LTC3850 Series

Dual, 2-Phase Synchronous Step-Down Switching Controller

Catalog

Dual, 2-Phase Synchronous Step-Down Switching Controller

Part	Duty Cycle (Max)	Topology	Frequency - Switching [Max]	Frequency - Switching [Min]	Voltage - Supply (Vcc/Vdd) [Min]	Voltage - Supply (Vcc/Vdd) [Max]	Supplier Device Package	Output Configuration	Function	Output Type	Output Phases	Operating Temperature [Max]	Operating Temperature [Min]	Control Features	Mounting Type	Number of Outputs	Package / Case
Analog Devices LTC3850EGN#PBF	97.2 %	Buck	780 kHz	250 kHz	4 V	24 V	28-SSOP	Positive	Step-Down	Transistor Driver	2	85 °C	-40 °C	Current Limit Enable Frequency Control Power Good Soft Start Tracking	Surface Mount	2	28-SSOP
Analog Devices LTC3850EUFD#PBF	97.2 %	Buck	780 kHz	250 kHz	4 V	24 V	28-QFN (4x5)	Positive	Step-Down	Transistor Driver	2	85 °C	-40 °C	Current Limit Enable Frequency Control Power Good Soft Start Tracking	Surface Mount	2	28-WFQFN Exposed Pad
Analog Devices LTC3850IUFD#PBF	97.2 %	Buck	780 kHz	250 kHz	4 V	30 V	28-QFN (4x5)	Positive	Step-Down	Transistor Driver	2	85 °C	-40 °C	Current Limit Enable Frequency Control Power Good Soft Start Tracking	Surface Mount	2	28-WFQFN Exposed Pad
Analog Devices LTC3850IGN#TRPBF	97.2 %	Buck	780 kHz	250 kHz	4 V	30 V	28-SSOP	Positive	Step-Down	Transistor Driver	2	85 °C	-40 °C	Current Limit Enable Frequency Control Power Good Soft Start Tracking	Surface Mount	2	28-SSOP
Analog Devices LTC3850EUF#PBF	97.2 %	Buck	780 kHz	250 kHz	4 V	24 V	28-QFN (4x4)	Positive	Step-Down	Transistor Driver	2	85 °C	-40 °C	Current Limit Enable Frequency Control Power Good Soft Start Tracking	Surface Mount	2	28-WFQFN Exposed Pad
Analog Devices LTC3850EUF#TRPBF	97.2 %	Buck	780 kHz	250 kHz	4 V	24 V	28-QFN (4x4)	Positive	Step-Down	Transistor Driver	2	85 °C	-40 °C	Current Limit Enable Frequency Control Power Good Soft Start Tracking	Surface Mount	2	28-WFQFN Exposed Pad
Analog Devices LTC3850IGN-1#PBF	97.2 %	Buck	780 kHz	250 kHz	4 V	30 V	28-SSOP	Positive	Step-Down	Transistor Driver	2	85 °C	-40 °C	Current Limit Enable Frequency Control Power Good Soft Start Tracking	Surface Mount	2	28-SSOP
Analog Devices LTC3850EUFD#TRPBF	97.2 %	Buck	780 kHz	250 kHz	4 V	24 V	28-QFN (4x5)	Positive	Step-Down	Transistor Driver	2	85 °C	-40 °C	Current Limit Enable Frequency Control Power Good Soft Start Tracking	Surface Mount	2	28-WFQFN Exposed Pad
Analog Devices LTC3850IGN-1#TRPBF	97.2 %	Buck	780 kHz	250 kHz	4 V	30 V	28-SSOP	Positive	Step-Down	Transistor Driver	2	85 °C	-40 °C	Current Limit Enable Frequency Control Power Good Soft Start Tracking	Surface Mount	2	28-SSOP

Catalog

Dual, 2-Phase Synchronous Step-Down Switching Controller

Key Features

• Dual, 180° Phased Controllers Reduce Required Input Capacitance and Power Supply Induced Noise

• High Efficiency: Up to 95%

• RSENSEor DCR Current Sensing

• ±1% 0.8V Output Voltage Accuracy

• Phase-Lockable Fixed Frequency 250kHz to 780kHz

• Supports Pre-Biased Output

• Dual N-Channel MOSFET Synchronous Drive

• Wide VINRange: 4V to 24V (30V for LTC3850I) Operation

• Adjustable Soft-Start Current Ramping or Tracking

• Foldback Output Current Limiting

• Power Good Output Voltage Monitor

• 28-Pin 4mm × 4mm, 4mm × 5mm QFN and Narrow SSOP Packages

• AEC-Q100 Qualified for Automotive Applications

Description

The LTC3850 is a high performance dual synchronous step-down switching regulator controller that drives all N-channel power MOSFET stages. A constant-frequency current mode architecture allows a phase-lockable frequency of up to 780kHz. Power loss and supply noise are minimized by operating the two controller output stages out of phase.OPTI-LOOP®compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3850 features a precision 0.8V reference and a power good output indicator. A wide 4V to 24V (28V maximum/30V for LTC3850I) input supply range encompasses most battery chemistries and intermediate bus voltages.Independent TK/SS pins for each controller ramp the output voltages during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The MODE/PLLIN pin selects among Burst Mode®operation, pulse-skipping mode, or continuous inductor current mode and allows the IC to be synchronized to an external clock.The LTC3850 is available in low profile 28-pin 4mm × 4mm, 4mm × 5mm QFN and narrow SSOP packages.FeaturesLTC3850SSOP-28 and QFN-28 PackagesLTC3850-1ILIM function replaced with an EXTVCC function, SSOP-28 package onlyLTC3850-2The LTC3850-2 is identical to the LTC3850-1 SSOP-28, except they have different pin-outsApplicationsNotebook and Palmtop ComputersPortable InstrumentsBattery-Operated Digital DevicesDC Power Distribution Systems