CXSD6257 300KHz fixed frequency PWM buck (step-down) DC/DC converter 4A load with high efficiency Wide 5V to 32V Input Voltage Range

Time of publication：2020-04-13Number of views：58

目录1.产品概述 2.产品特点 3.应用范围      4.技术规格书下载（产品PDF文档） iFU嘉泰姆
5.产品封装图 6.电路原理图 7.功能概述 8.相关产品iFU嘉泰姆
一,产品概述(General Description)      iFU嘉泰姆
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  The CXSD6257 is a 300KHz fixed frequency PWM buck (step-down)iFU嘉泰姆
DC/DC converter,capable of driving a 4A load with high efficiency, lowiFU嘉泰姆
ripple and excellent line and load regulation.Requiring a minimum numberiFU嘉泰姆
of external components, the regulator is simple to use and include internal iFU嘉泰姆
frequency compensation and a fixed-frequency oscillator. iFU嘉泰姆
The PWM control circuit is able to adjust the duty ratio linearly from 0 toiFU嘉泰姆
100%. An enable function, an over current protection function is built inside.iFU嘉泰姆
When short protection function happens, the operation frequency will beiFU嘉泰姆
reduced from 300KHz to 60KHz. An internal compensation block is built in to minimize external component count.iFU嘉泰姆
二.产品特点(Features)iFU嘉泰姆
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Wide 5V to 32V Input Voltage RangeiFU嘉泰姆
Output Adjustable from 0.8V to 30ViFU嘉泰姆
Maximum Duty Cycle 100%iFU嘉泰姆
Minimum Drop Out 0.6ViFU嘉泰姆
Fixed 300KHz Switching FrequencyiFU嘉泰姆
4A Constant Output Current CapabilityiFU嘉泰姆
Internal Optimize Power MOSFETiFU嘉泰姆
High efficiencyiFU嘉泰姆
Excellent line and load regulationiFU嘉泰姆
TTL shutdown capabilityiFU嘉泰姆
EN pin with hysteresis functioniFU嘉泰姆
Built in thermal shutdown functioniFU嘉泰姆
Built in current limit functioniFU嘉泰姆
Built in output short protection functioniFU嘉泰姆
Available in TO-252 packageiFU嘉泰姆
三,应用范围 (Applications)iFU嘉泰姆
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LCD Monitor and LCD TViFU嘉泰姆
Digital Photo FrameiFU嘉泰姆
Set-up BoxiFU嘉泰姆
ADSL ModemiFU嘉泰姆
Telecom / Networking EquipmentiFU嘉泰姆

四.技术规格书下载（产品PDF）iFU嘉泰姆
iFU嘉泰姆

需要详细的PDF规格书请扫一扫微信联系我们，还可以获得免费样品以及技术支持！iFU嘉泰姆

QQ截图20160419174301.jpg iFU嘉泰姆

五,产品封装图 (Package)iFU嘉泰姆
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Pin NumberiFU嘉泰姆	Pin NameiFU嘉泰姆	DescriptioniFU嘉泰姆
1iFU嘉泰姆	GNDiFU嘉泰姆	Ground Pin. Care must be taken in layout. This pin should beiFU嘉泰姆 placed outside of the Schottky Diode to output capacitoriFU嘉泰姆 ground path to prevent switching current spikes from inducingiFU嘉泰姆 voltage noise into CXSD6257.iFU嘉泰姆
2iFU嘉泰姆	FBiFU嘉泰姆	Feedback Pin (FB). Through an external resistor divideriFU嘉泰姆 network, FB senses the output voltage and regulates it. TheiFU嘉泰姆 feedback threshold voltage is 0.8V.iFU嘉泰姆
3iFU嘉泰姆	SWiFU嘉泰姆	Power Switch Output Pin (SW). SW is the switch node thatiFU嘉泰姆 supplies power to the output.iFU嘉泰姆
4iFU嘉泰姆	ENiFU嘉泰姆	Enable Pin. Drive EN pin high to turn on the device, drive itiFU嘉泰姆 low to turn it off.iFU嘉泰姆
5iFU嘉泰姆	VINiFU嘉泰姆	Supply Voltage Input Pin. CXSD6257 operates from a 5V to 32ViFU嘉泰姆 DC voltage. Bypass Vin to GND with a suitably largeiFU嘉泰姆 capacitor to eliminate noise on the input.iFU嘉泰姆

六.电路原理图iFU嘉泰姆
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七.CXSD6257 DEMO BOARD MANUALiFU嘉泰姆
(一)CXSD6257 12V 转 5V 应用电路测试数据：iFU嘉泰姆
1． CXSD6257 12V 转 5V（负载 0.5A~4A）应用电路图：iFU嘉泰姆
2. CXSD6257 12V 转 5V（负载 0.5A~4A）测试数据及效率图：iFU嘉泰姆

