LM536353QRNLTQ1 - 3.5A 36V Sync Step-Down DC-DC | TI Automotive
MPN: LM536353QRNLTQ1 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.3 | $4.30 |
| 10 | $3.87 | $38.70 |
| 100 | $3.45 | $345.00 |
| 500 | $3.1 | $1,550.00 |
| 1,000 | $2.79 | $2,790.00 |
LM536353QRNLTQ1 Overview
A synchronous buck (step-down) DC-DC converter is a switched-mode power supply topology that reduces a higher DC input voltage to a lower, well-regulated DC output voltage by rapidly switching an inductor-capacitor energy-transfer network. Within the broader hierarchy, the LM536353QRNLTQ1 belongs to: synchronous buck regulator -> step-down (buck) converter -> switched-mode DC-DC converter -> power management IC -> semiconductor. Synchronous designs replace the conventional Schottky rectifier with a low-side MOSFET, raising efficiency at moderate-to-high load currents, reducing conduction losses, and supporting tighter thermal budgets in compact automotive modules.
Key features include a 3.5A continuous output current rating, a wide 3.5V to 36V (42V transient) input operating range that tolerates automotive load-dump events, 2.1 MHz fixed-frequency operation, internal high-/low-side synchronous MOSFETs, and integrated bootstrap, compensation, and soft-start circuitry. The fixed 3.3V output version (suffix "33") requires no external resistor divider, simplifying BOM and reducing PCB area. AEC-Q100 Grade 1 (TJ = -40C to +125C) qualification, plus TI's automotive-grade reliability flow, makes the part directly suitable for cabin electronics, infotainment head units, ADAS sensors, and body-control modules.
Typical applications include automotive infotainment systems, ADAS sensor power rails (camera, radar, lidar front-end), body-control modules (BCM), instrument clusters, USB charging ports (Type-A/C), and always-on battery-powered subsystems. The 2.1 MHz switching frequency falls above the AM broadcast band, easing CE/RE EMI compliance for OEM vehicle platforms.
When designing with the LM536353QRNLTQ1, place the input bypass ceramic (typically 10uF X7R) directly across PVIN and PGND to suppress switching spikes, and follow the datasheet's recommended copper-pour thermal layout. The exposed thermal pad must be soldered to a continuous ground plane to keep junction temperature within the AEC-Q100 envelope under worst-case load-dump conditions.
This page synthesizes distributor pricing, verified drop-in alternatives within the LM53635-Q1 family, and practical layout/design notes not collected in a single location in the manufacturer datasheet.
Drop-in alternatives for LM536353QRNLTQ1 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
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LM536353QRNLTQ1 Maximum Ratings & Electrical Characteristics
| Topology | Synchronous Step-Down (Buck) |
| Output Voltage | 3.3 V (fixed) |
| Output Current | 3.5 A |
| Input Voltage Range | 3.5 V to 36 V (42 V transient) |
| Switching Frequency | 2.1 MHz (fixed) |
| Number of Outputs | 1 |
| Number of Pins | 2 |
| Package | VQFN-HR (RNL) 22-pin |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -40C to +125C (junction, automotive Grade 1) |
| Automotive Qualification | AEC-Q100 Grade 1 |
| MSL Level | 2 (per JEDEC J-STD-020) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| Internal MOSFETs | Yes (high-side + low-side synchronous) |
| Soft-Start | Internal |
| Output Type | Fixed 3.3 V |
LM536353QRNLTQ1 Pin Configuration
| Pin 1 | PGND — Power ground return for internal low-side FET |
| Pin 2 | SW — Switch node - connect to output inductor |
| Pin 3 | SW — Switch node (continued) - connect to output inductor |
| Pin 4 | SW — Switch node (continued) - connect to output inductor |
| Pin 5 | PGND — Power ground return |
| Pin 6 | BST — Bootstrap supply for high-side gate driver |
| Pin 7 | VIN — Analog input supply |
| Pin 8 | PVIN — Power input supply |
| Pin 9 | PVIN — Power input supply (continued) |
| Pin 10 | EN — Enable input (active high) |
| Pin 11 | PGOOD — Power-good open-drain indicator |
| Pin 12 | RT/SS — Frequency / soft-start setting |
| Pin 13 | COMP — Loop compensation node |
| Pin 14 | FB — Feedback / fixed VOUT sense |
| Pin 15 | AGND — Analog ground |
| Pin 16 | NC — Not connected (per datasheet) |
| Pin 17 | NC — Not connected (per datasheet) |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | NC — Not connected (per datasheet) |
| Pin 21 | NC — Not connected (per datasheet) |
| Pin 22 | EP — Exposed thermal pad - connect to ground |
Typical Applications
LM536353QRNLTQ1 is suitable for 6 applications: Automotive Infotainment Power Rail, ADAS Camera and Sensor Front-End, Body Control Module (BCM) Loads, USB Type-A / Type-C Charging Port, Instrument Cluster Power Supply, Industrial 24 V PLC Power Bus.
