The LM1771UMM device is an efficient synchronous buck switching controller with a precision enable requiring no external compensation. The constant ON-time control scheme provides a simple design free of compensation components, allowing minimal component count and board space. The precision enable pin allows flexibility in sequencing multiple rails and setting UVLO. The LM1771UMM also incorporates a unique input feedforward to maintain a constant frequency independent of the input voltage. The LM1771UMM is optimized for a low-voltage input range of 2.8 V to 5.5 V and can provide an adjustable output as low as 0.8 V. Driving an external high-side PFET and low-side NFET, it can provide efficiencies as high as 95%.
Three versions of the LM1771UMM are available depending on the switching frequency desired for the application. Nominal switching frequencies are in the range of 100 kHz to 1000 kHz.
Feature
- Input Voltage Range of 2.8 V to 5.5 V
- 0.8-V Reference Voltage
- Precision Enable
- No Compensation Required
- Constant Frequency Across Input Range
- Low Quiescent Current of 400 μA
- Internal Soft-Start
- Short Circuit Protection
- 6-Pin WSON Package and 8-Pin VSSOP Package
