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STMicroelectronics L4937NL
- Part No.:
- L4937NL
- Manufacturer:
- STMicroelectronics
- Package:
- Heptawatt-7 (Vertical, Bent and Staggered Leads)
- Datasheet:
-
L4937NL.pdf
- Description:
- IC REG LIN 5V 7HEPTAWATT
- Quantity:
- Payment:
- Shipping:
Inventory:1,413
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Product details
Overview
L4937NL from STMicroelectronics is a dual monolithic low-dropout voltage regulator IC designed for automotive microcontroller power systems, featuring a precision 5V ±2% standby output (VO1), a tracked 500mA main output (VO2) with enable/disable control, <0.4V dropout at VO1, and integrated power-on reset with external capacitor–defined delay. It operates up to 40V transient supply and delivers stable dual-rail power in engine control units and body electronics.
For engineers reviewing the L4937NL datasheet, L4937NL pinout, L4937NL application, or L4937NL equivalent, key selection criteria include tracked dual-output regulation, standby-mode quiescent current (<250µA), thermal/short-circuit protection, and automotive-grade transient tolerance (40V).
Technical Context
The L4937NL integrates two independent LDO regulators: VO1 uses an isolated-collector vertical PNP for ultra-low dropout (0.25V max at 50mA) and operation down to 2V input; VO2 tracks VO1 as reference and supports 500mA load with disable via TTL-compatible EN pin (VENH ≥2.4V, VENL ≤1.5V).
Its on-chip reset circuit monitors VO1, triggering a programmable delay pulse (tRD = CT × 2V / 2µA) upon drop below 4.7V threshold with 100mV hysteresis; reset reaction time (tRR) scales with CT value to enhance noise immunity in noisy automotive environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VO1 Output Voltage | 5.00 V ±2% - precision standby rail for MCU core logic and real-time clock backup |
| VO2 Tracking Error | ±25 mV - ensures tight regulation of main 500mA output relative to VO1 across load/temperature |
| VDP1 Dropout (VO1) | 0.4 V max at 50mA - enables operation with minimal headroom (e.g., 5.4V input → 5.0V out) |
| IQSB Quiescent Current | 210–340 µA - ultra-low standby consumption critical for battery-powered sleep modes |
| Transient Supply Voltage | 40 V for <1 s - withstands automotive load-dump pulses without shutdown or damage |
| Reset Threshold | 4.7 V with 100 mV hysteresis - prevents false resets during brief VO1 dips near regulation limit |
| Thermal Protection | Integrated shutdown at Tj >150°C - safeguards against sustained overload or poor heatsinking |
Pinout & Package
Package: Heptawatt (7-pin single-in-line, SIP-7), thermally enhanced with Rthj-case = 3°C/W, suitable for PCB mounting with heatsink tab (pin 7).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 – VO1 | Standby Output | 5V ±2% regulated output (50mA max); powers MCU standby circuits and RTC |
| 2 – GND | Ground Reference | Common return for both regulators and reset circuit; requires low-impedance PCB plane |
| 3 – VS | Main Supply Input | Accepts 6–25V DC or 40V transient; feeds both regulators and internal bias circuitry |
| 4 – EN | Enable Control | TTL-compatible input: LOW disables VO2; HIGH (≥2.4V) enables VO2 tracking VO1 |
| 5 – VO2 | Main Output | 500mA tracked output; voltage follows VO1 ±25mV; disabled when EN = LOW |
| 6 – RES | Reset Output | Open-collector active-low signal; pulled low when VO1 < 4.7V (with hysteresis) |
| 7 – TAB | Thermal Pad / Case | Internally connected to GND; must be soldered to heatsink area for thermal management |
Key Features
| Feature | Design Value |
|---|---|
| Dual LDO Architecture | Independent PNP-based regulators: VO1 (50mA, 0.4V dropout), VO2 (500mA, 0.6V dropout), sharing single input |
| Tracking Regulation | VO2 maintains ±25mV accuracy vs. VO1 across full load range (5–500mA) and temperature (–40°C to +125°C) |
| Programmable Reset Delay | tRD set by external CT (e.g., 100nF → 100ms nominal); enables precise power sequencing in multi-rail systems |
| Automotive Transient Robustness | Rated for 40V/1s load dump; no external TVS required in most 12V vehicle applications |
| Low-Power Standby Mode | IQSB < 340µA with VO2 disabled - extends battery life in always-on vehicle modules (e.g., CAN gateways) |
Applications
| Engine Control Unit (ECU) | Body Control Module (BCM) |
|---|---|
Use Scenario: Powering 5V MCU core, CAN transceiver, and sensor interface in gasoline/diesel engine management. IC Role / Device Role / Timing Role: Dual-rail LDO regulator providing isolated standby (VO1) and main (VO2) supplies with synchronized reset signaling. Use Value: Enables reliable cold-cranking operation (down to 2V input) and withstands alternator load-dump transients without brownout. | Use Scenario: Supplying door module MCU, LIN transceiver, and LED drivers in vehicle interior lighting and lock control. IC Role / Device Role / Timing Role: Primary power IC delivering tracked 5V rails and generating system reset pulse upon battery undervoltage. Use Value: Eliminates need for discrete reset IC and second LDO; reduces BOM count while meeting ISO 7637-2 pulse test requirements. |
| Infotainment Head Unit | Telematics Control Unit (TCU) |
