MICRO DC/DC

Introduction

Semiconductors and electronic components in applications ranging from industrial to wearables, such as I/O Terminals, Industrial Sensors to smartwatches and IoT, must be compact and low-profile. 

Lowering the voltage and increasing the current of these semiconductor components has led to a growing reliance on DC/DC converters, which offer greater efficiency and thermal performance compared to typical voltage regulators.

Typically, DC/DC converters consist of a control IC, coil, capacitors, and resistors. While they provide efficiency benefits, they require a larger mounting area than series regulators, increasing circuit board costs. Additionally, poor component selection and suboptimal circuit board layout can cause malfunctions and noise issues.

Micro DC/DC converters are gaining attention as a solution to these challenges. With fewer components, they simplify circuit board layout, reduce noise, and shorten development time.

The below page provides an overview of “Micro DC/DC” converters and key considerations for their use

One Concept - Four Solutions

TOREX’s "Micro DC/DC" converter XCL Series products focus on single output switching regulators with an integrated control IC and coil.

The package construction is determined taking into consideration the product specifications, IC, coil, and heat generation (dissipation) among other factors.

Each package construction has its own advantages so you can choose the one that best fits your application.

 

Table 1: Structure and Features of Micro DC/DC Converters

Structure Name	Pocket Type	Stack Type	Multiple Type	Cool Post Type
Drawing
Description	The IC is covered by the coil.	The IC is covered by the coil.	The IC and coil are placed side-by-side.	The molded IC is stacked under the coil.
Features	⦾ Radiated noise  ⦾ Near magnetics field △ Cost  ⦾ Mounting area  ○ Large current  ○ Heat dissipation	○ Radiated noise △ Near magnetics field  ⦾ Cost  ○ Mounting area △ Large current △ Heat dissipation	○ Radiated noise  ○ Near magnetics field  ○ Cost △ Mounting area  ⦾ Large current  ⦾ Heat dissipation	○ Radiated noise  ○ Near magnetics field  ○ Cost  ○ Mounting area  ○ Large current  ⦾ Heat dissipation

• Pocket Type

IC package and coil are adhered together.

This shortens the switching current path and produces very little noise.

• Stack Type

This is a plastic mold that mounts the IC chip on the coil.

General-purpose coils are used making this type relatively inexpensive.

• Multiple Type

This is a plastic mold that places the coil and IC chip next to each other.

This provides good heat dissipation from the IC and coil, so this package is optimum for high currents.

• Cool Post Type

A copper post passes through the plastic mold to connect the coil on top to the circuit board with low resistance and low thermal resistance.

This achieves high efficiency and high heat dissipation regardless of the stack configuration.

 

Package construction optimal for low EMI

To obtain sufficient performance from the electrical devices, it is important to take into consideration noise from the circuit design stage to suppress the generation of noise. 

Component selection is done last, however, regardless of the knowledge the power supply circuit is a source of noise generation.  If the design of the power supply circuit is poor, the expected performance cannot be obtained no matter how high the performance of the IC or LSI used.

TOREX’s "Micro DC/DC" converters have various measures to achieve low EMI, which are listed below: -

• Uses coils with low magnetic flux leakage
• Optimised coil characteristics for use with "Micro DC/DC" converters
• Optimised DC/DC converter operation
• Pin position and construction take current path into consideration

 

 

With the above graphics, the XC9288 (bottom left waveform) generates noise in the wide range of 30MHz-1GHz. We can see that XCL240 bottom middle waveform), on the other hand, has a very low noise level.

This shows there is a clear difference between the two despite them having the same operating frequency.  For this reason, the XCL240 Micro DC/DC converter is easy to use as a countermeasure for noise that has been left unresolved until late in the design process.

In addition, XCL242 (Fosc=1.2MHz), which has the same construction and pin layout as XCL240, has a lower operating frequency, and thus even lower noise (bottom right waveform).

With Near Magnetic Field Strength of the three products XC9288, XCL240 and XCL242 the XC9288 has a frequency range of 30MHz-1GHz, which is shown by the orange and red rings around the IC. We can see that the strongest noise is in the vicinity of the GND terminal. Yellow ring-shaped noise can also be seen at the coil. The coil is a simple shielded type (plastic mixed with ferrite powder) and the magnetic flux leakage is showing up as noise. On the other hand, there is no orange or red colour for XCL242 showing that it generates little noise.
 

Regulator Circuit DC/DC Performance

The "Micro DC/DC" converter can be used for switching even without a deep knowledge of power supplies, so the DC/DC converter can be used as if it were an LDO.

The efficiency and heat generation can be greatly reduced compared to using an LDO. Further, the main peripheral components are just an input capacity and an output capacity, so the DC/DC converter can be configured in a small size the same as for an LDO.
 

Significant miniaturisation of power supply circuit

The "Micro DC/DC" converter requires half the mounted space of a conventional DC/DC converter, which is configured as a discrete component, which lowers circuit board cost. 

In summary: -

• Achieves a significant reduction in mounting area and providing smallest class of power supply solution.
• Unique package structure / Optimum inductor for the internal IC.
• Efficient heat dissipation performance with structures that connect IC/coil and substrate with low thermal resistance

 

 

Want to see them in action? Watch the below video now and get in touch with us directly or your nearest Torex distributor for more details!

