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Texas Instruments LM2940IMPX-9.0
- Part No.:
- LM2940IMPX-9.0
- Manufacturer:
- Texas Instruments
- Package:
- TO-261-4, TO-261AA
- Datasheet:
-
LM2940IMPX-9.0.pdf
- Description:
- IC REG LINEAR 9V 1A SOT223-4
- Quantity:
- Payment:
- Shipping:
Inventory:4,780
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Product details
Overview
LM2940IMPX-9.0 from Texas Instruments is a 1A low-dropout linear voltage regulator delivering a fixed 9.0V output with typical dropout voltage of 0.5V at 1A load, reverse battery protection, and internal short-circuit/thermal overload protection. It operates over −40°C to +85°C ambient temperature and is designed for automotive and industrial power rails where input transients and polarity reversal are common.
For engineers reviewing the LM2940IMPX-9.0 datasheet, LM2940IMPX-9.0 pinout, LM2940IMPX-9.0 application, or LM2940IMPX-9.0 equivalent, key selection criteria include dropout performance under 1A load, ESR-sensitive stability requirements (≥22 μF output capacitor), thermal derating in SOT-223 packaging, and reverse-polarity survivability up to −30V DC.
Technical Context
The LM2940IMPX-9.0 uses a PNP pass transistor architecture enabling low dropout while maintaining stable regulation without external compensation. Its quiescent current reduction circuit lowers ground current to 30 mA at 5V VIN–VOUT differential and 1A load - critical for battery-powered systems.
It integrates mirror-image insertion protection, automatic shutdown during load-dump transients (>26V), and reverse-battery tolerance down to −30V DC. The device requires ≥22 μF output capacitance with controlled ESR (typically 0.1–1 Ω) to ensure loop stability across temperature and load conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 9.0 V ±2.7% (min/max over temp and load), trimmed before assembly for accuracy without external feedback. |
| Dropout Voltage | 0.5 V typical at 1 A load; enables regulation with only 9.5 V input - essential for 12 V automotive systems during cranking. |
| Output Current | Guaranteed ≥1 A continuous; short-circuit current ≥1.9 A ensures robust fault handling without latch-up. |
| Quiescent Current | 30 mA max at 1 A load and 5 V VIN–VOUT differential; drops significantly above 3 V differential to extend battery life. |
| Reverse Polarity Protection | Withstands −30 V DC input continuously; survives −75 V transient pulses ≤100 ms - eliminates need for external diode. |
| Operating Temperature | −40°C to +85°C ambient (SOT-223 package); junction limited to 125°C with thermal shutdown activation. |
| Output Capacitor Requirement | Minimum 22 μF low-ESR capacitor required; ESR must be 0.1–1 Ω across operating temperature to prevent oscillation. |
Pinout & Package
SOT-223 (DCY) 4-lead plastic package with exposed thermal pad (pin 2). Pin 1 = Input, Pin 2 = Ground (tab), Pin 3 = Output, Pin 4 = Ground. Thermal pad must be soldered to PCB copper plane for thermal performance (θJA = 174°C/W unmounted, ~74°C/W with 1-in² 1-oz copper).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (INPUT) | Regulator input supply connection | Accepts 10.5 V to 26 V DC; withstands −30 V reverse bias and −75 V transients. |
| Pin 2 (GND / Tab) | Power ground and thermal interface | Exposed copper tab is electrically GND and primary heat path; must be soldered to ≥1-in² PCB copper area. |
| Pin 3 (OUTPUT) | Stable 9.0 V regulated output | Delivers up to 1 A; requires ≥22 μF output capacitor with controlled ESR for stability. |
| Pin 4 (GND) | Signal ground reference | Provides low-impedance return path for internal circuitry; ties to same ground net as Pin 2. |
Key Features
| Feature | Design Value |
|---|---|
| Low Dropout Operation | 0.5 V typical dropout at 1 A enables use in 12 V automotive systems even during cold-crank (≤6.5 V battery). |
| Integrated Reverse Battery Protection | No external components needed to survive −30 V DC reverse connection - reduces BOM and layout complexity. |
| Transient Shutdown Protection | Automatically disables output during >26 V line transients (e.g., load dump), protecting downstream circuitry. |
| Quiescent Current Reduction | Ground current drops to <15 mA when VIN–VOUT >3 V - extends battery runtime in always-on applications. |
| Mirror-Image Insertion Tolerance | Unharmed by accidental upside-down mounting - improves manufacturing yield and field reliability. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC I/O Power Rail |
|---|---|
|
Use Scenario: Powers microcontroller, CAN transceiver, and sensor interface circuits in vehicle door modules. IC Role / Device Role / Timing Role: Primary 9 V local regulator supplying noise-sensitive logic from noisy 12 V battery bus. Use Value: Reverse-battery and load-dump immunity eliminate need for external protection diodes or TVS, reducing board space by 30%. |
Use Scenario: Provides clean 9 V rail for analog input conditioning and isolated digital I/O in factory automation controllers. IC Role / Device Role / Timing Role: Point-of-load regulator converting 24 V DC industrial supply to stable 9 V for precision ADC references. Use Value: 0.5 V dropout allows operation down to 9.5 V input - maintains regulation during brownout events on shared 24 V bus. |
| Telematics GPS/GSM Module | Off-Grid Solar Charge Controller |
|
Use Scenario: Supplies 9 V to GPS receiver and cellular modem in vehicle tracking units powered by lead-acid battery. IC Role / Device Role / Timing Role: Low-quiescent LDO maintaining system wake-up capability during extended sleep cycles. Use Value: 30 mA IQ at full load and sub-15 mA in high-differential mode extends battery life by >40% vs. legacy regulators. |
Use Scenario: Regulates 12–28 V solar panel output to fixed 9 V for battery management IC and status LED drivers. IC Role / Device Role / Timing Role: Input-tolerant front-end regulator handling wide PV voltage swings and polarity reversals during shading. Use Value: −30 V reverse DC rating and −75 V transient tolerance enable direct connection to unidirectional blocking diode-less solar inputs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-dropout linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2940CT-9.0/NOPB | TO-220 package (3-pin), higher thermal mass, θJA = 60°C/W (unheatsinked), rated for 0°C to 125°C junction. | Better suited for high-power, convection-cooled industrial enclosures; not surface-mount compatible. | Select when PCB space permits through-hole mounting and thermal dissipation exceeds SOT-223 capability. |
| TPS7A4700RGWR | Ultra-low-noise (4 μVrms), adjustable output, 1 A, but no reverse-battery or mirror-insertion protection. | Used in precision analog signal chains (e.g., audio, instrumentation), not automotive harsh environments. | Choose only if noise performance is prioritized over fault protection - requires external reverse-polarity diode. |
Compared with LM2940CT-9.0/NOPB, the LM2940IMPX-9.0 offers surface-mount compatibility and lower profile but requires careful PCB thermal design; compared with TPS7A4700RGWR, it trades noise performance for integrated automotive-grade fault resilience - no external protection components needed.
