参数资料
型号: MAX1627ESA
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: 稳压器
英文描述: 5V/3.3V or Adjustable, 100% Duty-Cycle, High-Efficiency, Step-Down DC-DC Controllers
中文描述: 0.05 A SWITCHING CONTROLLER, 300 kHz SWITCHING FREQ-MAX, PDSO8
封装: 0.150 INCH, MS-012A, SOIC-8
文件页数: 10/16页
文件大小: 185K
代理商: MAX1627ESA
M
With high inductor values, the MAX1626/MAX1627 will
begin continuous-conduction operation at a lower frac-
tion of the full load (see Detailed Description. Low-value
inductors may be smaller and less expensive, but they
result in greater peak current overshoot due to current-
sense comparator propagation delay. Peak-current
overshoot reduces efficiency and could cause the exter-
nal components’ current ratings to be exceeded.
The inductor’s saturation and heating current ratings
must be greater than the peak switching current to pre-
vent overheating and core saturation. Saturation occurs
when the inductor’s magnetic flux density reaches the
maximum level the core can support, and inductance
starts to fall. The heating current rating is the maximum
DC current the inductor can sustain without overheating.
The peak switching current is the sum of the current limit
set by the current-sense resistor and overshoot during
current-sense comparator propagation delay.
1μs is the worst-case current-sense comparator propa-
gation delay.
Inductors with a core of ferrite, Kool Mu, METGLAS,
or equivalent, are recommended. Powder iron cores
are not recommended for use with high switching
frequencies. For optimum efficiency, the inductor wind-
ings’ resistance should be on the order of the current-
sense resistance. If necessary, use a toroid, pot-core,
KOOL Mu is a trademark of Magnetics.
METGLAS is a trademark of Allied Signal.
or shielded-core inductor to minimize radiated noise.
Table 1 lists inductor types and suppliers for various
applications.
External S witc hing T ransistor
The MAX1626/MAX1627 drive P-channel enhancement-
mode MOSFETs. The EXT output swings from GND to
the voltage at V+. To ensure the MOSFET is fully on,
use logic-level or low-threshold MOSFETs when the
input voltage is less than 8V. Tables 1 and 2 list recom-
mended suppliers of switching transistors.
Four important parameters for selecting a P-channel
MOSFET are drain-to-source breakdown voltage, cur-
rent rating, total gate charge (Q
g
), and R
DS(ON)
. The
drain-to-source breakdown voltage rating should be at
least a few volts higher than V+. Choose a MOSFET
with a maximum continuous drain current rating higher
than the peak current limit:
The Qg specification should be less than 100nC to
ensure fast drain voltage rise and fall times, and reduce
power losses during transition through the linear region.
Q
g
specifies all of the capacitances associated with
charging the MOSFET gate. EXT pin rise and fall times
vary with different capacitive loads, as shown in the
Typical Operating Characteristics. R
DS(ON)
should be
as low as practical to reduce power losses while the
MOSFET is on. It should be equal to or less than the
current-sense resistor.
I
D(MAX
LIM MAX
I
(
CS MAX
V
R
SENSE
)
)
(
)
=
I
= V
R
V
V
L
PEAK
CS
CS
OUT
+
+
(
)
× μ
5V /3.3V or Adjustable, 100% Duty-Cyc le,
High-Effic ienc y, S tep-Down DC-DC Controllers
10
______________________________________________________________________________________
PRODUCTION
METHOD
INDUCTORS
CAPACITORS
DIODES
CURRENT-SENSE
RESISTORS
MOSFETS
Surface Mount
AVX
TPS series
Sprague
595D series
Motorola
MBRS340T3
Nihon
NSQ series
Dale
WSL series
IRC
LRC series
Miniature
Through-Hole
Sumida
RCH875-470M (1.3A)
Sanyo
OS-CON series
low-ESR organic
semiconductor
IRC
OAR series
Motorola
Low-Cost
Through-Hole
CoilCraft
PCH-45-473 (3.4A)
Motorola
1N5817 to
1N5823
Motorola
TMOS power MOSFETs
Sumida
CDRH125-470 (1.8A)
CDRH125-220 (2.2A)
CoilCraft
DO3316-473 (1.6A)
DO3340-473 (3.8A)
Siliconix
Little Foot series
Motorola
medium-power
surface-mount products
Nichicon
PL series
low-ESR electrolytics
United Chemi-Con
LXF series
Table 1. Component Selection Guide
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相关代理商/技术参数
参数描述
MAX1627ESA+ 功能描述:DC/DC 开关控制器 5/3.3V or Adjustable 100% Duty Cycle RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
MAX1627ESA+ 制造商:Maxim Integrated Products 功能描述:CONTROLLER STEP DOWN DC-DC 1627 制造商:Maxim Integrated Products 功能描述:CONTROLLER, STEP DOWN, DC-DC, 1627
MAX1627ESA+G071 功能描述:DC/DC 开关控制器 Adjustable 100% Duty-Cycle High-Efficiency Step-Down DC-DC Controller RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
MAX1627ESA+T 功能描述:DC/DC 开关控制器 5/3.3V or Adjustable 100% Duty Cycle RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
MAX1627ESA+TG071 功能描述:DC/DC 开关控制器 5V/3.3V or Adjustable 100% Duty Cycle High-Efficiency Step-Down DC-DC Controllers RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK