Features

• Dual, 180° Phased Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
• Tracking for Both Outputs
• Constant Frequency Current Mode Control
• Wide V_IN Range: 4.5V to 28V Operation
• Power Good Output Voltage Indicator
• Adjustable Soft-Start Current Ramping
• Foldback Output Current Limiting- Disabled at Start-Up
• No Reverse Current During Soft-Start Interval
• Clock Output for 3-, 4-, 6-Phase Operation
• Dual N-Channel MOSFET Synchronous Drive
• ±1% Output Voltage Accuracy
• Phase-Lockable Fixed Frequency 260kHz to 550kHz
• OPTI-LOOP® Compensation Minimizes C_OUT
• Very Low Dropout Operation: 99% Duty Cycle
• Output Overvoltage Protection
• Small 28-Lead SSOP and 5mm × 5mm QFN Packages

Typical Application

Description

The LTC3828 is a dual high performance step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages.  A constant frequency current mode architecture allows for a phase-lockable frequency of up to 550kHz.  The TRCKSS pin provides both soft-start and tracking functions.  Multiple LTC3828s can be daisy-chained in applications requiring more than two voltages to be tracked.

OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values.  The precision 0.8V reference and power good output indicator are compatible with a wide 4.5V to 28V (30V maximum) input supply range, encompassing all battery chemistries.

The RUN pins control their respective channels independently.  The FCB/PLLIN pin selects among Burst Mode operation, skip-cycle mode and continuous current mode.  Current foldback limits MOSFET dissipationduring short-circuit conditions.  Reverse current and current foldback functions are disabled during soft-start.