参数资料
| 型号： | TPS54260DRCR |
| 厂商： | Texas Instruments |
| 文件页数： | 33/52页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 2.5A 10SON |
| 标准包装： | 3,000 |
| 系列： | SWIFT™, Eco-Mode™ |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.8 V ~ 58 V |
| 输入电压： | 3.5 V ~ 60 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 100kHz ~ 2.5MHz |
| 电流 - 输出： | 2.5A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 150°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-VFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 10-SON 裸露焊盘（3x3） |
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SLVSA86A – MARCH 2010 – REVISED DECEMBER 2010
The slow start time must be long enough to allow the regulator to charge the output capacitor up to the output
voltage without drawing excessive current. Equation 40 can be used to find the minimum slow start time, tss,
necessary to charge the output capacitor, Cout, from 10% to 90% of the output voltage, Vout, with an average
slow start current of Issavg. In the example, to charge the effective output capacitance of 72.4 μF up to 3.3V
while only allowing the average output current to be 1 A would require a 0.19 ms slow start time.
Once the slow start time is known, the slow start capacitor value can be calculated using Equation 6 . For the
example circuit, the slow start time is not too critical since the output capacitor value is 2 x 47 m F which does not
require much current to charge to 3.3V. The example circuit has the slow start time set to an arbitrary value of
3.5 ms which requires a 8.75 nF slow start capacitor. For this design, the next larger standard value of 10 nF is
used.
Tss >
Cout ′ Vout ′ 0.8
Issavg
(40)
Bootstrap Capacitor Selection
A 0.1- m F ceramic capacitor must be connected between the BOOT and PH pins for proper operation. It is
recommended to use a ceramic capacitor with X5R or better grade dielectric. The capacitor should have a 10V
or higher voltage rating.
Under Voltage Lock Out Set Point
The Under Voltage Lock Out (UVLO) can be adjusted using an external voltage divider on the EN pin of the
TPS54260. The UVLO has two thresholds, one for power up when the input voltage is rising and one for power
down or brown outs when the input voltage is falling. For the example design, the supply should turn on and start
switching once the input voltage increases above 6.0 V (enabled). After the regulator starts switching, it should
continue to do so until the input voltage falls below 5.5 V (UVLO stop).
The programmable UVLO and enable voltages are set using the resistor divider of R1 and R2 between Vin and
ground to the EN pin. Equation 2 through Equation 3 can be used to calculate the resistance values necessary.
For the example application, a 124 k ? between Vin and EN (R1) and a 30.1 k ? between EN and ground (R2)
are required to produce the 6.0 and 5.5 volt start and stop voltages.
Output Voltage and Feedback Resistors Selection
The voltage divider of R5 and R6 is used to set the output voltage. For the example design, 10.0 k ? was
selected for R6. Using Equation 1 , R5 is calculated as 31.25 k ? . The nearest standard 1% resistor is 31.6 k ? .
Due to current leakage of the VSENSE pin, the current flowing through the feedback network should be greater
than 1 m A in order to maintain the output voltage accuracy. This requirement makes the maximum value of R2
equal to 800 k ? . Choosing higher resistor values will decrease quiescent current and improve efficiency at low
output currents but may introduce noise immunity problems.
Compensation
There are several methods used to compensate DC/DC regulators. The method presented here is easy to
calculate and ignores the effects of the slope compensation that is internal to the device. Since the slope
compensation is ignored, the actual cross over frequency will usually be lower than the cross over frequency
used in the calculations. This method assumes the crossover frequency is between the modulator pole and the
esr zero and the esr zero is at least 10 times greater the modulator pole. Use SwitcherPro software for a more
accurate design.
To get started, the modulator pole, fpmod, and the esr zero, fz1 must be calculated using Equation 41 and
Equation 42 . For Cout, use a derated value of 40 m F. Use equations Equation 43 and Equation 44 , to estimate a
starting point for the crossover frequency, fco, to design the compensation. For the example design, fpmod is
1206 Hz and fzmod is 530.5 kHz. Equation 43 is the geometric mean of the modulator pole and the esr zero and
Equation 44 is the mean of modulator pole and the switching frequency. Equation 43 yields 25.3 kHz and
Equation 44 gives 13.4 kHz. Use the lower value of Equation 43 or Equation 44 for an initial crossover frequency.
For this example, a higher fco is desired to improve transient response. the target fco is 35.0 kHz. Next, the
compensation components are calculated. A resistor in series with a capacitor is used to create a compensating
zero. A capacitor in parallel to these two components forms the compensating pole.
Copyright ? 2010, Texas Instruments Incorporated
Product Folder Link(s): TPS54260
33
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| TPS54260DRCT | 功能描述:直流/直流开关转换器 3.5V-60Vin,2.5A,2.5 MHz Step Down SWIFT 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 |
| TPS54260EVM-597 | 功能描述:电源管理IC开发工具 2.5A,10.8-13.2Vin SWIFT Conv Eval Mod 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 |
| TPS54260MDGQTEP | 功能描述:IC REG BUCK ADJ 2.5A 10MOSP 制造商:texas instruments 系列:Eco-Mode? 包装:剪切带（CT） 零件状态:在售 功能:降压 输出配置:正 拓扑:降压 输出类型:可调式 输出数:1 电压 - 输入（最小值）:3.5V 电压 - 输入（最大值）:60V 电压 - 输出（最小值/固定）:0.8V 电压 - 输出（最大值）:60V 电流 - 输出:2.5A 频率 - 开关:100kHz ~ 2.5MHz 同步整流器:无 工作温度:-40°C ~ 150°C（TJ） 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 供应商器件封装:10-MSOP-PowerPad 标准包装:1 |
| TPS54260MDRCTEP | 功能描述:IC REG BUCK ADJ 2.5A 10VSON 制造商:texas instruments 系列:Eco-Mode? 包装:剪切带（CT） 零件状态:在售 功能:降压 输出配置:正 拓扑:降压 输出类型:可调式 输出数:1 电压 - 输入（最小值）:3.5V 电压 - 输入（最大值）:60V 电压 - 输出（最小值/固定）:0.8V 电压 - 输出（最大值）:60V 电流 - 输出:2.5A 频率 - 开关:100kHz ~ 2.5MHz 同步整流器:无 工作温度:-40°C ~ 150°C（TJ） 安装类型:表面贴装 封装/外壳:10-VFDFN 裸露焊盘 供应商器件封装:10-VSON（3x3） 标准包装:1 |
| TPS54260-Q1 | 制造商:TI 制造商全称:Texas Instruments 功能描述:3.5 V to 60 V STEP DOWN CONVERTER WITH ECO-MODEa?￠ |
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