
| 8 (Output) | Switch node | Drives external catch diode and inductor; swings between ~−0.5 V and (VIN − VSAT)-must minimize copper area to reduce EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Output (1.2–37 V) | Enables single BOM to support multiple output rails via resistor selection-reduces inventory and simplifies design reuse. |
| Bias Supply (VBS) Pin | Reduces input current draw and junction temperature when connected to regulated output-critical for high-VIN/low-VOUT operation. |
| Integrated Soft-Start | Eliminates need for external timing circuitry; controls output ramp rate and limits peak inrush current to ~160 mA (vs. 700 mA without). |
| Error Flag with Delay | Provides reliable power-good signaling with user-defined hold-off time-enables clean system reset sequencing without additional comparators. |
| Thermal + Current Protection | Two-stage current limit and thermal shutdown prevent damage during overload, short-circuit, or poor heatsinking-ensures robust field operation. |
Applications
| Industrial PLC I/O Module | Automotive Body Control Unit |
|---|---|
Use Scenario: Powering isolated 3.3 V or 5 V logic rails from a 24 V vehicle battery or 36 V industrial bus with transient immunity. IC Role / Device Role / Timing Role: Primary buck regulator providing stable, efficient local DC-DC conversion with built-in fault signaling. Use Value: 40 V max input withstands load-dump transients; 85 μA standby current extends battery life in sleep modes. | Use Scenario: Generating 5 V for microcontroller, CAN transceiver, and sensor interfaces in automotive body electronics. IC Role / Device Role / Timing Role: Nonsynchronous buck controller managing power sequencing and reset signaling via Error_Flag. Use Value: Adjustable version supports flexible rail generation; soft-start prevents brownout during cold-crank conditions. |
| Point-of-Load Telecom Supply | Portable Test Equipment |
Use Scenario: Stepping down 48 V telecom backplane to 12 V intermediate bus for downstream converters. IC Role / Device Role / Timing Role: Preregulator improving overall system efficiency and reducing thermal load on linear post-regulators. Use Value: 150 kHz switching enables compact magnetics; VBS pin improves efficiency at 48 VIN/12 VOUT operation. | Use Scenario: Battery-powered handheld instrument requiring low-noise, low-quiescent 3.3 V rail with power-good indication. IC Role / Device Role / Timing Role: Main DC-DC converter with integrated reset generator for FPGA or MCU initialization. Use Value: Error_Flag + Delay pin provides precise, capacitor-adjustable power-on reset timing independent of microcontroller. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596-ADJ | Same 150-kHz frequency and 0.5-A rating, but lower 40 V max input (no HV variant); slightly higher 1.25 V FB reference. | Lacks Bias_Supply (VBS) pin and Error_Flag delay timing-requires external reset IC for sequenced startup. | Choose when cost sensitivity outweighs efficiency optimization and fault signaling needs. |
| TPS54302DDAR | Higher 3-A rating, 2.5-MHz switching, integrated MOSFETs, and 3-V min input-but narrower 6-V max input range. | Requires different layout and compensation; lacks dedicated error flag and delay pins-relies on PG pin with fixed timing. | Prefer for higher-current, smaller-footprint designs where 6-V input ceiling is acceptable. |
Compared with LM2596-ADJ, LM2597MX-ADJ/NOPB offers superior fault signaling and efficiency tuning via VBS; versus TPS54302DDAR, it trades higher current and frequency for wider input range, simpler external component count, and dedicated power-good timing control.
Availability
LM2597MX-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, and portable test equipment requiring stable component supply, long-term lifecycle assurance, and consistent parametric performance across production batches.
Supply support for LM2597MX-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 leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in high-reliability power conversion ICs.
The LM2597 series belongs to TI's SIMPLE SWITCHER® portfolio-designed specifically for ease-of-use, minimal external component count, and robust operation in industrial, automotive, and telecom power applications.
FAQ
What is the minimum input voltage required for LM2597MX-ADJ/NOPB to regulate a 3.3 V output?
The LM2597MX-ADJ/NOPB requires a minimum input voltage of 4.5 V per its Recommended Operating Conditions. This headroom ensures stable regulation at 3.3 V output while accommodating switch saturation voltage (~0.9 V) and feedback loop margin. Operation below 4.5 V may result in dropout or unregulated output.
Can LM2597MX-ADJ/NOPB be used in an inverting (positive-to-negative) configuration?
Yes, LM2597MX-ADJ/NOPB supports inverting regulator topologies per TI's Figure 24. By bootstrapping the GND pin to the negative output and grounding the FB pin, it regulates inverted outputs such as –5 V or –12 V. Maximum |VIN| + |VOUT| must not exceed 40 V, and a Schottky catch diode is recommended.
How does the Bias_Supply (VBS) pin improve efficiency in LM2597MX-ADJ/NOPB?
The VBS pin powers internal circuitry from the regulated output instead of VIN, reducing input current draw-especially beneficial at high input voltages (e.g., 36 V) and low output voltages (e.g., 3.3 V or 5 V). Efficiency gains of 2–5% are typical, as shown in Figures 19–20 of the LM2597 datasheet.
What is the purpose of the Delay pin on LM2597MX-ADJ/NOPB?
On LM2597MX-ADJ/NOPB, the Delay pin sets the time interval between when VOUT reaches 95% of target and when the Error_Flag output transitions high. An external capacitor determines this delay-enabling precise power-good timing for microprocessor reset without external timers or comparators.
Does LM2597MX-ADJ/NOPB require an external catch diode, and what type is recommended?
Yes, LM2597MX-ADJ/NOPB requires an external catch diode due to its nonsynchronous buck architecture. A Schottky diode (e.g., 1N5822) is recommended for VOUT ≤ 12 V to minimize forward voltage drop and conduction loss; for higher outputs or cost-sensitive designs, a fast-recovery PN diode like 1N4007 may be used with reduced efficiency.
LM2597MX-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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):
- 1.2V
- 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
LM2597MX-ADJ/NOPB FAQ
1.How can I place an order for LM2597MX-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2597MX-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 LM2597MX-ADJ/NOPB reliable?
The price and inventory of LM2597MX-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 LM2597MX-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2597MX-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2597MX-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2597MX-ADJ/NOPB?
LM2597MX-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2597MX-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 LM2597MX-ADJ/NOPB?
For technical support, including LM2597MX-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2597MX-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2597MX-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2597MX-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 LM2597MX-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2597MX-ADJ/NOPB?
All LM2597MX-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2597MX-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 LM2597MX-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2597MX-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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