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STMicroelectronics L4938EPD13TR
- Part No.:
- L4938EPD13TR
- Manufacturer:
- STMicroelectronics
- Package:
- 20-SOIC (0.433", 11.00mm Width) Exposed Pad
- Datasheet:
-
L4938EPD13TR.pdf
- Description:
- IC REG LINEAR POS ADJ POWERSO20
- Quantity:
- Payment:
- Shipping:
Inventory:953
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Product details
Overview
L4938EPD13TR from STMicroelectronics is a monolithic dual-voltage regulator IC designed for automotive microcomputer power supply systems, featuring two low-dropout outputs (5 V ±1% @ 100 mA and 5 V ±2% @ 400 mA), adjustable reset threshold (3.8–4.7 V), and integrated sense comparator with -5 V transient-protected EN/SI inputs.
For engineers reviewing the L4938EPD13TR datasheet, L4938EPD13TR pinout, L4938EPD13TR application, or L4938EPD13TR equivalent, this device supports critical automotive subsystems requiring stable dual-rail biasing, power-on reset supervision, and input voltage monitoring under harsh transients up to 40 V.
Technical Context
The L4938EPD13TR integrates two independent LDO regulators: OUT1 uses an isolated-collector vertical PNP transistor enabling dropout operation down to 3 V input while maintaining 5 V ±1% regulation at 100 mA; OUT2 employs identical topology rated for 400 mA with ADJ feedback allowing fixed or adjustable output via external resistor divider.
Its functional blocks include a programmable reset generator (threshold set by PR-to-GND resistor, delay controlled by CT capacitor), a sense comparator referenced to 1.16 V with ±30 mV hysteresis, and thermal shutdown that disables OUT2 ~10 K before OUT1 to preserve standby functionality during overload.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| OUT1 Voltage | 5 V ±1% at 100 mA load - ensures stable MCU core supply under full load and temperature variation |
| OUT2 Voltage | 5 V ±2% at 400 mA load - powers peripheral ICs, sensors, or CAN transceivers without external pass devices |
| Quiescent Current | 65 µA in standby mode - enables always-on vehicle modules meeting ISO 16750-2 quiescent current requirements |
| Reset Threshold Range | 3.8 V to 4.7 V (programmable via PR resistor) - allows precise brown-out detection aligned with MCU VDD tolerance |
| Supply Voltage Range | 5 V to 28 V DC, with 40 V transient tolerance - survives automotive load-dump and cold-crank conditions |
| Sense Input Range | -20 V to +20 V with ±1 mA current limit - supports direct connection to battery or alternator sensing points |
| Thermal Shutdown | OUT2 disables at ~155 °C, OUT1 at ~165 °C - prevents thermal runaway while preserving critical logic supply |
Pinout & Package
Package: PowerSO-20 - thermally enhanced surface-mount package with exposed die pad for improved heat dissipation in automotive PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VS1 | Input supply for 100 mA regulator, reset, and sense circuits | Primary bias rail; powers internal reference, reset comparator, and OUT1 - must be decoupled per layout guidelines |
| VS2 | Input supply for 400 mA regulator | Dedicated high-current path; enables independent transient handling for power-hungry peripherals |
| OUT1 | 100 mA regulated output (5 V ±1%) | Stable MCU core voltage source; maintains regulation down to 3 V input, supporting cold-crank operation |
| OUT2 | 400 mA regulated output (5 V ±2%) | Main system rail; disable-controlled via EN pin to reduce sleep-mode current in infotainment or body control modules |
| ADJ | Feedback node for OUT2 regulation | Enables output voltage adjustment (e.g., 3.3 V) using external resistor divider; capacitive loading prohibited |
| EN | Active-low enable for OUT2 | Pull-high to disable OUT2; withstands -5 V transients - eliminates need for external level-shifting circuitry |
| SI | Sense input for comparator | Monitors external voltage (e.g., battery or pre-regulator); triggers SO output when below 1.16 V threshold |
| PR | Reset threshold programming | Resistor-to-GND sets reset point between 3.8 V and 4.7 V - enables custom brown-out behavior without firmware change |
| CT | Reset delay capacitor connection | External capacitor (e.g., 47 nF) sets nominal reset pulse width of 60–140 ms - ensures reliable MCU initialization |
| RES | Open-drain reset output | Asserts low when OUT1 falls below programmed threshold; sinks 6 mA - directly drives MCU RESET pin |