Automotive Infotainment Power Rail
The LM536353QRNLTQ1 is well-matched to 12 V automotive infotainment head units because it accepts the full 3.5 V-36 V (42 V transient) input range, including cold-crank and load-dump events, and delivers a clean fixed 3.3 V rail at 3.5 A for SoC, memory, and display backlight subsystems. Its 2.1 MHz switching frequency sits above the AM broadcast band, simplifying conducted/radiated EMI filtering and helping the platform meet CISPR 25 Class 5 limits. AEC-Q100 Grade 1 qualification ensures reliability across cabin temperature extremes, while the integrated synchronous MOSFETs eliminate the external FET bridge, reducing BOM cost and PCB area in the head-unit chassis.
Recommended
ADAS Camera and Sensor Front-End
The LM536353QRNLTQ1 powers ADAS camera, radar, and lidar front-end modules by providing a low-noise 3.3 V / 3.5 A rail directly from the 12 V automotive battery bus. The 2.1 MHz switching frequency and internal synchronous FETs minimize output ripple, which is critical for CMOS image sensor analog rails and SERDES supply pins where supply noise couples into pixel data. AEC-Q100 Grade 1 qualification plus the -40C to +125C junction range support under-chassis and behind-grille sensor placement. The compact 22-pin VQFN-HR (RNL) package fits within space-constrained camera-module PCBs while the exposed pad keeps junction temperature well below limits at continuous 3.5 A load.
Recommended
Body Control Module (BCM) Loads
Body control modules aggregate lighting, door, mirror, and HVAC loads and benefit from the LM536353QRNLTQ1's wide VIN tolerance and 3.5 A output to feed multiple downstream LDOs and relays. The synchronous buck topology achieves high efficiency at moderate loads, easing thermal management inside sealed BCM enclosures, while fixed 2.1 MHz switching supports predictable EMI signatures for module-level CISPR 25 testing. AEC-Q100 Grade 1 qualification plus TI's automotive PPAP documentation let Tier-1 BCM suppliers reference this part directly in their design libraries with confidence.
Recommended
USB Type-A / Type-C Charging Port
The LM536353QRNLTQ1 is a strong primary rail for automotive USB charging ports because its 3.5 V-36 V input directly accepts 12 V battery feeds and delivers 3.3 V / 3.5 A to a downstream USB Type-C controller and VBUS switch. Synchronous rectification keeps efficiency above 90 percent at typical 1.5 A-2.4 A charging loads, reducing connector- and cable-heating risks. AEC-Q100 Grade 1 qualification lets the design satisfy OEM reliability requirements for in-cabin USB ports, while the 22-pin VQFN-HR (RNL) package enables single-sided PCB assembly in tight connector-module enclosures.
Recommended
Instrument Cluster Power Supply
Instrument clusters require a clean, regulated 3.3 V rail for display drivers, MCUs, and CAN transceivers, all of which the LM536353QRNLTQ1 provides at 3.5 A continuous. The 2.1 MHz fixed switching frequency avoids interference with AM radio reception, which is critical in clusters that share wiring harnesses with audio head units. AEC-Q100 Grade 1 reliability supports the harsh thermal environment behind the steering wheel, and the exposed thermal pad maintains low junction temperatures even under sustained cold-crank events at -40C ambient.
