Analog Devices Inc. LT1534IS-1#PBF

Overview

LT1534IS-1#PBF from Analog Devices (formerly Linear Technology) is an ultralow-noise, 2A current-mode switching regulator optimized for low-EMI boost topologies. It features independently programmable voltage and current slew rates (11 V/µs rising, 14.5 V/µs falling), 2.7V–23V input range, ±2.5V dual-polarity feedback capability, and 20kHz–250kHz adjustable oscillator frequency. It is used in precision instrumentation systems requiring clean power delivery with minimal conducted/radiated noise.

For engineers reviewing the LT1534IS-1#PBF datasheet, LT1534IS-1#PBF pinout, LT1534IS-1#PBF application, or LT1534IS-1#PBF equivalent, key selection considerations include slew-controlled EMI reduction, negative/positive output regulation support, thermal shutdown and cycle-by-cycle current limiting, SO-16 package thermal performance (θ_JA = 50°C/W), and synchronization capability for harmonic placement.

Technical Context

The LT1534IS-1#PBF implements a current-mode control architecture with internal slope compensation, enabling stable operation up to 91% duty cycle. Its dual error amplifiers - one referenced to +1.25V (FB) and another to –2.5V (NFB) with –0.5 gain - allow simultaneous regulation of positive and negative outputs without external op-amps.

Slew control is achieved via two independent analog loops: RVSL sets collector voltage dV/dt (220/RVSL kΩ V/µs), while RCSL sets emitter current dI/dt (33/RCSL kΩ A/µs). The VC pin serves as error amplifier output, current limit threshold, and soft-start node - integrating loop compensation, protection, and transient response tuning.

Key Specifications

Pinout & Package

LT1534IS-1#PBF is housed in a 16-pin narrow SOIC package (S package) with four corner pins fused to the die attach paddle for enhanced thermal dissipation (θ_JA = 50°C/W). The package requires connection of pins 1, 8, 9, and 16 to expanded PCB lands for proper heat sinking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3891EFE#PBF and TPS61088RHLR, the LT1534IS-1#PBF uniquely delivers programmable slew rates, dual-polarity feedback, and oscillator synchronization - making it the only option among the three capable of meeting stringent radiated emissions requirements in precision analog systems without external filtering.

Availability

LT1534IS-1#PBF is available at Aetrix Electronics and suitable for precision instrumentation systems, isolated industrial power supplies, medical diagnostic devices, and wireless infrastructure equipment requiring stable component supply across long production lifecycles.

Supply support for LT1534IS-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) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.

The LT1534IS-1#PBF belongs to Linear's legacy ultralow-noise switching regulator product line, specifically engineered for EMI-sensitive applications where traditional switchers compromise signal integrity - such as laboratory-grade instrumentation and clinical-grade medical electronics.

FAQ

What is the primary function of the LT1534IS-1#PBF in a power supply design?

The LT1534IS-1#PBF functions as an ultralow-noise, 2A current-mode switching regulator optimized for boost topologies. Its core purpose is to deliver clean, regulated output voltage - either positive (via FB pin) or negative (via NFB pin) - while minimizing conducted and radiated EMI through user-programmable voltage and current slew rates. In every LT1534IS-1#PBF application, this dual-slew control directly reduces high-frequency harmonic content by up to 40dB compared to standard switchers.

How does the LT1534IS-1#PBF support dual-polarity output regulation?

The LT1534IS-1#PBF supports dual-polarity regulation using two independent feedback paths: the FB pin references a +1.25V internal bandgap for positive output control, while the NFB pin references a –2.5V node (with –0.5 gain) for negative output control. When both pins are used, the LT1534IS-1#PBF prevents either rail from exceeding its setpoint - enabling single-chip ±5V or ±12V generation without external op-amps or level shifters. This capability is intrinsic to the LT1534IS-1#PBF silicon architecture.

What thermal considerations apply to the LT1534IS-1#PBF in the SO-16 package?

The LT1534IS-1#PBF in the 16-pin narrow SO package (S package) has a specified θ_JA of 50°C/W due to fused corner pins connected to the die attach paddle. To maintain safe junction temperature, these four pins (1, 8, 9, 16) must be soldered to expanded copper lands on the PCB. Power dissipation depends strongly on slew settings - slower edges increase conduction losses - so thermal design must account for worst-case PD calculated from VIN, load current, DCMAX, and RVSL/RCSL values. The LT1534IS-1#PBF includes thermal shutdown at 125°C as a safety backup.

Can the LT1534IS-1#PBF be synchronized to an external clock, and why is this useful?

Yes, the LT1534IS-1#PBF can be synchronized to an external clock via the SYNC pin, which accepts a >1.4V square wave to trigger oscillator discharge. This capability allows precise placement of switching harmonics - for example, shifting them away from sensitive frequency bands used by ADC sampling clocks or RF receivers. In EMI-critical designs like medical imaging or spectrum analyzers, synchronizing the LT1534IS-1#PBF eliminates unpredictable beat frequencies and simplifies compliance testing. The LT1534IS-1#PBF supports sync frequencies up to 1.5× its free-run oscillator frequency.

What are the key differences between LT1534IS-1#PBF and the standard LT1534IS#PBF?

The LT1534IS-1#PBF differs from the LT1534IS#PBF in its oscillator frequency range: the "-1" suffix denotes a version with 20kHz–250kHz operation, whereas the base LT1534IS#PBF operates from 50kHz–500kHz. This lower-frequency range in the LT1534IS-1#PBF enables better EMI filtering (harmonics fall into more easily attenuated bands) and reduced switching losses in high-current boost applications. All other electrical characteristics, pinout, slew control, and dual-feedback functionality remain identical between the two variants - the LT1534IS-1#PBF is a frequency-binned variant optimized for noise-sensitive, low-frequency-switching use cases.