Analog Devices Inc. LT8570HMS8E-1#TRPBF

Overview

LT8570HMS8E-1#TRPBF from Analog Devices (formerly Linear Technology) is a 65V, 0.25A current-mode PWM DC/DC converter IC supporting boost, SEPIC, and inverting topologies. It features adjustable 200kHz–1.5MHz switching frequency, integrated soft-start, synchronization capability, and user-configurable undervoltage lockout. It delivers stable bias power for TFT-LCD and VFD displays in industrial temperature environments.

For engineers reviewing the LT8570HMS8E-1#TRPBF datasheet, LT8570HMS8E-1#TRPBF pinout, LT8570HMS8E-1#TRPBF application, or LT8570HMS8E-1#TRPBF equivalent, key selection criteria include its 0.25A switch current limit, –40°C to 150°C operating junction range, MSOP-8 package with exposed thermal pad, and dual feedback architecture enabling both positive and negative output configurations.

Technical Context

The LT8570HMS8E-1#TRPBF implements constant-frequency current-mode control with internal slope compensation, supporting duty cycles up to 85% at 200kHz and 75% at 1.5MHz. Its FBX pin accepts either 1.204V (noninverting) or 3mV (inverting) reference thresholds, enabling topology reconfiguration via external resistor routing without changing the IC.

It integrates frequency foldback during startup (reducing f_OSC to 1/6 nominal), a high-gain SHDN pin tolerant of slow-ramping input signals, and thermal shutdown activation at ~165°C with automatic soft-start restart upon cooldown. The VC pin provides direct access to the error amplifier output for custom loop compensation.

Key Specifications

Pinout & Package

LT8570HMS8E-1#TRPBF is housed in an 8-lead plastic MSOP package (MS8E) with exposed thermal pad (Pin 9 = GND), θ_JA = 35–40°C/W. The thermally enhanced layout supports continuous operation at full load in high-temperature environments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DC/DC converter applications.

Compared with LTC3589EUF#PBF and MAX17595ATP+T, the LT8570HMS8E-1#TRPBF uniquely combines integrated 65V/0.25A switching, inverting topology support, and –40°C to 150°C guaranteed operation in a single MSOP-8 package-making it optimal for space-constrained, high-reliability bias supplies where dual-polarity outputs or wide input ranges are critical.

Availability

LT8570HMS8E-1#TRPBF is available at Aetrix Electronics and suitable for TFT-LCD bias supplies, VFD display power, and GPS receiver local regulation requiring stable component supply across extended temperature and long production lifecycles.

Supply support for LT8570HMS8E-1#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 and maintains its precision analog and power management portfolio with rigorous qualification standards for industrial and automotive applications.

The LT8570 family was designed specifically for compact, high-voltage bias generation in display and communication infrastructure-emphasizing topology flexibility, thermal robustness, and seamless integration into space-limited PCB layouts.

FAQ

What is the maximum duty cycle supported by the LT8570HMS8E-1#TRPBF at 1.5MHz?

The LT8570HMS8E-1#TRPBF supports a maximum duty cycle of 75% at 1.5MHz, defined by its minimum off-time of 100ns. This limit ensures stable current-mode control and avoids subharmonic oscillation. At lower frequencies like 200kHz, the maximum duty cycle increases to 85%, enabling higher step-up ratios in boost and SEPIC configurations. Exceeding these values risks regulation loss and thermal stress on the internal switch.

Can the LT8570HMS8E-1#TRPBF generate negative output voltages?

Yes, the LT8570HMS8E-1#TRPBF can generate negative output voltages when configured in the dual-inductor inverting topology. Its FBX pin accepts a 3mV reference threshold for inverting operation, allowing output voltage setting via a single resistor from VOUT to FBX. The LT8570HMS8E-1#TRPBF maintains tight regulation and low ripple in this mode, making it suitable for VFD and op-amp bias applications requiring clean negative rails.

How does the SHDN pin enable programmable undervoltage lockout on the LT8570HMS8E-1#TRPBF?

The SHDN pin on the LT8570HMS8E-1#TRPBF features a high-gain comparator with 1.21V–1.40V activation window and 40mV hysteresis. By connecting a resistor divider from VIN to SHDN, designers set a precise turn-on threshold-for example, a 100kΩ/22kΩ divider enables startup at 5.5V. This eliminates external UVLO ICs and simplifies bias supply design. The LT8570HMS8E-1#TRPBF also restarts soft-start automatically upon SHDN reactivation.

What is the purpose of the frequency foldback feature in the LT8570HMS8E-1#TRPBF?

Frequency foldback in the LT8570HMS8E-1#TRPBF reduces switching frequency to 1/6 of nominal when the FBX pin voltage resides between 300mV and 920mV-typically during startup or overload. This lowers the minimum achievable duty cycle, preventing premature current-limit triggering and enabling smoother soft-start behavior. Once regulation is established and FBX exits that range, the LT8570HMS8E-1#TRPBF resumes full-frequency operation for optimal efficiency.

Which package variant does the LT8570HMS8E-1#TRPBF use, and why is thermal performance critical?

The LT8570HMS8E-1#TRPBF uses the 8-lead plastic MSOP (MS8E) package with an exposed GND pad soldered directly to the PCB thermal plane. Its θ_JA is rated 35–40°C/W, enabling reliable operation at full 0.25A switch current even at 150°C junction temperature. This thermal robustness is essential for bias supplies in sealed enclosures or high-ambient environments-ensuring the LT8570HMS8E-1#TRPBF meets lifetime reliability targets without derating.