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Texas Instruments LM53635LQRNLTQ1
- Part No.:
- LM53635LQRNLTQ1
- Manufacturer:
- Texas Instruments
- Package:
- 22-PowerVFQFN
- Datasheet:
-
LM53635LQRNLTQ1.pdf
- Description:
- IC REG BUCK 5V 3.5A 22VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:705
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Product details
Overview
LM53635LQRNLTQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous buck DC-DC converter delivering 3.5-A output at 5 V fixed voltage, operating from 3.9 V to 36 V input with 2.1-MHz switching frequency, ±1% output voltage tolerance (–40°C to +125°C), and 15-µA quiescent current - used in automotive head units for stable 5-V rail generation under cold-crank conditions.
For engineers reviewing the LM53635LQRNLTQ1 datasheet, LM53635LQRNLTQ1 pinout, LM53635LQRNLTQ1 application, or LM53635LQRNLTQ1 equivalent, this page delivers verified technical context, validated pin functions, confirmed automotive-grade thermal and EMI performance, and real-world selection guidance for telematics and instrumentation cluster power design.
Technical Context
The LM53635LQRNLTQ1 employs peak-current-mode control with adaptive frequency spreading to maintain regulation down to 300-mV dropout at 3.5 A while sustaining 2.1-MHz operation across wide VIN/VOUT ratios - enabling 18 V → 3.3 V conversion without frequency foldback. Its HotRod QFN package with wettable flanks minimizes switch-node ringing and reduces radiated EMI via partial magnetic field cancellation.
It integrates a 3.1-V internal LDO (VCC), open-drain RESET with 3-ms release timer and built-in glitch filtering, FPWM mode control, external SYNC input (1.9–2.3 MHz), and dual PGND banks for optimized high-current return path separation - all qualified for –40°C to +150°C junction temperature operation per AEC-Q100.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3.5 A continuous - supports automotive infotainment SoCs and display drivers without derating at 105°C ambient. |
| Input Voltage Range | 3.9 V to 36 V - handles automotive cold-crank (down to 3.55 V) and load-dump transients up to 42 V/500 ms. |
| Switching Frequency | 2.1 MHz nominal - enables compact 2.2-µH inductors and avoids AM-band interference; supports external sync. |
| Output Voltage | Fixed 5.0 V ±1% - eliminates external feedback divider, reducing BOM count and no-load power loss. |
| Quiescent Current | 15 µA typical at 3.3-V output (13.5-V IN) - sustains battery-powered standby operation for >1 year in telematics modules. |
| Dropout Voltage | 0.6 V at 3.5 A, 105°C TA - maintains regulation during low-input transients without entering uncontrolled dropout. |
| RESET Function | Open-drain output with 3-ms release timer and 12–45 µs glitch filter - replaces discrete supervisor IC in safety-critical clusters. |
Pinout & Package
LM53635LQRNLTQ1 uses a 5.0 mm × 4.0 mm VQFN-HR (RNL) package with 22 pins and wettable flanks for automated optical solder inspection. Thermal resistance: RθJA = 29.4°C/W, RθJC(bot) = 2.4°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 1) | Internal 3.1-V LDO output | Supplies internal control circuitry; requires 4.7-µF capacitor to AGND for stability and noise rejection. |
| CBOOT (Pin 2) | Bootstrap capacitor node | Connects 470-nF ceramic capacitor to SW; enables high-side MOSFET gate drive above VIN. |
| SYNC (Pin 3) | External clock input | Accepts 1.9–2.3 MHz system clock (rising-edge triggered); synchronizes switching to reduce beat frequencies. |
| PVIN1/PVIN2 (Pins 4,14) | Main power input terminals | Dual high-current VIN paths; must be shorted on PCB to minimize loop inductance and EMI. |
| SW (Pin 9) | Switch node | Connects directly to power inductor; critical for EMI layout - minimized trace area and tight coupling to PGND. |
| PGND1/PGND2 (Pins 5–8,10–13) | Power ground banks | Eight dedicated low-side MOSFET return paths; must be tied together and connected to AGND at single point. |
| FPWM (Pin 16) | Forced PWM mode control | High = fixed 2.1-MHz operation; low = automatic light-load diode emulation for ultra-low IQ. |
| EN (Pin 18) | Enable input | Active-high logic; threshold 1.7–2.0 V; hysteresis 0.45–0.55 V prevents chatter during slow-rising VIN. |
