Analog Devices Inc. LT3493EDCB#TRMPBF

Overview

LT3493EDCB#TRMPBF from Analog Devices (formerly Linear Technology) is a current-mode PWM step-down DC/DC converter with an integrated 1.75A bipolar NPN power switch, designed for automotive battery regulation and industrial control supplies. It operates from 3.6V to 36V input, delivers up to 1.2A output at fixed 3.3V or adjustable down to 780mV, and switches at 750kHz in a thermally enhanced 2mm × 3mm DFN package.

For engineers reviewing the LT3493EDCB#TRMPBF datasheet, LT3493EDCB#TRMPBF pinout, LT3493EDCB#TRMPBF application, or LT3493EDCB#TRMPBF equivalent, key selection criteria include its wide 3.6–36V input range, 750kHz fixed-frequency operation enabling compact magnetics, internal compensation, soft-start capability via SHDN pin, and robust short-circuit protection with <2μA shutdown current.

Technical Context

The LT3493EDCB#TRMPBF uses constant-frequency current-mode control with cycle-by-cycle current limiting and frequency foldback during overload. Its internal bipolar NPN switch requires a BOOST voltage ≥2.3V above SW to ensure low V_CE(SAT) (330mV at 1A), and the FB pin regulates to a precise 780mV reference with ±15mV tolerance over temperature.

Undervoltage lockout activates below ~3.4V, and thermal shutdown engages at T_J = 125°C. The device supports discontinuous conduction mode at light loads and maintains regulation up to 40V transient input, though minimum on-time (~120ns) limits stable continuous operation above VIN(MAX) ≈ 33V for 3.3V output.

Key Specifications

Pinout & Package

The LT3493EDCB#TRMPBF is housed in a thermally enhanced 6-lead (2mm × 3mm) plastic DFN package with exposed pad (Pin 7) that must be soldered to PCB ground for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3605EDE#PBF and TPS54202DRCT, the LT3493EDCB#TRMPBF offers superior transient immunity (40V), bipolar switch ruggedness for short-circuit survival, and guaranteed operation down to 3.6V - making it uniquely suitable for automotive and harsh industrial environments where input stability cannot be assumed.

Availability

LT3493EDCB#TRMPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial control supplies, and wall transformer regulation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LT3493EDCB#TRMPBF 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-branded power ICs.

The LT3493EDCB#TRMPBF belongs to Linear's high-voltage monolithic buck regulator family, engineered specifically for reliable DC/DC conversion in automotive, industrial, and telecom infrastructure where wide input range and transient robustness are mandatory.

FAQ

What is the maximum input voltage rating for the LT3493EDCB#TRMPBF?

The LT3493EDCB#TRMPBF has an absolute maximum input voltage rating of 40V, but its specified operating range is 3.6V to 36V. Operation at 36V–40V is permissible only for transient conditions such as load dump; continuous operation above 36V may increase output ripple due to minimum on-time limitation (~120ns) and should be verified per application requirements. The LT3493EDCB#TRMPBF datasheet specifies 36V as the maximum recommended continuous input voltage.

Does the LT3493EDCB#TRMPBF require an external BOOST capacitor and diode?

Yes, the LT3493EDCB#TRMPBF requires an external BOOST capacitor and fast-switching diode to generate a voltage higher than VIN for driving its internal bipolar NPN switch. A typical configuration uses a 0.1μF ceramic capacitor and a 1N4148 or BAT54 diode. The BOOST pin must be at least 2.3V above the SW pin for optimal efficiency; failure to implement this circuit results in excessive V_CE(SAT) and reduced output current capability in the LT3493EDCB#TRMPBF.

What is the feedback reference voltage of the LT3493EDCB#TRMPBF and how is output voltage set?

The LT3493EDCB#TRMPBF regulates its FB pin to a precise 780mV reference voltage with ±15mV tolerance over temperature. Output voltage is set using a resistor divider between VOUT and GND, with the FB pin connected to the divider tap. The formula is V_OUT = 0.78V × (1 + R1/R2), where R2 is typically 10kΩ. Using R2 ≤ 20kΩ minimizes error from FB bias current (≤150nA), ensuring accurate regulation in the LT3493EDCB#TRMPBF.

Can the LT3493EDCB#TRMPBF be used in battery-powered systems with deep discharge protection?

Yes, the LT3493EDCB#TRMPBF supports battery-powered systems through its <2μA shutdown current and undervoltage lockout (UVLO) threshold of ~3.4V. When the input drops below UVLO, the device disables switching and draws negligible current, preserving battery charge. In shutdown mode, the LT3493EDCB#TRMPBF disconnects the output, preventing reverse current flow. Its ability to regulate down to 3.6V input makes it compatible with single-cell Li-ion (2.7–4.2V) with appropriate pre-bias or multi-cell alkaline/NiMH configurations.

What thermal considerations apply to the LT3493EDCB#TRMPBF in its DFN package?

The LT3493EDCB#TRMPBF uses a 2mm × 3mm DFN package with an exposed thermal pad (Pin 7) that must be soldered to a PCB ground plane with ≥4 thermal vias for effective heat dissipation. With θ_JA = 64°C/W, the device can sustain 1.2A output at 12V input without forced air if ambient temperature remains ≤60°C. For higher ambient or continuous 1.2A loads, increasing copper area and via count reduces junction temperature; the LT3493EDCB#TRMPBF thermal shutdown triggers at 125°C to prevent damage.