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參數(shù)資料
| 型號： | MAX741NEAP |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Current-Mode SMPS Controller |
| 中文描述： | 1 A SWITCHING CONTROLLER, 160 kHz SWITCHING FREQ-MAX, PDSO20 |
| 封裝： | 0.65 MM PITCH, SHRINK, SOP-20 |
| 文件頁數(shù)： | 10/12頁 |
| 文件大?。?/td> | 231K |
| 代理商： | MAX741NEAP |
V
DD
V
SUPPLY
IN
CLK
GND
INPUT
OUTPUT
50k
50k
50k
OUT
COM
0.1
μ
F
0.1
μ
F
0.1
μ
F
CLOCK
SHDN
OS
MAX7400
MAX7403
MAX7404
MAX7407
Figure 4. Offset Adjustment Circuit
M
8th-Order, Lowpass, Elliptic ,
S witc hed-Capac itor Filters
10
______________________________________________________________________________________
Cloc k S ignal
External Clock
The MAX7400/MAX7403/MAX7404/MAX7407 SCFs
were designed for use with external clocks that have a
40% to 60% duty cycle. When using an external clock,
drive CLK with a CMOS gate powered from 0 to V
DD
.
Varying the rate of the external clock adjusts the filter
corner frequency:
f
C
= f
CLK
/ 100
Internal Clock
When using the internal oscillator, the capacitance
(C
OSC
) on the CLK pin determines the oscillator fre-
quency:
(kHz) = K 10
C
OSC
where K = 38 for the MAX7400/MAX7403, and K = 34
for the MAX7404/MAX7407. Since the capacitor value
is in picofarads, minimize the stray capacitance at CLK
so that it does not affect the internal oscillator frequen-
cy. Varying the rate of the internal oscillator adjusts the
filter’s corner frequency by a 100:1 clock-to-corner fre-
quency ratio. For example, an internal oscillator fre-
quency of 100kHz produces a nominal corner
frequency of 1kHz.
Input Impedanc e
vs. Cloc k Frequenc ies
The MAX7400/MAX7403/MAX7404/MAX7407’s input
impedance is effectively that of a switched-capacitor
resistor and is inversely proportional to frequency. The
input impedance determined by the following equation
represents the average input impedance, since the
input current is not continuous. As a rule, use a driver
with an output source impedance less than 10% of the
filter’s input impedance. Estimate the input impedance
of the filter using the following formula:
where f
CLK
= clock frequency and C
IN
= 0.85pF.
Low-Power S hutdown Mode
These devices feature a shutdown mode that is activat-
ed by driving
SHDN
low. Placing the filter in shutdown
mode reduces the supply current to 0.2μA (typ) and
places the output of the filter into a high-impedance
state. For normal operation, drive
SHDN
high or con-
nect to V
DD
.
Applic ations Information
Offset and Common-Mode
Input Adjustment
The voltage at COM sets the common-mode input volt-
age and is internally biased at midsupply by a resistor-
divider. Bypass COM with a 0.1μF capacitor and
connect OS to COM. For applications requiring offset
adjustment or DC level shifting, apply an external bias
voltage through a resistor-divider network to OS, as
shown in Figure 4. (Note: Do not leave OS unconnect-
ed.) The output voltage is represented by the following
equation:
V
OUT
= (V
IN
- V
COM
) + V
OS
Z
f
C
IN
CLK
IN
( )
(
)
=
1
f
OSC
3
;
C
in pF
OSC
PASSBAND
STOPBAND
G
FREQUENCY
f
C
f
S
f
S
f
C
f
S
f
C
TRANSITION RATIO=
RIPPLE
Figure 3. Elliptic Filter Response
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參數(shù)描述 |
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| MAX741NEAP-T | 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| MAX741NEPP | 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| MAX741NMJP | 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| MAX741UC/D DIE | 制造商:Maxim Integrated Products 功能描述: |
| MAX741UCAP | 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
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