Analog Devices Inc. LT8494EFE#TRPBF

Overview

LT8494EFE#TRPBF from Analog Devices is a monolithic SEPIC/boost/flyback DC/DC controller IC featuring a 2A/70V NPN internal power switch, adjustable switching frequency (250kHz–1.5MHz), and ultra-low 7µA quiescent current in active operation. It supports dual supply inputs (VIN and BIAS), enabling efficient operation down to ~1V after startup and extending battery life in portable systems. Used in automotive ECU power supplies and industrial 5V/12V isolated converters.

For engineers reviewing the LT8494EFE#TRPBF datasheet, LT8494EFE#TRPBF pinout, LT8494EFE#TRPBF application, or LT8494EFE#TRPBF equivalent, key selection considerations include its FMEA-fault-tolerant TSSOP package, programmable UVLO via SWEN, low-ripple Burst Mode operation (<10mV ripple with 47µF output cap), and compatibility with SEPIC topologies requiring high input voltage tolerance up to 60V.

Technical Context

The LT8494EFE#TRPBF implements constant-frequency current-mode control with integrated slope compensation, supporting stable operation at duty cycles >50%. Its dual-supply architecture automatically selects between VIN and BIAS for NPN base drive, maintaining regulation even when VIN drops below 2.5V-enabling true single-cell Li-ion or supercapacitor backup operation.

It integrates frequency foldback (active when FB < 1V), soft-start (programmed via external capacitor on SS pin), and a precision power-good flag (PG) that asserts when VOUT reaches 92% of regulation. The internal 1.202V feedback reference exhibits ±2.2mV initial accuracy and <0.2%/V line regulation over 5V–32V input range.

Key Specifications

Pinout & Package

The LT8494EFE#TRPBF is housed in a 20-lead plastic TSSOP package with exposed pad (Pin 21 = GND), θ_JA = 38°C/W. All GND pins (14, 16, 21) and NC pins (4, 5, 6, 9, 11, 13, 15, 17, 19) must be correctly routed per FMEA fault-tolerance requirements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3789EFE#PBF and LT3958EFE#PBF, the LT8494EFE#TRPBF uniquely combines integrated 2A/70V NPN switching, 7µA quiescent current, and dual-supply (VIN/BIAS) operation-making it optimal for space-constrained, battery-sensitive SEPIC applications where fault tolerance and wide-input resilience are critical.

Availability

LT8494EFE#TRPBF is available at Aetrix Electronics and suitable for automotive ECU power, portable medical device supply, and industrial sensor node applications requiring stable component supply across extended temperature ranges (–40°C to 125°C).

Supply support for LT8494EFE#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.

The LT8494 product line delivers highly integrated, fault-resilient DC/DC controllers for demanding automotive, industrial, and portable applications where input voltage extremes, battery longevity, and functional safety are critical design constraints.

FAQ

What is the maximum input voltage supported by the LT8494EFE#TRPBF in SEPIC topology?

The LT8494EFE#TRPBF supports up to 60V input voltage in SEPIC configuration, as specified in Absolute Maximum Ratings and confirmed in Applications Information. This rating applies only to SEPIC; boost and flyback topologies are limited to 32V continuous input (with 60V ride-through capability during transients). Exceeding 60V on VIN or BIAS risks permanent damage.

How does the LT8494EFE#TRPBF achieve 7µA quiescent current, and under what conditions is it guaranteed?

The LT8494EFE#TRPBF achieves 7µA typical quiescent current from VIN when SWEN is high and VFB = 1.25V at TA = 25°C, per Electrical Characteristics table. This value is measured with VBIAS = 5V and VIN = 12V. Quiescent current drops to 0.3µA in shutdown (SWEN low). The 7µA spec is not guaranteed over temperature; the datasheet specifies 3.0µA (min) to 8.0µA (max) across –40°C to 125°C junction range for LT8494E grade.

Can the LT8494EFE#TRPBF operate with input voltage below 2.5V, and how does BIAS pin enable this?

Yes-the LT8494EFE#TRPBF can operate with VIN as low as ~1V after startup by drawing power from the BIAS pin. When VIN falls below 2.5V, the internal supply selector automatically switches NPN base drive to BIAS, allowing regulation to continue even if VIN drops to 1.3V (per PG functionality). This behavior is enabled only after successful startup and requires BIAS to be connected to a valid output or auxiliary rail ≥2.4V.

What is the purpose of the NC pins on the LT8494EFE#TRPBF TSSOP package, and how should they be handled?

The NC pins (4, 5, 6, 9, 11, 13, 15, 17, 19) on the LT8494EFE#TRPBF TSSOP package are not internally connected but must be left floating to preserve FMEA fault tolerance-specifically, to prevent output overvoltage during adjacent pin shorts. Soldering NC pins to ground or routing traces to them invalidates the fault-tolerant behavior documented in the Applications Information section and may cause unsafe output excursions.

Does the LT8494EFE#TRPBF support synchronization to an external clock, or is frequency only RT-programmable?

The LT8494EFE#TRPBF does not support external clock synchronization. Switching frequency is solely set by the resistor connected from RT (Pin 10) to GND, with values ranging from 41.2kΩ (1.5MHz) to 324kΩ (250kHz) per Table 1. No external sync pin exists; attempts to drive RT with a signal will disrupt oscillator operation and cause instability.