The document introduces MIC2172 and MIC3172, two 100kHz 1.25A switching regulators. The features of these two products are internal 65V 1.25A power switches, external frequency synchronization or frequency adjustment, and enable/shutdown control input. Although these two products are mainly used for voltage step-up applications, their floating switch architecture makes them practical for step-down, inverting, and Cuk configurations as well as isolated topologies. MIC2172/3172 operates from 3V to 40V and draws only 7mA of quiescent current, making it attractive for battery operated supplies. MIC3172 is for applications that require on/off control of the regulator. MIC3172 is externally shutdown by applying a TTL low signal to EN (enable). When disabled, the MIC3172 draws only leakage current (typically less than 1µA). EN must be high for normal operation. For applications not requiring control, EN must be tied to VIN or TTL high. MIC2172 is for applications requiring two or more SMPS regulators that operate from the same input supply. MIC2172 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 input frequencies.
The MIC2172 and MIC3172 are current‑mode switching regulator controllers that operate at 100 kHz and include an internal 65 V, 1.25 A power switch. They support a wide input voltage range (3 V to 40 V) and draw only 7 mA quiescent current in normal operation, making them suitable for battery‑powered designs. The MIC2172 adds an external SYNC input for frequency synchronization, while the MIC3172 provides an enable/shutdown pin.
Both devices are offered in 8‑pin plastic DIP and SOIC packages and are rated for –40 °C to +85 °C operation. The datasheet includes pin descriptions, absolute maximum ratings, electrical characteristics, typical performance curves, and package dimensions.
| Input voltage range | 3 V – 40 V |
|---|---|
| Internal switch rating | 1.25 A, 65 V |
| Quiescent current (operating) | 7 mA |
| Operating temperature range | -40 °C to +85 °C |
| Oscillator frequency (free‑running) | ≈100 kHz |
| Maximum sync frequency (MIC2172) | up to 135 kHz |
| Package options | 8‑pin plastic DIP or 8‑pin SOIC |
The devices operate from 3 V up to 40 V input voltage.
The MIC2172 is offered in an 8‑pin plastic DIP and an 8‑pin SOIC package.
The regulator draws about 7 mA of quiescent current while operating.
A SYNC input can be capacitively coupled to a reference signal higher than the device’s free‑running frequency, locking the oscillator up to 135 kHz.