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Texas Instruments LM2940CSX-15
- Part No.:
- LM2940CSX-15
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-4, D2PAK (3 Leads + Tab), TO-263AA
- Datasheet:
-
LM2940CSX-15.pdf
- Description:
- IC REG LIN 15V 1A DDPAK/TO263-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,744
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Product details
Overview
LM2940CSX-15 from Texas Instruments is a 15 V, 1 A low-dropout linear voltage regulator in DDPAK/TO-263 (KTT) package, featuring 0.5 V typical dropout at full load, reverse battery protection, and internal short-circuit/thermal shutdown. It delivers stable output for automotive power rails, industrial control modules, and battery-powered systems requiring robust input transient immunity.
For engineers reviewing the LM2940CSX-15 datasheet, LM2940CSX-15 pinout, LM2940CSX-15 application, or LM2940CSX-15 equivalent, key selection criteria include dropout voltage at 1 A, reverse polarity tolerance (−30 V DC), thermal performance with PCB copper heatsinking, and mandatory 22 μF minimum output capacitance with ESR constraints.
Technical Context
The LM2940CSX-15 uses a PNP pass transistor architecture enabling low dropout operation while maintaining stability without external compensation. Its quiescent current reduction circuit lowers ground current to 30 mA at 5 V VIN–VOUT differential, improving efficiency during light-load conditions.
Designed for vehicular environments, it integrates mirror-image insertion protection, automatic shutdown during load-dump transients (>26 V), and −30 V reverse-battery survival. Output voltage is trimmed before assembly to ±2% initial accuracy over temperature (0°C to 125°C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 15.0 V nominal, trimmed to 14.55–15.45 V over full temperature range - ensures stable logic supply for microcontrollers and sensors. |
| Dropout Voltage | 0.5 V typical @ 1 A load - enables regulation from 15.5 V input, critical for 12 V automotive systems with ripple and sag. |
| Max Input Voltage | 26 V continuous - supports 24 V nominal industrial buses and withstands ISO 7637-2 pulse 5a (load dump). |
| Reverse Polarity | −30 V DC survivable - protects against accidental battery reversal in vehicle service scenarios. |
| Quiescent Current | 30 mA @ 1 A load and 5 V VIN–VOUT - minimizes standby power loss in always-on modules. |
| Output Capacitance | ≥22 μF required with controlled ESR - mandates use of tantalum or hybrid aluminum/tantalum capacitors for stability. |
| Thermal Resistance θJA | 80°C/W (DDPAK/TO-263, no heatsink) - requires ≥1 in² copper pour and thermal vias for >1 W dissipation at 85°C ambient. |
Pinout & Package
LM2940CSX-15 is housed in a 3-pin DDPAK/TO-263 (KTT) thermally enhanced surface-mount package with exposed thermal pad fused to pin 2 and pin 7 (GND). Pin 5 and pin 6 must be tied together on PCB per TI design guidance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (INPUT) | Unregulated input supply connection | Accepts 15.5–26 V; must include ≥100 μF bulk capacitor near device to suppress transients. |
| Pin 2 & 7 (GND) | Power ground reference and thermal pad | Electrically and thermally connected to exposed DAP; requires soldered thermal via array to inner ground plane. |
| Pin 3 (OUTPUT) | Regulated 15 V output | Delivers up to 1 A; requires ≥22 μF output capacitor with ESR 0.1–1 Ω (per load current) for loop stability. |
Key Features
| Feature | Design Value |
|---|---|
| Reverse battery protection | Withstands −30 V DC input without damage - eliminates need for external series diode in automotive harnesses. |
| Load-dump shutdown | Auto-shutdown during >26 V transients (e.g., ISO 7637-2 Pulse 5a) - prevents overvoltage stress on downstream ICs. |
| Mirror-image insertion immunity | No damage if installed backward - simplifies automated assembly and field replacement in high-volume automotive ECUs. |
| Thermal shutdown + current limit | Internal foldback current limiting and 150°C junction shutdown - enables safe operation under sustained overload or poor heatsinking. |
| Low-noise output | 450 μVrms noise (10 Hz–100 kHz) - suitable for analog sensor front-ends and precision ADC references without added filtering. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC I/O Power Supply |
|---|---|
Use Scenario: Regulating 15 V rail for microcontroller, CAN transceiver, and analog sensor interfaces in under-hood BCM units. IC Role / Device Role / Timing Role: Primary 15 V LDO supplying core logic and communication peripherals with transient immunity. Use Value: Survives −30 V reverse battery and 75 V load-dump pulses without external protection, reducing BOM count by two diodes and one TVS. |
Use Scenario: Providing isolated 15 V bias for analog input conditioning circuits in modular PLC backplanes. IC Role / Device Role / Timing Role: Stable, low-noise local regulator decoupling sensitive op-amps and 16-bit ADCs from noisy 24 V system bus. Use Value: 450 μVrms output noise and 66 dB ripple rejection at 120 Hz enable <1 LSB error in 16-bit measurements without additional LC filtering. |
| Off-Grid Solar Charge Controller | Commercial HVAC Control Panel |
Use Scenario: Generating 15 V for MCU and display driver in solar charge controllers exposed to wide-input battery banks (12–28 V). IC Role / Device Role / Timing Role: Main system regulator handling variable input from lead-acid/LiFePO₄ batteries with deep discharge recovery. Use Value: 0.5 V dropout allows regulation down to 15.5 V input - extends usable battery range by ~0.8 V compared to standard 2 V dropout regulators. |
Use Scenario: Powering 15 V fan controllers, relay drivers, and touch-screen interface in HVAC panels operating in unconditioned mechanical rooms. IC Role / Device Role / Timing Role: Robust local regulator tolerant of 85°C ambient and 100 ms line transients from compressor switching. Use Value: Guaranteed operation from 0°C to 125°C junction temperature and 75 V transient suppression eliminate derating concerns in high-temp enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2940CT-15/NOPB | TO-220 (NDE) through-hole package; same electrical specs but higher θJA (60°C/W) and no thermal pad fusion. | Preferred for prototyping, manual repair, or legacy through-hole designs where thermal vias are impractical. | Select when board reworkability or heatsink mounting is prioritized over PCB area and thermal performance. |
| TPS7A4700RGWR | Ultra-low-noise (4.7 μVrms) 1 A LDO with 20 V max input; no reverse-battery or load-dump protection. | Suitable for ultra-sensitive analog signal chains (e.g., audio, precision instrumentation) but requires external protection for automotive use. | Choose only for noise-critical non-automotive applications; not drop-in due to missing fault protections and different pinout. |
Compared with LM2940CT-15/NOPB, LM2940CSX-15 offers superior thermal performance via PCB copper heatsinking but requires SMT assembly expertise; versus TPS7A4700RGWR, it trades ultra-low noise for integrated automotive-grade fault resilience - making it the sole choice for cost-sensitive, ruggedized 15 V power rails.
