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Texas Instruments LMS3655MMRNLR
- Part No.:
- LMS3655MMRNLR
- Manufacturer:
- Texas Instruments
- Package:
- 22-PowerVFQFN
- Datasheet:
-
LMS3655MMRNLR.pdf
- Description:
- IC REG BUCK ADJ 5.5A 22VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,657
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Product details
Overview
LMS3655MMRNLR from Texas Instruments is a 5.5-A, 36-V synchronous step-down DC-DC converter with adjustable output (1 V to 20 V), 400-kHz fixed switching frequency, ±1.5% reference voltage tolerance, and integrated compensation. It delivers 96% peak efficiency at 12 V → 5 V conversion and supports noise-sensitive industrial and medical power rails.
For engineers reviewing the LMS3655MMRNLR datasheet, LMS3655MMRNLR pinout, LMS3655MMRNLR application, or LMS3655MMRNLR equivalent, key selection considerations include its 3.5–36-V input range, 5.5-A continuous load capability, pseudo-random spread-spectrum EMI reduction, open-drain RESET with 3-ms release timer, and 4-mm × 5-mm VQFN-HR package with wettable flanks.
Technical Context
The LMS3655MMRNLR employs peak current mode control with frequency foldback architecture to maintain regulation down to 3.5 V input at 3.3 V output, enabling operation near dropout. Its pseudo-random spread spectrum reduces EMI without external filtering, while seamless PWM/PFM transition ensures high light-load efficiency.
It integrates an internal 3.1-V LDO (VCC), bootstrap driver (CBOOT), analog ground separation (AGND/PGND), and BIAS pin for auxiliary biasing. The device features built-in soft start, thermal shutdown, UVLO, and overcurrent protection with 6.7–9.5-A high-side current limit and 6–7.7-A low-side limit.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5 V to 36 V - supports wide industrial input sources including 12 V, 24 V, and 36 V rails with 42-V transient tolerance. |
| Output Current | 5.5 A continuous - sustains full load across –40°C to +125°C ambient without derating in thermally optimized layouts. |
| Switching Frequency | 400 kHz (±10%) - enables compact magnetics and predictable EMI filtering; synchronizable from 250–500 kHz via SYNC pin. |
| Efficiency | 96% peak at 12 V → 5 V - minimizes thermal stress and improves system-level power density in space-constrained designs. |
| Quiescent Current | 32 µA at 3.3 VOUT, no load - extends battery life in always-on or low-power standby applications. |
| Reference Voltage | 1.000 V ±1.5% - ensures tight output regulation accuracy across temperature and line/load variations. |
| Duty Cycle Max | 98% - enables ultra-low dropout operation (e.g., 3.5 V IN → 3.3 V OUT) without external boost circuitry. |
Pinout & Package
Package: 22-pin VQFN-HR (RNL), 4.00 mm × 5.00 mm, 0.5-mm pitch, wettable flanks for optical solder inspection.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (PVIN1, PVIN2) | Power input supply | Dual high-current input pins requiring direct connection to bulk capacitors and shared PCB copper pour with PGND. |
| SW | Switch node | Connects to power inductor; high dv/dt node requiring minimized trace area and proximity to PGND for EMI control. |
| CBOOT | Bootstrap capacitor terminal | Drives high-side MOSFET gate; requires 470-nF ceramic capacitor between CBOOT and SW for reliable bootstrapping. |
| FB | Feedback input | Monitors output voltage divider; high-impedance node sensitive to noise-must be routed away from SW and PGND loops. |
| EN | Enable control | Logic-level input (1.7–2.0 V threshold); must not float-pull down via resistor if unused to ensure safe shutdown. |
| RESET | Open-drain fault flag | Asserts low during EN=low or VOUT out-of-tolerance; requires external pullup resistor to logic rail (e.g., VOUT or VCC). |
| BIAS | Auxiliary bias supply | Improves efficiency at low VIN by powering internal circuits from VOUT; must be grounded or externally powered above 15 V output. |
| SYNC | Frequency synchronization | Accepts 250–500 kHz external clock; rising-edge triggered-enables deterministic EMI alignment in multi-rail systems. |
