Efficient monolithic buck converter reduces switching jitter

The LCT7130 constant frequency peak current mode synchronous step-down DC/DC converter from Linear Technology Corp. has a temperature-compensated ultralow DCR current sensing that enables maximum efficiency in high-current applications and also reduces switching jitter in low DCR applications.

The device has clock synchronisation functions, and a unique architecture that eases compensation and offers the ability to directly parallel multiple ICs for higher current capability. It also enhances the signal-to-noise ratio of the current sense signal, enabling the use of a very low DC resistance power inductor to maximise efficiency in high current applications. This feature also reduces the switching jitter commonly found in low DCR applications and improves current limit accuracy.

Figure 1: 20VIN, 20A Monolithic Synchronous Buck Converter

with Differential Output Sensing

Enabling a wide variety of applications

The LTC7130's 4.5V to 20V input range supports a wide variety of applications, including most intermediate bus voltages, and is compatible with many battery types. Integrated N-channel MOSFETs can deliver continuous load currents as high as 20A at output voltages ranging from 0.6V to 5.5V, making it ideal for point-of-load applications such as high current / low voltage DSP / FPGA / ASIC reference designs. Other applications include telecom/datacom systems, distributed power architectures and general high power density systems.

Demo board

The LTC7130 has a nice demo board, the DC2341A. See the 20A buck below with mΩ inductor DCR sensing with an input range of 4.5V to 20V and a Vout of 1.5V@20A.

Figure 2: The LTC7130's demo board, the DC2341A.

Thermal performance

The DC2341A demo board has a really good thermal design. See figure below.

Figure 3: The DC2341A demo board design

Figure 3: Thermal derating has been shown to be excellent both with and without airflow and heatsinks.

Package, grades and pricing

The IC is available in a thermally-enhanced 6.25×7.5×2.22mm BGA package, with both RoHS lead-free and leaded SnPb (63/37) finishes. The E-and I-grades are guaranteed from –40°C to 125°C operating junction temperature range. The 1,000-piece price starts at $7.95 each for the E grade (Pricing is for budgetary use only and may differ due to local duties, taxes, fees and exchange rates.)