Texas Instruments LM20323MHX/NOPB

Overview

LM20323MHX/NOPB from Texas Instruments is a 36V, 3A synchronous buck regulator with fixed 500 kHz switching frequency, 130 mΩ/110 mΩ integrated high-side/low-side MOSFETs, and 0.8V adjustable output voltage. It delivers up to 3A continuous current with 93% peak efficiency and supports pre-biased startup in FPGA/DSP point-of-load applications.

For engineers reviewing the LM20323MHX/NOPB datasheet, LM20323MHX/NOPB pinout, LM20323MHX/NOPB application, or LM20323MHX/NOPB equivalent, key selection criteria include input voltage range (4.5–36V), precision enable threshold (1.25V typ), PGOOD open-drain signaling, soft-start/tracking capability, and thermal shutdown at 170°C.

Technical Context

The LM20323MHX/NOPB implements peak current mode control with non-linear parabolic slope compensation-dynamically adjusted per output voltage-to ensure stability across 0.8V–VIN×0.7 duty cycles. Its externally compensated error amplifier (gm = 515 µmho, GBW = 7 MHz) interfaces via COMP pin to standard Type II/III networks.

It integrates OVP (110% VFB threshold), UVLO (4.25V rising, 350 mV hysteresis), cycle-by-cycle current limit (5.2A peak), and thermal shutdown (170°C, 20°C hysteresis). The SS/TRK pin enables either programmable soft-start (4.5 µA internal current source) or monotonic voltage tracking of external rails.

Key Specifications

Pinout & Package

LM20323MHX/NOPB uses a thermally enhanced 20-pin HTSSOP package with exposed pad (PWP0020A), requiring PCB ground plane connection for optimal thermal performance (θJA = 27°C/W, θJC = 5.6°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM20323MHX/NOPB, LM20323MH/NOPB offers identical performance in non-MSL-constrained environments, while TPS54332DR trades integrated bootstrap functionality and advanced slope compensation for improved light-load IQ-making it suitable only where those specific trade-offs align with system priorities.

Availability

LM20323MHX/NOPB is available at Aetrix Electronics and suitable for FPGA power delivery, DSP point-of-load regulation, automotive infotainment SoC supplies, industrial PLC I/O modules, and telecom infrastructure DC-DC conversion requiring stable component supply and long-term manufacturability.

Supply support for LM20323MHX/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 ICs, with decades of expertise in high-reliability power conversion solutions.

The LM20323MHX/NOPB belongs to TI's high-voltage synchronous buck regulator product line, engineered for robust point-of-load conversion in industrial, automotive, and communications systems operating from 4.5V to 36V input buses.

FAQ

What is the maximum input voltage rating for LM20323MHX/NOPB?

The LM20323MHX/NOPB has an absolute maximum VIN-to-GND rating of +38V, but its specified operating range is +4.5V to +36V. Operation beyond 36V risks violating functional specifications-even if within absolute max-so designs must maintain VIN ≤ 36V under all conditions including transients. The device includes integrated OVP that triggers at 110% of VFB to protect downstream circuits.

Does LM20323MHX/NOPB support pre-biased output startup?

Yes, LM20323MHX/NOPB fully supports pre-biased startup: it will not sink current from a pre-charged output rail during soft-start. Instead, it waits until the internal soft-start ramp exceeds the FB pin voltage before enabling switching. This behavior prevents reverse current flow through parasitic paths in FPGA, ASIC, or multi-rail systems-preserving load integrity without external diodes or circuitry.

What is the purpose of the SS/TRK pin on LM20323MHX/NOPB?

The SS/TRK pin on LM20323MHX/NOPB serves dual functions: soft-start timing control and voltage tracking. When used for soft-start, an external capacitor sets ramp duration (e.g., 100 nF yields ~450 µs). For tracking, it follows an external voltage ramp-enabling coordinated power-up with higher-voltage rails. Internally, a 4.5 µA current source charges the capacitor, and the pin accepts low-impedance external sources for accurate tracking.

How does LM20323MHX/NOPB implement slope compensation?

LM20323MHX/NOPB uses non-linear (parabolic) slope compensation-unlike traditional linear ramps-to dynamically match compensation strength to output voltage. At higher VOUT, more slope is applied to prevent sub-harmonic oscillation; at lower VOUT, less slope preserves loop bandwidth and transient response. This eliminates manual compensation tuning across output voltages and improves stability margin across the full 0.8V–25V range.

What thermal management features does LM20323MHX/NOPB include?

LM20323MHX/NOPB integrates thermal shutdown at 170°C (typical) with 20°C hysteresis, causing automatic restart at ~150°C. Its 20-pin HTSSOP package includes an exposed pad thermally connected to GND, enabling direct PCB copper pour attachment for efficient heat transfer. Measured thermal resistance is θJC = 5.6°C/W and θJA = 27°C/W on a 4-layer board-allowing 3A continuous operation at 70°C ambient without forced airflow.