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Texas Instruments LM2597MX-3.3
- Part No.:
- LM2597MX-3.3
- Manufacturer:
- Texas Instruments
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM2597MX-3.3.pdf
- Description:
- IC REG BUCK 3.3V 500MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,080
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Product details
Overview
LM2597MX-3.3 from Texas Instruments is a monolithic 150-kHz nonsynchronous step-down (buck) DC-DC converter IC delivering up to 0.5 A output current with fixed 3.3-V output, ±4% output voltage tolerance over line and load, input voltage range up to 40 V (LM2597), and integrated shutdown/soft-start and error flag functions - used in industrial power supplies, embedded system point-of-load regulation, and automotive auxiliary rails.
For engineers reviewing the LM2597MX-3.3 datasheet, LM2597MX-3.3 pinout, LM2597MX-3.3 application, or LM2597MX-3.3 equivalent, key selection criteria include its 3.3-V fixed output accuracy, 85-μA standby quiescent current, SOIC-8 package compatibility, bias supply (VBS) pin for efficiency optimization at high VIN/low VOUT, and thermal shutdown protection.
Technical Context
The LM2597MX-3.3 implements a fixed-frequency (150 kHz) current-mode buck topology with internal oscillator, PWM comparator, and N-channel MOSFET switch. It uses external diode, inductor, and capacitors to form a complete switching regulator, requiring no external compensation due to built-in frequency compensation.
Its control architecture includes an error amplifier comparing feedback voltage against 1.23-V internal reference, a current-sense circuit enabling two-stage current limiting (0.65–1.3 A peak), and a dedicated bias supply (VBS) pin that powers internal circuitry from VOUT instead of VIN - improving efficiency by reducing power dissipation in high-input-voltage, low-output-current conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±4% over full line/load/temperature range - ensures stable logic rail compliance for 3.3-V microcontrollers and FPGAs. |
| Max Output Current | 0.5 A DC - supports moderate-power digital subsystems without external current boosting. |
| Input Voltage Range | 4.5 V to 40 V - accommodates wide-input industrial and automotive battery-supplied systems (e.g., 12-V nominal with transients). |
| Switching Frequency | 150 kHz (±15%) - enables use of compact, low-cost standard inductors and reduces EMI compared to lower-frequency alternatives. |
| Standby Quiescent Current | 85 μA typical - minimizes battery drain in always-on or low-power sleep modes. |
| Efficiency | 80% typical at VIN = 12 V, IOUT = 0.5 A - reduces thermal load on PCB copper traces, eliminating need for heatsinks in most applications. |
| Oscillator Accuracy | ±15% over temperature - sufficient for non-critical timing; allows predictable filter design with margin-based component selection. |
Pinout & Package
LM2597MX-3.3 is packaged in an 8-pin SOIC (D package), body size 4.90 mm × 3.91 mm, surface-mount compatible with standard reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - Error Flag | Open-collector output | Asserts low when VOUT drops >5% below 3.3 V; delays release until output stabilizes - usable as microprocessor reset signal. |
| 2 - Delay | Capacitor-connected timing node | Sets delay between VOUT reaching 95% and Error Flag deassertion - prevents premature system wake-up during soft-start. |
| 3 - Bias Supply (VBS) | Power input for internal circuitry | Accepts VOUT (≥3.5 V) to reduce VIN current draw and improve efficiency - not usable with 3.3-V output unless externally boosted. |
| 4 - Feedback | Inverting input of error amplifier | Connected to resistor divider from VOUT; senses regulated voltage referenced to 1.23-V internal reference - unused in fixed 3.3-V version. |
| 5 - Shutdown/Soft-Start | Dual-function digital control input | Pulled low for shutdown (IQ ≈ 85 μA); capacitor added for controlled VOUT ramp - limits inrush current and avoids input rail sag. |
| 6 - Ground | Power and signal reference | Common return path for internal switch, error amp, and bias circuitry - requires low-impedance PCB plane connection. |
| 7 - +VIN | Main power input | Accepts 4.5–40 V DC; requires local ceramic bypass capacitor (≥100 nF) to suppress switching noise and supply peak currents. |
| 8 - Output | Internal N-MOSFET drain | Switches between VIN−VSAT (~0.9–1.2 V drop) and ~−0.5 V; connects to external catch diode and inductor - minimal copper area required to limit EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Soft-Start | Capacitor-programmable output voltage ramp - eliminates inrush current spikes and prevents input supply collapse during startup. |
| Out-of-Regulation Error Flag | Open-drain output with built-in delay - provides reliable power-good signaling for sequenced system boot without external comparators. |
| Bias Supply (VBS) Pin | Enables internal circuitry to be powered from VOUT instead of VIN - improves efficiency by up to 5% at high VIN/low IOUT operating points. |
| Thermal Shutdown & Current Limit | Two-stage current limiting (0.65–1.3 A) plus junction-temperature cutoff at 150°C - protects device under short-circuit or overload without external sensing. |
| Fixed-Frequency Operation | 150-kHz internal oscillator - simplifies EMI filtering design and enables consistent inductor sizing across designs. |
Applications
| Industrial Power Supply | Embedded System PoL |
|---|---|
Use Scenario: Converting 24-V factory bus to clean 3.3-V rail for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary step-down regulator providing isolated, regulated 3.3-V supply with error flag monitoring for system health reporting. Use Value: ±4% output tolerance and 80% efficiency ensure stable MCU operation while minimizing heat buildup on dense industrial PCBs. |
Use Scenario: Generating 3.3-V core voltage for ARM Cortex-M4 microcontrollers in portable test equipment. IC Role / Device Role / Timing Role: Standalone buck converter with soft-start and shutdown control, synchronized to host processor power sequencing. Use Value: 85-μA standby current extends battery life; SOIC-8 footprint enables compact layout alongside MCU and flash memory. |
