LM2611

1.4MHz switching frequency
Low R_DS(ON) DMOS FET
1mVp-p output ripple
−5V at 300mA from 5V input
Better regulation than a charge pump
Uses tiny capacitors and inductors
Wide input range: 2.7V to 14V
Low shutdown current: <1uA
5-lead SOT-23 package

The LM2611 is a current mode, PWM inverting switching regulator. Operating from a 2.7 - 14V supply, it is capable of producing a regulated negative output voltage of up to −(36-V_IN(MAX))_. The LM2611 utilizes an input and output inductor, which enables low voltage ripple and RMS current on both the input and the output. With a switching frequency of 1.4MHz, the inductors and output capacitor can be physically small and low cost. High efficiency is achieved through the use of a low R_DS(ON) FET.

The LM2611 features a shutdown pin, which can be activated when the part is not needed to lower the Iq and save battery life. A negative feedback (NFB) pin provides a simple method of setting the output voltage, using just two resistors. Cycle-by-cycle current limiting and internal compensation further simplify the use of the LM2611.

The LM2611 is available is a small SOT23-5 package. It comes in two grades: