Texas Instruments LM20145MHX/NOPB

Overview

LM20145MHX/NOPB from Texas Instruments is a 5A synchronous buck regulator with peak current mode control, adjustable switching frequency (250–750 kHz), integrated 32 mΩ high-side and 36 mΩ low-side FETs, and precision 0.8V feedback reference. It delivers regulated DC/DC conversion from 2.95V–5.5V input to adjustable output voltages down to 0.8V, supporting FPGA, DSP, and ASIC core power in space-constrained industrial and telecom systems.

For engineers reviewing the LM20145MHX/NOPB datasheet, LM20145MHX/NOPB pinout, LM20145MHX/NOPB application, or LM20145MHX/NOPB equivalent, key selection criteria include pre-biased start-up capability, ±10 mV SS/TRK tracking accuracy, 7.4A current limit threshold, thermal shutdown at 160°C, and HTSSOP-16 exposed-pad thermal performance.

Technical Context

The LM20145MHX/NOPB implements nonlinear parabolic slope compensation to maintain stability across 0.8V–5.5V output ranges without external tuning. Its peak current mode architecture uses cycle-by-cycle current limiting, inherent line feed-forward, and 80 ns current-sense blanking for robust transient response.

It integrates dual MOSFETs with matched R_DS(on) (32/36 mΩ), a 2.7V internal sub-regulator (VCC), analog bias supply filtering via AVIN/AGND, and precision enable with 1.18V turn-on threshold and 66 mV hysteresis-enabling accurate multi-rail sequencing and UVLO override.

Key Specifications

Pinout & Package

LM20145MHX/NOPB is housed in a 16-pin HTSSOP package with exposed thermal pad (Package Number PWP0016A), requiring solder connection to PCB ground plane for θ_JA = 38°C/W performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS54560QDGQRQ1 and MP2315GJ-Z, LM20145MHX/NOPB uniquely combines 2.95–5.5V input compatibility, pre-biased start-up, SS/TRK tracking, and adjustable frequency-making it optimal for compact, multi-rail digital power systems where input voltage headroom and sequencing fidelity are constrained.

Availability

LM20145MHX/NOPB is available at Aetrix Electronics and suitable for FPGA core power, DSP voltage scaling, optical line card biasing, and industrial PLC I/O modules requiring stable component supply across extended temperature and long production lifecycles.

Supply support for LM20145MHX/NOPB 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 LM20145 product line delivers highly integrated, thermally optimized synchronous buck regulators for space-constrained digital power applications-designed specifically for FPGA, ASIC, and DSP core voltage domains requiring precision regulation and robust fault handling.

FAQ

What is the minimum output voltage supported by the LM20145MHX/NOPB?

The LM20145MHX/NOPB supports an adjustable output voltage down to 0.8V, set by the feedback resistive divider connected to the FB pin. This 0.8V reference is accurate to ±12 mV over temperature and load, enabling direct regulation of modern low-voltage processor cores without external reference scaling. The LM20145MHX/NOPB achieves this using an internal 800 mV bandgap reference connected to the non-inverting input of its transconductance error amplifier.

Does the LM20145MHX/NOPB support startup into a pre-biased output?

Yes, the LM20145MHX/NOPB supports pre-biased start-up: when the output voltage is non-zero at power-on, the device will not sink current through the low-side FET until the internal soft-start ramp exceeds the FB pin voltage. This behavior prevents damage to downstream loads connected via parasitic paths-critical in multi-rail FPGA and ASIC systems. The LM20145MHX/NOPB implements this via its SS/TRK pin architecture and internal current-limit hysteresis.

How is switching frequency adjusted on the LM20145MHX/NOPB?

Switching frequency on the LM20145MHX/NOPB is set by connecting an external resistor between the RT pin and ground. The relationship is approximately f_SW ≈ 78 kΩ / R_RT – 55 kHz, allowing adjustment from 250 kHz (R_RT = 249 kΩ) to 750 kHz (R_RT = 49.9 kΩ). This resistor directly controls the oscillator timing current, and the LM20145MHX/NOPB maintains ±10% frequency accuracy over temperature and input voltage.

What thermal management features does the LM20145MHX/NOPB include?

The LM20145MHX/NOPB includes integrated thermal shutdown triggered at 160°C junction temperature, with 10°C hysteresis to prevent oscillation near the trip point. Its HTSSOP-16 package features an exposed thermal pad (EP) that must be soldered to the PCB ground plane to achieve the specified θ_JA of 38°C/W. The LM20145MHX/NOPB also uses internal thermal derating to reduce switching activity before shutdown, improving system robustness under sustained overload.

Can the LM20145MHX/NOPB track another voltage rail during startup?

Yes, the LM20145MHX/NOPB supports voltage tracking via its SS/TRK pin: when driven by an external voltage source below 800 mV, the pin overrides the internal reference and forces the FB node to follow the applied voltage with ±10 mV accuracy. This enables coordinated ramp-up with higher-voltage rails-such as tracking a 5V I/O supply while ramping a 1.2V core rail. The LM20145MHX/NOPB implements this using an internal 5 µA current source and comparator architecture referenced to V_FB.