目录w4u嘉泰姆

1.产品概述                       2.产品特点w4u嘉泰姆
3.应用范围                       4.下载产品资料PDF文档 w4u嘉泰姆
5.产品封装图                     6.电路原理图                   w4u嘉泰姆
7.功能概述                        8.相关产品w4u嘉泰姆

一,产品概述(General Description)   w4u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.w4u嘉泰姆
  The CXSD6295 is available in SOP-8P and TDFN3x3-10 packages.w4u嘉泰姆
二.产品特点(Features)w4u嘉泰姆

1.)Wide 5V to 12V Supply Voltagew4u嘉泰姆
2.)Power-On-Reset Monitoring on VCCw4u嘉泰姆
3.)Excellent Output Voltage Regulationsw4u嘉泰姆
     0.8V Internal Referencew4u嘉泰姆
     ±1% Over-Temperature Rangew4u嘉泰姆
4.)Integrated Soft-Startw4u嘉泰姆
5.)Voltage Mode PWM Operation with External Compensationw4u嘉泰姆
6.)Up to 90% Duty Ratio for Fast Transient Responsew4u嘉泰姆
7.)Constant Switching Frequency  300kHz ±10%w4u嘉泰姆
8.)9V Driver Voltage for BOOT Supply with Internal Bootstrap Diodew4u嘉泰姆
9.)Drive Dual Low Cost N-MOSFETs with Adaptive Dead-Time Controlw4u嘉泰姆
10.)50% Under-Voltage Protectionw4u嘉泰姆
11.)125% Over-Voltage Protectionw4u嘉泰姆
12.)Adjustable Over-Current Protection Thresholdw4u嘉泰姆
     Using the RDS(ON) of Low-Side MOSFETw4u嘉泰姆
13.)Shutdown Control by COMPw4u嘉泰姆
14.)Power Good Monitoring (TDFN-10 3mmx3mm Package Only)w4u嘉泰姆
    SOP-8P and TDFN3x3-10 Packagesw4u嘉泰姆
15.)Lead Free and Green Devices Available (RoHS Compliant)w4u嘉泰姆
三,应用范围 (Applications)w4u嘉泰姆

Graphic Cardsw4u嘉泰姆
DSL, Switch HUBw4u嘉泰姆
Wireless Lanw4u嘉泰姆
Notebook Computerw4u嘉泰姆
Mother Boardw4u嘉泰姆
LCD Monitor/TVw4u嘉泰姆
四.下载产品资料PDF文档 w4u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！w4u嘉泰姆

 w4u嘉泰姆

五,产品封装图 (Package)w4u嘉泰姆

w4u嘉泰姆

六.电路原理图w4u嘉泰姆

w4u嘉泰姆

七,功能概述w4u嘉泰姆

Output Capacitor Selectionw4u嘉泰姆
The selection of COUT is determined by the required effec-tive series resistance (ESR) and voltagew4u嘉泰姆
rating rather than the actual capacitance requirement. Therefore, selecting high performance low ESRw4u嘉泰姆
capacitors is intended for switching regulator applications. In some applications,multiple capacitors havew4u嘉泰姆
to be paralleled to achieve the desired ESR value. If tantalum capacitors are used, make sure they arew4u嘉泰姆
surge tested by the manufactures. If in doubt,consult the capacitors manufacturer. w4u嘉泰姆
Input Capacitor Selectionw4u嘉泰姆
The input capacitor is chosen based on the voltage rat-ing and the RMS current rating. For reliable operation,w4u嘉泰姆
select the capacitor voltage rating to be at least 1.3 times higher than the maximum input voltage. The maximumw4u嘉泰姆
RMS current rating requirement is approximately IOUT/2 where IOUT is the load current. During power up, thew4u嘉泰姆
input capacitors have to handle large amount of surge current.If tantalum capacitors are used, make sure theyw4u嘉泰姆
are surge tested by the manufactures. If in doubt, consult the ca-pacitors manufacturer.For high frequencyw4u嘉泰姆
decoupling, a ceramic capacitor be-tween 0.1μF to 1μF can connect between VCC and ground pin.w4u嘉泰姆
Inductor Selectionw4u嘉泰姆
The inductance of the inductor is determined by the out-put voltage requirement. The larger the inductance, w4u嘉泰姆

the lower the inductor’s current ripple. This will translate into lower output ripple voltage. The ripple current w4u嘉泰姆

and ripple voltage can be approximated by:w4u嘉泰姆
×   OUTw4u嘉泰姆
FSW × L    VINw4u嘉泰姆
where Fs is the switching frequency of the regulator.w4u嘉泰姆
∆VOUT = IRIPPLE x ESRw4u嘉泰姆
A tradeoff exists between the inductor’s ripple current and the regulator load transient response time. A smallerw4u嘉泰姆

 in-ductor will give the regulator a faster load transient re-sponse at the expense of higher ripple current and vicew4u嘉泰姆
versa. The maximum ripple current occurs at the maxi-mum input voltage. A good starting point is to choose thew4u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. w4u嘉泰姆
Compensationw4u嘉泰姆
The output LC filter of a step down converter introduces a double pole, which contributes with -40dB/decade gainw4u嘉泰姆
slope and 180 degrees phase shift in the control loop. A compensation network between COMP pin and groundw4u嘉泰姆
should be added. The simplest loop compensation net-work is shown in Figure 5.w4u嘉泰姆
The output LC filter consists of the output inductor and output capacitors. The transfer function of the LC filter isw4u嘉泰姆
given by:w4u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.w4u嘉泰姆

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