7.1 Overview

The LMZ34202 is a full featured 42-V input, 2-A, synchronous step down converter with PWM, MOSFETs, inductor, and control circuitry integrated into a low-profile, overmolded package. This device enables small designs by integrating all but the input and output capacitors, while still leaving the ability to adjust key parameters to meet specific design requirements. The LMZ34202 provides a 3× output voltage range of 2.5 V to 7.5 V. A single external resistor is used to adjust the output voltage to the desired output. The switching frequency is also adjustable by using an external resistor or a synchronization pulse to accommodate various input and output voltage conditions and to optimize efficiency. The device provides accurate voltage regulation for a variety of loads by using an internal voltage reference that is 2% accurate over temperature. Input under-voltage lockout is internally set at 3.2 V, but can be adjusted upward using a resistor divider on the INH/UVLO pin of the device. The INH/UVLO pin can also be pulled low to put the device in standby mode to reduce input quiescent current. The device provides a power good signal to indicate when the output is within ±5% of its nominal voltage. Thermal shutdown and current limit features protect the device during an overload condition. Automatic PFM mode improves light-load efficiency. A 43-pin, QFN, package that includes exposed bottom pads provides a thermally enhanced solution for space-constrained applications.