The LT®1777 is a Buck (step-down) regulator designed for noise sensitive applications. It contains a dI/dt limiting circuit programmed via a small external inductor in the switching path. Internal circuitry also generates controlled dV/dt ramp rates. The monolithic die includes all oscillator, control and protection circuitry. The part can accept operating input voltages as high as 48V, and contains an output switch rated at 700mA peak current. Current mode control offers excellent dynamic input supply rejection and short-circuit protection. The internal control circuitry is normally powered via the VCC pin, thereby minimizing power drawn directly from the VIN supply (see Applications Informa- tion). The fused-lead SO16 package and 100kHz switch- ing frequency allow for minimal PC board area requirements.
The LT1777 is a low‑noise, current‑mode step‑down switching regulator designed for noise‑sensitive applications. It features programmable dl/dt limiting, internally limited dV/dt, a high input voltage rating of 48 V, and a 700 mA peak switch rating. The device operates at a fixed 100 kHz frequency and can be synchronized up to 250 kHz.
The datasheet includes absolute maximum ratings, electrical characteristics, pin descriptions, typical performance graphs, package dimensions, and example circuit applications. It also lists related Linear Technology parts and provides mechanical drawing information for the 16‑lead plastic SO package.
| Maximum Input Voltage | 48 V |
|---|---|
| Peak Switch Current Rating | 700 mA |
| Fixed Switching Frequency | 100 kHz |
| Synchronizable Frequency Range | up to 250 kHz |
| Shutdown Mode Supply Current | 30 µA |
| Shutdown Mode Threshold Voltage | 0.5 V |
| Package Type | 16‑lead plastic SO |
The LT1777 can tolerate an input voltage up to 48 V.
The output switch is rated for a peak current of 700 mA.
The device operates at a fixed 100 kHz switching frequency, which can be synchronized up to 250 kHz.
In shutdown mode the supply current is about 30 µA.