Analog Devices Inc. LTC3615HFE-1#PBF

Overview

LTC3615HFE-1#PBF from Analog Devices (formerly Linear Technology) is a dual-channel, 3A synchronous step-down DC/DC converter in thermally enhanced 24-pin TSSOP package, operating from 2.25V to 5.5V input and delivering two independent 0.6V–5.5V outputs with ±1% feedback accuracy and 100% duty cycle low-dropout capability. It supports 140°/180° inter-channel phase shift for ripple reduction in portable computing and DDR memory termination applications.

For engineers reviewing the LTC3615HFE-1#PBF datasheet, LTC3615HFE-1#PBF pinout, LTC3615HFE-1#PBF application, or LTC3615HFE-1#PBF equivalent, key selection considerations include its high-temperature rated –40°C to 150°C junction range, programmable slew rate limiting via SRLIM pin, external synchronization up to 4MHz, selectable Burst/Pulse-Skipping/Forced Continuous modes, and internal AVP support for DDR I/O supply tracking.

Technical Context

The LTC3615HFE-1#PBF implements current-mode, constant-frequency control with dual independent channels sharing a common oscillator and reference. Its PHASE pin selects fixed 140° or 180° inter-channel offset-distinct from the 0°/90°/180° options of the non–"-1" variant-enabling optimized input current ripple cancellation in dual 3A or single 6A configurations.

Each channel features programmable soft-start via TRACK/SS pins, internal or external compensation at ITH pins, and MODE pin–controlled operation across Burst Mode (130µA IQ), Pulse-Skipping, or Forced Continuous modes. The device integrates P-channel high-side and N-channel synchronous rectifier switches with 75mΩ/55mΩ typical R_DS(ON), eliminating external diodes and supporting bidirectional current flow in sinking mode.

Key Specifications

Pinout & Package

Package: 24-lead plastic eTSSOP (FE package), 4.4mm × 7.8mm body, exposed PGND pad (Pin 25) requiring PCB soldering for thermal and electrical performance (θ_JA = 33°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS543B20RJER and LTC3633AIFE#PBF, the LTC3615HFE-1#PBF uniquely delivers true dual-channel operation with factory-configured 140°/180° phase shift, integrated DDR sinking, and guaranteed 150°C junction operation - making it optimal for compact, high-reliability dual-rail systems where analog control and thermal robustness are prioritized over digital configurability.

Availability

LTC3615HFE-1#PBF is available at Aetrix Electronics and suitable for portable computer systems, DDR memory termination, and distributed power supplies requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC3615HFE-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 its legacy of high-performance analog and power management ICs with rigorous automotive and industrial qualification standards.

The LTC3615HFE-1#PBF belongs to Linear's high-efficiency synchronous buck regulator product line, designed specifically for space-constrained, thermally demanding applications such as portable computing, DDR memory interfaces, and industrial point-of-load systems.

FAQ

What is the maximum operating junction temperature for the LTC3615HFE-1#PBF?

The LTC3615HFE-1#PBF is fully specified and guaranteed over a junction temperature range of –40°C to 150°C. This high-temperature rating is validated per Linear Technology's H-grade qualification standard and enables deployment in under-hood automotive modules, industrial motor drives, and sealed embedded systems where ambient temperatures exceed 105°C. Thermal derating above 125°C is recommended to ensure long-term reliability.

How does the PHASE pin configure inter-channel timing in the LTC3615HFE-1#PBF?

In the LTC3615HFE-1#PBF, the PHASE pin selects between two fixed phase offsets: tying PHASE to SGND configures 140° shift, while connecting it to SVIN selects 180°. Unlike the base LTC3615, the "-1" variant does not support 0° or 90° options. This 140°/180° selection minimizes input current ripple in dual 3A configurations and is implemented via internal PLL-based phase alignment - no external timing components required.

Can the LTC3615HFE-1#PBF support DDR memory termination with sinking current?

Yes - the LTC3615HFE-1#PBF supports DDR termination when the SRLIM pin is tied to SVIN, enabling DDR mode with ±1.5A per channel sinking capability. In this mode, the bottom N-channel MOSFET actively sinks current during data bus transitions, meeting JEDEC SSTL-18 and HSTL Class I requirements. The device maintains ±1% output accuracy and fast transient response without requiring external current-sink FETs.

What are the key differences between LTC3615HFE-1#PBF and LTC3615HFE#PBF?

The LTC3615HFE-1#PBF implements a fixed 140°/180° phase shift configuration, whereas the LTC3615HFE#PBF supports 0°/90°/180°. This makes the "-1" variant optimized for applications requiring asymmetric phase alignment to minimize input ripple in specific dual-output topologies. Both share identical thermal rating (–40°C to 150°C), pinout, and feature set - only the PHASE logic and associated internal routing differ.

Does the LTC3615HFE-1#PBF require external compensation components?

No - the LTC3615HFE-1#PBF supports both internal and external compensation. Tying the ITH1/ITH2 pins to SVIN enables internal compensation and Active Voltage Positioning (AVP) for DDR applications. For custom loop response tuning, external RC networks can be connected from ITHx to SGND. Internal compensation simplifies design and reduces BOM count, while external compensation provides flexibility for challenging transient or stability requirements.