Availability
LM2940CSX-15 is available at Aetrix Electronics and suitable for automotive electronics, industrial control systems, and off-grid energy management requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM2940CSX-15 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 and embedded processing technologies, with decades of automotive-grade reliability validation and broad power management portfolio coverage.
The LM2940 family was engineered specifically for harsh-environment 12 V/24 V vehicular systems, delivering integrated reverse-polarity, load-dump, and mirror-insertion protection without external components - targeting body electronics, engine control, and ADAS subsystems.
FAQ
What is the maximum input voltage rating for LM2940CSX-15?
The LM2940CSX-15 has an absolute maximum input voltage of 26 V for continuous operation. During transient events such as load dump, it automatically shuts down to protect itself and downstream circuitry - surviving pulses up to 75 V for ≤100 ms per ISO 7637-2 specifications. Exceeding 26 V continuously risks permanent damage.
Does LM2940CSX-15 require an input capacitor?
Yes, LM2940CSX-15 requires a minimum 100 μF low-ESR aluminum or tantalum input capacitor placed within 10 mm of the INPUT pin. This stabilizes the input during load transients and prevents oscillation caused by source impedance - especially critical when powered from long cables or battery leads with inductance.
Can LM2940CSX-15 be used without a heatsink?
LM2940CSX-15 can operate without an external heatsink only if power dissipation remains below ~1.5 W at 85°C ambient - achievable with ≤1 V input-output differential at 1 A. For higher differentials, a ≥1 in² copper pour with ≥6 thermal vias under the exposed pad is mandatory to maintain θJA ≤80°C/W and prevent thermal shutdown.
What output capacitor types are compatible with LM2940CSX-15?
LM2940CSX-15 requires ≥22 μF output capacitance with ESR between 0.1 Ω and 1 Ω (depending on load current). Solid tantalum or polymer aluminum capacitors meet this best; standard electrolytics often exceed ESR limits at low temperature. Parallel configurations (e.g., 15 μF Al + 10 μF Ta) are recommended for wide-temperature stability.
Is LM2940CSX-15 pin-compatible with other LM2940 variants?
LM2940CSX-15 shares identical pinout (INPUT-GND-OUTPUT) and package (KTT) with all LM2940CSX-x variants (e.g., LM2940CSX-12, LM2940CSX-5.0), enabling direct substitution in layout when output voltage and thermal requirements align. However, output voltage trim is factory-set per variant - no external adjustment is possible.
LM2940CSX-15 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-263-4, D2PAK (3 Leads + Tab), TO-263AA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 26V
- Voltage - Output (Min/Fixed):
- 15V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.8V @ 1A
- Current - Output:
- 1A
- Current - Quiescent (Iq):
- 10 mA
- Current - Supply (Max):
- 15 mA
- PSRR:
- 66dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature, Reverse Polarity, Short Circuit
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-3)
LM2940CSX-15 FAQ
1.How can I place an order for LM2940CSX-15 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2940CSX-15 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 LM2940CSX-15 reliable?
The price and inventory of LM2940CSX-15 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2940CSX-15 is usually 5 days.
3.What payment methods are accepted for LM2940CSX-15?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2940CSX-15 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2940CSX-15?
LM2940CSX-15 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2940CSX-15 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 LM2940CSX-15?
For technical support, including LM2940CSX-15 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2940CSX-15 requirements.
6.How does Aetrix verify that LM2940CSX-15 is sourced from the original manufacturer or authorized distributors?
All LM2940CSX-15 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 LM2940CSX-15 meets industry standards.
7.What is the process for return or replacement of LM2940CSX-15?
All LM2940CSX-15 units undergo pre-shipment inspection (PSI). If there is an issue with LM2940CSX-15, 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 LM2940CSX-15 part is unused and in its original packaging.
Return procedure for LM2940CSX-15:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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