Optimizing the performance of low load current designs, this "little guy" can provide a higher efficiency solution

The LTM4657 combines the high efficiency of the LTM4638 and the compact size of the LTM4626, and is an intermediate product between the LTM4626 and LTM4638.

The LTM4657 provides up to 8 A of continuous output current over an input voltage range of 3.1 V to 20 V. The LTM4657 uses the same component package (CoP) design as the LTM4626 and LTM4638, which helps the device dissipate heat quickly while maintaining a tiny 6.25 mm × 6.25 mm package size. The LTM4626, LTM4638 and LTM4657 are pin-compatible and have exactly the same size, allowing customers to leverage previous layout designs and easily select the µModule device that meets their needs.

The LTM4626, LTM4638 and LTM4657 are market leading step-down solution power density products. Small size, high efficiency µModule devices can be used to build flexible complete solutions for various applications. The internal integrated inductor, FET, upper feedback resistor, frequency resistor and optional internal compensation enable the step-down solution to use very few external components. While supporting a very simple design, the µModule technology uses a 49-pin BGA package to provide a large number of optional features to maximize the number of pins.

In addition to the common functions provided by the PGOOD, RUN and TRACK/SS pins, the LTM4657 also provides CLK _IN , CLK _OUT and PHMODE pins to improve parallel and EMI operation performance. In addition, a remote differential amplifier is used to improve output voltage accuracy. In addition, the internal thermal protection is improved through the temperature sensing pin.

The LTM4657 uses a larger inductor than the LTM4626 and LTM4638, which allows the device to run at a lower frequency, reducing switching losses. The LTM4657 is a preferred solution for solving the challenges of high switching losses and low conduction losses, such as in applications with low load current and/or high output voltage.

Figure 4 shows the comparison of the LTM4626 and LTM4657 using the same switching frequency and the same configuration on the DC2989A demo board. The 12 VIN, 5 V _OUT configuration fully demonstrates the excellent switching loss performance of the LTM4657. The LTM4657 uses a larger value inductor, which can also reduce the output voltage ripple. However, the LTM4626 can provide higher load current than the LTM4657.

The LTM4657 provides a satisfactory high efficiency solution for customers who need low switching losses and high efficiency in low to medium load applications (up to 8 A). The LTM4657 uses a tiny package and provides multiple features to provide high efficiency in space-constrained designs without compromising performance.