| Automotive Auxiliary Rail | Positive-to-Negative Converter |
Use Scenario: Deriving 3.3-V logic supply from 12-V vehicle battery with transient tolerance up to 40 V. IC Role / Device Role / Timing Role: Input-transient-hardened buck regulator with thermal shutdown - operates across −40°C to +125°C ambient. Use Value: Wide 4.5–40 V input range and 150°C junction rating meet automotive cold-crank and load-dump requirements without derating. |
Use Scenario: Generating −3.3-V analog supply from +12-V source for op-amp biasing in data acquisition front-ends. IC Role / Device Role / Timing Role: Inverting buck-boost configuration using LM2597MX-3.3's internal switch and external diode/inductor. Use Value: Fixed 3.3-V reference enables precise negative rail generation; error flag signals inversion failure during startup or fault. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596-3.3 | Lower max input voltage (40 V same), but 1.5-A output current and 150-kHz frequency - higher current capability with identical pinout and control features. | Supports higher-power loads (e.g., multi-rail FPGA boards) where 0.5-A is insufficient; requires larger inductor and diode. | Select LM2596-3.3 when >0.5-A output current is needed; verify thermal performance with increased power dissipation. |
| TPS54302DDCR | 3-A synchronous buck with 2.5–6.0-V input, 3.3-V fixed output, 2-MHz switching, and integrated high-side/low-side MOSFETs - no external diode required. | Targets space-constrained, high-efficiency applications (e.g., telecom modules); incompatible pinout and much narrower input range. | Choose TPS54302DDCR for compact, high-efficiency designs with low VIN; LM2597MX-3.3 remains preferred for wide-input, cost-sensitive industrial use. |
Compared with LM2596-3.3 and TPS54302DDCR, the LM2597MX-3.3 offers optimal balance of wide-input capability (4.5–40 V), proven reliability in harsh environments, and minimal BOM count - making it ideal for legacy-compatible, thermally constrained, and cost-driven buck regulator implementations.
Availability
LM2597MX-3.3 is available at Aetrix Electronics and suitable for industrial power supplies, embedded system point-of-load regulation, and automotive auxiliary rails requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2597MX-3.3 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 communications infrastructure applications.
FAQ
What is the maximum input voltage rating for LM2597MX-3.3?
The LM2597MX-3.3 has a maximum input voltage rating of 40 V, as specified in the Absolute Maximum Ratings table. This applies to the standard LM2597 variant (not the HV version). Exceeding 40 V risks permanent damage, even briefly. For applications requiring up to 60 V input, the LM2597HV-3.3 must be selected instead.
Can the LM2597MX-3.3 be used in an inverting configuration to generate −3.3 V?
Yes, the LM2597MX-3.3 can be configured as a positive-to-negative inverting regulator using the topology shown in TI's Figure 24. It leverages the internal switch and external diode/inductor to produce −3.3 V from a positive input. Note that the maximum |VIN| + |VOUT| must not exceed 40 V, and startup inrush current is higher than in buck mode - soft-start is strongly recommended.
Does the LM2597MX-3.3 require an external feedback resistor network?
No, the LM2597MX-3.3 is a fixed-output version with internal feedback divider set for 3.3 V. Pin 4 (Feedback) is internally connected and must be left unconnected in standard operation. External resistors are only required for the adjustable version (LM2597ADJ); adding them to LM2597MX-3.3 will disrupt regulation.
What is the purpose of the Bias Supply (VBS) pin on the LM2597MX-3.3?
The VBS pin allows internal circuitry to be powered from the regulated output (VOUT) rather than VIN, improving efficiency - especially at high input voltages and light loads. However, because VBS requires ≥3.5 V to operate and LM2597MX-3.3 outputs only 3.3 V, this feature cannot be used directly with this part without external boosting.
How does the Error Flag output function on the LM2597MX-3.3?
The Error Flag (Pin 1) is an open-collector output that pulls low when VOUT falls more than 5% below 3.3 V. At startup, it remains low until VOUT reaches 95% of nominal and the Delay pin capacitor times out - providing a delayed, glitch-free power-good signal usable for microcontroller reset assertion.
LM2597MX-3.3 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:
- 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):
- 3.3V
- Voltage - Output (Max):
- -
- 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-3.3 FAQ
1.How can I place an order for LM2597MX-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2597MX-3.3 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-3.3 reliable?
The price and inventory of LM2597MX-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2597MX-3.3 is usually 5 days.
3.What payment methods are accepted for LM2597MX-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2597MX-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2597MX-3.3?
LM2597MX-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2597MX-3.3 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-3.3?
For technical support, including LM2597MX-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2597MX-3.3 requirements.
6.How does Aetrix verify that LM2597MX-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2597MX-3.3 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-3.3 meets industry standards.
7.What is the process for return or replacement of LM2597MX-3.3?
All LM2597MX-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2597MX-3.3, 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-3.3 part is unused and in its original packaging.
Return procedure for LM2597MX-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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