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参数资料
| 型号： | TPS54426PWP |
| 厂商： | TEXAS INSTRUMENTS INC |
| 元件分类： | 稳压器 |
| 英文描述： | 7.5 A SWITCHING REGULATOR, 700 kHz SWITCHING FREQ-MAX, PDSO14 |
| 封装： | GREEN, PLASTIC, HSSOP-14 |
| 文件页数： | 5/26页 |
| 文件大小： | 945K |
| 代理商： | TPS54426PWP |
Ilp-p=
V
OUT
V
IN(max)
V
-V
IN(max)
OUT
L
f
O
SW
I
=I +
lpeak
O
Ilp-p
2
I
=
Lo(RMS)
√
I +
O
2
1
12
Ilp-p
2
I
=
CO(RMS)
V
OUT
(
)
V-V
IN
OUT
V
IN
L
O
f
SW
√12
www.ti.com
SLVSAD6B – AUGUST 2010 – REVISED NOVEMBER 2010
At low frequencies, the overall loop gain is set by the output set-point resistor divider network and the internal
gain of the TPS54426. The low frequency phase is 180 degrees. At the output filter pole frequency, the gain rolls
off at a -40 dB per decade rate and the phase drops rapidly. D-CAP2 introduces a high frequency zero that
reduces the gain roll off to -20 dB per decade and increases the phase to 90 degrees one decade above the
zero frequency. The inductor and capacitor selected for the output filter must be selected so that the double pole
of Equation 5 is located below the high frequency zero but close enough that the phase boost provided be the
high frequency zero provides adequate phase margin for a stable circuit. To meet this requirement use the
values recommended in Table 1
Table 1. Recommended Component Values
Output Voltage (V)
R1 (k
Ω)
R2 (k
Ω)
C4 (pF)(1)
L1 (H)
C8 + C9 (F)
1
6.81
22.1
1.5
22 - 68
1.05
8.25
22.1
1.5
22 - 68
1.2
12.7
22.1
1.5
22 - 68
1.8
30.1
22.1
10 - 22
2.2
22 - 68
2.5
49.9
22.1
10 - 22
2.2
22 - 68
3.3
73.2
22.1
10 - 22
2.2
22 - 68
5
121
22.1
10 - 22
3.3
22 - 68
(1)
Optional
For higher output voltages at or above 1.8 V, additional phase boost can be achieved by adding a feed forward
capacitor (C4) in parallel with R1.
Since the DC gain is dependent on the output voltage, the required inductor value will increase as the output
voltage increases. For higher output voltages above 1.8 V, additional phase boost can be achieved by adding a
feed forward capacitor (C4) in parallel with R1
The inductor peak-to-peak ripple current, peak current and RMS current are calculated using Equation 6,
Equation 7 and Equation 8. The inductor saturation current rating must be greater than the calculated peak
current and the RMS or heating current rating must be greater than the calculated RMS current. Use 700 kHz for
fSW.
(6)
(7)
(8)
For this design example, the calculated peak current is 4.47A and the calculated RMS current is 4.009 A. The
inductor used is a TDK SPM6530-1R5M100 with a peak current rating of 11.5 A and an RMS current rating of 11
A.
The capacitor value and ESR determines the amount of output voltage ripple. The TPS54426 is intended for use
with ceramic or other low ESR capacitors. Recommended values range from 22uF to 68uF. Use Equation 9 to
determine the required RMS current rating for the output capacitor
(9)
For this design two TDK C3216X5R0J226M 22uF output capacitors are used. The typical ESR is 2 m
Ω each.
The calculated RMS current is .271A and each output capacitor is rated for 4A.
Input Capacitor Selection
The TPS54426 requires an input decoupling capacitor and a bulk capacitor is needed depending on the
application. A ceramic capacitor over 10 uF. is recommended for the decoupling capacitor. An additional 0.1 F
capacitor from pin 14 to ground is recommended to improve the stability of the over-current limit function. The
capacitor voltage rating needs to be greater than the maximum input voltage.
Copyright 2010, Texas Instruments Incorporated
13
Product Folder Link(s) :TPS54426
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相关代理商/技术参数 |
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| TPS54426PWP | 制造商:Texas Instruments 功能描述:IC BUCK SYNC ADJ 14HTSSOP 制造商:Texas Instruments 功能描述:IC, BUCK, SYNC, ADJ, 14HTSSOP 制造商:Texas Instruments 功能描述:IC, BUCK, SYNC, ADJ, 14HTSSOP; Primary Input Voltage:18V; No. of Outputs:1; Output Current:10mA; Voltage Regulator Case Style:HTSSOP; No. of Pins:14; Operating Temperature Min:-40C; Operating Temperature Max:85C; SVHC:No SVHC ;RoHS Compliant: Yes |
| TPS54426PWPR | 功能描述:直流/直流开关转换器 4.5-18V Inp,4A Synch SWIFT 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 |
| TPS54426RSAR | 功能描述:直流/直流开关转换器 4.5V-18Vin,4A Synch 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 |
| TPS54426RSAT | 功能描述:直流/直流开关转换器 4.5V-18Vin,4A Synch 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 |
| TPS54427 | 制造商:TI 制造商全称:Texas Instruments 功能描述:4.5V to 18 V Input, 4-A Output Single Synchronous Step-Down Switcher with Integrated FET (SWIFTa?￠) |
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