Texas Instruments LMR33620BDDAR

Overview

LMR33620BDDAR from Texas Instruments is a synchronous step-down DC/DC converter optimized for rugged industrial power conversion. It operates from 3.8 V to 36 V input, delivers up to 2 A output current, supports adjustable 1 V–24 V output voltage, and features 1.4 MHz fixed switching frequency in the 8-pin HSOIC package. It is deployed in motor drive inverters and PLC CPU power rails where wide VIN, high efficiency, and thermal robustness are critical.

For engineers reviewing the LMR33620BDDAR datasheet, LMR33620BDDAR pinout, LMR33620BDDAR application, or LMR33620BDDAR equivalent, key selection criteria include its 1.4 MHz operation in HSOIC, 25 µA quiescent current, integrated compensation, precision enable threshold (1.231 V typ), and power-good flag with glitch filtering - all validated for industrial temperature range (–40°C to +125°C).

Technical Context

The LMR33620BDDAR implements peak-current-mode control with automatic PFM/PWM mode transition to maintain >95% peak efficiency across load range. Its 75 ns minimum on-time (DDA package) enables high VIN-to-VOUT step-down ratios, such as 24 V → 3.3 V at 1.4 MHz without dropout.

It integrates internal 5-V LDO (VCC), bootstrap driver (BOOT), analog ground (AGND), and open-drain power-good (PG) with 105%–107% upper and 90%–95% lower thresholds - all referenced to FB's 1.0 V nominal reference. Protection includes cycle-by-cycle current limit, hiccup short-circuit response, thermal shutdown (165°C), and input UVLO.

Key Specifications

Pinout & Package

LMR33620BDDAR is housed in an 8-pin HSOIC (5.00 mm × 4.00 mm) with PowerPAD™ thermal pad. The package supports high-power density PCB layouts with low-inductance VIN/PGND routing and integrated thermal dissipation via bottom-side copper exposure.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMR33620BDDAR, LMR33620ADDAR trades higher efficiency at lower frequency for relaxed EMI filtering, while LMR33620CRNXR offers superior power density and faster transient response in a smaller package - neither is pin-compatible, requiring layout revision.

Availability

LMR33620BDDAR is available at Aetrix Electronics and suitable for motor drive inverters, PLC CPU power supplies, and HVAC control units requiring stable component supply, long-term industrial lifecycle support, and AEC-Q100-qualified alternatives.

Supply support for LMR33620BDDAR 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 industrial and automotive qualification expertise.

The LMR33620 product line delivers SIMPLE SWITCHER® synchronous buck regulators engineered for rugged industrial environments - emphasizing wide input range, high reliability, integrated protection, and ease-of-use for power system designers.

FAQ

What is the switching frequency of the LMR33620BDDAR?

The LMR33620BDDAR operates at a fixed 1.4 MHz switching frequency. This value is factory-trimmed and non-adjustable. It enables compact magnetics and predictable EMI behavior, supporting designs where board space is constrained but 2 MHz-band EMI compliance is required. The 1.4 MHz frequency is specific to the "B" variant in the DDA (HSOIC) package - other variants use 400 kHz or 2.1 MHz.

Does the LMR33620BDDAR require external compensation components?

No, the LMR33620BDDAR includes an integrated compensation network. This eliminates the need for external Type-II or Type-III compensation networks, reducing bill-of-materials count and simplifying layout. The internal compensation is optimized for stability with standard output capacitor ESR ranges and common inductor values used in 1.4 MHz designs.

What is the function of the PG pin on the LMR33620BDDAR?

On the LMR33620BDDAR, the PG (power-good) pin is an open-drain output that signals when the regulated output voltage is within ±5% of its target (105%–107% upper, 90%–95% lower thresholds). It asserts high after soft-start completes and remains high unless triggered by overcurrent, thermal shutdown, or undervoltage. A 60–170 µs glitch filter prevents false triggering during transients.

Can the LMR33620BDDAR operate with an input voltage below 3.8 V?

No, the absolute minimum input voltage for the LMR33620BDDAR is 3.8 V under recommended operating conditions. Operation below this level may cause UVLO activation, disabling regulation. The device's 75 ns minimum on-time and peak-current-mode architecture are designed to sustain regulation down to 3.8 V - attempting lower inputs risks dropout, instability, or failure to start.

What thermal performance can be expected from the LMR33620BDDAR in HSOIC package?

The LMR33620BDDAR in HSOIC (DDA) package has a simulated junction-to-ambient thermal resistance (R_θJA) of 42.9°C/W on a 4-layer JEDEC board. In real-world industrial PCBs with 2 oz copper and thermal vias under the PowerPAD™, typical temperature rise is ~35°C at 2 A load and 24 V input. Derating begins above 125°C junction, with thermal shutdown activating at 165°C.