输入电压（V）iFU嘉泰姆	输入电流（A）iFU嘉泰姆	输出电压（V）iFU嘉泰姆	输出电流（A）iFU嘉泰姆	效率（%）iFU嘉泰姆
11.822iFU嘉泰姆	0.242iFU嘉泰姆	5.010iFU嘉泰姆	0.5iFU嘉泰姆	87.56iFU嘉泰姆
11.648iFU嘉泰姆	0.476iFU嘉泰姆	5.007iFU嘉泰姆	1iFU嘉泰姆	90.31iFU嘉泰姆
11.476iFU嘉泰姆	0.721iFU嘉泰姆	5.007iFU嘉泰姆	1.5iFU嘉泰姆	90.77iFU嘉泰姆
11.409iFU嘉泰姆	0.967iFU嘉泰姆	5.001iFU嘉泰姆	2iFU嘉泰姆	90.66iFU嘉泰姆
11.402iFU嘉泰姆	1.217iFU嘉泰姆	4.995iFU嘉泰姆	2.5iFU嘉泰姆	89.99iFU嘉泰姆
11.341iFU嘉泰姆	1.486iFU嘉泰姆	4.991iFU嘉泰姆	3iFU嘉泰姆	88.85iFU嘉泰姆
11.296iFU嘉泰姆	1.762iFU嘉泰姆	4.982iFU嘉泰姆	3.5iFU嘉泰姆	87.61iFU嘉泰姆
11.148iFU嘉泰姆	2.052iFU嘉泰姆	4.973iFU嘉泰姆	4iFU嘉泰姆	86.96iFU嘉泰姆

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(二)CXSD6257 24V 转 12V 应用电路测试数据：iFU嘉泰姆
1．CXSD6257 24V 转 12V（负载 0.5A~4A）应用电路图：iFU嘉泰姆
2. CXSD6257 24V 转 12V（负载 0.5A~4A）测试数据及效率：iFU嘉泰姆

输入电压（V）iFU嘉泰姆	输入电流（A）iFU嘉泰姆	输出电压（V）iFU嘉泰姆	输出电流（A）iFU嘉泰姆	效率（%）iFU嘉泰姆
23.95iFU嘉泰姆	0.293iFU嘉泰姆	12.07iFU嘉泰姆	0.5iFU嘉泰姆	86.00iFU嘉泰姆
23.81iFU嘉泰姆	0.555iFU嘉泰姆	12.06iFU嘉泰姆	1iFU嘉泰姆	91.26iFU嘉泰姆
23.60iFU嘉泰姆	0.826iFU嘉泰姆	12.05iFU嘉泰姆	1.5iFU嘉泰姆	92.72iFU嘉泰姆
23.42iFU嘉泰姆	1.101iFU嘉泰姆	12.04iFU嘉泰姆	2iFU嘉泰姆	93.39iFU嘉泰姆
23.28iFU嘉泰姆	1.378iFU嘉泰姆	12.03iFU嘉泰姆	2.5iFU嘉泰姆	93.75iFU嘉泰姆
23.12iFU嘉泰姆	1.669iFU嘉泰姆	12.01iFU嘉泰姆	3iFU嘉泰姆	93.37iFU嘉泰姆
23.00iFU嘉泰姆	1.960iFU嘉泰姆	12.00iFU嘉泰姆	3.5iFU嘉泰姆	93.17iFU嘉泰姆
22.82iFU嘉泰姆	2.262iFU嘉泰姆	11.98iFU嘉泰姆	4iFU嘉泰姆	92.83iFU嘉泰姆

