Texas Instruments LMR36500F3RPER

Overview

LMR36500F3RPER from Texas Instruments is a 3-V to 65-V, 50-mA synchronous buck DC/DC converter in a 2-mm × 2-mm HotRod™ VQFN-HR package, featuring fixed 3.3-V output, FPWM light-load operation, adjustable 200 kHz–2.2 MHz switching frequency via RT pin, and –40°C to +150°C junction temperature rating. It delivers >80% peak efficiency at 1 MHz for industrial field transmitters and process sensors.

For engineers reviewing the LMR36500F3RPER datasheet, LMR36500F3RPER pinout, LMR36500F3RPER application, or LMR36500F3RPER equivalent, key selection considerations include its 70-V input transient capability, precision EN/UVLO with 0.35-V hysteresis, PGOOD flag with 25-µs glitch filter and 1.96-ms activation delay, and internal compensation enabling minimal external output capacitance.

Technical Context

The LMR36500F3RPER uses peak current mode control with internal compensation, eliminating need for external loop compensation components. Its FPWM light-load mode ensures consistent switching frequency down to zero load, critical for EMI-sensitive applications like fire safety detectors and portable earbuds.

It integrates precision enable logic (VEN-VOUT = 1.263 V typ, VEN-HYST = 0.35 V), thermal shutdown (TSD-R = 168°C typ), and robust protection including high-side MOSFET R_DS(on) = 5 Ω and low-side R_DS(on) = 3.5 Ω - all validated across –40°C to +150°C operating range.

Key Specifications

Pinout & Package

VQFN-HR (RPE) package: 9-pin, 2.0 mm × 2.0 mm, thermally enhanced with exposed pad and corner anchor pins for mechanical reliability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMR36500F3RPER, LMR36500P3RPE trades EMI predictability for slightly lower no-load current, while LMR36503RPER retains identical footprint and control features but scales output current 6× - enabling direct upgrade path in space-constrained industrial designs.

Availability

LMR36500F3RPER is available at Aetrix Electronics and suitable for factory automation sensors, building fire safety detectors, and portable garden tools requiring stable component supply, long-term lifecycle support, and automotive-grade reliability under thermal stress.

Supply support for LMR36500F3RPER 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 delivering analog and embedded processing solutions, with decades of expertise in power management ICs for industrial, automotive, and consumer markets.

The LMR36500F3RPER belongs to TI's LMR365xx family of wide-input, low-I_Q buck converters designed specifically for rugged, space-constrained industrial power rails - emphasizing thermal resilience, EMI robustness, and minimal external component count.

FAQ

What is the maximum input voltage transient the LMR36500F3RPER can survive?

The LMR36500F3RPER is rated for input transients up to 70 V, exceeding its 65-V maximum operating input voltage. This rating is validated per absolute maximum specifications and enables reliable operation in industrial environments with inductive load switching or lightning-induced surges. The device remains functional after such events without latch-up or parametric shift, provided duration stays within safe energy limits defined by external input capacitance and source impedance.

Does the LMR36500F3RPER require external compensation components?

No, the LMR36500F3RPER uses an internally compensated peak current mode control architecture. This eliminates the need for external Type-II or Type-III compensation networks, reducing bill-of-materials cost and PCB area. Stability is maintained across the full 3.3-V output range with as little as 10 µF of ceramic output capacitance, verified over –40°C to +150°C and 3.6–65 V input conditions.

How does the PGOOD function behave during startup and fault conditions in the LMR36500F3RPER?

In the LMR36500F3RPER, PGOOD asserts high 1.96 ms after soft-start completion (t_{PGOOD_ACT}), with a built-in 25-µs glitch filter preventing false trips from line/load transients. It goes low during EN deactivation, thermal shutdown, current limit, or output undervoltage/overvoltage. PGOOD remains valid down to V_PG-VALID = 0.9 V (min), allowing monitoring even during brownout conditions - a behavior confirmed in Section 6.5 of the LMR36500F3RPER datasheet.

Can the LMR36500F3RPER be synchronized to an external clock?

No, the LMR36500F3RPER does not support external clock synchronization. It operates with either fixed-frequency FPWM mode (default) or RT-pin programmable internal oscillator (200 kHz–2.2 MHz). Synchronization capability is reserved for other variants in the family, such as the MODE/SYNC-pin versions - not implemented in the LMR36500F3RPER orderable part number.

What is the thermal shutdown threshold of the LMR36500F3RPER?

The LMR36500F3RPER triggers thermal shutdown at a junction temperature of 168°C (typical), with hysteresis of 10°C (typical). Once tripped, the device halts switching and remains off until junction temperature falls to approximately 158°C. This behavior is fully characterized across process and temperature, and the thermal protection circuit is integrated into the die - no external components are required for implementation.