Analog Devices Inc. LTC3632EDD#TRPBF

Overview

LTC3632EDD#TRPBF from Analog Devices (formerly Linear Technology) is a high-voltage, synchronous step-down DC/DC converter IC with integrated high-side and low-side MOSFETs, delivering up to 20mA output current from a 4.5V–50V input. It features 12µA no-load quiescent current, 0.8V ±1% feedback reference, and programmable peak current limit (10–50mA), making it ideal for industrial control supplies and battery-operated instrumentation requiring ultra-low power standby.

For engineers reviewing the LTC3632EDD#TRPBF datasheet, LTC3632EDD#TRPBF pinout, LTC3632EDD#TRPBF application, or LTC3632EDD#TRPBF equivalent, key selection criteria include input voltage range (4.5–50V), output current capability (20mA), thermal performance in the 3mm × 3mm DFN package, and Burst Mode® operation for sub-15µA sleep current in low-power sensor nodes and loop-powered systems.

Technical Context

The LTC3632EDD#TRPBF implements a hysteretic Burst Mode® control architecture with internal P-channel high-side and N-channel low-side synchronous switches. Its feedback comparator compares VFB against a precise 0.800V reference with 5mV hysteresis, enabling automatic transition between burst cycles and deep-sleep mode.

Start-up is managed via a precision RUN pin threshold (1.21V rising, 1.10V falling) with adjustable hysteresis using the HYST open-drain output, while soft-start is implemented either internally (0.75ms) or externally via SS pin current sourcing (5.5µA). Peak inductor current is set by a resistor from ISET to GND, scaling linearly from 10mA (ISET = GND) to 50mA (ISET floating).

Key Specifications

Pinout & Package

The LTC3632EDD#TRPBF is housed in an 8-lead, 3mm × 3mm plastic DFN package with exposed pad (Pin 9), which must be soldered to PCB ground for thermal and electrical integrity. Thermal resistance is θ_JA = 43°C/W and θ_JC = 3°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3631EDD#TRPBF and TPS62125DSGR, the LTC3632EDD#TRPBF uniquely combines 50V input tolerance, programmable current limiting, and 12µA quiescent current in a thermally enhanced DFN - making it the sole option for ruggedized, ultra-low-power 4–20mA loop and industrial sensor supplies.

Availability

LTC3632EDD#TRPBF is available at Aetrix Electronics and suitable for industrial control supplies, 4–20mA current loops, and portable instrumentation requiring stable component supply across extended temperature ranges (–40°C to 125°C).

Supply support for LTC3632EDD#TRPBF 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 high-reliability analog and power management product lines with rigorous qualification and long-term support.

The LTC3632EDD#TRPBF belongs to Linear's high-voltage monolithic DC/DC converter family, designed specifically for industrial, automotive, and instrumentation applications demanding wide input range, ultra-low quiescent current, and robust transient protection.

FAQ

What is the maximum input voltage the LTC3632EDD#TRPBF can withstand without damage?

The LTC3632EDD#TRPBF has an absolute maximum VIN rating of 60V and includes internal overvoltage lockout that disables switching above 54V (rising). This allows the device to survive 60V surges - such as automotive load dump or industrial transients - while maintaining safe operation within its 4.5V–50V functional range. The 60V rating is sustained only during fault conditions; continuous operation must remain ≤50V.

Can the LTC3632EDD#TRPBF regulate output voltages below 0.8V?

No, the LTC3632EDD#TRPBF cannot regulate output voltages below 0.8V because its internal feedback comparator is referenced to a fixed 0.800V ±1% precision bandgap. The minimum regulated output is defined by V_OUT = 0.8V × (1 + R1/R2), so setting R2 = ∞ (open) yields V_OUT = 0.8V. Lower outputs require an external reference or a different regulator architecture.

How does the ISET pin affect efficiency at light loads for the LTC3632EDD#TRPBF?

The ISET pin on the LTC3632EDD#TRPBF sets the peak inductor current, which directly impacts light-load efficiency. Reducing peak current (e.g., to 10mA via ISET-to-GND) lowers switching losses and allows smaller magnetics, improving efficiency below 5mA. However, excessively low peak current may increase output ripple and reduce transient response - optimal setting balances ripple, size, and sub-mA efficiency.

Is the exposed thermal pad (Pin 9) of the LTC3632EDD#TRPBF electrically connected to ground?

Yes, the exposed thermal pad (Pin 9) of the LTC3632EDD#TRPBF is internally connected to GND and must be soldered to a PCB ground plane. This connection is mandatory for both thermal performance (θ_JC = 3°C/W) and electrical stability - floating or unconnected pads cause elevated junction temperatures, reduced efficiency, and potential regulation failure under load.

Does the LTC3632EDD#TRPBF support 100% duty cycle operation, and what is its practical benefit?

Yes, the LTC3632EDD#TRPBF supports 100% duty cycle operation, meaning it can maintain regulation even when V_IN ≈ V_OUT. This is critical in battery-powered systems nearing end-of-life or in 4–20mA loop-powered transmitters where input voltage sags close to the output level. Unlike many buck converters that drop out below V_IN = V_OUT + dropout voltage, the LTC3632EDD#TRPBF sustains regulation down to V_IN = V_OUT, maximizing usable battery capacity.