The LTC1622 is a constant frequency current mode step-down DC/DC controller providing excellent AC and DC load and line regulation. The device incorporates an accurate undervoltage feature that shuts the LTC1622 down when the input voltage falls below 2V. The LTC1622 boasts a ±1.9% output voltage accuracy and consumes only 350µA of quiescent current. For applications where efficiency is a prime consideration and the load current varies from light to heavy, the LTC1622 can be configured for Burst Mode TM operation. Burst Mode operation enhances low current efficiency and extends battery run time. Burst Mode operation is inhibited during synchronization or when the SYNC/MODE pin is pulled low to reduce noise and possible RF interference. High constant operating frequency of 550kHz allows the use of a small inductor. The device can also be synchronized up to 750kHz for special applications. The high frequency operation and the available 8-lead MSOP package create a high performance solution in an extremely small amount of PCB area. To further maximize the life of the battery source, the P-channel MOSFET is turned on continuously in dropout (100% duty cycle). In shutdown, the device draws a mere 15µA.
This handbook introduces the LTC1622 constant‑frequency current‑mode step‑down DC/DC controller. It lists key features such as high efficiency, 550 kHz operation, 2 V‑10 V input range, multi‑ampere output, low quiescent current (350 pA) and optional burst‑mode operation.
The document provides electrical characteristics, absolute maximum ratings, pin descriptions, functional diagrams, and design guidance for selecting external components such as the sense resistor, inductor, MOSFET and output diode. Typical applications, performance graphs, and package dimensions are also included.
| Input Voltage Range | 2 V to 10 V |
|---|---|
| Operating Frequency | 550 kHz (typical), up to 750 kHz sync |
| Quiescent Current | 350 pA |
| Shutdown Mode Current | 15 µA |
| Output Voltage Accuracy | +1.9 % (typical) |
The LTC1622 operates with an input voltage from 2 V to 10 V.
The LTC1622 draws only 350 pA of quiescent current.
In shutdown mode the device draws about 15 µA.