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Texas Instruments LMS3655LQRNLTQ1
- Part No.:
- LMS3655LQRNLTQ1
- Manufacturer:
- Texas Instruments
- Package:
- 22-PowerVFQFN
- Datasheet:
-
LMS3655LQRNLTQ1.pdf
- Description:
- IC REG BUCK 5V 5.5A 22VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,080
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Product details
Overview
LMS3655LQRNLTQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous buck converter delivering up to 5.5 A continuous output current, operating from 3.9 V to 36 V input, with fixed 5-V output, 400-kHz switching frequency (±10%), and integrated high- and low-side MOSFETs. It enables compact, high-efficiency power conversion in vehicle USB charging and surround-view ECU applications.
For engineers reviewing the LMS3655LQRNLTQ1 datasheet, LMS3655LQRNLTQ1 pinout, LMS3655LQRNLTQ1 application, or LMS3655LQRNLTQ1 equivalent, key selection considerations include its 5.5-A rated output, 36-V max input with 42-V transient tolerance, ±1.5% reference voltage accuracy, 18-µA quiescent current at 3.3-V output/no load, and automotive-grade thermal performance up to +150°C junction temperature.
Technical Context
The LMS3655LQRNLTQ1 employs peak current mode control with internal compensation and automatic light-load PFM/PWM transition, enabling high efficiency across 10 µA–5.5 A load range. Its flip-chip VQFN package minimizes parasitic inductance, reducing switch-node ringing and conducted EMI without external filters.
It integrates a 3.1-V internal LDO (VCC), bootstrap gate driver (CBOOT), open-drain RESET with 3-ms release timer and built-in glitch filter, and supports external frequency synchronization (250–500 kHz). The BIAS pin enables efficient operation down to 3.5-V input via auxiliary bias regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.9 V to 36 V; supports 42-V/500-ms transients - simplifies front-end surge protection design |
| Output Voltage | Fixed 5 V ±1.5% - ensures stable USB-compliant rail without external feedback resistors |
| Max Output Current | 5.5 A continuous - sustains full load under +125°C ambient with thermally optimized PCB |
| Switching Frequency | 400 kHz ±10% (fixed) - enables use of small 2.2-µH inductors and reduces EMI fundamental energy |
| IQ at VIN | 18 µA typical (3.3-V out, no load) - extends battery runtime in always-on automotive modules |
| Efficiency @ 12 V→5 V | 96% peak - minimizes thermal stress and improves system-level power density |
| Junction Temp Range | –40°C to +150°C - meets AEC-Q100 Grade 1 requirements for engine bay and ADAS ECUs |
Pinout & Package
The LMS3655LQRNLTQ1 is housed in a 22-pin VQFN (RNL) package measuring 4.0 mm × 5.0 mm with wettable flanks for automated optical solder inspection.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VCC) | Internal LDO output | Supplies 3.1 V to control circuitry; requires 4.7-µF ceramic capacitor to AGND |
| 2 (CBOOT) | Bootstrap capacitor node | Drives high-side MOSFET gate; connects to SW via 470-nF capacitor |
| 3 (SYNC) | Frequency sync input | Accepts 250–500 kHz external clock (rising-edge triggered); enables system-wide timing coordination |
| 4,14 (PVIN1, PVIN2) | Main power inputs | Parallel-connected high-current VIN paths; must be shorted on PCB with local bulk capacitance |
| 5,10 (PGND1, PGND2) | Power ground returns | Low-inductance return paths for internal MOSFETs; tied together and connected to AGND |
| 9 (SW) | Switch node | Connects to power inductor; high dv/dt node requiring tight layout and minimal trace area |
| 15 (AVIN) | Analog supply input | Bias source for internal analog circuits; connected directly to PVIN1/PVIN2 |
| 16 (FPWM) | Mode control input | High = forced PWM (no PFM); low = automatic light-load mode; must not float |
| 18 (EN) | Enable input | Active-high logic; 1.7–2.0 V threshold; includes 0.5-V hysteresis and wake-up capability |
| 19 (RESET) | Open-drain fault flag | Asserts low during UVLO, overtemp, or EN deactivation; includes 24-µs glitch filter and 3-ms release delay |
