一,产品概述(General Description)         
      The JTM3440 is high efficiency, fixed frequency,Buck-Boost DC/DC converter that operates from input voltages above, below or equal to the output voltage. The devices are suitable for single lithium-ion, multicell alkaline or NiMH applications
where the output voltage is within the battery voltage range.The switching frequencies up to 1.5 MHz could befixed by employing an external resistor, and the
oscillator could be synchronized to an external clock. The quiescent current is 1mA, and this feature maximizing the battery life in portable applications.Other features include a 1µA shutdown, thermal shutdown and current limit. The JTM3440 is available in the 10-pin thermally enhanced MSOP packages (or upon request).

二.产品特点(Features)
Synchronous Rectification: Up to 95% Efficiency
Single Inductor
Fixed Frequency Operation with Battery
Voltages Above, Below or Equal to the Output
Quiescent Current 1mA (50uA low power mode: mode pin high)
Up to 1A Continuous Output Current
2.7V to 5.5V Input and Output Voltage range
Programmable oscillator frequency from 350kHz to 1.5MHz
No Schottky Diodes required VOUT<4.3V
VOUT Disconnected from VIN During Shutdown
1µA Shutdown Current
Package: Small Thermally Enhanced 10-pin MSOP

三,应用范围 (Applications)
Handheld Instruments
MP3/MP4 Players
Palmtop computers
Digital Cameras

四.下载产品资料PDF文档

JTM3440

五,产品封装图 (Package)

PIN NUMBER MSOP-10L	PIN NAME	FUNCTION
1	RT	Program the Oscillator Frequency
2	MODE/SYN C	Synchronization of the Internal Oscillator
3	SW1	Switch 1
4	SW2	Switch 2
5	GND	Ground
6	VOUT	Output
7	VIN	Input
8	EN	ON/OFF Control (High Enable)
9	FB	Feedback
10	VC	Error Amp Output

六.电路原理图


七,功能概述
The JTM3440 provides high efficiency, low noise power for applications such as portable instrumentation.
The JTM3440 allows input voltages above, below or equal to the output voltage by properly phasing the
output switches. The error amp output voltage on the VC pin determines the output duty cycle of the
switches.
Since the VC pin is a filtered signal, it provides rejection of frequencies from well below the switching
frequency. The low RDS(ON), low gate charge synchronous switches provide high frequency pulse width
modulation control at high efficiency.

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