• 3.3-V and 5-V 100-mA Bootstrapped Standby Regulators with Independent Enables
• Selectable D-CAP™ Mode Enables Fast Transient Response Less than 100 ns
• Selectable Low Ripple Current Mode
• Less than 1% Internal Reference Accuracy
• Selectable PWM-only/Auto-skip Modes
• Low-side RDS(on) Loss-less Current Sensing
• RSENSE Accurate Current Sense Option
• Internal Soft-Start and Integrated VOUT Discharge Transistors
• Integrated 2-V Reference
• Adaptive Gate Drivers with Integrated Boost Diode
• Powergood for Each Channel with Delay Timer
• Fault Disable Mode
• Supply Input Voltage Range: 4.5 V to 28 V

Notebook Computers System Bus and I/O

The TPS51120 is a highly sophisticated dual, synchronous step-down controller. It is a full featured controller designed to run directly off a three- or four-cell Li-ion battery and provide high-power and 5-V and/or 3.3-V standby regulation for all the downstream circuitry in a notebook computer system. High-current, 100-mA, 5-V or 3.3-V on-board linear regulators have glitch-free switch over function to SMPS and can be kept alive independently during standby state. The pseudo-constant frequency adaptive on-time control scheme supports full range of current mode operation including simplified loop compensation, ceramic output capacitors as well as seamless transition to reduced frequency operation at light-load condition. Optional D-CAP mode operation optimized for SP-CAP or POSCAP output capacitors allows further reduction of external compensation parts. Dynamic UVP supports VIN line sag without latch off by hitting 5-V UVP. No negative voltage appears at output voltage node during UVLO, UVP, and OCP, OTP or loss of VIN.

The TPS51120 32-pin QFN package is specified from –40°C to 85°C ambient temperature.