CXSD6295电压模式固定300kHz开关频率同步降压变换器许宽输入电压对于vario为单个5~12V或两个电源电压

目录f7l嘉泰姆

1.产品概述                       2.产品特点f7l嘉泰姆
3.应用范围                       4.下载产品资料PDF文档 f7l嘉泰姆
5.产品封装图                     6.电路原理图                   f7l嘉泰姆
7.功能概述                        8.相关产品f7l嘉泰姆

一,产品概述(General Description)   f7l嘉泰姆

 The CXSD6295 is a voltage mode, fixed 300kHz switching frequency, synchronous buck converter. The CXSD6295 allows wide input voltage that is either a single 5~12V or two supply voltage(s) for various applications. A power-on-reset (POR) circuit monitors the VCC supply voltage to prevent wrong logic controls. A built-in soft-start circuit prevents the output voltages from overshoot as well as limits the input current. An internal 0.8V tempera ture-compensated reference voltage with high accuracy is designed to meet the requirement of low output voltage applications. The CXSD6295 provides excellent out put voltage regulations against load current variation.The controller’s over-current protection monitors the out-put current by using the voltage drop across the RDS(ON) of low-side MOSFET, eliminating the need for a current sensing resistor that features high efficiency and low cost. In addition, the CXSD6295 also integrates excellent protection functions: The over-voltage protection (OVP) , under voltage protection (UVP). OVP circuit which monitors the FB voltage to prevent the PWM output from over-voltage,and UVP circuit which monitors the FB voltage to prevent the PWM output from under-voltage or short-circuit.f7l嘉泰姆
  The CXSD6295 is available in SOP-8P and TDFN3x3-10 packages.f7l嘉泰姆
二.产品特点(Features)f7l嘉泰姆

1.)Wide 5V to 12V Supply Voltagef7l嘉泰姆
2.)Power-On-Reset Monitoring on VCCf7l嘉泰姆
3.)Excellent Output Voltage Regulationsf7l嘉泰姆
     0.8V Internal Referencef7l嘉泰姆
     ±1% Over-Temperature Rangef7l嘉泰姆
4.)Integrated Soft-Startf7l嘉泰姆
5.)Voltage Mode PWM Operation with External Compensationf7l嘉泰姆
6.)Up to 90% Duty Ratio for Fast Transient Responsef7l嘉泰姆
7.)Constant Switching Frequency  300kHz ±10%f7l嘉泰姆
8.)9V Driver Voltage for BOOT Supply with Internal Bootstrap Diodef7l嘉泰姆
9.)Drive Dual Low Cost N-MOSFETs with Adaptive Dead-Time Controlf7l嘉泰姆
10.)50% Under-Voltage Protectionf7l嘉泰姆
11.)125% Over-Voltage Protectionf7l嘉泰姆
12.)Adjustable Over-Current Protection Thresholdf7l嘉泰姆
     Using the RDS(ON) of Low-Side MOSFETf7l嘉泰姆
13.)Shutdown Control by COMPf7l嘉泰姆
14.)Power Good Monitoring (TDFN-10 3mmx3mm Package Only)f7l嘉泰姆
    SOP-8P and TDFN3x3-10 Packagesf7l嘉泰姆
15.)Lead Free and Green Devices Available (RoHS Compliant)f7l嘉泰姆
三,应用范围 (Applications)f7l嘉泰姆

Graphic Cardsf7l嘉泰姆
DSL, Switch HUBf7l嘉泰姆
Wireless Lanf7l嘉泰姆
Notebook Computerf7l嘉泰姆
Mother Boardf7l嘉泰姆
LCD Monitor/TVf7l嘉泰姆
四.下载产品资料PDF文档 f7l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！f7l嘉泰姆

 f7l嘉泰姆

五,产品封装图 (Package)f7l嘉泰姆

f7l嘉泰姆

六.电路原理图f7l嘉泰姆

f7l嘉泰姆

七,功能概述f7l嘉泰姆

Output Capacitor Selectionf7l嘉泰姆
The selection of COUT is determined by the required effec-tive series resistance (ESR) and voltagef7l嘉泰姆
rating rather than the actual capacitance requirement. Therefore, selecting high performance low ESRf7l嘉泰姆
capacitors is intended for switching regulator applications. In some applications,multiple capacitors havef7l嘉泰姆
to be paralleled to achieve the desired ESR value. If tantalum capacitors are used, make sure they aref7l嘉泰姆
surge tested by the manufactures. If in doubt,consult the capacitors manufacturer. f7l嘉泰姆
Input Capacitor Selectionf7l嘉泰姆
The input capacitor is chosen based on the voltage rat-ing and the RMS current rating. For reliable operation,f7l嘉泰姆
select the capacitor voltage rating to be at least 1.3 times higher than the maximum input voltage. The maximumf7l嘉泰姆
RMS current rating requirement is approximately IOUT/2 where IOUT is the load current. During power up, thef7l嘉泰姆
input capacitors have to handle large amount of surge current.If tantalum capacitors are used, make sure theyf7l嘉泰姆
are surge tested by the manufactures. If in doubt, consult the ca-pacitors manufacturer.For high frequencyf7l嘉泰姆
decoupling, a ceramic capacitor be-tween 0.1μF to 1μF can connect between VCC and ground pin.f7l嘉泰姆
Inductor Selectionf7l嘉泰姆
The inductance of the inductor is determined by the out-put voltage requirement. The larger the inductance, f7l嘉泰姆

the lower the inductor’s current ripple. This will translate into lower output ripple voltage. The ripple current f7l嘉泰姆

and ripple voltage can be approximated by:f7l嘉泰姆
×   OUTf7l嘉泰姆
FSW × L    VINf7l嘉泰姆
where Fs is the switching frequency of the regulator.f7l嘉泰姆
∆VOUT = IRIPPLE x ESRf7l嘉泰姆
A tradeoff exists between the inductor’s ripple current and the regulator load transient response time. A smallerf7l嘉泰姆

 in-ductor will give the regulator a faster load transient re-sponse at the expense of higher ripple current and vicef7l嘉泰姆
versa. The maximum ripple current occurs at the maxi-mum input voltage. A good starting point is to choose thef7l嘉泰姆
ripple current to be approximately 30% of the maximum output current.Once the inductance value has been chosen, selecting an inductor is capable of carrying the required peak cur-rent without going into saturation. In some types of inductors, especially core that is make of ferrite, the ripple current will increase abruptly when it saturates. This will result in a larger output ripple voltage. f7l嘉泰姆
Compensationf7l嘉泰姆
The output LC filter of a step down converter introduces a double pole, which contributes with -40dB/decade gainf7l嘉泰姆
slope and 180 degrees phase shift in the control loop. A compensation network between COMP pin and groundf7l嘉泰姆
should be added. The simplest loop compensation net-work is shown in Figure 5.f7l嘉泰姆
The output LC filter consists of the output inductor and output capacitors. The transfer function of the LC filter isf7l嘉泰姆
given by:f7l嘉泰姆
The FLC is the double poles of the LC filter, and FESR is the zero introduced by the ESR of the output capacitor.f7l嘉泰姆

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