参数资料
| 型号： | XRP7657EDTR-F |
| 厂商： | Exar Corporation |
| 文件页数： | 7/11页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 2A 8SOIC |
| 标准包装： | 1 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.8 V ~ 21 V |
| 输入电压： | 4.75 V ~ 25 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 420kHz |
| 电流 - 输出： | 2A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 剪切带 (CT) |
| 供应商设备封装： | 8-SOICN |
| 其它名称： | 1016-1381-1 |
X R P 7 6 5 7
2 A , 2 5 V N o n S y n c h r o n o u s P W M S t e p D o w n R e g u l a t o r
APPLICATION INFORMATION
SELECTING DIODE
D1
THEORY OF OPERATION
XRP7657 is a non-synchronous voltage mode
PWM buck regulator featuring an integrated
P-channel switching FET. Using a PFET enables
the regulator to operate at 100% duty cycle.
Additional features include preset switching
frequency of 420kHz and preset soft-start.
Safety features include under-voltage lock-Out
(UVLO), over-current protection (OCP), over-
temperature protection (OVP) and short-circuit
protection.
T YPICAL A PPLICATION S CHEMATICS
D1 must be a Schottky diode and selected for
Voltage rating V R , current rating I F and power
rating P. The voltage rating should be greater
than V IN in order to block the input voltage
when the internal PFET is on. As a rule of
thumb D1 voltage rating should be 50% larger
than V IN . A simplified rule for current rating is
to select a diode capable of conducting the
converter’s output current.
S ELECTING INDUCTOR L1
L1 should have saturation current rating I SAT
greater than the converter output current. As
a rule of thumb I SAT should be twice the output
current.
The inductance value can be calculate from
the following equation:
1
1
?
Where:
S ETTING THE OUTPUT VOLTAGE
Output voltage V OUT is set by placing a resistor
divider between output of the regulator and
feedback pin. Resistors R 1 and R 2 are
calculated from the following equation:
1
V IN is converter input voltage
V OUT is converter output voltage
f is the nominal switching frequency, 420kHz
Δ IL is the peak to peak inductor current ripple usually
set to 30% of I OUT
O UTPUT CAPACITOR SELECTION
Either ceramic or ALEL capacitors can be used.
Select the output capacitor for voltage rating,
Where V REF is the reference
internally at 0.8V nominal.
voltage
set
capacitance and Equivalent Series Resistance
(ESR). Nominally the voltage rating is selected to be
twice as large as the output voltage. Select the
E NABLE SIGNAL
The Enable pin can be used to turn the
regulator on and off. Pulling the Enable below
0.7V puts the regulator in shutdown mode
with a corresponding quiescent current of less
than 60μA. If Enable is not going to be used it
should be tied to V IN .
capacitance to satisfy the specification for output
voltage overshoot/undershoot caused by current step
load. A steady-state output current I OUT corresponds
to inductor stored energy of ? x L x I OUT2 . A sudden
decrease in I OUT forces the energy surplus in L to be
absorbed by C OUT . This causes an overshoot in
output voltage that is corrected by power switch
reduced duty cycle. Use the following equation to
calculate C OUT :
? 2011 Exar Corporation
7/11
Rev. 2.0.0
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相关代理商/技术参数 |
参数描述 |
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| XRP7657EVB | 功能描述:电源管理IC开发工具 Eval Board for XRP7657 Series RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| XRP7659 | 制造商:EXAR 制造商全称:EXAR 功能描述:1.5A 18V1.4MHz Non Synchronous Step-Down Regulator |
| XRP7659EVB | 功能描述:电源管理IC开发工具 EVAL XRP7659 RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| XRP7659ISTR-F | 功能描述:直流/直流开关转换器 4.5-18Vin,.18-15Vout 1.5A, DC Converter RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| XRP7662 | 制造商:EXAR 制造商全称:EXAR 功能描述:12A 300KHz Synchronous Step Down Regulator |
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