| FPWM | Forced PWM mode select | High = fixed-frequency operation; low = automatic light-load PFM-prevents audible noise and improves light-load efficiency. |
| AGND / PGND | Analog & power ground | Separate ground pins require star-point connection on PCB to minimize noise coupling into feedback path. |
Key Features
| Feature | Design Value |
|---|---|
| Pseudo-random spread spectrum | Reduces peak EMI amplitude by >10 dB across 150 kHz–1 GHz without adding filter components or layout complexity. |
| Integrated compensation | Eliminates external Type-II/III compensation network-reduces BOM count and design iteration time for stable loop response. |
| RESET with 3-ms release timer | Provides glitch-filtered, delay-stabilized power-good signal-replaces discrete supervisor IC and saves board space in safety-critical systems. |
| Wettable-flank VQFN package | Enables automated optical inspection (AOI) of solder joints without X-ray-improves manufacturing yield and field reliability assurance. |
| Low dropout operation | Maintains regulation with only 0.35 V differential at 3.5-A load-supports legacy 3.3-V systems powered from marginal 3.6-V supplies. |
Applications
| Industrial PLC Power Supply | Noise-Sensitive Medical Imaging |
|---|---|
Use Scenario: Distributed I/O modules in programmable logic controllers requiring clean, regulated 5 V or 12 V from 24 V factory bus. IC Role / Device Role / Timing Role: Primary buck regulator delivering isolated, low-noise power to microcontrollers, ADCs, and communication interfaces. Use Value: Spread-spectrum operation and minimized switch-node ringing meet CISPR-22 Class B EMI limits without added ferrites or shielding. | Use Scenario: Front-end power for ultrasound transducer arrays and MRI sensor electronics where switching noise corrupts analog signals. IC Role / Device Role / Timing Role: High-efficiency, low-EMI DC-DC stage converting 12 V or 24 V to precision 3.3 V or 5 V analog rails. Use Value: 96% peak efficiency and <32 µA quiescent current reduce self-heating and thermal drift in sealed medical enclosures. |
| Telecom Base Station RF Module | Automotive ADAS Camera Power |
Use Scenario: Point-of-load conversion for FPGAs and RF transceivers in 5G small cells operating from 48 V intermediate bus. IC Role / Device Role / Timing Role: Synchronous buck converter with SYNC input synchronized to system clock to avoid beat frequencies in RF bands. Use Value: External frequency synchronization eliminates heterodyne interference in adjacent 2.4 GHz/5 GHz Wi-Fi and cellular bands. | Use Scenario: Compact camera module in advanced driver-assistance systems requiring robust 3.3 V power from automotive 12 V battery with cold-crank support. IC Role / Device Role / Timing Role: Wide-input buck regulator supporting 3.5 V minimum start-up and 42 V transient tolerance during load dump. Use Value: 3.5 V minimum input and integrated UVLO with hysteresis ensure reliable operation during engine cranking (5–6 V battery dips). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM61480RQR | 8-A rating, 2.5–36 V input, 2.1-MHz switching, no spread spectrum, smaller 3-mm × 4-mm QFN | Better suited for high-density, high-frequency designs where size and speed outweigh EMI concerns | Select LM61480RQR when board space is critical and EMI filtering is handled at system level. |
| TPS54560BQDDARQ1 | AEC-Q100 qualified, 3.5–60 V input, 5-A, 100–2500 kHz adjustable frequency, no integrated spread spectrum | Designed for automotive under-hood environments with extended temperature and qualification requirements | Choose TPS54560BQDDARQ1 only for automotive production programs requiring AEC-Q100 Grade 1 compliance. |
Compared with LM61480RQR and TPS54560BQDDARQ1, the LMS3655MMRNLR uniquely combines spread-spectrum EMI reduction, wettable-flank inspection capability, and 3.5-V minimum input in a 4-mm × 5-mm footprint-making it optimal for industrial and medical applications where noise, manufacturability, and low-input operation are jointly prioritized.
