LTC1778
LTC1778 is Step-Down Controller manufactured by Linear Technology.
LTC1778/LTC1778-1
Wide Operating Range, No RSENSETM Step-Down Controller
Features
- No Sense Resistor Required
- True Current Mode Control
- Optimized for High Step-Down Ratios
- t ON(MIN) ≤ 100ns
- Extremely Fast Transient Response
- Stable with Ceramic COUT
- Dual N-Channel MOSFET Synchronous Drive
- Power Good Output Voltage Monitor (LTC1778)
- Adjustable On-Time (LTC1778-1)
- Wide VIN Range: 4V to 36V
- ±1% 0.8V Voltage Reference
- Adjustable Current Limit
- Adjustable Switching Frequency
- Programmable Soft-Start
- Output Overvoltage Protection
- Optional Short-Circuit Shutdown Timer
- Micropower Shutdown: IQ < 30µA
- Available in a 16-Pin Narrow SSOP Package
U APPLICATIO S
- Notebook and Palmtop puters
- Distributed Power Systems
DESCRIPTIO
The LTC®1778 is a synchronous step-down switching regulator controller optimized for CPU power. The controller uses a valley current control architecture to deliver very low duty cycles with excellent transient response without requiring a sense resistor. Operating frequency is selected by an external resistor and is pensated for variations in VIN.
Discontinuous mode operation provides high efficiency operation at light loads. A forced continuous control pin reduces noise and RF interference, and can assist secondary winding regulation by disabling discontinuous operation when the main output is lightly loaded.
Fault protection is provided by internal foldback current limiting, an output overvoltage parator and optional short-circuit shutdown timer. Soft-start capability for supply sequencing is acplished using an external timing capacitor. The regulator current limit level is user programmable. Wide supply range allows operation from 4V to 36V at the input and from 0.8V up to (0.9)VIN at the output.
, LTC and LT are registered trademarks of Linear Technology Corporation. No RSENSE is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners....
