The LT1619 is a low voltage current mode PWM controller designed for implementing current mode DC/DC converters with minimum external parts. It operates with input voltages ranging from 1.9V to 18V and is suitable for a variety of battery-powered and distributed DC/DC converters. The controller features an internal rail-to-rail N-channel MOSFET driver that can operate either from the input in the nonbootstrapped mode or from the output in bootstrapped operation. It is designed to drive a low side power transistor in boost, SEPIC, flyback, and other topologies. The converter efficiency is improved at heavy loads with a 53mV current sense voltage and at light load with Burst Mode operation. The operating frequency is internally set at 300kHz and can be externally synchronized up to 500kHz. The LT1619 is available in 8-lead MSOP and SO packages with a no load quiescent current of 140µA and a shutdown current of 15µA.
The LT1619 PWM controller implements current‑mode control for a variety of DC‑DC converter topologies, including boost, SEPIC and flyback. It operates from 1.9 V to 18 V input, provides a rail‑to‑rail N‑channel MOSFET driver, and features internal current‑sense amplification with a 53 mV limit threshold.
The device includes an external synchronization pin (S/S) for up to 500 kHz sync, burst‑mode operation for light‑load efficiency, and a shutdown pin with a 0.45 V threshold. Detailed electrical characteristics, pin functions, and typical application schematics are provided for designers.
| Input Voltage Range | 1.9 V to 18 V |
|---|---|
| Current Limit Threshold | 53 mV |
| Quiescent Supply Current (idle) | 140 µA |
| Shutdown Supply Current | 15 µA |
| Maximum Duty Cycle (typical) | 92 % |
| Undervoltage Lockout Threshold | 1.65 V (typical) |
The LT1619 operates with an input voltage from 1.9 V up to 18 V.
An external pulse can be applied to the S/S pin (Pin 1) to synchronize the internal oscillator, with allowable rise times listed in Table 1.
The internal current‑sense threshold is set at 53 mV.