MIC2172YM

Product Summary

The MIC2172YM is a complete 100kHz SMPS current-mode controller with internal 65V 1.25A power switches. It features external frequency synchronization or frequency adjustment. Although primarily intended for voltage step-up applications, the floating switch architecture of the MIC2172YM makes it practical for step-down, inverting, and Cuk configurations as well as isolated topologies. Operating from 3V to 40V, the MIC2172YM draws only 7mA of quiescent current making it attractive for battery operated supplies. For applications not requiring control, EN must be tied to VIN or TTL high. The MIC2172YM is for applications requiring two or more SMPS regulators that operate from the same input supply. It features a SYNC input which allows locking of its internal oscillator to an external reference. This makes it possible to avoid the audible beat frequencies that result from the unequal oscillator frequencies of independent SMPS regulators. A reference signal can be supplied by the MIC2172YM designated as a master. To insure locking of the slave’s oscillators, the reference oscillator frequency must be higher than the slave’s. The MIC2172YM’s oscillator frequency is increased up to 135kHz by connecting a resistor from SYNC to ground (see applications information). The MIC2172YM is available in an 8-pin plastic SOIC for –40℃ to +85℃ operation.

Parametrics

MIC2172YM absolute maximum ratings: (1)Input Voltage: 40V; (2)Switch Voltage: 65V; (3)Sync Current: 50mA; (4)Feedback Voltage (Transient, 1ms): ±15V; (5)Operating Temperature Range: –40 to +85℃; (6)Junction Temperature: –55℃ to +150℃; (7)Thermal Resistance θJA: 120℃/W; (8)Storage Temperature: –65℃ to +150℃; (9)Soldering (10 sec.): +300℃.

Features

MIC2172YM features: (1)1.25A, 65V internal switch rating; (2)3V to 40V input voltage range; (3)Current-mode operation; (4)Internal cycle-by-cycle current limit; (5)Thermal shutdown; (6)Low external parts count; (7)Operates in most switching topologies; (8)7mA quiescent current (operating); (9)External frequency synchronization; (10)External frequency trim; (11)Fits most LT1172 sockets.

Diagrams