Texas Instruments LM46000PWPT

Overview

LM46000PWPT from Texas Instruments is a 3.5-V to 60-V, 0.5-A synchronous step-down DC-DC converter in HTSSOP-16 (PWP) package. It delivers regulated output with 24-µA quiescent current in regulation, 500-kHz default switching frequency, and integrated synchronous rectification. Used in industrial power supplies and sub-AM band automotive systems where wide-input, high-efficiency point-of-load conversion is required.

For engineers reviewing the LM46000PWPT datasheet, LM46000PWPT pinout, LM46000PWPT application, or LM46000PWPT equivalent, key selection criteria include input voltage range (3.5–60 V), light-load efficiency via DCM/PFM, EN55022 Class B EMI compliance, precision enable threshold (2.1 V typ), and internal soft-start (4.1 ms).

Technical Context

The LM46000PWPT employs peak-current-mode control with fixed-frequency PWM, supporting discontinuous conduction mode (DCM) and pulse-frequency modulation (PFM) at light loads to maintain high efficiency across 0–0.5 A. Its internal compensation eliminates external loop components, while the RT pin enables adjustable switching frequency from 200 kHz to 2.2 MHz.

It integrates dual MOSFETs (R_DS(on)-HS = 419 mΩ, R_DS(on)-LS = 231 mΩ), a precision 1.016-V feedback reference, and protection features including hiccup-mode short-circuit response, thermal shutdown at 160°C, and cycle-by-cycle current limiting with 1.35-A peak limit.

Key Specifications

Pinout & Package

LM46000PWPT 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 thermal performance (R_θJA = 39.9°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck regulator applications.

Compared with LM46000PWPT, LM46001PWPT offers higher current capacity in the same footprint for future-proofing, while LM43603PWPT targets significantly higher power tiers with revised thermal and control-loop characteristics - neither is pin-compatible beyond shared package outline.

Availability

LM46000PWPT 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 guaranteed traceability.

Supply support for LM46000PWPT 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 decades of expertise in power management ICs for industrial, automotive, and communications markets.

The LM46000PWPT belongs to TI's wide-input synchronous buck regulator family, designed specifically for high-reliability, space-constrained applications demanding wide VIN range, low IQ, and EMI-compliant operation without complex layout constraints.

FAQ

What is the minimum input voltage required for the LM46000PWPT to start switching?

The LM46000PWPT requires a minimum input voltage of 3.8 V to initiate startup and enter regulation. Below this threshold, the device remains in shutdown with only 2.3–5 µA quiescent current drawn from VIN. This ensures reliable turn-on across temperature and process variations while preventing unstable operation near the lower edge of its 3.5–60-V operating range. The LM46000PWPT will not switch or regulate until VIN exceeds 3.8 V.

Does the LM46000PWPT support output voltage tracking during power-up sequencing?

Yes, the LM46000PWPT supports output voltage tracking via the SS/TRK pin. When an external voltage ramp (e.g., from another regulator's soft-start pin) is applied to SS/TRK, the LM46000PWPT's output follows that ramp with unity gain. This enables precise power-up sequencing in multi-rail systems - for example, ensuring a 3.3-V rail tracks behind a 5-V rail to prevent back-powering or latch-up in FPGAs. Internal soft-start remains active if SS/TRK is left floating.

How does the LM46000PWPT achieve EN55022 Class B EMI compliance?

The LM46000PWPT achieves EN55022 Class B compliance through integrated features including slew-rate-controlled gate drivers, optimized internal node layout, and a spread-spectrum-capable oscillator (via SYNC pin). Measured radiated emissions on the LM46000PWPEVM meet Class B limits without additional filtering. Layout best practices - especially minimizing SW loop area and using the thermal pad as a shield - are essential to replicate this performance in end equipment.

Can the LM46000PWPT operate with ceramic output capacitors only?

Yes, the LM46000PWPT is explicitly designed to be stable with ceramic output capacitors - including X5R and X7R types - without requiring series resistance or additional ESR. Its internally compensated architecture and adaptive control loop eliminate the need for external compensation components. This simplifies BOM, reduces footprint, and improves transient response compared to regulators requiring polymer or tantalum capacitors for stability.

What thermal management provisions are built into the LM46000PWPT package?

The LM46000PWPT uses an HTSSOP-16 (PWP) package with an exposed thermal pad (Pin 17) that serves as the primary heat dissipation path. With proper PCB design - including soldering the pad to a ≥100 mm² internal or external ground plane - the device achieves R_θJA = 39.9°C/W. The pad is internally connected to PGND, so it must be tied to the system ground plane to ensure both thermal performance and EMI suppression. No heatsink is required for ≤0.5-A operation at ambient ≤85°C.