| SO | Sense output | Open-drain signal indicating SI < 1.16 V - used for low-battery warning or system-level fault escalation |
| GND | Ground reference (8 pins) | Multiple dedicated ground pins minimize ground bounce and improve noise immunity in noisy automotive environments |
Key Features
| Feature | Design Value |
|---|---|
| Enable and Sense Input Protection | Withstands -5 V transients on EN/SI pins - eliminates need for external TVS diodes in cost-sensitive designs |
| Adjustable Reset Threshold | Programmable from 3.8 V to 4.7 V using single resistor - aligns reset behavior precisely with target MCU's VDD min specification |
| Ultra-Low Standby Quiescent Current | 65 µA typical at 14 V - meets OEM requirements for <100 µA sleep current in always-on vehicle networks |
| Dual Independent Thermal Shutdown | OUT2 disables ~10 K before OUT1 - preserves MCU operation during localized overheating (e.g., high ambient + heavy peripheral load) |
| Transient-Tolerant Supply Operation | Operates continuously up to 40 V transient input - sustains function during ISO 7637-2 Pulse 5a load-dump events without latch-up |
Applications
| Engine Control Unit (ECU) | Body Control Module (BCM) |
|---|---|
Use Scenario: Powers 32-bit MCU core and CAN controller in gasoline/diesel engine management systems exposed to wide temperature (-40 °C to 125 °C) and electrical stress (load dump, reverse battery). IC Role / Device Role / Timing Role: Dual-rail regulator providing isolated 5 V supplies: OUT1 for MCU VDD, OUT2 for sensor interface and actuator drivers; RES synchronizes MCU boot after battery reconnection. Use Value: Maintains 5 V ±1% at OUT1 during cold-crank (input drops to 3 V), ensuring uninterrupted ECU operation without brown-out resets. | Use Scenario: Supplies door module microcontroller, LIN transceivers, and window motor drivers in centralized body electronics architecture. IC Role / Device Role / Timing Role: OUT2 powers high-current loads (e.g., mirror heaters); EN pin disables OUT2 during sleep mode; SI monitors battery voltage for wake-up trigger. Use Value: Reduces system sleep current to <100 µA via OUT2 disable and 65 µA quiescent draw - extends battery life in parked vehicle state. |
| Advanced Driver Assistance Systems (ADAS) Camera Module | Infotainment Head Unit |
Use Scenario: Provides clean 5 V rails to image sensor, ISP, and serializer in rear-view or surround-view camera nodes mounted near exhaust or wheel wells. IC Role / Device Role / Timing Role: OUT1 powers noise-sensitive image sensor analog block; OUT2 powers digital ISP and serializer; SO signals low-battery condition to host processor. Use Value: Low dropout and thermal robustness prevent thermal shutdown during sustained 85 °C ambient - avoids video dropouts in hot parking scenarios. | Use Scenario: Regulates power for application processor, audio codec, and display driver in dashboard-mounted infotainment units subject to repeated ignition cycles. IC Role / Device Role / Timing Role: RES output provides hardware reset to AP during key-on; PR/CT configuration ensures 100 ms minimum reset pulse - guarantees deterministic boot sequence. Use Value: Programmable reset threshold (e.g., 4.2 V) prevents spurious resets during alternator ripple or brief dips - improves user experience and system reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output automotive voltage regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLF4938BQV | Integrated watchdog timer and SPI interface; higher quiescent current (120 µA); same PowerSO-20 package | Supports ASIL-B diagnostic coverage; requires firmware integration for reset configuration | Select when functional safety compliance (ISO 26262) or dynamic reset threshold adjustment is required |
| NCP102S2DR2G | Single 5 V output (300 mA); no reset/sense functions; SO-8 package; lower cost | Lacks dual-rail capability and supervisory features - suitable only for non-critical subsystems | Select only for cost-driven body electronics where reset supervision and secondary rail are omitted |
Compared with TLF4938BQV, L4938EPD13TR offers lower quiescent current and simpler analog configuration but lacks diagnostics; versus NCP102S2DR2G, it delivers dual regulated outputs and comprehensive automotive protection at higher BOM cost and complexity.
