Texas Instruments LM5118Q1MHX/NOPB – Automotive 76‑V Non‑Inverting Buck‑Boost Controller (HTSSOP‑20)
The Texas Instruments LM5118Q1MHX/NOPB is an automotive‑qualified, wide‑input, non‑inverting buck‑boost PWM controller that regulates a stable output across large input variations typical of vehicle batteries and industrial rails. Part of the LM5118‑Q1 family, this controller seamlessly transitions between buck, buck‑boost, and boost modes, driving external N‑channel MOSFETs to deliver robust performance in demanding environments. Available in a compact 20‑pin HTSSOP (PowerPAD) package and supplied in tape‑and‑reel, it is a strong fit for engineers designing reliable power stages in AEC‑Q100 systems.
At a Glance
- Brand/manufacturer: Texas Instruments
- MPN/Series: LM5118Q1MHX/NOPB (LM5118‑Q1 family)
- Topology: Non‑inverting buck‑boost (2‑switch)
- Wide input capability: Up to 76 V (max)
- Adjustable switching frequency: Typical range ~50 kHz to 500 kHz
- Driver stage: Controls external N‑channel MOSFETs
- Protection: UVLO, current limit, thermal shutdown
- Soft‑start: Programmable
- Operating temperature: −40 °C to +125 °C (ambient)
- Package: HTSSOP‑20 (PowerPAD), Surface‑mount; Tape & Reel (TR)
- Qualification/Compliance: Automotive AEC‑Q100; RoHS compliant (lead‑free)
Why Choose LM5118Q1MHX/NOPB for Automotive and Wide‑Input Designs
Designers of automotive ECUs, transportation controllers, and 12‑V/24‑V industrial systems often face large and fast input swings, cold‑crank sags, and load‑dump transients. The Texas Instruments LM5118Q1MHX/NOPB directly addresses these challenges by regulating through buck, buck‑boost, and boost regions without changing control schemes. This results in a simpler power path for applications that need a non‑inverting regulated rail, regardless of whether the input is above, below, or near the desired output.
Because the LM5118‑Q1 drives external MOSFETs, you can scale current capability and efficiency by choosing appropriate FETs and diodes for your load and thermal goals. The adjustable switching frequency (typ. ~50 kHz to 500 kHz) lets you balance EMI, efficiency, and solution size—tuning the power stage to your application’s constraints. Programmable soft‑start helps manage inrush and meet system sequencing requirements, while integrated UVLO, current limit, and thermal shutdown add robust protection.
Key Features and Benefits
- Wide input range up to 76 V
- Suitable for automotive battery rails and industrial buses, where high‑voltage transients must be tolerated within design limits.
- Non‑inverting buck‑boost operation
- Seamlessly crosses buck, buck‑boost, and boost regions to hold the output steady as input varies.
- External N‑channel MOSFET drive
- Enables flexible power stage scaling to match efficiency and current needs.
- Adjustable switching frequency (typ. ~50 kHz to 500 kHz)
- Lets designers trade off EMI, size, and efficiency to meet project goals.
- Programmable soft‑start
- Controls start‑up behavior and inrush current profile.
- Integrated protections: UVLO, current limit, thermal shutdown
- Adds resilience under fault or out‑of‑spec conditions.
- AEC‑Q100 qualified and −40 °C to +125 °C ambient operation
- Ready for automotive environments and extended temperature ranges.
- HTSSOP‑20 (PowerPAD) package
- Compact footprint with exposed pad for improved thermal performance.
Typical Applications
- Automotive battery regulation and power stabilizers
- 12‑V/24‑V industrial and transportation systems
- Wide‑input DC power supplies and pre‑regulators
These use cases benefit from the LM5118Q1MHX/NOPB’s ability to maintain regulation across large input excursions. The part’s non‑inverting architecture is well‑suited to rails that must retain the same polarity as the source while handling battery sags and surges.
Specifications
- Brand/Manufacturer: Texas Instruments
- MPN: LM5118Q1MHX/NOPB
- Series: LM5118‑Q1
- Category: Power Management ICs > DC‑DC Controllers > Buck‑Boost Controllers
- Topology: Non‑inverting buck‑boost (2‑switch)
- Input voltage (max): 76 V
- Adjustable switching frequency: Yes (typical range ~50 kHz to 500 kHz)
- Soft‑start: Programmable
- Protection features: UVLO, current limit, thermal shutdown
- Qualification: Automotive AEC‑Q100
- Operating temperature range: −40 °C to +125 °C (ambient)
- Package: HTSSOP‑20 (PowerPAD)
- Pin count: 20
- Mounting type: Surface Mount
- Packaging: Tape & Reel (TR)
- RoHS status: RoHS Compliant (Lead‑free)
Note: The LM5118‑Q1 is a non‑synchronous, 2‑switch controller that uses external MOSFETs and diodes. For 4‑switch synchronous operation, see the LM517x family.
Design Considerations and Best Practices
While every power stage is unique, the following considerations can help you extract the most from the LM5118Q1MHX/NOPB:
- Power stage component selection
- Choose MOSFETs and diodes with appropriate voltage and current ratings for the intended input range, load, and thermal environment. Because the controller is non‑synchronous, diode selection has an impact on efficiency and thermal performance.
- Frequency selection and EMI
- Use the adjustable frequency capability to align switching harmonics with your EMI strategy. Layout and filtering are crucial to meeting automotive EMC targets.
