Texas Instruments LM46001PWPT

Overview

LM46001PWPT from Texas Instruments is a 3.5-V to 60-V, 1-A synchronous step-down DC-DC converter in HTSSOP-16 package. It delivers regulated output voltage (adjustable from 1 V to 28 V) with peak-current-mode control, 24-µA quiescent current in regulation, and integrated high-side/low-side MOSFETs (R_DS(on) = 419 mΩ / 231 mΩ). It enables compact, high-efficiency power conversion in industrial and automotive sub-AM band supplies.

For engineers reviewing the LM46001PWPT datasheet, LM46001PWPT pinout, LM46001PWPT application, or LM46001PWPT equivalent, key selection criteria include input voltage range (3.5–60 V), light-load efficiency via DCM/PFM modes, EN pin precision UVLO (2.1 V ±305 mV), PGOOD flag, and 500 kHz default switching frequency with external RT programmability (200 kHz–2.2 MHz).

Technical Context

The LM46001PWPT employs fixed-frequency peak-current-mode control with automatic transition to discontinuous conduction mode (DCM) and pulse frequency modulation (PFM) at light loads to maintain high efficiency across 0–1 A output. Its internal compensation eliminates external loop components, while the RT pin enables precise frequency tuning or synchronization to an external clock (200 kHz–2.2 MHz).

It integrates dual N-channel MOSFETs, a precision 1.016-V feedback reference (±12 mV over –40°C to +125°C), soft-start with 4.1-ms internal timing (extendable via SS/TRK capacitor), and comprehensive protection including hiccup-mode short-circuit response, thermal shutdown (160°C), and cycle-by-cycle current limiting (peak 2.45 A, valley 1.1 A).

Key Specifications

Pinout & Package

The LM46001PWPT is housed in a 16-pin HTSSOP (PWP) package measuring 6.6 mm × 5.1 mm × 1.2 mm with 0.65-mm lead pitch. The exposed thermal pad (Pin 17) must be soldered to PCB ground for effective heat dissipation (R_θJB = 21.7°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down converter applications.

Compared with LM46001PWPT, LM46002PWPT offers scalable current capacity in the same footprint, while LM43603PWPT trades precision features for raw power - making LM46001PWPT optimal for cost-sensitive, feature-rich 1-A applications demanding PGOOD, tracking, and ultra-low IQ.

Availability

LM46001PWPT is available at Aetrix Electronics and suitable for industrial power supplies, telecommunications systems, and sub-AM band automotive applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance.

Supply support for LM46001PWPT 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 power management technologies, with decades of expertise in high-reliability power conversion ICs.

The LM46001PWPT belongs to TI's wide-input synchronous buck regulator product line, engineered for robust, compact, and efficient DC-DC conversion in harsh environments such as factory automation, telecom infrastructure, and vehicle electronics.

FAQ

What is the minimum input voltage required for the LM46001PWPT to start switching?

The LM46001PWPT requires a minimum input voltage of 3.8 V to initiate startup and enter regulation. This threshold ensures reliable turn-on of the internal LDO and gate drivers under all temperature and load conditions. Below 3.8 V, the device remains in shutdown regardless of EN pin state. Once started, it continues regulating down to 3.5 V input.

Can the LM46001PWPT safely start up into a pre-biased output capacitor?

Yes, the LM46001PWPT supports soft-start into a pre-biased output. Its internal control architecture prevents reverse current flow during startup by holding the high-side MOSFET off until the internal soft-start ramp exceeds the existing output voltage. This avoids damaging downstream circuitry and eliminates need for external reverse-current protection diodes in hot-swap or multi-rail systems using LM46001PWPT.

How does the BIAS pin improve efficiency in the LM46001PWPT?

The BIAS pin improves efficiency by powering the internal high-side gate driver from the regulated output (when VOUT is 3.3–28 V) instead of the main VIN rail. This reduces switching losses in the high-side MOSFET, especially at high input-to-output voltage ratios. When BIAS is tied to VOUT, LM46001PWPT achieves up to 2% higher full-load efficiency compared to BIAS grounded - verified across 24-V and 48-V input conditions.

What is the purpose of the SS/TRK pin on the LM46001PWPT, and how is it used for voltage tracking?

The SS/TRK pin serves dual functions: internal soft-start timing and external voltage tracking. For tracking, apply a controlled voltage ramp (e.g., from another regulator's soft-start pin) to SS/TRK. The LM46001PWPT then regulates its output to follow that ramp with 1:1 ratio, enabling coordinated power-up of multiple rails. This eliminates sequencing ICs in FPGA or processor power systems where LM46001PWPT supplies auxiliary or core voltages.

Does the LM46001PWPT require external compensation components?

No, the LM46001PWPT features fully internal compensation. Its control loop is factory-tuned for stability across all recommended operating conditions and common output capacitor types (ceramic, polymer, tantalum, aluminum). No external RC networks or compensation capacitors are needed - reducing BOM count, PCB area, and design validation effort for standard applications using LM46001PWPT.