Availability
LMS3655MMRNLR is available at Aetrix Electronics and suitable for industrial PLCs, medical imaging subsystems, telecom RF modules, and automotive ADAS camera power supplies requiring stable component supply and long-term production continuity.
Supply support for LMS3655MMRNLR 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 company headquartered in Dallas, Texas, designing and manufacturing analog and embedded processing chips for industrial, automotive, and communications markets.
The LMS3655MMRNLR belongs to TI's high-performance industrial DC-DC regulator family, engineered specifically for noise-sensitive, wide-input, high-reliability applications demanding low EMI, high efficiency, and robust thermal performance.
FAQ
What is the minimum input voltage required for the LMS3655MMRNLR to regulate a 3.3-V output at full 5.5-A load?
The LMS3655MMRNLR requires a minimum input voltage of 3.8 V to maintain full 5.5-A output current while regulating a 3.3-V output within ±2.25% accuracy after startup. This value accounts for dropout voltage, inductor DCR, and internal losses under worst-case thermal conditions.
Does the LMS3655MMRNLR support external frequency synchronization, and what is the valid SYNC input range?
Yes, the LMS3655MMRNLR supports external frequency synchronization via the SYNC pin. The valid input frequency range is 250 kHz to 500 kHz, with rising-edge triggering. The device maintains lock across this range and tolerates duty cycles from 25% to 75%.
How does the RESET output of the LMS3655MMRNLR behave when the EN pin is pulled low?
When EN is pulled low, the LMS3655MMRNLR disables regulation and forces the RESET pin low regardless of output voltage status. This behavior provides unambiguous system-level fault indication and eliminates need for external enable coordination logic.
What is the purpose of the BIAS pin on the LMS3655MMRNLR, and when must it be connected?
The BIAS pin powers internal circuitry from the output rail to improve efficiency at low input voltages. It must be connected to VOUT for outputs ≤15 V. For outputs >15 V, BIAS must be grounded or supplied externally to avoid exceeding its 16-V absolute maximum rating.
Can the LMS3655MMRNLR operate in forced PWM mode, and how is it enabled?
Yes, the LMS3655MMRNLR supports forced PWM mode to eliminate variable-frequency operation and associated audible noise. It is enabled by driving the FPWM pin high (≥1.5 V); pulling FPWM low selects automatic light-load PFM mode with diode emulation.
LMS3655MMRNLR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 22-PowerVFQFN
- 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):
- 3.5V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 1V
- Voltage - Output (Max):
- 15V
- Current - Output:
- 5.5A
- Frequency - Switching:
- 250kHz ~ 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 22-VQFN-HR (5x4)
LMS3655MMRNLR FAQ
1.How can I place an order for LMS3655MMRNLR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMS3655MMRNLR 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 LMS3655MMRNLR reliable?
The price and inventory of LMS3655MMRNLR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMS3655MMRNLR is usually 5 days.
3.What payment methods are accepted for LMS3655MMRNLR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMS3655MMRNLR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMS3655MMRNLR?
LMS3655MMRNLR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMS3655MMRNLR 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 LMS3655MMRNLR?
For technical support, including LMS3655MMRNLR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMS3655MMRNLR requirements.
6.How does Aetrix verify that LMS3655MMRNLR is sourced from the original manufacturer or authorized distributors?
All LMS3655MMRNLR 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 LMS3655MMRNLR meets industry standards.
7.What is the process for return or replacement of LMS3655MMRNLR?
All LMS3655MMRNLR units undergo pre-shipment inspection (PSI). If there is an issue with LMS3655MMRNLR, 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 LMS3655MMRNLR part is unused and in its original packaging.
Return procedure for LMS3655MMRNLR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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