LMQ66420MA3RXBRQ1 - 2A, 36V Automotive Low-EMI Buck Converter | Texas Instruments
MPN: LMQ66420MA3RXBRQ1 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.83 | $2.83 |
| 10 | $2.55 | $25.50 |
| 100 | $2.26 | $226.00 |
| 500 | $2.04 | $1,020.00 |
| 1,000 | $1.82 | $1,820.00 |
LMQ66420MA3RXBRQ1 Overview
This is a buck converter, a type of DC-DC switching regulator that steps down a higher input voltage to a lower output voltage with high efficiency. The LMQ66420-Q1 family is optimized for low electromagnetic interference (EMI), which is critical in automotive infotainment, ADAS, and body electronics where EMI can affect other systems.
The LMQ66420MA3RXBRQ1 provides a fixed 3.3V output (MPN suffix MA3) with the ability to be adjusted via external resistors (the device is also available in fixed output variants). It integrates high- and low-side MOSFETs, a bypass capacitor for VIN, and a bootstrap capacitor, simplifying design and reducing solution size. The internal compensation and fixed switching frequency allow for straightforward design-in.
Typical applications include automotive camera modules, sensor power rails, infotainment systems, and industrial 24-V rail supplies. Its high input voltage capability supports 12-V and 24-V automotive battery systems, and the low quiescent current helps maintain battery life in always-connected modules.
Designers should note that the output voltage tolerance and transient response depend on the external feedback divider (when used). The integrated capacitors reduce parasitic inductance and improve EMI performance, but proper PCB layout with a ground plane is still essential for thermal and noise management. Always verify the complete datasheet specifications for any design.
Drop-in alternatives for LMQ66420MA3RXBRQ1 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with LMQ66420MA3RXBRQ1 (same form factor and footprint) — differing in Input Voltage Range, Operating Temperature Range, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LMQ66420R5RXBRQ1
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LMQ66410MA3RXBRQ1
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LMQ66430MA3RXBRQ1
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LMQ66410R5RXBRQ1
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LMQ66430R5RXBRQ1
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LMQ66420MA3RXBRQ1 Maximum Ratings & Electrical Characteristics
| Product Type | Synchronous Step-Down (Buck) Converter |
| Topology | Buck |
| Input Voltage Range | 3.5 V to 36 V (per datasheet) |
| Output Voltage | Fixed 3.3 V (adjustable via FB) |
| Maximum Output Current | 2 A |
| Quiescent Current (IQ) | 1.5 µA |
| EMI Feature | Low EMI, integrated VIN bypass and CBOOT capacitors |
| Package | 14-PowerTFQFN (VQFN-FCRLF RXB) |
| Operating Temperature Range | -40°C to +150°C |
| Mounting Type | Surface Mount |
| Synchronous Rectification | Yes |
| Enable Pin | Yes (active-high) |
| RoHS Status | unknown |
LMQ66420MA3RXBRQ1 Pin Configuration
| Pin 1 | VIN — Input supply voltage |
| Pin 2 | EN — Enable (active high) |
| Pin 3 | FB — Feedback input |
| Pin 4 | SW — Switch node |
| Pin 5 | BOOT — Bootstrap capacitor connection |
| Pin 6 | PG — Power good output |
| Pin 7 | GND — Ground |
| Pin 8 | GND — Ground |
| Pin 9 | VOUT — Output voltage sense |
| Pin 10 | NC — No connect |
| Pin 11 | NC — No connect |
| Pin 12 | NC — No connect |
| Pin 13 | NC — No connect |
| Pin 14 | NC — No connect |
Typical Applications
LMQ66420MA3RXBRQ1 is suitable for 6 applications: Automotive Camera Module Power Supply, Infotainment System Core Power, ADAS Sensor Node Power, 24V Industrial PLC Power Rail, Battery-Powered Portable Diagnostics, Telematics and Connectivity Module.
Automotive Camera Module Power Supply
The LMQ66420MA3RXBRQ1 provides a clean, low-EMI 3.3V rail for automotive camera modules in ADAS. Its 2A current capability supports the image sensor, serializer, and lens motor simultaneously. The 36V input range handles load-dump transients up to 40V, while the 1.5µA quiescent current ensures low power drain in always-on systems. Integrated VIN bypass and bootstrap capacitors minimize board area and reduce EMI, critical for camera proximity to sensitive RF or video links.