| RESET (Pin 19) | Open-drain fault flag | Asserts low on UVLO, thermal shutdown, or EN deactivation; includes internal 3-ms release timer and 12–45 µs filter. |
| FB (Pin 21) | Feedback reference input | Internally tied to 5-V regulation; not connected externally for fixed-output version - simplifies layout and saves space. |
| BIAS (Pin 22) | Auxiliary bias supply input | Connected to output rail; improves efficiency by powering internal circuits from regulated VOUT instead of VIN. |
Key Features
| Feature | Design Value |
|---|---|
| Automotive qualification | AEC-Q100 Grade 1 (–40°C to +125°C ambient), HBM ±2.5 kV, CDM ±1 kV - certified for front-end electronics in passenger vehicles. |
| Low EMI architecture | HotRod QFN with wettable flanks and optimized internal power loop reduces switch-node ringing and radiated emissions by >10 dB vs standard QFN. |
| Spread-spectrum operation | ±3% frequency dithering centered at 2.1 MHz - lowers peak EMI amplitude without affecting regulation or transient response. |
| Built-in protection suite | Thermal shutdown (155–175°C), cycle-by-cycle current limit (4.5–7.5 A HS), UVLO (3.25–3.55 V), and hiccup-mode short-circuit recovery. |
| Integrated reset generator | True power-good signal with 3-ms release delay and programmable glitch filter - eliminates need for external supervisor IC in ASIL-B systems. |
Applications
| Telematics Control Unit | Automotive Head Unit |
|---|---|
Use Scenario: Powers LTE modem, GNSS receiver, and MCU in vehicle connectivity module with 12-V battery input subject to cold-crank dips. IC Role / Device Role / Timing Role: Primary 5-V power rail regulator with fast transient response and ultra-low IQ for always-on wake-up capability. Use Value: 15-µA quiescent current extends battery backup time; 3.55-V minimum start-up ensures operation during engine cranking. |
Use Scenario: Supplies audio DSP, touchscreen controller, and display interface in infotainment head unit with stringent EMI limits. IC Role / Device Role / Timing Role: High-efficiency 5-V buck converter with spread-spectrum and low-noise HotRod packaging to meet CISPR-25 Class 5 radiated emissions. Use Value: 2.1-MHz switching avoids AM band; integrated RESET replaces discrete supervisor, saving 3 mm² PCB area. |
| Instrument Cluster Display | ADAS Camera Power Module |
Use Scenario: Generates clean 5-V rail for TFT-LCD driver and microcontroller in digital instrument cluster with wide ambient temperature range. IC Role / Device Role / Timing Role: Automotive-grade DC-DC with ±1% output accuracy and 150°C max junction rating for under-hood proximity. Use Value: 0.6-V dropout at 3.5 A ensures uninterrupted operation during 8-V battery dips; wettable flanks enable AOI verification. |
Use Scenario: Powers image sensor and ISP in rear-view or surround-view camera with high reliability and low EMI near RF antennas. IC Role / Device Role / Timing Role: Compact 5-V regulator with external SYNC to align switching edges with camera frame timing and avoid rolling band artifacts. Use Value: SYNC input allows deterministic noise placement; 36-V input withstands load dump without external TVS clamping. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM53635NQRNLTQ1 | 3.3-V fixed output; identical 3.5-A rating, package, and features except output voltage and spread-spectrum enable. | Used where 3.3-V rail required for MCU core or FPGA I/O; not interchangeable without board-level changes. | Select LM53635NQRNLTQ1 only when 3.3-V output is needed - same footprint but different FB network and BIAS connection. |
| LM61460QQRNJRTQ1 | 3.6-A, 6-V max output, 2.1-MHz, smaller 3.5-mm × 3.5-mm QFN; lower IQ (13 µA), higher efficiency at light loads. | Better suited for space-constrained ADAS ECUs; lacks integrated RESET and SYNC input - requires external supervision. | Choose LM61460QQRNJRTQ1 for size-sensitive designs needing higher efficiency below 100 mA; accept added component count for RESET. |
Compared with LM53635NQRNLTQ1, LM53635LQRNLTQ1 provides 5-V output with identical automotive robustness but no spread-spectrum; versus LM61460QQRNJRTQ1, it trades smaller size and lower IQ for integrated RESET and SYNC - critical for cost-sensitive head units.
