Analog Devices Inc. LT8365JMSE#PBF

Overview

LT8365JMSE#PBF from Analog Devices is a current-mode DC/DC converter IC with a 1.5A, 150V internal power switch, supporting boost, SEPIC, and inverting topologies across a 2.8V–60V input range. It delivers ultralow 9µA quiescent current in Burst Mode, maintains <15mV output ripple, and operates up to 500kHz with external frequency programming - enabling high-efficiency negative-output (-250V) or high-voltage positive-output power supplies for medical imaging and industrial sensing.

For engineers reviewing the LT8365JMSE#PBF datasheet, LT8365JMSE#PBF pinout, LT8365JMSE#PBF application, or LT8365JMSE#PBF equivalent, key selection criteria include its single-feedback-pin topology flexibility, AEC-Q100 qualification (J-grade), 150V switch rating, programmable soft-start, and spread-spectrum EMI reduction - all in a thermally enhanced 16-lead MSOP package with 4 pins removed for HV spacing.

Technical Context

The LT8365JMSE#PBF implements fixed-frequency current-mode control with dual error amplifiers (A1/A2) that auto-select based on FBX polarity: +1.60V reference for positive outputs (boost/SEPIC), –0.80V reference for negative outputs (inverting). Its unique single FBX pin eliminates topology-specific feedback networks while maintaining precise regulation across configurations.

Switching behavior is dynamically managed via the SYNC/MODE pin, enabling five distinct operating modes: Burst Mode (<9µA IQ), pulse-skipping, external clock synchronization (100–500kHz), spread-spectrum modulation (±20% Δf/fOSC), or hybrid Burst+SSFM. The BIAS pin supports dual-input operation (4.4V ≤ BIAS ≤ VIN) to offload INTVCC current from VIN, improving full-load efficiency by reducing input-side conduction loss.

Key Specifications

Pinout & Package

LT8365JMSE#PBF uses a thermally enhanced 16-lead MSOP package (MSE16 variation) with pins 2, 3, 4, and 15 removed to increase high-voltage spacing between SW and adjacent terminals. The exposed pad (Pin 17) is PGND/GND and must be soldered to a solid PCB ground plane for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage DC/DC converter applications.

Compared with LT3757AIMSE#PBF and LTC3789EMSE#PBF, the LT8365JMSE#PBF uniquely integrates a 150V/1.5A switch with topology-agnostic feedback and SSFM in one MSE package - reducing component count for non-isolated high-voltage supplies while meeting automotive and medical EMI requirements without external circuitry.

Availability

LT8365JMSE#PBF is available at Aetrix Electronics and suitable for medical diagnostic equipment, automotive ADAS camera modules, and industrial PLC analog input stages requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.

Supply support for LT8365JMSE#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.

The LT8365JMSE#PBF belongs to Analog Devices' Power by Linear™ family of high-voltage DC/DC converters, designed specifically for space-constrained, high-reliability applications demanding wide input range, ultralow IQ, and flexible topology support - including medical imaging, automotive sensing, and test equipment.

FAQ

What is the maximum output voltage achievable with the LT8365JMSE#PBF in inverting configuration?

The LT8365JMSE#PBF supports inverting operation with a 150V-rated internal switch, enabling output voltages up to –250V as demonstrated in the datasheet's typical application. This capability relies on proper selection of external components - particularly the Schottky diode (e.g., DFLS1150) and inductor (e.g., WE-PD 74437324100) - and adherence to minimum off-time and duty cycle constraints. The LT8365JMSE#PBF itself does not limit output voltage beyond its 150V switch rating; system-level insulation and component voltage ratings determine the practical maximum.

How does the LT8365JMSE#PBF achieve 9µA quiescent current, and what conditions must be met?

The LT8365JMSE#PBF achieves 9µA quiescent current only in Burst Mode operation, which activates when the SYNC/MODE pin is held below 0.14V (e.g., tied to GND). This mode disables switching during light loads and enters deep sleep between brief current pulses, minimizing VIN current draw. To sustain this ultra-low IQ, the feedback resistor divider current must be minimized (e.g., using ≥500kΩ total resistance), and all output leakage paths - especially Schottky diode reverse current - must be tightly controlled. The LT8365JMSE#PBF specification assumes these conditions per the datasheet's Electrical Characteristics table.

Can the LT8365JMSE#PBF be synchronized to an external clock, and what are the valid input specifications?

Yes, the LT8365JMSE#PBF can be synchronized to an external clock via the SYNC/MODE pin. Valid input signals must be square waves with 20%–80% duty cycle, valley voltage <0.4V, and peak voltage >1.7V (up to 6V absolute max). Synchronization is supported across 100kHz–500kHz, and the internal RT resistor should be selected to set the nominal fSW at or below the lowest expected sync frequency. When synchronized, the LT8365JMSE#PBF operates in pulse-skipping mode rather than Burst Mode to maintain clock alignment.

What is the purpose of the BIAS pin on the LT8365JMSE#PBF, and how does it improve efficiency?

The BIAS pin on the LT8365JMSE#PBF supplies the internal INTVCC regulator when 4.4V ≤ BIAS ≤ VIN, diverting ~1.2mA of bias current away from the main VIN rail. This reduces conduction losses in the input path - especially beneficial in SEPIC or boost applications where VIN may be significantly lower than VOUT (e.g., 12V input → 48V output). Efficiency gains are most pronounced at full load; if unused, the BIAS pin must be tied to GND. The LT8365JMSE#PBF automatically selects between VIN and BIAS sources based on voltage thresholds, requiring no external control logic.

Is the LT8365JMSE#PBF pin-compatible with other grades in the LT8365 family, such as the LT8365EMSE#PBF?

Yes, the LT8365JMSE#PBF is pin-compatible and footprint-compatible with all variants in the LT8365 family (E-, J-, and H-grade), including LT8365EMSE#PBF and LT8365HMSE#PBF. All share identical pinout, package dimensions (16-lead MSOP with 4 pins removed), and electrical interface. The only differences are guaranteed operating temperature ranges (–40°C to +125°C for E-grade, –40°C to +150°C for J/H-grade) and associated screening/test conditions. No PCB redesign is needed when upgrading from E- to J-grade for higher ambient temperature operation.