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參數(shù)資料
| 型號(hào)： | MAX8508ETE |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類(lèi)： | 穩(wěn)壓器 |
| 英文描述： | PWM Step-Down DC-DC Converters with 75m? Bypass FET for WCDMA and cdmaOne Handsets |
| 中文描述： | 3.2 A SWITCHING REGULATOR, 1200 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封裝： | 4 X 4 MM, 0.80 MM HEIGHT, MO-220, TQFN-16 |
| 文件頁(yè)數(shù)： | 9/12頁(yè) |
| 文件大?。?/td> | 382K |
| 代理商： | MAX8508ETE |
M
PWM Step-Down DC-DC Converters with 75m
Bypass FET for WCDMA and cdmaOne Handsets
_______________________________________________________________________________________
9
capacitor ripple. This sets the device speed for transient
response and allows the use of small ceramic output
capacitors because the phase-shifted capacitor ripple
does not disturb the current-regulation loop. The resistor
sets the proportional gain of the output error voltage by
a factor of g
m
x R
C
. Increasing this resistor also increas-
es the sensitivity of the control loop to output ripple.
The resistor and capacitor set a compensation zero that
defines the system’s transient response. The load cre-
ates a dynamic pole, shifting in frequency with changes
in load. As the load decreases, the pole frequency
shifts to the left. System stability requires that the com-
pensation zero must be placed to ensure adequate
phase margin (at least 30° at unity gain). With a 4.7μF
output capacitor, the recommended C
C
and R
C
for the
MAX8506 are 1500pF and 10k
, respectively. This pro-
vides adequate phase margin over the entire output
voltage and load range and optimizes the output-
voltage settling time for REFIN dynamic control. See the
Typical Application Circuits
for recommended C
C
and
R
C
values for the MAX8507 and MAX8508.
Inductor Selection
A 4μH to 6μH inductor is recommended for most appli-
cations. For best efficiency, the inductor’s DC resistance
should be <400m
. Saturation current (I
SAT
) should be
greater than the maximum DC load at the PA’s supply
plus half the inductor current ripple. Two-step V
CC
applications typically require very small inductors with
I
SAT
in the 200mA to 300mA region. See Tables 1 and 2
for recommended inductors and suppliers.
PC Board Layout and Routing
Table 2. Component Suppliers
High switching frequencies and large peak currents
make PC board layout a very important part of design.
Good design minimizes EMI, noise on the feedback
paths, and voltage gradients in the ground plane, all of
which can result in instability or regulation errors.
Connect the inductor, input filter capacitor, and output fil-
ter capacitor as close together as possible and keep their
traces short, direct, and wide. The external voltage- feed-
back network should be very close to the FB pin, within
0.2in (5mm). Keep noisy traces, such as those from the
LX pin, away from the voltage-feedback network. Position
the bypass capacitors as close as possible to their
respective supply and ground pins to minimize noise cou-
pling. For optimum performance, place input and output
capacitors as close to the device as possible. Connect
GND directly under the IC to the exposed paddle. Refer
to the MAX8506 evaluation kit for an example PC board
layout and routing scheme.
SUPPLIER
Murata
Sumida
Taiyo Yuden
TOKO
PHONE
770-436-1300
847-956-0666
408-573-4150
847-297-0070
WEBSITE
www.murata.com
www.sumida.com
www.t-yuden.com
www.tokoam.com
Table 1. Suggested Inductors
SUPPLIER
PART
NUMBER
INDUCTANCE
(μH)
ESR (m
)
SATURATION
CURRENT (A)
DIMENSIONS (mm)
Murata
Sumida
Taiyo Yuden
TOKO
LQH32C-53
CDRH2D11
LBLQ2016
D312C
4.7
4.7
4.7
4.7
150
135
250
200
0.650
0.500
0.210
0.790
2.5 x 3.2 x 1.7
3.2 x 3.2 x 1.2
1.6 x 2.0 x 1.6
3.6 x 3.6 x 1.2
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| MAX8508ETE+ | 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 DC/DC Converter DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| MAX8508ETE+T | 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 DC/DC Converter DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| MAX8508ETE-T | 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 DC/DC Converter DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| MAX850CSA | 功能描述:電荷泵 RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| MAX850CSA-T | 功能描述:電荷泵 RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
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