FHT4644C/D 4-Channel DC/DC Buck Power Module with Adjustable Outputs ( 4.5V-14V Input, 0.6V-5.5V Output )

Features

4A full load output current per circuit

Input voltage range: 4.5V-14V

Output voltage: 0.6V-5.5V

Switching frequency: 600KHz, 1.1MHz selectable

Up to 92% efficiency

Internal 1mS soft start (additional external 1mS

optional)

±2% total output voltage regulation

Over-current protection, over-temperature

protection, over-voltage protection, UVLO

Flat and small size:

LGA package (9mm*15mm*4.32mm)

BGA package (9mm*15mm*5.01mm).

Applications

Multi-rail load point regulation

DSP, FPGA, ASIC applications

Description

The FHT4644C/D is a non-isolated, step-down, one-piece, molded-point power supply for

embedded, high-current negative with a size of only 9×15×4.32mm, it can be placed directly

next to the FPGA/CPU, which is ideal for low output voltage and multiplexed applications. The small-sized LGA (Land Grid Array) and BGA (Ball Grid Array) packages integrate ICs, inductors, and

corresponding components, requiring only a voltage-adjusting resistor and a few input and output ceramic

capacitors on the periphery to rapidly complete the design of a multi-channel power supply system. This simplifies the system design and maximizes PCB space savings. Designed based on synchronous rectification Buck topology, it supports a maximum current of 4A per channel

and offers high power conversion efficiency. It can convert voltages from 4.5V to 14V to 0.6V to 5.5V, providing

four-channel ON/OFF control and four-channel Power Good signals. Additionally, it features OCP (Over Current Protection), OVP (Over Voltage Protection), UVP (Under Voltage Protection), and OTP (Over Temperature Protection) functions.

Typical Applications

Quad Output Application Circuit

High voltage (input voltage) enable                         Low voltage enable

Pin Configuration

TOP VIEW

Electrical Characteristics

NOTE : Stresses above the values listed in the "Limit Values" section may cause permanent damage to the device. Prolonged exposure to any of the absolute maximum

ratings may affect the reliability and life of the device.

Operation

The FHT4644 is a four-channel independently outputting, non-isolated DC/DC switching regulator. It features four independent regulator channels, each capable of delivering up to 4A of continuous output current, requiring only a small amount of external input and output capacitors. Within an input voltage range of 4.5V to 14V, each regulation channel can provide a precisely adjustable output voltage ranging from 0.6V to 5.5V through an external resistor.

Input Voltage Setting

The FHT4644 is a step-down module where the output voltage is set to be less than the input voltage. Table 1 Input and output voltage relationship table (in nominal voltage)

Output Voltage Setting

Within the FHT4644, this pin is connected to theVOUT terminal of each channel through a 60.4kΩ precision resistor. The output voltage of the module can be controlled by programming the resistance between the FB and GND pins. The calculations are shown below: refer to the formula below:

Note: It is recommended to reserve two resistor positions for fine-tuning the output voltage.

Table 1 RFB resistor vs. each output voltage

Operating mode and switchingfrequency selection 

Two modes, Forced CCM and Pulse skip, are available under light load conditions. Two different switching frequencies and two light load modes can be realized by switching the resistor RM between the mode and GND or VCC. The recommended switching frequency is 600KHZ, Forced CCM, and higher switching frequencies will increase the switching losses of the power supply module. 

Table 2 Rm resistance versus mode and frequency

Soft Start

The module has a built-in soft-start, and an external soft-start pin is available, which can be connected to a ceramic capacitor of about 0.1uF to increase the delay time.

Input under-voltage protection

A resistor divider is connected between VIN and ground, with the center tap to the EN pin. When VIN drops to a specific value, EN drops below 1.15V and under-voltage lockout occurs. 

Output over-current protection

When the output current exceeds the current limit value, the FHT4644 enters the protection state. When the output current returns to the normal range, the converter enters normal operation. 

Over-temperature protection

When the case temperature of the FHT4644 rises above 140 °C, it enters an over-temperature protection state

Package Description

Soldering and Storage Precautions

For lead-free BGA solder ball products, the peak temperature should not exceed 245℃; For leaded BGA

solder ball products, the peak temperature should not exceed 225℃. Recommended reflow soldering profile for reference recommended curves for reference:

Lead Free Processes                                               Leaded Processes

Caution:

   1. Due to the large size of the module, please do not place the module under the board for reflow soldering to avoid falling off. 2.For bulk products and those that have been taken out of their original packaging, they should be

   2. stored in a desiccator (with a relative humidity of less than 10% inside). For products still in their original packaging, they should also be stored in a desiccator whenever possible. 

   3. Before mounting on the board, it is necessary to strictly follow the baking conditions to dry the samples: bake at 125°C for more than 48 hours, and control the reflow soldering temperature within 245°C.