Texas Instruments LMR33620ADDA

Overview

LMR33620ADDA from Texas Instruments is a synchronous step-down DC/DC converter delivering 2 A output current across 3.8 V to 36 V input, with adjustable 1 V–24 V output, fixed 400 kHz switching frequency, and peak efficiency >95% in an 8-pin HSOIC package. It serves as the primary voltage regulator in industrial motor drives, PLC CPU power rails, and wide-VIN embedded systems requiring rugged operation from –40°C to +125°C.

For engineers reviewing the LMR33620ADDA datasheet, LMR33620ADDA pinout, LMR33620ADDA application, or LMR33620ADDA equivalent, key selection criteria include its 400 kHz fixed-frequency operation, 68 ns minimum on-time (DDA package), integrated compensation, precision enable threshold (1.231 V typical), and open-drain power-good flag with 170 µs glitch filter - all validated for industrial-grade reliability and EMI-sensitive layouts.

Technical Context

The LMR33620ADDA implements peak-current-mode control with automatic PFM/PWM mode transition to maintain high light-load efficiency. Its internal 5-V VCC LDO powers control circuitry, while the BOOT-SW bootstrap network enables high-side MOSFET drive with 95–160 mΩ R_DS(on).

It features cycle-by-cycle current limiting (ISC = 3.5 A typ), hiccup-mode short-circuit protection (94 ms burst interval), thermal shutdown at 165°C, and precision enable with 100 mV hysteresis - all operating within a –40°C to +125°C junction temperature range and supporting dropout operation down to VIN – VOUT = 150 mV at 1 A.

Key Specifications

Pinout & Package

LMR33620ADDA is housed in an 8-pin HSOIC (5.00 mm × 4.00 mm) package with PowerPAD™ thermal pad. The exposed pad must be soldered to a PCB ground plane for optimal thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMR33620BDDA and LMR33620ARNX, the LMR33620ADDA offers the lowest component count for 400 kHz designs, best-in-class light-load quiescent current (25 µA), and proven manufacturability in HSOIC - making it optimal for cost-sensitive, thermally moderate industrial power rails where layout simplicity and EMI predictability are prioritized.

Availability

LMR33620ADDA is available at Aetrix Electronics and suitable for motor drive systems, factory automation controllers, and general-purpose wide-VIN power supplies requiring stable component supply, long-term industrial lifecycle support, and AEC-Q100-qualified alternatives.

Supply support for LMR33620ADDA 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 experience in industrial-grade power solutions.

The LMR33620 series belongs to TI's SIMPLE SWITCHER® portfolio, engineered specifically for rugged industrial applications demanding wide input voltage range, high efficiency across load, and simplified design - including motor drives, PLCs, and building automation systems.

FAQ

What is the maximum output voltage supported by the LMR33620ADDA?

The LMR33620ADDA supports an adjustable output voltage range from 1 V to 24 V, set by an external resistor divider on the FB pin. The feedback reference voltage is 1.0 V ±1.5%, and the maximum output is limited to 95% of VIN under normal operation. For example, with a 36 V input, the practical maximum output is approximately 34.2 V - though the datasheet specifies 24 V as the guaranteed operational limit for stability and safety margins across temperature and load.

Does the LMR33620ADDA require external compensation components?

No, the LMR33620ADDA integrates a complete compensation network internally, eliminating the need for external Type-II or Type-III compensation networks. This reduces bill-of-materials count, simplifies PCB layout, and improves design robustness - especially for engineers without deep power-supply control-loop expertise. The device maintains stable regulation across its full 1 V–24 V output range and 0–2 A load without any external compensation parts.

What is the purpose of the PG (power-good) pin on the LMR33620ADDA?

On the LMR33620ADDA, the PG pin is an open-drain output that signals when the output voltage is within regulation (±3% of target). It pulls low during startup, undervoltage, overcurrent, thermal shutdown, or EN deactivation, and goes high after a 4 ms delay once regulation is achieved. With a 170 µs glitch filter, it ignores brief transients - enabling reliable system reset sequencing in PLCs, motor controllers, and embedded devices without spurious resets.

Can the LMR33620ADDA operate with an input voltage as low as 3.8 V?

Yes, the LMR33620ADDA is fully specified to operate down to 3.8 V input, enabling use with single-cell LiFePO₄ (3.2–3.6 V nominal) or low-voltage industrial buses. At this minimum input, it can regulate outputs as low as 1 V (e.g., 1 V @ 2 A) with appropriate inductor selection and layout. Its 75 ns minimum on-time and peak-current-mode architecture ensure stable operation even near dropout, where duty cycle approaches 98%.

How does thermal management differ between the LMR33620ADDA and the VQFN variant?

The LMR33620ADDA uses an 8-pin HSOIC package with PowerPAD™, achieving a junction-to-board thermal resistance (R_θJB) of 13.6°C/W on a 4-layer JEDEC board. In contrast, the VQFN variant (e.g., LMR33620ARNX) achieves 23.3°C/W - indicating superior heat transfer to the PCB. However, the HSOIC's larger body (5 mm × 4 mm) provides greater copper area for heatsinking, and its thermal pad is electrically tied to AGND, simplifying grounding. Both packages require solid thermal vias to inner ground planes.