UDM82821adj Magnetically Integrated DC-DC Buck Power Module ( 2.5V-5.5V Input, 0.8V~4.0V Output )

Features

Integrated power inductor on ferrite ceramic substrate, low EMI noise

Ultra-small footprint (2.5mm × 2.0mm, thickness 1.40mm or 1.10mm)

Integrated capacitors in a single-package plastic encapsulation, providing high reliability for surface mount applications

Synchronous rectification technology achieves high efficiency, up to 95%.

Automatic PFM/PWM Mode Switching Function

Achieves 2% voltage accuracy over the full load current range

Wide input voltage range:2.5V~5.5V

Maximum Load Current:

Vin =2.5V,   Iout ≤0.7A 

Vin=3.3V ， Iout ≤0.9A 

Vin=5.0V ，Iout ≤1A

Adjustable Output Voltage: 0.8V~4.0V

Internal soft start, short-circuit protection, over current Protection, and overtemperature protection

Applications

Digital Camera

Telecommunications and Network 

Applications, Optical Communications

Alternative to linear regulators (LDO)

Miniaturized applications

Description

The UDM82821adj is a low-power buck DC-DC converter module suitable for space-constrained and noise-sensitive applications. The module features an inductor-embedded ferrite substrate, which effectively reduces both radiated EMI noise and conducted noise. It uses a single-package plastic encapsulation to enhance mounting reliability.

By adding input/output capacitors, it can be used as an alternative to an LDO. Its low noise and ease of use ensure reliable power quality. The device smoothly switches between PFM and PWM modes based on the load current. Under light load conditions, it automatically switches to PFM mode to extend battery life. Under heavy load conditions, it automatically switches to PWM mode to ensure low ripple and high efficiency. The device maintains excellent output voltage accuracy even in PFM mode, keeping the output voltage accuracy within 2% over the entire load current range.

Typical Application Circuit

Note: Recommended Cin : 2.2uF/6.3V, Recommended Cout : 10uF/6.3V;Add more capacitance can decrease the ripple.

Pin Configuration

Top View

Electrical  Characteristics

Electrical Characteristics(continued)

Note: Stress above the values listed in the "Absolute Maximum Ratings" section may cause permanent damage to the device. Exposure to any absolute maximum rating condition for extended periods may affect the reliability and lifespan of the device.

Typical characteristics

Unless otherwise noted, test conditions are T_ambient = 25℃

Unless otherwise noted, test conditions are T_ambient = 25℃

Operation

Summary

The UDM82821adj is a DC-DC buck power module with synchronous rectification control, featuring an embedded inductor on a magnetic ceramic substrate. It integrates a control IC, power MOSFETs, and filtering capacitors. The module requires only input and output capacitors for operation. It has a small footprint and high power density, making it particularly suitable for applications with limited board space.

It uses a ceramic substrate with a shielded structure, providing excellent EMI resistance. It combines high reliability, good thermal conductivity, and low temperature rise.

The device smoothly switches between PFM and PWM modes based on the load current. Under light load conditions, it automatically switches to PFM mode to extend battery life. Under heavy load conditions, it automatically switches to PWM mode to ensure low ripple and high efficiency. The device maintains good output voltage accuracy even in PFM mode.

It maintains 2% output voltage accuracy over the entire load current range (0 to 600mA).

Internal Soft-Start (SS)

The soft start function is designed to prevent inrush current during module startup. The UDM82821adj has an integrated soft start feature: when the module is enabled, the typical soft start time is 200μs.

Active Output Capacitor Discharge

After EN is turned off, an internal resistive discharge path (230Ω) is provided between the output capacitor and ground.

Overcurrent Protection and Short Circuit (OCP)

The UDM82821adj features cycle-by-cycle current limit protection. When the inductor current peak exceeds the internal peak current limit threshold, the upper transistor is turned off and a counter begins. After about ten consecutive occurrences, the device will enter the EN off state. Approximately 1.3ms later, EN will turn on again, and the power module will perform a soft start.

Overtemperature Shutdown Protection (OTP)

To prevent damage from overheating, the UDM82821adj   stops switching when the internal chip temperature exceeds 160°C. Once the temperature falls below the threshold (typically 145°C), the module resumes operation.

Output Voltage Setting

The module internally integrates a pull-up resistor with a value of 120kΩ. The internal reference voltage is 0.8V. Customers can select the value of the pull-down resistor Rj based on their desired output voltage:

PACKAGE DESCRIPTION 

Soldering and Storage Precautions

Recommended Reflow Soldering Profile

Note:

1.Due to the larger size of the module, do not place the module on the bottom side of the board during reflow soldering to avoid module drop.

2. For bulk and unpackaged products, store them in a dry box (relative humidity should be kept below 10%). For products that are still in their original packaging, store them in a dry box whenever possible.

3.Before mounting, moisture-sensitive products must be baked according to strict baking conditions: bake for more than 48 hours at 125°C.