Analog Devices Inc. LT3430IFE-1#PBF

Overview

LT3430IFE-1#PBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode buck switching regulator IC designed for industrial and automotive power conversion. It accepts 5.5V–60V input, delivers up to 2A output at 5V, integrates a 3A/0.1Ω NPN switch, operates at fixed 100kHz switching frequency, and features 1.22V feedback reference with cycle-by-cycle current limiting-used in battery chargers and distributed power systems.

For engineers reviewing the LT3430IFE-1#PBF datasheet, LT3430IFE-1#PBF pinout, LT3430IFE-1#PBF application, or LT3430IFE-1#PBF equivalent, key selection considerations include its 100kHz fixed-frequency operation (vs. 200kHz for LT3430), –40°C to 125°C industrial temperature rating, TSSOP-16 thermally enhanced package with exposed GND pad, and synchronous capability within 125kHz–250kHz range.

Technical Context

The LT3430IFE-1#PBF implements constant-frequency current-mode control using an internal oscillator, error amplifier (gm = 2000 µmho), and peak-current comparator referenced to the VC pin. Its architecture maintains stable 3A peak switch current across full duty cycle range via patented circuitry (US Patent #6498466), eliminating typical current-limit roll-off above 50% duty cycle.

It employs a BOOST pin-driven saturation scheme for the on-chip NPN switch, requiring an external boost capacitor and diode to achieve low 0.1Ω on-resistance. The BIAS pin enables efficiency optimization by sourcing internal bias current from the regulated output when V_OUT ≥ 3V, reducing input-referred quiescent current to 2.5mA typical.

Key Specifications

Pinout & Package

The LT3430IFE-1#PBF is housed in a 16-pin thermally enhanced TSSOP package (FE) with exposed GND pad (Pin 17) that must be soldered to PCB ground plane for thermal management (θ_JA = 45°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck regulator applications.

Compared with LTC3630EMSE-1#PBF and LM5164QPWPRQ1, the LT3430IFE-1#PBF offers unique fixed 100kHz operation with guaranteed 3A peak current across full duty cycle and integrated foldback protection-making it optimal for cost-sensitive, thermally demanding industrial power supplies where predictable EMI and robust short-circuit behavior are prioritized over ultra-small size or automotive qualification.

Availability

LT3430IFE-1#PBF is available at Aetrix Electronics and suitable for industrial power supplies, automotive battery chargers, and distributed power systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LT3430IFE-1#PBF 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 support for legacy Linear power products including the LT3430 family.

The LT3430IFE-1#PBF belongs to Linear's high-voltage monolithic buck regulator product line, engineered for rugged industrial and automotive power conversion where wide input range, thermal resilience, and predictable fault behavior are essential.

FAQ

What is the difference between LT3430IFE-1#PBF and LT3430IFE#PBF?

The LT3430IFE-1#PBF operates at a fixed 100kHz switching frequency with a SYNC range of 125kHz–250kHz, while the LT3430IFE#PBF runs at 200kHz with SYNC range 228kHz–700kHz. Both share identical pinout, package, temperature rating (–40°C to 125°C), and electrical specs except frequency-related parameters. The -1 suffix denotes the lower-frequency variant optimized for higher-inductance, lower-EMI designs.

Does LT3430IFE-1#PBF require an external boost capacitor?

Yes, the LT3430IFE-1#PBF requires an external boost capacitor and diode connected to the BOOST pin to drive the internal NPN switch into saturation. Without it, switch on-resistance rises significantly above the specified 0.1Ω, increasing conduction loss and thermal stress. Typical implementation uses a 100V ceramic capacitor and fast-switching diode like MMSD914.

Can LT3430IFE-1#PBF be synchronized to a 150kHz clock?

Yes, the LT3430IFE-1#PBF supports external synchronization from 125kHz to 250kHz, so a 150kHz clock falls within its valid SYNC range. The SYNC pin is logic-level compatible (10–90% duty cycle), requires no level-shifting, and maintains regulation stability across the full range without additional components.

What is the minimum input voltage for LT3430IFE-1#PBF to start regulation?

The LT3430IFE-1#PBF has a guaranteed minimum input voltage of 5.5V for normal operation. Below this, internal bias lines may not regulate properly. However, startup voltage depends on output voltage and load: for a 5V output, minimum start voltage is ~7.5V (per datasheet note), rising with higher V_OUT or heavier loads due to BOOST pin requirements.

How does the FB pin foldback protection work in LT3430IFE-1#PBF?

When the FB pin voltage drops below 0.8V (e.g., during short-circuit or start-up), the LT3430IFE-1#PBF reduces switching frequency by ~5:1 to limit power dissipation. If FB falls below 0.6V, it further reduces peak switch current limit and disables SYNC. This dual-foldback mechanism protects the IC, inductor, and catch diode without external circuitry-fully implemented within the LT3430IFE-1#PBF.