Analog Devices Inc. LT3782AEFE

Overview

LT3782AEFE from Analog Devices (formerly Linear Technology) is a current-mode, 2-phase step-up DC/DC controller IC designed for high-efficiency industrial and telecom boost converters. It delivers up to 50V/4A output from 10V–36V input, operates at 150kHz–500kHz switching frequency, features dual 10V/4A gate drivers, and supports programmable slope compensation and duty cycle clamp. It is used in interleaved isolated power supplies requiring reduced input/output capacitance.

For engineers reviewing the LT3782AEFE datasheet, LT3782AEFE pinout, LT3782AEFE application, or LT3782AEFE equivalent, key selection criteria include its 2-phase current-mode control architecture, ±10mV current sense mismatch tolerance, 28-lead TSSOP thermal performance (θ_JA = 30°C/W), and synchronous gate signal timing with programmable falling-edge delay for external MOSFET drivers.

Technical Context

The LT3782AEFE implements a dual-channel, constant-frequency current-mode PWM architecture with internal 180° phase interleaving. Its transconductance error amplifier (200–370 µmho) regulates output voltage via FB pin feedback against a 2.44V reference, while two independent current-sense amplifiers (63mV threshold per channel, ±10mV mismatch) control peak inductor current per phase.

It integrates dual high-current gate drivers (BGATE1/BGATE2: 4A peak sink/source, 10.2–11.7V bias), programmable oscillator (RSET-based, 150–500kHz), and dedicated control pins including DELAY (for SGATE-to-BGATE dead-time adjustment), DCL (duty cycle clamp), and SLOPE (external slope compensation). The IC requires external synchronous drivers for top-FET control via SGATE1/SGATE2 outputs.

Key Specifications

Pinout & Package

LT3782AEFE is housed in a thermally enhanced 28-lead plastic TSSOP (FE package) with exposed pad (Pin 29) soldered to PCB ground for optimal thermal performance (θ_JA = 30°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2-phase boost controller applications.

Compared with LTC3780EFE and LT3758AIFE, the LT3782AEFE uniquely provides true 2-phase interleaving, dual SGATE outputs for synchronous rectification, and tighter current sense matching - making it the only option among the three for high-efficiency, low-EMI 50V/4A telecom and industrial boost designs.

Availability

LT3782AEFE is available at Aetrix Electronics and suitable for telecom infrastructure, industrial equipment, and interleaved isolated power supply designs requiring stable component supply, long-term lifecycle support, and guaranteed thermal performance in extended temperature ranges.

Supply support for LT3782AEFE 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 the LT3782A family.

The LT3782A product line was engineered specifically for high-efficiency, high-current, 2-phase boost conversion in space-constrained industrial and telecom applications where input/output ripple reduction and thermal management are critical.

FAQ

What is the maximum output voltage and current supported by the LT3782AEFE?

The LT3782AEFE is rated for 50V output voltage and 4A output current in typical 2-phase boost configurations. This rating assumes proper thermal management (exposed pad soldered to ground plane), appropriate external MOSFET selection (e.g., Si7852DP-T1-E3), and input voltage within the 10V–36V range. The IC itself does not regulate current directly but enforces per-phase current limits via 63mV sense thresholds; total output capability depends on layout, inductors, and output capacitance.

Does the LT3782AEFE support synchronization to an external clock?

Yes, the LT3782AEFE supports external synchronization via the SYNC pin (Pin 5). A TTL-compatible pulse (0.8V–2V threshold, 10%–70% duty cycle) applied to SYNC forces the internal oscillator to lock to half the sync frequency. For example, a 400kHz sync signal results in 200kHz switching frequency. The IC includes a 200ns one-shot timer to accommodate narrow pulses, and the SYNC pin may be left floating if synchronization is unused.

How does the DELAY pin function in the LT3782AEFE?

The DELAY pin (Pin 6) programs the dead time between SGATE turn-off and BGATE turn-on to prevent cross-conduction in synchronous rectifier designs. When tied directly to RSET, it provides ~100ns delay; a resistor divider from RSET to GND adjusts V_DELAY to extend delay up to 500ns. This timing control is essential when using external high-side drivers, as propagation delays vary across driver ICs and must be compensated to avoid shoot-through.

What is the purpose of the SLOPE pin on the LT3782AEFE?

The SLOPE pin (Pin 10) allows external adjustment of the internal current-mode PWM slope compensation. Connecting a resistor from SLOPE to GND increases the compensation ramp, improving noise immunity in high-duty-cycle or high-noise applications (e.g., >75% duty cycle or high dv/dt environments). Smaller resistor values increase compensation; minimum allowed value is R_RSET/2. This feature stabilizes operation where inherent slope is insufficient to prevent subharmonic oscillation.

Can the LT3782AEFE operate with input voltages below 10V?

No - the LT3782AEFE has a specified minimum input voltage of 10V per Absolute Maximum Ratings and Electrical Characteristics tables. Operation below 10V violates the guaranteed operating range and may result in unstable regulation, insufficient gate drive (V_GBIAS drops below 10.2V), or failure to initiate soft-start. For 6V–40V input range, the base LT3782A (not the 'A' variant) is specified, but LT3782AEFE is optimized for tighter current sense matching and industrial temperature grade only above 10V.