- Soft‑start and sequencing
- Program soft‑start to manage inrush current and coordinate with downstream loads. This can be important when powering sensitive digital or RF subsystems.
- UVLO thresholds
- Properly set undervoltage lockout to ensure clean startup and prevent operation in undervoltage regions that can stress components.
- Layout and thermal management
- Solder the PowerPAD to a solid ground plane to reduce thermal impedance and noise. Short, wide traces for high‑di/dt paths and generous local decoupling at the MOSFETs and controller are recommended. Follow TI’s datasheet layout guidance.
These practices are general guidelines; always verify your design against the Texas Instruments datasheet and perform validation under worst‑case conditions.
Compliance and Environmental
- AEC‑Q100: Automotive qualified
- RoHS: Lead‑free, RoHS compliant
- Environmental operation: −40 °C to +125 °C (ambient)
- Resilience: Designed for wide input voltage conditions up to 76 V
If your program requires additional compliance (for example, functional safety or specific OEM requirements), consult TI resources and your quality organization. Functional safety certifications are not specified in the provided datasheet information.
Lifecycle, Replacements, and Alternates
- Lifecycle status: Active (per Texas Instruments product page)
- Primary recommended migration (new designs): LM5175‑Q1
- Type: 4‑switch synchronous buck‑boost controller
- Compatibility: Not pin‑compatible
- Notes: Consider for higher efficiency and advanced features in new designs; evaluate system‑level differences before substitution.
Approved alternates policy: Engineering review required; alternates are not drop‑in compatible.
Ordering, Packaging, and Availability
- Orderable part: LM5118Q1MHX/NOPB
- Package: HTSSOP‑20 (PowerPAD)
- Packaging format: Tape & Reel (TR)
- Lead finish: Lead‑free (RoHS compliant)
Availability: Check Texas Instruments and authorized distributors for current stock and lead times. Automotive‑graded devices can have region‑ and volume‑dependent pricing; contact for quote if you need program‑level volumes or long‑term supply commitments.
Note on suffix: The “MHX/NOPB” ordering code denotes the HTSSOP‑20 package, tape‑and‑reel distribution, and lead‑free finish.
How LM5118‑Q1 Compares to Newer TI Buck‑Boost Controllers
- LM5118‑Q1 (this device)
- Non‑inverting buck‑boost, 2‑switch architecture
- External MOSFETs and diodes
- Adjustable frequency, programmable soft‑start, UVLO, current limit, thermal shutdown
- LM5175‑Q1 (alternative)
- 4‑switch synchronous buck‑boost controller
- Not pin‑compatible; typically offers higher efficiency due to synchronous rectification
When designing for maximum efficiency or tighter EMI control, evaluating the LM5175‑Q1 may be advantageous. For established designs or when the 2‑switch non‑inverting architecture is preferred, the LM5118Q1MHX/NOPB remains a dependable choice.
Applications in Focus
- Automotive battery regulation
- Stabilize 5 V, 12 V, or other rails from a vehicle battery that can dip or surge depending on operating conditions.
- 24‑V industrial/transportation systems
- Maintain regulated outputs in forklifts, AGVs, and other platforms where the bus can vary widely.
- Wide‑input pre‑regulators
- Front‑end regulation for systems that must accept a broad range of adapters or sources.
These scenarios leverage the device’s seamless transition through buck and boost regions to keep output rails stable.
Frequently Asked Questions (FAQs)
Q: What does the “Q1” suffix indicate?
A: It denotes AEC‑Q100 automotive qualification.
Q: Is LM5118‑Q1 a synchronous buck‑boost controller?
A: No. It is a 2‑switch, non‑inverting buck‑boost controller that uses external MOSFETs and diodes. For 4‑switch synchronous operation, consider the LM517x devices (e.g., LM5175‑Q1).
Q: What is the maximum input voltage the LM5118Q1MHX/NOPB can handle?
A: Up to 76 V, per the device specifications.
Q: What switching frequency range can I use?
A: The switching frequency is adjustable; typical range is approximately 50 kHz to 500 kHz.
Q: Does the controller integrate the power MOSFETs?
A: No. The LM5118‑Q1 drives external N‑channel MOSFETs, allowing you to scale current and efficiency.
Q: What protection features are included?
A: UVLO, current limit, and thermal shutdown are supported.
Q: What is the operating temperature range?
A: −40 °C to +125 °C (ambient).
Q: Which package and mounting style does LM5118Q1MHX/NOPB use?
A: HTSSOP‑20 with an exposed PowerPAD, surface‑mount, supplied in Tape & Reel.
Q: Is the device RoHS compliant?
A: Yes, it is lead‑free and RoHS compliant.
Q: Is this a drop‑in replacement for LM5175‑Q1?
A: No. The LM5175‑Q1 is not pin‑compatible and uses a different 4‑switch synchronous architecture.
Q: Is functional safety certification provided?
A: Not specified in the datasheet; consult TI if your program requires specific functional safety documentation.
Resources
- Product page: https://www.ti.com/product/LM5118-Q1
- Datasheet: https://www.ti.com/lit/ds/symlink/lm5118-q1.pdf
If a parameter is not listed here, refer to the official Texas Instruments documentation. This article focuses on the LM5118Q1MHX/NOPB orderable variant and summarizes features and specifications provided by TI to help engineers and sourcing teams evaluate fit, plan procurement, and accelerate design‑in.