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Texas Instruments LMS3655AMRNLR
- Part No.:
- LMS3655AMRNLR
- Manufacturer:
- Texas Instruments
- Package:
- 22-PowerVFQFN
- Datasheet:
-
LMS3655AMRNLR.pdf
- Description:
- IC REG BUCK ADJ 5.5A 22VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,725
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Product details
Overview
LMS3655AMRNLR from Texas Instruments is a 5.5-A, 36-V synchronous step-down DC-DC converter in a 4-mm × 5-mm VQFN-HR package, delivering adjustable 1-V to 20-V output with 400-kHz fixed switching frequency, ±1.5% reference voltage tolerance, and 96% peak efficiency at 12-V input to 5-V output. It serves as the primary power stage in high-performance industrial and telecom systems requiring robust transient response and low EMI.
For engineers reviewing the LMS3655AMRNLR datasheet, LMS3655AMRNLR pinout, LMS3655AMRNLR application, or LMS3655AMRNLR equivalent, key selection criteria include its 3.5-V minimum operating input (for 3.3-V output), 32-µA quiescent current at no load, integrated RESET with 3-ms release timer, FPWM mode control, and thermal shutdown at 160°C–185°C.
Technical Context
The LMS3655AMRNLR uses peak current mode control with frequency foldback architecture to maintain regulation down to 0.35-V dropout at 3.5-A load and extend operation to 3.5-V input for 3.3-V output. Its pseudo-random spread spectrum reduces EMI while minimizing switch-node ringing via flip-chip packaging and optimized magnetic field cancellation.
It integrates internal compensation, soft-start, current limiting (HS: 6.7–9.5 A, LS: 6–7.7 A), and an open-drain RESET output with built-in 24-µs glitch filter and 2–4-ms activation delay. The BIAS pin enables auxiliary bias regulation, and SYNC supports external clock synchronization from 250 kHz to 500 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 5.5-A continuous load capability ensures stable rail delivery for FPGA core supplies and multi-rail industrial processors. |
| Input Voltage Range | 3.5 V to 36 V (transient tolerant to 42 V) simplifies surge protection design in 24-V industrial bus applications. |
| Switching Frequency | 400 kHz ±10% enables compact 10-µH inductor and low-profile 3×47-µF output capacitor bank. |
| Quiescent Current | 32 µA at 3.3-V output and no load extends battery life in always-on monitoring subsystems. |
| Reference Tolerance | ±1.5% over –40°C to +125°C ambient guarantees tight output accuracy without external trimming. |
| Duty Cycle Max | 98% in dropout enables regulation with only 650-mV VIN–VOUT margin-critical for low-headroom 3.3-V systems. |
| RESET Delay | 3-ms release timer and 24-µs glitch filter eliminate need for external supervisor IC in safety-critical power sequencing. |
Pinout & Package
Package: VQFN-HR (RNL), 22-pin, 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 reduce PCB trace resistance and thermal stress; must be shorted on board. |
| PGND1, PGND2 | Power ground return | Separate low-side MOSFET ground paths minimize switching noise coupling into analog circuitry. |
| SW | Switch node | Connects directly to inductor; layout critical for EMI-flip-chip construction minimizes ring amplitude. |
| FB | Feedback input | Resistive divider sets output voltage; 1-V internal reference enables 1–20-V adjustment range. |
| EN | Enable control | Logic-level input (1.7–2.0 V threshold) with 0.5-V hysteresis prevents erratic startup during brownout. |
| RESET | Open-drain fault flag | Pulls low on EN deactivation or output undervoltage; operates down to 1.5-V input-no external supervisor needed. |
| BIAS | Auxiliary bias supply | Connected to VOUT to improve light-load efficiency and enable full functionality below 6-V output. |
| SYNC | Frequency sync input | Accepts 250–500 kHz external clock to eliminate beat frequencies in multi-regulator systems. |
| FPWM | Mode select | Forces continuous PWM (high) or enables auto PFM (low); eliminates audible noise in standby modes. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated compensation | Eliminates 4–6 external compensation components-reduces BOM count and layout sensitivity. |
| Low EMI switch node | Flip-chip packaging and minimized parasitic inductance cut radiated emissions by >10 dB vs conventional QFN. |
| Automatic light-load mode | Diode emulation reduces RMS inductor current and switching losses below ~200 mA load. |
| Thermal shutdown | 160°C trip with 15°C hysteresis protects against sustained overload without latch-up. |
| Soft-start time | 2.5–5 ms ramp prevents inrush current damage to input capacitors and downstream loads. |
Applications
| Industrial PLC I/O Module | Telecom Remote Radio Unit |
|---|---|
Use Scenario: Powering isolated analog front-ends and digital signal processors in DIN-rail mounted controllers exposed to 40-V transients. IC Role / Device Role / Timing Role: Primary 5.5-A buck regulator delivering 3.3-V/5-V rails with RESET-driven FPGA configuration lockout during brownout. Use Value: 3.5-V minimum input and 42-V transient tolerance eliminate need for upstream TVS clamping; wettable flanks ensure IPC-A-610-compliant reflow inspection. | Use Scenario: Generating stable 12-V bias for GaN PA stages and 3.3-V logic in outdoor 5G small cells with wide ambient temperature swing. IC Role / Device Role / Timing Role: High-efficiency, low-noise DC-DC stage synchronized to system clock via SYNC pin to avoid spectral interference. Use Value: Pseudo-random spread spectrum and minimized switch-node ringing meet EN55022 Class B conducted/radiated limits without added ferrites. |
| Noise-Sensitive Medical Imaging | High-Performance Test Equipment |
