The LMZM23601 power module utilizes peak-current-mode-control architecture. This enables the use of wide range of input voltages while maintaining constant switching frequency and good input and output transient response. The device can be used with 5-V, 12-V, or 24-V typical industrial input voltage rail. The short minimum on- and off-times ensure constant frequency regulation over a wide range of input to output voltage conversion ratios. The adjustable (ADJ) output voltage option operates at 1000-kHz switching frequency. The minimum on- and off- times allow for a duty factor window of 5% to 91% at 1000-kHz switching frequency. If the input voltage exceeds approximately 28 V on the ADJ version, the frequency is smoothly reduced from 1000 kHz as a function of input voltage. The switching frequency reduction allows output voltage regulation and the current mode control to operate with a duty factor below 5%. The fixed 5-V and 3.3-V output options operate at 750 kHz nominal switching frequency and the frequency foldback at high input voltage is not active or needed.

The control architecture also uses frequency foldback at low input voltage to achieve low dropout voltage, maintaining output regulation as the input voltage falls close to output voltage. The frequency foldback at low input voltage is active for the ADJ as well as the 5-V and 3.3-V output options. The reduction in frequency is smooth and continuous and is activated as the off-time approaches the minimum value. Under these conditions, the LMZM23601 device operates much like a constant off-time converter allowing the maximum duty cycle to reach 97%. This feature allows output voltage regulation with very low dropout.

The LMZM23601 features exceptional conversion efficiency at light load. As the load current is reduced, the LMZM23601 transitions to light-load mode if the MODE/SYNC terminal is pulled low. In light-load mode the device uses diode emulation to reduce the RMS inductor current and the switching frequency is reduced. The fixed voltage versions (3.3-V and 5-V) do not need an external voltage divider connected to FB, which results in saving two components and lower standby current when the load is in standby. As a result, the consumed supply current is only 24 μA (typical) with 24-V to 3.3-V conversion and 28 μA (typical) with 24-V to 5-V conversion, while the output is regulated with no load.