Linear Technology Corporation is offering two new 60 V, 200 kHz step-down dc/dc converters suited for automotive applications. The LT3437, which can accommodate transients up to 80 V, features a 500 mA, 0.8 Ohm internal switch that can deliver up to 400 mA of continuous output current at voltages as low as 1.25 V. The "H-grade" version of Linear Technology’s LT1976 operates up to a junction temperature of 140 °C, compared to the "E" and "I" grade versions' 125 °C maximum junction temperature.
A 3.3 V to 60 V input voltage range enables the LT3437 to handle load dump or cold-crank conditions in automotive applications. Burst mode operation enables quiescent current under 100 µA and suits the device for automotive and other applications that demand always-on operation and optimum battery life.
The internal switch in the LT3437 integrates oscillator, control and logic circuitry into a single die. Special design techniques and a high-voltage process enable high efficiency over a wide input voltage range and current mode topology enables fast transient response and excellent loop stability, according to the company. Other features include external synchronization (from 240 kHz to 700 kHz), soft-start capability and burst mode defeat for low noise applications. The LT3437 is available in a 3 mm x 3 mm DFN package or a thermally enhanced TSSOP-16E.
The "H-Grade" version of the LT1976 also has a 3.3 V to 60 V input voltage range. Its 1.5 A internal switch can deliver up to 1.25 A of continuous output current at voltages as low as 1.25 V.