Part Number: LTM4644IY#PBF

Manufacturer: Analog Devices Inc.

Description: DC DC CONVERTER 4X0.6-5.5V

Shipped from: Shenzhen/HK Warehouse

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Technical Specifications of LTM4644IY#PBF

Datasheet  LTM4644IY#PBF datasheet
Category Power Supplies – Board Mount
Family DC DC Converters
Manufacturer Linear Technology
Series μModule?
Packaging Tray
Part Status Active
Type Non-Isolated PoL Module
Number of Outputs 4
Voltage – Input (Min) 4V
Voltage – Input (Max) 14V
Voltage – Output 1 0.6 ~ 5.5 V
Voltage – Output 2 0.6 ~ 5.5 V
Voltage – Output 3 0.6 ~ 5.5 V
Current – Output (Max) 4A, 4A, 4A, 4A
Power (Watts) – Manufacture Series
Voltage – Isolation
Applications ITE (Commercial)
Features OCP, OTP, OVP
Mounting Type Surface Mount
Package / Case 77-BGA
Size / Dimension 0.59″ L x 0.35″ W x 0.19″ H (15.0mm x 9.0mm x 4.9mm)
Operating Temperature -40°C ~ 125°C
Power (Watts) – Max


The LTM4644IY#PBF is a versatile and highly efficient non-isolated switch-mode DC/DC power supply module with four outputs. In this detailed tutorial, we will look at the LTM4644IY#PBF’s essential features, specs, and applications to help you understand its capabilities and how to utilize it successfully in your projects.

What is the LTM4644IY#PBF?

The LTM4644IY#PBF is a non-isolated, quad-output DC/DC power supply module developed for a variety of power delivery applications. It has four independent regulator channels, each of which can deliver up to 4A of continuous output current. This module is well-known for its efficiency, adaptability, and small size, making it suitable for a wide range of electronic projects.


Certainly, the following are the major characteristics of the LTM4644IY#PBF:

  • Design with four outputs: The LTM4644IY#PBF has four separate regulator channels, allowing it to supply many loads at the same time with precise voltage control.
  • Wide Output Voltage Range: Each regulator channel may be precisely tuned to generate output voltages ranging from 0.6V to 5.5V, providing flexibility in fulfilling a wide range of voltage needs.
  • Input Voltage Flexibility: The module can operate over a wide input voltage range of 4V to 14V, and it can function from as low as 2.375V with the application of an external bias voltage.
  • Frequency Synchronization: The module offers external synchronization for applications sensitive to switching noise, allowing you to fine-tune the switching frequency between 700kHz and 1.3MHz.
  • Current Mode Control: The LTM4644IY#PBF maintains stability and outstanding transient performance with many types of output capacitors, including ceramic capacitors, by utilizing current mode control and internal feedback loop compensation.
  • With built-in clock interleaving and accurate current sharing, this module enables for customizable configurations such as 2+2, 3+1, or 4 channels parallel operation, making it perfect for multi-rail POL applications such as FPGA power distribution.
  • Internal comparators monitor output voltages, pulling the open-drain PGOOD (Power Good) output low if the feedback voltage exceeds a 10% window around the regulation point, boosting system safety.
  • Foldback Current Limiting: When the feedback voltage lowers during an overcurrent event, the module limits the inductor valley current to around 40% of its previous value, providing further protection.
  • Pulling the RUN pin below 1.1V causes the controller to enter shutdown mode, turning off both power MOSFETs and most internal control circuitry, allowing for efficient power management.
  • Tracking and Soft-Start: The TRACK/SS (Tracking/Soft-Start) pin is available for power supply tracking and soft-start programming, which aids in regulated power-up processes.

These fundamental characteristics make the LTM4644IY#PBF a versatile and dependable choice for powering a wide range of electronic devices and systems, particularly in applications requiring numerous regulated outputs, high efficiency, and precise voltage control.


● Output Channels

The LTM4644IY#PBF has four independent regulator channels, allowing you to power numerous loads either separately or in tandem.

● Output Voltage Range

Each regulator channel can be precisely programmed from 0.6V to 5.5V using a single external resistor (two resistors for LTM4644-1).

● Input Voltage Range

The module has an input voltage range of 4V to 14V and can function from as low as 2.375V with an external bias voltage.

● Synchronization Options

The module can be externally synced to a clock ranging from 700kHz to 1.3MHz for noise-sensitive applications.

● Control Modes

The LTM4644IY#PBF uses current mode control and internal feedback loop compensation to ensure stability and outstanding transient performance with a wide range of output capacitors, including ceramic capacitors.

● Current Monitoring and Protection

The module provides quick current monitoring on a cycle-by-cycle basis, foldback current limiting under overcurrent conditions, and overvoltage/undervoltage protection.


FPGA Power Solutions

The module provides quick current monitoring on a cycle-by-cycle basis, foldback current limiting under overcurrent conditions, and overvoltage/undervoltage protection.

Multi-Rail Point-of-Load (POL) Applications

This module’s four independent channels and parallel operating options simplify power distribution and assure dependable voltage regulation in multi-rail POL configurations.

Other Use Cases

In addition to FPGA and POL applications, the LTM4644IY#PBF can be used in a variety of projects that require high-efficiency power supplies, including as embedded systems, data acquisition, and communication equipment.

Operating Modes

● Continuous Conduction Mode (CCM)

CCM operation is the default mode and offers efficient power conversion for most load conditions.

● Discontinuous Conduction Mode (DCM)

DCM can be enabled at light load currents, optimizing efficiency compared to CCM mode.

Programming and Configuration

● Output Voltage Adjustment

The output voltage can be precisely adjusted using external resistors, allowing you to tailor the module to your specific voltage requirements.

● Synchronization and Phase Control

The LTM4644IY#PBF supports synchronization and phase control, allowing for precise timing and coordination in multi-module setups.

● Current Sharing and Parallel Operation

Parallel operation is made easy with built-in clock interleaving, enabling flexible configurations like 2+2 or 3+1 channels. Accurate current sharing ensures even distribution of load among regulators.

Protection and Reliability

● Overvoltage and Undervoltage Protection

The module’s internal comparator ensures that output voltages remain within a ±10% window around the regulation point, providing a reliable safety net.

● Foldback Current Limiting

In overcurrent conditions, the module reduces inductor valley current to approximately 40% of the original value when feedback voltage drops, enhancing system protection.

● Shutdown Control

The LTM4644IY#PBF can be shut down by pulling the RUN pin below 1.1V, turning off both power MOSFETs and most internal control circuitry.

Design Considerations

● Input and Output Capacitors

Selecting the appropriate input and output capacitors is critical for ensuring stable and efficient operation. The module is versatile enough to work with various capacitor types, including ceramic capacitors.

● Switching Frequency

The default switching frequency is 1MHz, but for noise-sensitive applications, you can synchronize it within the range of 700kHz to 1.3MHz.

● Thermal Management

Efficient heat dissipation is essential for maintaining reliable operation. Consider proper thermal design and heat sinking to prevent overheating.


We’ve covered the LTM4644IY#PBF, a versatile quad-output non-isolated DC/DC power supply module, in this guide. Its specifications, modes, and protective features make it an excellent choice for a wide range of applications, including FPGA power delivery and multi-rail POL configurations.

With the LTM4644IY#PBF, you can realize the full potential of your embedded system. For more information and purchases, visit ICRFQ, a reputable Chinese electronic component supplier, and embrace the future of flash memory technology.

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