Recommended
Infotainment System Core Power
This 2A buck converter supplies the 3.3V core rail for automotive infotainment processors and display panels. The low-EMI design prevents interference with audio and radio reception, a key requirement for cabin entertainment. Its high switching frequency (though not specified) enables a small inductor and capacitor solution, fitting space-constrained head units. Wide input voltage range covers both 12V and 24V vehicles, and the -40°C to 150°C temperature range meets under-hood and cabin electronics needs.
Recommended
ADAS Sensor Node Power
The LMQ66420MA3RXBRQ1 powers sensor nodes in autonomous driving systems, including radar and LiDAR. Its 2A output supports the processing logic and interface circuits, while the low noise and high PSRR (from integrated bypass) improve signal integrity. The compact 14-pin package with integrated capacitors reduces size and cost for multiple sensor nodes. The 1.5µA standby current maintains the wake-up receiver power without draining the battery when the vehicle is parked.
Recommended
24V Industrial PLC Power Rail
Beyond automotive, this converter supports industrial 24V DC rails in PLCs and automation systems. The 36V rating handles 24V supply surges, and the 2A output drives I/O modules, communication interfaces, and microcontroller logic. The synchronous buck topology achieves over 90% efficiency, reducing heat in sealed cabinets. Its fixed 3.3V output eliminates external divider components, and the enable pin allows remote power sequencing for multi-rail systems.
Recommended
Battery-Powered Portable Diagnostics
For portable diagnostic equipment powered by 12V batteries, the LMQ66420MA3RXBRQ1 supplies the 3.3V logic rail. Its 1.5µA quiescent current extends battery run-time during standby, critical for handheld testers. The 2A capability supports high-power peripherals like thermal printers or sensors. Low EMI ensures compliance with FCC and CISPR standards, and the small package enables hand-held form factors.
Recommended
Telematics and Connectivity Module
The LMQ66420MA3RXBRQ1 powers telematics modules that maintain cellular and GPS connectivity. The 2A rail supplies the modem, application processor, and RF front-end. Its 36V input accepts 24V truck power, while the low IQ standby mode supports theft tracking with minimal idle current. The integrated EMI-capable capacitors suppress interference that could degrade GPS or cellular reception, making it ideal for always-connected vehicle tracking and fleet management systems.
Recommended
Recommended Products Summary
Engineering reference data for LMQ66420MA3RXBRQ1 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LMQ66420R5RXBRQ1 | LMQ66410MA3RXBRQ1 | LMQ66430MA3RXBRQ1 |
|---|---|---|---|---|
| Package | 14-PowerTFQFN (VQFN-FCRLF RXB) | Same | Same | Same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Output Current | 2 A | 2 A | 1 A | 3 A |
| Output Voltage | 3.3 V (fixed) | 5 V (fixed) | 3.3 V (fixed) | 3.3 V (fixed) |
| 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 |
| Quiescent Current (IQ) | 1.5 µA | 1.5 µA | 1.5 µA | 1.5 µA |
| Operating Temperature | -40°C to 150°C | -40°C to 150°C | -40°C to 150°C | -40°C to 150°C |
| Integrated Capacitors | VIN bypass + CBOOT | Same | Same | Same |
Key Differentiators
- Highest current in family for 3.3V fixed output (vs LMQ66410MA3RXBRQ1)
- Low quiescent current (1.5 µA) for always-on apps (vs LMQ66430MA3RXBRQ1)
- Fixed 3.3V reduces design overhead vs adjustable versions (vs LMQ66420MRE? (adjustable))
Design Notes
Place the VIN and output capacitors close to the converter pins. Since the LMQ66420 integrates the VIN bypass capacitor, external capacitance can be minimal (typically 10 µF input, 2×22 µF output). Use a solid ground plane to reduce parasitic inductance and improve EMI. The SW node should be kept small and routed away from sensitive feedback traces.
For 2 A output at 36 V input and 3.3 V output, the power dissipation is approximately 3.6 W (calculated as (36-3.3)*2 A - output power). The 14-pin VQFN package has a thermal resistance around 40°C/W (estimate), so junction temperature rise is about 144°C at 25°C ambient. Ensure a copper pour of at least 1 square inch under the device to keep the junction below 150°C.
Do not exceed the 36 V input rating; use a TVS diode for load-dump protection. Ensure the enable pin is pulled up through a resistor to VIN for automatic start-up. The FB divider, if used, must use 1% tolerance resistors to maintain accuracy. Connect the BOOT pin capacitor between BOOT and SW (100 nF) as per the datasheet.
Compliance Information
Automotive qualified (AEC-Q100) per TI product page. RoHS/REACH status not explicitly confirmed in provided data; verify manufacturer documentation.
