How to address DC/DC noise, efficiency, and layout issues using integrated power modules
current is low and/or the input voltage is high. Looking at the LTM4626 and LTM4657 operating at the same switching frequency, and with the same 12-volt input and 5-volt output, the superior switching loss of the LTM4657 can be seen ( Figure 11 ). Additionally, its higher-value inductor reduces the output voltage ripple. However, the LTM4626 can supply more load current than the LTM4657. Users can assess the performance of the LTM4657 using the DC2989A demo board ( Figure 12 ), while for those who need to evaluate the LTM4626, the DC2665A-A board is available (Figure 13). The Silent Switcher µModules are not restricted to single- output modules. For example, the LTM4628 is a complete, dual 8 A
Figure 14: The LTM4628 can be configured as a dual-output, 8 A per channel switching DC/DC regulator, or in a single-output, 16 A output configuration. (Image source: Analog Devices)
output switching DC/DC regulator that can be easily configured to provide a single 2-phase 16 A output ( Figure 14 ). The module is offered in 15 mm × 15 mm × 4.32 mm LGA and 15 mm × 15 mm × 4.92 mm BGA packages. It includes the switching controller, power FETs, inductor, and all supporting components. The module operates over an input voltage range of 4.5 to 26.5 volts and supports an output voltage range of 0.6 to 5.5 volts, set by a single external resistor. Users can investigate its performance as a single or dual- output device using the DC1663A demo board ( Figure 15 ). Conclusion Designing a functioning DC/ DC regulator is fairly easy with available ICs. However, designing
a regulator that simultaneously excels in efficiency, is functionally complete, and meets the often various confusing and stringent regulator mandates is not. The Silent Switcher µModules from
Analog Devices simplify the design process. They eliminate risk by meeting the goals for cool and efficient operation, EMI emissions below allowed limits, and drop-in completeness.
Figure 11: The efficiency comparison of the LTM4626 and LTM4657 at 1.25 MHz with the same configuration on a DC2989A demonstration board shows modest but tangible differences. (Image source: Analog Devices)
Figure 15: Evaluation of the single/dual- output LTM4628 is accelerated with the use of its DC1663A demo board. (Image source: Analog Devices)
Figure 12: The DC2989A demo board is designed to speed the evaluation of the LTM4657 Silent Switcher. (Image source: Analog Devices)
Figure 13: For the LTM4626 Silent Switcher module, the DC2665A-A demo board is available to facilitate exercise and evaluation. (Image source: Analog Devices)
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