Analog Devices Inc. LT3759HMSE#PBF

Overview

LT3759HMSE#PBF from Analog Devices (formerly Linear Technology) is a wide-input, current-mode DC/DC controller capable of regulating positive or negative output voltages in boost, SEPIC, or inverting configurations. It drives an external N-channel MOSFET, features 50 mV SENSE threshold, programmable 100 kHz–1 MHz switching frequency, and operates from 1.6 V to 42 V input - ideal for automotive 12 V post-regulation and industrial distributed supplies.

For engineers reviewing the LT3759HMSE#PBF datasheet, LT3759HMSE#PBF pinout, LT3759HMSE#PBF application, or LT3759HMSE#PBF equivalent, key selection considerations include its dual-polarity feedback architecture (1.6 V / –0.8 V FBX regulation), PGOOD status reporting, INTVCC LDO sourcing options (VIN or DRIVE), thermal grade (–40°C to 150°C), and exposed-pad MSOP-12 package thermal performance.

Technical Context

The LT3759HMSE#PBF implements fixed-frequency current-mode control with dual error amplifiers-one for positive output regulation (1.6 V reference), one for negative (–0.8 V reference)-selected automatically based on topology. Its SENSE pin monitors switch current via an external sense resistor with 46–54 mV threshold, while VC provides compensation node access for loop stability.

It integrates two independent LDOs: DRIVE LDO (4.6–4.9 V output, sourced from DRIVE pin) and VIN LDO (3.6–3.9 V, sourced from VIN), both feeding INTVCC. The PGOOD pin asserts open-collector low when FBX is within ±5% of regulation voltage and INTVCC > 2.7 V, enabling system-level power sequencing.

Key Specifications

Pinout & Package

The LT3759HMSE#PBF is housed in a 12-lead plastic MSOP package with exposed pad (Pin 13), which must be soldered to PCB ground for thermal and electrical integrity. θ_JA = 35–40°C/W with proper copper plane layout.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DC/DC controller applications.

Compared with LTC3789EMSE#PBF and TPS40210DGQ, the LT3759HMSE#PBF uniquely supports inverting topology with single-pin polarity selection and integrated PGOOD - making it optimal for space-constrained, dual-rail, or automotive post-regulator designs requiring guaranteed thermal robustness to 150°C.

Availability

LT3759HMSE#PBF is available at Aetrix Electronics and suitable for automotive post-regulators, industrial distributed supplies, portable equipment power, and datacom mid-board supplies requiring stable component supply, extended temperature operation, and long-term lifecycle continuity.

Supply support for LT3759HMSE#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 full product support, documentation, and manufacturing continuity for all Linear parts including the LT3759 family.

The LT3759 product line delivers high-voltage, wide-input DC/DC controllers optimized for automotive, industrial, and telecom applications where input transients, thermal stress, and topology flexibility are critical design constraints.

FAQ

What is the maximum operating junction temperature for LT3759HMSE#PBF?

The LT3759HMSE#PBF is specified for operation from –40°C to +150°C junction temperature. This H-grade qualification is guaranteed across the full range and distinguishes it from E- and I-grade variants (–40°C to +125°C). Thermal derating applies above 125°C per manufacturer guidelines, and proper PCB copper area under the exposed pad is required to achieve θ_JA ≤ 40°C/W.

How does the LT3759HMSE#PBF select between positive and negative output regulation?

The LT3759HMSE#PBF automatically selects regulation polarity based on the FBX pin voltage: if FBX is pulled above GND (e.g., via resistor divider from positive VOUT), the 1.6 V positive reference activates; if FBX is pulled below GND (e.g., from negative VOUT), the –0.8 V negative reference engages. No external configuration pins or mode selection is needed - the internal dual-error-amplifier architecture handles this transparently.

Can LT3759HMSE#PBF synchronize to an external clock, and what are the requirements?

Yes, the LT3759HMSE#PBF supports synchronization via the SYNC pin. The external clock must have ≥200 ns pulse width and be applied to SYNC while INTVCC > 2.7 V. To ensure reliable locking, the RT resistor must be selected to program an internal oscillator frequency ~20% slower than the SYNC frequency. If unused, SYNC must be tied to GND - leaving it floating may cause erratic operation.

What is the purpose of the two LDOs (VIN and DRIVE) in LT3759HMSE#PBF?

The LT3759HMSE#PBF integrates two independent LDOs to power INTVCC: the VIN LDO (3.6–3.9 V output, sourced from VIN) and DRIVE LDO (4.6–4.9 V output, sourced from DRIVE). This dual-source architecture allows INTVCC to be powered from either rail - e.g., DRIVE can be connected to a clean, quasi-regulated converter output to improve gate drive efficiency and reduce thermal load on the IC when VIN is high.

Does LT3759HMSE#PBF support short-circuit protection, and how does it behave?

Yes, the LT3759HMSE#PBF provides short-circuit protection via frequency foldback and current limiting. When output voltage collapses (e.g., during short), FBX approaches GND, triggering frequency foldback to reduce switching frequency and maintain current limit compliance. Simultaneously, the 50 mV SENSE threshold enforces hard current limiting. PGOOD deasserts immediately, and soft-start restarts once fault clears - preventing thermal runaway and component stress.