If DC/DC converters are required, the buy-or-build question is legendary. With the SQ24S family, Bel Power provides a compelling argument for Team Buy.

Based on the eighth-brick format but with a pinout compatible with the quarter-brick family, the family provides access to the legacy of well-known and well-liked physical form factors. In addition, the parts provide features such as galvanic insulation—a converter that can satisfy most demands in the power-supply space.

Trimming and Compensation for Accurate Voltage Regulation

Selecting the voltage to be output by an SQ24 is done by choosing the correct SKU. For example, SKU SQ24S15033-NS00G leads to a device with an operating voltage of 3.3V, while SKU SQ24S05080-PS00G yields eight volts. In practice, the application schematic presents itself as similar to the figure.

The regulator provides both current and sensing output pins. This permits the creation of a Kelvin connection (see https://www.youtube.com/watch?v=LAmc1_PtYAs for an explanation) and means that the regulator's control circuitry can eliminate ohmic losses on the way to the device.

Furthermore, the Rtrim resistor permits fine adjustments to the voltage. Usually, the adjustment range is +10%/-20%. For some parts, a range of +/- 10% is to be used instead.

Two Options Select the Correct Soft-start Mode

Feathering voltage regulators provide various benefits if a system spends time in standby mode. In the SQ24S family, Bel Power offers two modes: the NS00G version turns off when the enable pin is pulled high.

Using the on-off function is not mandatory; the control pin can also be hard-wired to the correct voltage to ensure that the regulator is always powered on. Furthermore, some variants provide pull-up or pull-down resistors on the board, thereby ensuring that the enable input is always in a defined state.

Circuit Design for Additional Stability

The SQ24S DC/DC converter family is designed as a one-stop shop for all power conversion applications. Theoretically, the design can be connected directly to the application using the terminals shown in the figure below.

The data sheet provides a variety of nomograms to permit the designer to assess the situation more accurately. Furthermore, the deployment of an input and an output capacitor is recommended to improve the regulator's stability.

Regulator stability is furthermore certified by compliance with a variety of safety standards: in particular, the data sheet claims the following:

x) High reliability: MTBF of 3.4 million hours, calculated per Telcordia TR- 332, Method I Case 1

x) All materials meet UL94, V-0 flammability rating

x) Approved to the latest edition and amendment of ITE Safety standards, UL/CSA 60950-1 and IEC60950-1

Finally, the SQ24S also eliminates the classic switching regulator behavior: all versions of the family operate stably without an external load.

Conclusion

If a high-performance and high-reliability DC/DC converter is needed, the SQ24S member family from Bel Power Solutions provides an attractive alternative to a home-built design.