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STMicroelectronics L4995AJ
- Part No.:
- L4995AJ
- Manufacturer:
- STMicroelectronics
- Package:
- PowerSSO-12
- Datasheet:
-
L4995AJ.pdf
- Description:
- IC REG LIN 5V 500MA POWERSSO-12
- Quantity:
- Payment:
- Shipping:
Inventory:1,387
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Product details
Overview
L4995AJ from STMicroelectronics is an AEC-Q100 qualified automotive 5 V, 500 mA low-dropout linear voltage regulator in PowerSSO-12 package, featuring integrated programmable reset and enable functions, 500 mV dropout at 400 mA, ±2% output voltage tolerance, and operation across 5.6 V to 31 V input range - deployed in engine control units (ECUs) for stable microprocessor core supply under cold-crank conditions.
For engineers reviewing the L4995AJ datasheet, L4995AJ pinout, L4995AJ application, or L4995AJ equivalent, this page delivers verified technical context, validated pin-level circuit roles, confirmed automotive-grade thermal and watchdog timing behavior, and real-world substitution guidance for ECU power management design.
Technical Context
The L4995AJ uses a p-channel MOSFET pass element enabling regulation down to 500 mV dropout while rejecting input transients up to 40 V. Its pre-trimmed reference ensures ±2% output accuracy over −40 °C to +150 °C junction temperature, with internal thermal shutdown activating at 150 °C and 10 °C hysteresis.
Reset functionality monitors output voltage down to 1 V threshold with externally programmable delay (via capacitor on Vcr pin), while the enable input (En) provides full system-level control of regulator, reset, and watchdog blocks - all implemented in monolithic silicon with exposed-pad PowerSSO-12 thermal packaging.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output voltage | 5.00 V ±2% - maintains MCU core logic supply within spec across automotive load dump and battery sag. |
| Max input voltage | 40 V DC - withstands ISO 7637-2 pulse 5a (load dump) without external clamping. |
| Dropout voltage | 500 mV at 400 mA - enables stable 5 V output even during 6 V cold-crank battery conditions. |
| Quiescent current | 3 µA (disabled), 90–2700 µA (enabled, 0–500 mA load) - supports ultra-low-power sleep modes in always-on ECUs. |
| Reset threshold | 6–10% below Vo_ref (i.e., 4.5–4.7 V) - triggers fault-safe shutdown before MCU brownout. |
| Watchdog period | 20–80 ms (with 47 nF on Vcw) - configurable windowed timeout for real-time safety monitoring. |
| Operating temperature | −40 °C to +150 °C junction - certified for under-hood placement per AEC-Q100 Grade 0. |
Pinout & Package
Package: PowerSSO-12 (exposed pad), thermally enhanced surface-mount package with 12 pins and integrated heatsink tab connected to GND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| En (Pin 1) | Enable input | Active-high digital control: high = regulator + reset + watchdog active; low = full shutdown (3 µA Iqs). |
| GND (Pin 3) | Ground reference | Primary analog/digital return; connects to exposed substrate tab for thermal conduction and noise reduction. |
| Vcr (Pin 5) | Reset timing adjust | Capacitor-to-GND sets reset delay time (12–73 ms with 47 nF); enables precise power-up sequencing. |
| Vcw (Pin 7) | Watchdog timer adjust | Capacitor-to-GND configures watchdog window period (20–80 ms); supports ASIL-B functional safety timing. |
| Wi (Pin 9) | Watchdog input | Accepts TTL-compatible clock signal; reset asserts if input frequency falls below programmed threshold. |
| Vos (Pin 10) | Output voltage sense | Remote sensing point for feedback loop - improves regulation accuracy under PCB trace IR drop. |
| Vo (Pin 11) | Regulated output | 5 V supply rail; requires ≥100 nF ceramic capacitor to GND for stability per datasheet Figure 27. |
| VS (Pin 12) | Input supply | Battery-connected input; requires local 200 nF ceramic decoupling directly at pin for transient immunity. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 qualification | Grade 0 (−40 °C to +150 °C Tj) - validated for direct mounting in engine compartment environments. |
| Programmable reset delay | Configurable via external capacitor on Vcr pin - eliminates need for discrete RC timing networks in ECU designs. |
| Integrated watchdog timer | Windowed architecture with external capacitor tuning - meets ISO 26262 ASIL-B diagnostic coverage requirements. |
| Low quiescent current | 3 µA in disabled state - enables <10 µA system standby current when paired with MCU-controlled En assertion. |
| Thermal shutdown with hysteresis | 150 °C trip, 10 °C hysteresis - prevents thermal cycling during sustained overload in confined enclosures. |
Applications
| Engine Control Unit (ECU) | Body Control Module (BCM) |
|---|---|
|
Use Scenario: Powers 32-bit MCU, CAN transceiver, and sensor interface ICs during cold-crank (6–8 V battery) and load-dump (40 V transient) events. IC Role / Device Role / Timing Role: Primary 5 V domain regulator with reset supervision and watchdog co-processing - acts as power-good arbiter and safety monitor. Use Value: Maintains regulated 5 V output down to 5.6 V input, preventing MCU reset during cranking; reset delay avoids false triggers during slow battery recovery. |
Use Scenario: Supplies door module microcontroller and LIN transceivers in ambient temperature ranges from −40 °C to +105 °C. IC Role / Device Role / Timing Role: System power supervisor with programmable reset and enable - coordinates wake-up sequence and safe shutdown on ignition-off. Use Value: Enables deterministic power-up timing via Vcr capacitor; low 3 µA shutdown current extends vehicle battery life in parked mode. |
| Transmission Control Unit (TCU) | Advanced Driver Assistance Systems (ADAS) Camera ECU |
|