| 20 (AGND) | Analog ground reference | Reference for FB, VREF, and internal error amplifier; star-connected to PGND at single point |
| 21 (FB) | Feedback input | Monitors regulated 5-V output directly (no divider needed); 1-V reference with ±1.5% tolerance |
| 22 (BIAS) | Auxiliary bias input | Enables operation down to 3.5-V input by powering internal regulators from VOUT |
Key Features
| Feature | Design Value |
|---|---|
| Integrated high- and low-side MOSFETs | Reduces BOM count and layout complexity; eliminates external driver and discrete FET selection |
| Automatic light-load PFM mode | Maintains >85% efficiency at 100 µA load - critical for always-on automotive modules |
| Open-drain RESET with internal timing | Replaces external supervisor IC; provides true power-good status with 3-ms release and 24-µs noise immunity |
| Wettable flank VQFN package | Enables AOI-based solder joint inspection without X-ray - improves manufacturing yield and field reliability |
| Spread-spectrum option (L variant) | ±3% frequency modulation reduces peak EMI by >10 dB - eases CISPR 25 Class 5 compliance |
Applications
| Automotive USB Charging | Surround-View System ECU |
|---|---|
Use Scenario: Powering dual-port 5-V/3-A USB Type-C PD sink in center console or rear-seat module. IC Role / Device Role / Timing Role: Primary 12-V-to-5-V step-down regulator with fast load-transient response and low standby IQ. Use Value: Delivers 5.5-A peak current headroom for simultaneous port negotiation while maintaining <1% output droop and 94% efficiency at 3.5-A load. | Use Scenario: Supplying image signal processor (ISP), SerDes, and camera interface logic in 4-camera surround-view domain controller. IC Role / Device Role / Timing Role: Main 5-V rail generator with RESET monitoring for safe boot sequencing and fault reporting. Use Value: Enables single-rail power architecture with integrated reset supervision - eliminates discrete supervisor and saves 22 mm² PCB area. |
| Mechanically Scanning LIDAR | Driver Monitoring System |
Use Scenario: Providing stable 5-V supply to MEMS mirror driver, laser diode bias, and ADC in high-vibration LIDAR head unit. IC Role / Device Role / Timing Role: High-reliability DC/DC converter with 42-V transient tolerance and –40°C to +125°C ambient rating. Use Value: Withstands load-dump events without shutdown; maintains regulation during cold-crank (3.5-V min input with BIAS assist). | Use Scenario: Powering infrared LED array, ToF sensor, and eye-tracking SoC in A-pillar-mounted driver attention monitor. IC Role / Device Role / Timing Role: Low-noise, low-IQ 5-V source supporting always-on sensing with <20-µA sleep current. Use Value: Achieves 18-µA IQ_VIN at no load - extends battery backup duration beyond 72 hours during vehicle sleep mode. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM61480QRNXTQ1 | 6-A rated, 2.5-V to 36-V input, 400-kHz fixed freq, but no spread spectrum or BIAS pin | Lacks input undervoltage foldback below 3.5 V and integrated RESET with filtering | Prefer when higher output current margin is required and spread-spectrum EMI reduction is not critical |
| TPS54560QDGQRQ1 | 5.5-A, 3.5-V to 60-V input, adjustable output only, no integrated BIAS or RESET | Requires external feedback network and supervisor IC; larger solution size | Select when wider input range (up to 60 V) is mandatory and board space allows discrete support components |
Compared with LM61480QRNXTQ1 and TPS54560QDGQRQ1, the LMS3655LQRNLTQ1 uniquely combines 5.5-A capability with spread-spectrum EMI reduction, BIAS-assisted ultra-low-input operation, and integrated RESET - making it optimal for space-constrained, EMI-sensitive automotive ADAS modules where BOM count and qualification effort must be minimized.
Availability
LMS3655LQRNLTQ1 is available at Aetrix Electronics and suitable for automotive USB charging, surround-view ECU, and mechanically scanning LIDAR applications requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.
