LTC1735-1 Series

High Efficiency Synchronous Step-Down Switching Regulator

Catalog

High Efficiency Synchronous Step-Down Switching Regulator

Part	Mounting Type	Output Type	Supplier Device Package	Topology	Number of Outputs	Package / Case	Package / Case [x]	Package / Case [y]	Voltage - Supply (Vcc/Vdd) [Min]	Voltage - Supply (Vcc/Vdd) [Max]	Control Features	Output Configuration	Output Phases	Operating Temperature [Min]	Operating Temperature [Max]	Duty Cycle (Max) [Max]	Frequency - Switching	Function	Package / Case	Package / Case
Analog Devices LTC1735CS-1#TRPBF	Surface Mount	Transistor Driver	16-SO	Buck	1	16-SOIC	0.154 in	3.9 mm	3.5 V	30 V	Enable Power Good Soft Start	Positive	1	0 °C	85 C	99.4 %	300 kHz	Step-Down
Analog Devices LTC1735CF	Surface Mount	Transistor Driver	20-TSSOP	Buck	1	20-TSSOP	0.173 in	4.4 mm	4 V	30 V	Enable Power Good Soft Start	Positive	1	0 °C	85 C	99.4 %	300 kHz	Step-Down
Analog Devices LTC1735IS-1#PBF	Surface Mount	Transistor Driver	16-SO	Buck	1	16-SOIC	0.154 in	3.9 mm	3.5 V	30 V	Enable Power Good Soft Start	Positive	1	-40 °C	85 °C	99.4 %	300 kHz	Step-Down
Analog Devices LTC1735IGN#TRPBF	Surface Mount	Transistor Driver	16-SSOP	Buck	1	16-SSOP			4 V	30 V	Enable Power Good Soft Start	Positive	1	-40 °C	85 °C	99.4 %	300 kHz	Step-Down	0.154 in	3.9 mm
Analog Devices LTC1735CGN#TRPBF	Surface Mount	Transistor Driver	16-SSOP	Buck	1	16-SSOP			4 V	30 V	Enable Power Good Soft Start	Positive	1	0 °C	85 C	99.4 %	300 kHz	Step-Down	0.154 in	3.9 mm
Analog Devices LTC1735IGN-1#TRPBF	Surface Mount	Transistor Driver	16-SSOP	Buck	1	16-SSOP			3.5 V	30 V	Enable Power Good Soft Start	Positive	1	-40 °C	85 °C	99.4 %	300 kHz	Step-Down	0.154 in	3.9 mm
Analog Devices LTC1735CF#TRPBF	Surface Mount	Transistor Driver	20-TSSOP	Buck	1	20-TSSOP	0.173 in	4.4 mm	4 V	30 V	Enable Power Good Soft Start	Positive	1	0 °C	85 C	99.4 %	300 kHz	Step-Down
Analog Devices LTC1735IF#PBF	Surface Mount	Transistor Driver	20-TSSOP	Buck	1	20-TSSOP	0.173 in	4.4 mm	4 V	30 V	Enable Power Good Soft Start	Positive	1	-40 °C	85 °C	99.4 %	300 kHz	Step-Down
Analog Devices LTC1735CGN#PBF	Surface Mount	Transistor Driver	16-SSOP	Buck	1	16-SSOP			4 V	30 V	Enable Power Good Soft Start	Positive	1	0 °C	85 C	99.4 %	300 kHz	Step-Down	0.154 in	3.9 mm
Analog Devices LTC1735CS-1#PBF	Surface Mount	Transistor Driver	16-SO	Buck	1	16-SOIC	0.154 in	3.9 mm	3.5 V	30 V	Enable Power Good Soft Start	Positive	1	0 °C	85 C	99.4 %	300 kHz	Step-Down

Catalog

High Efficiency Synchronous Step-Down Switching Regulator

Key Features

• Synchronizable/Programmable Fixed Frequency

• OPTI-LOOP™Compensation Minimizes COUT

• ±1% Output Voltage Accuracy

• Dual N-Channel MOSFET Synchronous Drive

• Wide VINRange: 4V to 36V Operation

• VOUTRange: 0.8V to 6V

• Internal Current Foldback

• Output Overvoltage Crowbar Protection

• Latched Short-Circuit Shutdown Timer with Defeat Option

• Very Low Dropout Operation: 99% Duty Cycle

• Forced Continuous Control Pin

• Optional Programmable Soft-Start

• Remote Output Voltage Sense

• Power Good Output (LTC1735F Only)

• Logic Controlled Micropower Shutdown: IQ< 25µA

• LTC1435 Pin Compatible with Minor Component Changes

• Available in 16-Lead Narrow SSOP, SO Packages and 20-Lead TSSOP Package (LTC1735F Only)

Description

The LTC1735 is a synchronous step-down switching regulator controller that drives external N-channel power MOSFETs using a fixed frequency architecture. Burst Mode operation provides high efficiency at low load currents. The precision 0.8V reference is compatible with future generation microprocessors. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values.The operating frequency (synchronizable up to 500kHz) is set by an external capacitor allowing maximum flexibility in optimizing efficiency. A forced continuous control pin reduces noise and RF interference and can assist secondary winding regulation by disabling Burst Mode operation when the main output is lightly loaded.Protection features include internal foldback current limiting, output overvoltage crowbar and optional short-circuit shutdown. Soft-start is provided by an external capacitor that can be used to properly sequence supplies. The operating current level is user-programmable via an external current sense resistor. Wide input supply range allows operation from 4V to 30V (36V maximum).FeaturesLTC1735-LTC1735-1Power GoodApplicationsNotebook and Palmtop Computers, PDAsCellular Telephones and Wireless ModemsDC Power Distribution Systems