Use Scenario: Providing clean 5V power to audio DSP, display controller, and USB PHY in dashboard infotainment systems. IC Role / Device Role / Timing Role: Dual-output regulator with VO2 disable capability to reduce idle power during screen-off states. Use Value: Achieves <340µA system standby current, extending battery runtime during vehicle parking mode. | Use Scenario: Powering cellular modem, GNSS receiver, and secure boot MCU in connected vehicle telematics platforms. IC Role / Device Role / Timing Role: Regulator with integrated reset monitoring VO1 to ensure firmware integrity after battery recovery. Use Value: Prevents corrupted boot sequences by holding reset until VO1 stabilizes above 4.7V post-ignition. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output automotive LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS7B6750QPWPRQ1 | Single 500mA LDO with enable; no standby rail or tracking; includes watchdog timer | Requires external 5V standby source; lacks integrated reset with programmable delay | Choose when system already has separate 5V standby supply and needs watchdog supervision |
| MC33FS4500A | Dual LDO (50mA + 500mA) with SPI configuration; higher quiescent current (1.2mA) in standby | Configurable via SPI (e.g., adjustable reset threshold); requires MCU interface overhead | Choose when dynamic reconfiguration or diagnostics are needed over fixed-function simplicity |
Compared with TPS7B6750QPWPRQ1 and MC33FS4500A, the L4937NL offers unique fixed-ratio tracking, sub-250µA standby IQ, and analog-programmable reset delay-making it optimal for cost-sensitive, high-reliability automotive modules where SPI complexity or external reset ICs are undesirable.
Availability
L4937NL is available at Aetrix Electronics and suitable for engine control units, body control modules, infotainment head units, and telematics control units requiring stable component supply across automotive production lifecycles.
Supply support for L4937NL 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 headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management ICs with broad manufacturing and qualification expertise.
The L4937NL belongs to ST's automotive-grade linear regulator product line, engineered specifically for robust dual-rail power delivery in engine bay and chassis-mounted electronic control units under harsh electrical and thermal conditions.
FAQ
What is the maximum allowable input voltage for continuous operation?
The L4937NL supports continuous DC supply voltage up to 25V (VS ≤25V). Its absolute maximum rating allows 40V for transients lasting less than 1 second-such as automotive load-dump events-but sustained operation above 25V risks thermal overstress and is not recommended per datasheet specifications.
Can VO2 be configured to output a voltage other than 5V?
Yes-VO2 can be adjusted above 5V using an external resistor divider between VO2, ADJ, and GND, as noted in the functional description. The base tracking mode fixes VO2 to VO1, but the ADJ pin enables programmable higher output (e.g., 8V or 12V) while retaining enable/disable and protection features.
How is the reset delay time calculated and what capacitor value yields 200ms?
Reset delay tRD = CT × 2V / 2µA = CT × 10⁶ seconds. For 200ms, solve CT = 200×10⁻³ / 10⁶ = 200nF. A 200nF ceramic capacitor (X7R, 10V rating) placed between RES and GND yields nominal 200ms delay, confirmed by the tRD equation and typical performance curves in the datasheet.
Is the thermal pad (pin 7) electrically isolated or connected internally?
The Heptawatt thermal tab (pin 7) is internally connected to GND, not isolated. It must be soldered to a grounded copper pour or heatsink for effective thermal conduction. Electrical isolation would compromise thermal resistance (Rthj-case = 3°C/W), and the datasheet mechanical drawing confirms GND connectivity.
L4937NL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- Heptawatt-7 (Vertical, Bent and Staggered Leads)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 2
- Voltage - Input (Max):
- 25V
- Voltage - Output (Min/Fixed):
- 5V, Tracking
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.4V @ 50mA, 0.6V @ 500mA
- Current - Output:
- 50mA, 500mA
- Current - Quiescent (Iq):
- -
- Current - Supply (Max):
- -
- PSRR:
- -
- Control Features:
- Enable, Reset
- Protection Features:
- Over Temperature, Short Circuit
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 7-HEPTAWATT
L4937NL FAQ
1.How can I place an order for L4937NL through Aetrix?
Please submit a Request for Quotation (RFQ) for L4937NL 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 L4937NL reliable?
The price and inventory of L4937NL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L4937NL is usually 5 days.
3.What payment methods are accepted for L4937NL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L4937NL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L4937NL?
L4937NL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L4937NL 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 L4937NL?
For technical support, including L4937NL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L4937NL requirements.
6.How does Aetrix verify that L4937NL is sourced from the original manufacturer or authorized distributors?
All L4937NL 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 L4937NL meets industry standards.
7.What is the process for return or replacement of L4937NL?
All L4937NL units undergo pre-shipment inspection (PSI). If there is an issue with L4937NL, 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 L4937NL part is unused and in its original packaging.
Return procedure for L4937NL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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