Analog Devices Inc. LT8610IMSE#PBF

Overview

LT8610IMSE#PBF from Analog Devices (formerly Linear Technology) is a 42V, 2.5A synchronous step-down regulator with 2.5µA quiescent current in Burst Mode, 50ns minimum on-time, and internal compensation. It delivers regulated 3.3V/5V outputs from automotive or industrial 12V/24V supplies while maintaining <10mV_P-P output ripple and 96% peak efficiency at 1A/5V.

For engineers reviewing the LT8610IMSE#PBF datasheet, LT8610IMSE#PBF pinout, LT8610IMSE#PBF application, or LT8610IMSE#PBF equivalent, key selection factors include ultralow IQ for battery-backed systems, 200kHz–2.2MHz programmable switching frequency via RT resistor, ±9% power-good threshold accuracy, and thermal robustness enabled by exposed-pad MSOP-16 package.

Technical Context

The LT8610IMSE#PBF employs peak-current-mode control with internal compensation, enabling fast transient response and stable operation with small inductors. Its architecture integrates top and bottom NMOS power switches (120mΩ/65mΩ R_DS(ON)), a 0.97V reference, and frequency foldback during start-up or overcurrent to limit inductor current.

Burst Mode operation reduces input supply current to 2.5µA at no load while holding output ripple below 10mV_P-P; pulse-skipping mode (enabled via SYNC pin) trades higher IQ (~300µA) for deterministic timing alignment. EN/UV pin provides accurate 1.0V threshold with 40mV hysteresis for VIN undervoltage lockout or shutdown.

Key Specifications

Pinout & Package

LT8610IMSE#PBF is housed in a thermally enhanced 16-lead plastic MSOP package with exposed pad (Pin 17) soldered to PCB ground for θ_JA = 40°C/W and θ_JC(PAD) = 10°C/W. The exposed pad must be connected to PGND and input capacitor negative terminal for optimal thermal and EMI performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT8640SIV#PBF and MPQ4420AGL-AEC1-Z, the LT8610IMSE#PBF offers the lowest quiescent current (2.5µA) and greatest flexibility (RT/SYNC/BIAS/PG) for industrial and extended-battery-life applications, while trading off maximum current and automotive qualification.

Availability

LT8610IMSE#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, and portable medical sensor hubs requiring stable component supply, long-term lifecycle support, and guaranteed temperature-grade consistency.

Supply support for LT8610IMSE#PBF 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

Analog Devices acquired Linear Technology in 2017 and maintains its legacy of high-performance power management ICs with rigorous characterization and automotive-grade reliability.

The LT8610IMSE#PBF belongs to the Silent Switcher® family of high-efficiency, low-EMI monolithic buck regulators designed for noise-sensitive applications in automotive, industrial, and medical systems where ultralow IQ and thermal robustness are critical.

FAQ

What is the guaranteed operating junction temperature range for LT8610IMSE#PBF?

The LT8610IMSE#PBF is guaranteed over the full –40°C to +125°C junction temperature range. This I-grade rating ensures reliable operation in demanding industrial and automotive under-hood environments. The device incorporates overtemperature protection that activates above 150°C to safeguard against sustained overload, and its exposed-pad MSOP-16 package delivers θ_JC = 10°C/W for effective heat transfer to the PCB. Derating begins above 125°C per datasheet Note 2.

How does the BIAS pin improve efficiency in LT8610IMSE#PBF designs?

The BIAS pin on the LT8610IMSE#PBF allows internal circuitry to draw current from V_OUT instead of VIN when V_BIAS ≥ 3.1V, reducing input supply current and improving light-load efficiency. For 3.3V or 5V outputs, tying BIAS directly to V_OUT lowers total input current by ~8.5mA at 1A load (per datasheet Fig 29), which directly increases system efficiency - especially critical in battery-powered applications where every µA counts. Always bypass BIAS with a 1µF ceramic capacitor if not connected to V_OUT.

Can LT8610IMSE#PBF achieve 42V to 3.3V conversion without pulse skipping?

Yes, the LT8610IMSE#PBF can achieve 42V to 3.3V conversion without pulse skipping by selecting an appropriate switching frequency. With its 50ns minimum on-time, the maximum achievable duty cycle at 2MHz is ~10.5%, sufficient for 42V→3.3V (7.9%). Using Equation (4) from the datasheet, f_SW(MAX) ≈ 1.1MHz for this ratio - so setting RT for ≤1.1MHz (e.g., 18.2kΩ for 2.0MHz is too high; 33.2kΩ for 1.2MHz is acceptable) ensures continuous PWM operation. Frequency foldback remains active during start-up to prevent inductor saturation.

What is the purpose of the TR/SS pin on LT8610IMSE#PBF, and how is it configured?

On the LT8610IMSE#PBF, the TR/SS (Track/Soft-Start) pin controls output voltage ramp rate during startup and enables output voltage tracking. An internal 2.2µA current source pulls TR/SS up, so connecting a capacitor from TR/SS to GND programs the slew rate: dV_OUT/dt ≈ 2.2µA / C. When TR/SS voltage is below 0.97V, the FB pin is regulated to match TR/SS, enabling tracking of another supply. During fault or shutdown, an internal 230Ω MOSFET pulls TR/SS to GND - use a series resistor if driving from a low-impedance source.

How does the PG (Power Good) flag behave during input undervoltage or fault conditions on LT8610IMSE#PBF?

The PG pin on the LT8610IMSE#PBF is an open-drain output that remains low until V_OUT reaches and maintains ±9% of the programmed value, and no fault is present. Crucially, PG is valid whenever VIN > 3.4V - even if EN/UV is low (shutdown state). During input undervoltage (VIN < 3.4V), PG is undefined. Under fault conditions (e.g., overtemperature, output short), PG pulls low regardless of EN/UV state. The PG pull-down resistance is 680–2000Ω, requiring an external pull-up to a compatible voltage (e.g., V_OUT or INTVCC).