Power Electronics / Power Management


Infineon boosts power density with PowerStage 3x3 package

14 November 2012 Power Electronics / Power Management

Power Semiconductors are facing rising demands. Faster switching frequencies and higher operating temperatures provide a challenge for packaging and system concepts.

Notebooks of today and tomorrow require an increase of DC-DC voltage converters because of features such as HD DVD players, various network connections, and interfaces such as Bluetooth, wireless and USB. They have to be smaller, thinner and lighter.

Infineon’s answer to this trend is the introduction of products in the PowerStage 3x3 package.

PowerStage 3x3

The PowerStage 3x3 is a leadless SMD package which integrates the low-side and high-side MOSFET of a synchronous DC/DC converter into a 3,0 x 3,0 mm package outline with only 0,8 mm package height (Figure 1).

Figure 1. Layout of the PowerStage 3x3.
Figure 1. Layout of the PowerStage 3x3.

On the bottom of the package, two separate exposed pads are located which are optimised for the chip size of the low-side and the high-side MOSFET for advanced power dissipation.

Saving space dramatically

A simplified block diagram of a typical notebook-application is shown in Figure 2. Besides the power supply for the CPU, which requires high current and therefore high power dissipation capability, all other rails are in the range of 5 A to 10 A. That is where the PowerStage 3x3 fits ideally.

Figure 2. A simplified block diagram of a typical notebook application.
Figure 2. A simplified block diagram of a typical notebook application.

The typical topology for the power conversion in the above-mentioned applications is the buck converter. Today`s standard solution is realised in a 5 x 6 mm (SuperSO8) or 3 x 3 mm (S3O8) package. Figure 3 shows the comparison of the area consumption in a buck converter with one high-side and one low-side MOSFET.

Figure 3. Comparison of the area consumption in a buck converter.
Figure 3. Comparison of the area consumption in a buck converter.

With the PowerStage3x3, designers can dramatically save space compared to two single products.

Two different products

With the BSZ0907ND and BSZ0908ND, Infineon Technologies offers two different products in the PowerStage 3x3 package. Table 1 provides a summary of the most important parameters (typical values at 4,5 V driving voltage). Both products are realised in the OptiMOS 30 V voltage class which targets voltage regulation applications in the computing and telecom segment.

Table 1. BSZ0907ND und BSZ0908ND performance parameters.
Table 1. BSZ0907ND und BSZ0908ND performance parameters.

With its low Rds(on) values, the BSZ0907ND can handle 12,5 A (without airflow) and more, depending on the cooling conditions in the application. With higher Rds(on) values in the high-side and low-side MOSFET, the BSZ0908ND is designed to handle currents in the range of 5-10 A.

The Rds(on) ratio of both products is adjusted to fit a broad range of power conversions for different applications and especially for applications like mobile computing with a conversion from 21 V or 16 V down to 1,5 V.

Increasing efficiency

The QGD of the high-side MOSFET (in both products) is low in order to keep the switching losses balanced with the conduction losses and have very high peak efficiency; this is quite important especially in notebook applications where the system is working in low power range most of the time.

A low QG is realised in order to preserve high efficiency at very low load or when the system is in an idle state. This helps to maintain the battery charge for a longer time. The very low thermal resistance (55 K/W) allows the products to deliver up to 2,3 W of power; the interconnection of the chip and the pins are designed to handle 30 A, which can occur in the voltage regulation during load transients.

Top performances in the application

The PowerStage 3x3 not only offers a very compact solution for half-bridge MOSFETs itself, but also simplifies the layout of the overall buck converter. In Figure 4 an easy layout solution with the PowerStage 3x3 is shown. The area for the overall solution is 12 x 12 mm; this very dense layout is possible due to the optimised pinout of the package.

Figure 4. Simplified layout of the overall buck converter with PowerStage 3x3.
Figure 4. Simplified layout of the overall buck converter with PowerStage 3x3.

The input capacitance can be located easily between the drain of the high-side and the source of the low-side MOSFET. This minimises the parasitics of the connections. The two gates of the low-side and high-side MOSFETs can easily be connected to the driver on the bottom of the board through two small vias. The output filter can be accommodated on the right side of the package.

