Features

• Wide V_IN Range: 4V to 60V (65V Abs Max)
• Low Operating I_Q: 50μA (One Channel On)
• Wide Output Voltage Range: 0.8V ≤ V_OUT ≤ 24V
• R_SENSE or DCR Current Sensing
• Out-of-Phase Controllers Reduce Input Capacitance and Power Supply Induced Noise
• Phase-Lockable Frequency (75kHz to 850kHz)
• Programmable Fixed Frequency (50kHz to 900kHz)
• Selectable Continuous, Pulse-Skipping or Low Ripple Burst Mode® Operation at Light Loads
• Selectable Current Limit
• Very Low Dropout Operation: 99% Duty Cycle
• Adjustable Output Voltage Soft-Start or Tracking
• Power Good Output Voltage Monitors
• Low Shutdown I_Q : < 14μA
• Internal LDO Powers Gate Drive from V_IN or EXTV_CC
• Small Low Profile (0.75mm) 5mm × 5mm QFN Package

Typical Application

Description

The LTC®3890-2 is a high performance dual step-down switching regulator DC/DC controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phaselockable frequency of up to 850kHz. Power loss and noise due to the ESR of the input capacitor are minimized by operating the two controller output stages out-of-phase.

The 50μA no-load quiescent current extends operating run time in battery-powered systems. OPTI-LOOP® compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. A wide 4V to 60V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries.

Independent TRACK/SS pins for each controller ramp the output voltages during start-up. Current mode control limits the inductor current during short-circuit conditions. The PLLIN/MODE pin selects among Burst Mode operation, pulse-skipping mode, or continuous conduction mode at light loads. For versions with different and/or additional features, see the LTC3890 family summary, Table 1, in the Pin Functions section of this data sheet.