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Texas Instruments LMR38020FDDAR
- Part No.:
- LMR38020FDDAR
- Manufacturer:
- Texas Instruments
- Package:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Datasheet:
-
LMR38020FDDAR.pdf
- Description:
- IC REG BUCK ADJ 2A 8SOPWR
- Quantity:
- Payment:
- Shipping:
Inventory:1,489
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Product details
Overview
LMR38020FDDAR from Texas Instruments is a 4.2-V to 80-V, 2-A synchronous buck DC/DC converter in an 8-pin HSOIC PowerPAD package, featuring forced PWM (FPWM) operation, ±1.0% reference voltage accuracy at 25°C, and 40-µA non-switching quiescent current - designed for rugged industrial power rails in MHEV/EV systems and factory automation.
For engineers reviewing the LMR38020FDDAR datasheet, LMR38020FDDAR pinout, LMR38020FDDAR application, or LMR38020FDDAR equivalent, key selection criteria include FPWM mode for constant-frequency light-load regulation, 97% max duty cycle for ultra-low dropout, precision enable with 1.1–1.4 V turn-on threshold, and integrated thermal shutdown at 163°C.
Technical Context
The LMR38020FDDAR employs fixed-frequency peak-current mode control with internal compensation, enabling stable regulation across 1–75 V output using only two external resistors and standard passive components. Its FPWM variant eliminates PFM-mode output ripple while maintaining tight ±1.5% output voltage regulation over full load and temperature.
It integrates high-side (303 mΩ) and low-side (133 mΩ) NMOS switches, supports frequency synchronization from 300 kHz to 2.1 MHz via RT/SYNC pin, and delivers true power-good signaling with built-in 40-µs glitch filtering and 112%/92% rising/falling thresholds referenced to FB voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.2 V to 80 V - enables direct connection to unregulated industrial bus rails and battery stacks without pre-regulation. |
| Output Current | 2 A continuous - supports mid-power subsystems such as PLC I/O modules, wireless baseband supplies, and motor control logic rails. |
| Quiescent Current | 40 µA (non-switching) - extends standby runtime in always-on industrial sensors and remote monitoring nodes. |
| Reference Voltage | 1.00 V ±1.0% at 25°C - ensures ≤±1.5% output voltage accuracy over full load and temperature in FPWM mode. |
| Switching Frequency | 200 kHz to 2.2 MHz adjustable - allows EMI-sensitive designs to avoid noise bands while optimizing efficiency vs. size trade-offs. |
| Duty Cycle Max | 97% - sustains regulation during deep input dips (e.g., 4.2 V start-up), critical for automotive cold-crank and brownout resilience. |
| Thermal Shutdown | 163°C shutdown / 150°C recovery - provides robust protection under sustained overload or poor heatsinking in enclosed enclosures. |
Pinout & Package
LMR38020FDDAR is housed in an 8-pin HSOIC (DDA) package with exposed thermal pad (PowerPAD™), measuring 4.89 mm × 3.90 mm. The package supports high-power dissipation with RθJA = 42.9°C/W (standard board) and RθJB = 13.6°C/W (board-mounted).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND | Power and analog ground | Primary return path for VIN bypass, SW node, and feedback network; must be connected directly to thermal pad and system ground plane. |
| EN | Enable input | Logic-level control with 1.1–1.4 V turn-on threshold; supports direct VIN tie or precision UVLO divider for system sequencing. |
| VIN | Main input supply | Accepts 4.2–80 V; requires low-ESR ceramic capacitor placed adjacent to pin and GND for transient suppression. |
| RT/SYNC | Frequency programming or sync input | Configurable via resistor (200–2200 kHz) or external clock (300–2100 kHz); auto-reverts to resistor mode if sync signal stops. |
| FB | Feedback input | Monitors output via resistor divider; 1.00 V reference enables precise adjustable outputs from 1 V to 75 V. |
| PG | Open-drain power-good flag | Asserts high after soft-start (4 ms delay) when VOUT is within 92–112% of target; includes 40-µs glitch filter. |
| BOOT | Bootstrap supply | Drives high-side gate via 100-nF capacitor to SW; critical for proper high-side MOSFET turn-on and efficiency. |
| SW | Switch node | Connects to power inductor; carries high di/dt switching current - requires short, wide copper pour and minimal loop area. |
Key Features
| Feature | Design Value |
