Analog Devices Inc. LTM4656EY-1#PBF

Overview

LTM4656EY-1#PBF from Analog Devices is a synchronous boost µModule regulator with integrated in-line input current protection, delivering up to 5A continuous output current across 6V–36V output range (set by single resistor) from 4.5V–28V input. It features programmable switching frequency (350kHz–780kHz), ±2% total output voltage regulation over load/line/temperature, and operates in a thermally enhanced 16mm × 16mm × 7.07mm BGA package. Used in telecom power supplies requiring high-density, short-circuit resilient 24V/4A conversion.

For engineers reviewing the LTM4656EY-1#PBF datasheet, LTM4656EY-1#PBF pinout, LTM4656EY-1#PBF application, or LTM4656EY-1#PBF equivalent, key selection criteria include input-output short protection behavior, adjustable compensation capability (LTM4656-1 variant), thermal derating at 125°C junction, 4mΩ internal sense resistor accuracy, and parallel current sharing support for higher-power systems.

Technical Context

The LTM4656EY-1#PBF integrates a fixed-frequency current-mode boost controller, power MOSFETs, inductor, and in-line protection circuitry in a single BGA module. Its dual-path architecture separates main power delivery (VIN→VOUT via boost stage) from front-end protection (VIN→BVIN via controlled MOSFET with 4mΩ sense resistor).

It implements a fault-timer-based protection scheme where TMR pin voltage ramps with VIN–SENSE1 differential, triggering FLT assertion at 1.275V and shutdown at 1.375V, followed by 33.6ms cooldown before auto-retry. Compensation is externally configurable via COMP pin-distinguishing it from the internally compensated LTM4656EY#PBF.

Key Specifications

Pinout & Package

The LTM4656EY-1#PBF uses a 144-ball BGA package (16mm × 16mm × 7.07mm) with exposed thermal pad on underside. Ball pitch is 0.8mm; MSL level 4. Package is RoHS-compliant with SAC305 finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTM4656EY#PBF, the LTM4656EY-1#PBF adds external compensation for precision transient response tuning, while LTM4655IY#PBF trades output current and thermal capacity for lower unit cost in less demanding applications.

Availability

LTM4656EY-1#PBF is available at Aetrix Electronics and suitable for telecom infrastructure, electronic test equipment, industrial motor interface, and medical imaging power systems requiring stable component supply, long-term lifecycle support, and guaranteed RoHS compliance.

Supply support for LTM4656EY-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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and industrial markets since 1965.

The LTM4656 product line delivers fully integrated, high-density power modules targeting applications needing robust, compact, and protected DC/DC conversion - especially where board space, reliability, and time-to-market outweigh discrete design flexibility.

FAQ

What is the key functional difference between LTM4656EY-1#PBF and LTM4656EY#PBF?

The LTM4656EY-1#PBF provides external access to the COMP pin for full loop compensation control, enabling customization of bandwidth and phase margin with diverse output capacitor types and values. In contrast, the LTM4656EY#PBF uses internal compensation and lacks COMP pin functionality - making it simpler for standard applications but inflexible for demanding transient response requirements. Both share identical pinout, protection features, and electrical specifications otherwise.

How does the in-line input protection in LTM4656EY-1#PBF respond during an output short-circuit?

During an output short, the LTM4656EY-1#PBF monitors input current via the 4mΩ internal sense resistor between VIN and SENSE1. When current exceeds the trip threshold (typically ~12.5A), the TMR pin begins charging linearly with VIN–SENSE1 voltage. At 1.275V, FLT asserts as warning; at 1.375V, the in-line MOSFET shuts off. After 33.6ms cooldown (TMR charges to 4.3V then discharges to 0.5V), LTM4656EY-1#PBF auto-retries - all without external components.

Can LTM4656EY-1#PBF be synchronized to an external clock, and how is this configured?

Yes, LTM4656EY-1#PBF supports external synchronization via the MODE_PLLIN pin. Applying a clean CMOS/TTL clock signal (350kHz–780kHz) to MODE_PLLIN forces the boost switching edge to align with the rising edge of that clock, eliminating beat frequencies and reducing EMI in sensitive systems. When unused, MODE_PLLIN defaults to Burst Mode® operation if left floating or pulled to GND, or pulse-skipping if biased between GND and INTVCC–1.3V.

What is the minimum output capacitance required for stable operation of LTM4656EY-1#PBF at 24V/4A?

LTM4656EY-1#PBF requires ≥150µF total output capacitance for stable 24V/4A operation, as validated in the typical application circuit (TA01a). This includes 100µF aluminum electrolytic plus two 10µF ceramic capacitors. Using only ceramic capacitors is supported but demands careful COMP network design - the LTM4656EY-1#PBF's external compensation capability enables this flexibility, unlike the non–-1 variant.

Does LTM4656EY-1#PBF support parallel operation, and what signals must be connected?

Yes, LTM4656EY-1#PBF supports parallel current sharing. To configure two or more units, connect all VFB pins together, tie all COMP pins together, synchronize FREQ pins (or use common MODE_PLLIN clock), and route shared SS and RUN signals. The modules automatically balance current within ±10% tolerance. Thermal derating must be applied per unit based on total power dissipation and PCB copper area - the 16mm × 16mm footprint allows tight placement without airflow interference.