Texas Instruments LM2672MX-3.3

Overview

LM2672MX-3.3 from Texas Instruments is a monolithic 1-A step-down (buck) DC-DC switching regulator with fixed 3.3-V output, 260-kHz internal oscillator, ±1.5% output voltage tolerance over line/load/temperature, 8 V to 40 V input range, and integrated DMOS power switch. It delivers high-efficiency power conversion in industrial control, embedded systems, and point-of-load regulation where compact size and thermal simplicity are critical.

For engineers reviewing the LM2672MX-3.3 datasheet, LM2672MX-3.3 pinout, LM2672MX-3.3 application, or LM2672MX-3.3 equivalent, key selection criteria include its fixed 3.3-V output accuracy, 1-A continuous load capability, TTL-compatible ON/OFF control, soft-start functionality, and compatibility with standard external components (inductor, Schottky diode, input/output capacitors) per TI's validated reference design.

Technical Context

The LM2672MX-3.3 implements a fixed-frequency PWM buck topology using an internal DMOS power MOSFET switch with 0.3 Ω typical R_DS(ON). Its 260-kHz oscillator enables use of small passive filter components while maintaining >90% efficiency at 1 A load - e.g., 86% at VIN = 12 V, I_LOAD = 1 A. The device integrates internal frequency compensation, current-limit protection (1.25–2.1 A), thermal shutdown, and soft-start via external capacitor.

Control logic includes TTL-compatible ON/OFF enable (1.4 V threshold), SYNC input for external clock synchronization up to 400 kHz, and dedicated FB pin tied directly to output for fixed-voltage regulation. The CB pin supports bootstrap gate drive for high-side FET enhancement, requiring a 0.01-μF ceramic capacitor between CB and VSW.

Key Specifications

Pinout & Package

LM2672MX-3.3 is packaged in an 8-pin SOIC (D package) with 5.00 mm × 6.20 mm body size and standard surface-mount footprint. Thermal resistance R_θJA = 105°C/W enables operation at full 1-A load in ambient temperatures up to 85°C with minimal board-level heatsinking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2672M-3.3, the LM2672MX-3.3 offers superior thermal performance and SMT manufacturability; compared with LM2596SX-3.3/NOPB, it provides tighter output tolerance and simpler external component count at the cost of lower current rating - making LM2672MX-3.3 optimal for precision 1-A 3.3-V point-of-load applications.

Availability

LM2672MX-3.3 is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and medical device applications requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.

Supply support for LM2672MX-3.3 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 LM2672MX-3.3 belongs to TI's SIMPLE SWITCHER® family - designed specifically for ease-of-use, minimal external component count, and robust operation in industrial, automotive, and communications power supplies.

FAQ

What is the maximum input voltage rating for the LM2672MX-3.3?

The LM2672MX-3.3 has an absolute maximum input voltage rating of 45 V, with recommended operating range from 8 V to 40 V. Operation above 40 V is not advised for long-term reliability, and transient spikes beyond 45 V may cause permanent damage. For automotive applications subject to load dump, external TVS protection is recommended before the VIN pin of the LM2672MX-3.3.

Does the LM2672MX-3.3 require external feedback resistors to set its output voltage?

No, the LM2672MX-3.3 does not require external feedback resistors. As a fixed-output variant, it integrates internal resistor dividers to regulate precisely to 3.3 V. The FB pin is internally connected to the output stage and must be tied directly to the output capacitor - no external components are needed on the FB net, simplifying layout and improving accuracy versus adjustable versions.

Can the LM2672MX-3.3 be synchronized to an external clock source?

Yes, the LM2672MX-3.3 supports external clock synchronization via its SYNC pin. When driven with a TTL- or CMOS-compatible square wave ≥275 kHz, the internal 260-kHz oscillator locks to the external frequency. This feature enables EMI reduction through frequency dithering or alignment with system clocks. Note that current-limit frequency foldback is disabled during SYNC operation.

What is the purpose of the CB pin on the LM2672MX-3.3?

The CB (bootstrap capacitor) pin on the LM2672MX-3.3 provides gate drive voltage boosting for the internal high-side DMOS switch. A 0.01-μF ceramic capacitor must be connected between CB and VSW to generate a voltage ~VIN + 10 V at the gate, ensuring full enhancement and minimizing R_DS(ON). Omitting or undersizing this capacitor causes excessive conduction loss and potential thermal failure of the LM2672MX-3.3.

How does the ON/OFF pin function on the LM2672MX-3.3?

The ON/OFF pin of the LM2672MX-3.3 enables TTL-compatible enable/disable control: pulling below 1.4 V shuts down the regulator, reducing quiescent current to 50–100 μA; pulling above 1.4 V activates switching. An internal 20-μA pull-up allows direct connection to open-drain GPIOs. Floating the pin enables continuous operation - no external pull-up is required for basic use of the LM2672MX-3.3.