Efficiency measurements

With particular attention to the notebook market, some tests were performed in order to show the package’s capabilities as well as product performances. The tests are performed mainly under notebook conditions, but they can also be used as a reference for other applications.

Figure 5 shows the efficiency versus output current for two different input voltages: 12 V and 21 V. In the notebook application, 12 V corresponds to the operating conditions with a battery (3 cells Li-Ion) and 21 V is related to the adaptor output voltage. In both cases the efficiency is above 90% in the range of 20% to 80% of the output load. For low load condition (0,5 A) efficiency values above 80% can be achieved.

Figure 5. Measurement results for efficiency.
Figure 5. Measurement results for efficiency.

In Figure 6 the thermal capabilities of the package are shown; once a continuous current of 12,5 A is applied the top case temperature will not exceed 110°C.

Figure 6. Thermal capabilities.
Figure 6. Thermal capabilities.

In the waveforms in Figure 7, the VDS high-side MOSFET, low-side MOSFET and the input voltage are plotted. Conditions of the measurement are: VIN = 12 V, FSW = 500 kHz, VOUT = 1,5 V, L = 1,2 μH (Coilcraft SER1590, DCR = 0,8 mΩ); driver: PX3516.

The overshoot (the value of the maximum voltage during the oscillation across the device) on the low-side MOSFET is 23 V, which is below 80% of the VBDSS value specified in the datasheet. Also the damping factor of the ringing is high in order to have low noise irradiation and therefore low EMI influence. Especially for equipment with wave transmitters where many logic signals occur, this low noise irradiation provides a great benefit.

For more information contact Davis Moodley, Infineon, +27 (0)11 706 6099, www.infineon.com



Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Power efficiency and robustness in electronics design
Power Electronics / Power Management
Mouser Electronics recently announced a new eBook in collaboration with Analog Devices highlighting essential strategies for optimising power systems.

Read more...
USB Type-C-powered controllers
Future Electronics Power Electronics / Power Management
Diodes Incorporated has released two USB Type-C PD 3.1 extended power range sink controllers that can be embedded into battery-powered devices.

Read more...
Multicell battery monitoring
Altron Arrow Power Electronics / Power Management
The LTC6811 from Analog Devices is a multicell battery stack monitor that measures up to 12 series connected battery cells with a total measurement error of less than 1,2 mV.

Read more...
Full telemetry in tiny DC-DC converters
RS South Africa Power Electronics / Power Management
The FS160* series of µPOL DC-DC converters from TDK all offer full telemetry, provide increased performance, and are remarkable for extraordinary power density in the smallest sizes.

Read more...
Power IC supplies 1650 W
EBV Electrolink Power Electronics / Power Management
Power Integrations has announced a two-fold increase in power output from the HiperLCS-2 chipset with the new device now being able to deliver up to 1650 W of continuous output power.

Read more...
High-voltage step-down DC-DC converter
Altron Arrow Power Electronics / Power Management
The MAX17793 is a high-efficiency, high-voltage, synchronous step-down DC-DC converter with integrated MOSFETs operating over an input voltage range of 3 to 80 V.

Read more...
High-voltage contactors
RS South Africa Power Electronics / Power Management
TDK Corporation has announced two new additions to its high-voltage contactor portfolio for harsh environments: the HVC43MC with integrated mirror contact and the HVC45 with enhanced short-circuit current handling capability.

Read more...
Chokes rated at 36 A
RS South Africa Power Electronics / Power Management
TDK Corporation has launched the EPCOS SurfIND series, a new range of current-compensated ring core double chokes for high currents and surface mounting.

Read more...
RF arrestor provides robust protection
RFiber Solutions Power Electronics / Power Management
NexTek’s range of coaxial RF surge and lightning arrestors are designed and built to provide robust protection for any radio or coaxial RF transmission application.

Read more...
Wide-Bandgap Developer Forum 2025
Power Electronics / Power Management
To give designers the ultimate in design flexibility, the entire range of WBG power semiconductors will be provided including discretes, modules, and highly integrated solutions ranging from 40 V to 700 V for GaN and 400 V to 3,3 kV for SiC.

Read more...