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(三)CXSD6257 PCB 板布局建议：iFU嘉泰姆
（1）流大电流的线要粗，短，不拐弯。iFU嘉泰姆
（2）1 脚（GND），5 脚（VIN）线要粗，短线，不拐弯，且输入电解电容 CIN 和 105 C1 陶瓷电容紧挨第 5 脚iFU嘉泰姆
（VIN）和 1 脚(GND)。（主要是为了减小输入电源布线寄生的电感，电阻产生的高压开关毛刺干扰）iFU嘉泰姆
（3）3 脚（SW）输出线要粗，短线，不拐弯，电感和续流二极管要紧挨第 3 脚（SW）输出端。iFU嘉泰姆
（4）2 脚（FB）走线要接到输出滤波电容 C2,COUT 之后, PCB 布线远离 L1,D1,避免噪声干扰。iFU嘉泰姆
（5）增加 PCB 板铜薄的厚度。（DEMO 板用 130um 厚铜薄双面 PCB 板材料）iFU嘉泰姆
（6）适当的增加 CXSD6257 芯片衬底与 PCB 板的接触面积，提高芯片散热能力，注意 CXSD6257 芯片衬底是 SW 端。CXSD6257PCB 图:iFU嘉泰姆
(四)CXSD6257 温度测试数据iFU嘉泰姆
1：CXSD6257 电路图和 PCB 图：iFU嘉泰姆
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2：CXSD6257 DEMO 板工作时（12V 转 5V）各元件温度，自然通风，室温：27℃。iFU嘉泰姆
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(五)CXSD6257 实现恒流具体方案1CXSD6257 恒流原理图iFU嘉泰姆
说明：先把 RCS 的功耗降下来，把 VRCS 放大几倍之后与 FB 关联。其中放大器iFU嘉泰姆
VAR1=VRCS(1+R6/R5) ，例如设定恒流电路单路 ICS =300mA，RCS=0.33R, 那么 VCS=RCS*ICSiFU嘉泰姆
0.099V 由于 VAR1＝0.8V 那么放大器调解成放大 8.倍，那么 R5,R6 的值就可以得出来了。iFU嘉泰姆
八,功能概述iFU嘉泰姆
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ParameteriFU嘉泰姆	SymboliFU嘉泰姆	ValueiFU嘉泰姆	UnitiFU嘉泰姆
Input VoltageiFU嘉泰姆	ViniFU嘉泰姆	-0.3 to 35iFU嘉泰姆	ViFU嘉泰姆
Feedback Pin VoltageiFU嘉泰姆	VFBiFU嘉泰姆	-0.3 to ViniFU嘉泰姆	ViFU嘉泰姆
EN Pin VoltageiFU嘉泰姆	VENiFU嘉泰姆	-0.3 to ViniFU嘉泰姆	ViFU嘉泰姆
Output Switch Pin VoltageiFU嘉泰姆	VOutputiFU嘉泰姆	-0.3 to ViniFU嘉泰姆	ViFU嘉泰姆
Power DissipationiFU嘉泰姆	PDiFU嘉泰姆	Internally limitediFU嘉泰姆	mWiFU嘉泰姆
Thermal Resistance (TO252)iFU嘉泰姆 (Junction to Ambient, No Heatsink, Free Air)iFU嘉泰姆	RJAiFU嘉泰姆	50iFU嘉泰姆	oC/WiFU嘉泰姆
Operating Junction TemperatureiFU嘉泰姆	TJiFU嘉泰姆	-40 to 125iFU嘉泰姆	oCiFU嘉泰姆
Storage TemperatureiFU嘉泰姆	TSTGiFU嘉泰姆	-65 to 150iFU嘉泰姆	oCiFU嘉泰姆
Lead Temperature (Soldering, 10 sec)iFU嘉泰姆	TLEADiFU嘉泰姆	260iFU嘉泰姆	oCiFU嘉泰姆
ESD (HBM)iFU嘉泰姆		2000iFU嘉泰姆	ViFU嘉泰姆

九,相关芯片选择指南iFU嘉泰姆
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降压型直流电源变换器芯片(大功率型)iFU嘉泰姆
产品型号iFU嘉泰姆	输入电压iFU嘉泰姆	开关电流iFU嘉泰姆	开关频率iFU嘉泰姆	电压版本iFU嘉泰姆	封装类型iFU嘉泰姆
CXSD6257iFU嘉泰姆	5V ~ 32ViFU嘉泰姆	4AiFU嘉泰姆	300KHziFU嘉泰姆	Adj (0.8V)iFU嘉泰姆	TO252-5LiFU嘉泰姆
CXSD6258iFU嘉泰姆	5V ~ 32ViFU嘉泰姆	5AiFU嘉泰姆	300KHziFU嘉泰姆	Adj (0.8V)iFU嘉泰姆	TO263-5LiFU嘉泰姆
CXSD6259iFU嘉泰姆	8V ~ 36ViFU嘉泰姆	4AiFU嘉泰姆	180KHziFU嘉泰姆	Adj (1.25V)iFU嘉泰姆	TO252-5LiFU嘉泰姆
CXSD6260iFU嘉泰姆	8V ~ 36ViFU嘉泰姆	5AiFU嘉泰姆	180KHziFU嘉泰姆	Adj (1.25V)iFU嘉泰姆	TO263-5LiFU嘉泰姆
CXSD6261iFU嘉泰姆	8V ~ 40ViFU嘉泰姆	8AiFU嘉泰姆	180KHziFU嘉泰姆	Adj (1.25V)iFU嘉泰姆	TO220-5LiFU嘉泰姆

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