Availability
L4938EPD13TR is available at Aetrix Electronics and suitable for automotive engine control, body electronics, ADAS camera modules, and infotainment systems requiring stable component supply across extended temperature and lifetime requirements.
Supply support for L4938EPD13TR 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 scale and AEC-Q100 qualification expertise.
The L4938 series belongs to ST's automotive power management portfolio, engineered specifically for microcomputer-supplied systems in harsh environments - emphasizing transient resilience, ultra-low standby current, and integrated supervision functions.
FAQ
What is the maximum allowable input voltage for continuous operation?
The L4938EPD13TR supports continuous DC operation from 5 V to 28 V. Its absolute maximum rating allows transient exposure up to 40 V for durations under 400 ms, making it suitable for automotive load-dump conditions per ISO 7637-2 Pulse 5a. Sustained operation above 28 V risks permanent damage and violates specified operating limits.
Can OUT2 be configured for an output voltage other than 5 V?
Yes - connecting an external resistor divider between OUT2 and ADJ enables adjustable output voltages. With RADJ = 60 kΩ to 150 kΩ and VOUT1 = 4.95–5.05 V, outputs such as 3.3 V are achievable. The datasheet provides the exact formula: VOUT2 = VOUT1 × (1 + R1E/R2E + RADJ/R2E). Capacitive loading on ADJ must be avoided to maintain loop stability.
How does the sense comparator function in a typical automotive design?
The SI pin accepts voltages from -20 V to +20 V and compares them to a 1.16 V internal reference. When SI falls below this threshold, the open-drain SO pin pulls low. In practice, this is used to monitor battery voltage via a resistor divider (e.g., 100 kΩ/10 kΩ for 12 V → 1.09 V), triggering low-battery warnings or wake-up events in sleep mode.
Is thermal derating required when operating at 400 mA output current?
Yes - at 400 mA load and ambient temperatures above 80 °C, power dissipation exceeds the SO-20 package's 50 °C/W thermal resistance limit. The PowerSO-20 package (Rthj-case < 2 °C/W) is mandatory for full 400 mA operation across -40 °C to 125 °C. Layout must include ≥8 cm² copper pour under the exposed pad for effective heat transfer.
L4938EPD13TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 20-SOIC (0.433", 11.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Adjustable (Fixed)
- Number of Regulators:
- 2
- Voltage - Input (Max):
- 28V
- Voltage - Output (Min/Fixed):
- 4.9V (5V)
- Voltage - Output (Max):
- 5.1V
- Voltage Dropout (Max):
- 0.4V @ 100mA, 0.6V @ 400mA
- Current - Output:
- 100mA, 400mA
- Current - Quiescent (Iq):
- -
- Current - Supply (Max):
- -
- PSRR:
- -
- Control Features:
- Enable, Reset
- Protection Features:
- Over Temperature
- Operating Temperature:
- -40°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- PowerSO-20
L4938EPD13TR FAQ
1.How can I place an order for L4938EPD13TR through Aetrix?
Please submit a Request for Quotation (RFQ) for L4938EPD13TR 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 L4938EPD13TR reliable?
The price and inventory of L4938EPD13TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L4938EPD13TR is usually 5 days.
3.What payment methods are accepted for L4938EPD13TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L4938EPD13TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L4938EPD13TR?
L4938EPD13TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L4938EPD13TR 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 L4938EPD13TR?
For technical support, including L4938EPD13TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L4938EPD13TR requirements.
6.How does Aetrix verify that L4938EPD13TR is sourced from the original manufacturer or authorized distributors?
All L4938EPD13TR 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 L4938EPD13TR meets industry standards.
7.What is the process for return or replacement of L4938EPD13TR?
All L4938EPD13TR units undergo pre-shipment inspection (PSI). If there is an issue with L4938EPD13TR, 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 L4938EPD13TR part is unused and in its original packaging.
Return procedure for L4938EPD13TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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