Availability
LM2940IMPX-9.0 is available at Aetrix Electronics and suitable for automotive body electronics, industrial programmable logic controllers, and off-grid energy management systems requiring stable component supply with guaranteed long-term availability and automotive-grade qualification.
Supply support for LM2940IMPX-9.0 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 connectivity technologies with over 50 years of power management innovation.
The LM2940 series was developed specifically for automotive and industrial applications demanding ruggedness against reverse polarity, load dump, and thermal stress - targeting 12 V and 24 V battery-fed systems.
FAQ
What is the minimum input voltage required for stable regulation of LM2940IMPX-9.0?
The LM2940IMPX-9.0 requires a minimum input voltage of 10.5 V to maintain 9.0 V output across full load (1 A) and temperature range. This accounts for its 0.5 V typical dropout voltage plus margin for variation - operation below 10.5 V risks dropout and output collapse. At light loads (<100 mA), dropout drops to 110 mV, allowing regulation down to ~9.1 V.
Does LM2940IMPX-9.0 require an external capacitor on the output pin?
Yes, LM2940IMPX-9.0 requires a minimum 22 μF output capacitor with tightly controlled ESR (0.1–1 Ω) placed adjacent to the device. Aluminum electrolytic, tantalum, or polymer capacitors meeting this ESR range are acceptable. Failure to meet ESR limits causes instability and oscillation - no bypass capacitor can substitute for this requirement.
Can LM2940IMPX-9.0 survive reverse battery connection in automotive applications?
Yes, LM2940IMPX-9.0 is rated for −30 V DC reverse input voltage continuously and survives −75 V transients ≤100 ms. This eliminates the need for external series diodes or MOSFET-based protection circuits - a key differentiator for automotive body electronics where reverse jump-starts are common.
What thermal considerations apply to LM2940IMPX-9.0 in SOT-223 packaging?
LM2940IMPX-9.0 in SOT-223 has θJA = 174°C/W with no PCB copper; thermal performance depends critically on soldering the exposed thermal pad to ≥1-in² of 1-oz copper. With proper layout, θJA improves to ~74°C/W. At 1 A load and 15 V input, power dissipation is ~6 W - requiring thermal design to keep junction temperature ≤125°C.
Is LM2940IMPX-9.0 pin-compatible with other LM2940 variants?
No - LM2940IMPX-9.0 (SOT-223, 4-pin) is not pin-compatible with TO-220 (3-pin) or DDPAK (3-pin) versions of the LM2940 family. Pin 4 (GND) in the SOT-223 variant provides dedicated signal ground separation from the thermal tab (Pin 2), a layout distinction absent in 3-pin packages. PCB redesign is required for substitution.
LM2940IMPX-9.0 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-261-4, TO-261AA
- 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):
- 9V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 1V @ 1A
- Current - Output:
- 1A
- Current - Quiescent (Iq):
- 10 mA
- Current - Supply (Max):
- 15 mA
- PSRR:
- 64dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature, Reverse Polarity, Short Circuit
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-223-4
LM2940IMPX-9.0 FAQ
1.How can I place an order for LM2940IMPX-9.0 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2940IMPX-9.0 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 LM2940IMPX-9.0 reliable?
The price and inventory of LM2940IMPX-9.0 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2940IMPX-9.0 is usually 5 days.
3.What payment methods are accepted for LM2940IMPX-9.0?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2940IMPX-9.0 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2940IMPX-9.0?
LM2940IMPX-9.0 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2940IMPX-9.0 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 LM2940IMPX-9.0?
For technical support, including LM2940IMPX-9.0 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2940IMPX-9.0 requirements.
6.How does Aetrix verify that LM2940IMPX-9.0 is sourced from the original manufacturer or authorized distributors?
All LM2940IMPX-9.0 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 LM2940IMPX-9.0 meets industry standards.
7.What is the process for return or replacement of LM2940IMPX-9.0?
All LM2940IMPX-9.0 units undergo pre-shipment inspection (PSI). If there is an issue with LM2940IMPX-9.0, 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 LM2940IMPX-9.0 part is unused and in its original packaging.
Return procedure for LM2940IMPX-9.0:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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