Analog Devices Inc. LTC3616EUDD#PBF

Overview

LTC3616EUDD#PBF from Analog Devices (formerly Linear Technology) is a 6A, 4MHz monolithic synchronous step-down DC/DC converter with current-mode control, 2.25V–5.5V input range, ±1% output voltage accuracy, and 100% duty cycle low-dropout capability. It serves as a high-efficiency point-of-load regulator in battery-powered portable systems requiring stable 0.6V–VIN output with minimal quiescent current (75µA in Burst Mode).

For engineers reviewing the LTC3616EUDD#PBF datasheet, LTC3616EUDD#PBF pinout, LTC3616EUDD#PBF application, or LTC3616EUDD#PBF equivalent, key selection criteria include programmable switching frequency up to 4MHz, selectable operating modes (Burst/Pulse-Skipping/Forced Continuous), DDR memory termination support, active voltage positioning (AVP), and thermal performance in the 3mm × 5mm QFN package.

Technical Context

The LTC3616EUDD#PBF implements a constant-frequency, current-mode architecture with internal P-channel high-side and N-channel synchronous rectifier switches. Its peak-current sensing loop uses the ITH pin voltage to set per-cycle current limits, while the error amplifier compares VFB against a 0.6V reference to regulate output voltage across load and line variations.

Mode selection via the MODE pin directly configures control behavior: forced continuous mode enables bidirectional current flow for DDR termination (±3A), pulse-skipping reduces ripple at light loads, and Burst Mode minimizes IQ to 75µA by gating switching cycles. Frequency is set by RT/SYNC resistor, external clock (≤4MHz), or internal 2.25MHz oscillator.

Key Specifications

Pinout & Package

Package: 24-lead (3mm × 5mm) plastic QFN with exposed thermal pad (Pin 25 = PGND). Requires soldering of exposed pad to PCB ground plane for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS54620RGYT and MP2451DT-LF-Z, the LTC3616EUDD#PBF uniquely combines 6A output, 2.25V–5.5V input, DDR sinking, AVP, and 75µA Burst Mode IQ - making it optimal for space-constrained, battery-powered systems demanding both high efficiency and advanced regulation features.

Availability

LTC3616EUDD#PBF is available at Aetrix Electronics and suitable for point-of-load regulation, DDR memory termination, portable computer systems, and handheld devices requiring stable component supply with guaranteed long-term availability.

Supply support for LTC3616EUDD#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 precision analog and power management portfolio. Linear Technology was renowned for high-performance DC/DC converters, references, and amplifiers targeting demanding industrial and communications applications.

The LTC3616EUDD#PBF belongs to Linear's monolithic synchronous buck regulator family, designed specifically for high-current, low-voltage point-of-load applications in portable, computing, and memory subsystems where efficiency, small size, and advanced control features are critical.

FAQ

What is the maximum switching frequency supported by the LTC3616EUDD#PBF?

The LTC3616EUDD#PBF supports an externally programmable switching frequency up to 4MHz via the RT/SYNC pin. This can be set using a resistor to ground, an external clock signal, or by tying RT/SYNC to SVIN for the internal 2.25MHz oscillator. Operation at 4MHz enables use of very small inductors (e.g., 220nH) and compact ceramic capacitors, reducing solution footprint significantly.

Does the LTC3616EUDD#PBF support DDR memory termination with sinking current?

Yes, the LTC3616EUDD#PBF supports DDR memory termination with ±3A sinking current when the SRLIM/DDR pin is tied to SVIN. In this DDR mode, the device regulates VTT (termination voltage) and actively sinks current from the memory bus during read cycles, eliminating the need for external termination FETs and simplifying compliance with JEDEC DDR3/DDR4 specifications.

How does the Burst Mode operation of the LTC3616EUDD#PBF reduce quiescent current?

The LTC3616EUDD#PBF achieves 75µA quiescent current in Burst Mode by intermittently enabling and disabling the power switches based on load demand. When the average inductor current exceeds the load, the ITH voltage drops below an internal clamp, triggering sleep mode where internal circuits are powered down. The output capacitor sustains the load until VOUT droop re-enables regulation - minimizing switching losses at light loads.

What thermal considerations apply to the LTC3616EUDD#PBF in 6A operation?

The LTC3616EUDD#PBF uses a 24-pin 3mm × 5mm QFN with exposed PGND pad (θJA = 38°C/W). At 6A output, thermal design must ensure junction temperature stays ≤125°C (E-grade) under worst-case conditions. Adequate PCB copper (≥2 oz, thermal vias under exposed pad), proper PVIN/PGND layout, and airflow are essential - especially at high duty cycles or low input voltages where RDS(ON) increases.

Can the LTC3616EUDD#PBF be synchronized to an external clock, and what is the valid frequency range?

Yes, the LTC3616EUDD#PBF can be synchronized to an external clock applied to the RT/SYNC pin, with a valid synchronization frequency range of 0.3MHz to 4MHz. The internal slope compensation automatically adapts to the external clock frequency, ensuring stable current-mode operation. This feature prevents beat frequencies in multi-regulator systems and helps meet strict EMI requirements.