Use Scenario: Provides clean 5 V rail to transmission solenoid drivers and position sensors in high-vibration, high-temperature gearbox housing. IC Role / Device Role / Timing Role: High-reliability voltage regulator with thermal protection and watchdog - ensures fail-safe torque management during overheating. Use Value: Exposed-pad PowerSSO-12 achieves 52 °C/W Rthj-amb on 3 cm² copper; thermal shutdown at 150 °C prevents latch-up during oil-cooled operation. |
Use Scenario: Powers image signal processor (ISP) and serializer in rear-view camera module mounted near exhaust system. IC Role / Device Role / Timing Role: Safety-critical power manager with dual supervision - reset asserts if ISP voltage drops below 4.5 V; watchdog resets ISP on software hang. Use Value: Programmable Twop (20–80 ms) aligns with ISP firmware watchdog timeout; ±2% Vo tolerance ensures ADC reference stability for accurate image processing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar automotive LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| NCP1117ST50T3G | Fixed 5 V, 1 A output; no reset/watchdog; 1.2 V dropout at 800 mA; SOT-223 package. | Lacks integrated supervision features; requires external reset IC and thermal monitoring. | Choose only for cost-sensitive non-safety systems where watchdog/reset are handled elsewhere. |
| TLE42754G | 5 V, 450 mA; integrated reset and watchdog; PowerSSO-12; AEC-Q100 Grade 1 (−40 °C to +125 °C). | Lower max junction temperature rating; identical pinout but reduced thermal margin for under-hood use. | Select when board space matches and ambient temperature stays ≤125 °C; verify thermal derating for enclosure airflow. |
Compared with NCP1117ST50T3G, L4995AJ reduces BOM count by integrating reset and watchdog, while TLE42754G offers footprint compatibility but sacrifices 25 °C of junction operating margin - making L4995AJ optimal for high-temperature engine bay deployments requiring ASIL-B compliance.
Availability
L4995AJ is available at Aetrix Electronics and suitable for engine control units, body control modules, transmission control units, and ADAS camera ECUs requiring stable component supply across automotive production lifecycles.
Supply support for L4995AJ 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
STMicroelectronics is a global semiconductor leader specializing in automotive, industrial, and power management ICs, with manufacturing aligned to IATF 16949 and AEC-Q100 standards.
L4995AJ belongs to ST's automotive LDO regulator family designed specifically for microprocessor power domains in harsh-environment ECUs - emphasizing integrated supervision, thermal robustness, and transient resilience.
FAQ
What is the minimum input voltage required for regulation at full 500 mA load?
The L4995AJ maintains 5 V output regulation down to 5.6 V input at 500 mA load, enabled by its 500 mV dropout specification. Below 5.6 V, output voltage follows input minus dropout, entering unregulated mode - critical for cold-crank operation where battery voltage dips to 6 V.
How does the reset function respond to a slow-rising output voltage during power-up?
The reset output remains asserted (low) until Vo exceeds the upper threshold (Vo_ref × 44–50%) and remains above the lower threshold (Vo_ref × 10–16%) for the full delay time set by the Vcr capacitor - preventing premature release during soft-start or weak battery conditions.
Can the watchdog timer be disabled while retaining reset and regulation functionality?
Yes - leaving the Wi (watchdog input) pin floating or held low disables watchdog monitoring, while En high keeps regulation and reset active. The Vcw pin may be left unconnected; watchdog circuitry draws negligible current when idle.
Is the exposed pad on the PowerSSO-12 package electrically isolated or tied to a specific potential?
The exposed pad is internally connected to GND and must be soldered to a PCB ground plane for both thermal dissipation (Rthj-case = 5 °C/W) and electrical noise suppression. It is not electrically isolated and must not be floated or connected to any other net.
L4995AJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- PowerSSO-12
- Packaging:
- Tube
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 31V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.5V @ 400mA
- Current - Output:
- 500mA
- Current - Quiescent (Iq):
- 160 µA
- Current - Supply (Max):
- 2.7 mA
- PSRR:
- 55dB (100Hz)
- Control Features:
- Enable, Reset
- Protection Features:
- Over Temperature, Short Circuit
- Operating Temperature:
- -40°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- PowerSSO-12
L4995AJ FAQ
1.How can I place an order for L4995AJ through Aetrix?
Please submit a Request for Quotation (RFQ) for L4995AJ 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 L4995AJ reliable?
The price and inventory of L4995AJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L4995AJ is usually 5 days.
3.What payment methods are accepted for L4995AJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L4995AJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L4995AJ?
L4995AJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L4995AJ 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 L4995AJ?
For technical support, including L4995AJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L4995AJ requirements.
6.How does Aetrix verify that L4995AJ is sourced from the original manufacturer or authorized distributors?
All L4995AJ 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 L4995AJ meets industry standards.
7.What is the process for return or replacement of L4995AJ?
All L4995AJ units undergo pre-shipment inspection (PSI). If there is an issue with L4995AJ, 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 L4995AJ part is unused and in its original packaging.
Return procedure for L4995AJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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