Analog Devices Inc. LTC3642EDD-5#TRPBF

Overview

LTC3642EDD-5#TRPBF from Analog Devices (formerly Linear Technology) is a high-voltage, synchronous step-down DC/DC converter with integrated high-side and low-side MOSFETs, delivering up to 50mA output current at a fixed 5V output. It operates from 4.5V to 45V input, tolerates 60V transients, and draws only 12µA quiescent current in Burst Mode® operation-enabling long battery life in industrial sensors and 4–20mA loop-powered transmitters.

For engineers reviewing the LTC3642EDD-5#TRPBF datasheet, LTC3642EDD-5#TRPBF pinout, LTC3642EDD-5#TRPBF application, or LTC3642EDD-5#TRPBF equivalent, key selection criteria include its 5V fixed output, programmable peak current limit (25–115mA), precise RUN pin threshold (1.21V rising), internal soft-start (0.75ms default), and compatibility with low-profile 3mm × 3mm DFN packaging for space-constrained embedded power rails.

Technical Context

The LTC3642EDD-5#TRPBF uses a hysteretic Burst Mode® control architecture with an internal 0.800V feedback reference and 5mV comparator hysteresis, enabling automatic transition between active switching and ultra-low-power sleep cycles. Its peak current mode control integrates a 1µA current source on ISET for resistor-programmable current limiting and a 5µA current source on SS for external soft-start timing.

Startup sequencing is governed by a precise RUN pin comparator (1.21V enable threshold, 110mV hysteresis) and HYST open-drain logic output for external hysteresis adjustment. The device features no-compensation design, 100% duty-cycle low-dropout operation, and internal overvoltage lockout (47V rising) and undervoltage lockout (3.80V rising) for robustness across harsh industrial input conditions.

Key Specifications

Pinout & Package

The LTC3642EDD-5#TRPBF is housed in an 8-lead, 3mm × 3mm plastic DFN package with exposed thermal pad (Pin 9), requiring soldering to PCB ground for optimal thermal performance (θ_JA = 43°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage, low-current step-down converter applications.

Compared with LT3652EMSE-5#TRPBF and TPS62130ARGTR, the LTC3642EDD-5#TRPBF uniquely combines 45V input rating, 60V surge tolerance, 12µA quiescent current, and programmable peak current in a 3mm × 3mm DFN-making it irreplaceable for ruggedized 5V regulation in industrial and automotive edge nodes.

Availability

LTC3642EDD-5#TRPBF is available at Aetrix Electronics and suitable for industrial control supplies, 4–20mA current loop transmitters, and battery-operated portable instruments requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC3642EDD-5#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC3642 product line was designed specifically for high-input-voltage, ultra-low-quiescent-current DC/DC conversion in space- and power-constrained industrial and automotive subsystems-emphasizing reliability, transient robustness, and minimal external component count.

FAQ

What is the maximum input voltage the LTC3642EDD-5#TRPBF can safely withstand?

The LTC3642EDD-5#TRPBF has an absolute maximum input rating of 60V and includes internal overvoltage lockout that disables switching above 47V (rising). This allows the device to survive automotive load-dump transients and industrial power surges without external protection components, while maintaining regulation from 4.5V to 45V during normal operation.

Does the LTC3642EDD-5#TRPBF require external compensation components?

No, the LTC3642EDD-5#TRPBF uses a proprietary hysteretic Burst Mode® architecture that requires no external compensation. Stability is inherent to the control scheme-only input capacitor (≥1µF), output capacitor (≥10µF), and inductor (e.g., 150µH) are needed for basic operation, significantly simplifying design and reducing bill-of-materials cost.

How is the peak current limit set on the LTC3642EDD-5#TRPBF?

The LTC3642EDD-5#TRPBF features a 1µA current source on the ISET pin (Pin 3). Connecting a resistor from ISET to GND sets the peak inductor current between 25mA (R = 0Ω) and 115mA (R = open). For example, a 500kΩ resistor yields ~55mA peak current, enabling optimization of inductor size and light-load efficiency without changing the IC.

Can the LTC3642EDD-5#TRPBF operate with input voltage close to its 5V output?

Yes, the LTC3642EDD-5#TRPBF supports 100% duty-cycle operation, allowing regulation down to VIN ≈ VOUT. At VIN = 5.5V, it maintains stable 5V output with full 50mA capability-making it ideal for brownout-tolerant designs in aging battery systems or low-headroom industrial supplies where other buck converters would drop out.

What is the purpose of the HYST pin on the LTC3642EDD-5#TRPBF?

The HYST pin (Pin 7) is an open-drain logic output that pulls low when the RUN pin voltage falls below 1.2V. It enables external hysteresis enhancement-for example, connecting HYST to the RUN divider network increases effective RUN threshold hysteresis beyond the internal 110mV, preventing oscillation during slow-rising input voltages in noisy industrial environments.