Recommended
Industrial 24 V PLC Power Bus
Although AEC-Q100 qualified, the LM536353QRNLTQ1 also serves industrial 24 V PLC and factory-automation backplanes thanks to its 3.5 V-36 V input range and 3.5 A / 3.3 V output. Synchronous buck operation and 2.1 MHz switching support compact, efficient point-of-load design on backplane cards where board height is constrained. The 22-pin VQFN-HR package plus exposed thermal pad handle industrial ambient profiles, while the integrated MOSFETs minimize external component count, a benefit when designing for long-life industrial systems where reliability and parts count directly impact MTBF.
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Recommended Products Summary
Engineering reference data for LM536353QRNLTQ1 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM536353QRNLRQ1 | LM53635NQURNLRQ1 | LM536253QRNLRQ1 | LM536253QRNLTQ1 | LM53635NQURNLTQ1 |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | VQFN-HR (RNL) 22-pin | VQFN-HR (RNL) 22-pin - same | VQFN-HR (RNL) 22-pin - same | VQFN-HR (RNL) 22-pin - same | VQFN-HR (RNL) 22-pin - same | VQFN-HR (RNL) 22-pin - same |
| Output Current | 3.5 A | 3.5 A | 3.5 A | 2.5 A | 2.5 A | 3.5 A |
| Output Voltage | 3.3 V (fixed) | 3.3 V (fixed) | 1.0 V to 28 V (adjustable) | 3.3 V (fixed) | 3.3 V (fixed) | 1.0 V to 28 V (adjustable) |
| Switching Frequency | 2.1 MHz | 2.1 MHz | 2.1 MHz | 2.1 MHz | 2.1 MHz | 2.1 MHz |
| Input Voltage Range | 3.5 V to 36 V | 3.5 V to 36 V | 3.5 V to 36 V | 3.5 V to 36 V | 3.5 V to 36 V | 3.5 V to 36 V |
| AEC-Q100 Grade | Grade 1 | Grade 1 | Grade 1 | Grade 1 | Grade 1 | Grade 1 |
Key Differentiators
- Higher 3.5 A output vs LM25125-Q2 in same footprint (vs LM536253QRNLRQ1)
- Fixed 3.3 V output eliminates resistor divider (vs LM53635NQURNLRQ1)
- AEC-Q100 Grade 1 qualified for harsh automotive environments (vs LM536353QRNLRQ1)
Design Notes
Place the PVIN high-frequency bypass capacitor (2 x 4.7 uF X7R 50 V 0805 minimum) directly across PVIN and PGND with traces no longer than 2 mm to suppress switching spikes. Use a continuous bottom-side ground plane stitched with multiple vias around the PGND pins and exposed thermal pad; the VQFN-HR EP must be soldered to a copper area of at least 50 mm^2 to achieve the datasheet thermal resistance. Place BST capacitor within 1 mm of the BST-SW loop to avoid high-side gate-drive ringing at 2.1 MHz.
Estimated: At VIN = 12 V, VOUT = 3.3 V, and 3.5 A continuous load, the synchronous buck dissipates approximately (12 - 3.3) V * 3.5 A = 0.6 W assuming ideal conversion, plus conduction/switching losses. With datasheet theta_JA 23 C/W on a JEDEC 4-layer board, junction temperature rise is roughly 14 C above ambient. Verify with actual PCB copper; for 4-layer designs with reduced copper, supplement with thermal vias under the EP and consider LM536253Q2 series (2.5 A) if thermals are tight.
Do not connect AGNC/FP/BST/EN traces near the SW node or any high-dV/dt loop; the SW node swings 36 V at 2.1 MHz and couples noise into sensitive analog traces. Avoid running feedback traces parallel to SW or inductor traces. The fixed 3.3 V output variant does not require external resistor dividers, but the FB pin must be tied to the output sense point at the load, not at the inductor, to avoid load-regulation errors at high di/dt.
At 2.1 MHz the fundamental and harmonics fall above the AM broadcast band, simplifying CISPR 25 Class 5 conducted/radiated EMI compliance for automotive 12 V rails. Place an input Pi-filter (1 uF X7R + common-mode choke + 10 uF electrolytic) immediately at the harness entry to attenuate differential-mode switching ripple; spread-spectrum frequency modulation is not present on this family, so choose a switching-frequency offset that avoids harmonics coupling into adjacent AM-band antenna harnesses.
Compliance Information
AEC-Q100 Grade 1 qualified per TI LM53635-Q1 family datasheet. RoHS compliant and lead-free surfaced. Halogen-free status not confirmed in provided data.
