Linear Technology Corporation introduces 42V, high-efficiency, dual-channel, synchronous single-chip step-down switching regulators

     Linear Technology Corporation introduces the LT8616, a 42V, high-efficiency, dual-channel, synchronous single-chip step-down switching regulator. The regulator comes in a heat-resistant enhanced 28-lead TSSOP package. There are three temperature grade versions available, the Extended (E) and Industrial (I) grade versions operating in the -40 °C to 125°C (junction temperature) temperature range, and the high temperature (H) grade versions operating in the -40 °C to 150°C temperature range.

     Its dual-channel design provides independent 2.5A and 1.5A continuous currents to outputs as low as 0.8V. The dual-channel synchronous rectification topology provides up to 95% efficiency, and with no load backup, Burst Mode® operation keeps the static current below 6.5µA (two-channel start), making the device ideal for altime-on-connected systems. The switching frequency can be set in the range of 200kHz to 3MHz, and can be synchronized in this range.

     The LT8616's 35ns minimum on-time enables a depressury-type conversion from 16VIN to 1.8VOUT, while the 2MHz switch helps designers avoid critical noise sensitive bands, such as AM radios, while keeping the solution's board area very compact. The device's input voltage range of 3.4V to 42V makes it ideal for automotive applications, which must be stable under cold car start and stop-start conditions with minimum input voltage down to 3.4V, and during load drop transients in excess of 40V. In all cases, the LT8616 maintains a minimum low-voltage differential voltage of only 400mV (at 1A) per channel, enabling the device to perform well in situations such as cold car start-up. The LT8616's 28-lead heat-enhanced TSSOP package and high switching frequency allow the use of small external inductors and capacitors for a compact and thermally efficient solution.

     The LT8616 features two internal up-tube and down-tube high-efficiency power switches that integrate the necessary boost diodes, oscillators, control and logic circuits in a single chip. Each channel operates on a 180-degree out-of-phase switch, reducing output ripple. Each channel has a separate input to increase design flexibility. Low Ripple burst mode operation maintains high efficiency at low output currents while keeping the output ripple below 15mVP-P. The unique design approach and new high-speed process enable the device to achieve high efficiency over a wide range of input voltages, and the LT8616's current mode topology provides fast transient response and excellent loop stability. Other features include internal compensation, well-marked power supply, output soft start/tracking, and overheat protection.