|---|---|
| Forced PWM (FPWM) mode | Eliminates light-load frequency modulation, ensuring constant switching frequency and low output voltage ripple for noise-sensitive analog circuits. |
| Precision enable with UVLO | 1.1–1.4 V enable threshold enables reliable self-start from wide-input rails and programmable system-level undervoltage lockout. |
| Integrated synchronous rectification | Reduces conduction losses with 303 mΩ high-side and 133 mΩ low-side MOSFETs - no external diode or driver required. |
| Internal soft-start | 4-ms controlled ramp prevents inrush current and output overshoot during power-up, simplifying system-level reset timing. |
| Robust protection suite | Includes cycle-by-cycle current limit, hiccup-mode short-circuit response, thermal shutdown, and VIN UVLO - reduces need for external supervision. |
Applications
| Industrial Transport Power Rails | Wireless Infrastructure Baseband |
|---|---|
|
Use Scenario: Powering CAN transceivers, microcontrollers, and sensor interfaces in heavy-duty vehicle ECUs operating from 12–48 V battery systems with cold-crank dips to 4.2 V. IC Role / Device Role / Timing Role: Primary 5-V or 3.3-V point-of-load regulator delivering 2 A with FPWM mode to maintain clean supply during CAN bus arbitration and LIN communication. Use Value: 97% max duty cycle sustains regulation during 4.2-V cold-crank events; 40-µA IQ minimizes parasitic drain on auxiliary batteries during vehicle sleep modes. |
Use Scenario: Generating stable 12-V and 5-V rails for RF front-end biasing, FPGA configuration, and Ethernet PHYs in outdoor small-cell base stations exposed to wide ambient temperatures. IC Role / Device Role / Timing Role: Synchronous buck converter providing tightly regulated, low-noise intermediate supplies with spread-spectrum disabled (per LMR38020FDDAR's FPWM-only configuration) for EMI-controlled RF environments. Use Value: ±1.0% reference accuracy and FPWM operation ensure <±1.5% output stability across –40°C to +125°C junction range, meeting 3GPP thermal compliance for outdoor radios. |
| Factory Automation I/O Modules | MHEV Battery Management Subsystems |
|
Use Scenario: Supplying isolated digital I/O, analog input conditioning, and fieldbus interface ICs in modular PLC backplanes with 24-V nominal but fluctuating industrial power. IC Role / Device Role / Timing Role: High-voltage buck regulator converting 24–48 V bus to 5 V/3.3 V for real-time control logic, with PG flag used for watchdog reset coordination across distributed modules. Use Value: Open-drain PG output with 40-µs glitch filter provides reliable system reset signaling during line transients, eliminating need for external supervisor ICs. |
Use Scenario: Powering MCU, ADC, and isolated gate drivers in 48-V mild-hybrid electric vehicle battery disconnect units and DC-DC converters requiring >60-V input capability. IC Role / Device Role / Timing Role: Wide-input synchronous buck supplying 3.3-V MCU core and 5-V sensor rails from 48-V traction battery with inherent surge tolerance up to 80 V. Use Value: 80-V absolute maximum input rating and >1.5-mm creepage between VIN and GND pins meet reinforced isolation requirements for ASIL-B functional safety architectures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR38020SDDAR | Same 2-A rating and package, but uses PFM mode instead of FPWM - higher light-load efficiency but variable frequency and increased output ripple. | Better suited for battery-powered remote sensors where ultra-low IQ dominates over ripple sensitivity. | Select LMR38020SDDAR only when minimizing standby power is prioritized over EMI control or analog supply cleanliness. |
| LMR36520DRCR | Lower 65-V max input, 2-A rating, 3-MHz max frequency, and 2.5-µA IQ - uses different control architecture and smaller 10-pin WSON package. | Targets space-constrained, high-frequency designs like portable test equipment where 80-V input is unnecessary. | Choose LMR36520DRCR for compact, high-switching-frequency applications below 65 V; not suitable for 72-V industrial bus or MHEV use cases. |
Compared with LMR38020SDDAR and LMR36520DRCR, the LMR38020FDDAR uniquely balances 80-V input resilience, FPWM-mode stability, and industrial-grade thermal protection - making it the only option among the three qualified for sustained operation above 65 V with constant-frequency regulation.