Supply support for LMS3655LQRNLTQ1 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 automotive electronics, with decades of automotive qualification expertise and broad power management portfolio.
The LMS3655-Q1 product line delivers high-current, wide-input synchronous buck converters optimized for AEC-Q100 Grade 1 automotive ADAS, infotainment, and body electronics - emphasizing low EMI, high efficiency at light loads, and simplified system integration.
FAQ
What is the minimum input voltage required for LMS3655LQRNLTQ1 to regulate a stable 5-V output?
The LMS3655LQRNLTQ1 requires a minimum input voltage of 3.9 V for full functionality after startup. However, with the BIAS pin connected to the 5-V output, it can regulate down to 3.5 V input while maintaining 5-V output accuracy - verified per Section 7.7 VIN-MIN specification and enabled by its auxiliary bias regulator architecture.
Does LMS3655LQRNLTQ1 support external frequency synchronization, and what is the valid range?
Yes, the LMS3655LQRNLTQ1 supports external frequency synchronization via the SYNC pin. The valid input frequency range is 250 kHz to 500 kHz, with rising-edge triggering. This allows precise alignment of switching edges across multiple rails in complex automotive systems to reduce beat-frequency EMI.
How does the RESET output of LMS3655LQRNLTQ1 behave during startup and fault conditions?
The LMS3655LQRNLTQ1 RESET output is open-drain and asserts low during EN deactivation, input UVLO, or thermal shutdown. It features a built-in 24-µs glitch filter and a 3-ms release timer after fault clearance. At startup, RESET remains low until output reaches 96% of 5 V and stabilizes, then transitions high after the 3-ms delay - providing clean, debounced power-good signaling.
What thermal performance can be expected from LMS3655LQRNLTQ1 on a standard 4-layer FR4 PCB?
When mounted on a thermally optimized 4-layer FR4 evaluation board (40 mm × 30 mm), the LMS3655LQRNLTQ1 achieves a junction-to-ambient thermal resistance (RθJA) of 29.4°C/W. This enables continuous 5.5-A operation at +125°C ambient with proper copper pour and thermal vias - validated per Section 7.5 Thermal Information data.
Is LMS3655LQRNLTQ1 pin-compatible with other devices in the LMS36x5-Q1 family?
Yes, all LMS36x5-Q1 variants - including LMS3635-Q1 and LMS3655-Q1 - share identical 22-pin VQFN (RNL) pinout and footprint. The LMS3655LQRNLTQ1 is functionally and physically compatible with LMS3635-Q1 designs, allowing direct upgrade to 5.5-A output capability without PCB revision, provided thermal and layout margins support the higher current.
LMS3655LQRNLTQ1 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:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.9V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 5.5A
- Frequency - Switching:
- 250kHz ~ 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 22-VQFN-HR (5x4)
LMS3655LQRNLTQ1 FAQ
1.How can I place an order for LMS3655LQRNLTQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for LMS3655LQRNLTQ1 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 LMS3655LQRNLTQ1 reliable?
The price and inventory of LMS3655LQRNLTQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMS3655LQRNLTQ1 is usually 5 days.
3.What payment methods are accepted for LMS3655LQRNLTQ1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMS3655LQRNLTQ1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMS3655LQRNLTQ1?
LMS3655LQRNLTQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMS3655LQRNLTQ1 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 LMS3655LQRNLTQ1?
For technical support, including LMS3655LQRNLTQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMS3655LQRNLTQ1 requirements.
6.How does Aetrix verify that LMS3655LQRNLTQ1 is sourced from the original manufacturer or authorized distributors?
All LMS3655LQRNLTQ1 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 LMS3655LQRNLTQ1 meets industry standards.
7.What is the process for return or replacement of LMS3655LQRNLTQ1?
All LMS3655LQRNLTQ1 units undergo pre-shipment inspection (PSI). If there is an issue with LMS3655LQRNLTQ1, 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 LMS3655LQRNLTQ1 part is unused and in its original packaging.
Return procedure for LMS3655LQRNLTQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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