LTC3549 250mA Low VIN Buck Regulator in 2mm x 3mm DFN

The LTC®3549 is a high efficiency, monolithic synchronous buck regulator using a constant-frequency, current mode architecture. The output voltage is adjusted via an external resistor divider.

A fixed switching frequency of 2.25MHz is supported. This switching frequency allows the use of small surface mount inductors and capacitors, including ceramics.

Supply current during Burst Mode operation is only 50µA dropping to < 1µA in shutdown. The 1.6V to 5.5V input voltage range makes the LTC3549 ideally suited for single cell Li-Ion, Li-Metal and 2-cell alkaline, NiCd or NiMH battery-powered applications. 100% duty cycle capability provides low dropout operation, extending battery life in portable systems. Burst Mode operation can be user-enabled, increasing efficiency at light loads, further extending battery life.

The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. Internal soft-start offers controlled output voltage rise time at startup without the need for external components

产品特点 Features

1.6V to 5.5V Input Voltage Range
Internal Soft-Start
Low Ripple Burst Mode® Operation
Output Ripple: <20mVP-P
IQ: 50µA
2.25MHz Constant-Frequency Operation
High Efﬁ ciency: Up to 93%
250mA Output Current (VIN = 1.8V, VOUT = 1.2V)
450mA Peak Inductor Current
No Schottky Diode Required
Low Dropout Operation: 100% Duty Cycle
0.611V Reference Voltage
Stable with Ceramic Capacitors
Shutdown Mode Draws <1µA Supply Current
Current Mode Operation for Excellent Line and Load Transient Response
Overtemperature Protection
Available in a Low Proﬁ le (0.75mm) 6-Lead (2mm x 3mm) DFN Package

应用

2 AA-Cell Applications
Cellular Phones
Digital Cameras
MP3 Players

典型应用图

参数

LTC3549 订购信息和价格参考Package Variations and Pricing

器件型号	封装	引脚	温度	价格 (以 1 ~ 99 片为批量)	价格 (以 1000 片为批量) *
LTC3549EDCB#PBF	DFN	6	E	$2.06
LTC3549EDCB#TRMPBF	DFN	6	E	$2.06	$1.49
LTC3549EDCB#TRPBF	DFN	6	E	$2.06	$1.44

LTC3549 数据手册及相关资料下载

数据手册(英文) : LTC3549 - 250mA Low VIN Buck Regulator in 2mm x 3mm DFN.PDF
产品选型卡 : Energy Harvesting Portfolio.PDF
可靠性数据 : R415 Reliability Data .PDF