Texas Instruments LM20133MHX/NOPB

Overview

LM20133MHX/NOPB from Texas Instruments is a 3A synchronous buck regulator with peak current mode control, 2.95V–5.5V input range, and integrated 32 mΩ/36 mΩ high-side/low-side FETs. It delivers regulated output down to 0.8V with ±1.5% feedback accuracy, supports pre-biased startup, and targets point-of-load regulation for FPGA/DSP core supplies.

For engineers reviewing the LM20133MHX/NOPB datasheet, LM20133MHX/NOPB pinout, LM20133MHX/NOPB application, or LM20133MHX/NOPB equivalent, key selection criteria include its 410 kHz nominal switching frequency, SYNC pin compatibility with 500 kHz–1.5 MHz external clocks, precision enable threshold (1.18V typ), and HTSSOP-16 exposed-pad thermal performance.

Technical Context

The LM20133MHX/NOPB implements peak current mode control with nonlinear parabolic slope compensation-dynamically adjusted per output voltage-to ensure stability across 0.8V–5.5V VOUT without external loop tuning beyond COMP pin RC network. Its internal 2.7V sub-regulator (VCC) powers bias circuitry, while AVIN/AGND separation isolates analog reference paths from power-switch noise.

Protection architecture includes cycle-by-cycle overcurrent limiting (5.2A typ), thermal shutdown at 160°C with 10°C hysteresis, OVP at 108% of VFB with 3% hysteresis, and UVLO with 2.7V turn-on threshold and 45mV hysteresis. The PGOOD open-drain flag provides 16µs deglitching and 94% VFB rising threshold.

Key Specifications

Pinout & Package

LM20133MHX/NOPB uses a 16-pin HTSSOP package (PWP0016A) with exposed thermal pad (EP) electrically tied to PGND. The exposed pad must be soldered to PCB ground plane for thermal compliance at 3A load.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS54332DR and LM2678SD-ADJ/NOPB, LM20133MHX/NOPB uniquely combines 3A capability, SYNC pin flexibility, SS/TRK tracking, and HTSSOP thermal performance-making it optimal for compact, multi-rail embedded systems requiring precise sequencing and EMI control.

Availability

LM20133MHX/NOPB is available at Aetrix Electronics and suitable for FPGA power delivery, optical transceiver modules, and industrial PLC I/O regulation requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM20133MHX/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 over 90 years of innovation in high-reliability components.

The LM20133MHX/NOPB belongs to TI's PowerWise® synchronous buck regulator family, engineered for high-efficiency, low-voltage point-of-load conversion in space-constrained digital systems such as processors, FPGAs, and communications infrastructure.

FAQ

What is the maximum output current capability of the LM20133MHX/NOPB?

The LM20133MHX/NOPB delivers up to 3A of continuous output current under thermal-limited conditions. Its 32 mΩ high-side and 36 mΩ low-side integrated FETs, combined with the HTSSOP-16 exposed pad, enable this rating when the PCB provides adequate copper area for heat dissipation. Peak current limit is specified at 5.2A typical, supporting brief transients beyond 3A.

Does the LM20133MHX/NOPB support startup into a pre-biased output?

Yes, the LM20133MHX/NOPB supports pre-biased startup. During power-up, it does not sink current from the output-even if VOUT is already present-until the internal soft-start ramp on the SS/TRK pin exceeds the voltage at the FB pin. This prevents reverse current flow through load parasitics, protecting devices like FPGAs and ASICs during multi-rail sequencing.

How is the switching frequency set on the LM20133MHX/NOPB?

The LM20133MHX/NOPB operates at approximately 410 kHz when the SYNC pin is left unconnected or grounded. To synchronize to an external clock, apply a clean square wave between 500 kHz and 1.5 MHz to the SYNC pin, with logic-high ≥2.0V and logic-low ≤0.8V. The high-side FET turn-on is locked to the rising edge of the SYNC signal.

What is the purpose of the AVIN and AGND pins on the LM20133MHX/NOPB?

The AVIN pin supplies filtered power to the internal analog bias circuitry-including the error amplifier and reference-while AGND serves as the quiet ground reference for those same circuits. AVIN must be connected to PVIN through an RC filter (e.g., 10Ω + 1µF) to suppress switch-node noise; AGND must be tied to PGND at a single point near the exposed pad to avoid ground loops and maintain feedback accuracy.

Can the LM20133MHX/NOPB be used to track another voltage rail?

Yes, the LM20133MHX/NOPB supports voltage tracking via the SS/TRK pin. When driven by an external voltage source below 0.8V, the output tracks that source with ±15 mV accuracy relative to the FB pin. This enables coordinated power-up of multiple rails-such as FPGA core and I/O voltages-without additional tracking ICs or complex sequencing controllers.