Use Scenario: Supplying ultra-low-noise ADC reference and FPGA fabric in portable ultrasound beamformers. IC Role / Device Role / Timing Role: Low-quiescent-current buck converter enabling battery-backed standby with 32-µA IQ_VIN and automatic PFM transition. Use Value: 96% peak efficiency at 12-V→5-V and <1% output voltage drift over –40°C to +125°C ensure consistent SNR across operating conditions. | Use Scenario: Providing precision 1.8-V and 2.5-V rails for high-speed DACs and clock distribution ICs in automated test systems. IC Role / Device Role / Timing Role: Adjustable-output buck with ±1.5% reference tolerance and integrated soft-start for repeatable power-up sequencing. Use Value: Built-in RESET with 3-ms delay replaces discrete supervisor, reducing footprint by 25 mm² and eliminating timing mismatch risks. |
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 | Higher 8-A rating, 2.1-MHz switching, smaller 3-mm × 2-mm QFN; lacks integrated RESET and spread spectrum. | Better suited for space-constrained, high-frequency designs where supervisor IC is already present. | Select LM61480RQR when board area is critical and external reset supervision is acceptable. |
| TPS54560BQDDARQ1 | Automotive-grade (-40°C to +125°C), 60-V max input, 5-A output; no BIAS pin or FPWM mode; lower 92% peak efficiency. | Targeted at automotive infotainment and ADAS power rails requiring AEC-Q100 qualification. | Choose TPS54560BQDDARQ1 only for automotive programs needing qualified components and higher input voltage headroom. |
Compared with LM61480RQR and TPS54560BQDDARQ1, the LMS3655AMRNLR uniquely combines integrated RESET, spread-spectrum EMI reduction, and 3.5-V minimum input operation-making it optimal for industrial and medical systems prioritizing reliability, noise immunity, and component count reduction.
Availability
LMS3655AMRNLR is available at Aetrix Electronics and suitable for industrial PLCs, telecom remote radio units, noise-sensitive medical imaging systems, and high-performance test equipment requiring stable component supply and long-term production continuity.
Supply support for LMS3655AMRNLR 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 over 90 years of innovation in high-reliability electronics.
The LMS3655AMRNLR belongs to TI's high-performance industrial DC-DC regulator product line, engineered for demanding applications requiring wide input range, low EMI, and integrated system-level features like RESET and SYNC.
FAQ
What is the minimum input voltage required for LMS3655AMRNLR to regulate a 3.3-V output?
The LMS3655AMRNLR can regulate a 3.3-V output from as low as 3.5 V input after startup, per the System Characteristics table. This 650-mV dropout capability is enabled by frequency foldback architecture and 98% maximum duty cycle-critical for low-headroom industrial 3.3-V systems. Below 3.5 V, regulation is not guaranteed.
Does LMS3655AMRNLR support external frequency synchronization, and what is the valid range?
Yes, the LMS3655AMRNLR supports external frequency synchronization via the SYNC pin, accepting a clock signal from 250 kHz to 500 kHz. The device triggers on the rising edge and maintains stable operation within this range, allowing precise alignment with system clocks to avoid beat frequencies in multi-rail power architectures.
How does the RESET function of LMS3655AMRNLR behave when the EN pin is pulled low?
When EN is pulled low, the LMS3655AMRNLR forces the open-drain RESET output low regardless of output voltage status-providing unambiguous fault signaling during shutdown. RESET remains functional down to 1.5-V input voltage and includes a 24-µs glitch filter and 2–4-ms activation delay to prevent false triggering during transients.
What is the purpose of the BIAS pin on LMS3655AMRNLR, and how should it be connected?
The BIAS pin on LMS3655AMRNLR supplies auxiliary bias to the internal LDO and improves light-load efficiency. For outputs ≥6 V, connect BIAS to VOUT; for outputs <6 V, grounding BIAS is recommended. Operation above 15 V requires BIAS to be grounded or externally powered-TI specifies a maximum 16-V rating on this pin.
Is LMS3655AMRNLR pin-compatible with other devices in the LMS3655 family, such as LMS3655MMRNLR?
Yes, all LMS3655 variants-including LMS3655AMRNLR and LMS3655MMRNLR-share identical 22-pin VQFN-HR (RNL) packaging and pinout. The only functional difference is spread-spectrum enablement (LMS3655MMRNLR has it; LMS3655AMRNLR does not), making them drop-in replacements except where EMI requirements mandate spread spectrum.
LMS3655AMRNLR 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)
LMS3655AMRNLR FAQ
1.How can I place an order for LMS3655AMRNLR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMS3655AMRNLR 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 LMS3655AMRNLR reliable?
The price and inventory of LMS3655AMRNLR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMS3655AMRNLR is usually 5 days.
3.What payment methods are accepted for LMS3655AMRNLR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMS3655AMRNLR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMS3655AMRNLR?
LMS3655AMRNLR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMS3655AMRNLR 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 LMS3655AMRNLR?
For technical support, including LMS3655AMRNLR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMS3655AMRNLR requirements.
6.How does Aetrix verify that LMS3655AMRNLR is sourced from the original manufacturer or authorized distributors?
All LMS3655AMRNLR 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 LMS3655AMRNLR meets industry standards.
7.What is the process for return or replacement of LMS3655AMRNLR?
All LMS3655AMRNLR units undergo pre-shipment inspection (PSI). If there is an issue with LMS3655AMRNLR, 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 LMS3655AMRNLR part is unused and in its original packaging.
Return procedure for LMS3655AMRNLR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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