Availability
LMR38020FDDAR is available at Aetrix Electronics and suitable for industrial transport power rails, wireless infrastructure baseband supplies, and factory automation I/O modules requiring stable component supply across extended temperature and voltage ranges.
Supply support for LMR38020FDDAR 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 power management technologies, with decades of expertise in high-reliability industrial and automotive power solutions.
The LMR38020FDDAR belongs to TI's SIMPLE SWITCHER® synchronous buck converter family, engineered for rugged wide-input industrial and transportation applications where input surges, cold-crank events, and long-term reliability are critical design constraints.
FAQ
What is the key functional difference between LMR38020FDDAR and LMR38020SDDAR?
The LMR38020FDDAR operates exclusively in forced PWM (FPWM) mode, ensuring constant switching frequency and minimal output voltage ripple even at light loads. In contrast, the LMR38020SDDAR uses pulse-frequency modulation (PFM), which improves light-load efficiency but introduces variable frequency and higher ripple. This makes the LMR38020FDDAR preferable for noise-sensitive analog or RF subsystems where spectral purity matters.
Does LMR38020FDDAR support external frequency synchronization?
Yes, the LMR38020FDDAR supports external clock synchronization via its RT/SYNC pin, accepting square-wave inputs from 300 kHz to 2.1 MHz. When an external clock is applied, the internal oscillator locks to its falling edge; if the clock stops, the device automatically reverts to resistor-programmed frequency mode. This capability enables EMI reduction through deterministic frequency alignment in multi-rail systems.
What is the minimum input voltage required for LMR38020FDDAR to start up and regulate?
The LMR38020FDDAR requires a minimum input voltage of 4.2 V to initiate startup and sustain regulation. Below this threshold, the device remains in undervoltage lockout (UVLO). Once operating, it can maintain regulation down to approximately 3.8 V due to its 97% maximum duty cycle - a critical feature for automotive cold-crank and brownout scenarios where input dips occur.
How does the power-good (PG) flag on LMR38020FDDAR behave during startup and fault conditions?
The LMR38020FDDAR's open-drain PG flag asserts high after a 4-ms internal soft-start delay once EN is enabled and output reaches 92% of target. It pulls low during startup, thermal shutdown, current-limit faults, or if VOUT falls below 92% or rises above 112% of the setpoint. A built-in 40-µs glitch filter prevents false triggering from transient line/load disturbances, ensuring reliable system reset signaling.
Can LMR38020FDDAR be used with a pre-biased output voltage?
Yes, the LMR38020FDDAR supports start-up into a pre-biased output, meaning it can safely begin regulation when the output rail already holds a voltage - common in hot-swap or redundant power systems. This capability avoids reverse current flow and potential damage to downstream circuitry, eliminating the need for external blocking diodes or complex sequencing controls in multi-supply architectures.
LMR38020FDDAR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.2V
- Voltage - Input (Max):
- 80V
- Voltage - Output (Min/Fixed):
- 1V
- Voltage - Output (Max):
- 75V
- Current - Output:
- 2A
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO PowerPad
LMR38020FDDAR FAQ
1.How can I place an order for LMR38020FDDAR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR38020FDDAR 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 LMR38020FDDAR reliable?
The price and inventory of LMR38020FDDAR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR38020FDDAR is usually 5 days.
3.What payment methods are accepted for LMR38020FDDAR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR38020FDDAR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR38020FDDAR?
LMR38020FDDAR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR38020FDDAR 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 LMR38020FDDAR?
For technical support, including LMR38020FDDAR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR38020FDDAR requirements.
6.How does Aetrix verify that LMR38020FDDAR is sourced from the original manufacturer or authorized distributors?
All LMR38020FDDAR 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 LMR38020FDDAR meets industry standards.
7.What is the process for return or replacement of LMR38020FDDAR?
All LMR38020FDDAR units undergo pre-shipment inspection (PSI). If there is an issue with LMR38020FDDAR, 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 LMR38020FDDAR part is unused and in its original packaging.
Return procedure for LMR38020FDDAR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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