 

MICRO DC/DC SOLUTIONS

Synchronous DC/DC Converters with Integrated Coil

 

Low Voltage Buck Micro DC/DC for Output Currents up to 500mA

Specification Series		XCL210	XCL232	XCL233	XCL201/02	XCL208/09	XCL241/42
Configuration		BUCK
Output Current		50mA / 200mA	150mA	150mA	400mA	400mA	500mA
ON Resistance (Typ.)	N-Ch	0.40Ω	0.40Ω	0.40Ω	0.52Ω	0.52Ω	0.24Ω
	P-Ch	0.40Ω	0.35Ω	0.35Ω	0.42Ω	0.42Ω	0.16Ω
Input Voltage Range		2.0V ~ 6.0V	1.8V ~ 6.0V	1.8V ~ 6.0V	2.0V ~ 6.0V	1.8V ~ 6.0V	2.5V ~ 5.5V
Output Voltage	Fixed	1.0V ~ 4.0V	0.5V ~ 3.6V	0.5V ~ 3.6V	0.8V ~ 4.0V	0.8V ~ 4.0V	0.8V ~ 3.6V
	Adjustable	-	-	-	-	0.8V ~ VIN	-
Switching Frequency		PFM	PFM	PFM	1.2MHz	3.0MHz	1.2MHz
Quiescent Current		0.5μA	0.2μA	0.2μA	15μA	21μA	15μA
Protection Circuits	Current Limit	YES	YES	YES	YES	YES	YES
	Short Circuit	YES	-	YES	-	-	YES
	Inrush Current	-	-	-	-	-
Product Select	Fixed PWM	-	-	-	XCL201	XCL208	XCL241
	PWM/PFM Auto	-	-	-	XCL202	XCL209	XCL242
	PWM/PFM + Mode	-	-	-	-	-	-
	Fixed PFM	XCL210	XCL232	XCL233	-	-	-
Additional Features	Soft-start	-	YES	YES	YES	YES	YES
	UVLO	YES	YES	YES	YES	YES	YES
	CL Auto Discharge	YES	YES	YES	YES	YES	YES
	Others	-	-	VSET	-	-	-
Internal Inductor Value		8.0μH	2.2μH	2.2μH	4.7μH	1.5μH	2.2μH
Inductor Options		Multilayer	Multilayer	Multilayer	Multilayer	Multilayer	Multilayer
Package		CL-2025-02	CL-2025-03	CL-2025-03	CL-2025-02	USP-10B03	CL-2025-02
Dimensions (mm)		2.0 x 2.5 x 1.0	2.5 x 2.0 x 1.04	2.5 x 2.0 x 1.04	2.0 x 2.5 x 1.0	2.15 x 2.5 x 1.05	2.5 x 2.0 x 1.04
Operating Temperature Range		-40 °C ~ +85 °C	-40 °C ~ +85 °C	-40 °C ~ +85 °C	-40 °C ~ +85 °C	-40 °C ~ +85 °C	-40 °C ~ +105 °C
Product Page		XCL210	XCL232	XCL233	XCL201/02	XCL208/09	XCL241/42

 

Low Voltage Buck Micro DC/DC for Output Currents from 600mA

 

Boost Micro DC/DC

Specification Series		XCL100/01	XCL102/03	XCL104/05	XCL109/10	XCL108
Configuration		BOOST
Output Current		More than 100mA	Up to 500mA	Up to 710mA	Up to 610mA	Up to 400mA
ON Resistance (Typ.)	N-Ch	0.6Ω	0.3Ω	0.17Ω	0.17Ω	0.27Ω
	P-Ch	0.65Ω	0.3Ω	0.23Ω	0.20Ω	0.20Ω
Input Voltage Range		0.7V ~ 5.5V	0.65V ~ 6.0V	0.65V ~ 6.0V	0.65V ~ 6.0V	0.65V ~ 5.5V
Output Voltage	Fixed	1.8V ~5.0V	2.2V ~ 5.5V	1.8V ~ 5.5V	2.2V ~ 5.5V	3.0V ~ 5.5V
	Adjustable	-	-	-	-	-
Switching Frequency		1.2MHz	3.0MHz	1.2MHz	3.0MHz	1.2MHz
Quiescent Current		6.3μA	26μA	19μA	30μA	400nA
Product Circuits	Current Limit	-	YES	YES	YES	YES
	Short Circuit	-	YES	YES	YES	-
	Thermal Shutdown	-	-	YES	YES	-
Control Method	Fixed PWM	-	XCL102	XCL104	XCL109	-
	PWM/PFM Auto	-	XCL103	XCL105	XCL110	-
	Fixed PFM	XCL100/01	-	-	-	XCL108
Additional Features	Soft-start	YES	YES	YES	YES	YES
	UVLO	XCL100	-	YES	YES	-
	CL Auto Discharge	-	YES	YES	YES	-
	Others	Load Disconnect	Load Disconnect	Load Disconnect	Load Disconnect	Load Disconnect
		Input Bypass Mode	Input Bypass Mode	Input Bypass Mode	Input Bypass Mode	-
		-	-	VOUT "OR"	-	-
Internal Inductor Value		4.7μH	1.5μH	4.7μH	2.2μH	4.7μH
Inductor Options		Multilayer	Multilayer	Multilayer	Multilayer	Multilayer
Package		CL-2025-02	CL-2025-02	DFN3030-10B	CL-2025-02	CL-2025-02
Dimensions (mm)		2.0 x 2.5 x 1.0	2.0 x 2.5 x 1.0	3.0 x 3.0 x 1.7	2.0 x 2.5 x 1.0	2.0 x 2.5 x 1.0
Operating Temperature Range		-40 °C ~ +85 °C	-40 °C ~ +85 °C	-40 °C ~ +105 °C	-40 °C ~ +105 °C	-40 °C ~ +105 °C
Product Page		XCL100/01	XCL102/03	XCL104/05	XCL109/10	XCL108