Analog Devices Inc. LT8570HDD-1#TRPBF

Overview

LT8570HDD-1#TRPBF from Analog Devices (formerly Linear Technology) is a 65V, 0.25A monolithic PWM DC/DC converter IC optimized for boost, SEPIC, and inverting topologies in high-reliability industrial power supplies. It features adjustable 200kHz–1.5MHz switching frequency, integrated soft-start, synchronization capability, and user-configurable undervoltage lockout. Designed for TFT-LCD bias supplies and GPS receivers requiring stable negative or positive regulated outputs up to ±12V.

For engineers reviewing the LT8570HDD-1#TRPBF datasheet, LT8570HDD-1#TRPBF pinout, LT8570HDD-1#TRPBF application, or LT8570HDD-1#TRPBF equivalent, key selection criteria include its 0.25A current limit, –40°C to 150°C junction temperature rating, 65V switch voltage tolerance, and compatibility with thermally enhanced 3mm × 3mm DFN packaging for compact, high-temperature PCB layouts.

Technical Context

The LT8570HDD-1#TRPBF employs constant-frequency current-mode control with internal slope compensation to ensure stability across duty cycles up to 85% at 200kHz. Its dual-feedback architecture supports both noninverting (1.204V reference) and inverting (3mV reference) configurations via a single FBX pin, enabling seamless topology reconfiguration without component changes.

It integrates a high-gain SHDN pin accepting slowly ramping enable signals, frequency foldback during soft-start (reducing minimum duty cycle to 1/6 nominal), and thermal shutdown at ~165°C with automatic restart at ~160°C. The VC pin provides direct access to the error amplifier output for external loop compensation using RC networks.

Key Specifications

Pinout & Package

LT8570HDD-1#TRPBF is housed in an 8-lead, 3mm × 3mm plastic DFN package with exposed thermal pad (Pin 9 = GND). The package delivers θ_JA = 43°C/W and requires soldering of the exposed pad to the PCB ground plane for thermal and electrical integrity.

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 LT8570HDD-1#TRPBF uniquely combines 65V integration, 0.25A capability, topology flexibility, and H-grade temperature range in a single 3mm × 3mm DFN-enabling compact, robust bipolar power solutions where programmability or ultra-high current are secondary to reliability and board space.

Availability

LT8570HDD-1#TRPBF is available at Aetrix Electronics and suitable for TFT-LCD bias supplies, GPS receiver power systems, and VFD display drivers requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for LT8570HDD-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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors for precision, industrial, and automotive applications.

The LT8570 family was designed specifically for compact, high-voltage DC/DC conversion in space-constrained industrial and communications equipment where topology flexibility and thermal resilience are critical.

FAQ

What is the maximum duty cycle supported by the LT8570HDD-1#TRPBF at 1.5MHz switching frequency?

The LT8570HDD-1#TRPBF supports a maximum duty cycle of 40% at 1.5MHz, derived from its 100ns minimum off-time specification. This limitation ensures stable current-mode control and prevents subharmonic oscillation; for higher duty-cycle requirements, operation at lower frequencies (e.g., 200kHz, where max duty cycle reaches 85%) is recommended. Always verify loop stability using the manufacturer's compensation guidelines when operating near DCMAX.

Can the LT8570HDD-1#TRPBF be used to generate a negative output voltage without external op-amps?

Yes, the LT8570HDD-1#TRPBF can generate negative output voltages directly using its inverting topology configuration. By connecting the FBX pin to the negative output through a single resistor, the internal 3mV reference enables regulation without external amplifiers or level shifters. The datasheet-provided equation R_FBX = (|V_OUT| + 3mV)/83.3µA ensures accurate setting of –5V, –12V, or other negative rails with standard resistor values.

How does the SHDN pin of the LT8570HDD-1#TRPBF differ from standard enable inputs?

The SHDN pin of the LT8570HDD-1#TRPBF features high-gain input circuitry with 40mV hysteresis and thresholds of 1.21V (falling) and 1.40V (rising), allowing it to accept slowly varying signals such as thermistor-based thermal enable or RC-filtered microcontroller GPIOs. Unlike conventional enable pins, it also integrates undervoltage lockout functionality-when combined with a resistor divider from VIN, it provides programmable input UVLO without external comparators.

What is the purpose of the frequency foldback feature in the LT8570HDD-1#TRPBF?

Frequency foldback in the LT8570HDD-1#TRPBF reduces the switching frequency to 1/6 of its nominal value when the FBX pin voltage falls within 300mV–920mV-typically during startup or overload conditions. This extends the minimum achievable duty cycle, improving control of peak switch current and preventing premature current-limit triggering. It enhances reliability in high-capacitance or short-circuit scenarios without requiring external soft-start circuitry.

Is the LT8570HDD-1#TRPBF pin-compatible with other members of the LT8570 family?

Yes, the LT8570HDD-1#TRPBF shares identical pinout and footprint with all LT8570 and LT8570-1 variants in the 8-lead DFN (DD) package, including LT8570HDD#TRPBF and LT8570IDD-1#TRPBF. This allows direct substitution between current-rated (0.25A vs. 0.5A) and temperature-grade (H vs. I) versions without PCB redesign-though designers must verify that the 0.25A limit and thermal performance meet application requirements.