Texas Instruments LMR23615DRRR

Overview

LMR23615 from Texas Instruments is a synchronous step-down DC-DC converter delivering 1.5-A continuous output current with 4-V to 36-V input range, integrated high- and low-side MOSFETs (R_DS(on) = 160 mΩ / 95 mΩ), 60-ns minimum on-time, and internal compensation for simplified design. It powers industrial PLC CPU rails and HVAC control subsystems requiring wide-VIN regulation.

For engineers reviewing the LMR23615 datasheet, LMR23615 pinout, LMR23615 application, or LMR23615 equivalent, key selection considerations include PFM light-load efficiency (75 µA I_Q), frequency synchronization capability (200 kHz–2.2 MHz), hiccup-mode short-circuit protection, thermal shutdown (170°C threshold), and WSON-12 wettable flanks package for automated optical inspection.

Technical Context

The LMR23615 employs fixed-frequency peak-current-mode control with internal loop compensation, eliminating external compensation components. Its architecture integrates both power MOSFETs and an internal 4.1-V LDO for gate drive, enabling self-biased operation without auxiliary bias supplies.

It supports precision enable sequencing, soft-start into prebiased loads, and frequency foldback during dropout-extending regulation down to V_IN ≈ V_OUT + (I_OUT × R_{DS(on)_HS}) at high duty cycles. Synchronization via EN/SYNC pin accepts 2.8–5.5-V AC-coupled clock signals with ≥100-ns pulse width.

Key Specifications

Pinout & Package

LMR23615 is housed in a 3.00 mm × 3.00 mm, 12-pin WSON package with exposed thermal pad (PowerPAD™) and wettable flanks for solder-joint inspection. The package supports high-power density layouts with low thermal resistance (R_θJC(bot) = 3.4°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMR23625DRRR and TPS54332DDAR, the LMR23615DRRR offers optimal balance of low quiescent current, synchronization flexibility, and compact wettable-flank packaging-making it ideal for space-constrained, battery-aware, or EMI-sensitive industrial power nodes.

Availability

LMR23615DRRR is available at Aetrix Electronics and suitable for factory automation systems, building management controllers, and asset tracking devices requiring stable component supply across multi-year production cycles.

Supply support for LMR23615DRRR 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 industrial-grade DC-DC conversion.

The LMR236xx SIMPLE SWITCHER® product line targets rugged, easy-to-design power solutions for industrial, automotive, and IoT applications-emphasizing wide input range, integrated protection, and minimal external components.

FAQ

What is the minimum input voltage required for LMR23615DRRR to regulate a 5-V output at full 1.5-A load?

The LMR23615DRRR can maintain regulation at V_IN as low as ~5.6 V for 5-V output at 1.5-A load, enabled by frequency foldback that reduces switching frequency below 400 kHz when minimum off-time is reached. This behavior is confirmed in Figure 7-8 of the datasheet under dropout conditions with V_OUT = 5 V and initial f_SW = 2.1 MHz.

Does LMR23615DRRR support forced PWM mode, or is PFM the only light-load option?

The LMR23615DRRR does not support forced PWM mode; it operates exclusively in PFM mode at light loads to achieve 75-µA quiescent current. There is no pin or register to disable PFM. For applications requiring constant-frequency operation across all loads, consider alternatives like TPS54332DDAR or LM61480.

Can the EN/SYNC pin of LMR23615DRRR be used simultaneously for enable control and external clock synchronization?

No-the EN/SYNC pin cannot perform both functions concurrently. When used for synchronization, it must be AC-coupled with a series capacitor and biased via resistor divider; direct DC enable control is disabled during sync operation. For independent control, use the enable divider (RENT/RENB) and apply sync signal through the same node only when needed.

What is the recommended boot capacitor value for LMR23615DRRR, and why is capacitor quality critical?

Texas Instruments specifies a 100-nF to 470-nF high-quality ceramic capacitor (X7R or better, 16-V rating) between BOOT and SW pins for LMR23615DRRR. Low-ESR/ESL construction ensures reliable high-side gate drive during 60-ns minimum on-time operation; poor-quality or aged capacitors cause erratic switching or startup failure.

How does the LMR23615DRRR handle output short-circuit events, and what is the recovery behavior?

Upon output short-circuit detection, the LMR23615DRRR enters hiccup mode: it disables switching for 10 ms (T_OC), then attempts restart. If short persists, it repeats the cycle. This limits average power dissipation to safe levels and prevents thermal runaway-verified by 64 consecutive valley-current-limit trips triggering hiccup entry per Section 6.6.