Availability
LM53635LQRNLTQ1 is available at Aetrix Electronics and suitable for automotive telematics, head unit, and instrumentation cluster applications requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.
Supply support for LM53635LQRNLTQ1 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 and embedded processing technologies, with over 50 years of automotive power management innovation.
The LM53635-Q1 product line delivers high-current, high-frequency synchronous buck regulators optimized for automotive infotainment, ADAS, and body electronics - designed to replace multi-chip solutions with single-package AEC-Q100-compliant power stages.
FAQ
What is the minimum input voltage required for LM53635LQRNLTQ1 to start regulation?
The LM53635LQRNLTQ1 has a rising UVLO threshold of 3.25 V to 3.55 V, with hysteresis of 0.28–0.4 V. It achieves full functionality at 3.5 V input for 1.5-A load and 3.9 V for 3.5-A load after startup. The device can regulate a 5-V output from as low as 3.55 V input - critical for cold-crank operation in automotive systems. This behavior is confirmed in Section 7.3 and 7.6 of the LM53635-Q1 datasheet.
Does LM53635LQRNLTQ1 require an external feedback resistor divider?
No. LM53635LQRNLTQ1 is a fixed 5-V output variant - the feedback reference is internally set to 5.0 V with ±1% tolerance over –40°C to +125°C junction temperature. Pin 21 (FB) is internally connected and must remain unconnected on the PCB. This eliminates external resistors, reduces BOM cost, and removes associated tolerance and temperature drift errors - a key advantage over adjustable versions like LM53635AQRNLTQ1.
What is the purpose of the BIAS pin on LM53635LQRNLTQ1?
The BIAS pin (Pin 22) on LM53635LQRNLTQ1 connects to the regulated 5-V output rail to power internal circuitry, improving conversion efficiency by reducing VIN current draw. When BIAS is supplied from VOUT, the device achieves lower quiescent current and higher light-load efficiency. For LM53635LQRNLTQ1, BIAS must be tied directly to the 5-V output node - no external components are required, and operation without BIAS connection degrades performance.
How does the RESET output of LM53635LQRNLTQ1 behave during startup and fault conditions?
The RESET output of LM53635LQRNLTQ1 is an open-drain flag that goes low during EN deactivation, input UVLO, thermal shutdown, or output overvoltage. It features a built-in 3-ms release timer after fault clearance and a 12–45 µs glitch filter to reject noise. RESET asserts high only when output is within 94–110% of nominal 5 V and EN is high - providing a true system-ready signal without external timing components.
Can LM53635LQRNLTQ1 synchronize to an external clock, and what are the requirements?
Yes, LM53635LQRNLTQ1 supports external synchronization via Pin 3 (SYNC). It accepts a 1.9–2.3 MHz square wave with 25–75% duty cycle, triggered on the rising edge. The SYNC input has VIH ≥ 1.5 V and VIL ≤ 0.4 V, with hysteresis of 0.15–1 V. Synchronization enables deterministic EMI placement in multi-rail systems and eliminates beat frequencies - essential for automotive EMC compliance in head units and clusters.
LM53635LQRNLTQ1 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:
- 3.5A
- Frequency - Switching:
- 2.1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 22-VQFN-HR (5x4)
LM53635LQRNLTQ1 FAQ
1.How can I place an order for LM53635LQRNLTQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM53635LQRNLTQ1 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 LM53635LQRNLTQ1 reliable?
The price and inventory of LM53635LQRNLTQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM53635LQRNLTQ1 is usually 5 days.
3.What payment methods are accepted for LM53635LQRNLTQ1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM53635LQRNLTQ1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM53635LQRNLTQ1?
LM53635LQRNLTQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM53635LQRNLTQ1 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 LM53635LQRNLTQ1?
For technical support, including LM53635LQRNLTQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM53635LQRNLTQ1 requirements.
6.How does Aetrix verify that LM53635LQRNLTQ1 is sourced from the original manufacturer or authorized distributors?
All LM53635LQRNLTQ1 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 LM53635LQRNLTQ1 meets industry standards.
7.What is the process for return or replacement of LM53635LQRNLTQ1?
All LM53635LQRNLTQ1 units undergo pre-shipment inspection (PSI). If there is an issue with LM53635LQRNLTQ1, 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 LM53635LQRNLTQ1 part is unused and in its original packaging.
Return procedure for LM53635LQRNLTQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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