LTC3868-1 Series

Low IQ, Dual 2-Phase Synchronous Step-Down Controller

Catalog

Low IQ, Dual 2-Phase Synchronous Step-Down Controller

Part	Output Type	Control Features	Function	Output Configuration	Number of Outputs	Operating Temperature [Max]	Operating Temperature [Min]	Topology	Supplier Device Package	Output Phases	Mounting Type	Voltage - Supply (Vcc/Vdd) [Min]	Voltage - Supply (Vcc/Vdd) [Max]	Duty Cycle (Max) [Max]	Frequency - Switching [Max]	Frequency - Switching [Min]	Package / Case
Analog Devices LTC3868IUH#PBF	Transistor Driver	Current Limit Enable Frequency Control Phase Control Power Good Soft Start	Step-Down	Positive	2	85 °C	-40 °C	Buck	32-QFN (5x5)	2	Surface Mount	4 V	24 V	99.4 %	535 kHz 835 kHz	105 kHz 350 kHz
Analog Devices LTC3868EUFD-1#TRPBF	Transistor Driver	Enable Frequency Control Power Good Soft Start	Step-Down	Positive	2	85 °C	-40 °C	Buck	28-QFN (4x5)	2	Surface Mount	4 V	24 V	99.4 %	535 kHz 835 kHz	105 kHz 350 kHz	28-WFQFN Exposed Pad
Analog Devices LTC3868EUH#TRPBF	Transistor Driver	Current Limit Enable Frequency Control Phase Control Power Good Soft Start	Step-Down	Positive	2	85 °C	-40 °C	Buck	32-QFN (5x5)	2	Surface Mount	4 V	24 V	99.4 %	535 kHz 835 kHz	105 kHz 350 kHz
Analog Devices LTC3868IGN-1#PBF	Transistor Driver	Enable Frequency Control Power Good Soft Start	Step-Down	Positive	2	85 °C	-40 °C	Buck	28-SSOP	2	Surface Mount	4 V	24 V	99.4 %	535 kHz 835 kHz	105 kHz 350 kHz	28-SSOP
Analog Devices LTC3868EUFD-1#PBF	Transistor Driver	Enable Frequency Control Power Good Soft Start	Step-Down	Positive	2	85 °C	-40 °C	Buck	28-QFN (4x5)	2	Surface Mount	4 V	24 V	99.4 %	535 kHz 835 kHz	105 kHz 350 kHz	28-WFQFN Exposed Pad

Catalog

Low IQ, Dual 2-Phase Synchronous Step-Down Controller

Key Features

• Low Operating IQ: 170μA (One Channel On)

• Wide Output Voltage Range: 0.8V ≤ VOUT≤ 14V

• Wide VINRange: 4V to 24V

• RSENSEor DCR Current Sensing

• Out-of-Phase Controllers Reduce Required Input Capacitance and Power Supply Induced Noise

• OPTI-LOOP®Compensation Minimizes COUT

• Phase-Lockable Frequency (75kHz to 850kHz)

• Programmable Fixed Frequency (50kHz to 900kHz)

• Selectable Continuous, Pulse-Skipping or Burst Mode®Operation at Light Loads

• Very Low Dropout Operation: 99% Duty Cycle

• Adjustable Output Voltage Soft-Start

• Power Good Output Voltage Monitor

• Output Overvoltage Protection

• Output Latchoff Protection During Short Circuit

• Low Shutdown IQ: 8μA

• Internal LDO Powers Gate Drive from VINor EXTVCC

• No Current Foldback During Start-Up

• Small 4mm × 5mm QFN and Narrow SSOP Packages

Description

The LTC3868-1 is a high performance dual step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phase-lockable frequency of up to 850kHz. Power loss and noise due to the input capacitor ESR are minimized by operating the two controller outputs out of phase.The 170μA no-load quiescent current extends operating life in battery powered systems. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3868-1 features a precision 0.8V reference and a power good output indicator. A wide 4V to 24V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries.Independent soft-start pins for each controller ramp the output voltages during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The output short-circuit latchoff feature further protects the circuit in short-circuit conditions.For a leadless 32-pin QFN package with the additional features of adjustable current limit, clock out, phase modulation and two PGOOD outputs, see the LTC3868 data sheet.LTC3868LTC3868-1FeaturesAdjustable Current Limit, Clock Out Pin, Phase Modulation, Two PGOODFixed Current Limit, One PGOODPackageQFN-32SSOP-28ApplicationsNotebook and Palmtop ComputersPortable InstrumentsBattery Operated Digital DevicesDistributed DC Power Systems